关键词: 双馈异步风力发电机, 降阶矢量比例积分控制器, 电流谐波, 谐波滤除, 闭环控制

Abstract: In order to filter out the harmonics of the impact current of offshore wind power grid connection to the maximum extent and maintain the smooth operation of the offshore wind power system, a method for filtering out the harmonics of the impact current of offshore wind power grid connection based on vector proportional integral controller was proposed. A reduced order vector proportional integral controller ( ROVPI ) was designed, the reference value of impulse
harmonic current in offshore wind power grid connection was calculated, and a closed-loop control structure was constructed. The response value of the system to current harmonics was calculated through closed-loop control transfer function. Using a reduced order vector proportional integral controller, harmonic filtering was achieved based on the response value of the transfer function. The test results showed that the closed-loop feedback control structure designed achieved a phase response of ± 100° and a maximum frequency amplitude of - 20 ~ 80 dB ( A ) , which has stronger adjustment ability compared to traditional open-loop control. After filtering out harmonics, the current remains at -0. 25 ~ 0. 25 A, making the current more uniform and the power fluctuation less than 1 MW, which helps to ensure the smooth operation of offshore wind systems.

Key words: doubly fed induction generntor( DFIG), reduced order vector proportional integral controller ( ROVPI), current harmonics, harmonic filtering, closed loop control