• Progress in Superconductivity and Cryogenics
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• v.14 no.3
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• pp.43-47
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• 2012

A linear compressor generates pulsating pressure and oscillating flow in a cryocooler such as Stirling cryocooler and pulse tube refrigerator. It is driven by AC power source and designed to operate at resonance of piston motion. The driving voltage level is determined by electric parameters of resistance, inductance and thrust constant of linear motor. From voltage equation on linear motor, the power factor of driving power is inherently less than 1. The phase difference between voltage and current of supplied power can be zero using capacitor and this can minimize a supply voltage level. Especially, the linear compressor of kW class requires high voltage and thus can cause a difficulty in selecting power supply unit due to limitation of voltage level. The capacitor in driving electric circuit is useful to settle this problem. In this study, the electric circuit of linear compressor is analytically investigated with assumption of mechanical resonance. The electric parameters of commercial linear motor are used in the analysis. The effects of capacitor on driving voltage level and power factor are investigated. From analytic results, it is shown that the voltage level can be mimized with using capacitor in driving electric circuit.

• Journal of the Korean Institute of Telematics and Electronics
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• v.8 no.2
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• pp.24-33
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• 1971

A noble method of delta modulation by means of pair transistor circuit having negative resistance charcteristic is presented. An RC parallel circuit is inserted between two eiuitter tarminals of the pair transistor circuit, and their emitters are driven by a square pulsed current source. Basically this is a relaxation oscillator circuit. But when the value of capacitors and resistanc R, and the pulse height of driving source are properly chosen, the RC parallel circuit apparently functions as integrating circuit of driviving pulses. Compared with the integrated voltage of capacitor C, a signal input voltatage supplied in series with RC parallel circuit between two emitters makes on or off either of the pair transistors. as the result, one bit pulse is sent out from the coupling resistance terminal of conducted transistor. The circuit diagram used for this experiment is presented, it i% composed with simple mod ulster circuit, differential amplifier and pulse shaping amplifier, The characteristics of the components of this ciruit are discussed, and especially quantumized noise in this delta modulation system is discussed in order to improve the signal to noise ratio which has a close relation with circut constants, quantumized voltage, pulse height and width of driving current source.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.38 no.4
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• pp.45-53
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• 2001

We have proposed a new driving method of AC PDP for both high resolution over HDTV and high luminance. The new driving method can reduce data and scan pulse width to 0.85${\mu}s$ by utilizing both rising and falling edges of sustain pulse and can provide high resolution AC PDP with high luminance by increasing the number of addressing discharge using sustain pulses with phase shifts. As a result, the proposed driving scheme makes it possible to drive 2080 horizontal resolution panel with high luminance. The experimental results using 4-inch color AC PDP with $30{\times}58$ pixels indicate that the luminance can achieved up to 850 $cd/m^2$ without image noise when we employ the four phase shifted sustain pulses with the amplitude of 140V and the frequency of 125KHz.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.514-517
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• 1996

Zero current switching(ZCS) series resonant converter is used to control laser power density in a pulsed Nd:YAG laser power supply. The high power and high repetition rate paused Nd:YAG laser is designed and fabricated to control current pulse width and pulse repetition rate in the double elliptical laser oscillator. In order to find out operational characteristics of pulsed Nd:YAG laser, the electrical properties of driving power supply and laser output power are investigated and experimented by changing of the current pulse width from 200uS to 350uS(step 50uS) and pulse repetition rate range of 500pps(pulse per second) to 1150pps. From that result, we obtaind maximum efficiency of 1.83% and maximum laser output or 220W at the condition of 350 uS and 1150pps with one Nd:YAG rod), and obtained that of more than 400W with two laser head connecting series.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.551-554
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• 1999

In this paper, we developed a radial pulse transducer that has strain-gauge cantilever type load cell for total pulse detection on chongu arterial. The transducer consist of load cell and driving electronic circuits. Load cell consist of cantilever and two metal film strain gauge. The Pressure signal from chongu artery is delivered to load cell using artery rider that attached to cantilever Therefore the pressure signal convert to voltage signals by the developed transducer As the results of experiment, the developed transducer has very good linearity at pressure to voltage conversion. The total pulse detection transducer can detected three kinds of chongu artery pulse with conveniently.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.6
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• pp.981-987
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• 2017

In this paper, we describe the LPM structure with a two-phase, which is not used previously, and explain its operation principle. In order to predict the accurate performance of LPM reduction model, finite element model was derived and the back EMF of LPM reduction model was measured and compared. In order to investigate the thrust and normal force of the LPM reduction model, a driving circuit capable of applying two-phase pulse currents was constructed and the performance was predicted in conjunction with the finite element analysis model. Finally, the design considering actual LPM size was performed. Since the size of the reduction model is small, the field could be made of a permanent magnet. However, it is almost impossible to manufacture a permanent magnet to match the size and capacity of a real LPM for a vehicle, in terms of cost and writing. Therefore, the actual vehicle LPM was replaced by wound type that generates a magnetic field by applying current to the field winding, and the final model was derived using the reaction surface method.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.521-527
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• 2005

In the past decades, complain about ground vibration and noise induced by pile driving has been quickly increased. Because of that, auger drilled piling methods have frequently used specially in urban area. However, the present auger drilled piling methods induce inevitable ground disturbance as well as a certain degree of vibration and noise due to the final hammering. For these reasons, a new auger drilled piling method is required to be developed. This paper introduces PDT(Pulse Discharge Technology) piling method and presents the characteristics of bearing capacity. The PDT piling method is to install in-situ piles using electric power so called Pulse. The pile installed by PDT appears to be able to develop shaft and end bearing capacity efficiently.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.10
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• pp.634-640
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• 2004

In this paper, the control strategy for high speed operation in light rail transit system is proposed. Recently, the vector control strategy is used to get high capacity control characteristic in low speed area. But Six step mode that is one pulse mode is used in high speed region to use DC link voltage to the maximum. Therefore, in high speed area, the vector control can not be used but scalar control method is used. To get a driving performance to be stabilized, the method of smooth mode change between the low speed and high speed area and PWM control is desired. So this paper proposes the control strategy using vector control include the one pulse mode. And also proposes overmodulation method that makes to change in one pulse mode softly. The performance of traction system will be verified by simulation results using MATLAB and experimental results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.142-142
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• 2010

This research proposed an advanced Electronic bead (EB) using MMA (Methy methacrylate) and CCA (Charge Control Agent). In the first, this paper presents about measurement method and characterization analysis of EB and nano-silica with pulse waveform in aging. Furthermore; this work presents the positive and negative EB fabrication procedure. As the experimental results, the proposed EB with square waveform is very attractive to Electronic paper driving characterization.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.146-148
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• 2006

The aim of the paper is to design the PLS(Plasma Lighting System) driving inverter circuit with optimal efficiency. In general, it is known that the PLS driven by a pulse has a higher light-conversion efficiency. There are the Class-E type resonant inverter and the semi-bridge inverter as a circuit which can make a pulse with low duty ratio. In this paper, we analyze the losses of the above two circuits. To verify the loss analysis, the inverter circuit with 220V 380W input consumption is manufactured and tested. Throughout the experimental results, the high efficiency PLS system has confirmed.