基于MPC的MMC-HVDC子模块均压控制策略

Sub-module Voltage Balanced Control Strategy of MMC-HVDC Based on Model Predictive Control

模块化多电平换流器(Modular Multilevel Converter,MMC)具有效率高、谐波小、模块化设计和易级联等优点,在高压大容量电能变换领域得到了广泛应用。为提高基于模块化多电平换流器的直流输电系统(MMC-HVDC)运行的动态响应速度,提出了一种基于模型预测控制(Model Predictive Control,MPC)与改进的子模块均压控制策略相结合的方法,通过预测模型、反馈校正和滚动优化得到最优的电压控制量,克服了传统的内环电流控制器与外环控制器中PI参数整定困难和动态响应慢的问题。最后,在PSCAD-EMTDC软件平台搭建了21电平的MMC-HVDC系统仿真模型。仿真结果验证了控制策略的有效性和可行性。

The modular multilevel converter （MMC） has the advantages of high efficiency,low harmonic,modular design and easy cascade,has been widely used in the field of high voltage and large capacity energy conversion. In order to improve the dynamic response speed of the MMC-HVDC based on the modular multi-level converter,a novel method combining a model predictive control （MPC） of MMC-HVDC system with improved sub-module voltage balanced control strategy was proposed in this paper. The method utilized the prediction model,feedback correction and rolling optimization to obtain the optimal voltage control,and overcame the difficulties in the traditional way of setting PI parameters of the internal loop current controller and the outer loop controller and tackles the problem of low dynamic response. Finally,a 21-level MMC-HVDC system simulation model was built by PSCAD-EMTDC software platform.The simulation results showthe effectiveness and feasibility of the control strategy.