Comparative Analysis of Three Phase Hybrid Transformerless Inverters for PV applications

Recently, transformerless grid connected inverters are developed for PV system to increase the overall efficiency of the system and to reduce the system cost. The main draw back of the transformerless inverter topology is isolation during grid fault, leakage current (LC) elimination, common mode voltage (CMV) and reactive power compensation. DC and AC decoupled transformerless inverter topologies have been developed to eliminate the drawbacks, these topologies have high switching losses. To eliminate the high switching loss and to improve the reactive power compensation, hybrid transformerless inverter topologies with modified discontinuous pulse width modulation (MDPWM) is proposed in this paper. Mathematical analysis of switching loss and reactive power compensation is carried out. Simulation results are discussed for LC elimination and CMV using MATLAB/Simulink.