A novel switched-capacitor based single-phase five-level transformerless inverter

Abstract

This paper proposes a 5-level single-phase transformerless inverter topology for grid-connected PV applications. The new topology makes use of a switched-capacitor network on the input side and eliminates leakage current completely by maintaining the Total Common Mode Voltage (TCMV) constant. The proposed inverter topology has the advantage of complete multi-level performance resulting in low harmonic distortion in the output voltage and reduction in device stress. Moreover, the proposed inverter topology eliminates the need for isolation as the TCMV is constant, resulting in mitigation of leakage current. TCMV analysis of the proposed topology is carried out including the effect of switch parasitic capacitance to show its capability of complete elimination of leakage current. Furthermore, the proposed topology is capable of feeding reactive power into the grid. Simulation results of the proposed topology with grid connection are presented to illustrate the various capabilities.