Field Grading Composites Tailored by Electrophoresis—Part 3: Application to Power Electronics Modules Encapsulation

Abstract

A series of three articles presents an innovative way to build advanced functionally graded materials (FGM) based on polymer/ceramic (epoxy/SrTiO3) composites tailored by electrophoresis for field grading in power electronics. In this Part 3, this method is applied in the context of power modules for DBC substrate encapsulation. An evaluation of the FGM performances is reported based on electrostatic simulations and breakdown voltage measurements on encapsulated DBC substrates. The results show a significant mitigation of the electric fringe field at the triple point while breakdown is largely increased by a factor 2 for FGM composites compared to neat epoxy. The process enables to use the electric field reinforcements of HV electrical systems (e.g. tips coming from the design), and thus potential weak points, to locally 'self-heal' them in-situ. Such an electrophoresis process used to build FGM composites paves the way of the next generation of functionalized polymer composites used in high voltage power applications for improving the electrical aging of insulating materials and power system reliability.

Full-life-cycle eco-friendly polymeric insulating materials: research progress and future prospects

“…As figure 14 shows, its principle is similar to the bamboo in nature, bamboo timber obtains high mechanical strength through the non-uniform distribution of vascular bundle content. Unlike uniform structure, FGI has a non-uniform dielectric permittivity or conductivity distribution, which can be used to effectively homogenize the electric field of polymeric insulating through the optimized [83]. © [2021] IEEE.…”

“…© [2021] IEEE. Reprinted, with permission, from [83]. (b) ε-FGI insulator in gas insulated switchgears (GISs) and gas insulated transmission lines (GILs) (ε-FGI insulator used in 245 kV GIS and the flashover test results) [88].…”

Tailoring Electric Field Distortion in High-Voltage Power Modules Utilizing Epoxy Resin/Silicon Carbide Whisker Composites with Field-Dependent Conductivity

“…5 FGM with the centrifugation process is not suitable for application in the power module. Diaham et al 6 proposed an innovative electrophoresis method to develop FGM to construct a highpermittivity region near the triple point, reducing the high electric stress near the triple point and improving the breakdown strength of the power modules. Moreover, FDP materials cannot work under DC voltage.…”

A fabrication method for adaptive dielectric gradient insulating components

“…Research on dielectric gradient insulating components began in the 1970's, and the current preparation methods include lamination [9], centrifugation [10], flexible casting [11], electrophoresis [12], magnetophoresis [13], 3D printing [14], and magnetron sputtering [15]. From the perspective of controlling, the lamination, flexible casting, 3D printing, and magnetron sputtering methods are constructing dielectric gradients by artificial ‘Building block’, which cannot deal with the complex electric fields in space.…”