Epoxy resin is widely used in the support,insulation,and packaging components of electrical equipment owing to their excellent insulation,thermal,and mechanical properties.However,epoxy-resin insulation often suffers ...Epoxy resin is widely used in the support,insulation,and packaging components of electrical equipment owing to their excellent insulation,thermal,and mechanical properties.However,epoxy-resin insulation often suffers from thermal and mechanical stresses under extreme environmental conditions and a compact design,which can induce electrical tree degradation and insulation failure in electrical equipment.In this study,the photoelastic method is employed to investigate the thermal-mechanical coupling stress dependence of the electrical treeing behavior of epoxy resin.Typical electrical tree growth morphology and stress distribution were observed using the photoelastic method.The correlation between the tree length and overall accumulated damage with an increase in mechanical stress is determined.The results show that compressive stress retards the growth of electrical trees along the electric field,while tensile stress has accelerating effects.This proves that the presence of thermal stress can induce more severe accumulated damage.展开更多
Electrical stress experiments under different bias configurations for AlGaN/GaN high electron mobility transistors were performed and analyzed.The electric field applied was found to be the extrinsic cause for the dev...Electrical stress experiments under different bias configurations for AlGaN/GaN high electron mobility transistors were performed and analyzed.The electric field applied was found to be the extrinsic cause for the device instability,while the traps were recognized as the main intrinsic factor.The effect of the traps on the device degradation was identified by recovery experiments and pulsed I-V measurements.The total degradation of the devices consists of two parts：recoverable degradation and unrecoverable degradation.The electric field induced traps combined with the inherent ones in the device bulk are mainly responsible for the recoverable degradation.展开更多
基金Supported by the National Natural Science Foundation of China(52377153)and Science and Technology Project of Hebei Education Department(QN2023073).
文摘Epoxy resin is widely used in the support,insulation,and packaging components of electrical equipment owing to their excellent insulation,thermal,and mechanical properties.However,epoxy-resin insulation often suffers from thermal and mechanical stresses under extreme environmental conditions and a compact design,which can induce electrical tree degradation and insulation failure in electrical equipment.In this study,the photoelastic method is employed to investigate the thermal-mechanical coupling stress dependence of the electrical treeing behavior of epoxy resin.Typical electrical tree growth morphology and stress distribution were observed using the photoelastic method.The correlation between the tree length and overall accumulated damage with an increase in mechanical stress is determined.The results show that compressive stress retards the growth of electrical trees along the electric field,while tensile stress has accelerating effects.This proves that the presence of thermal stress can induce more severe accumulated damage.
基金Project supported by the National Natural Science Foundation of China(Nos.60890192,60876009)
文摘Electrical stress experiments under different bias configurations for AlGaN/GaN high electron mobility transistors were performed and analyzed.The electric field applied was found to be the extrinsic cause for the device instability,while the traps were recognized as the main intrinsic factor.The effect of the traps on the device degradation was identified by recovery experiments and pulsed I-V measurements.The total degradation of the devices consists of two parts：recoverable degradation and unrecoverable degradation.The electric field induced traps combined with the inherent ones in the device bulk are mainly responsible for the recoverable degradation.
