Pre- and Post-Fault Operations of Six-Phase Electric-Drive-Reconstructed Onboard Charger for Electric Vehicles

Abstract

The concept of electric-drive-reconstructed onboard charger (EDROC) potentially opens the door to harness the existing drivetrain in electric vehicle (EV) to do the job of battery charger, thus performing a remarkable value in commerce. In this article, the pre- and post-fault operations of an EDROC are studied, which incorporates an asymmetrical six-phase permanent magnet synchronous machine (ASPMSM) drive. At first, the decomposed currents of the machine in healthy and faulty cases are solved and their trajectories are depicted, indicating that a rotating field will exist if an open-phase fault (OPF) occurs. Afterward, a rotating field cancellation scheme based on the minimum copper loss criterion is proposed by rearranging stator currents, with two constraints under consideration that are responsible for generating pulsating field and balanced grid currents, respectively. Following this, a control scheme shared for both pre- and post-fault conditions is proposed, where the carrier-based modulation without any zero-sequence signal injection is employed. Finally, the proposed rotating field cancellation scheme is verified by experimental results.