Dead-time Effect on the Leakage Current of Grid Connected Single-Phase Photovoltaic Inverter

The transformerless photovoltaic (PV) inverters are preferred in the PV systems because of its higher efficiency and lower cost. Due to the lack of galvanic isolation between the grid and PV panel, the leakage current flows through the parasitic capacitance of PV panel and the grounded neutral point of the power transformer. Since the high-frequency components on the common-mode (CM) voltage is the main source for this current, the switching logic of devices in the PV inverter is usually arranged to suppress the leakage current circulation below the limit of safety standards. The dead-time is also a parameter of CM voltage waveform. The smaller dead-time of the wide-bandgap device GaN HEMT is considered as the advantage on the leakage current mitigation. It is experimentally investigated on the single-phase active clamped snubber-based inverter (ACSBI) topology here. The results with IGBT and GaN HEMT devices used in the ACSBI are compared in this paper.