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This study introduces a novel methodology based on the idea of double Fourier series and coil segmentation, performed based on governing equations, with harmonic magnetic field analysis of a double-sided air-cored superconducting linear synchronous motor for electrodynamic suspension train. This method can solve the harmonic magnetic field generated by arbitrarily shaped coils. First, with rectangular-shaped coils and race-track-shaped coils as examples, the process of calculating harmonic magnetic field using the proposed method is introduced comprehensively, and the influence of the end effect is also considered. Second, based on the solution results of the harmonic magnetic field, a modeling method that can quickly solve no-load superconducting flux linkage, no-load back EMF, and three-dimensional (3-D) electromagnetic forces without losing accuracy is presented, which is verified by finite element simulation. Finally, two static tests are designed. The effectiveness of the proposed method is verified by the test results of static thrust and static normal force. [ABSTRACT FROM AUTHOR]

A novel design method for the primary structure of a double-sided long-primary fractional-slot concentrated winding permanent magnet linear synchronous motor (DSLP-FSCW-PMLSM) is proposed in this article. Different from the traditional symmetric primary structure, the primary structure obtained by the proposed design method has two asymmetric primary cores and two asymmetric primary windings. This unique structure can reduce the variation of the flux density caused by the primary core slotting, and can effectively reduce the slot harmonic contents of the armature reaction magnetic field; thus, it can significantly reduce secondary eddy current losses. First, the basic structure is introduced. The air-gap magnetic field of permanent magnet and armature reaction are analyzed in detail. Second, the performance of the proposed motor is analyzed by means of three dimensional finite element method and compared with the traditional motor. The focus is on secondary materials, secondary eddy current losses, thrust, pole arc coefficient, magnet skew angle, and efficiency. Last, experiments are conducted on two prototypes of DSLP-FSCW-PMLSM. The validity of the proposed topology is verified by the test results of static thrust, back electromotive force, and armature reaction air-gap magnetic field. [ABSTRACT FROM AUTHOR]

With the development of high performance processing system, high precision Permanent Magnet Linear Synchronous Motor (PMLSM) has been the focus of research. This paper provides a novel double-sided PMLSM with quasi- sinusoidal ring windings, to reduce the thrust ripple while keep the average thrust at a suitable value. Firstly, the distributions of the magnetic fields in this motor are analyzed, the low-order harmonics of armature magnetic field induced by the quasi- sinusoidal ring windings are studied, by equivalent magnetizing current (EMC) method. The winding factor and the Back Electromagnetic Force of this PMLSM are analyzed theoretically and verified by finite-element (FEM) method, based on the specific structure of quasi-sinusoidal ring windings. Furthermore, the electromagnetic thrust analysis is provided, which is aimed at the influence of the novel winding structure. Finally, a prototype of the double-sided PMLSM with quasi-sinusoidal ring windings is manufactured to verify the effectiveness of the topology proposed in this research. The presented results show that this novel motor can provide a great thrust property, it has a potential in high performance industry applications. [ABSTRACT FROM AUTHOR]

The maglev linear motor has three degrees of motion freedom, which are respectively realized by the thrust force in the x-axis, the levitation force in the z-axis and the torque around the y-axis. Both the thrust force and levitation force can be seen as the sum of the forces on the three windings. The resultant thrust force and resultant levitation force are independently controlled by d-axis current and q-axis current respectively. Thus, the commonly used dq transformation control strategy is suitable for realizing the control of the resultant force, either thrust force and levitation force. However, the forces on the three windings also generate additional torque because they do not pass the mover mass center. To realize the maglev system high-precision control, a maglev linear motor with a new structure is proposed in this paper to decrease this torque. First, the electromagnetic model of the motor can be deduced through the Lorenz force formula. Second, the analytic method and finite element method are used to explore the reason of this additional torque and what factors affect its change trend. Furthermore, a maglev linear motor with a new structure is proposed, with two sets of 90 degrees shifted winding designed on the mover. Under such a structure, the mover position dependent periodic part of the additional torque can be offset. Finally, the theoretical analysis is validated by the simulation result that the additionally generated rotating torque can be offset with little fluctuation in the proposed new-structure maglev linear motor. Moreover, the control system is built in MATLAB/Simulink, which shows that it has small thrust ripple and high-precision performance. [ABSTRACT FROM AUTHOR]

