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In order to improve the driving performance of electric vehicles (EV), a permanent magnet synchronous motor with double V-shaped magnet structure (DVMPMSM) and its driving system are studied in this paper. A 150 kW DVMPMSM for EV is designed firstly, and the design parameters of the motor are determined. In order to overcome the drawbacks of the finite element analysis (FEA), especially the issue on calculating time, a dynamic equivalent magnetic network (EMN) model of the DVMPMSM is constructed, by which the air gap flux density, back electromotive force, electromagnetic torque and winding inductance parameters of the motor can be solved. Compared with the FEA, the dynamic EMN model constructed in this paper greatly increases the calculation speed while the calculation accuracy is maintained well. This paper also introduces the stator winding switching method to replace the field-weakening control method. Then, a vector control method of DVMPMSM based on dynamic EMN model and stator winding switching is proposed. The demands brought forward by EV for high torque output under low speed and high upper limit of speed can be well satisfied. Finally, the accuracy of the dynamic EMN model and the effectiveness of the proposed control method is validated through prototype experiments.

For the requirements of in-wheel traction systems, a new motor is proposed based on a specific property of multiphase machines: the ability in vector control to develop smooth torque at low speeds by using simultaneously the first and third harmonics to generate p and 3p polarities. From an initial fault-tolerant seven-phase axial–flux machine with two outer axial rotors for small vehicles such as moto/scooter is born the proposed motor just by adding magnets in the cylinder closing the two 2p-pole axial rotors of initial in-wheel motor, this addition creates thus a third radial rotor with 6p poles without changing the global volume. With an increase by 51% of the torque density, this more expensive motor can be considered in comparison with the initial in-wheel motor as a modular solution. With the same volume, a higher torque for higher acceleration and slopes can be obtained. The possibility to use different polarities with a strong non-sinusoidal back-emf without torque ripples is verified in 3D-FEM simulation and in a manufactured 28 slots – 12/36 poles prototype. Experimental results are given to prove the effectiveness of the proposal.

Two approaches are commonly used for modelling and control of nine-phase (triple star) fault-tolerant machines with symmetrical and asymmetrical star winding configurations: The Vector Space Decomposition (VSD) and the decentralized d-q modelling. In this paper, it will be shown how the VSD approach used for machines with an Asymmetrical Star Winding Configuration (ASWC), unlike the decentralized d-q one used for machines with a Symmetrical Star Winding Configuration (SSWC), can be helpful for non-intrusive Fault Detection and Diagnosis (FDD) purposes. Supporting MATLAB/Simulink simulations are discussed.

As one of the key components, low-speed direct-drive in-wheel machines with high compact volume and high torque density are important for the traction system of electric vehicles (EVs). This paper introduces four different types of outer-rotor permanent magnet motors for EVs, including one five-phase SPM machine, one three-phase IPM machine with V-shaped PMs, one seven-phase axial flux machine (AFM) of sandwich structure and finally one hybrid flux (radial and axial) machine with a third rotor with V-shaped PMs added to the AFM. Firstly, the design criteria and basic operation principle are compared and discussed. Then, the key properties are analyzed using the Finite Element Method (FEM). The electromagnetic properties of the four fractional slot tooth concentrated winding in-wheel motors with similar dimensions are quantitatively compared, including air-gap flux density, electromotive force, field weakening capability, torque density, losses, and fault tolerant capability. The results show that the multi-phase motors have high torque density and high fault tolerance and are suitable for direct drive applications in EVs.

For non-sinusoidal electromotive force (NS-EMF) multiphase machines, this paper proposes a new strategy and control scheme to guarantee smooth torque under an open-phase fault. Notably, the conventional proportional-integral (PI) controllers implemented for vector control in healthy mode can be used in the faulty mode. The strategy is based on reduced-order transformations while the control scheme applies a simple artificial intelligence algorithm using a specific online-trained Adaptive Linear Neuron (ADALINE). Indeed, the inputs of ADALINE require the knowledge of rotor position and NS-EMF harmonic rank to optimize the learning time. The proposed strategy and control scheme are tested on a seven-phase machine with a strong Total Harmonic Distortion (THD) of NS-EMFs, containing numerous harmonics Hk (THD=38% with 100% H1, 32.3% H3, 9.4% H7, 12.5% H9, 10.3% H11). Numerical and experimental results are presented in this paper. This paper is accompanied by a video demonstrating the experimental results.

Fault tolerance has been known as one of the main advantages of multiphase drives. When an open-circuit fault happens, smooth torque can be obtained without any additional hardware. However, a reconfiguration strategy is required to determine new reference currents. Despite advantages of non-sinusoidal electromotive forces (NS-EMFs) such as high torque density, multi-harmonics existing in NS-EMFs cause more challenges for control, especially under faulty conditions. Therefore, to guarantee high-quality vector control of multiphase drives with multi-harmonic NS-EMFs, this two-part study proposes control schemes using adaptive linear neurons (Adalines) to adaptively eliminate torque ripples. The proposed simple Adalines are efficient because of taking advantage of the knowledge of rotor position and of torque harmonic rank induced by the NS-EMFs. The control scheme using an Adaline for healthy mode was described in part I of this study. In this second part, the control scheme using another Adaline for an open-circuit operation, under the impacts of multi-harmonics in NS-EMFs, is proposed. Notably, smooth torque and similar copper losses in the remaining healthy phases can be obtained. Experimental tests are carried out on a seven-phase permanent magnet synchronous machine (PMSM) with a high total harmonic distortion (THD = 38%) of NS-EMFs. A demonstration video is provided with this paper.

This two-part study proposes a new sensorless control strategy for non-sinusoidal multiphase permanent magnet synchronous machines (PMSMs), especially in integrated motor drives (IMDs). Based on the Sliding Mode Observer (SMO), the proposed sensorless control strategy uses the signals (currents and voltages) of all fictitious machines of the multiphase PMSMs. It can estimate the high-accuracy rotor position that is required in the vector control. This proposed strategy is compared to the conventional sensorless control strategy applying only current and voltage signals of the main fictitious machine, including the fundamental component of back electromotive force (back-EMF) of the non-sinusoidal multiphase PMSMs. Therefore, in order to choose an appropriate sensorless control strategy for the non-sinusoidal multiphase PMSMs, these two sensorless control strategies will be highlighted in terms of precision in the rotor position and speed estimations. Simulation and experimental results of a non-sinusoidal seven-phase PMSM will be shown to verify and compare the two sensorless control strategies. In this part of the study (part I), only the sensorless control in medium and high-speed range is considered. The sensorless control at zero and low-speed range will be treated in the second part of this study (part II).

This paper proposes a sensorless control strategy based on Sliding Mode Observer (SMO) for a Five-phase Interior Permanent Magnet Synchronous Machine (FIPMSM), with a consideration of the third harmonic component. Compared to conventional three-phase machines, the third harmonic of back electromotive force (back-EMF) contains more information. Thus, in this paper, the first and third harmonic components of the five-phase machine are considered to estimate the rotor position which is necessary for the vector control. Simulation results are shown to verify the feasibility and the robustness of the proposed sensorless control strategy.

More degrees of freedom not only enable multiphase drives to be fault-tolerant but also allow non-sinusoidal electromotive forces (NS-EMFs) in high-quality vector control. NS-EMFs lead to lower costs of design and manufacturing of electrical machines. However, the presence of multi-harmonics in NS-EMFs possibly generates pulsating torque in both healthy and faulty conditions of multiphase drives. To facilitate the use of NS-EMFs, this two-part study proposes control schemes to adaptively improve torque quality of multiphase drives in dealing with multi-harmonics of NS-EMFs. The proposed schemes are based on a simple but effective type of artificial intelligence, Adaptive Linear Neuron (Adaline). The knowledge of multiphase drives including the harmonic ranks of NS-EMFs and the rotor position is exploited to design the online-trained optimal Adalines. The first part of this study is to propose a control scheme using an Adaline for healthy mode with high-quality torque regardless of numerous harmonics in NS-EMFs. The second part of this study introduces a control scheme using another Adaline for open-circuit faults. The proposed schemes are numerically and experimentally validated on a seven-phase permanent magnet synchronous machine (PMSM) possessing a high total harmonic distortion (THD=38%) of NS-EMFs. A demonstration video is provided with this paper.

In this paper, a novel five-phase fractional-slot concentrated winding (FSCW) with 20-slot/22-pole is presented. It benefits not only the advantages of conventional FSCW, but also weak space harmonics of magnetomotive force (mmf). The winding allows eliminating the 1st sub-order harmonic. The new layout of the winding topology is obtained by a combination of stator shift technique of the winding in the slots with a special coupling of the windings (star-pentagon), using winding function theory. The high performances of the new winding layout are validated using finite element method (FEM). Compared to the conventional winding, the winding factor and the THD of mmf are improved by 1.3% and 2.2%, respectively. With the same injection of current density, the average output torque is increased by 1% and the torque ripple is decreased by 60%. The eddy current losses in the PMs at rated speed (600 rpm) and 2100 rpm speed are improved by 67% and 56%, respectively.

This paper presents a diagnostic method of inverter open-switch and open-phase faults in multiphase PMSM drives. Adequate variables called “Virtual Current Vectors (VCVn)” are firstly defined. The projection of the zero-sequence current component (ZSCC) on these variables was used to define two simple fault indices. High sensitivity to fault is thus induced but with a good robustness to transient states and variation of machine parameters. The mathematical development of the proposed method is provided and supported by experimental tests conducted on two prototypes of multiphase machines in the laboratory, sinusoidal and bi-harmonic PMSMs. The experimental results confirm the effectiveness and the robustness of the proposed method and its capability to detect the single and multiple open-switches and open-phase faults in the electric drive.

This paper investigates a real-time fault diagnostic of a transportation system which needs two drives with fault-tolerance capabilities. Because of constraints on the mass of the system and on the cost of the Voltage Source Inverter (VSI), a drive with two Six-Phase Permanent Magnet Synchronous Machines (PMSM) in series-connection supplied by two six-leg inverters is chosen. Despite the serial -connection, independent control of the two machines and fault –tolerance to open-switch fault is ensured. Nevertheless, a Fault Detection Identification (FDI) process is required for analysis and/or control reconfiguration. The proposed FDI is based on the combination of different criteria obtained from the two zero-sequence currents and from the normalized currents mapped into two frames defined by the Concordia Transformation. Results obtained from simulation and experimental tests show the effectiveness of the proposal.

If multi-phase machines equipped with tooth concentrated winding with half a slot per pole and per phase offer interesting characteristics (simplified manufacturing, no space subharmonic, fault-tolerant ability), their low fundamental winding factors make their designs and controls challenging. The paper addresses the case of a seven-phase Surface-mounted Permanent Magnet (SPM) machine which has a fundamental winding factor lower than the third. This so-called bi-harmonic specificity is considered in order to achieve good torque quality (average value and ripples). Regarding the design, the magnet layer is segmented into two identical radially magnetized tiles that cover about three-quarters the pole arc. Regarding the control, the rated Maximum Torque Per Ampere (MTPA) supply strategy (h1h3 control) aims at generating a third harmonic current component greater than the fundamental. A prototype has been manufactured: the ability of the machine to provide smooth torque is experimentally confirmed through the implementation of a simple MTPA control which copes with high distortion in no-load voltage.

For three-phase induction machines supplied by sinusoidal current, it is usual to model the n-bar squirrel-cage by an equivalent two-phase circuit. For a multiphase induction machine which can be supplied with different harmonics of current, the reduced-order model of the rotor must be more carefully chosen in order to predict the pulsations of torque. The proposed analysis allows to avoid a wrong design with non-sinusoidal magnetomotive forces. An analytical approach is proposed and confirmed by Finite-Element modelling at first for a three-phase induction machine and secondly for a five-phase induction machine.

In the context of future Permanent Magnet Synchronous Machines (PMSMs) with a high number of phases (>7) in integrated drives, this paper proposes several control strategies when multiphase PMSMs with non-sinusoidal back electromotive forces (back-EMFs) operate in healthy and open-circuit faults. In all operation modes, the considered constraint on current is related to the maximum root mean square (RMS) current allowable in one phase of the machine. The constraint on voltage limits the maximum peak value of the phase voltage determined by the DC-bus voltage of the converter. When one or two phases are open-circuited, to maximize torque and respect the constraints, new current references obtained by several proposed methods in rotating and natural frames are imposed to the machine. Due to the non-sinusoidal waveform of back-EMFs and the considered constraints, numerical computations based on analytical formulations are required to obtain maximal torque-speed characteristics, including the flux-weakening operation. The usefulness of the proposed strategies is verified by numerical and experimental results.

This paper proposes several easy-to-implement control strategies when seven-phase axial flux brushless DC machines with trapezoidal back electromotive forces operate in normal and faulty modes by taking into account constraints on voltage and current. The constraints are related to the converter and machine design in terms of maximum values of current and voltage. The considered faults are cases in which one or two phases of the machine are open-circuited. Numerical computations based on analytical formulations are applied to obtain torque-speed characteristics, including the flux-weakening operation. The methods determine current references to ensure the torque optimizations while currents and voltages are within their limits. The usefulness of the methods is verified by numerical results.

Multiphase machines have recently gained interest in the research community for their use in applications where high power density, wide speed range and fault-tolerant capabilities are required. The optimal control of such drives requires the consideration of voltage and current limits imposed by the power converter and the machine. While conventional three-phase drives have been extensively analyzed taking into account such limits, the same cannot be said in the multiphase drives’ case. This paper deals with this issue, where a novel two-stage Model Predictive optimal Control (2S-MPC) technique is presented, and a five-phase permanent magnet synchronous multiphase machine (PMSM) is used as a case example. The proposed method first applies a Continuous-Control-Set Model Predictive Control (CCS-MPC) stage to obtain the optimal real-time stator current reference for given DC-link voltage and stator current limits, exploiting the maximum performance characteristics of the multiphase drive. Then, a Finite-Control-Set Model Predictive Control (FCS-MPC) stage is utilized to generate the switching state in the power converter and force the stator current tracking. An experimental validation of the proposed controller is finally provided using a real-time simulation environment based on OPAL-RT technologies.

