An Improved Decreased Torque Gain MPPT Algorithm of Wind Turbine with Consideration of Pitch Angle Adjustment

Abstract

Wind turbines can improve wind energy capture efficiency by decreased torque gain (DTG) algorithm for maximum power point tracking (MPPT), but it will cause greater tracking loss during the deceleration process of tracking the weakening wind speed. Existing research shows that the wind energy capture can be improved by adjusting the pitch angle in the dynamic process of maximum power point tracking using the traditional power curve algorithm. The essence of adjusting the pitch angle of the wind turbine in the MPPT stage to improve the efficiency is to correct the operating angle of attack (AOA) of the wind turbine to its optimal value. Since DTG algorithm improves the acceleration performance of the wind turbine, its operating AOA approaches the optimal AOA during the acceleration stage, but at the same time, the weakened deceleration performance also causes the operating AOA to more deviate from the optimal AOA during the deceleration process. Therefore, this paper proposes an improved decreased torque gain MPPT algorithm with consideration of pitch angle adjustment. Aiming at the problem that the wind turbine more deviates from the optimal AOA during the deceleration process of DTG algorithm, the optimal pitch angle adjustment is performed during the deceleration process of the wind turbine to correct its operating AOA to the optimal value to reduce the tracking loss of wind energy. In the FAST software, taking the 600kW CART3 wind turbine of the National Renewable Energy Laboratory (NREL) in the United States as an example, the effectiveness of the proposed strategy is verified by the turbulent wind speed sequence.