多端高压直流输电系统自适应无源控制

Adaptive passive control for multi-terminal high voltage direct current systems

本文提出了一种基于扰动观测器的自适应无源控制(perturbation observer-based adaptive passive control,POAPC),并将其用于增加电压源型多端高压直流输电系统(voltage source converter-based multi-terminal high voltage direct current,VSC–MTDC)的阻尼.首先定义一个扰动项,其包含多端口间的相互作用、未建模动态和未知时变外界干扰的综合效应.之后扩展一个虚拟状态来表征该扰动项,进而设计一个扰动观测器对其进行快速在线估计.该方法通过无源化向每个端口注入附加阻尼以改善系统暂态响应,并且不需要精确的系统模型或全局状态测量.基于四端VSC–MTDC系统的4种算例表明:与传统PI控制、无源控制以及基于扰动观察器的滑动模态控制相比,POAPC由于不需要精确系统模型及全局状态测量而具有更高的应用灵活性;在各种运行条件下通过有效减少有功功率P_1和无功功率Q_1控制误差和超调量来获得更优的控制性能;在系统参数不确定场景下将有功功率P_2的峰值变化从11%减少至接近0,鲁棒性更强.

This paper develops a perturbation observer-based adaptive passive control(POAPC), which is applied to improve the system damping of voltage source converter-based multi-terminal high voltage direct current(VSC–MTDC)systems. A perturbation term is firstly defined to aggregate the combinatorial effect of interactions among each terminals,unmodelled dynamics and unknown time-varying external disturbances. Then an extended state is employed to represent the perturbation, which can be rapidly estimated online via a perturbation observer. Furthermore, an extra system damping can be injected into each terminal to improve the transient response through the passivation, while POAPC does not require an accurate system model and measurements of full states. Four case studies are undertaken on a four-terminal VSC–MTDC system, which demonstrate that POAPC can provide a better control performance with greater robustness over that of conventional proportional-integral(PI) control conventional passive control, and perturbation observer based slidingmode control(POSMC). POAPC can effectively reduce the control error and overshoot of active power and reactive power.Meanwhile, its P_2 peak value is reduced from 11% to around 0%, such that a great robustness can be realized.