scholarly journals Fourier decomposition of segmented magnets with radial magnetization in surface-mounted PM machines

2017 ◽  
Vol 68 (6) ◽  
pp. 470-475
Author(s):  
Tow Leong Tiang ◽  
Dahaman Ishak ◽  
Chee Peng Lim
Keyword(s):  
Magnetic Field ◽  
Field Model ◽  
Open Circuit ◽  
Operating Conditions ◽  
Fourier Decomposition ◽  
Field Distributions ◽  
Rotor Pole ◽  
Pole Surface ◽  
2D And 3D ◽  
The Magnetic Field

AbstractThis paper presents a generic field model of radial magnetization (RM) pattern produced by multiple segmented magnets per rotor pole in surface-mounted permanent magnet (PM) machines. The magnetization vectors from either odd- or even-number of magnet blocks per pole are described. Fourier decomposition is first employed to derive the field model, and later integrated with the exact 2D analytical subdomain method to predict the magnetic field distributions and other motor global quantities. For the assessment purpose, a 12-slot/8-pole surface-mounted PM motor with two segmented magnets per pole is investigated by using the proposed field model. The electromagnetic performances of the PM machines are intensively predicted by the proposed magnet field model which include the magnetic field distributions, airgap flux density, phase back-EMF, cogging torque, and output torque during either open-circuit or on-load operating conditions. The analytical results are evaluated and compared with those obtained from both 2D and 3D finite element analyses (FEA) where an excellent agreement has been achieved.

scholarly journals Analysis and optimisation of an axial flux permanent magnet coreless motor based on the field model using the superposition principle and genetic algorithm

2016 ◽  
Vol 65 (3) ◽  
pp. 601-611 ◽  
Author(s):  
Rafał M. Wojciechowski
Keyword(s):  
Magnetic Field ◽  
Permanent Magnet ◽  
Field Model ◽  
Superposition Principle ◽  
Electromagnetic Torque ◽  
Axial Flux ◽  
Magnetic Field Simulation ◽  
Field Distributions ◽  
Field Simulation ◽  
The Magnetic Field

Abstract In the paper, methodologies for the magnetic field simulation in an axial flux permanent magnet coreless (AFPMC) motor have been proposed and discussed. Two approaches have been considered and investigated, both based on representing the 3D field distribution by superimposing axisymmetric 2D patterns. The first of studied approaches applies directly to the Biot-Savart law while the second uses a 2D axisymmetric finite element method. The selected results of magnetic field distributions and electromagnetic torque characteristics for the considered AFPMC motor have been presented and compared with results obtained using the commercial FEM package ‘Maxwell’. The elaborated algorithms have been incorporated into the design routines allowing multi-parameter optimisation of the considered motor construction.

scholarly journals A case study of the plasma in the magneto-sheath using the numerical magnetosheath-magnetosphere model and THEMIS measure-ments

2018 ◽  
Vol 145 ◽  
pp. 03004
Author(s):  
Polya Dobreva ◽  
Olga Nitcheva ◽  
Monio Kartalev
Keyword(s):  
Magnetic Field ◽  
Field Model ◽  
Specific Aspect ◽  
Plasma Parameters ◽  
Ion Density ◽  
Magnetic Field Model ◽  
Wind Spacecraft ◽  
The Mean ◽  
The Magnetic Field

This paper presents a case study of the plasma parameters in the magnetosheath, based on THEMIS measurements. As a theoretical tool we apply the self-consistent magnetosheath-magnetosphere model. A specific aspect of the model is that the positions of the bow shock and the magnetopause are self-consistently determined. In the magnetosheath the distribution of the velocity, density and temperature is calculated, based on the gas-dynamic theory. The magnetosphere module allows for the calculation of the magnetopause currents, confining the magnetic field into an arbitrary non-axisymmetric magnetopause. The variant of the Tsyganenko magnetic field model is applied as an internal magnetic field model. As solar wind monitor we use measurements from the WIND spacecraft. The results show that the model quite well reproduces the values of the ion density and velocity in the magnetosheath. The simlicity of the model allows calulations to be perforemed on a personal computer, which is one of the mean advantages of our model.

scholarly journals Retrieving lithospheric magnetisation distribution from magnetic field models

