Dynamic Control of Traction Motor for EV Fed via Dual Source Inverter with a Two Battery System

Abstract

An electric vehicle uses multiple energy-storage systems to power the traction motor. Dual-source inverters (DSIs) are used for single-stage power conversion by skipping the dc/dc boost converter stage; therefore, eliminating the passive magnetic storing element which improves the overall efficiency of the drive; moreover, multiple energy-storage systems improve the power density of the system. This article discusses the fine control of a traction motor from zero speed to rated speed supplied through a dual-source inverter. Field-oriented control with space vector modulation technique is applied to achieve closed-loop control. Two dc sources are used, one having a higher-voltage battery and one a lower-voltage battery. The higher-voltage battery is the main battery which supplies power to the traction motor, whereas the lower-voltage battery supplies power to supplementary loads of the EV. This article presents improved dynamic behaviour of an induction-motor-driven EV fed from a dual-source inverter using modified closed-loop field-oriented control with space vector modulation. The improvement includes reduced control complexity due to space vector modulation and achieving the option of EV operation in an emergent situation using the same converter and control system. The simulated performance of the presented system is obtained in MATLAB/Simulink. A step-down experimental prototype is used for verification of effective control of the induction motor as the EV is under constant torque variable speed operation with real-time parameters such as power, power factor, current harmonics, and voltage/current stresses across the switch using two batteries individually.