Transformerless grid connected single phase inverter for power system application

Transformerless single phase photovoltaic inverter has attracted power generation system due to its higher efficiency and low cost. One of the main problems in transformerless single phase photovoltaic inverter is to control leakage current appearing between parasitic capacitor and ground. The leakage current has to be controlled to avoid EMI problem and circuit damage. The main goal of the proposed work is to control the leakage current by keeping the common mode voltage constant. This is achieved by applying unipolar SPWM strategy - Basic SPWM strategy and Bidirectional SPWM strategy. This increases reliability of the circuit. Total Harmonic Distortion [THD] is reduced by keeping common mode voltage constant. The inductance size in circuit is decreased by reducing the leakage current. PV cells have been used for simulation. For hardware a battery representing PV cell has been incorporated for studies.