A Rotor With Axially and Circumferentially Magnetized Permanent Magnets

In recent years, the drive to minimize or eliminate the use of rare-earth permanent magnets has been accelerated by the significant fluctuations in prices and the potential restrictions on future supply. Therefore, the paper presents a rotor equipped with axially and circumferentially magnetized permanent magnets, which can be employed for internal and external rotor machine topologies. It has been shown that when Sintered Ferrite is employed, airgap flux densities similar to those encountered in electrical machines employing rare-earth permanent magnets can be achieved. It has also been shown, that such flux densities can be achieved for relatively small ratios of active axial length to diameter of the rotor.