电压源高压直流输电离散模型及其控制策略

针对电压源高压直流输电(VSC-HVDC)数字离散控制系统，推导了dq同步旋转坐标系下的VSC-HVDC的离散状态空间模型，研究了其离散电流内环控制器和外环控制器模型。为补偿离散模型的采样延时，提出基于Smith状态预估器的电流内环控制策略，并根据预估信号误差提出基于估计误差增益反馈的改进Smith状态预估器控制并应用于电流内环控制。基于电磁暂态仿真软件PSCAD/EMTDC建立了VSC-HVDC模型及其离散化控制器模型。仿真结论验证了离散模型的正确性以及控制策略的有效性。

Study of VSC-HVDC Discrete Model and Its Control Strategies

According to the digital discrete control system of HVDC based on voltage source converter (VSC-HVDC), the discrete model is derived in synchronous dq reference frame. The inner-loop current discrete controller and the related outer loop controller of VSC-HVDC are developed according to the discrete model. In order to compensate the sampling delay of discrete model the inner-loop current controller based on Smith predictor is also presented, and an improved Smith predictor based on estimation error feedback gain in inner loop controller is also developed. The correctness of discrete model and the validities of control strategies are verified by PSCAD/EMTDC simulation.