With the quick development of electromagnetic propulsion systems, permanent magnet linear synchronous motors (PMLSMs) have been the focus of research for high-performance propulsion systems. Compared with traditional windings, two ring windings with novel structures and better performance for PMLSMs are proposed: the single-layer ring windings are suitable for high-power systems; the double-layer ring windings can be adopted in low fluctuation systems. This paper first analyzes the electromagnetic parameters of the ring windings based on the equivalent magnetizing current method to verify the availabilities of ring windings. The main parameters of two ring windings are compared to achieve the optimization guides. Then, the magnetic fields and thrust characteristics of ring windings and traditional lap windings are analyzed by the finite-element method, and the independent magnetic field of ring winding ends is verified. And then a prototype motor with double-layer ring windings was manufactured and experimentally tested, the measurement data were matched with the theoretical calculations. The results illustrate that the PMLSM with ring windings has higher thrust density and lower thrust ripple, ring winding structure is more suitable for electromagnetic propulsion systems. [ABSTRACT FROM PUBLISHER]

This paper presents a novel parallel magnetic path hybrid excitation linear eddy current brake. The eddy current brake using parallel magnetic path scheme with the presence of the PMs, whose flux lines in the primary are oppositely directed with respect to the flux lines by the excitation windings, has the effect of mitigating the saturation of the iron in the teeth of the primary. This allows the brake to be fed with more intense currents improving the braking force. The structure and working principle are introduced. The analytical model was found using the equivalent magnetic circuit method and the layer theory approach. The design method of the eddy current brake was studied using the finite element method. Compared with traditional induction motors and synchronous motors, the design method of the eddy current brake has not been proposed. Therefore, in this paper, the design parameters of the hybrid excitation linear eddy current brake were gradually determined by consulting the design method of the linear induction motor and linear synchronous motor, and a design flowchart was proposed. Finally, a prototype of hybrid excitation linear eddy current brake was created and an experimental study of the eddy current brake was conducted. [ABSTRACT FROM PUBLISHER]

In this paper, a bidirectional cross-linking transverse flux permanent magnet synchronous motor is presented, which has a larger space utilization ratio than the traditional transverse flux machine. The stator core unit can make full use of rotor permanent magnets, and effectively increases no-load back-electromotive force (back-EMF), with the features of easy manufacturing. The structure and the driving principle of this motor are introduced. The 3-D magnetic circuit model is established, and the analytical expression of the no-load back-EMF and the torque are derived. In addition, the magnetic field and torque are analyzed by the 3-D finite element method (FEM). A prototype was designed and manufactured. The back-EMF and static torque experiments were carried out. The theoretical analyses agreed with the experimental results well. That verified the validity of the theoretical analysis. [ABSTRACT FROM AUTHOR]

This paper deals with the characteristic analysis of a long-stroke synchronous permanent magnet planar motor. The planar motor which employs a 2-D permanent magnet array for the stator, is suitable for the long-stroke applications since the moving coils can move freely. Operation principle and structure of this planar motor are introduced. Characteristics such as flux density, thrust and back-EMF are obtained analytically and compared with the finite element simulation results. A prototype motor is manufactured and successfully tested. The measured values are also in good agreement with the simulation ones. [ABSTRACT FROM PUBLISHER]

As the exploitation of astrospace deepens, many new types of space-based electromagnetic launchers (EMLs) have aroused wide attention and discussions. Compared with traditional slotted electromagnetic linear launchers, a slotless-plate permanent-magnet linear synchronous motor can easily meet demands such as flexible structure, light weight, and high control precision for space use. This paper analyzes the magnetic field of the slotless inverted- U structure based on the equivalent-magnetizing-current method. The validity of this technique for integral-slot configuration is confirmed with finite-element analysis. Then, the influence of the main design parameters is investigated, and design optimization guides are established for the selection of the key design parameters. To reach the suitable air-gap flux density here, some new constructional optimization details are discussed. Design optimization is also performed to fulfill enough thrust for the EML system. [ABSTRACT FROM AUTHOR]

Abstract: Permanent magnetic linear synchronous machines (PMLSMs) are playing a more important role either in transportation systems or magnetic launch systems, for the excellent advantages. It is indispensable to high performance controllers that some machine parameters are known such as the direct axis (d-axis) and quadrature axis (q-axis) inductances. In this paper, self and mutual inductances of the three-phase winding are deduced by basic electric machinery theory, and the measured inductances are analyzed since the mutual inductances and the corresponding terminals among three-phase windings are changing as different phase winding is concerned. The d- and q-axis inductances are measured with the designed circuit, and the experimental measurement method is validated by the comparison between the experimental and finite element method (FEM) results. [Copyright &y& Elsevier]