• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.51-54
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• 2003

지금까지 통상적으로 사용하고 있는 Plasma Lighting System(이하 PLS)의 마그네트론 구동용 고전압, 고전류 전원장치는 성층 철심 HVT를 이용한 방식을 적용하고 있다. 이 방식은 상용 주파수를 사용하므로, 승압트랜스포머나 배 전압용의 커패시터를 대형으로 하기 때문에 고중량, 저효율 및 출력의 한계성과 광출력에서 플리커현상 둥의 단점을 지닌다. 이의 해결책으로 최근 인버터 방식의 전원장치를 PLS에 적용 하고자 하는 연구가 활발하게 진행되고 있다. 설계한 PLS 마그네트론 구동을 위한 고전압, 고전류 전원장치는 기존의 스위칭 기술을 이용 낮은 스위칭 손실의 고속 스위칭을 통한 시스템의 소형, 경량화 및 고전력밀도를 가지도록 하였고 $\mu$-com을 이용하여 Micro-wave의 누설에 따른 사고를 방지하기 위하여 광 검출과 마그네트론 온도 검출 등의 시스템 보호 기능을 가지고 있으며, 고전압 출력을 고저 항으로 분압하고 PWM 제어기에 피드백하여 매우 안정된 출력 전압이 얻어지도록 하였다. 또한 출력 전류를 제한 할 수 있게 하여 광량 조절이 가능하도록 하였다.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.403-404
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• 2008

자원의 고갈과 각종 환경규제 및 정부의 전력거래 방침 등으로 인해 점점 발전소에서는 전력 계통에 대한 신뢰도 및 전기품질을 유지하기가 어려워지고있다. 발전소의 부하대별 주요 운전 설계값은 효율과 바로 직결되는 사항으로 각 부하별로 온도와 압력 등 운전설계값을 최적의 상태로 유지하는 것은 발전소 수명과 발전효율, 전력거래 등에 있어 중요한 요소들이다. 전력시장에 진입하는 발전소는 전력계통의 갑작스런 불안성 상황이나 전력거래소 요청시 경사변동폭, 출력변통율, 무효전력 출력, 자동발전제어, 주파수조절량 확보 등을 수행할 수 있어야 한다. 본 논문에서는 고급공정제어기를 이용하여 운전설계계값을 효과적으로 제어 하면서 기존의 제어로직보다 전력계통상에서 요구되는 발전기 출력을 최대한 신속히 제어하는 과정을 기술하였다. 우선 보일러 마스터와 터빈 마스터, 급수 마스터로 구성된 제어로직을 설계한 뒤 이들 마스터에 대한 발전기 출력, 주증기 압력, 기수분리기 출구온도 각각의 영향을 모델링 기법을 이용하여 적합한 모델을 구했다. 각각의 모델을 고급공정제어기에 적용하고 발전기 출력제어에 대한 기존의 발전소 응답보다 좀 더 효율적이고 실제적용이 가능한 결과를 얻을 수 있도록 튜닝을 시행했으며 그 과정과 결과를 기술했다.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.509-510
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• 2008

본 논문은 $0.18{\mu}m$ CMOS 공정을 사용하여 2.5Gb/s CMOS CDR을 설계하였다. CML type의 논리게이트를 이용하여 보다 높은 주파수의 대역의 데이터를 복원하기 위한 위상비교기(PD)와 PD의 up과 down신호를 지연없이 루프필터(LF)에 공급하기 위한 전하점프(CP) 그리고 외부 스위치를 통해 VCO이득을 조절할 수 있는 링 타입의 VCO로 구성되었다. 또한 VCO의 부담을 줄이기 위하여 half-rate 클럭 테크닉을 사용하였다. Cadence tool을 사용하여 모의실험 및 layout을 하였다. VCO이득은 100MHz/V이고, 클릭 jitter는 rising일 때 27ps, falling일 때 32ps로 우수한 결과를 얻을 수 있었다. 테스트칩 제작은 매그나침 $0.18{\um}$ CMOS 공정을 이용하였다. 칩 사이즈는 PAD를 포함하여 $850um{\times}750um$이다.

