Axial flux concentration technique applied to the design of permanent magnet motors: theoretical aspects and their numerical and experimental validation

Permanent magnet motors are widely used in drive technology. The use of ferrite magnets in this type of machine is attractive due to their low cost, but its performance is usually poor due to the low flux density in the airgap. A new topology for the magnetic circuit is proposed, which uses the concept of axial flux concentration. It enables a substantial increase in the flux per pole, even with ferrite magnets, thereby improving motor performance at a low cost. It is shown that the effect is equivalent to using a fictitious magnet material, with augmented remanence and recoil permeability. The proposed topology is applied in a prototype synchronous motor. The improvement in its performance is confirmed by both experimental procedure and finite element modeling in three dimensions