Fiche individuelle

This article presents a bridge between topology optimization (TO) and additive manufacturing. On the one hand, it presents an algorithm that considers the design variables as binary and then solves the problem by binary linear programming to optimize a ferromagnetic core. On the other hand, a 3-D printing process is developed to manufacture the shapes obtained by TO. Finally, these magnetic parts are characterized through electrical measurements.

The performance and energy efficiency of electro-mechanical converters are strongly bound to the properties of their magnetic cores. The latter are mostly made from stacked laminations of soft magnetic materials, such as Fe3%Si, which limits the core geometry design. However, when complex geometries are required, usually forging processes may be employed but with very low silicon steels (<0.5%) to be able to forge the steel. In that case, the low silicon content yields to higher electrical conductivity and then to higher eddy current loss. In this work, an additive manufacturing technique allowing to build complex geometries is studied with Fe3%Si magnetic materials. The fabrication process allows to obtain green parts which are then densified through debinding and sintering steps. The magnetic characterization is performed on toroidal cores and allows to observe a high level of magnetic induction and relative permeability. Finally, the impact of the printing strategy on the magnetic performances is investigated.

Nowadays, additive manufacturing of metallic materials is most often carried out using expensive and complex tools that leave the user with limited control and no possibility of modification. In order to make the printing of metal parts more accessible to small structures but also better suited for academic research, the use of a mixture of thermoplastic polymer and metal powder is a good solution as many granular feedstocks already exist for Metal Injection Molding applications. To perform the shaping process, the Fused Granular Fabrication 3D printing technology is set up by diverting the use of a feedstock in the form of pellets that are directly inserted into the print head. This solution, which is less costly, is implemented here by modifying a mid-range printer, the Tool Changer from E3D, and by making the hardware and software adaptations to mount a compact granulates extruder on it, which is also available on the market. The polymer portion present in the green part can then be removed in order to perform the heat treatments that will densify the powder by sintering and give a fully metallic dense object.

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.

D. Fu, J. Gong, Y. Xu, F. Gillon and N. Bracikowski, "Coupled Circuit and Magnetic Model for a Transverse Flux Permanent Magnet Linear Motor," in IEEE Access, vol. 8, pp. 159274-159283, 2020, doi: 10.1109/ACCESS.2020.3020258. Abstract: In this paper, a strong coupling between magnetic and electric phenomena is provided allowing to have an accurate and high-speed coupled model. A coupled circuit and magnetic model for an E-core transverse flux permanent magnet linear motor (TFPMLM) is proposed, which has an advantage linked to reducing time computing more than ten times when compared to 3-D finite-element model (FEM). Firstly, a multi-plane flexible-mesh nonlinear equivalent magnetic network (EMN) model is proposed to improve the computation efficiency as well as the high precision of the magnetic model. And a new method to define the converged iterative process is presented to further decrease the computing time. Secondly, the magnetic circuit and electric circuit are normalized into a solution matrix by introducing controlled sources and discretization methods which forms the coupled model. Then, the magnetic flux in the magnetic circuits and the current in the electric circuits are obtained simultaneously for each time step. The characteristics such as the air-gap flux density distribution, output thrust force waveforms and the phase currents are analyzed by the proposed coupled model. The modeling approach is approved by comparison with the 3-D FEM model. Finally, the proposed model is validated through the experimental setup with the machine prototype. keywords: {couplings;finite element analysis;iterative methods;linear motors;magnetic circuits;magnetic flux;permanent magnet motors;iterative process;computation efficiency;EMN model;TFPMLM;coupling;flexible-mesh nonlinear equivalent magnetic network model;3-D finite-element model;E-core transverse flux permanent magnet linear motor;high-speed coupled model;electric phenomena;magnetic phenomena;coupled circuit;electric circuit;magnetic circuit;Integrated circuit modeling;Magnetic circuits;Magnetic flux;Atmospheric modeling;Computational modeling;Permanent magnet motors;Solid modeling;Coupled model;electric circuit;equivalent magnetic network (EMN);linear motor;transverse flux}, URL: https://ieeexplore-ieee-org.ressources-electroniques.univ-lille.fr/stamp/stamp.jsp?tp=&arnumber=9180311&isnumber=8948470

The electromagnetic noise generated by the Maxwell radial pressure is a well-known consequence. In this paper, we present an analytical tool that allows air gap spatio-temporal pressures to be obtained from the radial flux density created by surface permanent magnet synchronous machines with concentrated winding (SPMSM). This tool based on winding function, a global air-gap permeance analytical model and total magnetomotive force product, determines the analytical air-gap spatio temporal and spectral radial pressure. We will see step-by-step their impacts in generating noise process. Also two predictive methods will be presented to determine the origin of the lows radial pressure orders noise sources. The interest lies in keeping results very quickly and appropriate in order to identify the low order electromagnetic noise origin. Then through an inverse approach using an iterative loop a new winding function is proposed in order to minimize radial force low order previously identified and chosen.

Transient simulations of models are required for the study of several phenomena and calculation of some physical quantities. For instance, in the case of a switched reluctance machine (SRM), conducting transient simulations allows the calculation of electromagnetic torque ripple. This can be very time consuming, especially when using an iterative optimization algorithm to smooth the developed electromagnetic torque. In this paper, Output Space Mapping Proportional (OSMP) and Manifold Mapping (MM) are presented as a solution to accomplish a fast determination of the optimal control parameters of a SRM in order to improve its performance. A description of the considered optimization …problem is also provided, along with a detailed presentation of the coarse and fine models used. Finally, optimization results are presented, analyzed and validated using finite element-based model as well as measurements on the SRM prototype.

novel transverse-flux permanent magnet linear motor (TFPMLM) named as double-sided double-excited one is proposed in this paper. Firstly, the operational principle and structural advantages of the TFPMLM are presented. Then, the 3-D magnetic circuit structure of the TFPMLM is simplified equivalently into a 2D one in order that Schwarz-Christoffel (SC) mapping method can be adopted to analyze the motor's magnetic field and characteristics. Then, the air-gap flux density distribution, back voltage and force waveforms when at no-load and at load are calculated by SC mapping method and 3-D FEM respectively for a prototype linear motor, The results from the two methods coincide much better with each other. At last, influences of magnet shape on cogging force are studied by SC method.

This paper presents performance improvements of a double excitation synchronous motor by using a reluctance network (RN). The distinguishing feature of the double excitation principle is to use permanent magnets with high energy, while air-gap flux is flexibly controlled by field windings. Therefore, the first contribution of this paper focuses on maximizing air-gap flux range control. Second, an approach for torque ripple reduction is proposed by directly modifying air-gap flux according to the instantaneous torque profile. The achieved resultant torque stays almost constant for a case study. The validity of the RN method is examined by comparisons with 3-D finite element and experimental results for several machines.

Abstract— This paper presents an analysis of low the space order of the air-gap radial Maxwell pressures in Surface Permanent Magnet Synchronous Machines (SPMSM) with fractional slot concentrated windings. The air-gap Maxwell pressures result from the multiplication of the flux density harmonics due to magnetomotive forces and permeance linked to the magnet, the armature, and the stator slots and their interactions. One low space order is selected and different approaches are compared to determine the origin of this pressure. First, an analytical prediction tool ACHFO (Analytical Calculation of Harmonic Force Orders) is issues to calculate the space and time orders of these magnetic pressure harmonics while identifying their origin in terms of interactions between magnet, armature and teeth effects. Additionally, the analytical prediction of ACHFO is compared with the flux density convolution and finite element approaches. The main advantage of our tool is the speed of computation. Finally, an experimental Operational Deflection Shape measurement (ODS) is performed to show the deflection shape of the low space order selected. Keywords— air-gap radial Maxwell pressures; lowest space order; analytical tool; convolution analysis; operational deflection shape.

