Common-mode EMI suppression based on chaotic SPWM for a single-phase transformerless photovoltaic inverter

Abstract

The transformerless photovoltaic (TPV) inverters can cause serious common-mode electromagnetic interference (EMI) due to the parasitic capacitors between the solar arrays and ground. In this paper, chaotic SPWM is firstly proposed to suppress the common-mode EMI in TPV inverters. The EMI suppression mechanism of chaotic SPWM is introduced, and chaotic SPWM is further applied into a single-phase TPV inverter, the equivalent common-mode current loop of the single-phase TPV inverter is established, moreover, the common mode currents of the TPV inverter under SPWM and chaotic SPWM are given and their spectra are analyzed. Finally, the simulation and experiment results validate the effectiveness of chaotic SPWM in common-mode EMI suppression.