• 전기의세계
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• v.17 no.4
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• pp.7-12
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• 1968

In recent years the development of the SCR has made possible the control of the power system. It is one example that the speed control of the induction motor can be done by changing the frequency with the S.C.R. This paper is devoted primarily to a study of the running characteristics of the single phase induction motor through the experimental and theoretical methods when the speed of the motor is controlled by varying the conduction period in current with S.C.R. under the constant frequency. We conclude from the experiments that the adjustment of the phase angle in current is equivalent to the change of the supply voltage to the motor. Therefore, the speed control of the motor such as a fan duty motor is possibly by this methods.

• 전기의세계
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• v.31 no.3
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• pp.197-203
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• 1982

The effects on the characteristics of 20-W fluorescent lamp were studied when applying magnetic field to its positive column. First, when the direction of the magnetic field is axial, i.e., along the lamp, if the magnitude of the field is stronger than the critical field, lamp voltage is increased, lamp current decreased, luminous flux increased, starting voltage decreased, as increasing the applied magnetic field. At the magnetic flux density is 130 gauss, luminous flux is increased to about 6 percents and starting voltage is increased to about 45 percents. Second, when the direction of the magnetic field is transverse to the lamp axis, as increasing the applied magnetic field, lamp voltage is increased, lamp current decreased, luminous flux increased and starting voltage is nearly constant, but the rates of increase or decrease of this case is different from those of the first. At the magnetic flux density is 300 gauss, luminous flux is increased about 45 percents. In both cases, electric power dissipated by lamps is the same as that of the lamp which magnetic field is not applied to.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.5
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• pp.474-482
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• 1992

This paper describes the speed control system of an induction type ac servomotor drive on the vector control basis of slip frequency and constant secondary flux control for a quick torque response. The system is composed of a digital controller using a SCB-V50 microprocessor and a PWM inverter with power MOSFETs for high speed switching. And, for the measurement of actual instantaneous currents, MDCS A070-051 hall sensors are employed. The rising time of step responce by this system through the test of a 600[W] ac servomotor is 30[ms]. Overall experimental result shows that the drive performance of the system is similar to that of a separately excited armature current control of a dc motior.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2526-2528
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• 2001

본 논문은 Full bridge 방식의 LC 병렬구조를 갖는 400watt HID용 전자식 안정기 구조에 대한 해석과 항상 HID 램프가 일정한 출력을 갖도록 하는 제어 방법에 대해 다루었다. 전자식 안정기의 구조는 LC 병렬구조이다. 램프에 흐르는 전류값에 따라서 전자식 안정기의 동작주파수가 가변되는 구조를 가지고 있어, 램프 점등 초기에는 동작 주파수가 높다가 안정상태로 들어가면 주파수가 떨어지는 특성을 지니고 있다.

• Smart Structures and Systems
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• v.21 no.3
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• pp.335-347
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• 2018

The fast-growing number of mobile and wearable applications has driven several innovations in small-scale electret-based energy harvesting due to the compatibility with standard microfabrication processes and the ability to generate electrical energy from ambient vibrations. However, the current modeling methods used to design these small scale transducers or microgenerators are applicable only for constant-speed rotations and small sinusoidal translations, while in practice, large amplitude sinusoidal vibrations can happen. Therefore, in this paper, we formulate an analytical model for electret-based microgenerators under general sinusoidal excitations. The proposed model is validated using finite element modeling combined with numerical simulation approaches presented in the literature. The new model demonstrates a good agreement in estimating both the output voltage and power of the microgenerator. This new model provides useful insights into the microgenerator operating mechanism and design trade-offs, and therefore, can be utilized in the design and performance optimization of these small structures.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.2
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• pp.102-109
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• 1997

The width of fuzzy membership function and control rule has an effect on performance of the fuzzy controller for electric equipment systems. In this paper, the neuro-fuzzy controller is proposed to im¬prove the performance of fuzzy controller. It has the width of membership function, that is adapted to the electrical parameter using multi-layer neural network, it is applied to first order electric power system with dead time and various plant constant. The related simulation resolts show that the pro¬posed neuro fuzzy controller are superior characteristics of improved performance

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.42-48
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• 2010

The Microsource has to supply high quality Power that has high reliability and high energy efficiency to Load according to operating type of Microgrid. The energy sources of microsource type have various dynamic characteristic and transient response corresponding to classes and application skill. This paper shows dynamic characteristic of Microgrid according to Energy Source of microsource type. This research has been carried out by detailed modelling of Microturbine system and Fuelcell system. All models are realized by EMTP/RV and simulated change of operating type and load increase within Microgrid of DC constant voltage inverter model and Microturbine, Fuelcell based Microsource.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.312-315
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• 2001

Water-Electrolyzed gas is a mixed gas of the constant volume ratio 2:1 Hydrogen and Oxygen gained from electrolyzed water, and it has better characteristics in the field of economy, efficiency of energy, and environmental intimacy than acetylene gas and LPG used for existing gas welding equipment. So studies of Water-Electrolyzed gas are activity in progress nowadays, and commercially used as a source of thermal energy for gas welding in the industry. The object of this paper is V-I feature of Hydrogen -Oxygen Gas Generator using DC source

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.05a
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• pp.123-126
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• 1994

We discussed the thermal analysis for recording media with the variation of the laser pulse duration and the power and the temperature distribution for the optimized Te-based antireflection structure by using the computer calculations. If the radial diffusion of heat is negligible, we can calculate the maximum temperature at the spot center in recording layer by Simple Method, and the temperature profile considering the specific heat and the latent heat by Numerical Method. As a result, the effect of the heat sinking which acted as a loss for the hole formation can be minimized by introducing the pulse of the hole formation duration( $\tau$ ) shorter than the thermal time constant( $\tau$$\sub$D/) of dielectric layer. This requirments can be satisfied as using the dielectric thickness of the 7nd ART condition or the dielectric materials with low thermal diffusivity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.571-574
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• 2000

In this study, Tin oxide thin film for secondary battery was deposited on Pt/Ti/Si(100). It was fabricated by r.f. reactive sputtering with Tin metal target. At constant power (130W), pressure (Base 5$\times$10$^{-6}$ Torr, working 5$\times$10$^{-3}$ Torr) and at room temperature, it was fabricated by Ar/O2 gas ratio. After deposition, we got AFM & SEM to investigated surface of thin films and had XRD to find crystalline of thin films. Charge/discharge characteristics were carried out in 1M LiPF$_{6}$ , EC:DMC = 1:1 liquid electrolyte using lithium metal at room temperature.