Modulation Strategy for Minimisation of Leakage Current in Grid-Connected PV Panels 2019-28-0114
This paper presents a switching strategy for the cascaded multilevel H bridge inverter of five levels to reduce the leakage current in the grid connected transformerless PV system. Minimization of the leakage current in solar panels is vital in a transformerless grid connected PV panels. But due to the absence of transformers which provide galvanic isolation, CMV techniques are applied which results in leakage currents from PV panel to ground. This current causes hazards to humans and large currents may lead to fire hazards. The proposed switching strategy reduces the continuous transients at switches, hence avoiding high frequency switching. This switching technique requires only a single modified carrier wave for all 2m+1 levels of operation. The sinusoidal carrier waveform is modified as humped sinusoidal waveform to reduce switching losses. In this paper, the progressed switching strategy has been incorporated to PV fed five level multilevel inverter connected to grid and its effectiveness has been validated.