An Effective Charging-Torque Elimination Method for Six-Phase Integrated On-Board EV Chargers

This paper proposes an effective charging-torque elimination method for six-phase integrated on-board electric vehicle (EV) chargers. The integrated EV charger is derived from the power inverter, motor windings, sensors, and microchips, which can significantly reduce the system cost and volume. In fact, the charging electromagnetic torque is inevitable to produce, since the alternating currents flow through the motor windings. This is due to the motor windings serving as the filtering inductors of the rectifier for the on-board charger. In order to keep the vehicle standstill during the charging process, a universal expression of charging torque is derived and analyzed, which is according to magnetic co-energy approach. All possible charging torque elimination positions are presented with a numerical method. Moreover, the unity power factor and zero sequence current control are executed during the EV charging process. Finally, the proposed charging torque elimination method is verified by both simulation and experimentation. The results prove the validity of the proposed charging-torque elimination method for six-phase permanent magnet synchronous machine.