– The purpose of this paper is to compare two design optimization architectures for the optimal design of a complex device that integrates simultaneously the sizing of system components and the control strategy for increasing the energetic performances. The considered benchmark is a battery electric passenger car. Design/methodology/approach – The optimal design of an electric vehicle powertrain is addressed within this paper, with regards to performances and range. The objectives and constraints require simulating several vehicle operating points, each of them has one degree of freedom for the electric machine control. This control is usually determined separately for each point with a sampling or an optimization loop resulting in an architecture called bi-level. In some conditions, the control variables can be transferred to the design optimization loop by suppressing the inner loop to get a mono-level formulation. The paper describes in which conditions this transformation can be done and compares the results for both architectures. Findings – Results show a calculation time divided by more than 30 for the mono-level architecture compared to the natural bi-level on the study case. Even with the same models and optimization algorithms, the structure of the problem should be studied to improve the results, especially if computational cost is high. Originality/value – The compared architectures bring new guidelines in the field optimal design for electric powertrains. The way to formulate a design optimization with some inner degrees of freedom can have a significant impact on computing time and on the problem understanding.

Purpose – Discrete highly constrained optimization of induction machine taking into consideration two objective functions: efficiency and total costs of production. The paper aims to discuss these issues. Design/methodology/approach – Interactive and semi-interactive interval-based optimization methods were used. Two concepts of multi-objective discrete optimization were proposed. Findings – Proposed methodology and algorithms allow decision maker (DM) participate in the process of optimal design and therefore decrease the total time of optimization process. The search procedure is straightforward and it does not require special skills of DM. Presented methods were successfully versified for the problem of optimal design with discrete variables. Research limitations/implications – Three interval algorithms suitable for inverse problems are researched and verified. It generally can be used for multi-objective problems. The dominance principles for interval boxes are showed in the paper. Proposed algorithms are based on the idea of hybridization of exact and evolutionary methods. Practical implications – Proposed approaches were successfully implemented within computer-aided application which is used by manufacturer of high power induction machine. Originality/value – The concept of pareto-domination using the interval boxes can be treated as original. The paper researched several elimination rules and discusses the difference between different approaches.

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

Purpose – The purpose of this paper is to develop an optimal approach for optimizing the dynamic behavior of incremental linear actuators. Design/methodology/approach – First, a parameterized design model is built. Second, a dynamic model is implemented. This model takes into account the thrust force computed from a finite element model. Finally, the multiobjective optimization approach is applied to the dynamic model to optimize control as well as design parameters. Findings – The Pareto front resulting from the optimization approach (or the parallel optimization approach,) is better than the Pareto, which is obtained from the only application of MultiObjective Genetic Algorithm (MOGA) method (or parallel MOGA with the same number of optimization approach objective function evaluations). The only use of MOGA can reach the region near an optimal Pareto front, but it consumes more computing time than the multiobjective optimization approach. At each flowchart stage, parallelization leads to a significant reduction of computing time which is halved when using two-core machine. Originality/value – In order to solve the multiobjective problem, a hybrid algorithm based on MOGA is developed

Purpose – The purpose of this paper is to present an application of a multidisciplinary multi-level design optimization methodology for the optimal design of a complex device from the field of electrical engineering throughout discipline-based decomposition. The considered benchmark is a single-phase low voltage safety isolation transformer. Design/methodology/approach – The multidisciplinary optimization of a safety isolation transformer is addressed within this paper. The bi-level collaborative optimization (CO) strategy is employed to coordinate the optimization of the different disciplinary analytical models of the transformer (no-load and full-load electromagnetic models and thermal model). The results represent the joint decision of the three distinct disciplinary optimizers involved in the design process, under the coordination of the CO’s master optimizer. In order to validate the proposed approach, the results are compared to those obtained using a classical single-level optimization method – sequential quadratic programming – carried out using a multidisciplinary feasible formulation for handling the evaluation of the coupling model of the transformer. Findings – Results show a good convergence of the CO process with the analytical modeling of the transformer, with a reduced number of coordination iterations. However, a relatively important number of disciplinary models evaluations were required by the local optimizers. Originality/value – The CO multi-level methodology represents a new approach in the field of electrical engineering. The advantage of this approach consists in that it integrates decisions from different teams of specialists within the optimal design process of complex systems and all exchanges are managed within a unique coordination process.

Multi-objective optimization with 3D finite element model is a complex and time consuming process. Output space-mapping techniques allow having an affordable computation cost with a minimum number of computationally expensive FEM evaluations. In this paper, a three-level adapted output space-mapping technique is proposed to assist two-objective optimization problems. Three models having different granularity and describing the same device are used jointly in the optimization process. The results for the safety isolating transformer show that the proposed algorithm allows saving a substantial amount of computation time compared to the classical two-level output space-mapping technique.

Optimal design with finite element model is often expensive in terms of computation time. The output space mapping technique allows benefiting both the rapidity of the analytical model and the accuracy of the finite element model. In this paper, a three-level output space-mapping technique is proposed to reduce the computation time. Three models having a different granularity and describing the same device are used jointly within the optimization process. Proposed strategy is applied for solving the optimal design problems of two electromagnetic devices. Results show that three-level output space mapping strategy allows saving a substantial computation time compared to the classical two-level output space-mapping.

The optimal design of electromagnetic devices needs to address two particular aspects: 1) the use of accurate tools and 2) the limited time budget affected to this task. In order to respond to these issues, two low evaluation budget multiobjective optimization techniques — efficient global optimization (EGO) and output space mapping (OSM) — are investigated in this paper with regard to a biobjective optimization benchmark. The device to be optimally sized is a low-voltage safety isolating transformer, represented through two levels of modeling: 1) coarse (analytical model) and 2) fine (numerical 3-D FEM). The biobjective character of the problem is accounted for by OSM through an epsilon-constraint technique. A transformation technique is set up with EGO by considering the constraints as an additional objective function in order to handle the constraints of the initial optimization problem. The biobjective comparison of the two techniques on the transformer benchmark is discussed.

The optimization of electromagnetic devices by direct use of finite element models is computationally expensive. This paper presents two effective surrogate-assisted optimization algorithms: Output Space Mapping and Efficient Global Optimization which are employed with regard to a minimum number of finite element model evaluations. A parallel between both algorithms is made through a single phase safety isolating transformer optimization problem using 3D finite element models.

Conceiving electromagnetic devices using finite element modeling tools is a complex task and also time-costly. The Efficient Global Optimization method, based on the progressive construction of surrogate models is studied. The method uses Kriging models and allows for multi-objective optimization. An original infill criterion, combining the surrogate models and an estimate of their error is proposed. Moreover, two techniques for the calculi distribution, adapted to the algorithm, are tested on an 8-core machine. An advantage of the method consists in its capability of providing sufficiently accurate models for each objective and constraint function around the obtained Pareto front. The superconducting magnetic energy storage (SMES) device of the TEAM problem 22 is used as benchmark.

In this paper, traction system design in carried out with a multilevel optimization technique called Target Cascading. This methodology is based on a hierarchical breaking down and allows solving a problem with multiple parallel optimizations. The large-scale system design problem is usually decomposed into several linked optimization subproblems according to project organization structure. Target Cascading gives a new approach to formulate and to solve the complex system design optimization problem in the electrical field. The problem formulation is more suitable to this kind of problem than conventional methods because it is closer to a work organisation of design engineers.

