A novel three-phase multilevel inverter structure using switched capacitor basic unit for renewable energy conversion systems

Abstract

This paper presents a new three phase multilevel inverter based on switched capacitor basic units. Each phase of the proposed topology consists of a number of switched capacitor basic units and a leg of two-level voltage source inverter in cascade. The proposed topology is supplied by only one DC power supply and it has the ability to boost the input supply to the desired level. By employing simple switching strategy, capacitor voltage balancing can be achieved. A multi-carrier phase disposition pulse width modulation has been developed for switching the proposed topology. The proposed topology can generate the three phase output waveforms with less number of power supplies and semiconductor devices compared to other recently developed three phase multilevel inverters. For proving the effectiveness of the proposed topology, a seven level line to line voltage inverters is simulated in MATLAB/simulink and a laboratory prototype of the same is developed and tested for experimental investigation.