A Fast On-Board Integrated Battery Charger for EVs Using an Asymmetrical Six-Phase Machine

Abstract

The paper considers a novel fast charging topology for electric vehicles (EVs). Instead of being made as a separate unit, the proposed on-board charger utilizes power electronics components that already exist inside the vehicle, namely an asymmetrical six-phase propulsion motor and a six-phase inverter. The charger can operate at unity power factor, and is capable of vehicle-to-grid (V2G) operation as well. Additional degrees of freedom of the six-phase machine are employed in order to transfer a part of excitation from the torque producing to non-torque/flux producing plane of the machine. Consequently, electromagnetic torque is not produced in the machine during the charging/V2G process, so that the rotor does not have to be mechanically locked. A theoretical analysis of the operating principles is reported, and simulation results are given for both charging and V2G mode of operation.