Adaptive Frequency Regulation Control Strategy Of Wind Turbine

With the gradual depletion of fossil energy and the aggravation of environmental problems,new energy power generation has received more and more attention.However,as the installed capacity of new energy power generation continues to increase,the inertia level of the power system continues to decrease,resulting in the weakening of the power support capacity of the power system.Therefore,it is necessary to take control strategies to enable the wind turbine to provide active support.On the one hand,when an emergency power reduction event occurs in the high-proportion new energy power system,such as the fault of the interconnection line in the power system,which results in a large active power shortage in the system,the wind turbine must adaptively adjust the active output according to its own frequency regulation ability,and quickly release a large amount of energy for emergency power response.On the other hand,when the power fluctuation occurs in the high-proportion new energy power system,the fixed coefficient control strategy cannot fully exert the frequency regulation potential of the wind turbine,and cannot fully utilize the rotor kinetic energy to participate in the system frequency regulation;furthermore,the fixed coefficient control strategies may lead to excessive participation of wind turbine in grid frequency regulation,making the wind turbine speed exceed the limit,which is not conducive to the frequency safety of the power system.Therefore,it needs to study the adaptive frequency regulation control strategy of wind turbine according to the dynamic change of frequency regulation capacity of the wind turbine,so as to give full play to the frequency regulation ability of wind turbine and improve the frequency security of the system.In view of the above problems,this paper takes the Doubly-fed induction generator as the main research object to carry out in-depth research on the adaptive frequency regulation control strategy of wind turbine generator.The specific research contents are as follows:Aiming at the problem of insufficient system active power support capacity in the emergency power reduction event in a high proportion of new energy power systems,this paper proposes an adaptive power response strategy for wind turbine based on torque limit,which can enable wind turbine to quickly release a large amount of energy to participate in emergency power response.In this paper,the frequency regulation capability of the wind turbine is analyzed firstly,and then the operation characteristics and torque limit power of the wind turbine are analyzed.According to the characteristic that the torque limit power changes adaptively with the rotor speed,the adaptive frequency response of the wind turbine based on the torque limit is further studied.Finally,the simulation verifies that the output power is increased to the torque limit power after the proposed strategy is triggered,and the reference value of the output power is large.It can effectively deal with the emergency power reduction event of the power system.Aiming at the problem that the fixed coefficient droop control cannot release the rotor kinetic energy for power support according to the actual operation of the system,this paper proposes an adaptive droop control strategy based on fuzzy control.Firstly,the basic principle of fuzzy control and the design of fuzzy controller are analyzed.Secondly,a fuzzy controller with wind speed and frequency deviation as input and droop control frequency regulation coefficient as output is designed.Finally,the simulation verifies that the proposed strategy can adaptively increase the frequency regulation coefficient and make full use of the rotor kinetic energy of wind turbine for inertia response when the wind speed and frequency deviation increase.The frequency response effect of the power system is effectively improved.Aiming at the problem that the fixed coefficient control strategy may cause the rotor speed of wind turbine and the state of charge of the energy storage system to exceed the limit,this paper proposes an adaptive frequency regulation coefficient control strategy based on Butterworth function.Firstly,frequency response strategy based on droop control of wind turbine and virtual inertia control of energy storage system is proposed.Secondly,the frequency response analysis of power system with wind-storage system is carried out,and then the adaptive frequency regulation coefficient control strategy based on Butterworth function is proposed.Finally,the simulation verifies that when the rotor speed of wind turbine and the state of charge of energy storage system are low,the strategy proposed in this paper can reduce the frequency regulation coefficient by reducing the frequency regulation factor,thus reducing the frequency regulation power of the wind-storage system,which is conducive to avoiding the rotor speed of wind turbine and state of charge of energy storage system exceeding the limit,and improving the protection ability of the wind turbine and energy storage to itself.