• Title/Summary/Keyword: Self-oscillation

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Design of the self-oscillation UV flash lamp power supply and the characteristic of its operation using self-resonance of the transformer (트랜스포머의 자가 공진(Self-Resonance)특성을 이용한 자가 발진(Self-Oscillation) UV(Ultra Violet) 발생 플래시램프 전원장치설계 및 그 동작 특성)

  • Kim, Shin-Hyo;Cho, Dae-Kweon
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.1
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    • pp.48-55
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    • 2014
  • These Xenon flashlamp power supply for Ultra Violet has converter with high voltage conversion ratio. General model is composed of transformer with high voltage conversion ratio and voltage doubler rectifier circuit. Purpose of power supply leads dielectric breakdown of Xenon flashlamp and passes current rapidly. When passing current, it has to limit current to avoid over-heat, damage of electrode and acceleration of gas oxidation which are cause of performance degradation of lamps. Generally, inductors and resistors, which are called as "Ballast," are used to limit currents. Generally, Transformer has high turn ratio to make high voltages. But we can get high voltages using the transformer with low turn ratio which is driven with self resonance. Also, an advantage of self resonance is to make a circuit simply through impedance of transformer in resonance frequency which filters output voltage. As using an unique impedance of transformer, the circuit does not need other impedance elements like the ballast. So the power supply assures high efficiency of the arc discharge.

PID Autotuning Based on Saturation Function Feedback with A Static Load Disturbance (정적 부하왜란이 있는 경우의 포화함수를 이용한 PID 자동동조)

  • Oh, Seung- Rohk
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.51 no.12
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    • pp.542-548
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    • 2002
  • We consider an unknown linear time invariant plan with static load disturbance. A saturation function nonlinear element is sued to find th one point information in the frequency domain. We analyze an asymmetric self-oscillation caused by static load disturbance with relay feedback and saturation function feedback. We propose a new method to tune a PID controller using a saturation nonlinear feedback element in the presence of asymmetric oscillation. The proposed method does not require the knowledge of plant d.c. gain with an asymmetric oscillation in the plat output.

Fabrication and Characteristics of DFB Laser with Absorption Grating (흡수격자를 갖는 DFB 레이저의 제작 및 특성)

  • 이형종
    • Proceedings of the Optical Society of Korea Conference
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    • 1990.02a
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    • pp.73-78
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    • 1990
  • 1.3${\mu}{\textrm}{m}$ DFB with absorption grating of 1.55${\mu}{\textrm}{m}$ InGaAsP layer was fabricated. This new type of DFB laser shows self-plusation for DC operation. At low level of injection the relation between the pulsation frequency and the injection current shows similar behavior with the relaxation oscillation of ordinary laser and at high level of injection the pulsation frequency decreases compared to the relaxation oscillation. Period doubling, period 3 and 4 were observed for AC modulation. In case of period doubling the waveform shows only one pulse within a period without any accompanying subsidiary pulses and the oscillation frequency was quite stable. The pulse widths as short as 58.5 ps was achieved with AC modulation. We propose the time division multiplexing application of this kind of DFB laser.

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Resonant Loop Design and Performance Test for a Torsional MEMS Accelerometer with Differential Pickoff

  • Sung, Sang-Kyung;Hyun, Chul;Lee, Jang-Gyu
    • International Journal of Control, Automation, and Systems
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    • v.5 no.1
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    • pp.35-42
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    • 2007
  • This paper presents an INS(Inertial Navigation System) grade, surface micro-machined differential resonant accelerometer(DRXL) manufactured by an epitaxially grown thick poly silicon process. The proposed DRXL system generates a differential digital output upon an applied acceleration, in which frequency transition is measured due to gap dependent electrical stiffness change. To facilitate the resonance dynamics of the electromechanical system, the micromachined DRXL device is packaged by using the wafer level vacuum sealing process. To test the DRXL performance, a nonlinear self-oscillation loop is designed based on the extended describing function technique. The oscillation loop is implemented using discrete electronic elements including precision charge amplifier and hard feedback nonlinearity. The performance test of the DRXL system shows that the sensitivity of the accelerometer is 24 Hz/g and its long term bias stability is about 2 mg($1{\sigma}$) with dynamic range of ${\sigma}70g$.

