A novel reduced switch count multilevel AC/AC converter

Despite all the unique features multilevel converters offer, their high number of required power switches has restricted their implementation to particular applications. To mitigate this problem, a novel multilevel ac/ac converter is proposed in this paper which utilises less number of semiconductor devices in its structure. The proposed converter is achieved by cascading recently introduced reduced switch count ac/ac converter and is comparable in performance to cascaded h-bridge multilevel converters except that it is an ac/ac converter capable of working in regenerative mode. The proposed configuration retains all the features of CHB MLIs such as low output voltage distortion, reduced dv/dt stresses, low distortion input ac current and modular structure. Moreover, compared to conventional CHB converters, the number of switches and related drive circuits are reduced in the proposed converter by 25%. The novel structure is introduced, its generalized carrier based modulation scheme is elaborated and a control method is suggested for it. The validity of operation of the proposed system is verified through simulation.