In the context of traction drives with required torque transient capabilities and a classically wide flux weakening speed range, this paper gives design considerations of a particular Double-Polarity (DP) five-phase machine. Beyond its intrinsic fault tolerance due its five phases, it specificity is the ability to develop torques of comparable values under three kinds of supply: with only first, third or both first and third sinusoidal currents. This property, due to first (E1) and third (E3) harmonic electromotive forces (emf) of comparable values, gives more degrees of freedom for the control of the machine. Unlike three-phase sinusoidal machine, flux weakening is no more the unique solution when maximum voltage is reached. Thanks to the extra degrees of freedom in this kind of machines, more possibilities for the control of the torque and current supply can be applied. At first, elements for the choice of slots/poles combination of such DP machines are given. Then, in case of an Interior Permanent Magnet Synchronous Machine (IPMSM), possible adaptations of the rotor are proposed in order to bring the double p/3p polarity property. The last design criterion considered is the level of eddy-current losses, important at high frequencies. For proof of the concept effectiveness, a prototype with a five-phase fractional-slot concentrated winding of 40 slots and 16/48 poles is presented with results from experimental set-up and Finite Element modeling. A comparison with equivalent no-fault-tolerant three-phase 24 slots /16 poles machines is also carried out

High cost, no-ideal driving range and charge time limit electric vehicle market share. Facing these challenges, an integrated motor drive/battery charger system has been proposed by Valeo. A further advancement, based on this system, is present in this paper; for the first time, the integration of traction, charging and air-compressor supply modes is proposed and tested by real-time experimentation. This integrated system is expected to increase the vehicle component compactness and power, therefore potentially reduce the cost and battery charging time. An overall and unique control scheme is detailed to achieve the three main operating modes: traction, charging and air-compressor supply modes. The real-time experimentation results show the system feasibility.

This paper presents an extension of previous methods in order to find electrical series-connections between multiphase machines allowing the independent control of each one of them. These new electrical series-connections explore the symmetrical disposition of the phases of even-multiphase machines, allowing the inversed connection of some of the phases, different from the direct connections as it was previously done. Therefore, electrical series-connections of two symmetrical 6-phase or of four symmetrical 10-phase machines are now possible. Besides that, this new solution ensures a natural independent control of permanent magnet synchronous machines even if the back-electromotive forces generated by the rotor are not sinusoidal, without need of special machine conception or supplementary control strategy. This control independency is mathematically proved using the decomposition of multiphase machines in fictitious diphase and homopolar machines. Experimental results are presented to show the functioning and the advantages of this new coupling for two symmetrical 6-phase permanent magnet synchronous machines.

This paper proposes a procedure that is suitable for experimental investigation of real-time open-switch and open-phase faults diagnosis of a five-leg Voltage Source Inverter (VSI) feeding a five-phase bi-harmonic Permanent Magnet Synchronous Machine (5-Φ B-PMSM). The algorithm is based on the specific characteristics of multiphase machines, which allows inverter fault detection with sufficient robustness of the algorithm in the presence of fundamental and third harmonic components. Firstly, the inverter fault effects analysis is achieved in the characteristic subspaces of the five-phase PMSM. Specificities that are interesting for the elaboration of a real-time Fault Detection and Identification (FDI) process are highlighted. Original and particular algorithms are used for an accurate two-dimensional normalized fault vector extraction in a defined fault reference frame. This frame is dedicated only for fault detection and identification. To ensure the high immunity of the FDI process against transient states, a particular normalization procedure is applied. The normalized diagnostic signals are formulated from the defined frame and others variables derived from the reference and measured currents. Simulation and experimental results of open-switch and open-phase faults are provided to validate the proposed algorithm.

This paper analyzes two fault-tolerant dual-multiphase motor drives, a series connected topology and a standard H-bridge topology. Previous studies have shown that the series connected topology is appropriate to an aerospace application and has lower peak current in degraded mode in comparison with the H-bridge topology, which may consequently diminish the system’s weight and cost. This paper extends the study to compare different control strategies of these structures under two fault conditions: short-circuit of an inverter’s switch and an open-phase of the machine. The control strategies analyzed in this paper do not impact the fundamental current or the torque generation, but the amplitudes of some harmonics in degraded mode are expected to be narrowed down in order to reduce the inverter’s size. Some analyses of maximum voltage and peak current in degraded mode have been used for inverter dimensioning. Experimental results are shown and compared to the simulated ones to confirm the validity of this study.

This paper proposes a novel variable speed control strategy of a particular 5-phase Permanent Magnet Synchronous Generator (PMSG) in healthy and faulty modes by taking into account the constraints on voltages and currents. These constraints are related to the converter and machine design. The considered faults are open-circuited phases (one phase, two adjacent phases and two non-adjacent phases). A variable speed control strategy is presented, including flux weakening operations. Based on analytical formulations, a numerical computation is proposed to bring out the torque-speed characteristics. This method allows the determination of the current references which ensure the functioning of a 5-phase PMSG at variable speed while keeping phase voltages and currents below their limits. Theoretical, numerical and experimental results are presented. These results are compared in order to validate the proposed approach.

The purpose of the paper is to present the potentialities in terms of the control of a new kind of PM synchronous machine. With five phases and electromotive forces whose first ( ) and third ( ) harmonics are of similar amplitude, the studied machine, so-called bi-harmonic, has properties that are interesting for traction machine payload. With three-phase machines, supplied by a mono-harmonic sinusoidal current, the weak number of freedom degrees limits the strategy of control for traction machines especially when voltage saturation occurs at high speeds. As the torque is managed for three-phase machines by a current with only one harmonic, flux weakening is necessary to increase speed when the voltage limitation is reached. The studied five-phase machine, thanks to the increase in the number of freedom degrees for control, aims to alleviate this fact. In this paper, three optimized control strategies are compared in terms of efficiency and associated torque/speed characteristics. These strategies take into account numerous constraints either from the supply (with limited voltage) or from the machine (with limited current densities and maximum acceptable copper, iron and permanent magnet losses). The obtained results prove the wide potentialities of such a kind of five-phase bi-harmonic machine in terms of control under constraints. It is thus shown that the classical Maximum Torque Per Ampere (MTPA) strategy developed for the three-phase machine is clearly not satisfying on the whole range of speed because of the presence of iron losses whose values can no more be neglected at high speeds. Two other strategies have been then proposed to be able to manage the compromises, at high speeds, between the high values of torque and efficiency under the constraints of admissible total losses either in the rotor or in the stator.

A novel centroid-based diagnostic method of the power switches in five-leg Voltage Source Inverter (VSI) is proposed in this paper. Using a vectorial multi-machine description, a five-phase drive presenting an opened switch or an opened phase faults has typical operating characteristics in comparison to classical three-phase drives. Based on such characteristics, this work aims to provide a simple and robust diagnostic process for switches fault regardless of the shape of the back-EMFs (harmonic components) and the transient states due to the load variation. Original theoretical developments are presented. Experimental results are shown to validate the proposed strategy.

In this paper, the study of the torque and power versus speed characteristics for a family of five-phase Surfacemounted Permanent Magnet (SPM) machine is carried out. With considering hypotheses (linear magnetic modeling, only first and third harmonic terms in the back-emf and current spectrums), an optimization problem that aims to maximize the torque for given maximum peak voltage and RMS current is formulated: the optimal torque sharing among the two virtual machines (the two dq-axis subspaces) that represent the real five-phase machine is thus calculated for any mechanical speed. For an inverter and a DC voltage sized with only considering the first harmonic of backemf and current, the problem is solved with changing the virtual machine back-emfs and inductances ratios. With the introduction of the maximum torque/speed point, maximum power/speed point and maximum reachable speed, it can be shown that, if the inductance ratio is large enough, for given Volt-Ampere rating, the machine can produce higher torque without reducing its speed range thus meaning that the capability of the inverter to work is improved with the use of the third harmonic. This property is all the truer as the base armature reaction is large. A particular five-phase machine is sized and numerically analyzed to check this property.

Multiphase machines are more and more used in applications where a high power density, a low bus voltage, a wide speed range and possibilities to work in fault mode are required. Due to the high number of available degrees of freedom, multiphase machines are not easy to optimally control in the flux weakening region. This paper shows several strategies for the control of multiphase machines in flux weakening regions and compares them in terms of simplicity to implement and optimality in the use of available quantities. Proposed strategies are applied to a five-phase synchronous machine that has been developed for the MHYGALE project proposed by Valeo company.

Multi-phase machines are well-known for their fault tolerant capability. Star-connected multiphase machines have fault tolerance in open-circuit. For inverter switch short-circuit fault, it is possible to keep a smooth torque of Permanent Magnet Synchronous Machine (PMSM) if the currents of faulty phases are determined and their values are acceptable. This paper investigates fault-tolerant operations of an open-end five-phase drive, i.e. a multi-phase machine fed with a dual-inverter supply. Inverter switch short-circuit fault is considered and handled with a simple solution. Original theoretical developments are presented. Simulation and experimental results validate the proposed strategy.

This paper presents and compares control strategies for three-phase open-end winding drives operating in the flux-weakening region. A six-leg inverter with a single dc-link is associated with the machine in order to use a single energy source. With this topology, the zero-sequence circuit has to be considered since the zero-sequence current can circulate in the windings. Therefore, conventional over-modulation strategies are not appropriate when the machine enters in the flux-weakening region. A few solutions dealing with the zero-sequence circuit have been proposed in literature. They use a modified space vector modulation or a conventional modulation with additional voltage limitations. The paper describes the aforementioned strategies and then a new strategy is proposed. This new strategy takes into account the magnitudes and phase angles of the voltage harmonic components. This yields better voltage utilization in the dq frame. Furthermore, inverter saturation is avoided in the zero-sequence frame and therefore zero-sequence current control is maintained. Three methods are implemented on a test bed composed of a three-phase permanent-magnet synchronous machine, a six-leg inverter and a hybrid DSP/FPGA controller. Experimental results are presented and compared for all strategies. A performance analysis is conducted as regards the region of operation and the machine parameters.

This paper deals with an on-line method for turn-to-turn short-circuit fault detection in low-voltage permanent-magnet synchronous machine drives. Due to the closed-loop control, the fault effects are reflected in the voltage. Therefore, an appropriate diagnostic index is proposed, which is derived from the positive- and negative-sequences of the voltage references. These sequences are obtained in the time domain via adaptive filters, which require only a few calculations. To increase the sensitivity to the fault, the algorithm is only applied to a part of the voltage references, i.e. the output of the proportional-integral controllers. Further, the cumulative-sum algorithm is introduced to cope with changes of small magnitudes. This algorithm allows a change of a fault index to be detected and can be used as a decision system. The resulting fault detection scheme is computationally cheap and can be embedded in the control unit. Simulations and experimental results validate the proposed method in steady state and the performances under non-stationary operating conditions are also investigated.

Some surrogate-assisted optimization techniques are applied in order to improve the performances of a 5-phase Permanent Magnet (PM) machine in the context of a complex model requiring computation time. An optimal control of four independent currents is proposed in order to minimize the total losses with the respect of functioning constraints. Moreover, some geometrical parameters are added to the optimization process allowing a co-design between control and dimensioning. The effectiveness of the method allows solving the challenge which consists in taking into account inside the control strategy the eddy-current losses in magnets and iron. In fact, magnet losses are a critical point to protect the machine from demagnetization in flux-weakening region. But these losses, which highly depend on magnetic state of the machine, must be calculated by Finite Element Method (FEM) to be accurate. The FEM has the drawback to be time consuming. It is why, a direct optimization using FEM is critical. The response surface method (RSM) and the Efficient Global Optimization (EGO) algorithm consist in approximating the FEM by a surrogate model used directly or indirectly in the optimization process. The optimal results proved the interest of the both methods in this context

this paper studies magnet eddy-current losses in permanent magnet (PM) machines with concentrated winding. First of all, space harmonics of magnetomotive force (MMF) and their influence on magnet losses in electrical machines are investigated. Secondly, analytical model of magnet volume losses is developed by studying the interaction between MMF harmonics wavelengths and magnet pole dimensions. Different cases of this interaction are exhibited according to the ratio between each harmonic wavelength and magnet pole width. Then various losses sub-models are deduced. Using this analytical model, magnet volume losses for many Slots/Poles combinations of 3, 5, and 7 phase machines with concentrated winding are compared. This comparison leads to classify combinations into different families depending on their magnet losses level. Finally, in order to verify the theoretical study, Finite Element models are built and simulation results are compared with analytical calculations.

In this study, a three-phase drive with a six-leg voltage source inverter and an open-end winding interior permanent magnet synchronous machine designed for traction of an electric vehicle is studied in a flux-weakening operation. The topology allows the functionality of a high-power charger to be obtained, without adding any other supplementary power devices. On the other hand, since there are three independent currents, the control structure has to handle not only the two dq-current components but also a zero-sequence current. If neglected, in comparison with a wye-coupled three-phase drive, this zero-sequence component can cause a higher maximum peak value of the phase currents, additional stator Joule losses, torque ripple, inverter voltage saturation and insulated gate bipolar transistor (IGBT) oversizing. The proposed control strategy consists in adapting a conventional method used for wye-connected machines particularly in flux-weakening operation. This strategy allows the closed-loop control of the zero-sequence current to be maintained in the whole speed range and therefore inverter saturation is avoided. Simulations and experimental results are presented and analysed.

A general method for fault detection and isolation is proposed and applied to inverter faults in drives of electric vehicles. This method is based on a change-detection algorithm, which allows multiple fault indices to be combined for retrieving the most likely state of the drive. The considered drive topology is a six-leg inverter associated with a three-phase machine. Due to the inherent fault-tolerant topology, the conventional fault indices are no longer effective. Therefore, an analysis of simulations in faulty conditions leads to the derivation of suitable fault indices. These are based on the envelope of the phase currents as well as their instantaneous frequency. Specific operating conditions related to the electric vehicle environment are taken into account, such as the flux-weakening region and energy recovery. Finally, the performances of the fault detection and isolation scheme are evaluated under steady state and non-stationary conditions through simulations and experimental results.

