交直流混联系统非线性自适应广域附加控制器的设计

Design of a nonlinear adaptive wide-area supplementary controller for an AC/DC hybrid power system

为了提高交直流混联系统的暂态稳定性,设计了基于高压直流输电(High Voltage Direct Current,HVDC)大信号调制方式的非线性自适应广域附加控制器(Nonlinear Adaptive Wide-area Supplementary Controller,NAWSC)。该控制器利用扰动观测器估计和补偿实际系统中的非线性动态,无需精确模型,解决了模型不确定时稳定控制措施不易设计的难题。同时,该控制器通过整合广域功角信息得到的系统等值功角进行输出反馈,直接实现暂态稳定控制。在四机两区域交直流混联系统和10机39节点交直流混联系统中进行仿真。结果表明:在不同运行工况下,NAWSC相对于比例积分型广域附加控制器具有更好适应性;在参数不确定下,NAWSC相对于基于精确模型的反馈线性化广域附加控制器具有更好的控制鲁棒性。所设计NAWSC可以提高HVDC暂态调节能力。

To improve the transient stability of an AC/DC hybrid grid,this paper designs a Nonlinear Adaptive Wide-Area Supplementary Controller(NAWSC)based on the large signal modulation of High Voltage Direct Current(HVDC).Without an accurate model,the proposed controller can directly estimate and compensate for the nonlinear dynamics in the actual system using a disturbance observer.It can also tackle the problem that it is difficult to design corresponding control measures when the model is uncertain.Equivalent wide-area power angle information is used for output feedback to realize transient stability control directly.Two case studies are undertaken based on a four-machine two-area AC/DC hybrid grid and a 10-machine 39-bus AC/DC hybrid system.The simulation results show that compared with a proportional integration wide-area supplementary controller,NAWSC possesses better adaptability under different operating conditions.When the uncertainty of parameters is taken into account,NAWSC possesses better control robustness compared with a feedback linearized wide-area supplementary controller.Based on the accurate model,NAWSC can improve the transient regulation capability of HVDC.