S4 grid-connected single-phase transformerless inverter for PV application

© 2016 IEEE. A novel transformerless inverter for grid-tied PV systems is introduces with low leakage current in this paper. Four power switches, two capacitors, two diodes, and a LC filter are uses in this topology. The negative polarity of the PV panel is connected to the neutral of the utility grid with common line. Therefore, a common-mode voltage is constant and leakage current is nearly zero. A unipolar Sinusoidal Pulse-Width modulation (SPWM) method is utilized to reduce the output current ripple and requirements of filter. The major merits of this topology are compact size, low cost, flexible grounding configuration and higher efficiency. The operating principle and analysis of the proposed inverter are presented in details. Finally, a universal prototype rated 500 W are tested to validate the proposed topology and the overall concept. The results obtained clearly confirm the performance and practical application of the proposed topology for grid-connected PV systems