This paper discusses three-phase topologies for modulated pole machines (MPMs). The authors introduce a new threephase topology, which takes advantage of mutual flux paths; this is analyzed using 3-D finite-element methods and compared to a three-phase topology using three single-phase units stacked axially. The results show that the new "combined-phase MPM" exhibits a greater torque density, while offering a reduction in the number of components. The results obtained from two prototypes are also presented to verify the concept; the results show that the "combined-phase" machine could provide both performance and constructional benefits over prior MPM topologies.Index Terms-AC machine, modulated pole, mutual flux path, permanent magnet machine, phase isolation, three phase, transverse flux, torque dense.

This paper discusses a method for reducing cogging torque and harmonic content of back EMF waveforms in modulated pole machines (MPMs). Tooth pitching is applied to a separate phase MPM in order to reduce the most prominent harmonics present in a three-phase MPM's cogging torque. Experimental results show that the application of tooth pitching to these machines can reduce the cogging torque and back EMF harmonics significantly. This comes without a significant impact to the useful output of the machine, which is confirmed by comparison of measured results for two prototypes. Such a technique can be easily applied to existing machine designs without the need for extra components and for the same production cost.

No abstract

This paper discusses a method for reducing cogging torque and harmonic content of back EMF waveforms in modulated pole machines (MPMs). Tooth pitching is applied to a separate phase MPM in order to reduce the most prominent harmonics present in a three-phase MPM's cogging torque. Experimental results show that the application of tooth pitching to these machines can reduce the cogging torque and back EMF harmonics significantly. This comes without a significant impact to the useful output of the machine, which is confirmed by comparison of measured results for two prototypes. Such a technique can be easily applied to existing machine designs without the need for extra components and for the same production cost.

The modulated pole machine (MPM) is known to offer high torque density utilizing permanent magnets and a three dimensional flux pattern. However, their construction requires a departure from conventional coil wound teeth formed of lamination stacks which can be a challenge. In this paper three construction techniques for MPM stators are compared: pure soft magnetic composite, pure lamination and a hybrid of the two. Simulation and practical knowledge of the build of each of these machines, including torque capability and mechanical tolerances is presented and discussed. Using the methods proposed here, it is shown that the pure laminate MPM machine has the potential to offer the greatest torque per kg of active material, yet it is the hybrid machine which delivers the highest absolute torque.