Parameter Optimization To Frequency Regulator Of DFIGs To Improve Wind Power System Transient Stability

The frequency regulation control of doubly-fed induction generator(DFIG)not only improves the power system frequency stabilities,but also affects the power system transient stability.The parameters of low pass filters for DFIG frequency control affect the active power output of the DFIGs during the transient process,which in turn affects the transient angular stabilities,therefore,it is possible to improve the transient stability of the wind power system by tuning this parameter.This paper expands the trajectory sensitivity and adjoint sensitivity methods to optimize the parameters of low-pass filters for DFIG frequency regulation control.The main research content involves:(1)Model SG and DFIG in detail,derive DFIG reserve and inertial cooperative frequency regulation control algorithm,and construct DFIG grid-connected power system.With the load disturbance and three-phase fault,the effects of DFIG frequency regulation control on system frequency characteristics and transient stability are analyzed by time-domain simulation.(2)Extend the trajectory sensitivity to the DFIG grid-connected power system,derive the trajectory sensitivity equation of the wind power system to the parameters of low-pass filters for frequency regulation control,and quantify the impact of these parameters on the system's dynamic performance.With the object of the integral of the relative error of the mechanical power deviation of the SGs,the gradient information is obtained by the trajectory sensitivity analysis.then the low-pass filter parameters are optimized using the interior point method to improve the system transient stability.(3)In order to overcome the shortcomings of the trajectory sensitivity algorithm that requires multiple transient simulations when optimizing multiple parameters,expand the adjoint sensitivity to the DFIG grid-connected power system,derive the adjoint dynamic equations to solve the Lagrange multipliers,and obtain gradient information to optimize parameters of low pass filters to improve power system transient stability.(4)Compare and verify the optimization algorithms based on the two dynamic sensitivities,and explore the advantages and disadvantages of the two algorithms.