柔性直流输电系统含有积分稳定环节的无源控制系统设计

摘要

Voltage source converter based high-voltage direct-current (VSC-HVDC) transmission system is a nonlinear, strongly-coupled,multiple-input and multiple-output system.The control system of VSC-HVDC transmission system is hard to remain globally asymptotically stabilized while eliminating the steady-state error.Based on the port-controlled Hamilton system with dissipation(PCHD) model of the VSC-HVDC transmission system,a method of interconnection and damping assignment passivity based (IDA-PB) control with integral stabilization action is presented.According to the control principle, three typical IDA-PB control schemes and the value range of their control parameters are given.For the exponential stability type IDA-PB control scheme,whose performance in the three is best,an integral stabilization action is added to the controller using the integral stability theorem.By installing the new controller,the VSC-HVDC transmission system has not only improved steady and transient characteristics, but also remained globally asymptotically stabilized, while the system is subj ected to large disturbance or the system parameters cannot be accurately obtained.It is convenient to design the controller without solving partial differential equations.Simulation results performed by PSCAD/EMTDC show that the steady and transient state performance is improved compared with the proportional-integral(PI)controller.More accurate,effective,and robust,the IDA-PB controller is insensitive to parameter changes. This work is supported by National High Technology Research and Development Program of China (863 Program) (No.2012AA052701).%电压源换流器型高压直流(VSC-HVDC)输电系统具有非线性、强耦合、多输入等特点,其控制系统往往难以在消除稳态误差的同时,依然保持全局渐近稳定。基于 VSC-HVDC 输电系统的端口受控耗散哈密顿(PCHD)模型,提出了一类具有积分稳定环节的互联和阻尼配置的无源(IDA-PB)控制方案的设计方法,并依据控制原理给出了3种具有典型性的控制方案及其控制参数的取值范围。对于其中性能最优的指数稳定型IDA-PB控制方案,利用积分稳定性定理,在其控制器中加入积分稳定环节,使得系统在受到大干扰或是系统参数无法精确预知时,具有良好的稳态、暂态特性的同时,依然保持全局渐近稳定。控制系统的设计过程中,无需求解偏微分方程,大大简化了计算量。PSCAD/EMTDC环境下的仿真表明,与传统比例—积分(PI)控制相比,IDA-PB控制策略能显著提高系统稳态、暂态性能,响应速度快、跟踪精度高,且对参数变化不敏感,有优良的鲁棒性及全局稳定性。