Dominique Lhotellier

Design of an Axial-Flux Interior Permanent-Magnet Synchronous Motor for Automotive Application: Performance Comparison with Electric Motors Used in EVs and HEVs

The use of permanent-magnet (PM) machines for electric vehicles (EVs) and hybrid electric vehicles (HEVs) has grown substantially in recent decades. This is due to their high torque/power performances, especially when rare-earth PMs are used. Furthermore, high efficiency and, with adequate control, large speed operation range can be reached. In this paper, an axial-flux (AF) machine type interior PM (IPM) is designed to be used in HEV application. Machine performances will be described and compared to those of conventional IPM motors used in current commercialized EVs and HEVs.

Design by optimization of an axial-flux permanent-magnet synchronous motor using genetic algorithms

In this paper, a genetic algorithm (GA) is used to optimize a motor for an automotive application. This motor is a double stator axial permanent-magnet (PM) machine, and the optimization uses a simplified analytical model. The solution obtained with the tool is compared to three-dimensional (3-D) finite-elements method (FEM) to confirm the validity of the model.

Modeling of a coaxial magnetic gear equipped with surface mounted PMs using nonlinear adaptive magnetic equivalent circuits

This paper presents a nonlinear adaptive magnetic equivalent circuit (MEC) of a coaxial magnetic gear (MG). High speed (HS) and low speed (LS) rotors are equipped with surface mounted PMs. The stationary ring (SR) located between the rotors is constituted by magnetic iron pieces which create the flux modulation. Using the MEC, the magnetic flux density is calculated in the different parts of the MG, as well as the stall torque. In order to evaluate the reliability of the proposed model, the results are compared to 2-D finite-element analysis (FEA).

Electromagnetic, mechanical and thermal analysis of a high-speed surface-mounted PM machine for automotive application

This paper deals with the performance analysis of a high-speed (HS) permanent magnet (PM) machine for an automotive application. Electromagnetic performances in terms of torque, power and losses have been calculated. In order to reduce PM eddy-current losses, tangential and axial segmentation have been studied. Besides electromagnetic performances, the mechanical integrity of the rotor has been analyzed. In this paper, a retaining PM sleeve made of carbon fiber is used in order to withstand the centrifugal force, and the mechanical stress has been calculated using structural finite-element. Furthermore, due to high transient current density and rotor losses, the thermal behavior of the machine has been studied for transient operating points. The obtained results show that the rotor mechanical integrity is ensured and the temperature increase is acceptable.

Selection of rare-earth-free permanent magnet machine for C-segment electric vehicle: Comparative analysis of different machine topologies

This paper deals with rare-earth-free permanent magnet traction machine design for C-segment electric vehicle (EV). Four different ferrite permanent magnet synchronous machine topologies having different magnets arrangement and pole-pair number, selected for their high potential, are presented and compared thanks to a computationally efficient finite-element based analysis tool that was developed purposely. It was found that flux focusing machine having 12 poles and 72 slots outperforms in terms of torque-speed requirement fulfillment, efficiency and power to weight ratio. Influence of the magnet grade on the resilience against demagnetization under symmetrical short-circuit condition of the selected machine was then investigated. It is shown that the machine is subject to complete demagnetization if low grade hard ferrite (Ceramic 8) is adopted, thereby fostering research of new and abundantly available magnet grades is key for penetration of new and cost effective electrical machines into EV powertrain market.

Dynamic electric model for IGBT power module based on Q3D® and Simplorer®: 3D Layout design, stray inductance estimation, experimental verifications

The layout of power modules is one of the key points in power module design, especially for high power densities, where couplings are increased. Stray inductances cause various problems in switching devices and should be minimized at an early design stage to avoid later required countermeasures and redesign after the device prototype has been built. In this paper, using Ansys® Q3D® Extractor, electromagnetic simulation is carried out to extract and evaluate the inductive and resistive parasitics of one phase of a three-phase automotive inverter module with rating of 650 V–400 A. The purpose is to develop and verily the electrical model including parasitic parameters for the studied phase-leg operating as a chopper. The switching behavior of the studied structure is analyzed based on Ansys® Simplorer® simulation, and a dynamic electrical model is carried out. Experimental test measurements are performed. The comparison between the simulation models and the experimental data is reported and conclusions are made.

Analysis of ferrite assisted synchronous reluctance machines for medium sized electric

Hard Ferrite Assisted Synchronous Reluctance Machines (FASRM) with 6, 8 and 10 poles are analyzed and compared in terms of torque production capability and quality along the entire torque/speed envelope, converter rating and capability to withstand transient short-circuit demagnetizing field. A generic low computational time analysis tool was developed. Medium sized personnel vehicle traction requirements were considered for comparison of the designed machines. It is found that 6-pole machine outperforms the others with regard to peak torque per ampere while 10-pole (flux concentration topology) is best for constant power operation, i.e. flux weakening capability.