Frequency Response Compensation Technique for Capacitive Microresonator (용량형 마이크로 공진기의 주파수 응답 보상 기법)

  • Seo, Jin-Deok;Lim, Kyo-Muk;Ko, Hyoung-Ho
    • Journal of Sensor Science and Technology
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    • v.21 no.3
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    • pp.235-239
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    • 2012
  • This paper presents frequency response compensation technique, and a self-oscillation circuit for capacitive microresonator with the compensation technique using programmable capacitor array, to compensate for the frequency response distorted by parasitic capacitances, and to obtain stable oscillation condition. The parasitic capacitances between the actuation input port and capacitive output port distort the frequency response of the microresonator. The distorted non-ideal frequency response can be compensated using two programmable capacitor arrays, which are connected between anti-phased actuation input port and capacitive output port. The simulation model includes the whole microresonator system, which consists of mechanical structure, transimpedance amplifier with automatic gain control, actuation driver and compensation circuit. The compensation operation and oscillation output of the system is verified with the simulation results.

Novel Self-Excited DC-DC Converters (새로운 자려식 DC-DC 컨버터)

  • Lee, Soung-Ju;Ahn, Tae-Young
    • Proceedings of the KIEE Conference
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    • 1999.07f
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    • pp.2505-2507
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    • 1999
  • This paper presents novel self excited DC-DC converters such as Buck-boost type, Buck type and also non-inverting Buck-boost type. The proposed converters has the following advantages: simple topology, small number of circuit components, easy control methode. Therefore, these converters are suitable for the portable appliances with battery source. Theoretical analysis and experimental results for SOW class Buck-boost type self oscillation DC-DC converter have been obtained, which demonstrate the high efficiency and good performance.

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A Study on Self-excitations in Laminar Coflow Jet Flames (층류 동축류 제트화염에서의 화염진동에 관한 실험적 연구)

  • Yoon, Sung Hwan;Park, Jeong;Yun, Jin Han;Keel, San In;Kwon, Oh Boong
    • 한국연소학회:학술대회논문집
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    • 2012.04a
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    • pp.83-85
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    • 2012
  • Experimental study in coflow jet flames has been conducted to investigate the effects of adding $N_2$, $CO_2$ and He to coflowing air-side in self-excitations. Differences in the behaviors between buoyancy-driven and diffusive-thermal self-excitations with similar frequency range are explored and discussed in laminar coflow jet flames.

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Combustion Stability Rating Test under Low Pressure Condition of a 75-tonf-class LRE Thrust Chamber (75톤급 액체로켓엔진 연소기의 저압 조건에서 수행된 연소안정성 시험)

  • Lee, Kwang-Jin;Kang, Dong-Hyuk;Kim, Mun-Ki;Ahn, Kyu-Bok;Han, Yeoung-Min;Choi, Hwan-Seok
    • Journal of the Korean Society of Propulsion Engineers
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    • v.14 no.5
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    • pp.92-100
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    • 2010
  • Combustion stability rating tests of 75-tonf-class thrust chamber for technology demonstration were carried out at a low pressure. Two kinds of mixing heads were used in this study. One of them has injectors of 631 and the other has injectors of 721. Mixing head with injectors of 631 showed a self-oscillation instability at the chamber pressure of 30 bar. Mixing head with injectors of 721 showed that a high frequency combustion stability was maintained under the same pressure and the same mass flow rate. But mixing head with injectors of 721 generated a self-oscillation instability at the chamber pressure of 20 bar and it was found that stability boundary region was changed due to the configuration of a mixing head from these results.

A Study on the Design of Self-oscillating Ballast for Electrodeless Lamp (무전극등 자려식 안정기 설계 연구)

  • Han, Soo-Bin;Park, Suck-In;Jeoung, Hak-Guen;Jung, Bong-Man;You, Seong-Won
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2004.11a
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    • pp.175-178
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    • 2004
  • Power supply technique for electrodeless lamps, especially self-oscillation method, is presented in this paper for Endura of Osram. The power supply uses different method for high efficiency at high frequency operation compared to the conventional method using saturable transformer. Exact parameter tuning using simulation is suggested for effective design for real applications.

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