• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.6
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• pp.1039-1046
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• 2007

This paper presents the analysis for power consumption, mechanical vibration and acoustic noise characteristics of the Coreless and Slotless Brushless DC motor in Digital Lightening Processor(DLP) Motor with the Air-Dynamic Bearing. The Coreless BLDC motor has not the stator yoke as well as the stator slot to remove the unbalance force by the interaction between the stator yoke and Air-Dynamic Bearing clearance. The assembling tolerance and the processing error make the air-gap difference between the magnet and the stator yoke .which occurs the unbalanced electro-magnetic force in the Slotless BLDC motor. It imposes the air-dynamic bearing on the disturbance force and makes the Air-Dynamic Bearing vibrated and noised. Also, The attractive force between the magnet and the silicon steel stator yoke increases the power consumption. In this paper, the power consumption, mechanical vibration and acoustic noise of the Coreless BLDC motor and the Slotless BLDC motor with the silicon steel stator yoke are simulated, analyzed, and tested using the manufactured proto-type motors with Air-Dynamic bearing. The simulated and tested results present that the Coreless BLDC motor without the silicon steel stator yoke has the lower mechanical vibration and noise ,and lower power consumption than the Slotless BLDC motor with the silicon steel stator yoke in Digital Lightening Processor Motor with Air-Dynamic Bearing.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.7
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• pp.315-322
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• 2001

High speed brushless permanent magnet(PM) machines need a key technology to minimize the iron core losses in stator and the eddy current losses in the retained sleeve and magnets caused by slotting harmonics. Thus, slotless or iron-coreless brushless PM machines have been applied for a very high rotational speed and/or the ripple-free torque. Unfortunately, slotless or coreless PM machines have lower open-circuit field than slotted and/or iron-cored types, which cause to reduce power density. Fortunately, Halbach array can generate the strong magnetic field systems without additional magnetic materials. In this paper, the 4-pole Halbach array is applied to the high speed machine and is compared with the radial magnetized PM array in field system. The iron-/air-cored stator of PM machine is constructed with/without winding slots. Open circuit magnetic fields of each type are presented from the analytical method and finite element method. Consequently, it is confirmed that the Halbach array field system with slotless stator is more suitable to the high speed motor because it has high flux density, sinusoidal flux distribution than others.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.68-70
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• 2004

This paper deals with comparison of magnetic field distribution in LOA with slotless/slot stator. We derived magnetic field solutions in terms of vector potential and cylinderical coordinates. In particular this paper accounts for slotting effect due to stator slot opening by introducing a 2-D relative permeance function. The results of predictions from the analysis are compared with corresponding finite element analysis.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.104-106
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• 2001

In this paper, it is object of design of high efficiency slotless BLDC motor using film coil. Slotless BLDC motor is able to have high efficiency property and low cogging torque, due to magnetization of stator core have constant contribution by slotless core. But it is difficult to make coil winding of slotless BLDC motor. So we make amateur of slotless BLDC motor using film coil. Film coil is fabricated by drilling, electro-plating and etching of copper/insulator/copper plate. In this paper, after design of slotless BLDC motor for moving axial blower, it is fabricated by NdFeB permanent magnet type rotor and film coil.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.981-982
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• 2011

This paper discusses design aspects of slotless permanent magnet generator for high performance and low speed applications. The airgap flux density in was obtained from finite element analysis and the design of a PM generator. The relatively large diameter stator laminations of such machines tend, therefore, to have a very thin back of core and narrow teeth, which make them expensive and difficult to manufacture. this thesis proposes an alternative PM generator topology featuring a slotless stator whose laminations are manufactured from a split core. The test results with a resistive load confirm the satisfactory operation of generator.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1177-1179
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• 2005

