Laminated busbar PDIV improvement using a new varnish-based insulation technology with micro/nano fillers

Abstract

Laminated Busbars (LBB) have proved to be the best solution for the design of power electronic devices operating at high power due to their low parasitic inductance and high current capabilities. As power electronic devices are becoming subjected to more and more severe operating conditions (due to electrification of aircrafts and SiC semiconductors development), innovative insulation solutions are needed to deal with Partial Discharges (PD) appearance in harsh conditions, like low pressure and high temperature. This paper presents a new varnish-based insulation technology as a low cost and more environmentally friendly solution for LBB insulation. Additionally, a theoretical study using electrostatic simulations backed with practical tests show different ways in which Partial Discharges Inception Voltage (PDIV) of a LBB sample can be improved using similar technologies like the addition of a certain quantity of varnish in critical areas. Furthermore, an investigation of further performance improvements using micro-nano fillers is presented. Such fillers include Alumina, Silica and hexagonal Boron Nitride. Improvements include high temperature resistance (up to 200°C), higher creepage distances and higher thermal conductivity.