Cooling systems for future motor technologies in electric aircrafts

Electric aircraft propulsion promises to reduce the environmental impacts of flight, however in order for these to viable, significant improvements are needed in the associated technology. This project will focus primarily on the investigation of advanced cooling technologies which will enable the use of new and innovative motor technologies being developed by Toshiba.

High-speed electrical machines are one of the primary focuses in the evolution of electrical machine applications of electric vehicles, due to the high power density characteristics they can enable, but with this comes higher loss densities in the machines, resulting in an increase in temperature and a loss of efficiency. This brings about a very important challenge associated with the thermal management of the machine - with an increase in temperature, the requirement for more heat to be removed from the mechanical system is increased.


This project will perform a thorough investigation into the current methods of cooling which currently exist, and will endeavour to assess the performance, capability and viability of these already existing methods in conjunction with these new and innovative motor technologies, in which Toshiba are in the process of designing and developing for potential further use in aerospace propulsion applications. As well as an analysis of these current cooling technologies, the scope of this project will dig deeper into the use of more unconventional methods, which are being developed by scientists and engineers across the globe. Again, these methods will be assessed in terms of their potential for use alongside these new designs of motors being developed, with their performance, capability and viability scrutinised and their effectiveness compared with conventional methods.

There are a multitude of avenues for research into the field of cooling for electric machines, with the topologies and cooling techniques fairly well defined for these conventional methods - primarily involving air cooling, water cooling and oil cooling, these different types of conventional cooling can be further broken down into more specific topologies and methods. As previously mentioned, there are unconventional, newer concepts of cooling technologies where there is a wide range of potential avenues for research which has previously been unexplored. Some examples of these new concepts are as following: Superconductor windings and their associated cooling methods, the use of heat pipes in an electric machine, phase change cooling and many others. Within this project there is the scope for research into a number of fundamental areas of these cooling technologies, including but not limited to: material selection and their performance, manufacturing of the cooling system components and materials and the mechanical design of the cooling systems. There are lots of methods to be used to analyse these cooling systems and their effectiveness, using a variety of numerical modelling and experimental methods, with the potential for the use of highly complex computational software such as 'computational fluid dynamics'.

At this stage of the project, it is not yet fully defined which avenue of electric machine cooling technologies will be the primary focus, however there are a significant number of potential routes to be investigated, with lots of potential for theoretical and experimental research. With many of these technologies not yet fully understood, research into some of these areas would be massively advantageous for the push to fully electric aircraft in the near future.

This CDT will produce power electronics specialists with industrial experience, and will equip them with key skills that are essential to meet the future power electronics challenges. They will be highly employable due to their training being embedded in industrial challenges with the potential to become future leaders through parallel entrepreneurial and business acumen training. As such, they will drive the UK forward in electric propulsion development and manufacturing. They will become ambassadors for cross-disciplinary thinking in electric propulsion and mentors to their colleagues. With its strong industrial partnership, this CDT is ideally placed to produce high impact research papers, patents and spin-outs, with support from the University's dedicated business development teams. All of this will contribute to the 10% year upon year growth of the power electronics sector in the UK, creating more jobs and added value to the UK economy.

Alongside the clear benefits to the economy this CDT will sustain and enhance the UK as a hub of expertise in this rapidly increasing area. UK R&D is set to shift dramatically to electrical technologies due to, amongst other reasons, the target to ban petrol/ diesel propulsion by 2040. Whilst the increase in R&D is welcome this target will be unsustainable without the right people to support the development of alternative technologies. This CDT will directly answer this skills shortage enabling the UK to not only meet these targets but lead the way internationally in the propulsion revolution.

Industry and policy stakeholders will benefit through-
a) Providing challenges for the students to work through

b) Knowledge exchange with the students and the academics

c) New lines of investigation/ revenue/ process improvement

d) Two way access to skills/ equipment and training

e) A skilled, challenge focused workforce


Society will benefit through-
a) Propulsion systems that are more efficient and require therefore less energy reducing cost of travel

b) Engineers with new skillsets working more cost-effective and more productive

c) Skilled workforce who are mindful considering the environmental and ethical impact

d) Graduates that understand equality, diversity and inclusion


Environment will benefit through-
a) Emission free cars powered by clean renewable energy increasing air quality and reducing global warming

b) Highly efficient planes reducing the amount of oil and therefore oil explorations in ecological sensitive areas such as the arctic can be slowed down, allowing sufficient time for the development of new alternative environmental friendly fuels.

c) Significant noise reduction leading to quiet cities and airports