MMC-HVDC的二阶线性自抗扰控制策略

基于模块化多电平换流器的高压直流输电(MMC-HVDC)技术已得到广泛运用,但传统基于dq同步旋转坐标系的双闭环PI控制中电流内环需要依赖系统数学模型进行前馈解耦补偿,并且一阶非线性自抗扰控制器设计参数过多、整定困难。针对上述问题,提出了MMC-HVDC的二阶线性自抗扰控制策略。设计了MMCHVDC的双闭环二阶线性自抗扰控制器,实现了有功和无功功率的完全解耦控制,所设计控制器还具有响应速度快、抗扰能力强以及不依赖被控对象数学模型等优点;为了降低桥臂子模块的开关次数,改进了子模块电容电压平衡控制算法;在PSCAD/EMTDC中搭建了21电平MMC-HVDC的电磁暂态仿真模型,通过仿真验证了所设计控制器具有良好的控制性能和电容电压平衡控制算法的有效性。

Second-order linear active disturbance rejection control strategy of MMC-HVDC

The technology of MMC-HVDC(Modular Multilevel Converter based High Voltage Direct Cur-rent) has been widely applied. However, the current inner-loop, which is based on traditional dq synchronous rotating coordinate system in the dual closed-loop PI control system, relys on the systematic mathematical model for the feed-forward decoupling compensation. Moreover, the first-order nonlinear active disturbance rejection controller has a considerable number of design parameters to tune. In these regards, the second-order linear active disturbance rejection control strategy of MMC-HVDC is proposed. The dual closed-loop second-order linear active disturbance rejection controller of MMC-HVDC is designed to achieve the complete decoupling control of active and reactive power. Besides, the designed controller has fast response speed, strong anti-disturbance ability, and independence of controlled object mathematical model. Then, an improved capacitor voltage balancing control algorithm is proposed to reduce the switching frequency of bridge submodule. The electromagnetic transient model of 21-level MMC-HVDC is built in PSCAD/EMTDC, and simulative results verify that the proposed controller has good control performance and the capacitor voltage balancing control algorithm is effective.