• Title, Summary, Keyword: Resonant frequency

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Nondestructive Evaluation of the Flaw in a Ceramic Ferrule by Resonant Ultrasound Spectroscopy (공명초음파분광법을 이용한 페롤의 비파괴결함평가)

  • 김성훈;백경윤;김영남;양인영
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.5
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    • pp.108-117
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    • 2004
  • In this paper, a measuring NDT(nondestructive testing) system using RUS(Resonant Ultrasound Spectroscopy) was built for nondestructive evaluation of the flaw in a ceramic Ferrule. The principle of RUS is that the mechanical resonant frequency of the materials depends on density, and the coefficient of elasticity. The RUS system is the measuring which is to exite specimen and to inspect the difference of natural frequency pattern between acceptable specimen and specimen which has some defects. RUS system is configured of spectrum analyzer, power amplifier, PZT sensor and support frame. For defect evaluation by the RUS, we performed to measure natural frequency of Ferrule, both acceptable and cracked. In the case of Ferrule, the resonant frequency of cracked-Ferrule existed to higher frequency band than acceptable-Ferrule.

A Novel Induction Heating Type Super Heated Vapor Steamer using Dual Mode Phase Shifted PWM Soft Switching High Frequency Inverter

  • Sugimura, Hisayuki;Eid, Ahmad;Lee, Hyun-Woo;Nakaoka, Mutsuo
    • Proceedings of the KIPE Conference
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    • pp.774-777
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    • 2005
  • In this paper, a constant frequency phase shifting PWM controlled voltage source full bridge-type series load resonant high-frequency inverter using the IGBT power modules is presented for innovative consumer electromagnetic induction heating applications such as a hot water producer, steamer and super heated steamer. The full bridge arm side link passive quasi-resonant capacitor snubbers in parallel with the each power semiconductor device and high frequency AC load side linked active edge inductive snubber-assisted series load resonant tank soft switching inverter with a constant frequency phase shifted PWM control scheme is discussed and evaluated on the basis of the simulation and experimental results. It is proved from a practical point of view that the series load resonant and edge resonant hybrid high-frequency soft switching PWM inverter topology, what is called class DE type. including the variable-power variable-frequency(VPVF) regulation function can expand zero voltage soft switching commutation range even under low output power setting ranges, which is more suitable and acceptable for induction heated dual packs fluid heater developed newly for consumer power utilizations. Furthermore, even in the lower output power regulation mode of this high-frequency load resonant tank high frequency inverter circuit it is verified that this inverter can achieve ZVS with the aid of the single auxiliary inductor snubber.

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Frequency and Amplitude Control of Micro Resonant Sensors (마이크로 공진형 센서의 주파수 및 진폭 제어)

  • Park, Sung-Su
    • Journal of Institute of Control, Robotics and Systems
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    • v.15 no.3
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    • pp.258-264
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    • 2009
  • This paper presents two control algorithms for the frequency and amplitude of the resonator of a micro sensor. One algorithm excites the resonator at its a priori unknown resonant frequency, and the other algorithm alters the resonator dynamics to place the resonant frequency at a fixed frequency, chosen by the designer. Both algorithms maintain a specified amplitude of oscillations. The control system behavior is analyzed using an averaging method, and a quantitative criterion is provided for the selecting the control gain to achieve stability. Tracking and estimation accuracy of the natural frequency under the presence of measurement noise is also analyzed. The proposed control algorithms are applied to the MEMS dual-mass gyroscope without mechanical connecting beam between two proof-masses. Simulation results show the effectiveness of the proposed control algorithms which guarantee the proof-masses of the gyroscope to move in opposite directions with the same resonant frequency and oscillation amplitude.

Corrosion of Quartz Crystal Marine Sensors in Sea Water (항만센서용 수정진동자의 해수에 의한 부식)

  • 최광재;장상목;김영한
    • Journal of Korean Port Research
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    • v.12 no.2
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    • pp.323-328
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    • 1998
  • A quartz crystal analyzer is utilized to monitor the corrosion process of an aluminum surface of a quartz crystal for marine sensor by sea water. A quartz crystal having 2000 $\AA$ of aluminum layer is installed in a specially designed cell and is in contact with sea water imitated electrolyte solution. While a constant potential is applied to the cell, the resonant frequency and resonant resistance are simultaneously measured using the quartz crystal analyzer. In addition, surface topographs are taken with an atomic force microscope(AFM) and the element analysis of the surface is conducted using an energy dispersive X-ray spectrometer(EDX). The simultaneous measurement of resonant frequency and resonant resistance during the corrosion process explains the change of surface structure caused by the corrosion. The variation of resonant frequency addresses the amount surface metal dissolution. As a conclusion, it is found that a simple measurement using the quartz crystal analyzer can replace the complex monitoring employing large equipments in the investigation of a corrosion process of sensor surface.

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Design and Resonant Characteristics of the Ultrasonic Sensor for Gas Flowmeter (기체유량계용 초음파 센서의 설계 및 공진 특성)

  • Hong, Jae-Il;Lee, Sang-Cheol
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.51 no.4
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    • pp.193-197
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    • 2002
  • In this paper, the ultrasonic sensor for gas flowmeter was simulated, fabricated and measured according to the assembly step and the piezoelectric vibrator layers. The simulated resonant frequency and the measured resonant frequency were similar except two layer sensor. The simulated resonant frequency of three layer sensor was 48 kHz and the measured resonant frequency of three layer sensor was 45.2 kHz. From the results, the ultrasonic sensor for gas flowmeter could be designed and expected without fabrication.

