A novel AC photovoltaic module system based on the impedance-admittance conversion theory

A novel photovoltaic (PV) power generation system based on impedance-admittance conversion theory is described in this paper. AC photovoltaic module systems (AC modules) have attracted interest for their application in PV power generation systems. An AC module has an integrated inverter that allows the module to supply AC power to the utility power line. One distinctive feature of system proposed in this paper is that the output current supplied to the utility line has a similar waveform to the utility voltage, and is proportional only to the output voltage of the voltage source inverter on the AC module. This effect is achieved through use of the impedance-admittance conversion theory, by which the voltage source is converted to the current source, and vice versa. Therefore, in the proposed system, the output current supplied to the utility line can be controlled without being affected by the utility line voltage. Hence, it is not necessary to use current feedback control. The effectiveness of the proposed system is confirmed through simulations and experiments.