Optimal gust wind energy capture using critical tracking frequency for wind turbines

Gusty wind in urban areas contains significant energy potential that can be harnessed, but the existing wind turbine rotor speed control systems based on continuous wind speed tracking have a noticeable response delay as compared to the duration of the common short gusts, inducing a significant deficit in harnessed excess energy content (EEC) from gusty wind. This work scrutinizes the energy content distribution among the gusty wind components and their differential impacts on the control response to identify factors to improve response timeliness. Cross-correlation spectrum analysis between the wind turbine response and the local wind spectrum was used to identify the critical tracking frequency that can significantly reduce the average response delay of wind turbines in gusty wind conditions while maximizing the gust energy harvesting ability was developed and validated by various time-domain simulation results. Combining the critical tracking frequency with the theoretical estimation of the EEC of a wind turbine, the expected EEC harnessing ability of a wind turbine can be estimated before installation. For the sample Savonius wind turbine in this work, the response delay of the wind turbine was shortened by 65%, leading to 25% more harnessed EEC from gusty wind.