基于电压源换流器的高压直流输电小信号动态建模及其阻尼控制器设计

基于电压源换流器(VSC)和脉宽调制(PWM)技术的新型高压直流输电(VSC-HVDC)，具有快速、灵活的有功功率和无功功率控制能力，能够改善系统的稳定性。文中建立了VSC-HVDC的小信号动态模型，该模型包括VSC与交流系统接口的线性化方程、VSC-HVDC内部直流系统动态过程的线性化方程以及控制系统线性化方程3个部分，具有一般性。以VSC的有功功率整定值为输入，VSC-HVDC并联交流输电线路的有功功率为输出，通过对系统频率响应的辨识，得到了两者间的开环传递函数。在此基础上，利用极点配置技术，设计了单输入单输出结构的VSC-HVDC附加阻尼控制器。对一VSC-HVDC/AC交直流并联输电系统特征根的分析及非线性仿真表明，配备该阻尼控制器的VSC- HVDC能有效地抑制系统低频振荡，增加系统阻尼。

Small Signal Dynamic Modeling and Damping Controller Designing for VSC Based HVDC

Voltage source converter (VSC) based HVDC (VSC-HVDC) is a new transmission technology which can improve the power system stability with its fast and independent capability to control the active and reactive power. The small signal dynamic model of VSC-HVDC is established in this paper. This model is general for including three parts, i.e., the small signal model for VSC, for VSC-HVDC inner dc system and for control system of VSC-HVDC. Taking the VSC's active power reference as input signal and active power of VSC-HVDC parallel ac line as output signal and using the system identification method, the opened-loop transfer function between the two signal is got from their frequency response. Based on the opened-loop transfer function, VSC-HVDC damping controller is designed in terms of pole assignment technology. Eigenvalue analysis and nonlinear simulation for a VSC-HVDC/AC parallel system verify that VSC-HVDC equipped with the designed damping controller can suppress the low frequency oscillation effectively