• Title, Summary, Keyword: Resonant frequency

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High Frequency Dual Mode Control LLC Resonant Converter with Wide Input Voltage Range (넓은 입력전압범위의 고주파수 구동 Dual mode control LLC 공진형 컨버터)

  • Joo, Hyung-Ik;Yang, Jung-Woo;Jo, Kang-Ta;Han, Sang-Kyoo;Sakong, Suk-Chin
    • The Transactions of the Korean Institute of Power Electronics
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    • v.21 no.2
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    • pp.102-110
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    • 2016
  • In this paper, a high-frequency dual mode control LLC resonant converter with wide input voltage range is proposed through zero voltage switching (ZVS) under the universal line input voltage and every load conditions. Conventional small power adapter driving should be satisfied with universal line input voltage because it has no power factor correction circuit regulation. The conventional LLC resonant converter for an adapter can reduce the size of transformer in terms of high-frequency driving and ZVS. However, this converter has a disadvantage in terms of design of resonant tank under various input voltages because the frequency modulation range is very wide to satisfy voltage conversion gain. Compared with the conventional one, the proposed LLC converter can be adapted to universal line input voltage and high-frequency driving because it is controlled by pulse width modulation and pulse frequency modulation with control voltage. The validity of the proposed LLC converter is proved through the 60 W prototype.

Frequency Follow-up Control System of Resonant Load MOSFET Inverter using PLL (PLL을 이용한 공진부하 MOSFET 인버어터의 주파수 추종제어계)

  • Kim, Joon-Hong;Joong-Hwan kim
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.35 no.7
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    • pp.272-277
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    • 1986
  • The system that follows to the resonance frequency of high frequency MOSFET inverter and varies according to the changes of load characteristics is proposed. Also we suggested a method how to select the resonant load type between series and parallel circuit for a given inverter type. It leads to the conclusion that in the case of high impedance loads, parallel resonant circuits are preferable, on the other hand, for low impedance loads, series resonant circuits are more preferable. For frequency tracking, a PLL circuit is used as main control element to detect the phase difference of current and voltage of load. The realized apparatus composed of control circuit and voltage type full-bridged MOSFET elements as main parts of inverter. A stable frequency follow-up characteristics are obtained for 1.2MHz, 1.5KW high frequency output and power is always supplied to the load with unity power factor.

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Resonant Frequency Modulation of High Temperature Superconductors Subjected to Optical Pulse Energy and Temperature (광학 펄스 에너지와 온도 변화에 의한 고온 초전도체의 공명 진동수 변조)

  • Cho, Shin-Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.11
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    • pp.1061-1067
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    • 2005
  • The resonant frequency modulation of $YBa_2Cu_3O_{7-x}$ meander lines has been investigated as functions of optical pulse energy and temperature by using a network analyzer. The frequency-domain measurements are performed by controlling both the resonant frequency and the frequency width. The meander lines, configured in a microstrip geometry, are illuminated by optical pulses from an actively mode-locked Nd:YAG laser. The variation of the resonant frequency shows a quadratic dependence on the reduced optical pulse energy $P/P_c$, where $P_c$ is defined as the critical optical pulse energy at which resonance signal has disappeared. As for the dependence on temperature, the results are in good agreement with the previously reported data.

A Study on the Design of the Class E Resonant Rectifier with a Series Capacitor (직력 캐패시터를 가진 E급 공진형 정류기 설계에 관한 연구)

  • 김남호
    • Journal of the Korean Society of Marine Engineering
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    • v.22 no.3
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    • pp.343-352
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    • 1998
  • Higher frequency of energy transfer or at least energy conversion has to be used in order to reduce the size of inductors and capacitors required in the power supplies. Conventional PWM switching-mode power supplies have a limitation of operating frequency due to switching losses in the switching transistors and rectifier diodes. Means of reducing switching losses have been developed for high-frequency resonant amplifiers or more exactly dc/ac inverters. Because of smooth current and voltage waveforms resonant convertesrs havelower device switching losses and stresses lower electromagnetic interference(EMI) and lower noise than PWM converters. Therefore in this paper design equations of Classs E resonant low dv/dt rectifier with a series resonant capacitor drived using Fourier series techniques. The theory is compared with simulation results obtained for the rectifier operating at 10[MHz] ac input and 5[V] coutput.

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Frequency Agile Air-Gap Microstrip Antennas using PZT (주파수 조정이 가능한 PZT Air-Gap Antenna)

  • 우형관;하용만;오승재;송준태
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.772-775
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    • 2001
  • This paper investigated that resonant frequencies of microstrip patch antenna were frequency aigle when PZT were used as the antenna substrates. The resonant frequencies of the antenna using the piezoelectric substrate were able to be controlled by applied voltage. The frequency variation of the air gap antenna was 16MHz when the voltage variation was 12[KV/cm].

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Development of Automatic Firmness Measurement System for Major Fruits using Vibration Characteristics (과일의 진동특성을 이용한 주파수 영역에서의 경도측정)

  • 전종서;김중규
    • Proceedings of the IEEK Conference
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    • pp.253-256
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    • 2001
  • Characteristics of fruit vibrations are related to the material properties of the fruit. A new method for spectral analysis is developed and used for the non-destructive estimation of fruit firmness. The resonant frequency of the fruit is related to its firmness. However, the determination of the resonant frequency is not easy So the smoothing method is applied to the frequency spectra to obtain a robust estimate for the resonant frequency.

