High‐frequency common‐mode voltage mitigation for current‐source inverter in transformerless photovoltaic system using active zero‐state space vector modulation

Abstract

Space vector modulation (SVM) schemes with leakage current mitigation capability for current-source inverters (CSIs) in transformerless photovoltaic (PV) systems have not been well explored yet. In this study, the advantage of a special SVM scheme, called active zero-state SVM (AZS-SVM), on suppressing high-order harmonics in the common-mode voltage (CMV) is revealed and theoretically analysed, since the high-frequency components in the CMV have decisive impacts on the generated leakage current. A five-segment sequence is proposed for AZS-SVM applied for CSIs. Both simulation and experiments are conducted on a (2.5 kW/208 V/6.94 A) grid-connected three-phase CSI, which validates the effectiveness of the designed AZS-SVM to mitigate the CMV high-order harmonics when compared to that by conventional SVM under different operating conditions.