Process optimization for heterogeneous capacitive grading materials by voltage and time monitoring

Transportation electrification is trending as one of the main solutions that allow the reduction of greenhouse gases levels in the air and slow down the climate change, especially for aerospace field. One of the ways that can allow reaching this goal for electrified systems is the voltage increase and reduce the volume of system onboard. This approach induces consequently very high electrical constraints on the insulating materials used in the power conversion systems. These local high electric fields can cause premature failure, by partial discharge activity and insulation breakdown. In order to efficiently reduce the electrical stresses, the design of new system of stress-control encapsulation seems be promising as it does not affect the volume of the power module and has a negligible impact on the overall mass. An approach based on the use of low filler ratio composites and the monitoring of the particles (SrTiO
3
, BaTiO
3
) density by the electric potential to tailor around critical areas where the electric field is high has been validated on simple configuration between two adjacent electrodes. In addition, this approach has been used successfully to apply the FGM on various substrate electrodes of a power module by using a removable electrode in front of the substrate. In this paper, the impact of the applied electric potential and its duration will be presented in order to evaluate and optimize the process to allow applying electrodeposition with a homogenous thickness of stress-control layer.