PhD in Engineering: Voltage uprating for more-electric and hybrid aircraft

    Cardiff University
    First Stage Researcher (R1)
    31/05/2018 12:00 - Europe/London
    United Kingdom › Cardiff

This research project proposes to quantify the effect of atmospheric conditions on the partial discharge thresholds on the more and all-electric aircraft.

Decarbonisation of the transport sector is a major priority, both nationally and globally. It is estimated that the domestic and international aviation sectors constitute 2% of the global CO2 emissions arising from human activity. The member states of the UN International Civil Aviation Organisation are committed to offset any increases in emissions beyond 2020 which, combined with the drive for increasing fuel efficiency, will stimulate aircraft weight reduction beyond that already achieved through the adoption of composite airframe materials.

The more-electric aircraft concept permits higher system efficiencies to be realised through electrification of traditional mechanical and hydraulic aircraft subsystems. It can also be considered a stepping stone to realising a commercial hybrid and all-electric aircraft.

Both types of aircraft will be equipped with more diverse and safety-critical subsystems, based on high density power electronic converters and system ratings in excess of 1000 Volts. The increased stress experienced by cable insulation, connectors and other equipment, combined with extreme and dynamic environmental conditions experienced in flight, presents a number of technical challenges.

The uprating of electrical power systems requires the aircraft design engineer to control for electrostatic phenomena which will arise within the normal operating regime of the aircraft, and there are a number of factors that must be taken into account when assessing the performance of such systems:

  • The increased use of switched dc and its influence on insulation stress.
  • The increase in the system voltage, and the frequency and severity of temporary over-voltages.
  • Changes in altitude and atmospheric conditions (temperature, pressure and humidity)
  • Indirect effects induced by lightning strikes.

There is to date very little published work concerned with dynamic atmospheric effects on ascent and descent, or the implications of short term system- and atmospherically-induced over voltages. A fundamental understanding of these parameters in medium-voltage dc systems is critical to the increasing electrification of airborne power distribution, and places renewed emphasis on insulation coordination and the mitigation of partial discharges.

The following unknowns have been identified as limitations of the scientific understanding in the up-rating of airborne electrical systems:

  • Validity of the Paschen for specifying minimum conductor segregation.
  • Validity of steady-state atmospheric correction factors.
  • Dependence of partial discharge inception on the applied voltage wave shape.

A purpose-built test facility will be established to replicate the dynamic atmospheric conditions to which aircraft systems are subjected in service. Simulations will be performed to determine the appropriate test conditions, which will then be applied to standard test samples to study the mechanisms and thresholds of partial discharge activity. The findings will be used to inform a set of correction factors that system designers may use in the robust design of future airborne electrical systems.


Doctoral stipend matching UK Research Council National Minimum

Eligibility criteria

Candidates should hold or expect to gain at least a 2.1 degree or a Master’s level qualification (or their equivalent) in a relevant subject. Applicants whose first language is not English will be required to demonstrate proficiency in the English language (IELTS 6.5 or equivalent).

Selection process

Consideration is automatic upon application for admission to the Doctor of Philosophy in Engineering.

In the "Research proposal and Funding" section of your application, please specify the project title and supervisors of this project and copy the project description in the text box provided.

Please select “No, I am not self-funding my research” when asked whether you are self-funding your research.

Please add 'PhD in Engineering: Voltage uprating for more-electric and hybrid aircraft' when asked "Please provide the name of the funding you are applying for".

Additonally, interested applicants are invited to send a CV and covering email/letter to engineering-pgr@cardiff.ac.uk.

Offer Requirements


Candidates should hold or expect to gain at least a 2.1 degree or a Master’s level qualification (or their equivalent) in a relevant subject. Applicants whose first language is not English will be required to demonstrate proficiency in the English language (IELTS 6.5 or equivalent)

Specific Requirements

The studentship is open to Home, EU and Overseas candidates. However, it should be noted that overseas candidates will be required to pay the difference between the home and overseas fee.

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Cardiff University
United Kingdom

EURAXESS offer ID: 286313