• Title, Summary, Keyword: Resonant frequency

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The Response Properties of Organic Gas for the Palmitic Acid LB films by the Effect of pH (pH변화에 대한 Palmitic Acid LB막의 유기가스 반응특성)

  • 강기호;김정명;장정수;권영수
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.317-319
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    • 2000
  • We fabricated the QCM with Langmuir-Blodgett(LB) film deposited at the different subphase pH and investigated the resonant frequency response by the injection of organic gas response. In the $\pi$-A isotherms, the monolayer on the air/water interface had different limiting area per molecule and showed more condensed status as increasing the subphase pH. When palmitic acid LB film was deposited on the QCM, the resonant frequency shift was proportional to the deposited layer and had more resonant frequency shift in the case of the higher pH range as expected. In the resonant frequency for the injection of organic gas, it has been improved in the case of LB film fabricated at the lower subphase pH range and dependant upon the molecular weight of organic gas.

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Bandwidth Improvement of a Multi-resonant Broadband Acoustic Transducer (다중 공진 광대역 음향변환기의 대역폭 개선)

  • Lee, Dae-Jae
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.50 no.5
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    • pp.605-615
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    • 2017
  • A multi-resonant broadband acoustic transducer with six Tonpilz elements operating at different resonant frequencies in a transducer assembly was fabricated, tested, and analyzed. A compensated transducer, modified by adding series inductance to the developed multi-resonant broadband transducer, was shown to provide improved bandwidth performance with a relatively more uniform frequency response compared with the uncompensated transducer. By controlling the series inductance, flat frequency response characteristics at two frequency bands were obtained over the range 38-52 kHz with 1.1 mH inductance and 50-60 kHz with 0.4 mH inductance. These results suggest that the operating frequency of the developed multi-resonant broadband transducer in a chirp echo sounder can be shifted to a different frequency band that is optimized according to the environment for more effective echo surveys of fishing grounds.

Design of Polycrystalline 3C-SiC Micro Beam Resonators with Corrugation

  • Chung, Gwiy-Sang;Nhan, Nguyen Duong The;Thach, Phan Duy
    • Transactions on Electrical and Electronic Materials
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    • v.9 no.5
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    • pp.193-197
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    • 2008
  • On the purpose of increasing resonant frequency without sacrificing quality factor as well as much decreasing dimensions, corrugated micro beam resonator based on polycrystalline 3C-SiC films is the applicable solution. In this work, appropriate corrugated structure is suggested to increase resonant frequency of resonators. Micro beam resonators based on 3C-SiC films which have a two-side corrugation along the length of beams were simulated by finite element method and compared to a same-size flat rectangular. With the dimension of 36x12x0.5 ${\mu}m^{3}$, the flat cantilever has resonant frequency of 746 kHz. Meanwhile, with this size but corrugation width of 6 ${\mu}m$ and depth of 0.4 ${\mu}m$, the corrugated cantilever reaches the resonant frequency at 1.252 MHz.

A Novel Switched Capacitor Lossless Inductors Quasi-Resonant Snubber Assisted ZCS PWM High Frequency Series Load Resonant Inverter

  • Fathy, Khairy;Kang, Tae-Kyung;Kwon, Soon-Kurl;Suh, Ki-Young;Lee, Hyun-Woo;Nakaoka, Mutsuo
    • Proceedings of the KIEE Conference
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    • pp.169-171
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    • 2005
  • In this paper, a novel type of auxiliary switched capacitor assisted edge resonant soft switching PWM series load resonant high frequency inverter with two auxiliary edge resonant lossless inductor snubbers is proposed for small consumer induction heating appliances. The operation principle of this high frequency inverter is described using the switching mode equivalent circuits. The practical effectiveness of the newly proposed soft switching inverter are discussed as compared with the conventional soft switching high frequency inverters based on simulation and experimental results from an application point of view.

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A Controllable LCL-T Resonant AC/DC Converter for High Frequency Power Distribution Systems

  • Zeng, Jun;Li, Xuesheng;Liu, Junfeng
    • Journal of Power Electronics
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    • v.15 no.4
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    • pp.876-885
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    • 2015
  • High frequency alternating current (HFAC) has been widely used in a wide range of power distribution systems (PDS) due to its superior performance. A high frequency AC/DC converter plays the role of converting HFAC voltage to DC voltage. In this paper, a new LCL-T resonant AC/DC converter has been proposed, and an easier control method based on input voltage comparison is presented, without the complicated calculation of the zero-crossing point. Both a low distortion and near-to-unity power factor can be achieved by the proposed resonant converter and control strategy. The operational principle and steady-state analysis are given for the proposed resonant converter. A simulation model and experimental prototype are implemented with an operation frequency of 25kHz and a rated power of 20W. The simulation and experimental results verify the accuracy of the analysis and the excellent performance of the proposed topology.

