Development of a Microcontroller Based PV Emulator With Current Controlled DC/DC Buck Converter

Abstract

Testing and validation of Photovoltaic based energy conversion systems requires Photovoltaic (PV) panels in laboratory environment. A flexible testing system, which eliminates these panels and emulates dynamic characteristics of PV sources in real time are gaining importance. This paper presents a new algorithm for emulation of PV characteristics and is implemented using DC-DC buck converter in current control mode. The algorithm tracks the point on the V-I characteristics of the PV under varying loads and corresponding current reference is generated. This reference current is used to generate gate pulses for the DC-DC converter, which acts like a constant current source to emulate the PV panel. The P-V and V-I characteristics under desired environmental condition is emulated using load resistance based algorithm for a given specifications of the PV source. In the proposed system, online variation of irradiance and temperature are incorporated as a time varying input parameters to PV emulator. The proposed algorithm has been numerically simulated using MATLAB/SIMULINK platform and is experimentally verified by means of a DC-DC buck converter (50W) prototype with AT’mega328 core controller prototype. Both simulation and hardware results are presented showing the effectiveness of the proposed system under dynamically varying loading and environmental conditions