This paper presents the characteristic analysis of slotless tubular type Linear DC Motor with Permanent Magnet excitation as variation of magnetic pole-pitch ratio. The stator armature winding of this motor is designed to wind at inner stator around the mover mounted with permanent magnet. First the practical model of this motor is made and its parameter is measured, after this simulation is carried out. Comparing the simulation results as variation of pole-pitch ratio, it can be seen that the reaching ability makes it useful in applications requiring a small, direct-drive actuator, which is required to extend into a specially constrained environment.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.33-37
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• 2004

Slotless Permanent magnet Brushless DC Motor(PM BLDC) with the characteristics of high speed and high power density has been more widely used in industrial and automatic machine. Generally, PM BLDC meter is necessary that the three Hall-ICs evenly be distributed around the stator circumference in case of the 3 phase motor. The Hall-ICs are set up in this motor to detect the main flux from the rotor. therefore the output signal from Hall-ICs is used to drive a power transistor to control the stator winding current. However, instead of using three Hall-ICs, if only we used one Hall-IC, we estimate information of the others phase in sequence through a revolving rotor. This paper identified the characteristics and performance by using one Hall-IC for the 3 phase PM BLDC whose six stator and two rotor designed.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.665-669
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• 2004

Generally, Slotless PM BLDC drive system is necessary that the three Hall-ICs evenly be distributed around the stator circumference and encoder be installed in case of the 3 phase motor. So, the Hall-ICs are set up in this motor to detect the main flux from the rotor, and the output signal from Hall-ICs is used to drive a power transistor to control the winding current. However, instead of using three Hall-ICs and encoder, we used only two Hall-ICs for the permanent magnet rotor position and for the speed feedback signals, and also for a microcontroller of 16-bit type (80C196KC) with the 3 phase Slotless PM BLDC whose six stator and two rotor designed. Two Hall-IC Hc and $H_B$ are placed on the endplate at 120 degree intervals, and with these elements, we can estimate information of the others phase in sequence through a rotating rotor.

• Journal of Electrical Engineering and Technology
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• v.4 no.2
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• pp.255-265
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• 2009

This paper presents the acoustic noise and mechanical vibration reduction of a coreless brushless DC motor with an air dynamic bearing used in a digital lightening processor. The coreless brushless DC motor does not have a stator yoke or stator slot to remove the unbalanced force caused by the interaction between the stator yoke and the rotor magnet. An unbalanced force makes slotless brushless DC motors vibrate and mechanically noisy, and the attractive force between the magnet and the stator yoke increases power consumption. Also, when a coreless brushless DC motor is driven by a $120^{\circ}$ conduction type inverter, high frequency acoustic noise occurs because of the peak components of the phase currents caused by small phase inductance and large phase resistance. In this paper, a core-less brushless DC motor with an air dynamic bearing to remove mechanical vibration and to reduce power consumption is applied to a digital lightening processor. A $180^{\circ}$ conduction type inverter drives it to reduce high frequency acoustic noise. The applied methods are simulated and tested using a manufactured prototype motor with an air dynamic bearing. The experimental results show that a coreless brushless DC motor has characteristics of low power consumption, low mechanical vibration, and low high frequency acoustic noise.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.3
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• pp.174-181
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• 2014

Design procedure of LEG(Linear Electric Generator) is introduced by performing the time-domain analysis for the heaving motion of a floating buoy coupled with LEG. A vertical truncated buoy is selected as a point absorber and a double-sided Halbach array mover and cored slotless stator is adopted as a linear electric generator. LEG with a double-sided Halbach array mover and cored slotless stator is designed with the input data such as the heave motion velocity and wave exciting forces in time-domain. The validity of designed LEG is confirmed by performing generating-characteristic-analysis under the sinusoidal motion of a buoy, based on the numerical techniques such as FE(Finite Element) analysis. In particular, an ECM(Equivalent Circuit Method) is employed as the design tool for the prediction of generating characteristics under irregular wave conditions. Finally, we confirm that the ECM gives reasonable and fast results without sacrifice of accuracy.