A Switched quasi Z-Source Three-Port (SqZSTP) DC-DC converter for photovoltaic power generation system

Abstract

Abstract In this paper, a modified wide input Switched quasi Z-Source Three-Port (SqZSTP) DC-DC converter is proposed to interface the Photovoltaic (PV) inverter with the distributed power generation system. The proposed SqZSTP DC-DC converter constructed with the Quasi Z-Source impedance network and a three-winding High Frequency Transformer (HFT) offers high voltage gain with a wide input voltage range. In the proposed topology the input port has been divided into two ports, to reduce the power rating and voltage stress across each component. The design and operating principle of the SqZSTP DC-DC converter are presented. The steady state and dynamic performance of the proposed SqZSTP DC-DC converter is compared with other converters which has the impedance network in front. The Fuzzy Logic Controller (FLC) used in the voltage loop avoids the variation in the output voltage when the wide variation in the input voltage happens. In order to test the proposed topology, a scaled down model with the voltage and power rating of 400V/1400W was developed. The conversion efficiency of 94.5% is achieved.