Drive control strategy for plug-in hybrid electric vehicle system based on modular multilevel converter

Abstract

A power conversion system for plug-in hybrid electric vehicles (PHEV) based on "back-to-back" modular multilevel converter(BMMC) is proposed to solve the problem that the traditional MMC-EV can only work with one motor. The power flow of BMMC system with two motors is complex and no one has ever studied it. The state of charge (SOC) balance control strategy of the integrated power converter is studied in various driving modes by this paper. Based on the bridge arm current control, this strategy combines the vector control of permanent magnet synchronous motor(PMSM) with the hierarchical SOC equalization control, realizes the high performance drive control of PHEV system, and high-efficiency power transfer and management among motor, generator and battery, and avoids the battery and energy loss caused by the redundant charge and discharge process. At the same time, it is convenient to switch freely between different driving modes. The correctness and feasibility of this control strategy are verified through RT-LAB real-time simulation.