Project challenges need for rare earth materials

09 July 2012

A new collaborative research programme led by Cobham Technical Services will investigate next-generation electric motors for high-end, low-carbon emission vehicles that do not require rare earth metals in their construction. The project, ‘Rapid Design and Development of a Switched Reluctance Traction Motor’, will also involve partners Jaguar Land Rover (JLR) and engineering consultant Ricardo UK. Les Hunt reports.

Cobham’s role is to develop multi-physics software and capture the other partners’ methodology in order to design, simulate and analyse the performance of high efficiency, lightweight electric traction motors that avoid the need for expensive magnetic materials. With these new software tools JLR and Ricardo will design and manufacture a prototype switched reluctance motor that addresses the particular requirements of luxury hybrid vehicles.

Aside from a desire to improve CO2 emissions reductions from hybrid vehicles by moving to more efficient and lower weight electric motors, there is now an urgent requirement to eliminate the use of rare earth elements, which are increasingly in short supply and consequently hugely expensive. Virtually all electric traction motors currently used in such applications employ permanent magnets made from materials such as neodymium-iron-boron and samarium-cobalt.

Since switched reluctance motors do not use permanent magnets, they are likely to provide the ideal replacement technology. However, one of the main challenges of the project will be to produce a torque-dense motor that is also quiet enough for use in luxury vehicles.

This latest project is one of 16 collaborative vehicle CO2 reduction R&D programmes to have won a total of £10m worth of funding from the TSB and the Department for Business, Innovation and Skills (BIS). The total value of the Cobham-led project is £1.5m, with half the amount funded by TSB/BIS, and the rest by the project partners.

According to Cobham Technical Services director, Kevin Ward, design software for switched reluctance motors is at about the same level as diesel engine design software when it was first introduced. Mr Ward’s team hopes to provide the consortium with enhanced design, FEA and analysis tools based on Cobham Vector Fields Software’s Opera suite. Cobham will also investigate advanced integration with its other multi-physics software applications to obtain more accurate evaluation of model related performance parameters such as vibration.

JLR’s head of research, Tony Harper says it is important to understand the capability of switched reluctance motors in the context of the vehicle as a whole so that component targets can be set to deliver the overall vehicle experience. Meanwhile, Ricardo UK chief engineer (innovation), Andrew Atkins, sees the development of technologies enabling the design of electric vehicle motors that avoid the use of expensive and potentially carbon-intensive rare-earth metals, as a major focus for the auto industry.

The project has a three year timetable, at the end of which improved design tools and processes will be in place to support rapid design, helping to accelerate the uptake of this technology on into production.

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