A space vector modulation for a low zero-sequence voltage output

A space vector PWM (SVM) algorithm is designed to prevent zero-sequence currents between tandem inverters in three phase applications. The development is motivated and illustrated by a GTO/IGBT inverter system, feeding a large three phase motor. In applications where harmonic emissions are highly undesirable, the low power/fast switching IGBT is used to cancel the GTO low frequency current ripple. Stray zero-sequence currents between inverters may saturate the IGBT and should thus be prevented. This requires a customized SVM in the GTO, which is presented here.