Magnetic Field Distribution and Levitation Force Calculation in HTSC-PMG Maglev Vehicles

Abstract

Abstract-This paper presents a new analytical method for predicting magnetic field distribution and levitation force in three configurations of high temperature superconducting (HTSC) maglev vehicles. The permanent magnet guideways (PMG) are composed with ferromagnetic materials and NdFeB permanent magnets. The proposed analytical model is based on the resolution in each region of Laplace's and Poisson's equations by using the technique of separation of variables. For the study, we consider the HTSC as a perfect diamagnetic material. The boundary conditions and Fourier series expansion of interfaces conditions between each region are used to find the solution of magnetic field. The developed analytical method is extended to compute the magnetic field distribution generated by the three types of PMGs when removing the HTSC bulk. Magnetic field distribution and vertical force obtained analytically are compared with those issued from the finite element method (FEM).

Investigation of the levitation force of field-cooled YBCO and MgB2disks as functions of temperature

“…Although the efficiency of numerical calculations for the simulation of levitating systems is obvious [12][13][14][15][16][17], analytical approaches can be more appropriate for understanding their physics. Various models based on the subdomain model and boundary value problems [18], first principles [11,19] and magnetic images have been proposed [20][21][22]. However, some of them do not account for the hysteresis of the force cycles [18,19] and they often require cumbersome calculations.…”

“…Various models based on the subdomain model and boundary value problems [18], first principles [11,19] and magnetic images have been proposed [20][21][22]. However, some of them do not account for the hysteresis of the force cycles [18,19] and they often require cumbersome calculations. Otherwise, the magnetic images models suppose that the magnetic moment induced in the superconductor by an applied field depends only on the magnetizing source [23].…”

Critical current density and current distribution in field cooled superconducting disks

“…It yields a good reproduction of the measurements. Concerning the levitation force, Boughrara and Ibtiouen [32] have proposed a method based on the subdomain model and boundary value problems, that results in the same magnetic field distribution and interaction force between a bulk superconductor and a magnetic guideway as finite element calculations. Although it requires less computer time than this last technique, the implementation of this method remains complex.…”

Field homogeneity improvement of maglev NdFeB magnetic rails from joints

“…Okano et al ( 2004 ) and Lin et al ( 2011 ) calculated the magnetic field inhomogeneity between two segments of the conventional unimodal magnetic rail and put forward some improvement countermeasures. The cost of the Halbach-type magnetic rail is just about 38 % of that of conventional unimodal magnetic rail per kilometer (Wang et al 2002 and Del-Valle et al 2011 ), while the levitation efficiency (N/cm 3 ) is about 2.85 times larger (Deng et al 2008 ), and thus has been widely used or reformed for the maglev applications (Guo et al 2010 ; Deng et al 2013 ; Boughrara et al 2013 ). But until recently, the method to improve magnetic field homogeneity of the Halbach-type magnetic rail with joint gaps is so limited that it is necessary to optimize the Halbach-type magnetic rail joint to guarantee the riding comfort of the HTS maglev vehicle.…”