中文摘要：

多电平变流器具有输出谐波小、功率容量大、电磁兼容性好等特性而越来越引起人们的重视.随着超导储能技术的发展,电感储能效率的不断提高,在某些大功率应用场合,电流型逆变器也将发挥出其特定的优点.因此,电流型多电平逆变器拓扑和控制策略的研究具有一定的实际意义.文中提出了一种三相5电平电流型逆变器拓扑,并分析了其工作原理.对多载波PWM控制方法进行简化,采用两个相位相反的三角载波得到3电平信号,经过解耦处理,得到了一种适合于该拓扑的5电平PWM开关控制策略,并进行了仿真验证.最后,建立了一个三相5电平CSI的实验系统,对文中所给的拓扑和控制方法进行了验证.

英文摘要：

Multilevel inverters have been paid more and more attentions because of their good characteristics with low output harmonics, high power capacity, good electromagnetic compatibility and so on. With the development of the superconducting magnetic energy storage （SMES） technology, the energy storage efficiency of inductors can be greatly improved, for higher power applications, current source inverters can have particular advantages in some circumstances. Hence it is useful to explore the topology and control strategy of a multilevel current source inverter （CSI） system. A topology of three-phase 5-level CSI is presented in this paper and its operational principle is analyzed. By simplifying the multicarrier PWM technology, two triangular-carriers out of phase are used to generate 3-level signals, after being decoupled, a kind of 5-level PWM control strategy suited for this topology is obtained and is also testified by simulations. Lastly, an experimental system is built to validate the mechanism of this 5-level topology and its PWM control method.