There are a wide variety of new electric machine designs being developed for use in battery electric vehicles (BEV) and hybrid electric vehicles. Different motor types are available such as brushless permanent magnet (BPM), induction, switched & synchronous reluctance and wound field synchronous machines. The BPM is available with radial or axial fields. The most popular motor type used in the current range of BEV and HEV is the radial airgap BPM motor with an interior permanent magnet (IPM) structure. The range of IPM topologies available to the designer is large with different numbers and position of the flux barriers and magnets. Nd-Fe-B is the predominant magnet type but is quite expensive due to the use of rare earth materials. There is some research into the use of cheaper ferrite magnets.
Various winding techniques are used such as distributed random wound and precision or bobbin tooth wound windings. There is also a current trend to use hairpin windings. Various cooling types are available such as the use of stator water jacket of various design, oil spray cooling of the end windings, passing oil through the windings, a rotational water jacket on the shaft, potted end windings, etc. New materials are also being developed to improve the magnetic and thermal properties of the machine design.
The workshop will include:
- Show the results of teardown studies on various existing machines from such vehicles as the Nissan LEAF, Tesla Model S, Toyota Prius, BPM i3, Honda Accord, etc.
- Demonstrate how reverse engineering benefits from electromagnetic and thermal simulation to gain a full understanding of a teardown motors performance.
- Show models developed in Motor-CAD predicting the performance of a range of existing BEV traction motors.
- Performance data calculated includes peak and continuous torque/speed envelopes, efficiency and loss maps, optimum field weakening angle maps and drive cycle analysis with predictions of motor temperature vs time.
- BPM, induction, switched & synchronous and wound field synchronous machine designs will be shown with a wide variety of cooling types, winding types and materials.
- Comparisons of model data with test data.
- Show initial results from some new research projects to develop BEV electric machines with higher performance and lower cost than existing state of the art machines.
Dr. Dave Staton did his PhD in computer aided design of electric motors at University of Sheffield in the mid 1980’s. Since then he has worked on electric motors, and in particular, the development of motor design software at Thorn EMI, the SPEED Laboratory at University of Glasgow and Control Techniques (part of Emerson Electric). Dave founded Motor Design Ltd. (MDL) in 1998 with a focus on development of software for electric motor design. MDL develop Motor-CAD software that integrates both electromagnetic and thermal analysis modules to simplify and speed up the design workflow.