Analysis and implementation of a single-phase multilevel inverter for power quality improvement

A single-phase multilevel inverter with.-the function of power factor corrector and active power filter is proposed to reduce harmonic currents flowing into the power system and to draw a nearly sinusoidal line current with unity power factor. The circuit topology of the proposed inverter is based on a conventional full-bridge inverter with one AC power switch. The switching signals of the power switches are derived from the voltage balance compensator, current controller and detected operation region of mains voltage. A three-level PWM voltage pattern on the AC side of the inverter in each half cycle of mains frequency is performed. Simulation results are implemented to verify the validity and effectiveness of the proposed inverter with the function of power factor corrector and active power filter.