基于小干扰动态模型的LCC-HVDC系统控制器参数优化方法

Controller Parameters Optimization Method for LCC-HVDC System Based on Small-Interference Dynamic Model

为了改善电网换相换流器高压直流(line commutated converter-high voltage direct current,LCC-HVDC)输电系统的动态响应性能,提出了一种基于小干扰动态模型与传递函数模型的控制器参数优化方法,采用粒子群优化算法对全系统的控制器参数同时进行优化。首先,建立了计及锁相环输出相位与交流母线电压实际相位差异的双端LCC-HVDC输电系统的小干扰动态模型,仿真结果验证了该小干扰动态模型的准确性;然后,基于根轨迹法,获取了致使系统小干扰失稳的控制器参数临界值;最后将小干扰动态模型转换为传递函数模型,应用粒子群优化算法,以时间乘绝对误差积分指标为目标函数,对所有控制器参数进行了优化。仿真结果表明优化后系统动态响应性能有所改善。

In order to improve the dynamic response performance of LCC-HVDC transmission system,a controller parameter optimization method based on small-signal dynamic model and transfer function model is proposed.Firstly,a small-signal dynamic model of double-terminal LCC-HVDC transmission system considering the difference between the output phase of the PLL and the actual phase of the AC bus voltage is established,and the simulation results verify the accuracy of the small-signal dynamic model.Based on the root trajectory method,the critical value of the control parameter that causes the instability of the system with small disturbance is obtained.Finally,the small-signal dynamic model is transformed into the transfer function model,and the particle swarm optimization(PSO)algorithm is applied to optimize all the controller parameters by taking the integral of time multipled by the absolute value of error(ITAE)index as the objective function.The simulation results show that the dynamic response performance of the system is improved after optimization.