SiC MOSFET与SiC SBD换流单元瞬态模型

Analytical Transient Model of Commutation Units with SiC MOSFET and SiC SBD Pair

相较于硅(Si)器件,碳化硅(SiC)器件所具有的高开关速度与低通态电阻特性增加了其瞬态波形的非理想特性与对杂散参数影响的敏感性,对其瞬态建模的精度提出更高的要求。通过功率开关器件瞬态过程的时间分段、机理解耦与参数解耦,突出器件开关特性,弱化物理机理,简化瞬态过程分析,建立基于SiC MOSFET与SiC SBD的换流单元瞬态模型。理论计算结果与实验结果对比表明,该模型能够较为精细地体现SiC MOSFET开关瞬态波形且能够较为准确地计算SiC MOSFET开关损耗。该模型参数可全部由数据手册提取,有较强的实用性。

Compared with Si devices, the higher switching speed capability and lower on-state resistance of Silicon Carbide （SiC） devices increase the non-ideality and sensitivity to parasitic parameters of their switching transients. Thus, more accurate analytical transient modeling is required. In this paper, switching transients of power switching devices are simplified by time slicing, mechanism decoupling and nonlinear parameter decoupling, in order to highlight switching characteristics of switching transients while simplifying the analysis of their physical mechanisms. An analytical transient model of a commutation unit with SiC MOSFET and SiC SBD pair is proposed. Analytical calculation and experiment waveforms are compared. The results show that the proposed model is able to provide a relatively accurate prediction of switching transient waveforms and switching losses of SiC MOSFET. All the parameters in the proposed model can be extracted from datasheets, which enhances its feasibility.