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A Study on Frequency Shift of Piezo Microstrip Antennas (피에조 마이크로스트립 안테나의 주파수 이동에 관한 연구)

  • Kang, Hyunil;Joung, Yeun-Ho;Hwang, Hyun Suk;Lim, Yun-Sik;Yu, Young Sik;Song, Woochang;Lee, Jongsung
    • Journal of Satellite, Information and Communications
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    • v.7 no.3
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    • pp.22-25
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    • 2012
  • In this paper, we proposed a method of the resonant frequency shift of a microstrip patch antenna using $LiNbO_3$, PVDF and FR-4 substrates. We designed and analyzed from these parametars optimized using Ensemble V 7.0 of the simulation tool. We observed the resonant frequency by DC appled electric field in a microstrip patch antenna. When $LiNbO_3$ substrate were applied from -300 to 300 V/mm, we obtained the resonant frequency shift of maximum 29 MHz. The microstrip patch antenna with PVDF (poly vinylidene fluoride) substrate, we obtained the resonant frequency shift of maximum 17 MHz at frequency 6 GHz. but when Epoxy FR-4 substrates used, the resonant frequency does not changed. This results showed the resonant frequency shift without physical strains in a microstrip patch antenna.

Characteristic Estimation of Single-Stage Active-Clamp Type High Frequency Resonant Inverter (단일 전력단 능동 클램프형 고주파 공진 인버터의 특성 평가)

  • 원재선;강진욱;김동희
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.53 no.2
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    • pp.114-122
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    • 2004
  • This paper presents a novel single-stage active-clamp type high frequency resonant inverter. The proposed topology is integrated full-bridge boost rectifier as power factor corrector and active-clamp type high frequency resonant inverter into a single-stage. The input stage of the full-bridge boost rectifier works in discontinuous conduction mode(DCM) with constant duty cycle and variable switching frequency. So that a boost converter makes the line current follow naturally the sinusoidal line voltage waveform. By adding additional active-clamp circuit to conventional class-E high frequency resonant inverter, main switch of inverter part operates not only at Zero-Voltage-Switching mode but also reduces the switching voltage stress of main switch. Simulation results have demonstrated the feasibility of the proposed high frequency resonant inverter. Characteristics values based on characteristics estimation through circuit analysis is given as basis data in design procedure. Also, experimental results are presented to verify theoretical discussion. This proposed inverter will be able to be practically used as a power supply in the fields of induction heating applications, fluorescent lamp and DC-DC converter etc.

Nondestructive Test of Optical Connector by Resonant Ultrasound Spectroscopy Method (공명초음파분광법에 의한 광컨넥터용 결합소자의 비파괴검사)

  • Kim, Sung-Hoon;Lee, Kil-Sung;Kim, Dong-Sik;Kim, Young-Nam;Jeong, Sang-Hwa;Yang, In-Young
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.6
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    • pp.143-150
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    • 2004
  • In this paper, resonant ultrasound spectroscopy(RUS) was used to determine the natural frequency of a ceramic ferrule and a ball lens. The ceramic ferrules are cylinderical shape with $\phi$ 2.56mm diameter and l0mm in length. Crack lengths of these ferrules are 10.40$\mu$m, 21.18$\mu$m and 32.35$\mu$m. The spherical ball lens was made of BK-7 glass, one's diameter in 2mm and 5mm. RUS system is consisted of spectrum analyzer, power amplifier, PZT sensor and support frame. The principle of RUS is that the mechanical resonant frequency of the materials depends on density and the coefficient of elasticity. Rus system is based on that given resonant frequency of the materials can be represented by the function of density and the coefficient of elasticity, and it is applied to excite specimen and to inspect the difference of natural frequency pattern between acceptable specimen and defective ones. Defect evaluation by RUS are performed to investigate the natural frequency measure of ferrule and ball lens.

A Contact-less Power Supply using LLC resonant converter for Photovoltaic Power Generation System (태양광 발전 시스템을 위한 LLC 직렬공진컨버터 적용 무접점 전원장치)

  • Lee, H.K.;Lee, G.S.;Kang, S.I.;Kong, Y.S.;Kim, E.S.;Kim, Y.H.
    • Proceedings of the KIEE Conference
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    • pp.347-350
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    • 2006
  • The high efficiency full-bridge LLC resonant converter using a contact-less transformer is proposed for the photovoltaic power generation system. For the series resonance with a series capacitor, the LLC resonant converter utilizes the leakage inductance and magnetizing inductance of a contact-less transformer. Unlike the conventional series resonant converter operated to the continuous resonant current at above resonance frequency, the proposed converter operates to the discontinuous resonant current at the narrow frequency control range below resonance frequency. Due to the discontinuous mode resonant current, the proposed converter can be achieved the zero voltage switching (ZVS) in the primary switches and the zero current switching (ZCS) in the secondary rectification diodes without any auxiliary circuit. In this paper, the experimental results of the proposed full-bridge LLC resonant converter using a contact-less transfonner are verified on the simulation based on the theoretical analysis and the 150W experimental prototype.

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