Analysis and operation of an integrated battery charger using the EV traction motor as filter

Abstract

This paper presents an operation mode for an onboard integrated battery charger (IBC) which uses the electric vehicle (EV) traction motor as input filter in the battery charging mode. The studied charger adds few components to the already existing power electronics employed for propulsion. By connecting the single-phase mains to the traction inverter, only two mechanical switches or solid state relays are necessary to configure the same converter to operate as a battery charger. The proposed operation mode for this IBC reduce and distribute the inverter losses during charging operation mode. Furthermore, a machine analysis is presented to characterize the machine behavior considering the single-phase input current flowing through the three-phase traction motor. Although the IBC is best suited for an induction motor (IM) application, an analysis of the feasibility of using a permanent magnet (PM) motor is realized. Simulation results are presented which validates the functionality of the proposed charger operation.