Frequency Dynamics-Constrained Parameter Design for Fast Frequency Controller of Wind Turbine
Junkai Huang, Zhifang Yang, Juan Yu, Linyun Xiong, Yan Xu
Abstract
During frequency controller design, the system frequency dynamic behavior is normally assessed by a system frequency response (SFR) model, which is a linearized low-order model that can be efficiently handled. Existing SFR models for a system with wind turbines cannot precisely characterize the nonlinear dynamic of fast frequency controllers in these turbines, causing inaccurate evaluation of the system frequency behavior that may lead to undesired design of fast frequency control parameters. To deal with this issue, the linearization error of the SFR model is formally analyzed. A compensation strategy is proposed to guarantee the accuracy of the frequency behavior assessment. Further considering that fast frequency controllers potentially degrade the small-signal rotor angle stability, this paper presents a coordinated parameter optimization model of fast frequency controllers, which guarantees the system frequency behavior while meeting the small-signal rotor angle stability requirement. Case studies validate the effectiveness of the proposed method.