Performance Analysis Through Modeling & Simulation of Different Power Converters using MATLAB/Simulink

Abstract

The recent upsurge in the demand of PV systems is due to the fact that they produce electric power without hampering the environment by directly converting the solar radiation into electric power. However, the solar radiation never remains constant. It keeps on varying throughout the day. The need of the hour is to deliver a constant voltage to the grid irrespective of the variation in temperatures and solar insolation. We have designed a circuit such that it delivers constant and stepped up dc voltage to the load. We have studied the closed loop characteristics of the PV array with variation in temperature and irradiation levels. Then we coupled the PV array with the boost converter in such a way that with variation in load, the varying input current and voltage to the converter follows the open circuit characteristic of the PV array closely. At various insolation levels, the load is varied and the corresponding variation in the input voltage and current to the boost converter is noted. It is noted that the changing input voltage and current follows the open circuit characteristics of the PV array closely. Initially three basic converters namely Buck, Boost and Buck-Boost were studied. Proper voltage regulation is obtained with the use of PID controller along with the converter. The proposed converters offered better efficiency, reduced overshoot. Converters offers best performances in simulation have been implemented in laboratory experiment. The input power of the converter is taken from the Photovoltaic cell which contains high distortion and harmonics. Moreover, it is a weak signal. For this step up, step down converters are used and with the integration of PID, better quality power supply can be ensured.