A Comprehensive Review of Mitigation Strategies to Address Insulation Challenges Within High-Voltage, High-Power-Density (U)WBG Power Module Packages

Abstract

Within the expanding domain of electrical power demand, the future of power module packaging is entwined with the progress of (ultra) wide bandgap [(U)WBG] materials. These materials, such as silicon carbide (SiC), aluminum nitride (AlN), and diamond, offer advantages with higher power density, decreased weight, and expanded operational abilities regarding temperature, voltage, and frequency. However, the pursuit of pushing these limits confronts challenges within insulation systems, which may struggle to endure the demands of these parameters, potentially resulting in unfavorable conditions such as high electric field, space charge accumulation, electrical treeing, and partial discharge (PD), leading to insulation failure. The emphasis of this article is to review the insulation challenges within (U)WBG power modules and recent research in mitigating the electric field stress at triple points (TPs) and resolving the PD issues. This article first discusses the high electric field stress issue at TPs. Then, ceramic substrate materials, encapsulation materials, and the influence of harsh weather conditions on them are reviewed. The space charge, electrical treeing, and PD issues within encapsulation materials are analyzed under practical operation conditions of (U)WBG power modules such as high frequency, temperature, and square wave pulses. Finally, the various strategies to alleviate the associated insulation challenges are meticulously discussed. While the identified mitigation strategies are able to strengthen insulation systems for packaging, their validation under actual operational conditions of (U)WBG power modules remains relatively unexplored, representing a potential avenue for further investigation. This review offers a valuable framework by providing the constraints of the current studies and recommendations for the future that can be utilized as a reference point for future research endeavors.