基于电压源换流器的高压直流输电系统离散化建模与仿真研究

Discretization Modeling and Simulation Study of HVDC Power Transmission System Based on Voltage Source Converters

基于电压源换流器的高压直流输电(voltage source converter based high voltage direct current transmission,VSC-HVDC)的工业控制系统通常为微机控制器,该控制器的控制对象是系统的离散化模型。为此提出了一种在dq0同步旋转坐标系下的VSC-HVDC离散化状态空间模型。在此基础上建立了VSC电流内环离散化控制器和外环控制器,并实现了有功电流和无功电流的解耦控制;为提高VSC-HVDC的外环控制器响应速度,在外环控制器中引入了前馈控制。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。仿真结果验证了离散模型的正确性以及控制策略的有效性。

Minicomputer controllers are usually used in the industrial control systems of voltage source converter based high voltage direct current transmission （VSC-HVDC） and the controlled objects are discretized models of VSC-HVDC. For this purpose a discretized state space model of VSC-HVDC under d-q-0 synchronous rotating coordinate system is proposed. On this basis the inner-loop current discrete controller and the outer-loop controller of VSC are built and the decoupling control for active and reactive currents are implemented. To accelerate the response speed of outer-loop controllers of VSC, the feed-forward control is led into outer-loop controller. Based on electromagnetic transient simulation software PSCAD/EMTDC, a VSC-HVDC model and a model for its discretized controller are built. Simulation results verified that the proposed discretized model is correct and the control strategy is effective.