Electrical Insulation Weaknesses in Wide Bandgap Devices

Abstract

The power electronics research community is balancing on the edge of a game-changing technological innovation: as traditionally silicon (Si) based power semiconductors approach their material limitations, next-generation wide bandgap (WBG) power semiconductors are poised to overtake them. Promising WBG materials are silicon carbide (SiC), gallium nitride (GaN), diamond (C), gallium oxide (Ga 2 O 3 ) and aluminum nitride (AlN). They can operate at higher voltages, temperatures, and switching frequencies with greater efficiencies compared to existing Si, in power electronics. These characteristics can reduce energy consumption, which is critical for national economic, health, and security interests. However, increased voltage blocking capability and trend toward more compact packaging technology for high-power density WBG devices can enhance the local electric field that may become large enough to raise partial discharges (PDs) within the module. High activity of PDs damages the insulating silicone gel, lead to electrical insulation failure and reduce the reliability of the module. Among WBG devices, electrical insulation weaknesses in WBG-based Insulated Gate Bipolar Transistor (IGBT) have been more investigated. The chapter deals with (a) current standards for evaluation of the insulation systems of power electronics modules, (b) simulation and modeling of the electric field stress inside modules, (c) diagnostic tests on modules, and (d) PD control methods in modules.

High power density technologies for large generators and motors for marine applications with focus on electrical insulation challenges

“…Also, such failures in electrical components used in electric vehicles or aircraft that can impact the safety of the passengers are unacceptable. A critical review of the accelerated insulation aging issue under fast, repetitive voltage pulses, identifying technical gaps, and future research needs, has recently been carried out [51] and with a focus on power electronics modules in [52, 53].…”

Insulation Materials and Systems for Power Electronics Modules: A Review Identifying Challenges and Future Research Needs

“…This manuscript critically reviews recent efforts and presents technical gaps and challenges for developing insulation materials and systems for next-generation WBGbased devices for power electronics modules. A thorough and in-depth review of PD measurements, failure analyses, and control in high-power Si-IGBT modules has been done by the second author [6,7]. This paper discusses more recent research that was not reviewed in [6,7].…”

“…A thorough and in-depth review of PD measurements, failure analyses, and control in high-power Si-IGBT modules has been done by the second author [6,7]. This paper discusses more recent research that was not reviewed in [6,7]. Together, these three publications, [6,7] and this paper, cover almost all electrical insulation issues and challenges to power electronics modules.…”

Electric field enhancement control in active junction of IGBT power module

“…Meanwhile, there was a report that the application of functional materials on a highly stressed region is capable of reducing the effect of electric field. 12 The long-term experiment suggests that the presence of impurities in the proposed self-healing encapsulating liquid material may not make the materials to provide a complete reliable packaging system for the power electronic module since such impurity can be dragged to the high field region through the dielectrophoretic process. The numerical simulations, in this work, is to understand the failure risk of coated and uncoated IGBT related test object subjected to DC stress using finite element method (FEM) and then evaluate the operational reliability of chip diodes coated with polymer layer under varying relative humidity in comparison with other encapsulation materials.…”