Emulation of a photovoltaic module using a wiener-type nonlinear impedance controller for tracking of the operation point

Abstract

This paper proposes a control method to provide the function of Solar Panel Emulation (SPE) to a low-cost programmable DC source. The proposed control operates with base on the error between measurement of the conductance connected at the output of the SPE and the conductance obtained evaluating the I-V characteristic of the panel model. The principle of operation is that the output of the controller modifies the value of the voltage introduced into the W-Lambert function to obtain the corresponding current enforcing the regulation of the measured conductance. In this paper, a controller composed by a nonlinear static gain and a conventional PI controller is proposed. The controller architecture configures a Wiener system structure which ensures the stable convergence of the real SPE variables to the values defined by the model. Simulation results are presented evaluating the dynamic performance of the system for irradiance and load variations. SPE method is implemented using simple measurement and conditioning circuits interacting with an application developed in LabVIEW through a data acquisition card. This implementation provides a complete solution highly applicable in research and industrial development.