计及转速限值的双馈风机变下垂系数控制策略

Variable droop coefficient control strategy of a DFIG considering rotor speed limit

传统的下垂控制策略在整定调频系数时更多关注双馈风机本身的运行状态,较少考虑风电渗透率和系统扰动变化对风机调频过程的影响,控制方法的适应性有待提高。为此,建立了风电参与调频的电力系统频率响应模型,提出了计及转速限值的双馈风机下垂系数整定方法及控制策略。通过推导调频过程转子转速的极小值和稳态值,确定出使风机转速自行稳定且不触发保护下限的下垂系数范围。然后根据扰动的大小在线调整控制参数,避免风机发生过度响应。在DIgSILENT中建立了系统仿真模型。仿真结果表明所提策略能够有效应对不同的系统扰动情况,保证风机自身运行的稳定性。

Traditional droop control strategy pays more attention to the operational state of Doubly-Fed Induction Generators(DFIGs)when setting frequency modulation coefficients,and less to the influence of wind power permeability and system disturbance on the wind turbine frequency regulation process.The adaptability of the control method needs to be improved.For this reason,a frequency response model of a power system with wind power participating in frequency regulation is established,and the setting method and control strategy of the droop coefficient of DFIG considering a speed limit value are proposed.By deducing the minimum and steady value of rotor speed in the process of frequency regulation,the droop coefficient range which makes the DFIG speed self stabilize,and does not trigger the protection lower limit value,is determined.According to the size of the disturbance,the control parameters are adjusted online to avoid excessive response of the DFIG.A system simulation model is established in DIgSILENT.The simulation results show that the proposed strategy can effectively deal with different system disturbances and ensure the stability of the DFIG itself.