Study of An Improved Yoke Permanent Magnet Motor With Booster Magnets Between Stator Modules

This paper aims to study a new stator permanent magnet (stator-PM) motor where the PMs are placed both in the yoke and between stator modules. From the standpoint of yoke- PM, the structure is similar to the biased-flux PM topology however, the torque density is increased. And, from the standpoint of the PM placement between stator modules, the proposed structure is similar to the stator-slot PM topology where the torque ripple is decreased and the power factor and efficiency is greatly enhanced. The core loss of this structure is suppressed compared to other structure. Moreover, because of this PM placement, an isolated path is provided to solely manage the temperature distribution of the magnets. Furthermore, a flux barrier is placed between stator poles in a way that the yoke magnet is prevented to be short-circuited. The armature winding is wounded around the flux barrier and like the flux- switching structure, the flux linkage in each coil can operate in the four operational regions. The operation principle and design procedure is explained and along with the electromagnetic performance, the demagnetization analyses of this structure are also conducted to better understand the superiority of the demagnetization withstanding of the proposed structure.