Complete Small-Signal Model of Three-Phase Photovoltaic Inverter Considering the Source and Load Effects

Abstract

The amount of photovoltaic inverters connected to the electrical grid is increasing. In order to control the power fed to the grid, the inverter must be controlled, and many different approaches for small-signal modeling have been proposed to facilitate the controller design. However, a solar panel cannot be modeled by an ideal current source and the photovoltaic inverter is not connected to an ideal grid on the load side. This paper proposes a generalized method to include the load and source effects to the dynamic model of a photovoltaic inverter. The method can be used to include the source impedance of the photovoltaic generator and impedance of the distribution line in the small-signal model of the photovoltaic inverter.