A modified four-step commutation to suppress common-mode voltage during commutations in open-end winding matrix converter drives

Open-end winding matrix converter drives provide a higher voltage transfer ratio and better output voltage quality with more voltage levels in the output voltage, compared to single matrix converter drives. Pulse Width Modulation (PWM) techniques have been developed for open-end winding drives to suppress switching common-mode voltage at load terminals. The switching of bi-directional switches in this converter requires a step by step control of individual IGBTs, known as four-step commutation. However, commutation can cause glitches in common-mode voltage, leading to circulating currents in the open-end winding load. These currents result in additional losses in the load. This paper presents an analysis of the common-mode voltage glitches during commutation process. A modified four-step commutation scheme is then presented that reduces these glitches, thus suppressing circulating currents in the load. Simulation and experimental results have been presented to verify the reduction in circulating currents when using the proposed modified four-step commutation technique.