El repte/The challenge

Since 2011, the abrupt increase of the raw material costs in rare earth permanent magnets has shifted interest in the field of electrical machines towards new topologies with a lower volume of permanent magnets, and even without those. This circumstance has renewed the interest for switched reluctance machines, especially in the field of electric traction. SRM present some advantages, such as simple and robust construction and torque-speed characteristics that match very well with the needs of electric traction.

However, conventional radial SRM drives have drawbacks as, for example, lower performance than permanent magnet synchronous motors or brushless D.C. motors, high torque ripple and acoustic noise.

Some studies carried out in axial flux switched reluctance motors; demonstrate that with this type of machine is possible to obtain higher torque density than in conventional radial flux switched reluctance machines.