Improved Power Converter of SRM Drive for Electric Vehicle With Self-Balanced Capacitor Voltages

The regulation of phase currents is bound by the voltage of power source for switched reluctance motor (SRM) drive with conventional asymmetric half-bridge (AHB) power converter in electric vehicle (EV). To avoid the drawback, an improved active boost power converter with self-balanced capacitor voltages is proposed. First, the problems existing in the AHB power converter are analyzed in different stages of each phase current. Then different working modes of the proposed converter are investigated. The corresponding control strategies are implemented in the light of two conduction sequences. The reference phase voltage is obtained with a new method. Then the control signals of the front-end topology are generated by comparing the reference phase voltage with the required value. One significant advantage of the proposed converter is that it can provide different voltages according to the operation condition of SRM dynamically. The other is that the maximum phase voltage the converter can boost is up to three times the supplied voltage. Comparative experiments on a three-phase 12/8 SRM drive validate the performance of the converter and the effectiveness of the control strategies.