一种适用于模块化多电平换流器的多阶段模型预测控制方法

A Multi-stage Model Predictive Control Method for Modular Multilevel Converter

模块化多电平换流器(MMC)具有可扩展性强、输出电能质量高等优点,在电能传输领域受到了广泛的关注。针对传统模型预测控制权重因子设计复杂、桥臂环流谐波分量大等问题,文中提出了一种多阶段模型预测控制(MSMPC)方法。所提出MSMPC方法包括三个阶段:1)第一阶段获得输出电流跟踪的参考控制选项,实现交流电流控制;2)第二阶段通过引入两个环流因子来计算前阶段控制中上、下桥臂的子模块(SMs)的最优数量;3)第三阶段提出一种子模块预测电压分组排序方法,可有效减少电压排序次数和降低开关频率。与传统的MPC方法相比,所提出的MSMPC方法避免了权重因子设计,提高了环流抑制的性能,同时降低了控制器的计算量。通过仿真和实验结果验证了所提MSMPC方法的有效性。

Modular multilevel converter(MMC)has received extensive attention in the field of power transmission because of its advantages of strong scalability and high output power quality.A multi-stage model predictive control(MSMPC)method is proposed to solve the problems of complex weight factor design of traditional model predictive control and large harmonic component of bridge arm circulation.The proposed MSMPC method includes three stages:1)In the first stage,the reference control option of output current tracking is obtained to realize AC current control;2)In the second stage,two circulation factors are introduced to calculate the optimal number of sub modules(SMs)of the upper and lower bridge arms in the control of the previous stage;3)In the third stage,a sub module predictive voltage grouping sorting method is proposed,which can effectively reduce the number of voltage sorting and switching frequency.Compared with the traditional MPC method,the proposed MSMPC method avoids the design of weighting factors,improves the performance of circulating current suppression,and reduces the computational load of the controller.Simulation and experimental results verify the effectiveness of the proposed MSMPC method.