The optimal design method is applied to a complex system design. It replaces trial-and-error process, often performed by engineers, while ensuring the system optimality. A surrogate model is used in order to accelerate the optimization process when the simulation time is high. A hybrid optimization algorithm is proposed allowing a compromise between global and local search. The optimization of tram traction system is presented as an application of this method.

In this paper, target cascading methodology is presented and adapted to improve its convergence in the case of the optimisation design of an electric system. With target cascading, the overall system problem is decomposed into sub-problems, which are solved separately and coordinated via conjoint targets. The methodology allows solving complex problem with strong interactions.

The optimal design method is applied to a complex system design. It replaces trial-and-error process, which is often performed by engineers, while ensuring the system optimality. The surrogate model is used in order to accelerate the optimization process when the simulation time is high. A hybrid optimization algorithm is proposed allowing a compromise between global and local search. The optimization of tramway traction system is presented as an application of this method.

In railway electrical traction system, the Pulse Width Modulation (PWM) technique is used for both rectifier and inverter. PWM generates voltage and current harmonic in DC link. A Damping Circuit is introduced in order to reduce the harmonic currents, which cause the over sizing design and the reduction in lifetime of the capacitor. The optimization technique is applied to obtain the optimal value of damping circuit in terms of capacitor lifetime, weight and price of damping circuit components.

In traction application, the electric motor design methodology is not trivial. This paper presents various design approaches using rated point or load cycle. Design optimizations of surface-mounted permanent magnet traction motor are carried out using these approaches. Therefore, a comparative study is done through optimal motors obtained from optimization techniques. This paper shows advantages and drawbacks of each approach in traction motor design.

The concept of multidisciplinary optimization is applied to design an electric motor. It combines finite elements and analytical models to form together a multidisciplinary model. The models represent different machine phenomena as electromagnetic, thermal but also vibro-acoustic. These models are linked through a constrained optimization process, the whole forming an optimal design tool

This paper presents a new methodology to design a traction electric motor. The methodology is based on an electric vehicle design model that uses energetic exchange. Each component is described by a response surface. For the drive motor, the surface provides instantaneously the consumption and gives the possibility to optimize its efficiency in the most utilized operating zones. The gain can rise until to 14%.

L’article présente une démarche de conception qui aboutie à la réalisation d’un moteur synchrone et à son intégration dans une pompe étanche pour fluides corrosifs. La machine synchrone à flux axial est proposée et sa construction dans le cadre de petites et moyennes séries est simplifiée. Pour cela, une structure à bobinages concentrés et à encoches droites est retenue. Les différentes configurations entre le nombre de pôles et de dents sont présentées. L’étape de dimensionnement analytique est détaillée et permet de sélectionner la configuration la mieux adaptée à l’application. Une dernière étape de modélisation éléments finis permet de valider les hypothèses faites lors du dimensionnement analytique et aide également au choix de la configuration la plus appropriée. Il apparaît clairement que l’utilisation des bobinages concentrés dans les structures à flux axial conjugue compacité et facilité de fabrication.

The paper highlights the process of electric vehicles optimal design as an inverse problem formulated as a global constrained optimization problem. A specific design model is built highlighting a non-linearity problem due to the sense used to elaborate the model. Each electric vehicle component is an energy-based model using the response surface methodology. In order to evaluate the model sensitivity the experimental design method is applied. Work is orientated to a global optimal design with a specific interest for the electric motor. The paper ends with an application in order to show the interest of treating the global problem simultaneously thanks to the constrained optimization technique.

In this paper, several ways to reduce the manufacturing cost of permanent magnet brushless direct current motors are explored. Actually, the most promising way seems to be a modular structure with axial flux, rolled metal sheet, straight slots and concentrated windings. Rules for optimality are presented and applied to transform a distributed winding into a concentrated one. All combinations of the number of poles with the number of teeth are explored and the five most interesting configurations are detailed. A calculation sheet is derived from the specifications, and gives the performances, the temperatures, the price and the bulk of the motor. It is validated using finite element analysis at no-load, locked rotor, and full-load. An optimization process is used to minimize the cost with respect to technical constraints. A prototype is built and shows good agreement between measurements and specifications. Moreover, the photos of axial flux motors with concentrated and distributed windings, side by side, emphasize the possible reduction in the manufacturing cost of the stator.

The concept of robust optimization of electromagnetic devices using finite element models is presented. An original ‘trellis’ experimental design is used to achieve the optimization process and a robustness analysis is done using the signal-to-noise ratio. The robustness study deals with modeling and building noises and is applied to the optimal design of a linear tubular actuator.

An efficient optimal design methodology developed for electromagnetical features of switched reluctance linear tubular actuators is reported. Its different steps are presented and applied. Its implementation delivers as final output optimized and robust geometries of linear actuators with respect to imposed need analysis. The efficiency of this methodology is proved using a virtual prototype of the studied actuator and validated by practical tests. The computing tools and techniques developed in this paper are general and completely parameterized so that they can be applied to the optimal design of any device of the same type.

This paper aims at displaying several modelling procedures of a same apparatus, thus bringing to the fore the contribution of each of them, then making a comparison with the experimental results obtained from the prototype. It can also be noticed that each model, depending upon its complexity level, can be helpful for a better understanding into the working process of this machine, taking into account phenomena so far neglected within a low-key modelling procedure. At the end, the beneficial effects of the teeth inserted between the main ones holding the stator winding of this machine is demonstrated.

In this paper, an optimization method, based on fractional experimental design, is proposed and applied to the design of a brushless DC motor. Taguchi’s methodology and a limited number of finite element simulations are used to build an approximation of the cost function of an optimization problem. This approximation allows to quickly locate the global optimum.

Efficient methods to optimize electrical machines are derived from the Design of Experiments Method (DOE) and applied to the shape optimization of a permanent magnet motor. Different experimental designs are used to build a simple model and to find the optimal response. A fully user-controlled approach and iterative algorithms are compared

The solution of a design problem of an electrical motor shows how the experimental design method can be combined with the numerical simulation and how this approach is well adapted to the optimization process. Firstly, the screening of significant geometric parameters is presented. Then the Response Surface Methodology is used to build an analytical model that is finally employed as a constraint in an obvious optimization process. As a result, the performance of the motor is increased

A practical methodology to optimize electrical devices, based on a combination of numerical simulation and the experimental design method, is illustrated on the shape optimization of a permanent magnet motor. Firstly, significant parameters are identified. Secondly, these parameters are used to improve the performance of the machine

A finite element model, taking into account 3D effects, is presented and used to optimise the performance of a permanent magnet motor. An optimisation of magnetisation field direction inside the magnets is realised using the experimental design method applied to numerical simulation. The advantages of this method are discussed in comparison with direct methods

HLP Planar inductors made of combined low permeability (LP) and high permeability (HP) planar cores allow to achieve better performance compared to traditional planar inductors with air gap. In this paper, an optimization methodology is proposed to design high performance HLP planar inductors. Based on magnetic, loss and thermal models, an optimal design process is developed and applied to the case of a planar inductor operated in a 20-kW SiC-based buck converter.

