非理想条件下MMC-PET非线性复合控制策略

Nonlinear Composite Control Strategy of MMC-PET Under Non-Ideal Conditions

由于模块化多电平变流器(modular multilevel converter,MMC)电力电子变压器(power electronic transformer,PET)使用传统的控制策略难以保证系统运行时的动态性能,在电网处于不平衡时使得控制难度进一步增加。为了提高系统的动态性能,提出了一种非线性的反馈线性化滑模复合控制策略。该复合控制策略将反馈线性化控制(feedback linearization control,FLC)和滑模控制(sliding mode control,SMC)的优势结合在一起实现优势互补。首先,建立了MMC-PET整体仿真模型;其次,通过数学模型建立反馈线性化滑模控制的控制模型;最后,利用仿真与实验平台进行仿真对比实验,将所提复合控制策略与单一的反馈线性化控制、滑模控制以及常用的PI控制作了仿真对比,以验证所提控制策略可以在外部扰动时具有良好的动态性能和较好的鲁棒性等优势。

Due to the traditional control strategy used in modular multilevel converters and power electronic transformers,it is dif⁃ficult to ensure the dynamic performance of the system during operation,which further increases the difficulty of control when the power grid is in imbalance.In order to improve the dynamic performance of the system,a nonlinear feedback linearization sliding mode composite control strategy is proposed.This composite control strategy combines the advantages of feedback linearization control(FLC)and sliding mode control(SMC)to achieve complementary advantages.Firstly,an overall simulation model for modular multilevel converters power electronic transformers(MMC-PET)is established.Secondly,a control model for feedback linearization sliding mode control is established through a mathematical model.Finally,a simulation comparison experiment is conducted using a simulation and experimental platform to compare the proposed composite control strategy with a single feedback linearization control,sliding mode control,and commonly used PI control,in order to verify that the proposed control strategy has good dynamic performance and robustness under external disturbances.