43 Page 33-42 © MAT Journals 2019. All Rights Reserved Journal of Electrical and Power System Engineering Volume 5 Issue 2 Avoidance of Drift due to change in Irradiation in Photovoltaic System with Modified Perturb and Observe MPPT Algorithm Amit Bhuyar 1 , Ujwala V Dongare 2 1 PG Student, 2 Assistant Professor, Department of Electrical Engineering, Government College of Engineering, Amravati, Maharashtra, India Email: *amitbhuyar.25@gmail.com Abstract Efficiency of PV system is depending on maximum power point tracking (MPPT). It will help to extract maximum power from PV system. Perturb and Observe (P&O) maximum power point tracking algorithm is adopted everywhere, due to its simplicity and economic point of view. But in case of rapid change in insolation (G), it suffers from drift in tracking maximum power point (MPP). It is the main demerit of the P&O MPPT algorithm. This may happen due to confusion of whether power get increases due to perturbation or change in insolation(G). The drift effect is severe in case of a rapid increases in irradiations. This technique proposed in this study leads to avoid drift in tracking maximum power point (MPP). SEPIC converter are proposed with direct duty ratio control technique for free from drift in P&O MPPT algorithm. MATLAB/Simulation modeling and analysis of a voltage and power of PV system under rapid change in atmospheric condition with conventional P&O algorithm. Study to drift phenomenon. The comparison between conventional P&O and Modified P&O is shown in simulation and experimental results, which are showing changes in duty cycle, that the proposed algorithm track maximum power in change in insolation (G). Keywords: Drift phenomena, maximum power point tracking (MPPT), photovoltaic (PV), perturb and observe (P&O) INTRODUCTION Due to increase in level of greenhouse emission gas and climb in fuel prices are the main reason behind efforts to utilize various uses of renewable sources of energy. Among them electrical energy from photovoltaic (PV) cells is widely used as a natural energy source that is more useful, since it is free, abundant, clean, and distributed over the earth. The main difficulty of solar energy is the initial high capital cost of PV modules. The disadvantage of solar energy production is that the power generation is not constant throughout the day, it changes with weather conditions. The efficiency of solar energy conversion to electrical energy is very low. This means that a fairly vast amount of surface area is required to produce high power. Therefore, maximum power point tracking (MPPT) is an essential part of the photovoltaic (PV) system to ensure that the power converters operate at the maximum power point (MPP) of the solar array. There are so many MPPT techniques that have been developed to increase the efficiency of the PV system. MPPT algorithms such as, fractional short circuit current [3], Hill-climbing [4], incremental conductance (Inc. Cond) [3], incremental resistance (INR) [4], ripple correlation control (RCC) [4], perturb and observe (P&O) [3]– [4] fuzzy logic [9], neural network [10], particle swarm optimization (PSO) [11] techniques are some of the MPPT techniques. Overview of various MPPT techniques are discussed in [13]. While generating electric energy from Photovoltaic system(PV) are: the efficiency of electric power generation is very low,