Three-Phase Grid Connected ZCT Inverter integrated photovoltaic system

Abstract

When ac loads are fed through invertersit required that the output voltage of desired magnitude and frequency be achieved. Low leakage current and high efficiency are two key two key indexes for transformer less PV grid connected inverter. The transformer less inverter topologies have superior efficiency thanks to saving transformer, but their semiconductor devices are still on hard switching state at present. A variable output voltage can be obtained by varying the input dc voltage and maintaining the gain of the inverter constant. On the other hand, if the dc input voltage is fixed and it is not controllable, a variable output voltage can be obtained by varying the gain of the inverter, which is normally accomplished by pulse-width-modulation (PWM) control within the inverter. First and foremost, a novel zero current-transition (ZCT) conceptsfor the threephase full-bridge transformerless PV gridconnected inverters are presented in this paper. Second, the zero-current turn-off for high frequency main switches of the inverters and the zero current J.Siva Naik M.Hussen Assistant Professor Dept of EEE Collage: NETW Assistant Professor Dept of EEE College: NETW Turn-on for auxiliary switches added are achieved by introducing two resonant tanks. Furthermore, a family of ZCT transformer less grid connected inverter with sinusoidal pulse width modulation is deduced.