A Novel Quasi-Resonant Snubber-Assisted ZCS-PWM DC-DC Converter with High Frequency Link

  • Fathy, Khairy;Kwon, Soon-Kurl
    • Journal of Power Electronics
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    • v.7 no.2
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    • pp.124-131
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    • 2007
  • In this paper, a novel type of auxiliary switched capacitor assisted edge resonant soft switching PWM resonant DC-DC converter with two simple auxiliary commutation lossless inductor snubbers is presented. The operation principle of this converter is described using the switching mode equivalent circuits. This newly developed multi resonant DC-DC converter can regulate its DC output AC power under a principle of constant frequency edge-resonant soft switching commutation by an asymmetrical PWM duty cycle control scheme. The high frequency power regulation and actual power characteristics of the proposed soft switching PWM resonant DC-DC converter are evaluated and discussed. The operating performances of the newly proposed soft switching inverter are represented based on simulation results from an applications point of view.

Induction Heating Water Heater using Dual Mode Phase Shifted ZVS-PWM High Frequency Resonant Inverter (듀얼 모드 위상 시프트 ZVS PWM 제어 고주파 공진형 인버터를 이용한 IH 온수기)

  • Lee, Sang-Wook;Ryu, Yeoi-Joung;Woo, Kyung-Il;Park, Han-Seok
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.67 no.2
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    • pp.82-89
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    • 2018
  • This paper presents a novel prototype of dual mode control based phase shift ZVS PWM high frequency load resonant inverter with lossless snubber capacitors in addition to a single active auxiliary resonant snubber for electromagnetic induction heating(IH) foam metal based consumer fluid dual packs(DPA) heater. The operating principle in steady state and unique features of this voltage source soft switching high frequency inverter circuit topology are described in this paper. The lossless snubber and auxiliary active resonant snubber assisted constant frequency phase shift ZVS PWM high frequency load resonant inverter employing IGBT power modules actually is capable of achieving zero voltage soft commutation over a widely specified power regulation range from full power to low power. The steady state operating performances of this dual mode phase shift PWM series load resonant high frequency inverter are evaluated and discussed on the basis of simulation and experimental results for induction heated foam metal heater which is designed for compact and high efficient moving fluid heating appliance in the consumer pipeline systems.

Cost Effective Quasi-Resonant Soft Switching PWM High Frequency Inverter With Minimum Circuit Components for Consumer IH Cooker and Steamer

  • Sugimura, Hisayuki;Eid, Ahmad-M.;Nakaoka, M.;Lee, H.W.
    • Proceedings of the KIEE Conference
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    • pp.134-139
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    • 2005
  • This paper presents a cost effective quasi-resonant soft-switching PWM high frequency inverter with minimum circuit components. This inverter can achieve wider soft commutation, simpler power circuit configuration, smaller volumetric size, lower cost and wider power regulation range, higher-efficiency as compared with single ended quasi-resonant ZVS-PFM inverter and active voltage clamped quasi-resonant ZVS-PWM inverter. The operation principle of the proposed inverter is described on the basis of the simulation and experimental results, together with its operating performances in steady state. The operating performances of this unique proposed high frequency inverter based on ZVS and ZCS arms-related soft commutation principle is evaluated and discussed as compared with the active voltage-clamped ZVS-PWM inverter and a conventional single-ended ZVS-PFM inverter. The practical effectiveness of a novel type quasi-resonant soft-switching PWM high frequency inverter using IGBT is actually proved for consumer induction heated appliances as rice cooker, hot water producer, steamer and super heated steamer. The extended bidirectional circuit topology of quasi-resonant PWM high frequency inverter with minimum circuit components is demonstrated, which operate as the direct frequency changer.

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Analysis and Modelling of Vibration Performance for Multi-layered Corrugated Structure

  • Kim, Jin Nyul;Sim, Jae Min;Park, Min Jung;Kim, Ghi Seok;Kim, Jongsoon;Park, Jong Min
    • Journal of Biosystems Engineering
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    • v.38 no.4
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    • pp.327-334
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    • 2013
  • Purpose: The purpose of this study was to analyze for resonant frequency, vibration transmissibility and damping ratio of multi-layered corrugated structures using a random vibration test. Methods: The random vibration test was performed by the ASTM D4728 specifications using two paperboards (S120, K180) and two types of flutes (A/F, B/F). Damping ratio of the multi-layered corrugated structures was estimated using a theoretical equation derived from the measured resonant frequency and transmissibility. Results: The resonant frequency and vibration transmissibility of the multi-layered corrugated structures of K180 and B-flute were higher than those of S120 and A-flute, respectively; however, the damping ratio of each sample had the opposite tendency. The resonant frequency was inversely proportional to the sample thickness and static stress; vibration transmissibility and damping ratio were not correlated with sample thickness and static stress. In addition, we developed a mathematical model of the resonant frequency with variables of sample thickness and static stress. Conclusions: Results of this study can be useful for environment-friendly and optimal packaging design since vibration has been a key factor in cushioning packaging design.

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

  • 유완식;조규민
    • Proceedings of the IEEK Conference
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    • pp.17-20
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    • 2000
  • Usually, in many applications, 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. In this paper, a new switching scheme is proposed as a PWM control method. With the proposed method, it can be obtained that unity output displacement factor under the variable resonant frequency. The detail algorithm of the proposed PWM switching scheme and its charicteristics are discussed. And the validity of the proposed method is confirmed with the experimental results.

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