High-efficiency PV inverter with SiC technology

摘要

A high-efficiency, three-phase, solar Photo-Voltaic (PV) inverter is presented that has low ground current and is suitable for direct connection to the Low Voltage (LV) grid. The proposed topology includes a three-phase, two-level (2L) Voltage Source Inverter (VSI) and an active Common-Mode (CM) filter. The VSI utilizes Silicon (Si) IGBTs with Silicon Carbide (SiC) diodes to reduce switching losses and provide very high efficiency. The active CM filter reduces the high level of CM voltage associated with the three-phase 2L VSI. The active CM filter is controlled so that the PV ground current is reduced to acceptable levels, even when the PV inverter is connected directly to a LV grid with low-impedance grounding. 50kW and 100kW prototypes are presented that demonstrate high efficiency.