Common-Mode Leakage Current Eliminated Photovoltaic Grid-Connected Power System for Domestic Distribution

Abstract

Improved single-phase inverter topology is used to avoid the common-mode leak age current in the transformerless PV grid-connected system. The condition of elim inating common-mode leakage current in both the unipolar sinusoidal pulse width modulation (SPWM) and the double frequency SPWM control method can be ap plied to implement AC output in the presented inverter. By decoupling of two addi tional switches connected to the dc side the efficiency and convenient thermal design are improved. Besides, the higher frequency and lower current ripples are obtained by adopting the double-frequency SPWM, and thus the total harmonic distortion of the grid-connected current are reduced to 7 percentage. It is used for low ac power application. Working of the proposed circuit and verification by simulation results are discussed in this paper. Simulation is done in MATLAB R2010a version