New control strategy for DCM-232 three-phase PV inverter with constant common mode voltage and anti-islanding capability

Eliminating the leakage current with new converter topologies and modulation strategies is one of the most important issues for transformerless PV systems. A new carrier-based modulation strategy for DCM-232 three-phase PV topology is proposed in this paper. Thanks to the presented method, the common mode voltage of DCM-232 converter can be kept constant, and the leakage current is greatly reduced without requiring complex space vector modulation. In addition, a simple control strategy is presented for the accurate grid current regulation, as well as anti-islanding capability. Performance test results verify the effectiveness of the proposed method.