基于电容电压波动补偿的混合型模块化多电平变换器

为了降低模块化多电平变换器的电容体积,文中提出一种基于电容电压波动补偿混合子模块的模块化多电平变换器。首先,介绍所提混合型模块化多电平变换器的系统结构与减小电容体积的机理,同时对混合子模块的投切原则进行详细分析;然后,通过分析混合子模块内部不同电容的能量波动,给出所有电容的容值设计方法,并与传统的半桥型模块化多电平变换器进行对比;最后,通过仿真与实验验证了所提方案的有效性。结果表明,文中提出的混合型模块化多电平变换器能够以较低的开关器件成本,大幅度提高电容能量利用率,降低模块化多电平变换器子模块电容的体积,实现系统功率密度的提高。

A hybrid modular multi-level converter based on capacitor voltage ripple compensation

In order to reduce the capacitor volume of the modular multi-level converter,a modular multi-level converter with the hybrid submodule based on capacitor voltage ripple compensation is proposed. Firstly,the system structure of the proposed hybrid modular multi-level converter and the mechanism of reducing the capacitor volume are introduced,and the switching principle of the hybrid submodule is analyzed in detail. Secondly,the energy fluctuation of capacitors is analyzed to size the capacitance of all capacitors,and the overall capacitor volume is evaluated and compared with the conventional half-bridge modular multi-level converter. Finally,the effectiveness of the proposed structure and control is verified by simulation and experimental results. The results show that the proposed structure in this paper can greatly enhance the energy utilization ratio of the capacitors in the modular multi-level converter with lower switching device cost,thus,reducing the capacitor volume and improving the system power density.