| With the implementation of the national "double carbon" strategy,the wind power industry has ushered in a new development opportunity period.However,the randomness and intermittence of wind energy lead to the constant switching of wind turbine control mode,which brings many hidden dangers to the stable operation of wind turbine and power grid.Therefore,the research on wind turbine operation control technology is of great significance and engineering application value for improving the wind energy utilization efficiency of a single unit,reducing the output power fluctuation of the unit,and thus ensuring the safe and stable operation of the wind turbine.This paper mainly completed the following research work:(1)The operation principle and basic characteristics of Directly-driven Wind Power with Permanent Magnet Synchronous Generator(D-PMSG)are briefly described.The mathematical model of each part of the unit is established.The vector control strategy of synchronous motor is described,which lays a foundation for the subsequent research of unit operation control technology.(2)The control objectives of different operating intervals of wind turbines are expounded;Aiming at different control objectives in the main operating interval,torque control strategies and variable propeller control strategies are designed respectively to achieve efficient and stable operation of wind turbines in the maximum wind energy tracking interval and constant power control interval.The simulation results verify the effectiveness of the torque and variable propeller control strategy.(3)For the transition interval between maximum wind energy tracking and constant power control of wind turbines,small wind speed fluctuations will cause large fluctuations in the electromagnetic torque of the generator,and then lead to sharp fluctuations in the output power of the unit.Three improved transition interval control strategies are proposed:control strategy based on first-order linear curve,control strategy based on nonlinear curve and control strategy based on Logistic function curve.Combined with the control strategy of the main interval,the integrated control strategy of the output power under the full wind speed of the wind turbine is realized.The simulation results show that the three improved control strategies can effectively reduce the power fluctuation of wind turbines in the transition interval.(4)Considering that the random fluctuation of wind speed near the rated value will lead to frequent switching of wind turbine operation modes and aggravate the output power fluctuation of wind turbine,a weighted switching method of wind turbine operation modes is proposed,and the switching weight is optimized by fuzzy control theory,and a weighted switching controller based on T-S fuzzy reasoning is established.The simulation results show that the proposed weighted switching method has an obvious inhibition effect on the power fluctuation during the unit operation mode switching. |
