Perturb and observe based maximum power point tracking of wind power system

Abstract

Maximum power obtainable from a wind generator depends on the wind speeds. So, for varying wind speed conditions, tracking the maximum power point is essential for efficient power transfer to the grid. There are several gradient based search methods which are employed in maximum power point tracking (MPPT) of the wind generator. There are steepest descent method, hill climbing method, etc. The Perturb and Observe (P&O) method is one of the simple gradient techniques, which have been used in this work. The perturb and observe (P&O) method identifies the maximum power point (MPP) by adjusting the rotor speed of a wind turbine. The algorithm works by perturbing the rotor speed of the wind turbine and observing the change of power output for a certain wind speed. If the power output increases, the algorithm will continue to perturb the rotor speed in the same direction until the power output decreases. At this point, the algorithm changes direction and starts to perturb the rotor speed in the opposite direction. This process is repeated continuously, and the rotor speed is adjusted as necessary to track the maximum power point. Also, the corresponding rotor and power errors are measured by calculating differences between their estimate and actual values. The proposed algorithm entire process has been simulated by using MATLAB and tested under varying wind speed conditions. The simulation results show that the rotor speed followed the change in wind speed properly, indicating the effectiveness of the algorithm in tracking maximum power output. Also, the rotor speed and corresponding power errors have been measured, which is to very negligible errors. So, this algorithm is utilized to obtain the maximum power point (MPP) with easy computational effort.