The basis of an independent control of two 5-phase PM machines, connected in series to a single inverter, are presented.  The influence of the harmonics of the EMF of the PM machines in the behavior of the system is discussed.  An original strategy to determine optimal torque reference of each PM machine is presented.  Experimental and simulation results demonstrated the efficiency and the robustness of the proposed strategy.  The presented strategy leads to reach high level requirements in terms of torque quality.

Cet article est consacré à l’étude d’une méthode de commande d’une machine synchrone à aimant permanent à cinq phases associée à un onduleur de tension à MLI. On s’intéresse au cas de la commande en mode normal et en mode dégradé. Les défauts étudiés sont liés à la déconnexion d’une phase ou de plusieurs phases. Dans ce cas, la méthode étudiée est basée sur une approche vectorielle permettant la détermination en ligne des courants de référence optimaux adaptés au défaut. L’étude se propose de comparer l’utilisation de régulateurs PID avec des régulateurs non linéaire de type hystérésis à bande fixe et à bande adaptative. Cette comparaison est effectuée en mode normal et en mode de défaut. Les résultats de simulation effectués sur MATLAB / Simulink sont présentés et discutés afin de vérifier les performances de la stratégie et des régulateurs étudiés. Ils montrent en particulier que si la régulation de type PID est performante en mode normal, elle ne permet pas d’assurer un suivi correct des références en mode de défaut car celles ci présentent des variations dynamiques importantes. Dans ce dernier cas d’étude l’utilisation de commandes non linéaires comme la commande par hystérésis est nécessaire et permet de garder le même schéma de commande en mode normal et dégradé. L’utilisation d’une commande par hystérésis à bande adaptative est alors judicieuse car elle permet de bonnes performances de suivi et une maitrise de la fréquence de commutation de l’onduleur. The use of multiphase PM machines associated with VSI drives appears to be a very efficient solution. Presented work focus on the use of such a system in open circuited phase fault conditions. With this kind of system it is possible to determine optimal currents references which maximize the torque density of the system when one or two phases are open circuited. Classical linear controllers (as PID for example) cannot provide a correct tracking of these optimal reference currents because they have a highly dynamical behavior. We propose in this paper to combine this optimal reference current generation with hysteresis control. This kind of solution allows a good tracking of these unconventional reference currents with a fixed switching frequency for the VSI. In this case of adaptive hysteresis band control appears to be particularly efficient.

This paper deals with the generation of optimal current references for Multiphase Permanent Magnet Synchronous Machines in normal or fault mode (open-circuited phases). Current references are computed in order to keep a constant torque while minimizing instantaneous Joule losses. In comparison with commonly used scalar methods, a vectorial approach makes it possible to reduce the number of computations in order to generate optimal current references, in real-time. In addition to this, since current references are expressed in terms of physical parameters of the machine, this approach can be used to evaluate the influence of the machine parameters over the control performances. Finally, experimental results of a surface mounted permanent magnet five-phase synchronous machine are provided in order to demonstrate the proposed strategy.

Français RÉSUMÉ. Cet article établit un modèle causal unique pour les fonctionnements normal et dégradé d’un entraînement électromécanique à phases non couplées en s’appuyant sur un formalisme vectoriel et une Représentation Energétique Macroscopique (REM). L’inversion systématique du modèle permet de déduire une architecture de commande dans laquelle des correcteurs spécifiques sont utilisés pour assurer les deux modes de fonctionnement. Les validations en simulation, l’examen des performances en mode dégradé par rapport au mode normal et plusieurs validations expérimentales mettent en évidence la validité de la commande établie. Enfin, la méthode développée dans l’article pour les machines triphasées est adaptable aux machines polyphasées pour mettre en évidence la généralité de la méthode. MOTS-CLÉS : machines polyphasées, machines alternatives triphasées, filtrage de couple, commande auto adaptée, entraînements électromécaniques tolérants aux pannes. Anglais ABSTRACT. This paper deals with a unique causal model in normal and open-circuited phase operation of a electromechanical drive with independent supplied phases. This overall degraded system model is based on a vectorial formalism and the Energetic Macroscopic Representation (EMR). The systematic inversion of the model leads to a control structure using a dedicated controller available in the two operating modes. The simulating validation, the performances verifications in open-circuited mode versus normal mode and the experimental validations establish the validity of the control. Finally, this tree-phase method is adaptable to polyphase machines to bring to light the generality of the method. KEYWORDS: multiphase machines, alternative machines, torque filtering, auto adaptable control, fault tolerant drives.

This paper, which deals with the winding modeling of AC multi-phase machines with a regular distribution of the stator slots, details an original matrix modeling of the stator winding. First, the properties of the balanced multi-phase windings (with integral-slot and fractional-slot patterns) are analysed. The winding function approach, one of the most common way to model the winding distribution effects on the stator rotating field, is then introduced. For multi-phase machines, it will be shown that the pole number generated by the winding distribution depends on a new parameter: the circularity index. The discrete nature of the winding, imposed by the stator slots, leads to the development of a discrete modeling of the winding obtained from sampling the winding function: two matrices, the winding function matrix and the distribution function matrix, are introduced to characterize the multi-phase winding. This matrix approach is thus a concise way to calculate the winding factors and to estimate the set of self and mutual stator inductances for smooth air gap multi-phase machines. A particularly original method of obtaining an analytical expression for the leakage mutual inductance is described. The results are validated with two experimental 5-phase PM machines by using experimental measurements and numerical simulations.

This paper presents a design methodology dedicated to multiphase Permanent Magnet Synchronous Machines (PMSM) supplied by Pulse Width Modulation Voltage Source Inverters (PWM VSI). Firstly opportunities for increasing torque density using the harmonics are con- sidered. The specific constraints due to the PWM supply of multiphase machines are also taken into account during the design phase. All the defined constraints are expressed in a simple manner by using a multimachine modelling of the multiphase machines. This multimachine design is then applied in order to meet the specifications of a marine propeller: verifying simultaneously four design constraints, an initial 60-pole 3-phase machine is converted into a 58-pole 5-phase machine without changing the geometry and the active volume (iron, copper and magnet). Firstly, a specific fractional-slot winding, which yields to good characteristics for PWM supply and winding factors, is chosen. Then, using this winding, the magnet layer is designed to improve the flux focussing. According to analytical and numerical calculations, the five-phase machine provides a higher torque (about 15%) and less pulsating torque (71% lower) than the initial three-phase machine with the same copper losses.

This paper deals with easy to implement control strategies when a seven-phase Axial Flux Permanent Magnet machine (AFPM) supplied by a seven-leg Voltage Source Inverter (VSI) is in fault operation mode. Using a vectorial multi-machine description, a seven-phase machine presenting a heightened ability to be controlled with one or two open-circuited phases has been designed. The machine is first presented and experimental results are provided when one or two phases are open-circuited. Based on a vectorial approach, new current references are calculated to avoid high torque ripples.

This paper deals with fault tolerant multiphase electrical drives. The quality of the torque of vector-controlled Permanent Magnet (PM) Synchronous Machine supplied by a multi-leg Voltage Source Inverter (VSI) is examined in normal operation and when one or two phases are open-circuited. It is then deduced that a seven-phase machine is a good compromise allowing high torque-to-volume density and easy control with smooth torque in fault operation. Experimental results confirm the predicted characteristics.

In this paper, a 7-phase Axial-flux Double-rotor Permanent Magnet Synchronous Machine is studied using analytical and Finite Element methods. This type of machine shows a higher sensitivity to the inductance harmonics and electromotive force (emf) compared with the 3-phase machines. So, the conventional analytical modeling method, in which only the first harmonic is taken into account, leads to significant errors in the determination of the control parameters, e.g. the frequency of Pulse Width Modulation Voltage Source Inverter. A multi-machine model explains the reasons for this sensitivity and a more sophisticated analytical method is used. Results are compared with those obtained by the 3-D FEM.

This paper presents the equivalence of multi-phase machines with a set a of 1-phase and 2-phase machines with no magnetic couplings. Two cases are then studied. First, a 5-phase machine supplied by a Voltage Source Inverter(VSI) is analyzed. Then, a model is established for a single 5-leg VSI supplying two 5-phase machines whose windings are connected in series.

Multi-phase motors are widely used in marine propulsion. In this paper, a Multi-machine modeling of Surface Mounted PM motors is presented and applied to a 5-phase one. The latter is proved to be equivalent to a set of two-phase fictitious machines each ones being characterized by a set of specific harmonic rank. A simple control consists in supplying each fictitious machine by a current which contains only one harmonic. A five phase machine is then supplied by currents with only both first and third harmonics. Considering this kind of control, it is proved that for given stator resistance and average torque the Joule losses and the torque ripple are minimized if a simple criterion on the harmonics of electromotive force at constant speed is fullfilled. Different structures of rotor are then compared to examine numerically which improvements can be practically obtained.

A vectorial formalism for analysis and design of polyphase synchronous machines without reluctance and saturation effects is described. We prove the equivalence of such a machine with a set of magnetically independent machines, which are electrically and mechanically coupled. Specific problems of polyphase machines can thus be favorably analyzed with this concept. Rules of conception and constraints on electric supply can be deduced. Moreover the vectorial approach, which generalizes the complex phasor method, can also be used to control n-leg Voltage Source Inverters. This methodology is applied to 3-phase and 6- phase synchronous machines.

A generic and simple control method is suggested for any multi-leg voltage-source-converter. A specific coding yields an inversion table allowing a fast practical implementation. Phase-to-phase voltage references have to be defined for such a table. This original control strategy is validated by experimental results for 2-leg, 3-leg, 4-leg and 5-leg structures supplying balanced and unbalanced multi-phase loads.

This paper deals with the study of an unconventional design of marine tidal turbine where the electrical generator is located in the periphery of the blades and where the magnetic gap is underwater. This kind of solution called "RIM DRIVEN" structure allows increasing the compactness and the robustness of the system. Due to the strong interaction of the multi physical phenomena, an electromagnetic model and a thermal model of the PM generator are associated with a hydrodynamic model of the blades and of the water flow in the underwater air gap. These models are used in a global coupled design approach in order to optimize, under constraints, the global efficiency of the system. This approach is illustrated in a case study which deals with the design of a 10m diameter tidal turbine. Proposed coupled models are validated by comparison with experimental data from the tests of an academic low power demonstrator

T-type multilevel inverters are a potential alternative because of their increased efficiency and low conduction losses. A conventional two-level inverter is extended with a bidirectional active switch to form a T-Type topology. There are a few T-Type MLIs formulated based on requirements and applications. This work provides a comparative analysis of three different T-Type five-level MLIs with a five-level cascaded H-Bridge converter. Four multi-carrier pulse width modulation (PWM) strategies, i.e., phase disposition PWM (PDPWM), phase opposition disposition- PWM (PODPWM), alternate phase opposition disposition-PWM (APODPWM), and Hybrid PWM schemes are implemented to evaluate the performance of these MLIs. They are operated over a wide range of modulation indices, and the converter output voltage, total harmonic distortion (THD), and characteristics are observed. MATLAB\Simulink environment is used for this comparative performance analysis.

At low speed, the traditional high frequency signal injection (HFSI) control strategy will lead to large torque ripple, and affect the estimation accuracy of the position/speed related to sensorless control algorithm, and finally lead to the problem of the system stability. Based on the characteristics of sevenphase Permanent Magnet Synchronous Machine (PMSM), this paper proposes a new sensorless control strategy in full speed range. In the zero/low speed range, HFSI method is applied to the 5th harmonic subspace, which reduce the torque ripple of the machine.. In the medium/high speed range, the sliding mode observer (SMO) is used in the 1st harmonic subspace to estimate the speed and position of the machine. The influences between the two methods are effectively reduced when exchanging from zero/low speed to medium/high speed range. Moreover, the estimated position and speed is more accurate and the torque ripple is smaller with the proposed sensorless control strategy. Finally, the effectiveness of the proposed strategy is verified by simulation results.

This paper presents a new approach to control properly the currents of a dual three-phase PMSM operating in open-circuit fault condition with a wide speed range. Using fault tolerant control strategies proposed in the literature lead to high frequency current components in the rotor frame. Operating at high speed required in some industrial applications induces a strong constraint on the current controllers. In this paper, a second transformation matrix resulting constant currents in the new frame is proposed. However, there is still a coupling between axes. Thus, a simple Adaptive Linear Neuron is proposed to decouple and enhance the performance of the current tracking. Comparative simulation results are shown for a 12slots/8poles dual three-phase PMSM to confirm the validity of the proposed method.

In previous research, a novel three-phase dual-stator axial flux permanent magnet machine characterized by the advantages of compact structure and low moment of inertia is proposed for industrial robot application. In order to improve its functional reliability furtherly, the dual threephase axial flux permanent magnet machine (DTP-AFPM) is firstly proposed. Benefiting from the combination of 12 slots/10 poles, the coil configuration of one stator disk can be modified to a dual three phase full-pitch winding straightforwardly, as a result, one kind of the DTP-AFPMs is achieved which is named as the no shift model in this paper. For eliminating the coil reconfiguration on each stator disk and the connection of the coils belonging to the same phase between two stator disks, the shift model which is based on the shift of the two stator disks to obtain the phasor difference between two three-phase windings is introduced. The characteristics and electromagnetic performances of these two models are analyzed and compared. However, it should be noted that the light-weight disk-type rotor of DTP-AFPMs also degrade the strength of the rotor. The proposed DTPAFPMs are more sensitive to the axial stress on the rotor which introduces not only the vibration and noise but also the deformation or even the damage of the rotor. Thus, the axial stress on the rotor is investigated and treated as a critical evaluation indicator. The axial stress is analyzed under both healthy and fault conditions and its distribution on the rotor is given on a 2-D plane.

In this paper, a novel topology of five-phase fractional-slot concentrated winding (FSCW) with selective magnetomotive force (MMF) harmonic elimination is proposed. Compared to traditional FSCW with stator shift technique, not only the parasitic sub- or sup-order harmonics of the MMF can be selectively reduced or eliminated, the non-overlapping characteristic is also kept. Firstly, based on 20-slot/22-pole single-layer (SL) winding topology, a dual five-phase 40-slot/22-pole one of SL winding with 1 st harmonic elimination is introduced. Secondly, a new 40-slot/22-pole of double-layer with selective harmonic reduction is presented. Finally, the high performances of the machine with the proposed winding topology are evaluated using finite element analysis (FEA), including air gap flux density, output torque, machines losses, etc.

