Research on Non-isolated Three-level Buck Converter for Photovoltaic Connected to DC Power Supply System

Photovoltaic integrated low voltage DC distribution system (PV-LVDC) has developed rapidly because of its high efficiency, but the high-frequency switching action of DC-DC converter produces common-mode voltage, which leads to excessive leakage current. Aiming at the leakage current problem of three-level Buck DC-DC converter in PV-LVDC, an improved three-level Buck DC-DC converter with leakage current reduction and a combined modulation strategy are proposed, which effectively reduces the leakage current by adding switching transistors to cut off the common mode loop. And a simulation model based on MATLAB/Simulink is built to verify the effectiveness of the improved three-level Buck converter.