Papers by Keyword: Permanent Magnet

Abstract: This paper presents the design modeling and analysis of linear permanent magnet generator for wave energy conversion using finite element method. The time-stepping finite element technique is used to determine electromagnetic characteristics and analyze the efficiency. The main parts such as; copper loss is analyzed on the different variation of winding input excitation and the core loss is determined based on various specific loss curves data in order to analyze its effect on frequency. The influence of main dimension of stator is analyzed on electromagnetic characteristic and copper loss.

Abstract: Flux switching machines (FSMs), new type of electric machines with unique operating principles have been introduced and published recently. FSMs contain armature and excitation sources on the stator with robust rotor structure. According to rotor structure FSMs can be classified into two types namely salient pole rotor and segmental pole rotor. Various topologies have been studied and published using both rotor structures, however salient pole rotor has a demerit of less torque generation due to longer flux path resulting flux leakage surrounding the rotor. In this paper a new structure of hybrid excitation FSM (HEFSM) with segmental rotor is proposed and a comparative analysis with the invented field excitation FSM (FEFSM) and permanent magnet FSM (PMFSM) is presented. Initially, coil arrangement tests are examined to confirm the operating principle of HEFSM with segmental rotor. Moreover, the cogging torque, induced voltage, magnetic flux, torque at various armature current densities and power characteristics are observed based on 2D-finite element analysis (FEA).

Abstract: This paper introduces the design of permanent magnet that can been used to small nuclear magnetic resonance (NMR) system, and its static magnetic field simulation analysis uses Ansoft's Maxwell software. According to the theory of magnetic circuit design and the performance requirements of magnetic field, An H-style permanent magnetic actuator has been designed, and it can generate uniform magnetic field larger than 0.4 T in the interested region of this actuator. The static magnetic field simulation analysis of this permanent magnetic actuator has done by Ansoft's Maxwell 3D software, and the experimental results show that the design of permanent magnet can meet the requirements.

Abstract: 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.

Abstract: The current method is presented to calibrate the constant of Helmholtz coils. Two measurement methods of magnetic field strength are proposed and compared. In order to improve the accuracy, the influence of geomagnetic field is eliminated by changing direction of the magnetic field of Helmholtz coils. When the magnetic field strength is measured by Guassmeter, the calibration uncertainty is 0.12% (k=2). When the magnetic field strength is measured by Fluxmeter and search coil, the calibration uncertainty is 0.30% (k=2).

Abstract: It is still a difficult problem to solve for a suspension system simultaneously to hold the body of the car in comfort and to execute the requirements of other safety systems like ABS, ESP, steer-by-wire, etc systems. Passive suspension systems are unlikely to provide a solution, the introduction of semi-active suspensions in the practical use is necessary. A possible solution could be a permanent magnetic (PM) synchronous tube generator, which can operate as a controllable shock absorber parallel with energy recuperative operation. Designer software is realized, to calculate the geometrical and electrical parameters of permanent magnetic (PM) or high temperature superconductor (HTS) magnets for arbitrary vehicle suspension systems

Abstract: This paper presents three-dimensional boundary element analysis for coupled magnetic field and moving problem. The method is applied to improve transmission characteristics of a magnetic gear and the usefulness is demonstrated. The gear has two movers consisting of permanent magnets and they rotate with different velocity. The double gap moving problem is very time consuming, because the mesh has to be regenerated at each time step or prepared many patterns previously. The use of the boundary element method is suitable for this problem, because meshes are required around only surfaces of considering objects and the objects can be rotated any angle according to the moving simulation. In this paper, the technique to reduce unknown variables in the boundary element equations utilizing symmetrical construction is proposed.

Abstract: This paper presents vibration characteristics of a hybrid magnetic suspension model combining functions of a magnetic spring and a magnetic damper. Dynamic simulations considering the moving equation are performed with the step-by-step method based on the time-domain three-dimensional axisymmetric finite element method. The results demonstrate that the proposed hybrid model is effective to improve the performance to attenuate vibrations.

Abstract: This paper presents a magnetic coupling for a large-sized mixer, which is separated by a vessel wall. In order to improve the transmission-torque, the magnetic material attached magnetic-flux concentrated surface permanent magnet (MCSPM) arrangement is applied to the magnetic coupling and the construction is optimized. The results show that the MCSPM arrangement is very effective to improve the air-gap magnetic flux density and the transmission torque even quantity of very few permanent magnets.

Abstract: the magnetic dipole model of the cylindrical permanent magnet was introduced. Then, based on Ansoft software, the simulation model of the cylindrical permanent magnet was established, and the influence of some parameters, such as the height, radius and magnetization direction on the magnetic induction intensity ,were studied; at the same time, under these two models the calculation was compared, the result shows the the magnetic dipole model is applied on condition that distance is nine times greater than the cylindrical permanent magnet size.