Modelling of Grid Integrated PV System using Modified MPPT Technique

World-wide demand for renewable sources is increasing drastically. One of the vital renewable energy sources is the solar energy. This energy is plentily available in nature and also free of cost. To obtain electrical energy from solar energy solar photovoltaic cells are used. But its efficiency is very low due to its nonlinear characteristics. Hence, it is necessary to obtain maximum available power from these solar cells by using a tracking algorithm known as, maximum power point tracking (MPPT). There are various tracking mechanisms available for extraction of maximum power. Perturb and observe is one of them. It is difficult to track the MPP under continuous variation in atmospheric conditions. The causes are partial shading by clouds or tall obstacles and rapid alteration in solar irradiation. It is also necessary to keep track of maximum power point under variation of the load conditions. This article explains about the issues related to conventional perturb and observe algorithm under varying irradiance and its characteristics under load changing conditions. The improved MPPT algorithm is realized in the DC-DC converter control circuit. This study and observation were done with help of MATLAB simulation software. The output of modified MPPT algorithm is equated with the conventional algorithm.