A highly efficient single-phase transformerless h-bridge inverter for reducing leakage ground current in photovoltaic grid-connected system

摘要

In this article, the performance of the split-capacitor H-bridge topology as a single-phase transformerless photovoltaic inverter is studied. By connecting the midpoint of its two series DC-link capacitors to the ground, the split-capacitor H-bridge is able to clamp the common-mode voltage of the system, effectively suppressing leakage ground current. To overcome the issue of capacitor voltage balancing, a simple balancing circuit and its control are introduced. The operation modes, common-mode voltage, and leakage ground current characteristics of the split-capacitor H-bridge topology are discussed, subsequently validated using both simulation and experimental tests. Comparison with a conventional transformerless H-bridge topology proves the superiority of the split-capacitor H-bridge topology in terms of leakage ground current and efficiency.