A modelling case study of an island mode solar power plant

Abstract

This paper deals with efficiency analysis of a solar power plant that is considered to be installed in island mode with 2 kWp rated power. The test bed designed in Simulink © consists of solar panel, buck converter, and H-bridge inverter models all based to analytical concepts. The solar panel model is designed according to equation of a solar cell, and all the required parameters such as open circuit voltage, short circuit current etc are considered in order to modify the output power regarding to a commercial photovoltaic (PV) panel. The dc-dc conversion is performed with a buck converter where the optimal duty cycle is dynamically updated by a proportional-integral (PI) controlled generator. The settling time and dc voltage ripples are minimized to increase the efficiency of the dc-dc converter. On the other hand, the single-phase inverter is constructed with an H-bridge that is the most basic multilevel topology known ever. The main intention during the inverter operation was decreasing the total harmonic distortion (THD) ratios as much as possible. Therefore, the modulation scheme is particularly applied to decrease THD by eliminating side band harmonics. The line voltage is properly fixed to 220V/50Hz that is common in northern and central Europe. The THD ratio of the line voltage is measured at 0.03%, while the THD of the current is 0.82%. The power factor of the entire system is measured as 0.99 considering the 8.1° phase displacement between current and voltage waveforms. The analysis results verify the efficiency of the proposed solar power plant and its components.