基于分数阶重复控制的双馈风机网侧变流器次同步振荡抑制策略OA

Doubly-Fed Induction Generator(DFIG)will lead to Sub-Synchronous Oscillation(SSO)when being connected to the grid through series compensation lines,which seriously threatens the stable operation of power system.In this paper,an improved composite control strategy based on fractional order repetitive control is proposed to solve the problem of DC bus capacitor voltage oscillation caused by SSO.Firstly,the mathematical model of grid-side converter(GSC)in the rotating coordinate system under SSO state is established,and the generation mechanism of sub-synchronous component in DC capacitor voltage is analyzed in detail.Secondly,based on the internal model principle and Lagrange interpolation method,a fractional order repetitive controller(FORC)is designed to accurately track and suppress the harmonic components of non-integer periods through the fractional-order delay link.Then,the stability of the proposed control strategy is verified by Nyquist curve analysis.Finally,the time domain simulation under different wind speed and series compensation conditions is set up to verify the effectiveness of the proposed control method.The simulation results show that the proposed control strategy can quickly suppress SSO and significantly improve the stable operation ability of the doubly-fed wind power system in the series compensation line,compared with the traditional PI control and adaptive quasi-resonant control.