A high gain observer design for the three-phase shunt active power filter interfacing a photovoltaic source

Abstract

In this article, a nonlinear observer is designed for a system consisting of a PVS photovoltaic source associated with a shunt active power filter (SAPF) and connected to a three-phase electrical network. In addition to improving the quality of energy in the distribution network (unity power factor), the use of SAPF also allows the injection of photovoltaic energy into the network. Since the system model is nonlinear and some variables are unknown (inaccessible to measurement), a high-gain observer is constructed. The advantage of this solution lies in the estimation of the unmeasured state variables (variables of the photovoltaic source). It is shown using theoretical analysis, under certain conditions of persistent excitation, that all estimation errors disappear exponentially. The effectiveness of the solution is verified by numerical simulation under Matlab/Simulink.