基于MMC的电机驱动新型控制方法

针对电机在低频工况下出现的电容电压波动、桥臂环流等问题，提出了一种无权重系数的模块化多电平变换器(Modular Multilevel Converter ，MMC)驱动模型预测控制策略。在假设子模块(Submodule，SM)电容电压均衡的前提下，建立相电流目标函数并求取最优解，通过引入补偿电平数，实现对环流的优化控制。同时为改善传统排序均压控制算法速度较慢的不足，优化了现有SM电容均压控制策略，引入保持因子，并依据理想情况下MMC的电容电压规律，进行归并排序，保证了MMC中各SM电容电压的均衡。通过仿真验证了所提方法能有效实现对电机的控制。

Model predictive control strategy of MMC with weight-free coefficients

Aiming at the problems of capacitor voltage fluctuation and bridge arm circulating current in the motor at low frequency, a predictive control strategy of MMC drive model without weight coefficient was proposed. On the premise that the sub-module capacitor voltage was balanced, the phase current objective function was established and the optimal solution was obtained, the optimal control of circulating current was realized by introducing the number of compensation levels. At the same time, in order to improve the slow speed of traditional sorting voltage sharing control algorithm, the existing sub module capacitor voltage sharing control strategy was optimized, and the protection factor was introduced. According to the capacitor voltage rule of MMC under ideal conditions, the merging and sorting were carried out to ensure the balance of capacitor voltage of each sub module in MMC. The simulation results showed that the proposed method can effectively control the motor.