The Analysis of a High Frequency Series Resonant DC-DC Converter (고주파 직렬공진형 DC-DC Converter의 특성 해석)

  • 이윤종;김철진
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.39 no.9
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    • pp.934-943
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    • 1990
  • There are no turn-on losses in the series Resonant Converter which operates above the resonance frequency, and the commutation stress on the switched component is low. For a given Series Resonant Converter with specified load resistance, the output voltage is a function of the operation frequency. This paper describes the static and dynamic characteristic analysis of the Series Resonant DC to DC Converter, which is operating above the resonant frequency, with frequency control. For the analysis method, state plane technique is adopted, and the circuit operation is defined from normalized switching frequency, Fsn. Under this condition, circuit performance is analyzed ideally. The validity of the proposed analysis is verified by comparing with experimental results, the stability of the converter is confirmed against small variations around the operating point by conventional frequency domain analysis, and the stress quantity added to switch component is shown.

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Series Resonant ZCS- PFM DC-DC Converter using High Frequency Transformer Parasitic Inductive Components and Lossless Inductive Snubber for High Power Microwave Generator

  • Kwon, Soon-Kurl;Saha, Bishwajit;Mun, Sang-Pil;Nishimura, Kazunori;Nakaoka, Mutsuo
    • Journal of Power Electronics
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    • v.9 no.1
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    • pp.18-25
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    • 2009
  • Conventional series-resonant pulse frequency modulation controlled DC-DC high power converters with a high-frequency transformer link which is designed for driving the high power microwave generator has the problem of hard switching commutation at turn-on and turn-off of active power switching devices. This problem is due to the influence of the magnetizing current of the high-frequency transformer. This paper presents a novel prototype for a high-frequency transformer using parasitic parameters with a lossless inductive snubber and a series resonant capacitor assisted series-resonant zero current switching pulse frequency modulated DC-DC power converter, which is designed using a high power magnetron for microwave ovens. In order to implement a complete and efficient soft switching commutation, the performance of the new converter topology is practically confirmed and evaluated in the prototype of a power microwave generator.

Design, Fabrication, Static Test and Uncertainty Analysis of a Resonant Microaccelerometer Using Laterally-driven Electrostatic Microactuator (수평구동형 정전 액추에이터를 이용한 금속형 공진가속도계의 설계, 제작, 정적시험 및 오차분석)

  • Seo, Yeong-Ho;Jo, Yeong-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.3
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    • pp.520-528
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    • 2001
  • This paper investigates a resonant microaccelerometer that measures acceleration using a built-in micromechanical resonator, whose resonant frequency is changed by the acceleration-induced axial force. A set of design equations for the resonant microaccelerometer has been developed, including analytic formulae for resonant frequency, sensitivity, nonlinearity and maximum stress. On this basis, the sizes of the accelerometer are designed for the sensitivity of 10$^3$Hz/g in the detection range of 5g, while satisfying the conditions for the maximum nonlinearity of 5%, the minimum shock endurance of 100g and the size constraints placed by microfabrication process. A set of the resonant accelerometers has been fabricated by the combined use of bulk-micromachining and surface-micromachining techniques. From a static test of the cantilever beam resonant accelerometer, a frequency shift of 860Hz has been measured for the proof-mass deflection of 4.3${\pm}$0.5$\mu\textrm{m}$; thereby resulting in the detection sensitivity of 1.10${\times}$10$^3$Hz/g. Uncertainty analysis of the resonant frequency output has been performed to identify important issues involved in the design, fabrication and testing of the resonant accelerometer.

Dual Mode Phase-Shifted ZVS-PWM Series Load Resonant High-Frequency Inverter for Induction Heating Super Heated Steamer

  • Hisayuki Sugimura;Hidekazu Muraoka;Tarek Ahmed;Srawouth Chandhaket;Eiji Hiraki;Mutsuo Nakaoka;Lee, Hyun-Woo
    • Journal of Power Electronics
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    • v.4 no.3
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    • pp.138-151
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    • 2004
  • In this paper, a constant frequency phase shifting PWM-controlled voltage source full bridge-type series load resonant high-frequency inverter using the $4^{th}$ generation IGBT power modules is presented for innovative consumer electromagnetic induction heating applications, such as a hot water producer, steamer and super heated steamer. The bridge arm side link passive capacitive snubbers in parallel with each power semiconductor device and AC load side linked active edge inductive snubber-assisted series load resonant tank soft switching inverter with a constant frequency phase shifted PWM control scheme is evaluated and discussed on the basis of the simulation and experimental results. It is proved from a practical point of view that the series load resonant and edge resonant hybrid high-frequency inverter topology, what is called, DE class type, including the variable-power variable-frequency regulation function can expand zero voltage soft switching commutation area even under low output power setting ranges, which is more suitable and acceptable for newly developed induction heated dual pack fluid heaters. Furthermore, even the lower output power regulation mode of this high-frequency load resonant tank inverter circuit is verified so that this inverter can achieve ZVS with the aid of the single auxiliary inductor snubber.

A Study on The PWM Control of Resonant Inverters (공진형 인버터의 PWM 제어에 관한 연구)

  • Shin, Jae-Hwa;Cho, Kyu-Min;Kim, Young-Seok
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.38 no.1
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    • pp.53-60
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    • 2001
  • In many applications of power electronics, high frequency resonant inverters are used, and the PAM(Pulse Amplitude Modulation), PFM(Pulse Frequency Modulation) or PWM(Pulse Width Modulation) techniques are used to control the output power of resonant inverters. And the resonant inverters have to control the output frequency for the reliable operation under the variable load conditions. In this paper, a new switching scheme is proposed as a PWM control of resonant inverters. With the proposed method, it can be obtained that optimum resonant frequency and unity output displacement factor under the variable resonant frequency adaptively. The detail algorithm or the proposed PWM switching scheme and its output characteristics are discussed. And the veridity of the proposed method is confirmed with the experimental results.

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