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

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

Keywords:

DC-DC Buck converter; PV Emulator; Maximum Power Point (MPP),

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