A five level dual buck full bridge inverter with neutral point clamp for grid connected PV application

Abstract

A neutral point clamped five-level dual buck full bridge grid-connected inverter, derived from a three-level dual buck full bridge inverter (TLDBFBI) combining two input split-voltage capacitors and two clamping branches, is proposed. The voltage step on both the filter inductors and the switching devices in the new topology is only half of the input voltage, which offers a smaller size of the inductors. Only one of the switches is operated at high switching frequency at any time, which offers lower switching losses. Moreover, the operation principle and modulation of the proposed topology are analyzed in detail, and a prototype is built. Experimental results show that compared with TLDBFBI, the efficiency and power density are improved by the proposed neutral point clamped five-level dual buck full bridge inverter (FLDBFBI).