For in-wheel machine, outer rotor machines appear as a natural solution. Practically these machines are either radial-flux with one rotor or axial-flux with two rotors. The paper is proposing a machine with three outer rotors with two different polarities in order to reduce useless end-windings while keeping an acceptable thickness for the radial-flux rotor and high torque quality. This Hybrid Flux Permanent Magnet original structure (named HFPM) is possible thanks to the use of seven phases. The third rotor can be considered as an option of an initial double-rotor axial-flux machine in order to increase the torque density. First, the machine structure and the winding design are presented; then, based on 3D finite element method, comparison between the two machines, with two or three rotors, are provided in terms of torque densities and qualities.

This paper proposes the design and development of a five-phase external rotor permanent magnet synchronous machine (PMSM) which is used for direct drive convey application. Firstly, the slot/pole combination of fraction slot concentrated winding (FSCW) is selected according to four criteria, which are the least common multiple (LCM) and the greatest common divisor (GCD), the winding factor and the MMF distribution; secondly, based on the design requirement, an analytical model of the proposed machine topology is built, and the initial machine parameters are then obtained; thirdly, the machine is optimized by combing the finite element model and the Kriging model, and the final optimal results are compared to the initial one. Detail design principles and performance characteristics of the proposed machine topology are presented and validated with finite element models.

integrated drives are becoming a target for manufacturers aiming at addressing the increasing market of electrical embedded systems, such as e-transportation systems. Anyway, the integration of the power converter inside the electrical machine induces challenges if compactness is required. Additionally to the research of the best choices for the power electronics, electromagnetic, and thermal components, interconnection issues also arise, leading to cope simultaneously with several physical challenges. This paper gives an example of a multidisciplinary approach to propose smart integrated drive solution dedicated to middle power embedded systems.

Automotive industry is evolving towards more fault-tolerant actuators to fulfill future autonomous vehicles requirements. Critical applications such as steering or braking have to resist to fault occurrences while being low cost due to mass production market. Considering these two criteria, multiphase electric drives offer a good tradeoff between increasing the degrees of freedom and limiting system oversizing. This paper proposes to compare three multiphase electric drives for electro-hydraulic power steering for trucks: a five-phase machine and a six-phase machine both fed by a full bridge inverter (FBI), and a seven-phase machine fed by a standard half-bridge inverter (HBI). Several comparison criteria are considered in the meantime: motor, electronics, control and manufacturing parameters. Some of criteria are obtained from finite-element analysis (FEA), while others are derived from analytic formula or dynamic simulations. criteria are evaluated for each drive and then results are discussed In the given low-voltage high-current application, H-bridge inverter topology seems to be a promising solution. Both five-phase and six-phase present similar results. However, six-phase drive could be more interesting, as it could be brought close to standard three-phase solutions and adapted to dual-lane supply.

This paper proposes a strategy using new transformation matrices to calculate new current references when a non-sinusoidal seven-phase permanent magnet synchronous machine (PMSM) has an open-circuited phase. The new current references allow to obtain a smooth torque with similar copper losses in the remaining healthy phases even when the back electromotive force (back-EMF) is non-sinusoidal. A real-time current learning process using an adaptive linear neural network (Adaline) is applied to extract from measured currents useful harmonic components in torque generation. It improves torque quality, especially at high speed, even when standard proportional-integral (PI) controllers are applied. In addition, similar copper losses in the remaining phases with the new current references can avoid overheating of windings. The effectiveness of the proposed control strategy is validated by numerical results.

Automotive safety applications will be soon a standard based on market evolution trends. Actuators performing safety operations, such as steering or braking, need to be more reliable with a low manufacturing cost. Multiphase drives seem to be a good alternative to actuators redundancy, as it offers greater degrees of freedom with at a limited extra cost. These drives have been studied for a while, especially in other industries such as ship propulsion or aeronautic actuator. However, comparison between multiphase drives for a given application is rare. In this paper, a methodology is proposed to evaluate several drives for a safety automotive application. Some manufacturing assumptions have been made in order to narrow the study to five, six and seven phase permanent magnet synchronous motors (PMSM). Machines have been modeled using 2-D finite elements analysis (FEA) software in order to extract their parameters which will be used in dynamic simulations. Based on the obtained results, each drive is evaluated according to defined criteria and best solutions are highlighted. Considering a low voltage high current application, full bridge inverter topologies feeding a six-phase motor seem to be a promising solution.

This paper presents a sensorless control strategy for seven-phase non-sinusoidal permanent magnet synchronous machine (NSPMSM) with high frequency signal injection (HFSI) method in 5th harmonic subspace. Seven-phase nonsinusoidal machine benefits high torque density due to the use of third harmonic components. Firstly, two torque generation strategy in different harmonic subspaces with the minimum injected rms value and amplitude of current is deduced in this paper. Secondly, in order to reinforce the reliabilities of multiphase machine, the HFSI sensorless control is employed. Comparing with traditional HFSI method, the proposed control strategy is achieved in 5th harmonic subspace, which can avoid the torque ripple caused by the injected signal. Finally, according to simulations results the two torque distribution method is validated and compared and the effectiveness of the HFSI method is verified.

This paper is to propose a control scheme, a combination of the classical field-oriented control (FOC) technique and artificial intelligence (AI), to obtain constant torques in multiphase non-sinusoidal permanent magnet synchronous machine (PMSM) drives. Higher torque density, easier fabrication, and lower costs are several advantages of non-sinusoidal back electromotive force (back-EMF) machines over sinusoidal ones. However, multi-harmonics existing in back-EMFs possibly generate torque ripples, reducing torque quality of the drive. Therefore, in this paper, an adaptive linear neuron (ADALINE), a simple type of AI, is combined with the classical FOC technique to eliminate these torque ripples. The proposed control scheme is validated by numerical results with a seven-phase PMSM. In addition, these results are compared with an existing strategy to prove its effectiveness.

This paper proposes a new sensorless control strategy based on a Sliding Mode Observer (SMO) for a non-sinusoidal Seven phase PMSMs. This strategy, based on all harmonics contained in the back-EMF, is compared to the classical sensorless control strategy using only the fundamental of back-EMF signal. As the novel sensorless control strategy estimate the rotor position by using different harmonics, it can lead to a good torque response compared to the classical strategy, specially in transient states. Therefore, in order to define the appropriate sensorless control strategy for the non-sinusoidal seven-phase PMSM, each sensorless control strategy will be highlighted in terms of robustness to the speed variation and torque ripple. Simulation results will be shown to verify the feasibility of the proposed methods.

This study is to deal with unwanted current harmonics in rotating (d-q) frames of a 7-phase non-sinusoidal permanent magnet synchronous machine (PMSM) in a wye-connected winding topology. The machine is supplied by a 7-leg voltage source inverter (VSI) fed by a DC-bus voltage. In control, cur-rent responses are expected to properly track their references. However, several unwanted harmonics of the non-sinusoidal back electromotive force (back-EMF) and the inverter nonlinearity generate unwanted harmonic com-ponents in d-q currents. These current harmonics cannot be nullified by con-trollers such as conventional proportional-integral (PI) controllers. Conse-quently, the current responses cannot track their references. In this study, a combination of conventional PI controllers and simple adaptive linear neu-rons (ADALINEs) is proposed to eliminate these current harmonics, improv-ing current control quality of the drive. The effectiveness of the proposed control structure is verified by experimental results.

The embedded energy conversion systems onboard vehicles impose strong constraints on power density (low weight and volume) and robustness. Several solutions can be used to achieve these objectives which consist in acting either on the design of the static converter or on the electric machine. In this paper, we propose to act on the two systems together. Thus, the increase in the power density of the converter will be achieved by using wide band-gap semiconductor power devices like the SiC or GaN. These components are very small and able to operate at high frequency, thus reducing the dimensions of passive components and of the cooling system used. To increase the reliability of the electric machine, a multiphase PMSM is used. In this paper, the proposed design method of the integrated GaN inverter into a machine is presented. It will be used for the realization of an integrated GaN inverter into a multiphase PMSM.

This study aims at eliminating unwanted harmonics in current control of a five-phase non-sinusoidal permanent magnet synchronous machine (PMSM) in an open-end winding configuration. The machine is supplied by two voltage source inverters (VSIs) using a single DC-bus voltage. High-frequency harmonics, caused by the zero-sequence current with the inverter switching frequency, have been significantly reduced by using a proper pulse width modulation (PWM) strategy. Meanwhile, low-frequency current harmonics are generated by unwanted harmonics of the back electromotive force (back-EMF) and by the inverter nonlinearity. In this study, the low-frequency current harmonics are nullified by simple adaptive linear neural networks (ADALINEs) in rotor reference frames combined with the back-EMF compensation. As a result, the quality of current control is improved. The effectiveness of the proposed strategies is verified by numerical results.

Torque density is usually improved by injecting the third current harmonic for five-phase permanent magnet synchronous machine (PMSM). It increases the degrees of freedom of a multiphase drive. However, it also separates the current limitations of the motor and the transistors, respectively related to the RMS and peak values of the currents. These two constraints are represented by Maximum Torque Per Ampere (MTPA) strategy and Maximum Torque Per Peak Current (MTPPC) strategy. In this paper, these two strategies are studied and analyzed in order to optimize the generated torque with injection of the third current harmonic. Torque improvement principal and the optimizing algorithm considering two constraints are illustrated. Then, the analytical results of these two strategies are compared and discussed. It is shown that injecting the third current harmonic can improve the torque especially at flux-weakening region. Besides, compared with MTPA, MTPPC could produce higher torque for the same inverter current limit.

Multiphase induction machines are advantageous regarding speed range extension in comparison with three-phase induction machines. This paper investigates how to choose the connection between stator phases for a multiphase induction machine allowing to extend the Torque-Speed characteristic of the machine, for traction application. A nineteen-phase induction machine with special phase connection is proposed. This topology is compared to a three-phase machine, with the same global volume, using a Finite-Element approach. The results show a significant extension of the Torque-Speed characteristic horizontally, by speed range extension, and vertically, by maximum torque enhancement, thanks to the pole-changing operation with the chosen phase connection.

This paper presents a simple method to size a concentrated winding permament magnet synchronous machine when a high number of slots is needed. A classical concentrated winding machine leads to a number of pole pairs close to the number of slots to be efficient. Thanks to a two slots pitches winding, number of slots can be doubled without deteriorate the winding factor. Moreover, this specific winding is also useful to deal with embarassing magnetomotive force harmonics. The method is detailed here for a specific case of a machine with integrated power converter. Sizing of the machine is also presented and finite element simulations results show performances of this design compared to a conventional one.

This paper presents new fault-tolerant control strategies for field-oriented control of 7-phase non-sinusoidal permanent magnet (PM) machines supplied by voltage source inverters (VSI). Single phase open-circuit fault is considered. The proposed strategies aim at finding waveforms of current references in natural frame in the way that post-fault currents create the same rotational magnetomotive force (MMF) as in healthy mode. Therefore, in the faulty mode, average torque can be maintained if no current limits are set. The proposed strategies are validated and compared to a previous strategy by numerical results in terms of joule losses, maximum RMS and peak phase currents, maximum phase voltage as well as their controllability with PI controllers.

This paper presents the modeling and control of an Electric Vehicle (EV) driven by a 5-phase Permanent Magnet Synchronous Machine (PMSM). The machine in an open-end winding configuration is supplied by two isolated 5-leg Voltage Source Inverters (VSIs). The inverters are fed by a Hybrid Energy Storage System (HESS) consisting of a battery and Supercapacitors (SCs). To increase the battery lifetime, the SCs are used to provide the high-power requirement during driving operations. In addition, an Energy Management Strategy (EMS) is proposed to take advantages of this EV architecture. Numerical results are derived to verify workability of the EV system.

Multiphase induction machines have the advantage of producing torque under different current harmonics. Theoretically, with some simplifications, the maximum produced torque can be considered proportional to the harmonic winding factor related to the injected current harmonic. However previous work has shown that this theoretical proportionality between the maximum developed torque and harmonic winding factors is not obtained in the case of a five-phase induction machine with eight-poles and fractional-slot tooth concentrated winding. This paper aims to investigate the effect of winding parameters, especially phase number, fundamental polarity and stator slots number, on the torque production in multiphase induction machine under harmonics injection. A comparative study is done between four five-phase winding configurations, with the same geometry and copper volume, under both first and third harmonic injection. Finally, a special 15-phase winding presenting better consistency between maximum developed torque and harmonic winding factors is proposed

For an open-end windings integrated Permanent Magnet Synchronous Machine, the demagnetization of the permanent magnets is analyzed when a transistor is shortcircuited and no specific control strategy is adopted. Depending on the temperature, the high currents due to the inverter fault may locally demagnetized the permanent magnets leading to an accelerated aging of the machine and torque loss. A cosimulation, using a Finite Element software for the machine coupled with an average modeling of the transistor, gives interesting local prediction of the machine behavior in healthy and degraded mode.

Compared to sinusoidal machines, a bi-harmonic machine (with only two harmonics of similar value in the electromotive force spectrum) can develop torque of comparable values under three kinds of supply: with only first or both first and third sinusoidal currents. Therefore, more degrees of freedom for the control of the machine can be achieved. In this paper, the specificities of 7-phase bi-harmonic permanent magnet synchronous machine (PMSM) are investigated under different control strategies, such as maximum torque per ampere (MTPA) at low speed and fluxweakening strategies at high speed, both in healthy and faulty operation modes. The fault with one open-circuited phase are taken into account. The current references are calculated in order to maximize the output torque under the constraint on both voltage and current. The performances of the considered machine is validated by numerical results.

This paper studies control strategies using modified transformation matrices when five-phase machines operate in oneopen-phase faults. The basic idea of these methods is to maintain the rotating field under asymmetrical conditions as the same as in healthy condition by determining new transformation matrices. The dimension of the new matrices is equal to the number of remaining healthy phases in post-fault conditions. There have been different ways to determine the new transformation matrices applied for different types of five-phase machines in recent decades. In this study, an overview and analyses on these methods will be presented. In addition, advantages and drawbacks of these control strategies are clarified by numerical results.

