ASYMMETRICAL CASCADED H-BRIDGE MULTILEVEL INVERTER WITH REDUCED POWER SWITCHES

摘要

Present invention relates to a seven level asymmetrical cascaded H-bridge multilevel inverter with switched series-parallel DC sources is disclosed. At least two DC voltage sources along with polarity generation circuit are used. The invention uses a multi carrier pulse width modulation (PWM) technique for a cascaded H-bridge multilevel inverter with reduced number of switches developed by asymmetrical topology. The circuit comprises of two sections, one is polarity generation circuit comprises of three switches. Second is polarity conversion circuit which is inverter circuit. The switching states of the proposed multi level inverter with specific combination of the switches and corresponding voltage levels for seven-level are shown in the table. The output of the polarity generation circuit is fed to the polarity conversion circuit where positive and negative voltage levels are generated.