基于协同控制理论的非线性直流附加控制器设计

为提高高压直流联络线所连交流系统的暂态稳定性,针对大规模交直流互联电网的非线性及其建模的不准确性,设计了一种新型的基于协同控制的直流附加控制器并将其用于多区域交直流混联系统中。首先根据各区域惯量中心设计合适的宏变量和流形,推导出基于协同控制直流附加控制器的解析表达式;然后以区域惯量中心角频率偏差和直流功率偏差最小为目标函数,采用遗传算法优化控制器参数;最后将所设计的控制器分别用于两区域交直流并联系统和多馈入系统,并采用PSCAD搭建详细模型进行时域仿真。仿真结果表明,与基于极点配置线性化方法和基于滑模控制非线性方法的直流附加控制器相比,提出的协同控制方法具有更好的控制效果,能够有效地抑制区间功率振荡。此外,该控制器的推导对系统模型的依赖性不强,且对不同负荷模型、不同运行方式和广域测量信号的延时具有较强的鲁棒性。

Design of nonlinear HVDC supplementary controller based on synergetic control

Aiming at the nonlinearity of large AC/DC power system and the inaccuracy of its model, a DC supplementary controller based on SGC(SynerGetic Control) is designed and applied to the multi-area AC/DC power system to enhance its transient stability. Appropriate macro-variable and manifold are designed according to the inertia center of each area, the analytic expression of SGC-based DC supplementary controller is deduced, and with the minimum angle frequency offset and the minimum DC power offset of areal inertia center as the objectives, the controller parameters are optimized by genetic algorithm. The designed controller is applied to a two-area AC/DC power system and a multi-infeed AC/DC power system respectively, and the time-domain simulations based on their PSCAD models demonstrate that, the proposed SGC method has better control effect in the inter-area oscillation damping than the conventional pole placement method and sliding mode control method. Furthermore, with strong robustness, the designed controller is immune to load model, operation mode and wide-area measuring signal delay, and its deduction has little dependence on the system model.