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 emulating the dynamic characteristics of PV sources in real time are gaining importance. This paper presents a new algorithm for emulation of PV characteristics using a DC-DC buck converter in current control mode. The algorithm tracks the point on the V-I characteristics of the PV under varying loads by generating the corresponding current reference. This reference current is used for the generation of gate pulses for the DC-DC converter, which acts like a constant current source to emulate the PV panel. In the proposed system, real time variation of irradiance and temperature are incorporated as a time varying input parameters to the PV emulator. The proposed algorithm has been simulated numerically using MATLAB/SIMULINK platform and is experimentally verified on a laboratory test bench consisting of a DC-DC buck converter of 50 W rating with AT'mega328 as a core controller. Both simulation and hardware results are presented showing the effectiveness of the proposed system under dynamic loading and environmental conditions.