Virtual instrument based maximum power point tracking of a solar panel

Abstract

One of the most important challenges for researchers is to generate energy from fresh, resourceful & environmentally pleasant sources. While greenhouse emissions are reduced, more attention is attracted towards solar system because it offers great chance to produce electricity among all renewable energy sources. In spite of all advantages of solar power systems, they do not show advantageous efficiency. Insolation, Temperature, spectral characteristics of sunlight, shadow, dirt & etc. are the factors, on which efficiency of solar cell depends up on. The output power of photovoltaic (PV) array reduces with the changes in irradiance on panels due to rapid climate changes for example increase in temperature and cloudy weather. It can also be said as, according to operational and environmental conditions, each PV cell produces an energy. From the poor efficiency point of view some procedures are given, from which a concept called as “Maximum Power Point Tracking” (MPPT). The goal of all MPPT methods are identical to improving the output power of PV array in every condition by tracking the maximum power. Solar cells have non-linear i-v characteristics. By the series connection of PV cell, output voltage of PV panel increases. Similarly, by the parallel connection of PV cell output current of PV array increases. Many MPPT algorithms are there to track maximum power point such as perturb and observe (P&O), incremental conductance, constant voltage, constant current and parasitic capacitance algorithm etc. Perturb and observe algorithm is a simple algorithm but it tracks wrong direction with the sudden change in weather and it oscillates about the MPP (Maximum power point), which can be eliminated by using incremental conductance algorithm. Under partial shadow condition, P-V (power-voltage) characteristic curve is having multiple peaks. At that time, it is difficult task to track actual maximum power point.