An Integrated Step Up Inverter Without Transformer and Leakage Current for Grid Connected Photovoltaic System
In this paper, an integrated step up inverter without transformer is investigated for photovoltaic (PV) power generation. The proposed topology can be derived by combining a traditional boost converter with a single phase full bridge dc ac converter. The main features of the integrated inverter are: First, the leakage current caused by the solar cell array to ground parasitic capacitance can be theoretically reduced to zero due to the characteristics of the converter configuration, which can improve the efficiency and the reliability of the PV generation system; second, the output ac voltage of the proposed inverter can be higher than the input dc voltage, which is capable of connecting low voltage PV panels to the grid; third, only five active switches are used in the presented inverter, and those switching devices can be synchronously driven by various sinusoidal pulsewidth modulation methods based on the carrier; therefore, the proposed inverter is compact and with curtailed cost. The working principle and analysis of the proposed integrated inverter are elaborated. Finally, simulation and experimental results are obtained in a lab prototype, which agree well with the theoretical analysis.
IEEE Transactions on Power Electronics