This article presents the development of an algorithm which can be used at standstill and low speed for sensorless control of a five-phase Permanent Manget Synchronous Machines (PMSM) with non-salient poles. The estimation method is based on the machine’s torque. Two different strategies are investigated for the proposed method. The first one uses the torque measurement and the second one uses the estimated torque from the measured currents. Results for the implementation of both strategies are presented and analysed, together with possible improvements to explore.

Even if intrinsically a five-phase machine can work with one opened phase, thermal constraints (temperatures in windings and Permanent Magnets) impose to decrease the mean torque in faulty operation mode. In order to elaborate optimum control which ensures safety and maximum torque, it is necessary to estimate in real-time the temperatures induced by the currents imposed in the remaining healthy windings of the machine. For a five-phase prototype, a multi-nodal thermal modelling which can take into account irregular losses and flow distribution has been developed. It is based on Electromagnetic FEM results for the losses and CFD calculation analysis. Results are presented in normal and faulty operation modes.

This paper presents a novel 7-phase hybrid excitation permanent magnet (HEPM) machine with three rotors around one stator. Two rotors with PMs axially magnetized and the third rotor with PMs radially magnetized. Thanks to the addition of the third rotor, the inactive end-windings in the configuration with two rotors are then becoming active with a contribution to the torque with an increase of 30%. The impact of the third rotor on the torque density and on the pulsating torques is presented. The fault-tolerant characteristics of the proposed machine are also presented, which proves the interests of this machine for low speed applications.

This paper analyses the copper losses due to the homopolar current of a five-phase open-end winding machine supplied by a 10-leg inverter and a single DC voltage source. This topology can have non-null high frequency homopolar current components that can increase the machine’s copper losses and result in overheating of the motor phase windings, a special concern for integrated drives. Accordingly, different modulation strategies are compared with the goal of reducing the homopolar current and, consequently the relative copper losses. The comparison study is achieved using Matlab/Simulink and a finite elements model in order to evaluate these losses.

The paper investigates the effect of the bar number on the performances of a five-phase squirrel-cage induction machine with fractional-slot tooth concentrated winding. With a same stator, five different rotor bar numbers are chosen and the rotor magnetic circuits are designed using an analytical approach. Then, a finite-element analysis is done under two different supply conditions: fundamental currents and third harmonic currents. Finally regarding the used winding specificities the possibility of second harmonic current supply is evaluated. The results are presented in a comparative way in order to determine the impact of rotor bar number on torque quality for the different supply modes.

This paper deals with control strategies when a seven-phase axial-flux brushless DC machine operates in one open-circuited phase fault by considering constraints on voltage and current. The constraints are related to the converter and machine design in terms of maximum values of voltage and current. In addition, the sensitivity of the torque control on parameters of new imposed current references under the base speed and in the flux-weakening region is analyzed. The current references taking into account only first and third harmonics in healthy phases are proposed to ensure the torque optimization while phase currents and voltages are within their limits. The usefulness of the control strategies and the parameter analyses are verified by numerical results.

Even if intrinsically a five-phase machine can work with one opened phase, thermal constraints (temperatures in windings and Permanent Magnets) impose to decrease the mean torque in faulty mode operation. In order to elaborate optimum control which ensures safety and maximum torque, it is necessary to estimate in real-time the temperatures induced by the currents imposed in the remaining healthy windings of the machine. For a five-phase prototype, a multi-nodal thermal modelling which can take into account irregular losses distribution has been developed. It is based on Electromagnetic FEM results for the losses and a thermal FEM analysis. Results are presented in normal and faulty operation modes.

A rotor position estimation for low speed and standstill applications in multiphase PMSMs with non-salient poles is presented in this paper. For this purpose, a comprehensive state of the art was performed. Then, an estimation method was proposed based on existing methods for surface three-phase PMSMs, and is finally adapted to a five-phase machine. Experimental results are illustrated and analysed.

Integrated Drives are a target in terms of simplicity in complex systems such as transportation. Anyway the integration of the power component inside the electrical machine induces challenges if the compactness is required. The CE2I project, for “Smart Integrated Drives”, searches to deal simultaneously with the constraints such as better thermal control and modelling, more efficient numerical virtual modelling for co-simulation, exploration of new materials and use of low losses, high frequency wide-band-gap (WBG) components.

This paper presents a comparative evaluation of fault tolerant control strategies for a five-phase Permanent Magnet Synchronous Machine (PMSM) under an opened-phase fault mode. Two main classical Fault Tolerant Control (FTC) methods and the no-reconfiguration strategy are compared with the normal mode operation considering peak current, peak voltage, average torque, torque ripples and measured temperatures of five windings of the five phases. The analysis of the temperature repartition shows that, in fault mode, at least in the particular studied case, the knowledge of the Joule losses is not sufficient for a correct control of the temperature.

In this paper we investigate the impact of the supply strategy on the peak voltage value for a five-phase bi-harmonic machine. In fact, this kind of machine is able to deliver significant equivalent torque from either the first, the third current harmonic due to the equivalent value of these harmonics in the back-emf. Since, different supply strategies are possible for this machine depending on the repartition of current between the two harmonics. Classically, the maximum torque per ampere strategy (MTPA) is used below the base speed, and it is achieved by setting a current in phase with the back-emf, with an optimal repartition of current density between the first and the third harmonic. However, it is not always possible practically to guarantee these features simultaneously, due to uncertainty in control. This uncertainty come out as a phase shift between back-emf and the current, or a modification in the optimal repartition of current density between the first and the third harmonic. Thus, this error can make the required voltage peak value more or less than the maximum voltage that can be delivered by the VSI. FE simulations and experimental are performed in order to test this phenomenon which can determine the sensitivity of the optimal control

This paper deals with the fault effects analysis and diagnosis in 6-Φ PMSM designed for aerospace applications. The addressed work aims to analyze the features offered by the space vector theory applied to these systems for fault detection and identification purposes. The paper starts with a presentation of the overall electric drive system structure and its control. Then, fault effects analysis under faulty operation mode of the 6-leg voltage source inverter is presented considering the space vector theory. Based on such analysis, an accurate FDI process is designed for these applications. All results are verified analytically and through simulation software using Matlab/Simulink

Multiphase machines have recently gained importance in the research community for their use in applications where high power density, wide speed range and fault-tolerant capabilities are needed. The optimal control of such drives requires to consider voltage and current constraints imposed by the power converter and the machine itself. If classical three-phase drives have been optimally controlled under such limits for a long time, the same cannot be said in the case of multiphase drives. This paper deals with this issue, where an optimal control technique based on Cascaded Model Predictive Controls (MPC) is presented for a five-phase permanent magnet synchronous machine (PMSM). A Continuous-Control-Set MPC (CCS-MPC) numerically computes optimal current references in real-time in order to exploit the maximum performance for given DC bus voltage and current limits. Then, a Finite-Control-Set MPC (FCS-MPC) is used to carry out the current control in the machine, directly applying the switching state that minimizes a cost function related to the current tracking. Obtained mixed microprocessor-based and FPGA-based real-time simulations prove the interest of the proposal, which ensures the optimal control of the multiphase drive operating under current and voltage constraints.

This paper addresses the design of a bi-harmonic five-phase Surface-mounted Permanent Magnet (SPM) machine for marine propulsion. The bi-harmonic characteristic results from the particular 20 slots-8 poles configuration that makes possible high value of third harmonic current injection. Thus the machine performance can be improved in terms of average torque, speed range, losses control and torque quality. As low ripple torques are wanted at low speed, the magnet layer is defined to reduce the cogging torque and to make third harmonic current injection increasing average torque and reducing pulsating torque in the same time. According to a selection procedure based on the numerical simulations of a high number of machines, it appears that designing the rotor with two identical radially magnetized magnet that cover two-third the pole arc allows to reach this goal. Referring to an equivalent three-phase machine, the torque ripple level of the bi-harmonic five-phase machine is more than three times lower. Furthermore the time simulations of the drives show a significant reduction of the speed oscillation, especially at low speed.

This papers presents a sensorless control for fivephase PM synchronous machines. An adaptive method, based on a linear neural network called Adaline (Adaptive Linear Neural Networks), has been achieved to estimate the rotor position with a high precision even at low speed without high frequency signal injection. Non-sinusoidal three-phase PM machines require more complex algorithm for sensorless control because of harmonics in the back-EMF. This is not the case for multiphase PM machines thanks to the property of equivalent machines in the eigenspace. Some given simulation and experimental results in laboratory confirm the possibility of real-time implementation of Adaline networks and the good performance of sensorless control based on this.

In this paper, the possibility of designing a fivephase Surface-mounted Permanent Machine (SPM) with 20 slots and 8 poles for a low power marine propulsion system is examined. Due to its particular winding and surface magnet design, the machine inherently offers an electronic pole changing effect from 3×4 pole pairs at low speed to 4 pole pairs at high speed. At high speed, in the constant power range, according to Finite Element Analysis, the Maximum Torque Per Ampere strategy appears not to be the right solution to minimize the whole machine losses (copper, iron and magnets). In particular, a strategy that favors the 4-pole rotating field at high speed allows to mitigate the magnet losses, thus limiting the risk of magnet overheating

The paper studies the impact of first and third current-harmonic repartition in a five-phase Permanent Magnet machine whose Electromotive Forces (emfs) have first and third harmonics of the same amplitude. With a five-phase machine, it is possible for the torque production to achieve independent controls of the first and third harmonics of currents by using a vector control in each one of the two characteristic orthogonal sub-spaces of the machine. The same torque quality as obtained with a three-phase machine with sinusoidal emf can be thus obtained with a non-sinusoidal emf and with one more supplementary degree of freedom for the control. Based on the Maximum Torque Per Ampere (MTPA) strategy used for three-phase machines, a comparison of the obtained torque/speed characteristics of the machine is achieved using either one or two harmonics. The voltage limits imposed by the Voltage Source Inverter and two different values of the maximum allowed current densities are taken into account for obtaining the optimum repartition between first and third harmonics of currents: it appears that at first, from the point of view of efficiency, the MTPA is not optimal except for low speeds and secondly that the repartition of currents is not trivial and depends for example on the considered maximum current densities.

This paper deals with the real time Fault Detection and Identification (FDI) process of inverter Open Switch Fault (OSF) and Open Phase Fault (OPF) in five-phase PMSM designed for aerospace applications in which the electric drive system has particular operating characteristics either in healthy states or in the faulty ones. Two original contributions are considered in this paper. They consist in normalizing the input variables of the FDI process applied to multiphase system and compensating the noise (switching and sensors noises) and dc-component resulting from the fault occurrence. The proposed strategy uses multiple normalized criterias derived from the measured phase currents and the voltages obtained from the outputs of the current controllers. The FDI shows an independence with respect to the transient states and to the switching and measurement noises. Moreover, it can be easily included in an existing software without any additional sensors. The validity of the proposed method is verified by Matlab/Simulink simulation tests.

This paper describes analytical and simulation tools to analyze the effects of Open Switch Fault (OSF) and Open Phase Fault (OPF) on five-phase PMSM designed for aerospace applications. For such applications, the fault tolerance and the reliability of the drive (PMSM and the power converter) are important to take into account for design. The addressed work aims essentially to analyze the dynamic of the measured phase currents in post-fault operation with a real-time fault diagnostic purpose in the VSI. The paper starts with a presentation of the electric drive system structure and its control used in pre-fault and post-fault operation. Then, fault effects analysis (FEA) on the system will be considered. All results are verified analytically and through simulation software using Matlab/Simulink®. The theoretical development and the simulation results show that the five-phase PMSM under inverter faults presents typical characteristics which can be used as better input variables for designing a high performance real-time fault diagnostic and classification process

This paper analyzes two dual-motor fault-tolerant topologies. The first one supplies independently both machines while the second one connects them in series for reducing the number of transistors. For a given DC-link voltage, the converter component sizing is based on the peak current obtained in the normal and degraded modes.

This paper analyzes two dual-motor fault-tolerant topologies for aerospace thruster application.The first structure supplies independently both machines whilethe second one connects them in seriesfor reducing the number of transistors and offering a capability of energy management between the sources. Inverter short-circuit fault isconsidered.Based on the peak-currents obtained in simulation in degraded mode without reconfiguration and with two different reconfiguration strategies, the two proposed topologies can be compared in economic and technical aspects.

An original analytical expression is presented in this paper to obtain optimal currents minimizing the copper losses of a multi-phase Permanent Magnet Synchronous Motor (PMSM) under fault conditions. Based on the existing solutions [i]opt1 (without zero sequence of current constraint) and [i]opt2 (with zero sequence constraint), this new expression of currents [i]opt3 is obtained by means of a geometrical representation and can be applied to open-circuit, defect of current regulation, current saturation and machine phase short-circuit fault. Simulation results are presented to validate the proposed approach.

Multiphase machines are widely used in electric marine propulsion especially because of their fault-tolerance which allows to guarantee the propulsion even if a fault occurs in the electrical system. In addition, the 12 slots/8 poles three-phase machine (12/8/3 machine) with fractional slot concentrated windings is known for its low level Permanent Magnet eddy currents losses, making it adequate for compact high speeds applications. Since this interesting property is due to a 0.5 value for the number of slots per pole and per phase (spp=0.5), then the paper examines a five-phase 20 slots/8poles fault tolerant machine whose spp=0.5. Using an analytical model, the copper losses and an estimation of the magnet losses for the two machines are presented and a comparison is done between the two machines.

In this paper, the study of torque/speed characteristic for five-phase Surface-mounted Permanent Magnet (SPM) machine is carried out. With considering several hypothesis (linear magnetic modelling, only first and third harmonic terms in the back-emf and current spectrums), an optimization problem that aims to maximize the torque for given maximum voltage and RMS current is formulated: the optimal torque sharing among the two virtual machines (the two dq-axis subspaces) that represent the real five-phase machine is thus calculated for any mechanical speed. For an inverter and a DC voltage sized with only considering the first harmonic of back-emf and current, the problem is solved with changing the ratio between the two virtual machine back-emfs and changing the ratio between the two virtual machine inductances. The results are examined by introducing particular speed points.

