Enhancement of Z-Source Inverter Controller for Improvement of Grid-tied PV systems

This paper presents a photovoltaic (PV) system using a three-phase impedance source inverter (ZSI) by optimizing PWM signals to reduce harmonics. One of the advantages of this inverter compared to traditional inverters is to have buck-boost capability. ZSI can increase the output voltage according to its structure. ZSI has the unique feature of shoot-through (ST) operation, which allows short-circuiting the switches of one leg of the inverter, thereby eliminating switching dead time to improve output performance. According to the characteristics of the ZSI, in this paper, by optimizing the PWM signals, the total harmonic distortion (THD) value is reduced and ultimately improves the power quality in the output waveform of the system. The simulation results are obtained using MATLAB/Simulink software.