Novel Symmetric and Asymmetric Multilevel Inverter Topologies With Minimum Number of Switches for High Voltage of Electric Ship Propulsion System

Abstract

Multilevel inverters are the excellent solution to attain speed range from minimum to maximum with high torque at the propeller shaft in electric ship propulsion system. To produce high voltage with less harmonic content, multilevel inverter requires more number of switching devices. In this paper, a new topology for symmetric, asymmetric multilevel inverter is proposed. Hybrid topologies are extracted from proposed topologies for operating in higher voltage levels. It generates dc voltage levels analogous to conventional topologies with less number of switches. It results in the reduction of switching losses, complexity and converter cost. The effectiveness of the suggested topologies are verified by simulation using MATLAB/SIMULINK. From the proposed topologies, asymmetric multilevel inverter is experimentally verified with simulation results. By proper selection of switches in the proposed topologies, it is possible to supply power to the ship propeller with maximum efficiency.