When electric vehicles (EVs) encounter an emergency, the voltage of the DC-bus capacitor in the surface-mounted permanent magnet synchronous motor (SPMSM) based powertrain requires to be reduced as fast as possible. In order to eliminate the disadvantages and synthesize the advantages of the traditional machine winding-based and external bleeder-based discharge techniques, this paper proposes a hybrid discharge strategy which can achieve five-second discharge in minimum sacrifice of the bleeder size and weight for any EV drives. For the purpose of evaluating the size reduction of the new method, the individual bleeder-based scheme is modelled and analyzed at first. Then, the combined discharge method is developed, which contains two sequential procedures: bleeding resistor (BR) design and discharge control algorithm design. The BR design process has to be implemented under the extreme condition. But concerning that the emergency might occur at the moment when the machine operates below the maximum speed, three different discharge modes including full-power, partial-power and bleeder-based discharge modes are developed. The proposed discharge techniques are verified by experiments which are conducted on a three-phase SPMSM drive system used for EVs. 7
CORE (COnnecting REpositories)
CORE (COnnecting REpositories)