Maximum power point tracking control for wind turbines based on tracking low-frequency wind speeds

• The relationships between wind speed frequency and wind energy capture and electromagnetic torque are derived. • The designed controller based on the resonance principle can purposefully strengthen the tracking capability of low-frequency wind speed. • The improved MPPT strategy not only effectively increases power generation efficiency but also significantly mitigates drive-train load. To increase power generation efficiency, the torque compensation methods according to optimal torque curve speed up the maximum power point tracking process by enhancing the tracking capability of wind turbines (WT) in response to variable wind speeds. Nevertheless, these methods simultaneously cause significantly increased drive-train load, affecting the service life of WT. To solve this problem, the mathematical relationships between wind speed frequency, power generation efficiency, and electromagnetic torque are analyzed. It is found that excessively tracking high-frequency wind speed is the main reason for this problem, and focusing on tracking low-frequency wind speed not only results in negligible power generation efficiency losses but also significantly mitigates drive-train load. Therefore, a maximum power point tracking control method for wind turbines based on tracking low-frequency wind speed is proposed. The proposed method designs the amplitude-frequency characteristic curve of the WT system based on the resonance principle, which exhibits high gain exclusively in the low-frequency range. This design strengthens the tracking capability of low-frequency wind speed, thereby focusing on tracking low-frequency wind speeds. Then, the experiments show that the proposed method not only effectively increases power generation efficiency but also significantly mitigates drive-train load.