• Title, Summary, Keyword: Resonant frequency

Search Result 2,191, Processing Time 0.042 seconds

The Analysis of a Series Resonant Converter with Frequency Control (주파수 제어에 의한 직렬 공진형 컨버터의 특성 해석)

  • 이윤종;김철진
    • The Transactions of the Korean Institute of Electrical Engineers
    • /
    • v.39 no.6
    • /
    • pp.557-567
    • /
    • 1990
  • This paper describes the static and dynamic characteristic analysis of the Series Resonant DC to DC Converter with frequency control. The natural commutation of all switch element is realized when the switching frequency is below the resonant frequency of the tank circuit, and the analysis is limited to only this region. For the analysis method, state plane technique is adopted, and each operation mode is defined from normalized switching frequency Fsn. Under this condition, circuit performance is analyzed ideally. The physical characteristics of the series resonant converter is easily grasped by this analysis method with frequency control and this analytical results are directly applicable to the actual converter design. The validity of the analysis is verified by comparing with experimental results and the stability of the converter is confirmed against small variations around the operating point by conventional frequency domain analysis.

  • PDF

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

  • ;;;A. Egawa;H. Muramatsu
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
    • /
    • /
    • pp.183-188
    • /
    • 1998
  • A quartz crystal analyzer is utilized to monitor the cmsion process of an aluminum surface of a quartz crystal by sea water. A quartz crystal having 2000${\AA}$ of aluminum layer is installed in a spedally designed cell and is in contact with an 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 spectrornetedEDX). 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 metal surface.

  • PDF

High Switching Frequency and High Power Density Three-Level LLC Resonant Converter using Integrated Magnetics (Integrated Magnetics를 적용한 고속 스위칭 및 고전력밀도 3 레벨 LLC 공진형 컨버터)

  • Nam, Kyung-Hoon;Park, Chul-Wan;Bae, Ji-Hun;Ji, Sang-Keun;Ryu, Dong-Kyun;Choi, Heung-Gyoon;Han, Sang-Kyoo
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.22 no.6
    • /
    • pp.551-554
    • /
    • 2017
  • This paper proposes a three-level LLC resonant converter using integrated magnetics (IM). Given that the switch voltage stress of the proposed converter is guaranteed to be half of the input voltage, the switching losses can be greatly reduced, thereby benefitting the high-frequency operation. To reduce the volume of reactive components such as transformers, high-frequency driving and planar core are applied. However, two resonant inductors and one transformer are required because of the three-level structure and the limited leakage inductance of the planar transformer for the resonant operation. Therefore, the effect of volume reduction is not very large. In order to solve these drawbacks, this paper proposes a new IM that integrates all magnetic elements used in the proposed three-level resonant converter by using the magnetizing inductor as a resonant inductor. The experimental results are presented by conducting a theoretical analysis of a prototype with 350 W to 800 kHz.

A Study on Efficiency Improvement of Resonant Inverters (공진형 인버터의 효율 향상에 관한 연구)

  • Cho, Kyu-Min;You, Wan-Sik;Kim, Nam-Jeung;Kim, Hee-Jun
    • Proceedings of the KIEE Conference
    • /
    • /
    • pp.409-411
    • /
    • 1999
  • Usually, in many applications. high frequency resonant inverters are used and the ZVS(Zero Voltage Switching) or ZCS(Zero Current Switching) techniques are used to improve the efficiency of resonant inverters. In this paper, a new switching scheme is proposed to improve the efficiency of resonant inverters which is based on the plan to keep the unity output displacement factor under the variable resonant frequency. The detail algorithm of the proposed switching sheme and the simulation results are presented.

