Analytical modeling of the magnetic field in axial field flux-switching permanent magnet machines at no-load (original) (raw)
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IEEE Transactions on Magnetics, 2012
This paper presents a multi-slice analytical model for prediction of the open-circuit magnetic field in slotted semi-closed permanent-magnet axial flux synchronous machines. The technique is based on 2-D exact solution of the Maxwell's equations using the separation of variables method. The magnetic field expressions are developed in slots regions, slot opening regions, magnetic air gap regions, and permanent magnet regions leading to an exact calculation of the slot effects on the air gap magnetic field. The model is established considering that ferromagnetic parts are infinitely permeable, and end effects at inner and outer radii are neglected. The open circuit machine's global quantities (electromotive force and cogging torque) are then deduced from the local magnetic field expressions. Finally, the accuracy of the presented analytical model is validated by comparing its results to corresponding finite-element analyses for two different axial flux machines.
Renewable Energy and Power Quality Journal, 2012
The paper presents an analytical method in order to obtain the electromagnetic field distribution in an axial flux slotted permanent magnet machine under no-load conditions. The method solves the Laplace equation in the gap of an slotted machine via magnetic scalar potential. Once the magnetic scalar potential is defined, the magnetic flux density components are computed.. Results issued from the proposed model are compared with those stemming from a 3D finite-element method (FEM) simulation. In addition to permanent magnet machines, this technique can be applied to any 2D geometry with the restriction that the geometry should consist of rectangular regions.
Analytical Approach for Air-Gap Modeling of Field-Excited Flux-Switching Machine: No-Load Operation
IEEE Transactions on Magnetics, 2000
This paper presents a general and accurate approach to determine the no-load flux of field-excited flux-switching (FE-FS) machines. These structures are inherently difficult to model due to their doubly-slotted air-gap. This analytical approach is based on MMF-permeance theory. The analytical model developed is extensively compared to field distribution obtained with 2D Finite Element (2D FE) Simulations. The good agreement observed between analytical model and 2D FE results emphasizes the interest of this general approach regarding the computation time. Hence, this analytical approach is suitable for optimization process in presizing loop. Furthermore, based on the field model, classical electromagnetic performances can be derived, such as flux-linkage and back-electromotive force (back-EMF) and also, unbalanced magnetic force. Once again, FE results validate the analytical prediction, allowing investigations on several stator-rotor combinations, or optimization of the back-EMF.
Modeling and design of axial-flux permanent magnet machines: A new approach
In this paper, a modified analytic approach to the calculation of magnetic field in a slot-less, two-rotor axial-flux permanent magnet machine is presented. The analytic-modelling is based on calculation of scalar and vector magnetic potentials which are produced by the armature windings and the magnets. The magnet and the armature windings are modelled by a magnetization vector and a two-dimensional current sheet, respectively. The effects of the armature reaction and the harmonics of field are also considered. The simulation of magnetic field by the analytic model is compared with that of a two-dimensional finite element analysis. The proposed analytic model predicts the magnetic field within 5% compared to the finite element method. Ultimately, by using the analytic model in a genetic algorithm method, which is a known method in optimization, an optimum design of an axial-flux permanent magnet machine is presented.
A General Analytical No-Load Magnetic Model for Axial Flux Permanent Magnet Synchronous Machines
Iranian Journal of Science and Technology, Transactions of Electrical Engineering, 2018
A quasi-3-dimensional analytical no-load magnetic model for axial flux permanent magnet synchronous machines (AFPMSM) is proposed which can be generalized to different types of regular AFPMSMs. Magnetic flux density is obtained all over the nonferrous parts of the machine using the subdomain technique for a surface-mounted slotted AFPMSM. The cogging torque is also analytically calculated based on the Maxwell stress tensor. The results of the proposed method are compared with those of the finite element method, and an eligible compromise is observed.
IEEE Transactions on Magnetics, 2000
In this paper, an analytical approach for the prediction of the armature reaction field of field-excited flux-switching (FE-FS) machines is presented. The analytical method is based on the Magnetomotive Force (MMF)-permeance theory. The doubly-salient air-gap permeance, developed here, is derived from an exact solution of the slot permeance. Indeed, the relative slot permeance is obtained by solving Maxwell's equations in a subdomain model and applying boundary and continuity conditions. In addition, during a no-load study, we found that, regarding the stator-rotor teeth combination, phase distributions were modified. Hence, in this paper, phase MMF distributions, for q phases, several stator-rotor combinations and also phase winding distribution (single or double-layers) are proposed. We compare extensively magnetic field distributions calculated by the analytical model with those obtained from finite-element analyses. Futhermore, the model is used to predict the machine inductances. Once again, FE results validate the analytical prediction, showing that the developed model can be advantageously used as a design tool of FE-FS machine.
IEEE Transactions on Magnetics, 2021
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IET Electric Power Applications, 2018
The harmonic contents of principal performance characteristics in an electrical machine are important due to several reasons, especially because they influence the machine acoustic noise generation capability. Therefore, they should be accurately calculated considering the various electromagnetic effects involved in the machine operation. Accordingly, this study proposes a detailed analytical model for predicting the time waveforms and harmonic contents of the principal performance characteristics of a double-sided TORUS-type non-slotted axial flux permanent magnet motor with surface-mounted magnets at steady state under any given loading conditions. The armature-reaction magnetic field and inductances are exactly calculated considering both the effects of coil sides and end windings as well as that of the winding distribution. Most notably, the aggregate iron loss of machine and its influence on armature currents is precisely modelled based on the magnetic field distribution in iron parts. By establishing and solving the differential equation system of motor in the two cases with or without the neutral wire, the armature currents, speed and torque ripples, input/output powers, and copper and iron losses are all achieved with the entire harmonic content and highest accuracy. The comparison of results with those of finite element analysis and real test then validates the model.
Modeling of Flux Switching Permanent Magnet Machines With Fourier Analysis
IEEE Transactions on Magnetics, 2010
For applications demanding a high torque density and high speed capability, the flux switching permanent magnet machine is an excellent candidate. However, the double salient structure and nonlinear behavior increases the challenge to model the magnetic field distribution and torque output. To date, only the magnetic equivalent circuit (MEC) is employed to model the magnetic field in an analytical manner. However, the MEC method suffers from a coarse discretization and the need for a relative complex adjustment when rotor movement or a parametric sweep is considered. Therefore this paper discusses an alternative technique based on the harmonic or Fourier model which solves these difficulties.