The leakage inductance of high-frequency (HF) transformer is a key parameter to help improve the power density of isolated DC/DC converters. Minimized, it can reduce the losses, but maximized or precisely tuned, the leakage inductance can intervene in the converter operation, avoiding supplementary HF inductor. This is the case for soft-switching converters or specific topologies like dual active bridge for example. The present work aims to adjust the value of a planar transformer (PT) leakage inductance, acting on the positioning of the conductors within the PT winding window. The methodology developed here is based on finite element analysis (FEA) simulation as well as single and multi-objective optimizations to adjust the value of the leakage inductance while minimizing the AC resistance. The optimization is carried out for different interleavings, questioning the usual choices of interleavings known to minimize or maximize the leakage inductance.

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.

High-Frequency (HF) transformer is a central part of isolated HF power converters. Its parameters, in particular leakage inductance and losses, have a significant impact on the overall converter performances. With the increase of switching frequencies linked to the use of SiC and GaN based active devices, the control of the HF transformer parameters becomes essential. A HF transformer is usually designed without considering its surrounding. However, the latter can have a significant impact on the transformer's performance. In this paper, the effect of an aluminum casing surrounding the transformer is studied and quantified for two parameters: The transformer leakage inductance and the supplementary losses. The goal is to consider the casing effect in the early design stage of power converters.

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.

Fabrication of soft magnetic ceramic materials relies on time consuming conventional methods, such as molding and sintering, which restricts the possibilities of shapes the components can be given. Additive manufacturing of such materials can help reduce production lead time and unlock topological design limitations. In this work, the implementation of an indirect additive manufacturing methods for soft magnetic Mn-Zn ferrite, intended for high frequency applications, is presented. A blend of light sensitive polymer binder and fine powder is used for the shaping stage using Digital Light Processing (DLP) followed by a heat treatment that allows to remove the polymer part and to obtain a final dense part. Simple shapes were produced in order to characterize their magnetic performances and to validate this method for further fabrication of more complex magnetic core.

The performance and energy efficiency of electro-mechanical converters are strongly bound to the properties of their magnetic cores. The latter are mostly made from stacked laminations of soft magnetic materials such as Fe3%Si which limits the core geometry design. However, when complex geometries are required, usually forging processes may be employed but with very low silicon steels (<0.5%) to be able to forge the steel. In that case, the low silicon content yields to higher electrical conductivity and then to higher eddy current losses. In this work, an additive manufacturing technique allowing to build complex geometries is studied with Fe3%Si magnetic materials. The fabrication process allows to obtain green parts which are then densified through a final sintering step. The electromagnetic characterization of samples is performed. Finally, the results and possible improvement will be discussed in comparison with conventional Fe3%Si electrical steels and a forged magnetic steel that is commonly found in electromechanical applications.

In this work, we propose an FDM additive manufacturing process that uses a feedstock in the form of small pellets composed of a similar mix of 316L Stainless Steel powder bound by a thermoplastic polymer. The printing stage is performed using an affordable Archimedes screw system that is mounted on a classical 3-axis cinematic frame. The feedstock, provided by PolyMIM, is diverted from its original use, which is Metal Injection Moulding (MIM), and is intended to be debinded and sintered. This allows to consider a wide range of materials already available. The impact of the deposition strategy on the tensile properties will be investigated in relation with the microstructure.

This paper presents a topology optimization process for tuning the leakage inductance of a High Frequency (HF) transformer. The 2D Magnetic Equivalent Circuit (MEC) is used to model the studied transformer. Then, through an optimization problem, primary winding positions ensuring maximal and minimal leakage inductances will be gotten.

To design and study an electrical machine, Finite Element Model (FEM) is nowadays the most accurate approach as it takes into account different phenomenon. However, it is also time-consuming which does not always make it suitable for an optimization process. Analytical model can then be used but it has to be as accurate as possible in order to obtain valid and relevant results. In case of squirrel cage induction machines, several analytical models have been proposed under different simplifying hypothesis [1]–[3] The well adapted one is the approach involving winding function to determine the armature Magneto Motive Forces (MMF) along with the air gap permeance. These two quantities can be expressed in a relatively accurate way [4]. The problem then remains in taking into account the rotor part in order to determine the currents which circulate in the bars of the squirrel cage. Indeed, in addition to the well estimate of the magnetic flux through the rotor surfaces, the determining of the elements of the equivalent electrical circuit which makes it possible to precisely calculate the currents of the bars in the most accurate way is required. In the present paper, an analytical model of the squirrel cage based on an equivalent electrical circuit along with the approach to accurately identify its parameters is proposed. This model that enables to determine the rotor bar currents can be generalized to any structure and thus be used either for design or optimization purposes. Results obtained in the case of an induction machine prototype are compared to the ones given by FEM.

Magneto Motive Force is an important quantity to analyze electrical machine performances. Indeed, the latter is directly linked to that of the air gap magnetic flux density and thus to the torque ripples, vibration and then noise. This paper proposes to reduce the MMF harmonic content by means of optimization process using mono-objective or multi-objective algorithms with discrete and continuous variables. For this aim, optimization algorithm is coupled with an analytical tool which enables calculating quickly the MMF harmonic content from winding parameters. A winding optimization of three different windings with the same number of pole pairs is proposed to show the suitability of this process.

Study of the impact of stator MMF from different winding distributions using FEM can be tedious when taking into account the stator slots as it introduces mesh constraint and reluctance variation of the air gap. To avoid this fact, a current sheet spread all around the inner stator surface is used. In the proposed approach, the MMF is modelled by the equivalent current sheet of the real stator MMF in the air gap. This current sheet is coupled with an analytical tool that allows obtaining the spatio-temporal stator MMF of any winding considered. Compared to an analytical model, the proposed approach enables taking into account the non linear behaviour of magnetic material in the yoke and thus testing different combinations of stator windings in more realistic conditions.

Permanent magnet brushed DC motors are used in several applications such as home automation or automotive industry. This is mainly due to their lightweight, low cost and compact structure. Thus, the importance to study the sources of noise and vibration in these motors, which is often complicated and can be attributed to many factors. In this paper, the cogging torque and electromagnetic forces are studied in the case of a small permanent magnet brushed DC motor with 2 poles and 3 slots. Addition of dummy slots on the rotor side is described with its effect on the evolution of both aspects. The aim of this study is to give the quantitative effect about torque ripple and radial forces for each harmonic in relation with these dummy slots.

Magneto motive force is a key quantity of the energy conversion in the electrical machines. Its harmonic content is important as it leads to the one of the magnetic flux density in the air gap. To analyze it, a first step consists to study the winding function. Many tools already exist to tackle this point but generally they use some methods like Star of slots or matrix representation and the harmonic content is obtained by a Fast Fourier Transform of the total winding function. In the present paper, we propose to build up the winding function using elementary patterns whose harmonic contents are used to reach the one of the whole function using a geometrical construction. This approach is quite fast and allows easy analyzing in order to reduce or cancel a magnetic harmonic.

The magneto motive force is an important physical quantity for electrical machines. Indeed its harmonic content leads to that of the air gap flux density. This paper presents an optimisation of the winding distribution for three phase fractional slot concentrated winding (FSCW) and distributed winding (DW) in order to reduce the magneto motive force harmonic content. This have an important effect on torque ripples, vibration and then noise. The optimization will be done on continue and discrete variables linked to the winding distribution.

The aim of this paper concerns the design with these targets for low power motors that offer a good compromise in terms of performance: speed, torque, current, and noise linked to the radial forces. Different low power machines and topologies are studied with the same constraints in term of volume for the same value of the torque. The study is carried out on a PMSM with surface permanent magnet ‘SPM’ and with insert permanent magnet ‘IPM’. In order to reduce the cost, a synchronous reluctance machine ‘SynRM’ is also designed and studied. 2D and 3D Finite Element modeling are used to compare the performance of the three different topologies. In addition, the best solutions are realized and tested.

