中文摘要：

为改善模块化多电平永磁同步电机驱动系统的控制性能,对变换器的双星半桥型拓扑结构进行改进,并建立上桥臂和下桥臂中子模块电容电压可变控制的原理分析模型,提出一种根据电机运行速度灵活调节变换器电容电压的新型控制策略,与传统控制方法下变换器的电容电压恒定相比,此新型策略为驱动系统多增加了一维控制量,使系统在灵活性和准确性控制方面得到了明显改善.在实验室中搭建了模块化五电平永磁同步电机驱动系统测试平台,实验结果表明,该新型电容电压控制策略能够有效地控制和调节变换器各个子模块的电容电压,有利于降低系统损耗和改善电机控制性能.

英文摘要：

In order to improve the control performance of permanent magnet synchronous motor（PMSM）drive based on modular multilevel converter（MMC）,a novel capacitor voltage control strategy of MMC applied for PMSM drive was proposed in this paper.With which the capacitor voltage of a sub-module was controlled to high or low flexibly according to the motor speed,and a mathematical analysis model of the flexible control strategy was also developed.Compared with the capacitor voltage stability of the traditional control,the control dimension of the novel control strategy was increased.With the proposed control strategy,the efficiency and precision of the output of the converter could be improved significantly.A laboratory prototype of a five-level MMC-based PMSM drive was built and experiments were carried out.The validity of the control strategy under steady and dynamic states was verified.