基于SiC器件的三电平ANPC牵引变流器损耗分析

Design and Loss Analysis of Three-level ANPC Topology Based on SiC Device in Traction Drive System

在大功率牵引变流器中,采用具有开关速度快、耐高温、开关损耗低等诸多优势的SiC器件替代Si器件,并构建基于SiC器件的三电平ANPC变换器,可以大大减轻变流器的散热系统负担,有助于实现牵引系统轻量化,提升变流器的功率密度和整体效率。对4种三电平ANPC变换器拓扑(2种SiC+Si的混合型三电平ANPC拓扑、全SiC型三电平ANPC拓扑和全Si型三电平ANPC拓扑)及适用于不同拓扑结构的调制策略进行了详细的分析。结合4种拓扑工作于各自最优调制策略下的换流过程,对不同拓扑的功率损耗和热平衡特性等方面通过仿真验证进行了定量分析比较。结果表明,全SiC型三电平ANPC拓扑损耗分布最均衡,工作效率最高;2-SiC混合型三电平ANPC拓扑在保证性能的基础上成本更低,可以作为采用SiC器件的牵引变流器的一种较高性价比的选择。

In high-power traction converter,SiC devices with many advantages such as fast switching speed,high temperature resistance and low switching loss are used to replace Si devices. The three-level active neutral-pointclamped(3L-ANPC)converter based on SiC devices can reduce the burden of heat dissipation system of the converter,realize the lightweight of the traction system,and improve the power density and overall efficiency of the converter.Four three-level ANPC converter topologies,including two SiC+Si hybrid 3L-ANPC topologies,all SiC 3L-ANPC topologies,all Si 3L-ANPC topologies and modulation strategies applicable to different topologies,were analyzed in detail. Combining the commutation process of the four topologies working under their respective optimal modulation strategies,the power loss and thermal balance characteristics of the different topologies were quantitatively analyzed and compared by simulation. The results show that the full SiC 3L-ANPC topology has the most balanced loss distribution and the highest working efficiency,and the 2-SiC hybrid 3L-ANPC topology has lower cost on the basis of ensuring performance,so it is a cost-effective choice for traction converters using SiC devices.