Abstract: The usual grid-connected renewable energy source inverters have either a line frequency or a high frequency transformer between the source and the grid. This transformer is mainly focused for galvanic isolation between the load and the source. By removing the isolation transformer, we can achieve the effective solution and also reduced size and cost. This elimination produces the common mode ground leakage current, because of parasitic capacitance between the PV panel and ground. The common mode (CM) leakage current will reduce the efficiency of power conversion, and also affects grid current, deteriorate the electric magnetic compatibility and rise the safety threats. To eliminate the common mode (CM) leakage current, the virtual DC bus concept is implemented in this paper. When we connect grid neutral line to DC bus negative pole, the stray capacitance exists between the PV panel and ground is bypassed. The Common mode (CM) ground leakage current would be completely eliminated. To provide negative voltage level for negative AC grid current generation, the virtual DC bus is created. The virtual DC bus is implemented with the switched capacitor topology that uses less number of elements. Hence, the power electronic cost would be reduced. This topology can be implemented with the unipolar SPWM to reduce the output ripple. A small inductor, which can be used as filter will reduce size and magnetic losses. The simulation result of the proposed topology using MATLAB/SIMULINK is presented.
Keywords: Virtual DC Bus; PV cell; SPWM; Transformer less.
Title: Virtual Implementation of Transformer less Inverter for Grid Connected Photovoltaic Cell
Author: K. Priyanka
International Journal of Electrical and Electronics Research
ISSN 2348-6988 (online)
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