Hybrid DC-Bus Capacitor Discharge Strategy Using Internal Windings and External Bleeder for Surface-Mounted PMSM-Based EV Powertrains in Emergency

When electric vehicles (EVs) encounter an emergency, the voltage of dc-bus capacitor in surface-mounted permanent magnet synchronous motor (SPMSM)-based powertrain requires to be reduced as fast possible. In order eliminate disadvantages and synthesize advantages traditional machine-winding-based external bleeder-based discharge techniques, this article proposes a hybrid strategy that can achieve 5-s minimum sacrifice bleeder size weight for any EV drives. For purpose evaluating reduction new method, individual scheme is modeled analyzed at first. Then, combined method developed, which contains two sequential procedures: bleeding resistor (BR) design control algorithm design. The BR process has implemented under extreme condition. But concerning emergency might occur moment when machine operates below maximum speed, three different modes including full-power, partial-power, are developed. proposed techniques verified by experiments conducted on three-phase SPMSM drive system used EVs.