Research On Single-Phase Hybrid Three-Level Inverter

A novel single phase Three-Level inverter is proposed ,which is named Hybrid Three Level inverter. A leg of Neutral-Point Clamped inverter takes place of one of the two legs of the conventional full-bridge inverter. The great advantage is the harmonics of the output voltage is reduced a lot, so the size of the output filter can be reduced greatly. It is detailed to analyze two kinds of control strategy, -SPWM and HCPM(Hysteresis Controlled Pulse Modulation).In this paper, a kind of output current feed-forward circuit is added into the input of the current loop. By adding this compensatory circuit, the output character of the inverter is improved greatly.A 2kVA prototype is built to verify the validity of the proposed inverter.