Space charge problems have been widely acknowledged for solid insulation such as polyethylene for high-voltage dc cable insulation. However, the effect of space charge on the reliability of high-voltage power module packaging insulation has not been systematically investigated. In this article, a simultaneous measurement of space-charge and isothermal relaxation current (IRC) is performed on silicone packaging insulation. An iterative algorithm based on the nonnegative least-square method is introduced to estimate multilevel trap energy distribution in silicone insulation. It is found that homocharges are accumulated around the electrodes, and more charges are accumulated with the increase in applied electric field and temperature. The local electrical field is distorted, and the threshold of the external applied electric field for charge accumulation decreases with increasing temperature. The trapped charges tend to be trapped in deep traps as the temperature increases. Furthermore, to investigate the charge dynamics in the complex power module package structure, a 2-D space-charge simulation model based on the combination of the bipolar charge transport model and finite-element method (FEM) is proposed with the parameters derived from the simultaneous measurement. According to the simulation results, the maximum electric field is located at the triple-junction position of the high-voltage power module package. With the accumulation of homocharges and the increase in temperature, the electric field decreases at the triple-point position but increases between the injected positive and negative charges. Space-charge behavior affects the local electric field of power module packaging insulation and should be thoroughly investigated in the future.

中文翻译：

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高压电源模块封装绝缘中的空间电荷和陷阱：同时测量和二维仿真


固体绝缘体（例如用于高压直流电缆绝缘体的聚乙烯）的空间电荷问题已得到广泛认可。然而，空间电荷对高压功率模块封装绝缘可靠性的影响尚未得到系统研究。在本文中，对有机硅封装绝缘材料进行了空间电荷和等温弛豫电流 (IRC) 的同步测量。引入基于非负最小二乘法的迭代算法来估计硅绝缘材料中的多级陷阱能量分布。研究发现，电极周围聚集了同质电荷，并且随着施加电场和温度的增加，聚集的电荷增多。局部电场发生畸变，电荷积累的外加电场阈值随着温度的升高而降低。随着温度升高，被捕获的电荷往往被捕获在深陷阱中。此外，为了研究复杂功率模块封装结构中的电荷动力学，提出了一种基于双极电荷传输模型和有限元方法（FEM）相结合的二维空间电荷仿真模型，其参数来自于同时测量。根据仿真结果，最大电场位于高压功率模块封装的三结位置。随着同质电荷的积累和温度的升高，电场在三相点位置减小，但在注入的正电荷和负电荷之间增大。空间电荷行为会影响功率模块封装绝缘的局部电场，未来应进行彻底研究。