The major drawback of usual dual three-phase AC machines, when supplied by a Voltage Source Inverter (VSI), is the occurrence of extra harmonic currents which circulate in the stator windings causing additional losses and constraints on the power component. This paper compares dedicated Pulse Width Modulation (PWM) strategies used for controlling a dual three-phase Permanent Magnet Synchronous machine supplied by a six-leg VSI. Since the application is intended for low-voltage (48V) mild-hybrid automotive traction, an additional major constraint arises: the compactness of the drive related to the size of the DC-bus capacitor. Thus, the PWM strategy must be chosen by taking into consideration its impact on both, the motor and the RMS value of DC-bus current

Multi-phase machines are known for their fault-tolerant capability. However, star-connected machines have no fault tolerance to inverter switch short-circuit fault. This paper investigates the fault-tolerant operation of an open-end five-phase drive, i.e. a multi-phase machine fed with a dual-inverter supply. Open-circuit faults and inverter switch short-circuit faults are considered and handled with various degrees of reconfiguration. Theoretical developments and experimental results validate the proposed strategies.

This paper presents a specific control strategy of double-ended inverter system for wide-speed range of open-winding five phase PM machines. Different virtual stator winding configurations (star, pentagon, and pentacle) can be obtained by choosing the appropriated switching sequences of two inverters. The motor’s speed range is thus increased.

Development of new ways to provide clean onboard electric energy is a key feature for the sailing boat industry and sail race teams. This is why marine turbines (MT), are considered to provide onboard energy. These turbines can be used to harness kinetic energy of the water flow related to the ship motion. In this paper we propose to study an unconventional design of such a turbine where the electrical generator is located in the periphery of the blades and where the magnetic gap is water filled. This kind of solution called “RIM DRIVEN” structure allows to increase the compactness and the robustness of the system. Due to the strong interaction of the multi physical phenomena, an electromagnetic model and a thermal model of the PM generator are associated with a hydrodynamic model of the blades and of the water flow in the underwater air gap. These models are used in a global coupled design approach in order to optimize, under constraints, the global efficiency of the system. This solution allows to optimize the system design.

this paper studies magnet eddy-current losses in permanent magnet (PM) machines with concentrated winding. First of all, space harmonics of magnetomotive force (MMF) and their influence on magnet losses in electrical machines are investigated. Secondly, analytical model of magnet volume losses is developed by studying the interaction between MMF harmonics wavelengths and magnet pole dimensions. Different cases of this interaction are studied according to the ratio between each harmonic wavelength and magnet pole width (following flux density variation). Then various losses sub-models are deduced. Finally, using this analytical model, magnet volume losses for many slots/poles combinations of 3, 5, and 7 phase machines with concentrated winding are compared. This comparison leads to classify combinations into different families depending on their magnet losses level. Besides, in order to validate the theoretical study, Finite Element models are built and simulation results are compared with analytical calculations.

This paper presents multiphase permanent magnet machines with concentrated non-overlapped winding as a good candidate for automotive low voltage mild-hybrid applications. These machines often require a trade-off between low speed performances such as high torque density and high speed performances like flux weakening capabilities. This paper describes how to choose a key design parameter to ease this compromise, the slots/poles combination, according to three parameters: winding factor including harmonics factor, rotor losses amount thanks to a comparison factor, and radial forces balancing. The comparison criterions are based on both analytical formula and Finite Element Analysis

In order to get a low cost mild hybrid system, a global objective is to keep the actual thermal engine architecture as in Figure 1. As consequence, the current clawpole synchronous automotive generator must be replaced by a new more powerful electrical machine but with the same large speed range [0 -18000 rpm]. In the project, a power of 15 kW and a DC bus voltage of 60V have been chosen to provide a regenerative breaking at minimum cost. With this payload (250A for the DC bus current), a five-phase machine appears to be interesting because MOSFET transistors of the voltage source inverter (VSI) have not to be used in parallel configuration (only two rated 150A transistors per leg for the VSI). As the speed range is large, a flux weakening must be applied. As the five-phase drives [16] have more degrees of freedom than three-phase ones [13], different flux weakening strategies can be considered. The aim of this paper is to compare one of them.

This paper deals with on-line software fault detection and isolation method for a drive composed of a fourleg inverter and a three-phase permanent magnet synchronous machine. The considered faults are single-phase open-circuit and current sensor outage. The method is based on the monitoring of the abc currents with phase-locked loops and the `CUSUM’ algorithm for the decision system. The impact of the considered faults is examined: first, in case there is no modification of the control and then in case a control reconfiguration is performed taking into account the fault diagnosis. Closed-loop operation is performed before, during and after the fault. Experimental results show that the latter case allows maintaining the drive in safe operation.

This paper investigates the influence of the rotor structure on torque and Flux weakening region of V-shape IPM machine from TOYOTA PRIUS type, more specifically, keeping always the same magnet volume, we study the effect of the open angle between the two magnet segments of each V-shape pole on the machine performance. Moreover, in order to examine the impact of phase number on the machine characteristics, PRIUS structure is transformed into 5-phase machine of the same type and dimensions. As well, an optimization procedure is carried out to determine the optimal open angle according to main characteristics. The previous investigation is done by using a free Finite Elements Methods (FEM) program coupled with another optimization program. Using this obtained methodology the study analyzes for 3-phase and 5-phase machine the average and pulsation of torque, cogging torque, phase back-EMF, constant power operating capability

Four French Grandes Écoles (Engineering and Business Schools) of PARISTECH open in October 2010 an education program which main objective is the impact study of the massive insertion of electrical energy in autonomous vehicles. The program with a common core curriculum and two different options is described.

In this paper, an original multi-phase Surface Mounted Permanent Magnet (SMPM) Machine designed for naval propulsion is proposed. The design objective of this high power low speed machine is twofold: to enhance the fault tolerance capability of the system and to optimize the quality of the torque by reducing the electromagnetic torque ripples which underlie the acoustic behaviour of the motor and of the global mechanical structure. A low level of ripple torques must also be ensured in faulty operations. To fullfill these constraints, the machine is equipped with a fractional-slot concentrated winding made up of four 3-phase windings each one being star-connected, each star being magnetically shifted by an angle of 15 degrees. This 4-star 3-phase configuration allows to reduce the cogging torque and to separate magnetically and physically the phase windings. The end-turns are also drastically reduced, which improves the compactness and the efficiency of the machine. This original multi-phase machine is supplied by four 3-phase PWM voltage source inverter with sinusoidal current law. The magnetic independences between the four star windings allow a very simple control of the four-star supply and a straightforward fault operating mode. Moreover, this 4-star winding configuration yields to very low torque ripples in nominal configuration (four stars connected) and in faulty operations if two magnetic non adjacent stars are disconnected. For all these reasons, this structure appears particularly suitable for naval propulsion application since it increases the machine performances in terms of compactness, reliability and quality of torque.

This paper deals with an on-line fault detection method for multi-phase PMSM drives. The method is based on the detection of the stator current positive- and negativesequence fundamental components expressed in the stationary reference frame. These components allow calculating a fault index used for the detection of stator faults, such as open-circuit faults. The decision criterion is based on the CUSUM algorithm. A model of a five-phase machine with one single-phase opencircuit is derived and validated with experimental results. Then, it is shown that the proposed method achieves fault detection on a wide speed range and even during speed transient.

For Electric Vehicles (EV), the charger is one of the main technical and economical weaknesses. This paper focuses on an original electric drive [1]-[3] dedicated to the vehicle traction and configurable as a battery charger without need of additional components. This cheap solution can outfit either electric or plug-in hybrid automotive vehicles, without needing additional mass and volume dedicated to the charger. Moreover, it allows a high charging power, for short duration charge cycles. However, this solution needs specific cares concerning the electrical machine control. This paper deals with the control of this drive [1], focusing on traction mode. In introduction, a review is done about topologies of combined on-board chargers. Then, the studied topology is introduced; using a 3-phase brushless machine supplied with a 6-leg Voltage Source Inverter (VSI). A model for its control is defined in the generalized Concordia frame, considering the traction mode. Then, an analysis of this model is established using a multimachine theory and a graphical formalism (the Energetic Macroscopic Representation denoted EMR). Using EMR, a description of energy flows shows specific control constraints. Indeed, numerical simulations illustrate the perturbations on the currents and the torque when controlling the machine with standard control methodologies. An improved control, deduced from the previous analysis, shows good performances, strongly reducing currents and torque ripples. Keywords- Electric Vehicle, Plug-in Hybrid Vehicle, On-board Battery Charger, H-bridge Voltage Source Inverter, Multiphase Drive, Control

This paper proposes an auto-adaptive current control that makes possible to reduce torque ripples of multi-phase machines in open-circuited phase conditions. Contrary to existing methods, current references are not recomputed and the control scheme used in normal mode is auto-adapted in order to run the machine with open-circuited phases. The number of degrees of freedom of the control scheme is adapted to the number of degrees of freedom of the drive and current controllers are auto-adaptive in order to reject the induced speed-dependent harmonic voltage disturbances that appear in fault-mode. Experimental results are presented to show the effectiveness of the proposed method.

This paper proposes a simple way to control multi-phase drives in open-phase conditions. Contrary to existing methods, current references are not recomputed and the control scheme is kept the same to run in open-circuited phase condition. In order to work in fault-conditions, the number of degrees of freedom of the control scheme is adapted to the number of degrees of freedom of the drive. Since a particular attention has to be dedicated to the structure and controller tuning, harmonic content of induced perturbations in fault mode is exhibited. Simulation and experimental results are presented to show the effectiveness and the limitations of the proposed method.

This paper deals with the generation of optimal current references for Multi-phase Permanent Magnet Machines with open-circuited phases. Compared to classical methods, the use of a vectorial approach makes it possible to generate optimal current references, from a copper losses point of view, on-line. This method is viable whatever the number of open-circuited phases. As an example, a five-phase machine is experimentally controlled.

This paper deals with the identification of a new high power starter-alternator system, using both: a Finite Element Method (FEM) modeling and an elementary experimental vector control. The drive is composed of a synchronous 7-phase claw-pole machine supplied with a low voltage / high current Voltage Source Inverter (VSI). This structure needs specific approaches to plan its electrical and mechanical behaviors and to identify the parameters needed for control purpose. At first, a Finite Element Method (FEM) modeling of the machine is presented. It is used for the predetermination of the electromotive forces and of the torque. Experimental results are in good accordance with numerical results. In a second part, resistive and inductive parameters of the drive are determined by an original experimental approach that takes into account each component of the drive: the battery, the VSI and the machine.

This paper deals with the modeling and the control of a new high power 12V starter-alternator system. The drive is composed of a 7-phase synchronous claw-pole machine with separate excitation, supplied with a 7-leg Voltage Source Inverter (VSI) designed for low voltage and high current. The system is modeled in a generalized Concordia frame and a graphical description is used to highlight energetic properties of such a complex system. A control scheme is then deduced from this graphical description. Two controls are achieved in generator mode: one is using the VSI in a square-wave mode, the other in a Pulse Width Modulation (PWM) mode. Experimental results are provided.

This paper presents an analytical multi-physic modeling tool for the design optimization of a new kind of naval propulsion system. This innovative technology consists in an electrical permanent magnet motor that is integrated into a duct and surrounds a propeller. Compared with more conventional systems such as pods, the electrical machine and the propeller have the same diameter. Thus, their geometries, in addition to speed and torque, are closely related and a multidisciplinary design approach is relevant. Two disciplines are considered in this analytical model: electromagnetism and hydrodynamics. An example of systematic design for a typical application (a rim-driven thruster for a patrol boat) is then presented for a set of different design objectives (efficiency, mass, etc). The effects of each model are commented.

This paper focuses on an experimental method to determine the electric parameters of a seven-phase low-voltage multiphase drive. The drive is a belt driven starter-alternator for powerful cars with Hybrid Electrical Vehicles (HEV) functions. The resistive and inductive parameters are necessary to obtain the six characteristic time constants of the control modeling. Classical direct measurements lead to imprecise results because of very low values for the windings electric resistance and inductance. Effects of the imprecision on the measurements are all the more important that time constants are obtained by a ratio of cyclic inductances by resistance, with cyclic inductances being a linear combination of seven measured inductances. The methodology for identification detailed in this paper is based on a stator current vector control, in a multi-reference frame. This methodology allows us to get directly these time constants. Numerous measurements allow the robustness of the method to be evaluated.

This paper is included into the theme “challenges for marine renewable energy”. It discusses an innovative concept of electrical machine that should be particularly fitted to marine current turbine generators. Our investigations focus on permanent magnet direct-driven synchronous generators connected to a variable speed power electronic drive. Original and conventional solutions are compared in terms of mass and cost for a common set of specifications of a realistic application.

In the context of high power low-voltage applications as starter-generator for automotive, multi-phase drives present the attractive characteristic of reducing the current per phase and per leg. A 5- or 7-phase machine is also more suitable for using concentrated windings, attractive for their short end-windings and subsequently for a higher expected torque-to-volume density. In this perspective, the 5- and 7-leg Voltage Source Inverters (VSI) are compared with the 3-leg VSI. In the first part, for the same set of resistances and inductances coupled in different wye-coupling configurations, we examined the DC-bus currents and the power recovered by the load for a square-wave VSI control: the 7-leg VSI is the more efficient because it makes best use of the harmonics. In the second part, the torque ripples of 3-, 5- and 7-phase drives are compared: the 7-phase drive torque ripples are the lowest ones because of the less sensitivity to the harmonics of the currents. In the last part, a Pulse Width Modulation control is studied, with almost the same voltage harmonics amount as this one obtained with the square-wave mode control. Experimental results are given for the 7-leg VSI either with a passive load or with a 7-phase permanent magnet synchronous motor.

More and more electrical systems need a high level of reliability. Among the potential solutions, multi-phase machines take a particular place to improve the reliability of AC drives. Efficient current controls lead to the use of the multiple d-q spaces concept. When one or several phases are short or open-circuited, ripples appearing in the d-q currents require a particular attention. Many authors have proposed a new model of the machine taking into account these asymmetrical connections. These models have made it possible to deduce efficient current controls. However, a new model is built for each new case. For machines with a high number of phases, this technique becomes rapidly cumbersome and time consuming. Moreover, some authors use the derivative operation to model voltages across open-circuited phases which can lead to problems of convergence, stability and long simulation time when using numerical simulations. This paper proposes a simple and easy-to-implement way of integral modelling which makes it possible to achieve numerical simulations of multi-phase drives under fault conditions with keeping the original model of the drive. Experimental measurements on a seven-leg seven-phase drive show the effectiveness of the proposed solution.

