Five-phase SPM machine with electronic pole changing effect for marine propulsion

In this paper, the possibility of designing a fivephase Surface-mounted Permanent Magnet (SPM) machine 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

Comparison and Analysis of Post-Fault Operation Modes in a Five-Phase PMSM Considering Thermal Behavior

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

A bi-harmonic five-phase SPM machine with low ripple torque for marine propulsion

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, this last feature being the scope of the paper. 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, thus being obtained with a simple control strategy that aims at achieving constant currents in the rotating frames. The time simulations of the drive confirm the significant reduction of the speed oscillation, especially at low speed

Comparison of Optimized Control Strategies of a High-Speed Traction Machine with Five Phases and Bi-Harmonic Electromotive Force

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 (E1) and third (E3) 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 his 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

Five-Phase Bi-Harmonic PMSM Control under Voltage and Currents Limits

For a particular five-phase synchronous machine, this paper investigates the sensitivity of a vectorial control strategy on the required peak phase voltage whose value is fundamental for the choice of the DC bus voltage. The specificity of the machine is that the first and third harmonic components of the back electromotive force (back-emf) have the same amplitude. As a consequence, the torque can be produced by one of them or both with suitable currents. This degree of freedom is interesting for optimizing the efficiency and generating high transient torque. However, using two harmonics having the same amplitude leads to a necessity to analyze the constraints on the required phase machine voltage. Considering a Maximum Torque Per Ampere (MTPA) strategy, the paper examines the impact of some parameters such as the phase shift between currents and back-emfs or the ratio between the third and the first harmonic of current on the torque and maximum voltage value. Experimental tests with a limited DC bus voltage have been carried out and compared to the results obtained by a Finite Element Analysis

Homopolar Current’s Copper Losses Analysis for Different Modulations in Open-End Winding Five-Phase drives

This work has been achieved within the framework of CE2I project. CE2I is co-financed by European Union with the financial support of European Regional Development Fund (ERDF), French State and the French Region of Hauts-de-France.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. Accordingly, different modulation strategies are compared with the goal of reducing the homopolar current and, consequently the resulting copper losses. The comparison study is achieved using Matlab/Simulink and a finite element model in order to evaluate these losses.European Regional Development Fund (ERDF

Machine Pentaphasée A Double Polarité Pour Electrification Du Domaine Des Transports Par Effet Boite De Vitesse Electromagnétique

Permanent Magnet electrical machines , appreciated for their high power density, equip the majority of the electrified vehicles. However, controlling these machines, in the constant power range of the propulsion system while mastering the losses, with PM reversible demagnetization remains a challenge especially under varying thermal environnement. Proposed solutions aim for protecting PM from irreversible demagnetization are costly: oversizing or using very rare earth PM (Dysprosium).In this thesis, we proposed to add on the reversible demagnetization approach universally used , that of a electromagnetic gearbox. Thus, we design a five phase PM machine.Increasing the phase number from three to five, increases the adjustment parameter of the electrical supply, and allows to have two fictitious machines with p and 3 p poles. Each fictitious machine contributes equivalently in producing torque. Practically, the optimal use of these two machines leads to reconstructing the gearbox function.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 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

Double polarity five-phase machine for eleification of transportation by a kind of electromagnetic gearboxctr

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 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.Permanent Magnet electrical machines , appreciated for their high power density, equip the majority of the electrified vehicles. However, controlling these machines, in the constant power range of the propulsion system while mastering the losses, with PM reversible demagnetization remains a challenge especially under varying thermal environnement. Proposed solutions aim for protecting PM from irreversible demagnetization are costly: oversizing or using very rare earth PM (Dysprosium).In this thesis, we proposed to add on the reversible demagnetization approach universally used , that of a electromagnetic gearbox. Thus, we design a five phase PM machine.Increasing the phase number from three to five, increases the adjustment parameter of the electrical supply, and allows to have two fictitious machines with p and 3 p poles. Each fictitious machine contributes equivalently in producing torque. Practically, the optimal use of these two machines leads to reconstructing the gearbox function