• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.130-132
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• 1997

In this paper, we propose a new type of tubular linear induction motor(TLIM) with two-dimensional motion. The proposed motor consists of four short primary LIMs arranged on a same circumference and a common secondary. By adopting independently energized ring-windings to the primary, we can expect the reduction of coil-end region and the freedom of alternating current supply. The secondary conductor is capable of producing anyone of rotary, linear, and helical motions by controlling the phase of supply currents in each primary winding. From the 3-D finite element analysis and the experiment, we derive the feeding conditions to increase the subsidiary rotary-force and an optimal arrangement of primary currents to reduce the number of slot.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.6
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• pp.26-33
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• 2002

In this paper, a new four-quadrant MOS analog multiplier Is proposed using the quarter-square technique, which is based on the quadratic characteristics of MOS transistor operating in the saturation region and the difference operation of a source-coupled differential circuits. The proposed circuit has been fabricated in a p-well CMOS process. The multiplier achieves a total harmonic distortion of less than 1 percent for the both input ranges of 50 percent of power supply, a -3㏈ bandwidth of 30㎒ a dynamic range of 81㏈ and a power consumption of 40㎽. The active chip area is 0.54㎟. The supposed multiplier circuit is simple and adjust high frequency application because one input signal transfer output by one transistor.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.453-454
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• 2016

The ESS(Energy Storage System) connected with distributed generation is drawing attention due to improving the quality load leveling, peak shaving for enhancing reliability of the power grid. The grid-connected inverter makes frequency adjustment to the active power's charge discharge according to the load variation. In addition, the inverter is possible to act as a reactive power compensation device to eliminate harmonic operates as power factor change inhibiting, anti-transient voltage fluctuation, active filter. In this paper, we propose a design method of igbt stack considering the reactive power supply capacity to improve the quality and reliability of the inverter. Moreover, the grid-connected inverter considering the four-quadrant rated operation designed stack and verified the feasibility of the design through a thermal analysis.

• Proceedings of the KOR-KST Conference
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• 1999.10a
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• pp.155-160
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• 1999

이 연구는 도로상의 신호사거리에서 신호변환시 발생하는 혼돈지역의 개념을 이용하여 도로-철도 교차로에 설치되는 사각차단기의 운영시간을 결정하는 방법론을 제시한다. 이 방법론은 현재 미국 일리노이주에서 시카고-세인트루이스의 고속전철 노선중 6개의 교차로에 설치중인 사각차단기의 운영시간을 설정하여 제시함으로써 현장검증이 되었다. 특히, 운전자가 교차로 진입시 차단기 사이에 차량이 걸리지 않으며 혹은 정지시 안전하게 교차로 앞에서 정지하도록 하는 의사결정이 이루어 지도록 최적의 차단기 운영시간을 운전자에게 제시하였다.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.69-71
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• 2003

Switched reluctance machine has much attention because of high efficiency, high power and DC series torque characteristics with a traction drive. But the motor has to have a regenerative mode when it is adopted in an electric vehicle. A current divergence during the regeneration makes difficulties in the control of SRM. This paper proposes a reference current limitation strategy for a stable regeneration based on simulations and experimental tests. The motor is operated with conventional current limit and switching angle control method in motoring mode. Simulations and experiments are executed to verify proposed method.

• Proceedings of the KIPE Conference
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• 2001.12a
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• pp.41-45
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• 2001

This paper presents an implementation of motion control system of Switched Reluctance Motor (SRM) using digital hysteresis controller by TMS320F240 DSP. SRM position control system possess several advantages over other motors, including high efficiency, simple structure, low cost, and four-quadrant operation at a wide speed range, especially for the servo drive systems with precision, stability and fast response characteristics in the industrial applications. In the suggested motion control system, position control using digital hysteresis controller is developed, and is evaluated using experimental testing. The developed system for cost reduction and high-performance by fully digital controller is shown a good response characteristic of motion control results.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.630-633
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• 1997

This paper describes a design of a single phase PWM converter for high speed train. Parallel operation and control method of four Quadrant PWM converters are described. Simulation and modelling of the converters is performed. Capacity of the converter/inverter and power circuit for high speed traction system designed. And harmonic contents of AC line current's are analyzed. The results of the simulation are presented.

• Journal of Electrical Engineering and information Science
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• v.1 no.1
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• pp.51-57
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• 1996

An improved predictive current control technique for a zero current switched(ZCS) buck-boost series resonant inverter(SRI) is proposed to overcome the inherent disadvantages such as the uncontrollable large overshoot and the large current ripple. Using the proposed technique, four quadrant operations of the output voltage and current for an uninterrutible power supply(URS) application are guaranteed and the buck-boost operation can also be obtained without an additional bidirectional switch.

• The Journal of the Korea Contents Association
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• v.20 no.12
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• pp.287-300
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• 2020

The present study applied the IPA(Importance-Performance Analysis) to derive several practical alternatives for the improvement of Chuncheon Silver Orchestra program using IPA(importance-performance analysis). Most importantly, this work performed a comparative study using sample data collected from two groups of silver member(N=53) and program operator(N=32). A careful literature review leaded to the development of six types of evaluation sectors, including 'connection with the local community', 'budget operation', 'program operation', 'manpower operation', 'public relations strategy' as well as 'environment for program operation'. This work further devised twenty-two evaluation items. The results indicated that silver member group rated 'manpower operation' the highest in their both perceived importance and performance. Program operator group rated 'budget operation' and 'manpower operation' rated the highest in their perceived importance and performance, respectively. The results form IPA matrix analysis provides an important implication that much efforts and interests should be sustainably given from the perspective of the silver member group and the program operator group coupled with four types of IPA quadrant, accordingly.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.268-270
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• 1995

In crane drives, DC motor has been most widely used due to simple control characteristic and favorable transient behavior. Nowadays, however, the squirrel cage induction motor is known as an attractive candidate due to elimination of all sliding electrical contacts, resulting in an exceedingly simple and rugged construction. Especially, in hoist application, the smooth torque control and four quadrant operation are essential. In this paper, an operation of dual inverters with common DC bus fed by vector controlled induction motor is described. Single DSP is employed as a main processor to control dual inverters and communicates each input/output signal with PLC. As well as giving a detailed expression, full simulation and experimental results are presented.