Experimental Verification of Grid-Connection of a PV Converter Using a Symmetrically Connected Boost Converter for a High-Leg Delta Transformer

This paper proposes a grid-connection control method of the previously-proposed PV converter using a symmetrically-connected boost converter. The proposed circuit has an advantage in its switching operation since the symmetrically connected boost converter and the inverter can alternately stop switching, reducing the switching power losses. In the proposed grid-connection control method, the boost converter performs feedback control of the dc link voltage to make the grid current sinusoidal during the switching interval in the inverter. This paper theoretically clarifies the operating principle of the proposed grid-connection control method and confirms its operating performance using a 8-kW experimental system. As a result, the proposed grid-connection control method makes it possible to control the grid current as a sinusoidal waveform.