Seok-Myeong Jang

Design and Analysis of a High-Speed Brushless DC Motor for Centrifugal Compressor

This paper describes the design and analysis of a high-speed and high-power density BLDC motor for a 50-kW, 70 000-rpm class centrifugal compressor. Design criteria and power loss analysis of the high-speed machine structure are described by analytical method, and the results are validated by finite element method. And then, the prototype machine has been fabricated and tested. The experimental results confirmed the validity of the proposed design and analysis scheme of the high-speed BLDC motor

Improved Analytical Model for Electromagnetic Analysis of Axial Flux Machines With Double-Sided Permanent Magnet Rotor and Coreless Stator Windings

This paper deals with the experimental verification and electromagnetic analysis of an axial flux machine with a double-sided permanent magnet (PM) rotor and coreless stator windings, based on analytical field computation. Employing a magnetic vector potential and a 2-D analytical model, magnetic fields produced by PMs are obtained. The 3-D problem is solved by introducing a special function for the radial position. Then, the analytical solutions for back emf, electromagnetic torque, and efficiency of the PM-type axial flux machines are derived by using the magnetic field solutions and considering simple equivalent circuits. The analytical results are validated extensively by 3-D FE results. Test results such as back-emf, torque, and efficiency measurements are also presented to show the effectiveness of the analyses.

Magnet Pole Shape Design of Permanent Magnet Machine for Minimization of Torque Ripple Based on Electromagnetic Field Theory

This paper deals with the magnet pole shape design of permanent magnet machines for the minimization of torque ripple based on electromagnetic field theory. On the basis of a magnetic vector potential and a two-dimensional (2-D) polar system, analytical solutions for flux density due to permanent magnet (PM) and current are obtained. In particular, the analytical solutions for mathematical expressions of magnets with different circumferential thicknesses can be solved by introducing improved magnetization modeling techniques, resulting in accurate calculations of electromagnetic torque. The analytical results are validated extensively by nonlinear finite element method (FEM). Test results such as back-emf measurements are also given to confirm the analyses. Finally, on the basis of derived analytical solutions, a reduction of torque ripple can be achieved.

Design and analysis of helical motion permanent magnet motor with cylindrical Halbach array

In this paper, it deals with the application of two types of cylindrical Halbach array to permanent magnet motor. Halbach arrays have been used for permanent magnet arrays of planar linear, cylindrical rotary, and cylindrical linear motor, etc. In particular, their self-shielding property has been highlighted as a desirable feature for electrical machines and makes them eminently appropriate for use in linear and rotary machines.

Analysis and experimental verification of moving-magnet linear actuator with cylindrical Halbach array

This paper deals with analysis and experiments of moving-magnet linear actuators with cylindrical Halbach arrays. On the basis of analytical two-dimensional field solutions, this paper predicts magnetic fields, thrust, flux linkage, and back electromagnetic fluctuation. The results are validated extensively by comparison with finite element analysis. Test results such as thrust measurements are also given to confirm the analysis.

Design and analysis of high speed slotless PM machine with Halbach array

Slotless machines have been applied for a very high rotational speed and/or the ripple-free torque. In this paper, slotless machines equipped with external 4-pole field Halbach and radially magnetized PM array for electro-mechanical battery. This paper describes the comparison of the design guidelines, magnetic field characteristics, required magnet volume and optimal thickness of windings for two types of PM rotors.

Design criteria for detent force reduction of permanent-magnet linear synchronous motors with Halbach array

Summary form only given. This paper presents the design criteria for the detent force reduction of the permanent magnet linear synchronous motor (PMLSM) with Halbach array. There are three approaches to improve the power efficiency of short PM pole-type LSMs: (1) the comparison of the magnetic field and forces of two types of PMLSM-a PMLSM with a Halbach array (HA-PMLSM) and a PMLSM with a conventional array (CA-PMLSM); (2) the determination of PM length/slot pitch of the two types with minimum detent force; and (3) the comparison of the force performance of two types with the minimum detent force.

The characteristics analysis of eddy current brake system using the linear Halbach array

Summary form only given. The eddy current brake system ofa high-speed railway has been developed because of the mechanical adhesion limit. It have been used in magnetic levitation applications and in high velocity trains in order to avoid the abrasion of a mechanical disc brake. The eddy current brake system with permanent magnet has a simple structure, rugged characteristics and low cost because of no control and power system. In this paper, the characteristics analysis of an eddy current brake system using the linear Halbach array are analyzed by the analytical method and FEM.

Comparison of three types of PM brushless machines for an electro-mechanical battery

The paper reports on the comparison of three types of permanent magnet machines as the motor/generator for an electromechanical battery. To apply to high-speed drives, slotted, slotless ring-wound and coreless Halbach machines are designed to have the same capability and limited size. Three types are also compared with respect to their topology, size, magnetic field, inductance, torque and generating voltage, loss, and efficiency.

The influence of magnetization pattern on the rotor losses of permanent magnet high-speed machines

This paper deals with the comparison of two types of permanent magnet high-speed machines. Specifically, the effect of permanent magnet magnetization pattern on the rotor losses is investigated. On the basis of analytical field analysis and two-dimensional (2-D) finite-element method, this paper predicts the flux harmonics and rotor losses under no-load condition. It is shown that the Halbach magnetization is superior to parallel magnetization in terms of producing rotor losses.