Design and Implementation of Photovoltaic Inverter Techniques in DC Current Suppression and Maximum Power Point Tracking for Grid Connected System

Abstract

In this proposed model, the design of grid connected transformer-less inverter for Photo-Voltaic (PV) system is implemented with the concept of DC current elimination which aims at higher efficiency, lower weight and free from offset measurement errors. In recent years of transformer less Photo-Voltaic (PV) inverters, the non-galvanic isolation configuration leads to common mode voltage which results in leakage of current to the ground through the Photo-Voltaic stray capacitance. Another main concern of existing model comes in inverter output stage when injection of DC current is done inside the AC grid line because of the disparity of power switching circuits and asymmetry of driving pulses. This new control technique of inverters with DC current elimination using a suppression loop that consists of a difference amplifier and a filter is proposed to make the system highly reliable. Since this technique excludes the DC component, the even harmonics in the current passing through the grid is considerably reduced. The whole design of proposed model has been verified using MATLAB software according to the theoretical analysis of the system.