Three-phase DC-bypass topologies with reduced leakage current for transformerless PV systems

Leakage current reduction is one of the most important issues for transformerless PV grid-connected inverters. Many interesting single-phase topologies have been reported to reduce the leakage currents. However, three-phase PV inverter topologies with reduced leakage currents are not received much attention. In this paper, a new family of three-phase topology is proposed to reduce the leakage current for transformerless PV systems. It derives from the single-phase dc-bypass topologies, and a new modulation is presented to coordinate the dc-bypass switches and H-bridge switches. Theoretical analysis and performance tests are carried out to verify the effectiveness of the proposed topology.