基于改进LQR的交直流低频振荡协调控制策略

摘要

In light of the increasingly serious problem of low-frequency oscillations in AC/DC hybrid power grid,a new strategy based on an improved linear quadratic regulator(LQR)is proposed to coordinate power system stabilizer (PSS)and DC additional controller. Genetic algorithm(GA)is used to optimize the weight matrixes Q and R in the LQR method to realize the best control performance.In the meantime,according to the concept of multi-area control, total least squares-estimation of signal parameters via rotational invariance technique(TLS-ESPRIT)is used to analyze the low-frequency oscillation characteristics of the whole system at first,and the improved LQR control method with an observer is designed to suppress the low-frequency oscillation in the intra-area.After the oscillation damp in the intra-area satisfies the requirements,the same method is adopted again to design a DC additional controller to suppress the low-frequency oscillation in the inter-area.Finally,simulation results show that the proposed design method for the con?troller can effectively suppress the low-oscillations of the whole system,and it also has certain robustness.%针对交直流混合大电网日益严重的低频振荡问题,提出了一种基于改进线性二次型最优控制的新策略以使电力系统稳定器和直流附加控制器协调运行.该方法采用遗传算法对线性二次型最优控制的权矩阵Q和R进行优化使其控制效果最优.同时采用分区域控制思想,首先利用总体最小二乘-旋转不变辨识技术分析全系统低频振荡特性,用带观测器的改进线性二次型最优控制方法对抑制区域内低频振荡的电力系统稳定器进行设计.当区域内振荡阻尼满足要求后,再次采用相同方法设计出抑制区域间低频振荡的直流附加控制器.仿真结果表明,所提控制器设计方法能更有效地抑制全系统低频振荡,且具有一定的鲁棒性.