Performance Enhancement of Grid Integrated Photovoltaic System Using Luo Converter

Abstract

The main aim of this article is to implement a novel active power decoupling-based Luo converter for the weak grid system interfacing photovoltaic (PV) system. The modified Perturb and Observe (P&O) algorithm has been used for maximum power extraction from the PV source. The proposed system is capable of operating in the standalone mode and the grid-connected mode. The Luo converter is promising with the viewpoint of low inrush current, high voltage gain, small ripples along with high power density, high efficiency, and simple structure. Hence, the Luo converter has been used for maximum power extraction from the PV source, which is appropriate for both grid-tied and islanding modes of operation. The modified P&O algorithm has been used for maximum power extraction. The proposed MPPT technique reduces the drift problem, which occurs in the conventional MPPT methods by including the data of change in current ( $\Delta I$ ) in addition to the data used in the conventional P&O algorithm. This extraction has achieved by using a novel decoupling method, which, in turn, reduces the size of the filter. The converter along with the decoupling method also ensures reduced harmonics at the grid output. The operational principle and the stability analysis of the proposed converter have been analyzed in different modes of operation, such as grid-connected mode and standalone. The simulation has been carried out in MATLAB/Simulink environment. The implementation of the converter is carried out using a microcontroller-based prototype model to validate the performance. The efficiency of the proposed converter has been calculated to be 87.53% when operating under the grid-connected mode, whereas the efficiency is 92.46% when operating under the standalone mode.