Postfault Operation of Onboard Integrated Battery Charger via a Nine-Phase EV-Drive Train

This article presents the operation of onboard integrated battery chargers tied to a nine-phase EV-drive train, shedding light on the charging performance during the postfault operation, when one or more faulty inverter legs are disconnected. The objective in that case is to ensure balanced grid currents, while maintaining minimum machine losses at zero average torque production. The proposed concept requires a minimalistic change from a control structure perspective to switch between the pre- and postfault cases. Limitations and fault cases are discussed and corroborated with experimental tests on a 1.5-kW prototype.The derived concept is parameter independent and applicable to nine-phase drives, irrespective of the type of rotor used.