Investigation of bidirectional quasi Z-Source inverter for BLDC drive with modified shoot-through hysteresis current control in low power EV applications

Abstract

Abstract Research and development concerning the electrification of the easily affordable two-wheel vehicle segments operating at low power capacity are significant for a highly populated country like India to attain sustainable transportation. Hence, a novel approach is proposed in this paper focussing on the investigation of bi-directional quasi-Z source inverter (BD-qZSI) using a modified shoot through hysteresis current control (STHCC) loop for brushless direct current (BLDC)-motor-based low power electric vehicle (EV) applications to address this issue. The practical vehicle dynamics, without the computational burden of the complete drive cycle. are suitably established in this research work by achieving different speed and torque conditions with the inclusion of five different modes of operations consisting of three motoring modes (eco, coast, and wrap) and two regenerative braking modes (soft regen and hard regen). The combination of the closed loop speed control of BLDC motor involving PI control in cascade with modified STHCC for the operation of BD-qZSI is analysed in MATLAB/Simulink environement. The performance of the bidirectional power transfer in a single stage including regenerative braking is examined. The results confirm the validity of the proposed system for low-power EV applications. The modified STHCC is easy to implement with quick response compared to other control methods. The performance of single stage BD-qZSI is superior to the conventional two stage converter topologies and to that of Z source inverters. The commutation ripple observed in the torque profile is insignificant in low-power BLDC drive applications. The overall drivetrain efficiency of 84.82% is achieved at rated load condition.