连接低惯量系统的柔性直流输电模型预测控制

摘要

针对低惯量系统频率稳定性控制需要,通过对与之相连接的柔性直流输电(VSC-HVDC)系统的数学模型离散化,采用模型预测控制算法分别设计整流器和逆变器的控制系统.模型预测控制方法具有结构简单、参数选择便捷、动态响应快、鲁棒性好等特点,易于实现与VSC-HVDC相连的低惯量送端交流系统频率波动控制.分析基于模型预测控制的直流功率调制对系统频率变化的调节作用,并在 PSCAD/EMTDC仿真软件中建立仿真模型,对比分析传统 PI双环控制直流功率调制方法和模型预测控制直流功率调制方法对交流系统频率的影响,仿真结果表明,VSC-HVDC模型预测控制方法能够有效抑制交流系统频率变化的幅度,加快频率恢复的速度.%Aiming at the need of controlling frequency stability of low inertia system, model predictive control is adopted to design the control systems of rectifier and inverter separately through discretizing the mathematical models of voltage source converter HVDC (VSC-HVDC). This kind of control system has simpler structure, convenient parameter selection, fast dynamic response, and better robustness. It is easy to realize the control of the frequency fluctuation in low inertia sending system connected with VSC-HVDC. The paper analyzed the effects of DC transmission power regulation on frequency power modulation, and set up the simulation model that the low inertia system was connected to VSC-HVDC. Comparative studies were demonstrated between power modulation methods of traditional PI control and model predictive control. The simulation results show that the model predictive control can restrain the range of the frequency change and increase the speed of the frequency recover effectively.