High resolution m-cell symmetric cascaded H-Bridge multilevel inverter with one transistor clamped H-Bridge per phase

A high resolution m-cell Symmetric Cascaded H-Bridge Multilevel Inverter (SCHB-MLI) based on cascade connection of one 5-level Transistor Clamped HB (TCHB) power cell and (m-1) 3-level HB power cells is proposed in this paper. The proposed hybrid converter features reduced number of components, reduced number of redundant switching states, and near equal power distribution among the power cells. Operation of proposed converter is explained using Staircase modulation technique and Hybrid PWM technique for 9-level converter and, Hybrid PWM technique for 13-level converter. The analysis of dc link midpoint current of TCHB power cell is also presented. Finally the operation of proposed converter system is verified by simulation results for 9-level converter with 500 hp induction motor as load.