基于变结构控制理论的高压直流附加频率控制器设计

摘要

针对因故障扰动或负荷投切引起电力系统频率振荡的问题,提出一种基于变结构控制理论的高压直流附加频率控制器设计方法.利用TLS-ESPRIT算法辨识出系统的低阶线性化模型;基于二次最优型的变结构控制原理设计高压直流附加频率控制器,通过直流功率的快速调节来抑制交流系统中因功率不平衡引发的频率振荡;利用极大极小值原理和改进粒子群优化算法对控制器参数进行优化.在PSCAD/EMTDC中搭建某实际电网模型进行仿真验证,并与传统PI控制器进行对比分析.仿真结果表明所提控制器对不同故障引发的系统频率振荡都具有更好的抑制效果,能明显提升系统频率稳定性,且具有较强的鲁棒性.%Aiming at frequency oscillation problem caused by fault disturbance or load switching in power system,a design method of HVDC additional frequency controller based on variable structure control theory is proposed.The low-order linear model of the system is identified using TLS-ESPRIT algorithm,the HVDC additional frequency controller is designed based on quadratic optimal variable structure control,the frequency oscillation caused by unbalanced power in AC system is suppressed by fast regulation DC power,and the controller parameters are optimized with minimax principle and improved particle swarm optimization algorithm.A simulation model of a real power grid is set up by PSCAD/EMTDC to compare the proposed controller with the traditional PI controller.Simulative results show that the proposed controller can better suppress the system frequency oscillation caused by different faults and significantly improve the system frequency stability with strong robustness.