Seven‐level dual‐buck inverter for photovoltaic power generation

Abstract

A power processing system (PPS) with a seven‐level dual‐buck inverter (SLDBI) for a photovoltaic (PV) power generation system is proposed. The PPS is comprised of a boost power converter and an SLDBI. The boost power converter matches the voltage of the PV array with that of the SLDBI and functions as the maximum power point tracker for the PV array. The SLDBI consists of a dual‐buck bridge converter (DBBC) and a three‐level DC converter (TLDC). The DBBC effectively reduces leakage current in the PPS and prevents current from flowing through the parallel body diode of the power switches, allowing the use of MOSFETs as power electronic switches to enhance power efficiency. The TLDC is structured as a semi‐controlled full‐bridge system to generate a three‐level DC voltage. Besides, the DBBC and TLDC produce a seven‐level AC voltage and drive a sinusoidal current to the utility. The SLDBI reduces both the filter inductor size and the switching loss of power switches. With only six power switches, it simplifies the power circuit. A hardware prototype has been built to experimentally verify the proposed PPS.