Leakage current suppression for PV cascaded multilevel inverter using GaN devices

This paper emphasizes on the leakage current suppression of a PV cascaded multilevel quasi-Z-source inverters (qZSIs) using GaN devices. This new type of PV inverters is capable of achieving high efficiency and high switching frequency. However, the leakage current issue remains a challenging that needs to be dealt with. In this paper, the leakage current paths in PV cascaded inverter are firstly analyzed. Based on that, a filter-based leakage current suppression method is proposed for the PV cascaded inverter operated at high switching frequency. The simplified leakage current analytical model is derived to study the suppression mechanism and design the suppression filters. The performance of the method is validated with both simulation and experimental results.