Performance enhancement of electric vehicle traction system using FO-PI controller

Abstract

This work improves the performance of an electric vehicle (EV) traction system by using non-linear fractional-order proportional–integral (FO-PI) controller. The functionality of FO-PI controller is benchmarked against integer-order proportional–integral (IO-PI) controller. A 400 V, 6.6 Ah Li-ion battery bank is designed to power an indirect field-oriented induction motor driven prototype EV traction system. The appeal of this study is to reveal the simplicity, robustness, and effectiveness of FO-PI speed regulator for EV traction system. The efficacy of FO-PI speed regulator for EV applications is validated through rigorous experimentation. The FO-PI controller due to its non-linear nature proves to be more robust and effective under variation of a system's parameters and external disturbances as compared to IO-PI controller. Furthermore, the experimental results show that FO-PI control strategy provides higher torque per amp output while maintaining better voltage and state-of-charge profiles of the Li-ion battery bank.