2019 ◽  
Author(s):  
V Lesur ◽  
F Vervelidou
Keyword(s):  
Magnetic Field ◽  
Cost Function ◽  
Spherical Harmonic ◽  
Field Model ◽  
Harmonic Model ◽  
Whole Process ◽  
Magnetic Field Model ◽  
The Cost ◽  
Spherical Harmonic Model ◽  
The Magnetic Field

Summary We investigate to which extent the radially averaged magnetisation of the lithosphere can be recovered from the information content of a spherical harmonic model of the generated magnetic field when combined with few simple hypotheses. The results obtained show firstly that a hypothesis of magnetisation induced by a field of internal origin, even over a localised area, is not sufficient to recover uniquely the radially averaged magnetisation and, secondly, that this magnetisation can be recovered when a constant magnetisation direction is assumed. An algorithm to recover the magnetisation direction and distribution is then described and tested over a synthetic example. It requires to introduce a cost function that vanishes when estimated in a system of coordinates with its Z axis aligned with the magnetisation direction. Failing to find a vanishingly small value for the cost function is an indication that a constant magnetisation direction is not a valid hypothesis for the studied magnetic field model. The range of magnetisation directions that are compatible with the magnetic field model and a given noise level, can also be estimated. The whole process is illustrated by analysing a local, isolated maximum of the Martian magnetic field.

scholarly journals Velocity-Magnetic Field Correlation of Pulsars

1996 ◽  
Vol 160 ◽  
pp. 49-50
Author(s):  
Naoki Itoh ◽  
Takemi Kotouda
Keyword(s):  
Magnetic Field ◽  
Constant Magnetic Field ◽  
Field Model ◽  
Transverse Velocity ◽  
Distribution Model ◽  
Recent Measurement ◽  
Apparent Correlation ◽  
Magnetic Field Model ◽  
Field Correlation ◽  
The Magnetic Field

Monte Carlo simulations of the evolution of pulsars are carried out in order to compare with the recent measurement of the pulsar transverse velocity by Lyne & Lorimer (1994). The new electron density distribution model of Taylor & Cordes (1993) is adopted in the simulation. Accurate pulsar orbits in the Galactic gravitational field are calculated. It is found that the constant magnetic field model of pulsars can account for the new measurement of the pulsar transverse velocity and the apparent correlation between the strength of the magnetic field and the transverse velocity of the pulsars. The present finding confirms the validity of the constant magnetic field model of pulsars and consolidates the idea that the apparent correlation between the strength of the magnetic field and the transverse velocity of the pulsars is caused by observational selection effects.

scholarly journals Comparative Study on Planetary Magnetosphere in the Solar System

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1673
Author(s):  
Ching-Ming Lai ◽  
Jean-Fu Kiang
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Solar System ◽  
Comparative Study ◽  
Magnetic Reconnection ◽  
Tilt Angle ◽  
Planetary Magnetosphere ◽  
Field Distributions ◽  
Mhd Simulations ◽  
The Magnetic Field

The magnetospheric responses to solar wind of Mercury, Earth, Jupiter and Uranus are compared via magnetohydrodynamic (MHD) simulations. The tilt angle of each planetary field and the polarity of solar wind are also considered. Magnetic reconnection is illustrated and explicated with the interaction between the magnetic field distributions of the solar wind and the magnetosphere.

Orientation dependence of the magnetic field distributions in large single crystals of

2006 ◽  
Vol 374-375 ◽  
pp. 225-228 ◽  
Author(s):  
W.J. Kossler ◽  
A.J. Greer ◽  
R.N. Dickes ◽  
D. Sicilia ◽  
Y. Dai
Keyword(s):  
Magnetic Field ◽  
Single Crystals ◽  
Orientation Dependence ◽  
Field Distributions ◽  
The Magnetic Field

scholarly journals Effects of Vortex Pinning on the Temperature Dependence of the Magnetic Field Distributions in Superconductors

2012 ◽  
Vol 30 ◽  
pp. 245-248
Author(s):  
W.J. Kossler ◽  
Allan J. Greer ◽  
Dale R. Harshman ◽  
C.E. Stronach ◽  
A.C. Shockley ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Temperature Dependence ◽  
Vortex Pinning ◽  
Field Distributions ◽  
The Magnetic Field

