Performance Improvement of Photovoltaic Emulator Using Lambert W Model and Fractional Order PI Controller

A photovoltaic (PV) emulator replicates the exact I-V and P-V output characteristics of a PV module or array. This replication should have occurred in such a way the same output characteristics in different ambient conditions, including different temperature and irradiation levels, mismatching, or partial shading, have been obtained. In this paper, a PV emulator based on a DC-DC converter with a novel control method has been presented. The proposed controller is a fractional PI one optimized with Grasshopper Optimization Algorithm (GOA). It has one degree of freedom more than the conventional PI controller, which is the main advantage of this control approach. Also, a fractional-order lag compensator is used to decrease the output ripple of the converter. On the other hand, the Lambert W function models the PV characteristics which this modeling approach reduces computational burden and time. The simulation results in MATLAB/Simulink validate the performance of the proposed PV emulator.