풍력발전시스템에서 풍속 추정을 이용한 최대 출력 제어

Abstract

Variable-speed wind power system is controlled by optimal tip speed ratio between angular speed of the blade and wind speed to track maximum power point. Conventional method of using anemometer to measure wind speed is expensive. Moreover, the measured wind speed and the wind speed that is applied to turbine blades are different depending on the position of anemometer. For these reasons, control methods using wind speed estimation based on Kalman filter and Newton-Raphson method are employed to estimate the wind speed. But the parameters that are used for wind speed estimation are changed due to degradation of generator and blade shape. Also, the air density is changed continuously. This causes not only inexact maximum power point tracking but also inaccurate wind speed estimation. In this paper, to solve this problem, an maximum power control algorithm is proposed to wind power system based on wind speed estimation. A correction factor is introduced to consider the changes in blade shape, air density and generator efficiency. The correction factor reduces the error in estimated tip speed ratio thereby estimating the wind speed with better accuracy. Also, maximum power point is tracked. For the simulation, wind power system based on wind speed estimation with the proposed algorithm considering converter control is designed using Matlab/Simulink and the performance of wind power system is validated with constant and variable wind speed. The results show that the adaptive MPPT control has better estimation of wind speed from the correction factor that is computed