Design Implementation of High Boost Embedded Semi Quasi-ZSI for Photovoltaic System Applications

Abstract

The semi Z-source inverter (SZSI) is a well suitable non-isolated converter for grid-connected PV systems, because of its low cost and doubly grounded features. In addition, an SZSI produces a sinusoidal output voltage without using any additional low pass filter circuit. However, the limited output voltage range, the operating region of the duty cycle is restricted to 0.666, discontinuous input currents are the main concerns of SZSI. In order to overcome the above limitations, an embedded semi quasi Z-source inverter (ESqZSI) topology is proposed, that is constructed with two semi quasi ZSIs. Further, a quasi Z-source converter (qZSC) is interfaced as front-end DC-DC converter to implement Perturb and Observe (P and O) MPPT method. The symmetrical and asymmetrical output voltage control methods are presented to improve the voltage profile. The component design specifications and its sizing are clearly discussed for qZSC and ESqZSI. Comparing with H-bridge inverter, the proposed EZSI topology has lower converter ratings, low stress on the system and reduced leakage currents. Finally, the performance of the proposed system is verified through MATLAB/SIMULINK.