A Battery/Supercapacitor Hybrid Powered EV SRM Drive and Microgrid Incorporated Operations
Min-Ze Lu, Zhi-Wei Guo, C.M. Liaw
Abstract
This article presents a battery/supercapacitor (SC) powered electric vehicle (EV) switched-reluctance motor (SRM) drive and its microgrid incorporated operation control. The battery and the SC are connected to the motor drive dc-link via an H-bridge converter and a one-leg boost–buck converter, respectively. The varied dc-link voltage can be set lower and higher than the battery voltage to yield the improved EV driving performance over a wide speed range. Through the proposed current sharing control approach for the battery and SC, the battery can possess smooth discharging current characteristics. The SC is arranged to be charged by the battery during constant speed driving duration to preserve sufficient energy. In the proposed EV SRM drive current control scheme, the feedback controller is augmented with an observed back electromotive force (EMF) feedforward controller and a robust current tracking error cancellation controller. More importantly, for EV, the commutation shifting and the voltage boosting are applied to reduce the effects of back EMF on the current control under higher speeds and/or heavier loads. The regenerative braking is successfully conducted. Similarly, the speed dynamic control is also enhanced by adding robust control. As to the microgrid incorporated operation, the EV SRM drive can perform the microgrid-to-vehicle (M2V) and vehicle-to-microgrid (V2M) operations to dc microgrid. The required schematics are formed using the embedded converters in the EV drive or the microgrid. Successful operations are verified experimentally.