This paper studies different low power machines and topologies with the same constraints in term of volume for the same value of the torque. The aim of this paper concerns the design with these targets for low power motors that offer a good compromise in terms of performance: speed, torque, current, and noise linked to the radial forces. The study is carried out on a PMSM with surface permanent magnet ‘SPM’ and with insert permanent magnet ‘IPM’. In order to reduce the cost, a synchronous reluctance machine ‘SynRM’ is also designed and studied. 2D and 3D Finite Element modeling are used to compare the performance of the three different topologies.

This paper presents a comparison between a Double Excitation Synchronous Machine (DESM) and a Permanent Magnet Synchronous Machine (PMSM). The comparison is based on optimal designs of both machine types aiming at minimizing material cost and losses according to different constant power speed ranges (CPSR). The result shows that DESM is more advantageous over the PMSM counterpart in loss saving at wide CPSR and DESM is capable of dealing with circumstances where very wide CPSRs are required.

Abstract—The presented paper proposes a topology optimisation methodology based on the density-based method SIMP, and applied to a numerical example to validate the former. The approach and methodology are detailed, and the results for a 3D basic electromagnetic example are presented. The non-linear B(H) curve is also taken into account. Index Terms—gradient-based algorithm, relaxation of variables, SIMP density method, weighted objective sum

This paper presents findings from an optimal design study on a switched reluctance machine operating in both motoring and generating modes as automotive integrated starter/alternator. The design optimization approach employs an analytical lumped-parameter modelling of the switched reluctance machine in motor and generator operations, which is refined by finite-element magnetic field analysis of the machine and then implemented in MATLAB/Simulink environment. The objective function of the design optimization problem is the maximization of the average electromagnetic torque of the machine for motor operating mode under constraints on rotor speed, energy efficiency and torque ripple. Steady-state and dynamic simulation results for the optimally-designed switched reluctance machine in motoring and generating modes, as part of automotive integrated starter/alternator operation cycle, are also provided.

This paper deals with a methodology developed for fast and accurate dynamic modeling of Hybrid Stepper motors. The proposed method is based on réluctance network magnetostatic modelling validated by finite element simulations

Abstract. This paper presents different approaches while using the SIMP density-based method for the Topology Optimisation (TO) of a 3D electromagnetic device. The methodology used for TO is also detailed in this paper. The initial model and the formulation of the problem are presented, and the results for two approaches are analysed. A Finite Element calculation code is coupled with a gradient-based algorithm to numerically execute the proposed methodology for TO. Keywords: 3D Finite Element Model, gradient-based fmincon SQP algorithm, SIMP density-based method, Topology Optimisation

An analysis of Hybrid Excitation Synchronous Generator (HESG) topologies for a direct drive wind turbine is investigated. Through an optimization process, the topologies of HESG are compared regarding the cost and the total losses. The optimizations are performed at the nominal on-load operating point of the generator. The trade-offs between each topology are analyzed according to a set of Pareto fronts. An instrumented prototype of 900kVA approves the design process. Finally, the best Pareto optimal solutions are compared during an experimental operating cycle of the direct drive wind turbine. The efficiency improvement emphasizes the interest of the design by optimization.

Transient simulations of models are required for the study of several phenomena and the calculation of some physical quantities. For instance, in the case of a switched reluctance (SR) machine, conducting transient simulations allows the calculation of torque ripple. This can be very time consuming especially when using an iterative optimization algorithm to smooth the developed torque. In this paper, Output Space Mapping Proportional (OSMP) and Manifold Mapping (MM) are presented as a solution to accomplish a fast determination of the optimal control parameters of a SRM in order to improve its performance. A description of the considered optimization problem is also provided, along with a detailed presentation of the coarse and fine models used. Finally, optimization results are presented, analyzed and validated using a FE model and measurements on the prototype.

This paper presents a methodology to optimise the topology of a 3D electromagnetic model to maximise Energy while constraining the Material Quantity. Variants of the material distribution method SIMP (Solid Isotropic Material with Penalisation) are discussed to enhance convergence of variables. The aim is to improve the results by analysing the behaviour of the design variables w.r.t the objectives. This allows correct parameter tweaking and finding the best variant for the SIMP Method respective to our methodology. This would help reduce the time consumed to find the best solution and therefore enhance the accuracy of the results.

This paper proposes an analysis of a classical salient pole synchronous generator assisted by permanent magnets. The improvements of inserting PM are investigated using semi-analytical models, finite element models, and also experiments on prototype of 900 kVA. The principle of assisted PM is clarified. Then a direct-quadrature reluctances model is developed to analyse the behaviour of the machine on an operating cycle. This machine is used in a direct drive wind turbine. By an optimization problem on the d-q equivalent model, the control strategy of the prototype is inferred from an experimental operating cycle.

The utilization of nodal based – generalized equivalent magnetic circuit method (EMCM) in the modeling of a double excitation synchronous machine (DESM) is presented in this paper. Nonlinear magnetization characteristic is taken into consideration. This method shows a distinguishing advantage over the finite element method (FEM) in term of computation time. The validity of the EMC results are examined by comparisons with 3D FEM.

This paper presents an analysis of the air gap radial Maxwell forces in some three-phase, inner rotor Concentrated Winding surface Permanent Magnet Synchronous Machine (CW-PMSM). Two modular winding machines and one asymmetric, winding machine are considered and simulated by a Finite Element method (FE). The air gap Maxwell pressure results from multiplication of the flux density harmonics due to magnetomotive forces and permeance linked to the magnet, to the armature, to the stator slots and their interactions. An analytical prediction tool, (Analytical Calculation of Harmonic Force Orders -ACHFO) calculates the space and time orders of theses magnetic force harmonics while identifying their origin in terms of, interactions between magnet, armature and teeth effects. Additionally, an experimental Operational Deflection Shape measurement (ODS) is realised, for one modular machine prototype, to validate the electromagnetic model results. Finally the analytical prediction of ACHFO is compared with another method to obtain the origin of low orders radial pressure based on radial flux density convolution combination approach.

For switched reluctance machines, a major problem is the torque ripple, which causes increased and undesirable acoustic noise and possible irregular speed. This paper aims at determining optimal turn-on and turn-off angles for torque ripple reduction of a three-phase 6/8 switched reluctance motor/generator. A commutation-angle optimization technique is therefore implemented for both motoring and generating operation modes over an extended speed range.

Vibration and acoustic noise can constitute a serious problem for Switched Reluctance Motors (SRMs). They are mainly caused by the deformation of the stator lamination stack due to its magnetic attraction to the rotor. This paper presents a 2D multi-physic methodology which permits to predict electromagnetic acoustic noise generated by SRMs, since the early design phase. In order to achieve the best compromise between accuracy and computational time, a hybrid methodology was adopted. It is based on a Finite Element (FE) magnetic model to take into account magnetic nonlinearities, especially for SRMs which are usually highly saturated. The vibration and acoustic models are based on analytic approaches and are integrated in an in-house tool we developed: GRIMM (Generic Ring Model for Magnetic Noise). This tool has been validated by a full FE approach for an 8/6 SRM at each step and good agreements are obtained. Its accuracy was improved by taking into account the stator teeth effect in terms of mass correction and by means of quasi-axisymmetry hypothesis.

