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Recherche, Développement et Innovation en Génie Electrique

Séminaire, Pr. Joäo Pedro F. Trovão (University of Sherbrooke, Qc, Canada), 14 Nov. 2018

Flux weakening in high performance electric vehicles considering battery voltage variations

Prof. João Pedro F. Trovão
University of Sherbrooke, Qc, Canada
e-TESC Lab (electric – Transport, Energy Storage and Conversion Lab)
Canada Research Chair Holder

Date : Wednesday 14 November 2018, 14h00 16h00
Place : Amphi Poirier, Centrale Lille


With rapid electrification of transportation, it is becoming increasingly important to have a comprehensive understanding of criteria used in powertrain selection (battery, drive and motor). This presentation presents a comparative study regarding two equivalent battery pack designs for a high-performance electric vehicle (EV). On one hand, increasing the DC bus voltage is thought to improve overall powertrain efficiency, but on other hand, the flux weakening scheme is generally adopted for traction motors to achieve a wider speed range where the common proportional and integration compensator is needed to regulate the flux-producing current. However, the regulator performance deteriorates due to dc-link voltage disturbances and motor parameter nonlinearities in the different speed regions. To evaluate this issue, a powertrain model based on energetic Macroscopic Representation (EMR) coupled to a traditional flux weakening algorithm is studied for a high-performance EV using a low-voltage PMSM motor and two equivalent battery pack designs. The augmented prediction state relationship between stator voltage and flux-producing current is established for motor current control. The overall closed-loop control, deduced by direct inversion of the vehicle EMR, is presented where the system eigenvalues are adjusted for various speed regions, and accordingly, the battery packs performance can be evaluated. Moreover, a weight coefficient can be adjusted corresponding to speed variation for guaranteed motor control performance. The simulation results are provided to verify the model based on EMR and clearly indicate that at constant and higher bus voltage will improve powertrain efficiency in some, but not all, operating conditions.

About the Speaker

João Pedro F. Trovão (S’08 – M’13 – SM’17) received the M.Sc. degree and the Ph.D. degree in Electrical Engineering from the University of Coimbra, Coimbra, Portugal, in 2004 and 2013, respectively. From 2000 to 2014, he was a Teaching Assistant and an Assistant Professor with the Polytechnic Institute of Coimbra–Coimbra Institute of Engineering (IPC–ISEC), Portugal. Since 2014, he has been a Professor with the Department of Electrical Engineering and Computer Engineering, University of Sherbrooke, Sherbrooke, QC, Canada, where he holds the Canadian Research Chair position in Efficient Electric Vehicles with Hybridized Energy Storage Systems. His research interests cover the areas of electric vehicles, hybridized energy storage systems, energy management and rotating electrical machines. J. P. F. Trovão was the General Chair of the 2018 IEEE Vehicle Power and Propulsion Conference, Chicago, US. He was a Guest Editor for the Special Issue of IET ELECTRICAL SYSTEMS IN TRANSPORTATION ON ENERGY STORAGE AND ELECTRIC POWER SUB -SYSTEMS FOR ADVANCED VEHICLES . He was a Guest Editor for the Special Issue of IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY ON ELECTRIC POWERTRAINS FOR FUTURE VEHICLES.