This paper deals with fault tolerant multiphase electrical drives. The quality of the torque of vector-controlled Permanent Magnet (PM) Synchronous Machine supplied by a multi-leg Voltage Source Inverter (VSI) is examined in normal operation and when one or two phases are open-circuited. It is then deduced that a seven-phase machine is a good compromise allowing high torque-to-volume density and easy control with smooth torque in fault operation. Experimental results confirm the predicted characteristics.

This paper deals with control in fault operation of a seven-phase Permanent Magnet Synchronous Machine supplied by a seven-leg Voltage Source Inverter (VSI). Using a Multi-Machine description, a seven-phase machine which presents a special ability to be controlled with only five phases supplied has been designed. The machine is presented and experimental results are provided when two phases are opened. In a first case of no change of classical control, high torque ripples are observed. In a second case, a specific control deduced from the Multi-Machine modelling is suggested for reducing torque ripples.

This paper deals with control in fault operation of a seven-phase Axial Flux Permanent Magnet (AFPM) supplied by a seven-leg Voltage Source Inverter (VSI). We present a seven-phase machine that has been designed with a special ability to be controlled with only five phases supplied. Experimental results are provided when two phases are opened in two cases. In the first case, the vector control is not changed when two phases are opened: high torque ripples are then observed. In the second case, a specific control allows to reduce the torque ripples.

A fault-tolerant seven-phase axial-flux permanent magnet (AFPM) machine with a soft magnetic composite (SMC) stator has been designed thanks to analytical and 3D finite element method. In this paper, we present its characteristics and show that a high number of phases allows to get a good quality of the torque with a design simpler than this one of the three-phase AFPM machines. Experimental back-electromotive forces (back-EMF) and the cogging torque are then compared with predeterminations. Finally, experimental torque of a drive composed of a seven-leg Voltage Source Inverter (VSI) supplying the machine in a vector control is presented.

Chania (Crete Island, Greece)

For the experimental seven-phase machine studied in this paper, parameters necessary for the control such as inductances and electromotive force (EMF) are sensitive to harmonics. A conventional analytical method in which only the first harmonic is taken into account does not give good results. Besides, the machine is an axial-flux one and has two asymmetrical rotors: a 3D-FEM is then necessary. Comparisons between predeterminations and experimental results show sufficient accuracy to achieve a control model.

This paper deals with modeling and control of a three-phase permanent magnet synchronous machine (PMSM) with sinusoidal back electromotive forces (emf) under supply fault conditions. The overall system is modeled thanks to the Energetic Macroscopic Representation (EMR) formalism considering that a fusible element opens the phase circuit. Using systematic inversion rules of the EMR, a Maximum Control Structure (MCS) is deduced. Based on the analysis of degrees of freedom (DOF) of the drive, two control strategies for constant-torque under supply fault conditions are inferred. One method balances generated perturbations caused by the supply fault and the other one consists in modifying current controller’s structure. These methods are validated through simulations with Matlab software.

Dresden , Germany, 11-14 september 2005, CD-ROM.

This paper deals with design constraints of a 7-phase Permanent Magnet Synchronous Machine (PMSM) supplied by a 7-leg Voltage Source Inverter. The optimum back electromotive force waveform is determined in order to get maximum torque for a given DC bus voltage.

IAS 2004, IEEE Industrial Application Society Annual Meeting, Seattle, Washington October 3-7, 2004, CD-ROM

The traction system of the subway VAL 206 is ensured by DC machines connected in series. A common chopper supplies the armature windings and a double-chopper supplies the field windings. Another power structure is suggested in order to increase performances during losses of adhesion. A specific control strategy is defined in order to obtain different torque on both machines despite their common armature current. An anti-slip control can thus be developed in applying the desired torque to each bogie at just the right time. This torque tracking strategy is validated on a 1.5 kW experimental set-up.

PESC 2004, IEEE Power Electronics Specialists Conference, Aachen, Germany in June 20 - 25, 2004,CD-ROM.

This paper proposes a sensorless control based on Sliding Mode Observer (SMO) for a Five-phase Interior Permanent Magnet Synchronous Machine (FIPMSM), with a consideration of the third harmonic component. Compared to the conventional three-phase machines, the third harmonic of electromotive force contains more information. Thus, in this paper, we consider the first and third harmonic components of the five-phase machine to estimate the rotor position that is necessary for the control. Simulation results of the implemented SMO are shown to verify the feasibility of the proposed sensorless control strategy

Dans le cadre d’une commande en mode dégradé d’un drive comprenant deux machines polyphasées connectées en série et pilotées de façon indépendantes, l’article s’intéresse à analyser la performance du drive dans le cas d’une reconfiguration complète, c’est-à-dire, une modification de l’algorithme de commande lors d’un défaut en mode dégradé

Les systèmes de propulsion automobile ou navale nécessitent des entraînements électromécaniques compacts. Lorsque le diamètre alloué à la machine est faible, la mise en œuvre d’une solution à grand nombre de pôles est difficile, ce qui interdit l’entraînement direct. Concevoir une machine intrinsèquement apte à fonctionner tant en basse vitesse qu’à haute vitesse permettrait de supprimer le réducteur mécanique généralement mis en œuvre. Dans le cadre de cette problématique, cet article analyse les propriétés d’une machine synchrone pentaphasée à aimants déposées équipée d’un bobinage concentré générant à la fois p paires et 3p paires de pôles. Conçue pour être pilotée en commutation électronique de pôles, cette machine à cinq phases, équivalente à un ensemble de deux machines diphasées équivalentes (de type machine dq), présente la particularité suivante : les deux machines diphasées décrivant son comportement électromagnétique ont la même constante de temps et tout particulièrement des amplitudes comparables de la force électromotrice.

Dans le domaine des systèmes embarqués (avionique, marine, automobile), l’emploi d’entrainements électriques permet d’optimiser le rendement énergétique du système en apportant plus de souplesse dans la gestion énergétique. Une des facettes du rendement global d’un système est son taux de disponibilité que ce soit dans les systèmes de transport ou ceux de production de l’énergie à partir de sources renouvelable. Or, l’environnement des systèmes embarqués est souvent difficile (températures extrêmes, humidité,…). De ce fait, les entrainements électriques se doivent donc de présenter une aptitude la tolérance aux pannes : on cherche en fonctionnement dégradé à conserver la fonctionnalité de conversion électromécanique même si la puissance est réduire. De ce fait, les entrainements électriques polyphasés, naturellement à tolérance de pannes, font l’objet de nombreuses investigations tant du point de vue de la conception que de la commande, notamment en mode dégradé lorsqu’une ou plusieurs phases ne sont plus alimentées. Munis de contrôles vectoriels, ces entraînements nécessitent la présence de capteur de position (codeur optique ou synchro-résolver). L’objet du papier est de proposer une estimation de la position θ qui pourra se substituer à celle du capteur en cas de panne de celui-ci. Le contrôle vectoriel dans le repère de Park pourra ainsi être conservé. Dans le cas des entraînements triphasés de très nombreuses méthodes ont été proposées par contre très peu d’études existent sur les machines polyphasées. L’originalité de la méthode proposée repose sur l’exploitation de caractéristiques harmoniques particulières des machines polyphasées par rapport aux machines triphasées. En triphasé, l’harmonique de rang trois de force électromotrice d’une machine synchrone à p paires de pôles est utilisé, dans certaines méthodes sans capteur pour estimer les instants de commutation d’une commande en trapèze. Pour une machine à 5 phases vérifiant certaines hypothèses en termes de contenu spectral de force électromotrice, il est possible, non seulement de déterminer ces mêmes instants de commutation pour une commande trapèze, mais de plus d’estimer la position réelle θ, nécessaire pour réaliser la transformée de Park en commande vectorielle. Il est en effet possible dans ce cas d’obtenir non seulement comme en triphasé sin(3pθ), mais également cos (3pθ) et sin(5pθ) : ces trois grandeurs permettent de déterminer sans équivoque θ alors que sin(3pθ) donne au mieux pθ à 120° près.

Dans un contexte particulièrement favorable au développement des énergies renouvelables, les travaux présentés concernent la conception d’une génératrice hydrolienne innovante pour la récupération de l’énergie des courants de marée. La génératrice, couplée à une hélice à axe horizontal conçue pour la récupération de l’énergie des courants, est une machine synchrone à aimants permanents et à entraînement direct. L’originalité réside dans la structure même de l’hydrolienne, inspirée directement de nouveaux systèmes de propulsion navale, où le rotor et le stator sont placés en périphérie de l’hélice et protégés par une tuyère. De fait, le diamètre de la machine, ainsi que son couple et sa vitesse de rotation, sont essentiellement dictés par des considérations hydrodynamiques. Il en résulte des machines électriques originales de forme annulaire: grand diamètre, grand nombre de pôles et très courtes axialement. Leur forme est assez proche de celles des machines dites « roue », bien que ces dernières soient plus longues et leur dimensionnement plutôt dicté par des considérations mécaniques. Ainsi, leur dimensionnement doit prendre en compte certaines spécificités dont l’une d’entre elles est la proportion des fuites magnétiques dans le sens axial. Généralement négligées, à juste titre, pour des machines ayant des proportions classiques, il devient important de prendre en compte leurs effets pour des machines ayant un ratio entrefer / longueur axiale anormalement élevé. Cet article propose des modèles analytiques simples, appuyés par des simulations par éléments finis 3D, permettant un calcul plus réaliste de la force électromotrice à vide et de l’inductance synchrone de ces machines particulières. Ils seront particulièrement adaptés à des travaux de pré dimensionnement systématique (optimisation) nécessitant un ensemble d’outils simples, robustes et de bonne précision.

Les machines synchrones à aimants permanents de grand diamètre et basse vitesse sont utilisées dans un nombre croissant d’applications. On les retrouve dans le domaine éolien de forte puissance, mais également dans la propulsion navale, où se développent des solutions à entraînement circonférentiel, ou encore la récupération d’énergie hydrocinétique (hydroliennes). Afin d’évaluer les performances de ces machines, il est souvent intéressant de disposer d’outils analytiques simples qui permettent des calculs rapides mais satisfaisants dans une approche de dimensionnement du premier ordre. Ces formulations simplifiées sont généralement suffisantes lorsqu’elles sont bien adaptées à la structure étudiée. Par contre, elles tendent à perdre en précision lorsque les dimensions deviennent inhabituelles, par exemple pour des nombre élevés de pôles. Cet article propose des formulations adaptées à ces structures particulières en prenant en compte, notamment, les fuites inter-aimant habituellement négligées. Les modèles proposés sont validés par des calculs numériques par différences finies 2D sur des applications concrètes.

Cet article s’intéresse à la conception des machines synchrones polyphasées à aimants déposés alimentées par onduleur de tension à Modulation de Largeurs d’Implusions (MLI). Ce type de machine permet de répondre à des cahiers des charges exigeants en terme de compacité, de comportement vibratoire et de tolérance aux pannes. En utilisant la décomposition multimachine, la conception d’une machine polyphasée peut s’aborder comme la conception de plusieurs machines fictives composant la machine polyphasée. L’adaptation de la machine polyphasée à son onduleur et l’amélioration de ses performances en terme de couple se traduit par la recherche de bobinage spécifiques. Ces bobinages doivent orienter le contenu de la force magnétomotrice statorique pour égaliser les constantes de temps des différentes machines fictives et filtrer correctement l’induction rotorique. L’intérêt de cette démarche de conception est illustrée par l’étude d’un petit propulseur en nacelle. On considère la structure initiale triphasée comportant 60 encoches et 14 pôles et on s’autorise uniquement une modification du bobinage. Un bobinage pentaphasé est déterminé : il permet de réduire les pertes Joule de 4% et d’atténuer les pulsations de couple de 94%. Si la stratégie de commande multimachine est mise en oeuvre, alors le couple moyen peut être augmenté de 11% à pertes Joule données par rapport à la solution triphasée.

This paper investigates the influence of the rotor structure on torque and Flux weakening region of V-shape IPM machine from TOYOTA PRIUS type, more specifically, keeping always the same magnet volume, we study the effect of the open angle between the two magnet segments of each V-shape pole on the machine performance. Moreover, in order to examine the impact of phase number on the machine characteristics, PRIUS structure is transformed into 5-phase machine of the same type and dimensions. As well, an optimization procedure is carried out to determine the optimal open angle according to main characteristics. The previous investigation is done by using a free Finite Elements Methods (FEM) program coupled with another optimization program. Using this obtained methodology the study analyzes for 3-phase and 5-phase machine the average and pulsation of torque, cogging torque, phase back-EMF, constant power operating capability.

L’objectif du brevet est de proposer une topologie de machine permettant de solutionner ce type de défis avec un focus sur des machines sans refroidissement par circulation par pompe de fluide liquide. L’intégration de l’électronique de puissance dans les machines posent les défis suivants :  Thermique à savoir la compatibilité concernant les différents composants présents à l’intérieur de la machine intégrée : le passage « actuel » aux composants de puissance Grand Gap supportant normalement des températures plus élevées que les composants Si et plus compatibles à celles que supporte la machine doit permettre l’intégration sans diminution des performances de la machine seule. A noter qu’il ne faut pas oublier les composants petits signal pour les contraintes en température  Compatibilité électromagnétique : s’il n’y a moins de problème de compatibilité électromagnétique à l’extérieur (uniquement deux fils parcourus par courant continu) , les contraintes se retrouvent à l’intérieur de la machine  Fiabilité fonctionnelle du drive du fait de l’augmentation de la complexité structurelle du drive électrique avec des contraintes thermiques et électromagnétiques

The present invention relates to a method for controlling an inverter device having six branches (B1...B6) supplying power to a double three-phase machine (3) comprising three first windings (R, S, T) and three second windings (U, V, W), one first winding (R, S, T) being respectively adjacent to a second winding (U, V, W), the method comprising the following steps: - the commands to be applied to the branches of the inverter device are determined as a function of the desired operating point for the machine (3) by a pulse width modulation in which the pulses applied to the different branches are temporally centred relative to one another, - from the determined commands, the commands for allowing at least one branch (B1, B2, B3, B4, B4, B5, B6) to be blocked are determined by varying, proportional to the pulse widths, the commands associated with the three first windings (R, S, T) and to the three second windings (U, V, W), - selecting the combinations of commands allowing two adjacent branches to be blocked, - and applying one of the selected combinations.

