Direct parallel operation of cascaded H-bridge multilevel inverters

This paper proposes a method to parallel m digital controlled cascaded H-bridge (CHB) multilevel inverters directly with high bandwidth current sharing capabilities. The proposed method utilizes switch signal synchronization with dead time control to eliminate circulating current and adopts “piecewise” master-slave strategy to achieve equal current distribution in less than one cycle. A prototype is designed, built, and tested to verify the proposed method.