An Improved Unipolar SPWM for Transformerless PV Grid Connected Inverter

摘要

The transformerless operation of grid interactive photovoltaic (PV) systems decreases the cost, size, weight and enhances the systems total efficiency. However, if the transformer is eliminated from the PV system, no galvanic connection exists between the local grid and PV system. In this condition, a leakage current flows through the PV parasitic capacitor and the local utility grid. In order to eliminate this leakage current, various transformerless inverter topologies have been proposed. In this paper a modified unipolar sinusoidal pulse width modulation is implemented for H6 DC decoupled grid connected inverter in order to curtail the flow of leakage current and enhance efficiency. The proposed PWM is simulated in MATLAB to certify the theoretical investigation.