This paper proposes a multi-structure model combining eight rotating machines. The interest of double excitation is considered through magneto-motive sources combinations. An 1MV prototype of Hybrid Synchronous machine with permanent magnets mounted on pole surfaces is presented and used to validate the studied model at no-load operating mode for two topologies. An optimization problem provides data for discussion on the industrial choices of the prototype structure.

This paper presents the reluctance network method used in modeling double excitation synchronous motor. The fringing effect and saturation are taken into account. This method shows its advantage in term of simulation time while maintaining a good accuracy; this fast model will accelerate the optimization process. The comparisons with 3D finite element method and experiment will be also investigated.

This paper presents an analysis of the radial Maxwell forces in the air gap of a concentrated winding for three-phase Permanent Magnet Synchronous Machine (PMSM). Many configurations are available with different windings or different topologies of stator-rotor. Radial forces versus time and spatial domains are the result of harmonics specific to the magnets, to the armature, to the teeth and their interactions too. A prediction tool (Analytical Calculation of Harmonic Force Orders - ACHFO) uses an analytical formulation; it gives the previous interactions, their own frequencies. Then a comparison will be made with finite element (FE) results.

The main advantages of the Switched Reluctance Motor (SRM) are its robust construction and its low cost which makes this technology an attractive solution for traction applications. However, one of its major drawbacks is the high mechanical vibrations and acoustic noise. These vibrations and acoustic noise are mainly caused by the deformation of the stator lamination stack due to its magnetic attraction to the rotor. The aim of this study is to build a complete coupled multi-physic tool allowing the prediction of electromagnetic acoustic noise in an 8/6 SRM. The goal of such a tool is to be integrated in an optimization process. This tool is based on 2D electromagnetic, vibration and acoustic models which are calculated through analytical approaches. The vibro-acoustic analytical results are compared to those of a FE approach and good agreements are obtained.

Vibration and acoustic noise can constitute a serious problem in electric machines. They are mainly caused by the deformation of the stator lamination stack due to its magnetic attraction to the rotor. This paper presents a 2D multi-physic tool which permits to predict electromagnetic acoustic noise generated by electric motors, since the early design phase. This tool is based on 2D magnetic, vibration and acoustic models and the final goal is to find the best compromise between accuracy and calculation time. The magnetic model is based on the Finite Element (FE) method in order to take into account nonlinearities, especially for SRMs which are usually highly saturated. The vibration and acoustic models are calculated through analytic approaches. The analytical results are then compared to those of a full FE approach for an 8/6 SRM and good agreements are obtained.

This paper aims to study the Hybrid Excitation Synchronous Machine (HESM) performances for railway traction. Owing to the extra degree of freedom provided by the DC field excitation coil, it is possible to improve the overall efficiency of operating cycle comparing to other structures. An optimization algorithm is implemented. It allows finding a compromise machine that minimizes the average cycle losses and the mass.

The multi-disciplinary optimization (MDO) of a safety isolation transformer is addressed here. The multi-level collaborative optimization (CO) method is employed to coordinate the optimization of the different disciplinary models of the transformer. Preliminary results show a good convergence of the CO process with an analytical model of the transformer, but with a non-neglecting number of disciplinary optimizations. To benefit from the accuracy provided by the 3D FE transformer disciplinary models within the CO process, with a reasonable computational cost, the use of the Output Space Mapping (OSM) technique is proposed for handling the disciplinary optimizations of the CO structure.

Generator reactive capability curve of a Hybrid Excitation Synchronous Machine (HESM) for high power applications has been studied in this paper. The machine consists on a salient pole synchronous generator with added permanent magnets pieces on poles surfaces. In order to have an accurate and reduced time computation performances prediction model of the HESM, analytical and equivalent circuit methods was used. The influence of the rate of hybridization on machine performances was investigated. The increase of the rate of hybridization leads to the generator reactive capability improvement. Also, it leads to the reduction of the mass of the machine active parts but at the expense of the increase of materials cost due to the excessive permanent magnets price

In this paper, we propose an application of interval analysis to the problems of optimal design of high power induction machines. The considered tool proved its usefulness as a decision-support system for design engineers. Interactive algorithm for bi-objective optimization is implemented. Gen- erally, it is suitable for any problems with discrete variables. Interval arithmetic is used for evaluating technical character- istics imposed by the customers in the form of requirements. In addition to that, total costs of machine evaluated by using interval methods. Proposed approach seems to be a powerful tool for aiding to make decisions during design procedures.

In the paper authors present interactive interval arithmetic-based approaches for resolving bi-objective optimization problems with discrete variables. These algorithms make part of the computer-aided design tool which is used by the engineers in large manufacturing company for finding the set of optimal configurations of induction machine. One case of its usage is illustrated and it is applied to the problem of optimal design of high-power induction machines.

In the article we show usage of different modications of branch and bound algorithm for the inverse problem of induction machine design. More specically, the task consisted in finding the domain of optimal congurations of induction machine taking into consideration technical specication. Two objective functions were chosen: efficiency of IM and its total costs of production. Considered problem had 20 constraints which must be satisfied for all optimal congurations. As a numerical model for calculating efficiency and all other parameters of IM we used conven- tional approach using equivalent circuit. For computing the total costs of production we employed the method of surrogate modelling using kriging approach. Optimization problem has 8 variables where all of them are geometrical parameters of IM. For each the feasible domain is finite, therefore gradient-free methods can only be applied for finding the set of global solutions. In the work, we used different branching strategies during the search procedure inside BB algorithm. Also we showed the application of interval version of BB algorithm for the same optimization problem. More formally, following approaches were tested for considered problem: depth-first search, A* search, hybridizing entropic branching, and interval branch-and-bound.

In the article two optimization methodologies based on interval branch-and-bound algorithm are presented. This technique let to decrease the total time of computation, even in spite of discrete nature of some of the design variables. Computational experiments performed on multivariable optimization problem reveal great accuracy and technical validity of developed approaches. As an example, the optimal design of the induction machine (IM) was treated, where the aim was to find the set of the most efficient and, at the same time, cheapest in the manufacturing configurations. In the study, numerical models had been used as confirmatory one.

Current economic situation force manufacturers to find the new ways of designing electrical machines. In order to succeed in competitive market, industry has to create new approaches of finding the solutions which will satisfy customer’s requirements. Task of determining this set of optimal configurations must be done in the least possible time frame. This problem is becoming more complex when the required electrical machine is not in the standard range of configurations and so the price of the solution cannot be determined with high precision. In this article we propose an example of industrial application which assists in defining the set of optimal configurations of induction machine where the criterions of optimality are the efficiency and total cost of manufacturing.

Optimal design of a double-sided linear induction motor using finite element models is complex and time consuming. Two strategies are tested to overcome these difficulties: firstly, the surrogate model-assisted optimization approach where computationally expensive functions are approximated by fast analytical models; secondly, the Efficient Global Optimization that is based on the progressive construction of a Kriging model used to drive the optimization problem. A multi-objective optimization is achieved with these both strategies applied on a finite element model. The resulting Pareto fronts are analyzed and compared in order to select the most appropriate method to take the good decision in afford time

The optimal design of electromagnetic devices needs to address two particular aspects: the use of accurate tools, and the limited time budget affected to this task. In order to respond to these issues, two low evaluation budget multi-objective optimization techniques - Efficient Global Optimization (EGO) and Output Space Mapping (OSM) - are investigated in this paper with regard to a bi-objective optimization benchmark. The device to be optimally sized is a low-voltage safety isolating transformer, represented through two levels of modeling: coarse (analytical model) and fine (numerical 3D FEM). The bi-objective character of the problem is accounted for by OSM through an epsilon-constraint technique. A transformation technique is set up with EGO, by considering the constraints as an additional objective function, in order to handle the constraints of the initial optimization problem. The bi-objective comparison of the two techniques on the transformer benchmark is discussed.

