基于同步坐标变换的VSC-HVDC 暂态模型及其控制器

对基于电压源型换流器的新型直流输电系统的暂态数学模型和控制策略进行了研究,建立了同步旋转坐标系下VSC-HVDC系统的暂态数学模型,提出了直接电流控制策略和双闭环控制器结构.内环电流控制器采用电流反馈和电压前馈的解耦控制策略,实现电流的快速跟踪控制;外环控制器由稳态逆模型和PI调节器构成,实现系统有功功率和无功功率的独立调节.最后,基于PSCAD/EMTDC的数字仿真验证了所设计的控制器具有很好的控制性能.

Transient Model and Controller Design for VSC-HVDC Based on Synchronous Reference Frame

The mathematical model and control strategy of the VSC-HVDC system are studied in the paper. The transient mathematical model for the VSC-HVDC system in dq synchronous reference frame is developed,in which direct current control strategy and dual closed loop structure are proposed. Decoupled control structure consisting of current feedback and voltage feed-forward is adopted in the inner current control loop which can track the reference current quickly. The outer loop is power regulators, which combines the inverse steady state model with PI regulator, and can control the active and reactive power separately. Simulation results realized by PSCAD/EMTDC show that the designed control system obtains satisfying performance.