• Journal of Power Electronics
• /
• v.5 no.3
• /
• pp.240-246
• /
• 2005

Considering the start-up and economical efficiency, the optical sensor technique using a slotted-disk and an opto-interrupter are appropriate, however, this method needs three opto-interrupters and a slotted-disk when driving the 6/4 pole SRM(switched reluctance motor). In this paper, we propose an economic method by replacing the conventional opto-interrupter and slotted-disk with only optical sensor which enables the motor to start up and forward and reverse operation. Also the control circuit includes only analog devices, which makes the process more economical.

• Proceedings of the KIEE Conference
• /
• 2003.07b
• /
• pp.1392-1394
• /
• 2003

This paper presents the actual test data of 3 phase, 9 pole, 3.6 [kw] synchronized wind-power generator controlled by hinged vane system and the possibilities of the small mount wind-power generations at the south-east coast of Ul-san. It also shows the data of the wind-velocity acquired by wind-direction sensor, calculation and analysis of the estimated electrical generation power, energy storage systems, and the efficient usages of the wind-power system.

• Proceedings of the KIEE Conference
• /
• 1993.07a
• /
• pp.271-273
• /
• 1993

One maglev vehicle is composed of 6 or 8 modules. Each module is composed of 4 staggered magnets attached to an aluminum bogie. In the view point of levitation control except propulsion-by LIM. 5 is the maximum degree of freedom to be controlled. But rolling control of the vhhicle depends on the bogie structure. We describe just anti-roll type bogie structure and 4 degree of freedom control is sufficient for levitation quality improvement. Multivariable pole-placement concept is used for controller design. Control experiment is performed on a specially designed test module as well as actual bogie system.

• Proceedings of the KIEE Conference
• /
• 2009.04b
• /
• pp.136-138
• /
• 2009

A new class of electronically commutated brushless motor, the flux-switching motor(FSM) is gradually emerging in power tools and household appliances especially fan application. This motor offers advantages of both high-power density and relatively high efficiency This paper presents the principle of the FSM and design of the 12/6 pole FSM drive system. Finally, test results of the prototype motor are provided to verify a validity of the fan application.

• Journal of Electrical Engineering and Technology
• /
• v.9 no.5
• /
• pp.1577-1581
• /
• 2014

This paper presents a method to minimize torque ripple of a V-type IPMSM using the PSO (Particle Swarm Optimization) method with FEM. The proposed algorithm includes one objective function and three design variables for a notch on the surface of a rotor. The simulation model of the V-type IPMSM has 3-phases, 8-poles and 48 slots with 2 notches on the one-pole rotor surface. The arc-angle, length and width of the notch are optimized to minimize the torque ripple of the motor. The cogging torque of the model is reduced by 55.6% and the torque ripple is decreased by 15.5 %. Also, the efficiency of the motor is increased by 15.5 %.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.52 no.4
• /
• pp.154-154
• /
• 2003

The switched reluctance motor(SRM) has a considerable potential for industrial applications because of its high reliability as a result of the absence of rotor windings. In some applications with SRM, a parallel switching strategy is often used for cost saving, increasing of current capacity and system reliability. This paper proposes a new parallel switching strategy of SRM using parallel winding. While conventional parallel switching devices are connected in a phase winding, power devices are connected in the parallel windings wound in each pole of stator in the proposed method. Paralleling strategy for current sharing in the proposed method can be easily determined without considerations of any nonlinear characteristics of power devices such as conduction resistance, threshold voltage and gain factor. The proposed paralleling strategy is verified by the mathematical analysis and experimental results.

• Proceedings of the KIEE Conference
• /
• 2005.07b
• /
• pp.1264-1266
• /
• 2005

This paper analyzes static and transient response characteristics of a permanent magnet type stepping motor with claw poles using three-dimensional finite element method. The outer diameter of the stepping motor to be analyzed is approximately 6 mm. In this paper we analyzes only 2 poles of the stepping motor, which has 10 magnetic poles made up of NdFeB material, using periodic boundary condition. We clarify transient response and static torque charateristics using Maxwell 3D and Matlab Simulink.

• Proceedings of the KIEE Conference
• /
• 1998.11a
• /
• pp.3-6
• /
• 1998

In this paper, we evaluated the effect the tooth shape influenced against the thrust force which then was confirmed by experimentation. We analyzed the effect of by measuring static thrust force of the Phases of A and B. With this result, we found that there is an area where the thrust force abruptly decreases because the variance of the airgap permeance is very small following the positions of the stator and the mover. And the unbalance among phases showed almost equal, which means that static thrust force of the phases of A and B is very small because magnetic path of the 2-phase 8-pole HB-type is almost equal.

• Transactions of Materials Processing
• /
• v.7 no.6
• /
• pp.610-619
• /
• 1998

The superplastic blow forming technology has advantages of cost reduction and low material consumption. compared to the conventional sheet metal forming technology due to the capability of precisely forming with high elongation and low flow stress. however it has a disadvantage that its partial thickness distribution is non-uniform. A processing technology like diaphragm forming has been developed even though it is difficult to prepare materials for superplastic blow forming. in this study a hemisphere forming of sheet before superplastic forming. It was found that the rotary forming material was less in quantity of cavitation at pole than that of hemisphere part that was superplastic formed without rotary forming treatment. Also discussed are the critical strain which is closely related to cavity shape and size.

• Journal of the Korean Mathematical Society
• /
• v.56 no.6
• /
• pp.1463-1474
• /
• 2019

Let C be a nonsingular projective curve of genus ${\geq}2$ over an algebraically closed field of characteristic 0. For a point P in C, the Weierstrass semigroup H(P) is defined as the set of non-negative integers n for which there exists a rational function f on C such that the order of the pole of f at P is equal to n, and f is regular away from P. A point P in C is referred to as a weak Galois-Weierstrass point if P is a Weierstrass point and there exists a Galois morphism ${\varphi}:C{\rightarrow}{\mathbb{p}}^1$ such that P is a total ramification point of ${\varphi}$. In this paper, we investigate the number of weak Galois-Weierstrass points of which the Weierstrass semigroups are generated by two positive integers.