A novel family of three phase transistor clamped H-bridge multilevel inverter with improved energy efficiency

Abstract

Multilevel inverter (MLI) is a proven technology used for control of electrical machines, grid integration of renewables and active power filtering. The recent trends show ingenious attempts to achieve maximum number of output voltage levels with minimum number of active device count and active device rating. This paper proposes a novel family of H Bridge MLI with transistor clamp to increase number of output levels. The proposed topology can be easily extended to any number of voltage levels facilitating significant reduction in number of circuit components, especially active switches, and thereby improving reliability of the system. The H bridge structure enables proposed topology to achieve operation at higher voltage (HV) and higher power level without increasing the device rating. The proposed topology is modified to operate at even higher voltage levels using unique series connection of unidirectional switches. This topology is controlled by carrier based Pulse Width Modulation (CBPWM) which is easy to understand, implement and hence cost efficient. This study proposes modification in the CBPWM to reduce switching losses at higher switching frequencies and thereby improving energy efficiency of the system. The performance of proposed topology is demonstrated with extensive MATLAB/Simulink simulation studies and results are provided.