A New Three-Phase High Performance H8 Filter Clamped Transformer-less Inverter for Grid-tied Photovoltaic Systems

Renewables such as solar, wind, tide energies are the new route for alternative power sources in spite of fossil fuels or other nonrenewable energies. From the last decade, converting the variable solar dc power to constant ac power has become a challenge. This paper underpins a novel three phase transformer-less grid connected photovoltaic inverter with the control blocks applicable for all types of grid voltage ranges. This novel three-phase inverter topology not only contains very lower reduced leakage current as well as less total harmonic distortion (THD) but also improved power quality. Filter clamping approach has been owned to eliminate extra leakage current through the ground path. Besides unipolar sinusoidal pulse width modulation (SPWM) method has been used to control the power switches. As a result, the common mode voltage has been held to constant, which is also responsible for reducing leakage current to 25.42 mA. The leakage current suppression has been analyzed in details with simulation results. The switches did not affect the efficiency of this inverter so much but reduced the leakage current. Switching losses and conduction losses are very low. The THD of Grid voltage of this proposed topology is recorded 0.94% likewise, grid current THD is measured as 0.42%. To check the performance of this proposed inverter more accurately, input voltage as well as load amount of this inverter have been changed instantly in the middle of simulation. This topology has been implemented and tested via MATLAB/Simulink platform.