• Journal of Advanced Navigation Technology
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• v.14 no.1
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• pp.11-19
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• 2010

In this paper, H-plane filtering-horn antenna operating at millimeter frequency band is proposed with embedded filter and three-layered dielectric lens for frequency selection and maintenance of main beam direction, respectively. The waveguide-typed filter and H-plane sectoral horn antenna are replaced with considerably size-reduced PCB substrate-typed filtering antenna using via fences and several posts. The waveguide-typed filter and H-plane sectoral horn antenna were designed in air-filled waveguide and then combined into size-reduced PCB substrate. For the control of the thickness of dielectric lens, single and multi dielectric lens have been employed. As a result of antenna gain, 8 and 13.5 dBi have been obtained at 41.5 GHz, respectively, from the simulations of single and multi-lens antennas.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.52 no.1
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• pp.20-27
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• 2003

In this study, we designed and made Ultrasonic motor-digital multi controller(USM-DMC) using FPGA chip, A54SX72A made in Actel Corporation. By the minute, USM-DMC can adjust the frequency, duty ratio, and phase difference parameters of USM by digital input to be each 11bit from PC. Therefore, when we use this controller, it is possible to apply typical three parameters individually as well as multi-parameters simultaneously to control the speed and the torque. What is more, the strongest point is that it can trace frequency based on optimized frequency as compared with the phase difference because we can input optimized resonant frequency while in motoring. And we test the speed of USM with the adjustment of multi-parameters, the phase difference-frequency. As the result of the test, in the case of the multi-parameters of the phase difference and frequency, the speed characteristic is more linear and stable, and wider in the range of control than the single-parameter of the phase difference or the frequency.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.2
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• pp.46-51
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• 2000

The generation of the intensive ultrasonic waves depend mainly on the energy conversion efficiency depending on high frequency oscillation of the generator and the control performance of stable output depending on load variation, respectively. In this dissertation, a new configuration of ultrasonic generator is specially proposed and designed for improving both efficiency and stability. The generating frequency is turned by a PLL. which is controlled through the detection on phase difference between outputs and currents of the loads and the output amplitude of MOSFET, Q1 are controlled by their products through the multiplier, which results in the control of the amplitude of voltage controlled oscillation. And finally, the proposed and designed ultrasonic generator is composed by the combination of the function in mentioned above. the analysis results of the proposed circuit shows a good agreement between simulations and experiments.

• Journal of Sensor Science and Technology
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• v.7 no.5
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• pp.342-349
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• 1998

A multipurpose TLD readout system for radiation dosimetry and thermoluminescence study is constructed and its characteristics are investigated. The thermoluminescent lights are measured by a PM tube and the current-to-frequency converter. TLDs are heated by platinum heater and the heating rate is linearly varied. Measurement of the glow curve and control of the whole system have been done by a personal computer equipped with an interface board. The automatic gain control can be done by the control software. The lower detection limit of the system is about $10\;{\mu}Gy$ and dose response is linear.

• Journal of the Korean Institute of Gas
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• v.13 no.1
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• pp.9-13
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• 2009

A cause of noise and vibration which come from a Combustion of gas heater are a combustion roar and Combustion oscillation. A character of a combustion roar is that sound pressure is distribute with broad band frequency. otherwise, The presence of combustion oscillation caused by positive Feed Back in Combustion Chamber break out a noise and vibration. Accordingly, The method that be solved a noise and vibration is to make each natural frequency different frequency. first, in order to solve problem, we control ratio of fuel and air. that is, Keep away resonance. second, in order to changing natural frequency of Combustion Chamber, We changed the shape of Economizer.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.942-948
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• 2011

Solid propulsion systems have simple structures compared to other propulsion systems and are suitable for long-term storage. However the systems generally have limits on control of thrust levels. In this paper we introduce controllers for combustion chamber pressure using on-off control techniques which have been known for relatively easy implementation and energy efficiency. For this, we use a simple pressure change model by considering only mass conservation within the combustion chamber and we design a classical controllers and on-off controllers with are Pulse Width Modulation(PWM) and Pulse Width Pulse Frequency Modulation (PWPFM). Then we compare the performance results of the controllers through numerical simulations.

• The Journal of the Acoustical Society of Korea
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• v.15 no.6
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• pp.99-103
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• 1996

Most waveform coding techniques attempt to reduce redundancy of speech signal while preserving the shape of the waveform. In speech synthesis, wavefrom coding methods are used to the synthesis by rule for high quality speech. However, it is difficult to apply the waveform coding to the synthesis by rule because the parameters of the wavefrom coding cannot be classified as either the excitation or the vocal tract parameters. The proposed method shows little spectrum distortion of 2.7% or less for 50% pitch changes. It also achieves smooth connection of wavefrom magnitudes among the frames by compensating the phase in time domain.