Abstract
Many sectors, such as transportation systems, are undergoing rapid electrification due to the need for the mitigation of CO2 emissions. To ensure safe and reliable operation, the electrical equipment must be able to work under various environmental conditions. At high altitudes, the low pressure can adversely affect the health of insulating materials of electrical systems in electric aircraft. A well-known, primary aging mechanism in dielectrics is partial discharge (PD). This study targets internal PD evaluation in an insulated-gate bipolar transistor (IGBT) module under low-pressure conditions. The estimation of electric field distribution is conducted through 3D finite element analysis (FEA) using COMSOL Multiphysics®. The procedure of PD detection and transient modeling is performed in MATLAB for two pressure levels (atmospheric and half-atmospheric). The case study is the IGBT module with a void or two voids in the proximity of triple joints. The single-void case demonstrates that at half-atmospheric pressure, the intensity of discharges per voltage cycle increases by more than 40% compared to atmospheric pressure. The double-void case further shows that a void that is harmless at sea level can turn into an additional source of aging and couple with the other voids to escalate PD intensity by a factor of two or more.
Highlights
The single-void case demonstrates that at half-atmospheric pressure, the intensity of discharges per voltage cycle increases by more than 40% compared to atmospheric pressure
The double-void case further shows that a void that is harmless at sea level can turn into an additional source of aging and couple with the other voids to escalate partial discharge (PD) intensity by a factor of two or more
The cross-section of the insulated-gate bipolar transistor (IGBT) module immersed in silicone gel is demonstrated in
Summary
Partial discharge is a stochastic, multi-physical phenomenon, and its analysis rePartial discharge isofa programming stochastic, multi-physical phenomenon, analysis requires quires a combination and physical modeling ofand theitstest configuration. The this model was unable to with the valid void, physical and the rest of the dielectric This model was unable to provide provide insights into the PD mechanism. In thetoinduced model,state the authors used the notion in of the induced charge on the electrode describecharge the transient of the partial discharge void [28,29,30]. While electrode to describe the transient state of the partial discharge in the void [28,29,30] While this model could provide a more accurate presentation of physics behind PDs, it cannot this model could provide a more accurate geometries presentationand of physics behind. The presence of unwanted voids with a lower dielectric constant compared to the surrounding dielectric causes the aging mechanism.
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