Individual information
Hussein ZAHR | ||
Titre | Post-Doctorant | |
Equipe | Commande | |
Adresse | Arts et Métiers ParisTech - Campus Lille 8, boulevard Louis XIV 59046 LILLE CEDEX | |
Téléphone | +33 (0)3-20-62-22-10/Ext:2254 | |
hussein.zahr@ensam.eu | ||
Observation / Thématique de recherche | Machines électriques polyphasés. | |
Publications |
International Journals |
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[1] Design Considerations of Five-Phase Machine with Double p/3p Polarity IEEE Transactions on Energy Conversion, 06/2018, URL, Abstract GONG Jinlin, ZAHR Hussein, SEMAIL Eric, TRABELSI Mohamed, SCUILLER Franck, ASLAN Bassel |
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 |
[2] Comparison of optmized Control Strategies of a Bi-harmonic five-phase Electrical Machine for Traction high speed range Energies, Vol. 9, N°. 12, pages. 952, 11/2016, URL, Abstract ZAHR Hussein, GONG Jinlin, SEMAIL Eric, SCUILLER Franck |
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. |
[3] Maximum reachable torque, power and speed for five-phase SPM machine with low armature reaction IEEE Transactions on Energy Conversion, Vol. 31, N°. 3, pages. 959 - 969, 03/2016, URL, Abstract SCUILLER Franck, ZAHR Hussein, SEMAIL Eric |
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. |
International Conferences and Symposiums |
[1] Homopolar Current’s Copper Losses Analysis for Different Modulations in Open-End Winding Five-Phase drives International Conference on Electrical Machines (ICEM, 2018), 09/2018, Abstract DOS SANTOS MORAES Tiago José, TRABELSI Mohamed, ZAHR Hussein, SEMAIL Eric |
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. |
[2] 3D MULTI-NODAL THERMAL MODELLING OF A FIVE-PHASE MACHINE
WITH IRREGULAR LOSSES DISTRIBUTION Twenty-fifth Symposium on Electromagnetic Phenomena in Nonlinear Circuits (EPNC 2018), 06/2018, Abstract OUENZERFI Safouene, ZAHR Hussein, TRABELSI Mohamed, BOUBAKER Riadh, SEMAIL Eric, HARMAND Souad |
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. |
[3] Comparison and Analysis of Post-Fault Operation Modes in a Five-Phase PMSM Considering Thermal Behavior 2018 IEEE CPE-POWERENG, Doha-Qatar, 04/2018, URL, Abstract ZAHR Hussein, TRABELSI Mohamed, SEMAIL Eric |
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. |
[4] Five-Phase Bi-Harmonic PMSM Control under Voltage and Currents Limits IECON 2017, 43rd Annual Conference of the IEEE Industrial Electronics Society, 10/2017, Abstract ZAHR Hussein, TRABELSI Mohamed, SEMAIL Eric, NGUYEN Ngac Ky |
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 |
[5] A bi-harmonic five-phase SPM machine with low ripple torque for marine propulsion 2017 IEEE International Electric Machines and Drives Conference (IEMDC), 05/2017, Abstract SCUILLER Franck, ZAHR Hussein, SEMAIL Eric |
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. |
[6] Five-phase SPM machine with electronic pole changing effect for marine propulsion 2016 International Conference on Electrical Systems for Aircraft, Railway, Ship Propulsion and Road Vehicles & International Transportation Electrification Conference (ESARS-ITEC), Toulouse, France, 11/2016, Abstract ZAHR Hussein, SCUILLER Franck, SEMAIL Eric |
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 |
[7] Maximum Torque Per Ampere Strategy for a Bi-harmonic Five-phase Synchronous Machine SPEEDAM, 06/2016, Abstract ZAHR Hussein, SCUILLER Franck, SEMAIL Eric |
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. |
[8] Five-phase version of 12slots/8poles three-phase Synchronous Machine for Marine-propulsion. IEEE-Vehicle Power and Propulsion Conference VPPC,Coimbra,Portugal, 10/2014, Abstract ZAHR Hussein, SCUILLER Franck, SEMAIL Eric |
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. |
National Conferences and Symposiums |
[1] Paramètres clés pour la conception d’une machine pentaphasée à aimants à double polarité Symposium de Génie Electrique, Cachan, France., 07/2014, URL, Abstract ZAHR Hussein, SCUILLER Franck, SEMAIL Eric |
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. |
Invited Conferences |
[1] Different Possibilities of Multiphase Drives Functioning in Constant Power Region IEEE 2nd International Electrical and Energy Conference (CIEEC 2018), 11/2018, URL NGUYEN Ngac Ky, ZAHR Hussein, VU Duc Tan, SEMAIL Eric |
PhD Thesis |
[1] Machine pentaphasée à double polarité pour électrification du domaine de transport par effet de boite de vitesse électromagnétique Thèse Arts&Métiers ParisTech, 12/2016, URL, Abstract ZAHR Hussein |
Les machines électriques à aimants, appréciées pour leurs densités énergétiques
volumique et massique, équipent la majorité des véhicules électrifiés. Par contre, dans la zone à
puissance constante d’un système de propulsion, les commander à pertes maîtrisées, cela en
démagnétisant les aimants mais de façon réversible, reste une gageure, particulièrement sous
environnement thermique changeant. Les solutions simples pour se prémunir d’une
démagnétisation irréversible sont coûteuses: surdimensionner ou ajouter une terre très rare
(Dysprosium).
Cette thèse propose d’ajouter à l’approche de la démagnétisation réversible
universellement utilisée, celle d’une boite de vitesse électromagnétique. Pour cela on conçoit
une machine pentaphasée à aimants.
Passer de trois à cinq phases permet alors d’augmenter les paramètres de réglage de
l’alimentation électrique et, moyennant approximation, de disposer de deux machines fictives à
p et 3p paires de pôles, chacune pouvant contribuer de façon équivalente à la production du
couple. Pratiquement, l’utilisation optimale de ces deux machines permet de reconstituer la
fonction de boite de vitesse. |
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