An original in-situ way to build field grading materials (FGM) with permittivity gradient using electrophoresis

This paper reports on an original method developed at LAPLACE to structure field grading materials (FGM) by local handling of high permittivity ceramic (SrTiO $_{\mathbf {3}}$) particles in an epoxy resin using electrophoresis (i.e., DC voltage application). This new way of structuring composites allows building FGM with a high permittivity region (region with high particle concentration) while the rest of the composite remains with lower permittivity (region with low particle concentration). The resin curing enables to‘freeze’ the particles with this spatial arrangement. Process details and dielectric characterization of each region of the FGM composites are reported. Finally, a clear demonstration of the FGM performances, used as a field grading encapsulation material for high voltage power electronics modules, is shown supported both by field repartition simulation and experimental breakdown voltage improvements of encapsulated direct bonded copper (DBC) substrates.

[1]  Masahiro Sato,et al.  Dynamic potential distributions of surface discharge in silicone gel , 2015, IEEE Transactions on Dielectrics and Electrical Insulation.

[2]  J. Schuderer,et al.  Nonlinear resistive electric field control for power electronic modules , 2012, IEEE Transactions on Dielectrics and Electrical Insulation.

[3]  D. Newcombe,et al.  Partial discharge control in a power electronic module using high permittivity non-linear dielectrics , 2010, IEEE Transactions on Dielectrics and Electrical Insulation.

[4]  O. Lesaint,et al.  Streamers and partial discharge mechanisms in silicone gel under impulse and AC voltages , 2008, IEEE Transactions on Dielectrics and Electrical Insulation.

[5]  H. Okubo,et al.  Application of functionally graded material for solid insulator in gaseous insulation system , 2006, IEEE Transactions on Dielectrics and Electrical Insulation.

[6]  S. Hartmann,et al.  Analysis of insulation failure modes in high power IGBT modules , 2005, Fourtieth IAS Annual Meeting. Conference Record of the 2005 Industry Applications Conference, 2005..

[7]  G. Mitic,et al.  IGBT module technology with high partial discharge resistance , 2001, Conference Record of the 2001 IEEE Industry Applications Conference. 36th IAS Annual Meeting (Cat. No.01CH37248).

[8]  G. Lefranc,et al.  Localisation of electrical-insulation- and partial-discharge failures of IGBT modules , 1999, Conference Record of the 1999 IEEE Industry Applications Conference. Thirty-Forth IAS Annual Meeting (Cat. No.99CH36370).