The end effects are the particular sensitive difficulty to model linear drives. Moreover an electrical machine model which only considers single physical aspect is not sufficiently accurate. In this paper, 3D magnetic and thermal models are achieved taking into account the end effects and the multi-physical aspects. For the first step, the linear motor is studied as a braking system with different displacement velocities. For the second step, the startup thrust force is studied with the coupling between the magnetic and thermal models. The both simulation results are compared to experimental results obtained by a test bench with the reduced scale

It is difficult to consider the end effects when modeling a linear induction motor. Based on Finite Element Method, this paper presents two models of a double-sided linear induction motor i.e. 2D finite element model and 3D finite element model. The traditional 2D model takes into account the longitudinal end effect but not the transverse edge effect. An improved 2D model considering the transverse edge effect and the winding overhang leakages is proposed and a 3D model which takes into account the both end effects is presented. A test bench is designed and presented in order to validate the models. The simulation results are compared to the measurements, which show that both the improved 2D model and 3D model can well take into account the end effects.

Optimal design in engineering is often constrained by a limited budget of time. The simulation models used in each field offer a good substitute for the real process to be designed, but the evaluation time of such a model is very high. In this paper a surrogate assisted multi-objective optimization algorithm is applied to solve the problem of optimal sizing of a super capacitor pack on board a tramway. The results are compared to those obtained using the NSGA-II algorithm.

Conceiving electromagnetic devices using finite element modeling tools is a complex task and also time-costly. The Efficient Global Optimization method, based on the progressive construction of surrogate models, is studied. The method uses Kriging models and allows for multiobjective optimization. An original infill criterion, combining the surrogate models and an estimate of their error is proposed. Moreover, two techniques for the calculi distribution, adapted to the algorithm, are tested on an eight-core machine. An advantage of the method consists in its capability of providing sufficiently accurate models for each objective and constraint function around the obtained Pareto front. The SMES device of the TEAM problem 22 is used as benchmark.

In this paper, traction system design in carried out with a multilevel optimiza- tion technique called Target Cascading. This methodology is based on an object- based decomposition and allows solving the problem with parallel optimizations. The large-scale system design problem is usually decomposed into several linked subproblems according to project organization structure. Target Cascading gives a new approach to formulate and to solve the complex system design optimization problem. The problem ormulation is more suitable to this kind of problem than conventional method.

Analytical Target Cascading (ATC) is a hierarchical multi-level design methodology. According to the state of the art, it is conrmed that for problems with unattainable targets, strict design consistency cannot be achieved with nite weighting factors. Then a new formulation is proposed to improve the ATC convergence. The weighted sum of deviation metric is transformed into a multi-objective formu- lation. An original optimization problem with a single global optimal solution is used as a benchmark. Thereafter an optimal design of tram traction system is used as an application example in the aim to demonstrate the robustness of the algorithm.

Surrogate-assisted single objective optimization algorithms show their advantage in low number of function evaluation. In this paper, it is extended to the case of multiobjective constrained optimization. A novel infill criteria and an improvement in constraint handling are proposed. An application to the optimal design of permanent magnet synchronous motor using finite element analysis is presented. Assisted by a surrogate models, it allows locating the non-dominated front with a low number of FEA evaluation. It provides useful information to engineer to make the trade-off decision between conflicting objectives.

Electromagnetic device implies many domains not only technical but also economical or environmental. Design of such system becomes more complex due to the interaction between each domain. This paper introduces multidisciplinary optimization (MDO). MDO is a design optimization methodology dealing the system with strong interaction. The possibility and needs in performing such kind of problem in electrical engineering application are evaluated. An electromagnetic system has been chosen and different formulations are tested. The advantages and drawbacks are discussed. The results show that MDO is a practical concept and can be applied successfully in complex electromagnetic system design.

Continuous decreasing in price of permanent magnet attracts many industries to invest in the development of permanent magnet synchronous motor, especially in traction application because of its high efficiency and compactness. In this paper a design of Surface-Mounted Permanent Magnet (SMPM) synchronous motor has been studied. The optimal design of SMPM motor can be achieved by applying a global design process and the multiobjective optimization.

The Efficient Global Optimization is applied to design an electrical machine using the finite element method. It allows searching the global optimum assisted by Kriging surrogate model of the objective function and the constraints. This method is well adapted to the optimal design using Finite Element Method while decreasing the computational time and obtaining the global optimum.

The global design method is applied to a complex system design. Ecological, economical, and technical aspect have been taking into account in order to obtain the optimal design of a rolling stock. This process has been applied to the design of a damping circuit on DC link railway traction system. The global objective is to obtain greater lifetime of capacitor. Therefore the disposal or recycling of waste could be less concerned.

The paper points out a rational methodology to design electric or hybrid drive trains components taking into account the whole system by a global approach. The aim of this global approach is to assure an optimal global solution, all components being simultaneously and conjointly designed to obtain the best adaptation to the desired system specifications. This general methodology is used to design a wheel traction motor, as a component of the global system of an electric kart drive train.

The concept of multidisciplinary optimization is applied to design an electric motor. It combines finite elements and analytical models to form together a multidisciplinary model. The different models represent different machine phenomena as electromagnetic, thermal but also vibro-acoustic. These models are linked through a constrained optimization process the entire set forming an optimal design tool.

The paper points out a new methodology to design an electric or hybrid drive train. First, the paper presents the reasons for an optimal and global approach in the process of electric drive train design. Then, the methodology is presented, detailing the considered design model as: its orientation, its structure and its characteristics. The electric vehicle design model includes a vehicle dynamic model build in a new "design way" as an energy-based model, specifications elaboration and sizing models for all drive train components. It is managed by constrained optimization techniques and allows determining the drive train components specifications for imposed vehicle performances, taking into account the dynamic behavior of the vehicle but also all components interactions. Furthermore, considering fine components sizing models, the components can be sized taking into account the whole system behavior in an optimal global design. The generic tool build up on this methodology is applied to an electric kart in order to find its optimal drive train configurations in different situations. Then the advantages and the disadvantages of these solutions are discussed, showing the interest of this approach in the decisional process of design.

A numerical computation of the force of a switched reluctance linear tubular step actuator is presented. The force is derived from the vector potential, computed by use of the finite element method, both by directly applying the Maxwell stresses formula and by derivativing the total work function at constant current with respect to the translation distance. The interaction of the two methods with the finite element meshes is studied and finally the results are compared.

Two configurations tubular linear switched reluctance step actuator with two different non-magnet separation widths are studied. The force and inductance evolution are evaluated for theses thre phase tubular motors. A magneto-dynamic model is elaborated by coupling three different models which are a magnetic, an electric and a mechanic ones. The obtained results show the influence of the non-magnetic separation width on the static and dynamic responses of the actuator.

This paper, an efficient model, taking into account the magnetic non linearity and the end effects, is achieved. It uses the measured inductances and the propulsive force characteristics modelled by artificial neural networks. The observed concordance between the simulated characteristics, obtained from the new model, and those determined by practical tests shows the efficiency of the suggested modelling approach.

