Integrated Power Converter with G2V and V2G capabilities for 4-Phase SRM Drive Based EV Application

The article presents an integrated power converter (IPC) for EV (electric vehicle) application employing 4-phase switched reluctance machine (SRM) drive. In the discussed IPC an improved miller converter, and a bidirectional converter reconfigured on-board battery charger/discharger is integrated. During driving mode, an improved miller converter is reconfigured from the IPC, and the battery energy storage system (BESS) supplies driving power for SRM. When EV is in idle condition, the employed IPC is reconfigured as a cascade connection of bidirectional DC-DC and bidirectional AC-DC converter, performing two functions. (1) During battery charging, i.e., grid-to-vehicle (G2V), the bidirectional AC-DC converter exhibit characteristics of a single-phase bridgeless boost power factor correction circuit (PFCC). The buck type DC-DC converter in cascade achieves constant current/ constant voltage charging of BESS. (2) During battery discharging, i.e., vehicle-togrid (V2G), the boost type DC-DC converter boosts the BESS voltage. And the bidirectional AC-DC converter exhibit characteristics of a single-phase voltage source inverter (VSI). For realizing the charging inductors during G2V/V2G charging, 4-phase SRM phase windings are used. Thus, the proposed IPC without any off-board circuit is capable of charging/discharging BESS at AC grid voltage. Also, the control technique ensures zero net torque production during the charging/discharging process.

I. Introduction

The battery energy storage system (BESS) plays a vital role in developing electric vehicle (EV) technology. The efficiency and lifetime of employed BESS depend on how efficiently the BESS is charged/discharged. In this regard, battery chargers play a vital role in the development of EV technology. The BESS can be charged via AC or DC battery chargers. However, due to the limited DC charging infrastructure, generally, present-day EVs are equipped with on-board battery chargers capable of charging BESS directly from a standard AC outlet [1].