Design, Analysis and Development of MPPT Controller for Stand-Alone PV System Using Buck Converter

Abstract

When a PV cell/array is irradiated with solar rays, it converts the solar energy into electrical energy. But, its conversion efficiency is very low. The power and voltage characteristics are non-linear in nature. It shows that there is a point where the PV cell/array reaches its maximum power. This thesis presents a method called the Maximum Power Point Tracking (MPPT) to get the maximum power from the PV cell/array at all times. The power vs voltage and current vs voltage characteristics of the PV panel are experimentally obtained. From the characteristics obtained, we can find out the voltage and current of the PV Panel corresponding to maximum power point i.e. we get VMPP , MPP I and PMPP . The MPPT is performed in simulation by using MATLAB/SIMULINK. The MPPT technique used here is the Perturb and Observe (P&O) method, which is in the form of a recursive algorithm. The graphs of panel voltage ( VPV ), panel current ( PV I ) and load power ( POUT ) are checked. It is verified that the final values of these graphs are very close to the actual values of VMPP , MPP I and PMPP respectively of the panel. The hardware design for the buck converter is done assembling the required components. Open loop operation is performed on the designed buck converter at different switching frequencies. The output voltage and gate-pulse waveforms are observed on the oscilloscope.