High Efficiency Single Phase Transformerless Inverter For Grid Connected Pv System

Abstract

 The grid tied photovoltaic system suffers a great loss because the performance of the transformer present in the inverter. The cost of the transformer is high and the maintaince cost is also high. Therefore transformer less inverter are widely used in grid tied photovoltaic system, due to the benefits of achieving high efficiency and low cost. The sinusoidal pulse width modulation of full bridge transformer less inverters can achieve high efficiency by using metal oxide semiconductor field effect transistor. Various topology has been implemented for transformer less inverter, but in that there is a problem of loss and reverse recovery characteristics. In our paper we are going to implement the centre tapped H bridge transformer less inverter topology for grid tied photovoltaic system to avoid the losses and leakage current. A clamped branch is added in the transformer less inverter. The added clamping branch clamps the freewheeling voltage at the freewheeling period. As the common mode voltage is kept constant for the whole grid period that reduces the leakage current. The splitting structure of inductor at the region of grid side avoids reverse recovery voltage and this improves the efficiency of the system. The detailed analysis of our topology with the operational modes, leakage current analysis and design consideration were implemented.