Analysis of SiC MOSFETs under hard and soft-switching
Analysis of SiC MOSFETs under hard and soft-switching
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DOI：
10.1109/ecce.2015.7309974
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发表时间：
2015-09
期刊：
影响因子：
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通讯作者：
M. Ahmed;R. Todd;A. Forsyth
中科院分区：
文献类型：
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作者：
M. Ahmed;R. Todd;A. Forsyth
本文介绍了硬开关和软开关碳化硅MOSFET的分析模型及其实验验证。这些模型包括电路中的高频寄生元件，仅使用数据表参数即可非常快速、准确地模拟SiCMOSFET的开关行为。与硅器件相比，碳化硅器件的开关速度要高得多，这就需要对其进行清晰而详细的分析。每个开关暂态被划分为四个不同的子周期，并求解它们各自的等效电路以逼近电路状态变量。该模型考虑了碳化硅器件结电容的非线性。解析建模结果与LTspice仿真结果接近，仿真时间缩短了三倍。分析了吸收电容对软开关波形的影响，并进行了实验验证，从而使分析模型能够用于评估未来的软开关解决方案。研究发现，缓冲支路除了可以降低开关损耗外，还可以显著降低SiCMOSFET的关断振铃。
Analytical models for hard-switching and soft-switching SiC MOSFETs and their experimental validation are described in this paper. The models include the high frequency parasitic components in the circuit and enable very fast, accurate simulation of the switching behaviour of SiC MOSFET using only datasheet parameters. The much higher switching speed of SiC devices over Si counterparts necessitates a clear detailed analysis. Each switching transient was divided into four distinct sub-periods and their respective equivalent circuits were solved to approximate the circuit state variables. Nonlinearities in the junction capacitances of SiC devices were considered in the model. Analytical modelling results were close to the LTspice simulation results with a threefold reduction in the simulation time. The effect of snubber capacitors on the soft-switching waveforms is also explained analytically and validated experimentally, which enables the analytical model to be used to evaluate future soft-switching solutions. It was found that the snubber branch can significantly reduce the turn off ringing of the SiC MOSFET in addition to the reduction of switching losses.