Analytical Solution of the Magnetic Field in Permanent-Magnet Motors Taking Into Account Slotting Effect: No-Load Vector Potential and Flux Density Calculation

2009 ◽  
Vol 45 (5) ◽  
pp. 2097-2109 ◽  
Author(s):  
F. Dubas ◽  
C. Espanet
Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2522
Author(s):  
Guangdou Liu ◽  
Shiqin Hou ◽  
Xingping Xu ◽  
Wensheng Xiao

In the linear and planar motors, the 1D Halbach magnet array is extensively used. The sinusoidal property of the magnetic field deteriorates by analyzing the magnetic field at a small air gap. Therefore, a new 1D Halbach magnet array is proposed, in which the permanent magnet with a curved surface is applied. Based on the superposition of principle and Fourier series, the magnetic flux density distribution is derived. The optimized curved surface is obtained and fitted by a polynomial. The sinusoidal magnetic field is verified by comparing it with the magnetic flux density of the finite element model. Through the analysis of different dimensions of the permanent magnet array, the optimization result has good applicability. The force ripple can be significantly reduced by the new magnet array. The effect on the mass and air gap is investigated compared with a conventional magnet array with rectangular permanent magnets. In conclusion, the new magnet array design has the scalability to be extended to various sizes of motor and is especially suitable for small air gap applications.


2011 ◽  
Vol 52-54 ◽  
pp. 285-290
Author(s):  
Yi Chang Wu ◽  
Feng Ming Ou ◽  
Bo Wei Lin

The prediction of the magnetic field is a prerequisite to investigate the motor performance. This paper focuses on the magnetic field estimation of surface-mounted permanent-magnet (SMPM) motors based on two approximations, i.e., the magnetic circuit analysis and the finite-element analysis (FEA). An equivalent magnetic circuit model is applied to analytically evaluate the magnetic field of a SMPM motor with exterior-rotor configuration. The two-dimensional FEA is then applied to numerically calculate the magnetic field and to verify the validity of the magnetic circuit model. The results show that the errors between the analytical predictions and FEA results are less than 6%. It is of benefit to further design purposes and optimization of SMPM motors.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Xiaoting Zhang ◽  
Bingyi Zhang

In this study, an analytical model is established to efficiently compute the magnetic field and unbalanced magnetic pull (UMP) in axial-flux permanent-magnet motors (AFPMMs). The effects of stator slotting, end effect, and rotor eccentricity on the magnetic field and forces were investigated. Static and dynamic eccentricities are analyzed and considered in the model. An effective function of the air gap permeance was introduced for effect of the stator slots to compute the flux density. A specific coefficient function is defined to calculate the end effect. A Fourier transform is used to compute the variations of the permanent-magnet remanence and the air gap permeance due to the slotted stator opposite to a slotless stator. The unbalanced magnetic forces were evaluated as a function of the air gap magnetic field using analytical equations. The proposed analytical method dramatically reduces the model size and computational time. It can be applied to the analysis of AFPMMs and is much faster than the three-dimensional finite element method (FEM). By comparing with the obtained using the FEM, the model results are validated.


2014 ◽  
Vol 1017 ◽  
pp. 806-811
Author(s):  
Hideki Takezawa ◽  
Nobuhiro Yokote ◽  
Naotake Mohri

The effect of changes in the magnetic field on the magnetic flux density during the electrical discharge machining (EDM) of a permanent magnet is reported. During EDM of the permanent magnet, a second magnet for the external magnetic field was set up, and the internal temperature and surface magnetic flux density on the opposite surface of the permanent magnet during machining were evaluated. It was found that even though the internal temperature of the magnet remained unchanged, the surface magnetic flux density changed when the external magnetic field was varied. In addition, the magnetic field generated by the magnet changed when a plate with high permeability was pressed onto the surface of the permanent magnet.


2012 ◽  
Vol 466-467 ◽  
pp. 940-945
Author(s):  
Xiao Hui Lu ◽  
Jian Hong Liang

The paper presents the magnetic field distribution from the armature winding currents in the slotted air gap of surface-mounted permanent magnet (SMPM) motors using the Schwarz- Christoffel(SC) mapping. With the method, a slotted structure of SMPM motors is transformed into a geometrically simpler domain. Compared with the result from the finite element method, the accuracy of the method is verified. The presented work can be a basic tool for optimizing design and performance analysis of permanent magnet motors.


2011 ◽  
Vol 143-144 ◽  
pp. 154-158
Author(s):  
J.K. Si ◽  
M. Si ◽  
Hai Chao Feng

For each characteristic of surface-mounted permanent magnet motor and built-in permanent magnet motor, this paper presents a new rotor hybrid topologies structure of both the permanent magnet motors. Surface Mounted, built-in and hybrid permanent magnet motor topology model were established using the finite element method for to calculate the static magnetic field three structures of the motor. Comparative analysis of their contour distribution of the pole from the amplitude distribution within the air gap flux density and the flux density of the cloud were done. Air-gap magnetic field distribution in permanent magnet motor proposed new structure is more close to the sine, which is basis on the motor design, operation and so on.


Author(s):  
Jianqi Li ◽  
Yu Zhou ◽  
Jianying Li

This paper presented a novel analytical method for calculating magnetic field in the slotted air gap of spoke-type permanent-magnet machines using conformal mapping. Firstly, flux density without slots and complex relative air-gap permeance of slotted air gap are derived from conformal transformation separately. Secondly, they are combined in order to obtain normalized flux density taking account into the slots effect. The finite element (FE) results confirmed the validity of the analytical method for predicting magnetic field and back electromotive force (BEMF) in the slotted air gap of spoke-type permanent-magnet machines. In comparison with FE result, the analytical solution yields higher peak value of cogging torque.


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