Abstract
Epoxy (EP) resins find widespread application in power electronic (PE) applications characterized by multifrequency electrical stresses. Transient thermal overloads are also not uncommon due to, for example, short circuits in the external circuit. This article investigates the influence of various temperatures on broadband dielectric properties of EP insulation, above and below the glass transition temperature (T g). The underlying multitimescale dynamic processes, conductivity, and relaxation mechanisms are revealed based on multiple spectroscopy techniques. In particular, the dependence on the frequency and amplitude of loss peaks on temperatures is modeled considering the potential use of this model in the multiphysics design of PE applications. Results show that the high temperature above T g substantially triggers noticeable low-frequency quasi-dc conductance behavior and multiple non-Debye relaxation processes in higher-frequency regions. Once the operating temperature exceeds the T g, the low-frequency (0.1-100 Hz), real permittivity and loss factor will increase by more than dozens of times. The low-frequency quasi-dc conductivity will increase by about six magnitudes from 25°C to 200°C. As a result of the findings in this article, future insulation circuit modeling and reliable insulation design will consider the underlying multitimescale physical mechanisms to support the multifrequency applications.
Original language | English |
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Journal | IEEE Transactions on Dielectrics and Electrical Insulation |
Volume | 31 |
Issue number | 5 |
Pages (from-to) | 2290-2298 |
Number of pages | 9 |
DOIs | |
Publication status | Published - 2024 |
Keywords
- Broadband Dielectric Properties
- Conductivity
- Dielectrics
- Epoxy Resin
- Glass
- Glass Transition Temperature
- High Temperature
- Insulation
- Permittivity
- Power Electronics Applications
- Power Electronics Applicatiosn
- Temperature
- Temperature measurement
- power electronics (PEs) applications
- Broadband dielectric properties
- glass transition temperature
- high temperature
- epoxy (EP) resin