The two polyphase motor control device comprises a first and a second six-phase motors (MH1, MH2) to six parts corresponding to six phases uniformly spatially distributed, interconnected in series, and said series interconnection of two six-phase motors (MH1, MH2) comprising two to two connections of successive respective branches of the two six-phase motors (MH1, MH2), said connections being alternately in phase and in phase opposition.

The invention mainly relates to a polyphase rotary electrical machine with at least five phases including a rotor comprising a plurality of main poles of alternating polarity and a stator of said rotor separated by an air gap, characterized in that it comprises a control system ( 35) comprising, for each phase, a control system (35A-35E) adapted to determine a first (I1r.A-I1r.E) and a third (3R. AI3r.E) Set current harmonics whose effective values depend on effective value of a current (effective I) browsing machine and a report, the report depending on a ratio of a maximum amplitude of a first and a third harmonic electromotive force of the electric machine, so as to maximize an electromagnetic torque produced by the electrical machine

The invention relates to a synchronous polyphase rotary electrical machine, comprising a rotor (4) having poles (12) rotating within a stator having notches (8) defining the teeth around which coils are wound of stator (20, 22, 24, 26), wherein the ratio (SPP) obtained by dividing the number of slots (8) by the number of phases of the machine and the number of rotor poles is equal to 2/7 .

The rotary drive system comprises: - a DC voltage source (102) - An electric motor (104) having an axis of rotation (A), and having independent phases (a, b, c) having directions around the axis of rotation (A) - An inverter (106) for connecting each phase (a, b, c) to the DC voltage source (102) and - a control device (110) for providing a command to the inverter (106). The control device (110) comprises: - means (118) for selecting the formula, for selecting a formula from predetermined formulas, each predetermined formula being adapted to calculate an homopolar voltage set point or a zero sequence current setpoint - Means (124) set point determination, for applying the selected formula to determine, according to the selected formula, a zero sequence voltage set point or a zero sequence current setpoint, and - the means (126) for controlling the determining , for determining the order of the inverter (106) from the determined set.

Le transport de l’énergie électrique par des réseaux triphasés a conduit par le passé au développement de convertisseurs électromécaniques triphasés. Ces derniers ont bénéficié de l’essor des interrupteurs de puissance et de celui des composants de commande type Digital Signal Processor (DSP). Les performances de ces classiques machines électriques triphasées associées à des onduleurs s’en sont trouvées accrues notamment dans le domaine de la vitesse variable. Néanmoins des problèmes apparaissent tant au niveau de l’onduleur que de la machine lorsqu’on désire augmenter la puissance transmise. Les interrupteurs doivent en effet alors commuter des tensions et des courants d’amplitude plus élevée (coût unitaire plus élevé pour les modules et pollution électromagnétique accrue). Par ailleurs, à courant donné, l’augmentation de la puissance mène à des contraintes en tension pour les isolants. Ce dernier effet de contrainte (accélération du vieillissement des diélectriques) est d’autant plus accentué lorsque la machine est alimentée « classiquement » par un onduleur de tension fonctionnant en Modulation de Largeur d’Impulsions. Une piste classique pour la résolution de ces problèmes est celle, toute électronique, des convertisseurs multi-niveaux. Un fractionnement de la puissance par augmentation du nombre de phases de la machine est une solution alternative et/ou complémentaire. A puissance et courant donnés les contraintes en tension diminuent. La multiplication du nombre de phases permet l’utilisation de modules d’électronique de puissance identiques de moindre coût unitaire (élément favorable en terme de coût de maintenance). De plus, ce type de structure polyphasée permet d’augmenter la tolérance aux pannes du convertisseur électromécanique. En fait, il s’agit de répartir les contraintes entre le convertisseur électromécanique et le convertisseur statique. De même, dans le cas des machines basses tensions (automobile par exemple), la présence de courants d’intensité très élevée nécessite en général une mise en parallèle de nombreux interrupteurs qu’il peut être judicieux (pour des raisons de surdimensionnement notamment) de répartir entre plus de 3 phases. Là encore, les machines polyphasées constituent une alternative économique d’autant qu’elles permettent de réduire les pulsations de couple et donc le bruit d’origine électromagnétique. La problématique de recherche est l’étude et le développement d’ensembles complets comprenant le convertisseur statique, le convertisseur électromécanique polyphasé ainsi que la commande. En effet, l’adéquation entre la machine et le convertisseur est encore plus nécessaire que dans le cas d’une machine triphasée, la commande du convertisseur ne pouvant raisonnablement compenser certains défauts constructifs de la machine. Ainsi, un onduleur de tension qui alimente une machine polyphasée dont le bobinage est optimisé pour obtenir une force magnétomotrice sinusoidale va induire des courants parasites de forte amplitude dans la machine. Il est ainsi nécessaire de reprendre la conception du bobinage pour « désensibiliser » la machine. L’adéquation du convertisseur électromécanique au convertisseur statique est recherchée d’une part en agissant sur les paramètres constructifs de la machine polyphasée afin de l’adapter le plus possible au convertisseur dont le caractère discret impose des contraintes à la machine. D’autre part, on agit également sur les degrés de liberté offerts par la commande du convertisseur statique (choix des vecteurs tension activés) afin d’exploiter au mieux la machine polyphasée (réduction des courants parasites, marche dégradée…). C’est donc une approche SYSTEME qui allie simultanément la conception de machine à celle de la commande de convertisseur d’électronique de puissance.

Avion et électricité, de l'électrotechnique haute performance

Cet ouvrage répond à la nécessité d’intégrer à la formation de l’électricien, outre la matière, notamment la mécanique et la thermique. La première partie rappelle les notions de mécanique, de thermique et d’électromagnétisme indispensables pour aborder les applications du génie électrique. La seconde partie propose trente exercices, avec corrigés détaillés liés à des applications très diverses du génie électrique. Éléments de mécanique du solide. Phénomènes thermiques. Présentation de l’électromagnétisme. Électrostatique. Magnétostatique. Notions et outils pour l’étude des phénomènes magnétiques. États quasistationnaires. Matériaux magnétiques. Propagation d’ondes dans les lignes. Exercices de mécanique corrigés. Exercices de thermique corrigés. Exercices d’électromagnétisme corrigés.

Ce chapitre est consacré à la modélisation et la commande de machines électriques comportant au moins deux courants statoriques indépendants. La machine triphasée couplée en étoile sans neutre sorti ou en triangle en constitue la plus élémentaire. Plus précisément, l’objectif de ce chapitre est de mettre en évidence les spécificités qu’induit un nombre de courants indépendants supérieur à deux par rapport à la machine triphasée classique.

This chapter discusses the modeling and control of voltage source inverters associated with multiphase loads of various topologies. Such inverters have mostly been developed for the supply of multiphase electrical machines, but we will focus on the inverters and will not discuss these machines in the current chapter. We will however note that present-day development of these machines is closely linked to the development of the voltage source inverters that supply them. As the number of phases is increased beyond three, specific problems are encountered in electrical drives where inverter/machine/control coupling becomes more complex. This coupling explains the specific interest in three-phase systems, particularly in terms of spatial and temporal interactions between harmonics. Although such multiphase systems have been developed since the 1960s in niche applications (high power applications requiring a high tolerance to power outages) using thyristor current source inverters, the advent of high speed computational aids such as DSPs and, more recently, powerful FPGA networks has led to a rapid expansion in the use of voltage source inverters since the turn of the century. As the number of phases and legs is increased, additional degrees of freedom become available in terms of both design and control. Although a unified consideration of the constraints on the machine and the inverter is necessary for the design of high performance systems, it is first important to understand the detailed operation of each component part. This chapter is dedicated to the type of static converter consisting of a two level n-leg voltage source inverter. We will discuss in detail the modeling and control of these inverters, attempting to avoid where possible discussing the characteristics of the multiphase loads themselves. We will begin by discussing vector modeling of an n-leg inverter without taking into account the constraints imposed by the load (modification of the number of degrees of freedom). We will demonstrate vector modeling using the specific case of modeling two-level voltage source inverters with two and three legs. This approach enables us to generalize various known results, obtained using a space vector approach, to multiphase systems. In the context of this vector model we will discuss the principle of controlling mean values using Pulse Width Modulation. The second part of the chapter focuses on studying the influence of connection topology between the load and the inverter. We will discuss various types of multiphase loads and examine their influence on the capabilities of the inverter in terms of control. The justification of a vector approach relies on the fact that it not only benefits from the generality offered by matrix-based approaches but also lends itself to visual representations such as the complex phasor approach developed for three-phase systems. Visual representations, widely used in electrical engineering since their introduction by Fresnel, make it possible to rapidly handle various problems such as the choice of modulation strategy, inverter saturation, harmonic injection, etc.

Ce chapitre est consacré à la modélisation et la commande d’onduleurs de tension associés à des charges polyphasées de topologies différentes. Ces onduleurs se développent principalement dans le cadre de l’alimentation de machines électriques polyphasées dont l’étude sort du cadre de ce chapitre. On notera néanmoins que le développement actuel de ces machines est étroitement lié à celui des onduleurs de tension qui les alimentent. L’augmentation du nombre de phases au-delà de trois pose des problèmes spécifiques d’entrainements électriques dans la mesure où les couplages onduleur/machine/commande deviennent plus complexes. Elles mettent en évidence la particularité des systèmes triphasés notamment en termes d’interactions entre harmoniques qu’ils soient spatiaux ou temporels. Bien que ces systèmes polyphasés se développent depuis les années 1960 dans des secteurs de niches (forte puissance nécessitant une tolérance aux pannes élevée) avec des commutateurs de courant à thyristors, l’avènement de moyens de calculs rapides de type DSP et plus récemment de puissants réseaux FPGA a permis à partir des années 2000 un fort développement de l’usage d’onduleurs de tension. L’augmentation du nombre de phases et de bras apporte des degrés de libertés tant au niveau de la conception que de la commande. Même si la prise en compte conjointe des contraintes existantes sur la machine et l’onduleur est un enjeu à la réalisation de systèmes performants, il est nécessaire dans une première étape de présenter les spécificités de chaque partie. Ce chapitre est consacré au convertisseur statique qu’est l’onduleur de tension n-bras deux niveaux. On s’attachera à présenter les spécificités en termes de modélisation et de commande de ces onduleurs en essayant de s’affranchir le plus possible des caractéristiques des charges polyphasées. Dans un premier temps la modélisation vectorielle d’un onduleur à n-bras est présentée sans tenir compte des contraintes imposées par la charge (modification du nombre de degrés de liberté). On aborde la modélisation vectorielle par l’exemple (modélisation d’onduleurs de tension à deux niveaux possédant deux et trois bras), approche permettant de généraliser aux systèmes polyphasés des résultats connus obtenus par l’approche des vecteurs d’espace. Dans le cadre de cette modélisation vectorielle, le principe de la commande aux valeurs moyennes par Modulation de la Largeur des Impulsions est explicité. La deuxième partie du chapitre est consacrée à l’étude de l’influence de la topologie des connexions entre la charge et l’onduleur. On détaille différents types de charges polyphasées et on examine leur influence sur les potentialités de l’onduleur en termes de commande. La justification de l’approche vectorielle tient dans le fait qu’elle bénéficie d’une part de la généralité procurée par les approches matricielles mais qu’elle permet également d’autre part des représentations visuelles du type de celles des phaseurs complexes développées pour les systèmes triphasés. La représentation visuelle, très développée en électrotechnique depuis Fresnel, permet rapidement de juger de différents problèmes comme le choix de la stratégie de modulation, la saturation de l’onduleur, l’injection d’harmoniques, etc…

Chapitre 4, « Propriétés vectorielles des systèmes électriques triphasés », traité "Modélisation des machines électriques", aux éditions Hermes, 2004, pp. 181-246.

La démarche générale du mémoire consiste à utiliser des outils mathématiques permettant d’élaborer un formalisme vectoriel applicable aux systèmes électriques au sens large. Ce formalisme bénéficie à la fois des propriétés graphiques et géométriques de la théorie des vecteurs d’espace qu’il généralise et de la puissance du calcul matriciel. Aussi, est-il tout particulièrement adapté à l’étude des systèmes polyphasés. Tout d’abord, on caractérise les modulateurs d’énergie indépendamment de leurs charges. Pour cela des espaces vectoriels leur sont associés ainsi que des familles de vecteurs qui les caractérisent. Il est possible alors de définir quel type de charge le modulateur est capable de contrôler. Les degrés de liberté de la commande trouvent également une formulation mathématique. Les exemples traités sont les onduleurs de tension monophasé et triphasé deux niveaux. L’approche conduit, dans le cas d’une commande aux valeurs moyennes, à un calcul original des durées de conduction des interrupteurs en utilisant la notion de barycentre. Les algorithmes obtenus, généralisables aux onduleurs à n bras, comportent un nombre réduit d’opérations logiques et arithmétiques. Le formalisme est ensuite appliqué à la machine asynchrone triphasée avec q barres au rotor ; ceci nous permet d’expliciter la notion de rotor diphasé équivalent. La machine asynchrone pentaphasée est également modélisée et l’approche développée met en évidence les conditions que doit remplir l’onduleur à 5 bras pour l’alimenter correctement. Dans la dernière partie, un onduleur de courant à Modulation de Largeur d’Impulsions est étudié à l’aide du formalisme. Les non-linéarités de la commande sont prises en compte vectoriellement, notamment, de façon originale, celle concernant la durée minimale de conduction des interrupteurs. On décrit enfin l’implantation matérielle de cette commande sur microcontrôleur 16 bits et présente les résultats expérimentaux dans le cas d’une charge constituée d’une machine asynchrone triphasée en parallèle avec des condensateurs.