Sang-Kyu Choi

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

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.

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.

Design and Experimental Evaluation of Synchronous Machine Without Iron Loss Using Double-Sided Halbach Magnetized PM Rotor in High Power FESS

The rotational loss is one of the most important problems in high-power flywheel energy storage system (FESS) which supplies the electrical energy from the mechanical rotation energy. In our FESS with PM synchronous motor/generator (PMSM/G) and non-contacting system, the rotational loss is mainly generated in the laminated iron stator when PM rotor mounted on the flywheel is rotated. Therefore, this paper presents design and evaluation of a PMSM/G model composed of double-sided Halbach magnetized PM rotor and ironless 3-phase winding stator to minimize speed reduction of the flywheel. For one such motor structure we give analytical formulae for its magnetic field and back-electromotive force in a uniform way via the magnetic vector potential. As a result of experiment, dynamic performance of a manufactured double-sided PMSM/G is evaluated by comparison with those of the slotless PMSM/G in the idling mode. The result shows that the presented PMSM/G can be applicable to the high-power FESS.

Development of high-speed brushless DC motor for turbo-compressor

This paper describes the design and analysis of a high-speed brushless DC motor for a 50-kW, 70-krpm turbo-compressor. Design criteria of optimization of the high-speed motor structure are described by 2-D analytical method with magnetic and mechanical constraints, and the results are validated by finite element analyses. And then, the prototype machine has been fabricated with the air bearing and liquid cooling system. The test results confirmed the validity of the proposed design and analysis of the high-speed brushless DC motor

Integrated motor propulsor magnet design with hybrid Halbach array for torque ripple reduction

Motivation for research Recently, integrated motor propulsors (IMPs) have been under extensive research and development because of the numerous advantages of underwater propulsion for vehicles, such as a simple, quiet, lightweight, and small-size structure [1].Recently, integrated motor propulsors (IMPs) have been under extensive research and development because of the numerous advantages of underwater propulsion for vehicles, such as a simple, quiet, lightweight, and small-size structure [1]. IMPs require minimized torque ripple for smooth and quiet operation when used in undersea vehicles or unmanned submarines. Thus, torque ripple reduction should be considered in the design stage.

Development of a High-Speed and High Power Density Brushless DC Motor for Turbo-Compressor

This paper presents the development of a high-speed and high power density brushless DC (BLDC) motor for a 50-kW, 70-krpm turbo-compressor. Important design criteria are established based on the two-dimensional (2-D) analytical method under several assumptions and the results are compared with the numerical solutions by the finite element analysis (FEA). A prototype machine was also fabricated and tested to confirm the analytical design.

Electromagnetic Analysis of High Speed Machines with Diametrically Magnetized Rotor for Flywheel Battery Applications

This paper investigates on the characteristics for the generation of electricity of high speed machine and derives analytical solutions for open-circuit field, armature reaction field and back-emf in terms of magnetic vector potential and a two dimensional (2-D) polar coordinate system. In particular, since the open-circuit field is essential for the prediction of a back emf, new magnetization modeling technique for diametrically magnetized rotor is presented. Finally, all analytical results are compared with those obtained from finite element (FE) analyses and, in particular, test results such as back-emf measurements are given to confirm the analysis.