A dual source switched-capacitors multilevel inverter topology with extended voltage levels and voltage gain

Abstract

The switched-capacitors multi-level inverters (SCMLI) are widely used in renewable energy resources for enhancing the quality and reliability of generated power. This paper suggests a new topology of extendable voltage levels and voltage gain units using switched capacitors SC with a dual DC source. The proposed unit can be extended by a modular pattern to increase the output voltage levels and voltage-boosting gain of the inverter. The main feature of this work is presenting a unit topology that utilizes multiple and modular sub-cells to increase the voltage gain at the output by increasing the number of the sub-cell components. A ternary relationship of the voltage magnitudes between the two asymmetrical DC sources is mandatory. Furthermore, all the capacitors are self-balanced, so there is no need for any additional and complex control circuit. Moreover, to decrease the cost factor of the inverter, a low IGBT switch count is taken into consideration and no passive diodes are used in the proposed structure. The H-bridge is connected to the unit to achieve bipolar voltage at the output. The operational analysis of the inverter is delineated in detail. A comparative study with state-of-art MLIs in different terms such as the number of components, the total standing voltage, the cost factor, and the gain shows the particularity of the proposed topology. The simulation of the proposed MLI is performed using PSCAD-EMTDC software. An experimental prototype is built to validate the simulation results.