Community Research and Development Information Service - CORDIS

FP7

PECOAT — Result In Brief

Project ID: 307309
Funded under: FP7-JTI
Country: United Kingdom
Domain: Energy

New coatings for aircraft high-voltage systems

Electrical discharges in aircraft power electronics are a potential risk that can be mitigated by the careful design of the electrical systems. Innovative circuit board coatings capable of withstanding the extreme temperature and pressure conditions experienced by aircraft can provide this protection.
New coatings for aircraft high-voltage systems
The Aerospace Information Report (AIR) 'High Voltage Design Guidelines for Aerospace Systems' developed by SAE International provides a framework for designing high-voltage subsystems for use in more-electric aircraft. The AIR identifies design risks, mitigation techniques and testing methods for more-electric aircraft.

High-voltage systems on board are prone to electrical discharges, which can be exacerbated by low pressures, humidity and variable temperatures. Electrical discharges include disruptive, partial and tracking discharges, which beyond a certain threshold increase the likelihood of an electrical discharge event that can lead to significant failures in high-voltage power electronics.

Within the EU-funded project PECOAT (Novel coating systems for power electronics in aerospace environments), researchers worked to develop new coatings for power electronics that can withstand extreme conditions in harsh environments. The focus was on electronics subject to an open-box environment, meaning that pressure and temperature vary depending on altitude.

Researchers examined polymers such as polyurethane, acrylic, parylene and silicone. Test results showed that thermal cycling, thermal ageing and humidity had a minor influence on the breakdown voltages relative to samples that were not subject to the ageing process. Partial discharge was found to have stronger impact on the surface of coatings, causing substantial ageing and degradation.

Key design decisions to minimise the risk of electrical discharge also include careful spacing of components and control of the manufacturing process. PECOAT provided recommendations to industrial partners on board design and it fabricated new boards with reduced track spacings. The new design guidelines on track spacings on printed circuit boards and revised coating techniques should allow industrial partners to modify production processes and produce circuit boards of reduced size and free of partial discharge at higher voltages.

Use of the newly developed coatings will allow power electronics systems to operate with increased power density. By removing the hitherto-used hermetically sealed enclosures for the protection of power electronics, they will also enable reductions in aircraft weight.

Related information

Keywords

Coatings, aircraft, high-voltage systems, electrical discharges, power electronics, PECOAT
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