Review of Torque Cancellation Methods for Integrated Motor Drive and Charger System

The power level of on-board charger (OBC) is limited by its cost and space occupation. Although the power density of OBC can be improved by system integration or applying wide bandgap power semiconductor device, the power level is still limited to 22 kW. Using the drivetrain of EV to constitute the AC/DC rectifier stage of OBC can save “half” the space of OBC. Therefore, the OBC will only need isolated DC/DC converter stage so that the power level will be improved a lot. The crux of integrated motor drive and charger system (IMDCS) is how to eliminate the motor torque in charging mode. This paper reviews and compares the existing torque cancellation methods. Furthermore, the essences of those methods are analyzed and classified. Finally, simulations and experiments results are used to verify the point of this paper.