Small-scale magnetic fields in turbulence: Saffman's approximation revisited

1980 ◽  
Vol 99 (3) ◽  
pp. 481-493
Author(s):  
Ralph Baierlein
Keyword(s):  
Magnetic Field ◽  
Numerical Evaluation ◽  
Two Dimensions ◽  
Three Dimensions ◽  
Small Scale ◽  
Fluid Element ◽  
Relative Time ◽  
Fourier Decomposition ◽  
The Subject ◽  
The Magnetic Field

The subject is the small-scale structure of a magnetic field in a turbulent conducting fluid, ‘small scale’ meaning lengths much smaller than the characteristic dissipative length of the turbulence. Philip Saffman developed an approximation to describe this structure and its evolution in time. Its usefulness invites a closer examination of the approximation itself and an attempt to place sharper limits on the numerical parameters that appear in the approximate correlation functions, topics to which the present paper is addressed.A Lagrangian approach is taken, wherein one makes a Fourier decomposition of the magnetic field in a neighbourhood that follows a fluid element. If one construes the viscous-convective range narrowly, by ignoring magnetic dissipation entirely, then results for a magnetic field in two dimensions are consistent with Saffman's approximation, but in three dimensions no steady state could be found. Thus, in three dimensions, turbulent amplification seems to be more effective than Saffman's approximation implies. The cause seems to be a matter of geometry, not of correlation times or relative time scales.Strictly-outward spectral transfer is a characteristic of Saffman's approximation, and this may be an accurate description only when dissipation suppresses the contributions from inwardly directed spectral transfer. In the spectral region where dominance passes from convection to dissipation, one can generate expressions for the parameters that arise in Saffman's approximation. Their numerical evaluation by computer simulation may enable one to sharpen the limits that Saffman had already set for those parameters.

scholarly journals Analysis of Juno perijove 1 magnetic field data using the Jovian paraboloid magnetospheric model

2018 ◽  
Author(s):  
Ivan A. Pensionerov ◽  
Elena S. Belenkaya ◽  
Stanley W. H. Cowley ◽  
Igor I. Alexeev ◽  
Vladimir V. Kalegaev ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Field Model ◽  
Outer Edge ◽  
Optimal Parameters ◽  
Magnetic Field Data ◽  
Analytic Expressions ◽  
Magnetic Field Model ◽  
Current Systems ◽  
The Magnetic Field

Abstract. One of the main features of Jupiter's magnetosphere is its equatorial magnetodisc, which significantly increases the field strength and size of the magnetosphere. Juno measurements of the magnetic field during the perijove 1 pass have allowed us to determine optimal parameters of the magnetodisc using the paraboloid magnetospheric magnetic field model, which employs analytic expressions for the magnetospheric current systems. Specifically within the model we determine the size of the Jovian magnetodisc and the magnetic field strength at its outer edge.

scholarly journals General 3D Analytical Method for Eddy-Current Coupling with Halbach Magnet Arrays Based on Magnetic Scalar Potential and H-Functions

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8458
Author(s):  
Xiaoquan Lu ◽  
Xinyi He ◽  
Ping Jin ◽  
Qifeng Huang ◽  
Shihai Yang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Analytical Method ◽  
Eddy Currents ◽  
Scalar Potential ◽  
Fourier Decomposition ◽  
Field Distributions ◽  
Current Coupling ◽  
Current Calculation ◽  
Laplacian Equations

Rapid and accurate eddy-current calculation is necessary to analyze eddy-current couplings (ECCs). This paper presents a general 3D analytical method for calculating the magnetic field distributions, eddy currents, and torques of ECCs with different Halbach magnet arrays. By using Fourier decomposition, the magnetization components of Halbach magnet arrays are determined. Then, with a group of H-formulations in the conductor region and Laplacian equations with magnetic scalar potential in the others, analytical magnetic field distributions are predicted and verified by 3D finite element models. Based on Ohm’s law for moving conductors, eddy-current distributions and torques are obtained at different speeds. Finally, the Halbach magnet arrays with different segments are optimized to enhance the fundamental amplitude and reduce the harmonic contents of air-gap flux densities. The proposed method shows its correctness and validation in analyzing and optimizing ECCs with Halbach magnet arrays.

Sign in / Sign up

Export Citation Format

Share Document