Effects of Frequency and Temperature on Electric Field Mitigation Method via Protruding Substrate Combined with Applying Nonlinear FDC Layer in Wide Bandgap Power Modules
Effects of Frequency and Temperature on Electric Field Mitigation Method via Protruding Substrate Combined with Applying Nonlinear FDC Layer in Wide Bandgap Power Modules
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DOI：
10.3390/en13082022
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发表时间：
2020-04
期刊：
影响因子：
3.2
通讯作者：
Maryam Mesgarpour Tousi;M. Ghassemi
中科院分区：
文献类型：
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作者：
Maryam Mesgarpour Tousi;M. Ghassemi
我们之前的研究表明，包括（1）金属层偏移，（2）堆叠衬底设计和（3）突出衬底的几何技术，无论是单独还是组合，都不能解决高压高密度宽带隙（WBG）功率模块中的高电场问题。然后，第一次，我们表明，上述几何方法的组合和非线性场依赖电导率（FDC）层的应用可以解决这个问题。根据IEC 61287-1，在50 Hz正弦交流电压下进行模拟。然而，在实践中，设想的WBG功率模块的绝缘材料将处于频率高达几十kHz且温度高达几百度的方波电压脉冲下。氮化铝（AlN）陶瓷，硅凝胶，和非线性FDC材料的相对介电常数和电导率，在我们以前的研究中被假定为常数，可能是频率和温度依赖性，和它们的依赖性应考虑在模型中。这是在电力电子模块中处理电场计算的其他论文的情况，其中假设密封剂和陶瓷基板材料的介电常数和AC电导率在室温下并且对于50或60 Hz AC正弦电压。因此，仍然没有答案的大问题是电场模拟是否适用于高温和高频条件。在本文中，这一技术差距是解决的频率和温度相关的有限元法（FEM）模型的绝缘系统设想为6.5千伏高密度WBG功率模块将开发在COMSOL Multiphysics，其中一个突出的基板结合非线性FDC层的应用被认为是解决高场问题。利用该模型，研究了频率和温度对所提出的电场降低方法的有效性的影响。
Our previous studies showed that geometrical techniques including (1) metal layer offset, (2) stacked substrate design and (3) protruding substrate, either individually or combined, cannot solve high electric field issues in high voltage high-density wide bandgap (WBG) power modules. Then, for the first time, we showed that a combination of the aforementioned geometrical methods and the application of a nonlinear field-dependent conductivity (FDC) layer could address the issue. Simulations were done under a 50 Hz sinusoidal AC voltage per IEC 61287-1. However, in practice, the insulation materials of the envisaged WBG power modules will be under square wave voltage pulses with a frequency of up to a few tens of kHz and temperatures up to a few hundred degrees. The relative permittivity and electrical conductivity of aluminum nitride (AlN) ceramic, silicone gel, and nonlinear FDC materials that were assumed to be constant in our previous studies, may be frequency- and temperature-dependent, and their dependency should be considered in the model. This is the case for other papers dealing with electric field calculation within power electronics modules, where the permittivity and AC electrical conductivity of the encapsulant and ceramic substrate materials are assumed at room temperature and for a 50 or 60 Hz AC sinusoidal voltage. Thus, the big question that remains unanswered is whether or not electric field simulations are valid for high temperature and high-frequency conditions. In this paper, this technical gap is addressed where a frequency- and temperature-dependent finite element method (FEM) model of the insulation system envisaged for a 6.5 kV high-density WBG power module will be developed in COMSOL Multiphysics, where a protruding substrate combined with the application of a nonlinear FDC layer is considered to address the high field issue. By using this model, the influence of frequency and temperature on the effectiveness of the proposed electric field reduction method is studied.