Performance Improvement of Dual Stator Axial Flux Spoke Type Permanent Magnet Vernier Machine

Abstract

This paper presents performance improvement of dual stator axial-flux spoke type permanent magnet vernier machine (DSAFST-PMVM), which has the capability to generate high torque at a lower speed due to magnetic gearing effect. Flux focusing effect is created by means of dual stator single rotor topology with spoke type permanent magnets. It is best suitable for high-performance industrial applications such as servo motors, robot arms, wind power, electric vehicles, and elevator applications. A PM shape is proposed in this paper which has notches in such a way that it produces discrete skew effect which reduces the cogging torque and torque ripples. Optimization of magnet shape is done to make the optimized model more competitive than the proposed and basic models. Main parameters such as back emf, cogging torque, torque ripples, electromagnetic torque, VTHD, airgap flux densities, flux density distribution, power factor, and power of the machine are compared among the basic model, proposed model, and optimized models. The comparative analysis is done by using the time stepped 3D finite element method.INDEX TERMS Axial flux, cogging torque, dual stator axial flux machine, flux focusing effect, magnetic gearing effect, torque ripples, vernier machine, finite element method.

Novel Differential Evolutionary Optimization Approach for an Integrated Motor-Magnetic Gear Used for Propulsion Systems

“…For each piece, belloging to a certain material (air, steel, PM), a specific mangetic reluctance is calculated, and next the magnetic flux is obtained. Thus, by multiplying the magnetomotive force of the PMs (dependend on the rotor position angle θ) of the outer rotor with the modulated flux of the inner part of the MG (the inner rotor and the static teeth part), one can obtain the output torque of the MG. To sommurize the above, the generic magnetic reluctance of each portion of the magnetic circuit is calculated based on (1), the magnetic flux based on (2) and the output torque based on (3).…”

“…In addition, the mechanical gear involves several well-known drawbacks: physical contact (friction) between the teeth, need for lubrication, local heat, material fatigue, and consequent mechanical losses [1]. In the case of magnetic gears (MGs), these drawbacks are avoided [2], [3], [4]. In this context, our research proposes a propulsion unit that eliminates mechanical transmission.…”

Design and Analysis of a Permanent Magnet Vernier Machine with Non-Uniform Tooth Distribution

“…In addition, the electromagnetic force and eccentricity resulted by the axial-flux topology or unbalanced design have been discussed in [9][10][11]. In [12], a dual stator axial-flux PMVM with spoke type magnets for the flux focusing effect is proposed. Moreover, an axial-flux PMVM [13] which has high efficiency with dual-rotor of consequent-pole topology and one yoke-less concentrated-winding stator is proposed.…”

“…To restrict the cogging torque, many structural methods are used in slot-tooth, such as optimized local sensitivity parameters [20], skewing [21], and so on. Magnets with notches are proposed to produce discrete skew effect which could reduce the cogging torque and torque ripples [12]. The authors of [22,23] propose that the total cogging torque is the summation of each slot, and eliminates the specific lower harmonics to reduce the cogging torque by offsetting the slots or magnets.…”

Analysis and Optimization of Axial Flux Permanent Magnet Machine for Cogging Torque Reduction

“…A 3D Pareto front linear induction motor with finite element model evaluation is optimized and analyzed in [28]. This paper performs the well-known, simple and practical optimization approach due to its suitability for non-linear data, as implemented in [29,30].…”