A demonstration of the beneficial effects of the inserted tooth over axial AC synchronous brushless machine performances with concentred windings is done. Its influences on magnetic characteristics like flux-density and flux will be shown. The effect on the back Emf waveform will be analysed and also the impact on mechanical characteristics like synchronous torque and cogging torque. A 2D finite element model is presented and validated experimentally

Dans cette communication, est proposée une approche de modélisation visant à affiner le modèle d’un actionneur pas à pas tubulaire à quatre phases, en considérant les spécificités électriques et mécaniques de ce type d’actionneur à structure électromagnétique complexe. La modélisation des inductances statoriques et des forces développées par la machine a été effectuée par des réseaux de neurones à fonctions radiales de base et à trois couches. L’utilisation de la technique d’apprentissage par initialisation a permis d’obtenir des descriptions satisfaisantes pour les inductances statoriques et pour les forces.

The paper discusses robust optimization for electromechanical devices starting from finite element models and signal-to-noise analysis. The robustness study considering modeling and building noises is applied to the optimal structure of an axi-symmetric actuator.

An optimization process of a linear actuator and an axi-symmetric finite element model, built and used for a direct optimization of the actuator starting force, are presented in this paper. The design space exploration is carried out by the use of trellis designs, offering a significant covering of the domain and a considerable decrease of simulation number. An adaptation step is performed to comply to the need analysis.

An efficient optimal design methodology developed for electromagnetical features of switched reluctance linear tubular actuators is reported. Its different steps are presented and applied. Its implementation delivers as final output optimized and robust geometries of linear actuators with respect to imposed need analysis. The efficiency of this methodology is proved using a virtual prototype of the studied actuator and validated by practical tests. The computing tools and techniques developed in this paper are general and completely parameterized so that they can be applied to the optimal design of any device of the same type.

This paper shows how the Design of Experiments Method and particularly the Responses Surface Methodology builds polynomial models of various responses, when studying an electrical device. These polynomials are included in a global analytical design model simulating then various situations. Obvious optimization are then realized.

An optimisation software is designed on a finite element model for the description of electromagnetic systems. The optimisation process is derived from the experimental design method because this method possesses many advantages for the designer. Then, two optimisation methods are tested on two different electric motors, a brushless synchronous motor and a switched reluctance motor. Both allow to find a good optimum and to obtain information on the response sensitivity.

L’inductance de fuite est un paramètre essentiel des transformateurs HF dans les convertisseurs DC/DC isolés. Avec l’utilisation de la technologie planar et des enroulements en PCB, ce paramètre peut être réglé à une valeur prédéterminée en ajustant le positionnement des conducteurs dans la fenêtre des transformateurs. Cet article présente une étude autour de la minimisation, de la maximisation et du réglage de l’inductance de fuite d’un transformateur planar. La méthodologie développée est basée sur des simulations par éléments finis (FEM) couplées avec un algorithme d’optimisation multi-objectifs qui permettent de régler une inductance à une valeur donnée, tout en minimisant les pertes cuivre induites.

Cet article étudie des solutions permettant de remplacer les entrefers dans des inductances planar à base de noyaux E/PLT. En effet, ces entrefers, indispensables pour ajuster la perméabilité globale, engendrent des pertes supplémentaires dans les enroulements PCB. Différentes configurations basées sur l’utilisation des matériaux magnétiques à faible μ sont étudiées par simulations éléments finis 2D et comparées en termes de pertes cuivre HF et de valeur de l’inductance. Une amélioration significative des pertes cuivre HF est démontrée avec une réduction de 7 fois la résistance AC par rapport à la configuration avec entrefer.

L’objectif de ce papier concerne la problématique de dimensionnement de machines synchrones de faible puissance sous contraintes de diamètre extérieur, de couple et vitesse, de courant et de bruit émis. Une machine synchrone à aimants en surface avec un bobinage sur dents est comparée à deux machines synchro-réluctantes avec ou sans assistance d’aimants avec le même type de bobinage. L’objectif visé est de réduire le cout en essayant de conserver les mêmes performances sous contraintes. Des simulations éléments finis 3D permettent d’évaluer et de comparer les différentes structures proposées ainsi que des résultats expérimentaux. Mots-clefs : machine synchrone à aimants, machine synchro-réluctante, harmoniques de couple, harmoniques de forces radiales.

Dans le cadre du dimensionnement de chaîne de traction pour véhicules électriques, l’intégration du cycle de fonctionnement est nécessaire afin de maximiser l’autonomie du véhicule. Le nombre d’itération sur le modèle de machine est donc élevé. L’article propose un modèle de machine analytique basé sur des cartographies de flux d’axe direct et de quadrature permettant de simuler rapidement les performances d’une machine électrique sur cycle. De par l’utilisation de cartographie, le modèle magnétique peut être d’origine diverse (Éléments finis, analytique ...). Le modèle système choisi est un modèle classique de Park résolu à partir des cartographies de flux. Ce modèle orienté comportement est inversé par optimisation afin de retrouver la commande nécessaire pour obtenir les performances souhaitées.

Cette étude présente une analyse fréquentielle de la force radiale de Maxwell appliquée sur la surface interne du stator d’une machine synchrone à aimants permanents surfaciques (MSAP) à bobinage dentaire. Cette force radiale est le siège d’harmoniques spatio-temporels liés aux effets de la denture, de la saturation, de l’armature, des aimants inducteurs, et de leurs interactions. L’outil prédictif ACHFO (Analytical Calculation of Harmonics Force Orders) permet une détermination analytique de ces harmoniques spatio-temporels et plus particulièrement, l’ordre d’espace et la fréquence porteuse associée. De plus, un point important, il permet d’identifier les effets « sources » de ces harmoniques de forces à l’origine du « bruit magnétique ». Une comparaison à des simulations comportementales numériques par éléments finis (EF) mais aussi à des tests expérimentaux valideront les résultats.

L’évolution des moyens de calcul induit le déploiement de nouvelles démarches de conception. Ici, un modèle multiphysique simple est proposé pour le dimensionnement d’un moteur synchrone à aimants. La démarche consiste à associer à chaque phénomène physique le modèle le mieux approprié. Un modèle élément finis est utilisé pour représenter le comportement magnétique de la machine et un modèle analytique est utilisé pour décrire les phénomènes thermiques. Ces sousmodèles sont rassemblés au sein d’un processus d’optimisation sous contrainte nonlinéaire.

Cet article présente toute la richesse des exploitations possibles du modèle à réactance synchrone dans le cadre de la variation de vitesse. L’idée principale est de présenter les différentes stratégies de pilotage et de faire apparaître clairement les limites de fonctionnement en vitesse et en couple des moteurs synchrones à aimants. La démarche choisie est simple et progressive. Le modèle à réactance permet de pointer les grandeurs influentes et les variables permettant le contrôle du couple et de la vitesse en régime permanent.

Moteur électrique pour la propulsion des bateaux N° de publication : 2 796 775, N° d’enregistrement national : 99 09559, date de mise à disposition du public du brevet d’invention : 17 août 2001. Exploité par la société PROPELEC, créée à cette occasion.

Cet article brosse un panorama de la CAO en génie électrique. Une vision globale de la conception est d’abord introduite avant de présenter le processus itératif du prototypage virtuel avec quelques-unes des approches de modélisation classiquement utilisées pour évaluer les performances des convertisseurs électriques. L’accent est mis sur la nécessité de tenir compte de l’environnement d’utilisation du dispositif à concevoir et des différentes physiques mises en jeu ainsi que sur les stratégies d’optimisation types dans le processus de conception. Un éclairage est apporté sur les effets des procédés de fabrication, notamment pour distinguer le prototype virtuel du prototype réel. Enfin, la présentation de quelques axes de développements futurs dans le domaine de la CAO clôture l’article.