轨道交通牵引四象限变流器三电平SiC/Si混合型拓扑损耗分析

Power Loss Analysis of Three-level SiC/Si Hybrid Topology of Traction Four-quadrant Converter in Railway Transportation

三电平SiC/Si混合型拓扑能满足低功率损耗的需求,其成本又低于全SiC拓扑,已逐渐应用于各类电力电子装置。由于轨道交通牵引四象限变流器应用场合的开关频率不高,而功率较大,不同的三电平SiC/Si混合型拓扑在损耗和效率上的优劣有待进一步评估。为此,提出一种T型中点箝位三电平SiC/Si混合型拓扑(TNPC-H2),在建立的损耗模型的基础上,推导了其与已有的有源中点箝位三电平SiC/Si混合型拓扑(ANPC-H1)的损耗计算公式,并将2种混合拓扑的成本、损耗和效率进行了理论计算的分析和对比。结果表明TNPC-H2更适用于低频场合,而ANPC-H1适用范围广,且开关频率越高其优势越突出。

The three-level SiC/Si hybrid topology has been gradually applied to various power electronics devices owing to its low power loss and lower cost compared with the full SiC topology.Since the switching frequency of a traction four-quadrant converter in railway transportation under the application scenarios is not high and its output power is relatively larger,the performances of different three-level SiC/Si hybrid topologies need to be further evaluated in terms of loss and efficiency.In this paper,a T-type neutral point clamped three-level SiC/Si hybrid topology(TNPC-H2)is proposed.On the basis of the establishment of a loss model,the power loss calculation formulas for TNPC-H2 and the existing active neutral point clamped three-level SiC/Si hybrid topology(ANPC-H1)are derived.Moreover,their costs,power losses and efficiencies are theoretically calculated and compared.Results show that TNPC-H2 is more suitable for application scenarios with low switching frequency.In comparison,ANPC-H1 has a wide range of applicability,and the higher the switching frequency,the more obvious its advantage.