Space vector modulation of dual inverter with battery and capacitor across DC buses

A space vector modulation (SVM) technique of a dual inverter system feeding a three-phase motor with open-end-windings is proposed in the paper, where one of the inverters has a battery power source and the other has a capacitor across the DC bus. The SVM must be achieved both to operate the motor with field-oriented control and to control the capacitor voltage at a half value of the battery by using redundant switching states at the same time. The control of the capacitor voltage is carried out by alternating a charging or a discharging mode in each switching state, taking relative phase angle between the motor voltage vector and the motor line current vector into account. In other words, it is necessary to select an optimal switching state among various redundant states which makes the capacitor voltage follow its command properly, considering the instantaneous motor power factor. The paper demonstrates an experimental setup and test results as well as computer simulation results.