Transformerless Single Stage High Boost PV Inverter with Reduced Leakage Current

Grid connected PhotoVoltaic (PV) inverters are gaining importance with latest development in power electronic devices. In such PV systems, the PV arrays are directly connected to the grid without any isolation. This reduces the size of the system as transformer occupies much of the space and the cost and control is also reduced significantly. The single stage PV inverters traditionally have PV arrays connected together to produce high DC voltages greater than line value of the grid voltage. Recently medium level power electronic PV inverter topologies are introduced to eliminate the step up transformer. During partial shading on PV arrays the Global Maximum Power Point (GMPP) occurs at low voltages. In those conditions the medium level inverters lags behind in boosting the low PV voltage to grid voltage level. In this paper, a high boost PV inverter is proposed for converting low PV DC voltage to grid voltage. The proposed PV inverter have six power electronic switches and doesn't employ any energy storage devices for continuous grid injection at any voltage levels of Maximum Power Point (MPP). The proposed Pulse Width Modulation (PWM) strategy also reduces the leakage current caused by the parasitic capacitor occurring between the PV module and the ground.