DCM-232 converter: A PV transformerless three-phase inverter

Nowadays transformerless PV converters are widely used in the energy conversion stage of a PV plant, because their good characteristics regarding efficiency, size, cost and weight. The main problem in transformerless PV systems is the common mode voltage variations that can generate leakage ground currents (LGC) through the parasitic capacitance formed between the PV panels and ground. These LGC are a risk for the users in a PV system therefore they should be avoided. The LGC has a clear origin on the pulse width modulation (PWM) strategy and the converter structure. In this paper a three-phase inverter with constant common mode voltage (CMV) is proposed. Simulation results are also provided.