定电压与预测型定关断角控制对HVDC小干扰稳定性的影响

定电压控制和预测型定关断角控制是高压直流（HVDC）逆变站常规的控制方法，合理整定控制器参数可提高交直流系统的小干扰稳定性。文中首先基于开关函数法建立了基于电网换相换流器的高压直流（LCC-HVDC）系统的小干扰动态模型，将其动态响应与电磁暂态模型的动态响应进行对比，验证了小干扰动态模型的正确性。接着，采用特征值及其灵敏度方法分析了LCC-HVDC系统的振荡模式和阻尼特性，对比分析了逆变侧采用定电压控制和预测型定关断角控制时，换流站控制器参数以及交流系统短路比对系统稳定性影响的异同。最后，整定了能维持系统稳定运行的控制器参数稳定域，并通过PSCAD/EMTDC仿真验证了稳定域的正确性。

Influence of Constant Voltage Control and Predictive Constant Extinction Angle Control on Small-signal Stability of HVDC

The constant voltage control and the predictive constant extinction angle control are two conventional control methods for high voltage direct current (HVDC) inverter station. The small-signal stability of AC/DC system can be improved by setting the controller parameters reasonably. Firstly, the small-signal dynamic model of line commutated converter based HVDC (LCC-HVDC) on the basis of switching function method is established, and the correctness of the dynamic model is verified by the comparison of dynamic response between the small-signal model and the electromagnetic transient model. Secondly, based on the eigenvalue and its sensitivity analysis method, the oscillation modes and damping characteristics of LCC-HVDC system are analyzed. When constant voltage control and predictive constant extinction angle control are adopted at the inverter side, the similarities and differences of the influence that the controller parameters of converter station and the short circuit ratio of AC system have on the system stability are compared and analyzed. Finally, the stable region of control parameters which can maintain the stable operation of system is calculated, and the correctness of the stable region is verified by PSCAD/EMTDC simulation.