  • PDF

Temperature Stability of Length-Extensional Vibration Modes in PZT Ceramics (PZT세라믹스에 있어서 길이진동모드의 온도안정성)

  • 이개명;현덕수
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.14 no.9
    • /
    • pp.726-730
    • /
    • 2001
  • Temperature stabilities of dielectric constraints and resonant frequencies of the substrates are very important in piezoelectric ceramics oscillators and filters. In this study, it was investigated temperature stability of the length-extensional vibration mode of Pb(Zr$\_$y/Ti$\_$1-y/)O$_3$+x[wt%]Cr$_2$O$_3$ ceramics. The mode can be utilized in fabricating ultra-small 455 kHz IF devices. Addition of Cr$_2$O$_3$ in morphotrophic phase PZT decreased the variations of dielectric constant, electro-mechanical coupling factor k$\_$31/ and resonant frequency by thermal shock. As additive weight of Cr$_2$O$_3$increased, the temperature coefficient of resonant frequency changed from positive number to negative one. And the composition tith temperature coefficient of resonant frequency was shifted to the one with increased Cr$_2$O$_3$ additive weigh by thermal aging.

  • PDF

Characteristic analysis of the resonant current injection type high frequency resonant inverter using ZVS (ZVS를 이용한 공진전류 주입형 고주파 공진 인버터의 특성해석)

  • Won, Jae-Sun;Kim, Hae-Jun;Cho, Gyu-Pan;Kim, Dong-Hee;Bae, Young-Ho;Min, Byung-Jae
    • Proceedings of the KIEE Conference
    • /
    • /
    • pp.1038-1040
    • /
    • 2001
  • A half-bridge type resonant current injection type high frequency resonant inverter using ZVS(Zero-Voltage-Switching) used as power source of induction heating at high frequency is presented in this paper. This proposed inverter can reduce distribution of the switching current because of using the current of serial resonant circuit to the input current of the parallel one. The analysis of the proposed circuit is generally described by using the normalized parameters, the principle of basic operating and the its characteristics are estimated by the parameters such as switching frequency and load resistance. According to the calculated characteristics value, this paper proves the validity of theoretical analysis through the Pspice.

  • PDF

Drive Characteristics Using Resonant Frequency of a Ring Type Ultrasonic Motor

  • Yoon, Shin-Yong;Baek, Soo-Hyun;Kim, Cherl-Jin
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
    • /
    • v.3B no.4
    • /
    • pp.173-178
    • /
    • 2003
  • The rotational force of ultrasonic motors is able to get from the frictional force of elliptical vibration by contact between rotor and stator. Generally, ultrasonic motors are suitable for driving at resonant frequencies of about 20∼80[KHz]. The driving characteristics of ring type ultrasonic motors are the object of this study. A two-phase driving signal is delivered to the tested ultrasonic motor, which has a $90^0$ phase difference respectively with both sine and cosine voltage waveforms. The driving frequency is almost equal to the mechanical resonant frequency for the proper operation, and the driving signal is supplied by the two-phase parallel resonant inverter. The validity of the proposed driving method is verified by experimental results with stable operation.

A Study on the Digital Control of Single Phase Induction Motor Driven by the Full Bridge Resonant Inverter(I) - The Current Characteristics of Full - bridge Resonant Inverter at Low Frequency - (전브리지 공진형 인버터에 의한 단상 유도전동기의 디지탈제어에 관한 연구(I) -저주파수에서 전브리지 공진형 이버터의 전류특성에 대하여-)

  • 노영오;박진길
    • Journal of the Korean Society of Marine Engineering
    • /
    • v.17 no.3
    • /
    • pp.70-79
    • /
    • 1993
  • The application of A.C. motor to servo system is rapidly increased according to the recent advance of power electronics and digital control techniques. The induction motor which has a simple structure and needs less maintenance is used in the industrial field for the variable speed and position control recently. In this paper, the current characteristic of the full-bridge resonant inverter is studied by comparing with the computer simulation and the laboratory experiment when the ratio of forced frequency to the natural frequency and the ratio of conduction time to the period at the given frequency is changed. And then, the full-bridge resonant inverter is applied to the speed control of single phase induction motor.

  • PDF

Measurement of Liquid Density using Tuning Fork (튜닝포크를 이용한 액체밀도의 계측)

  • Kim, Choong-Hyun;Lee, Yong-Bok;Lee, Sung-Chul
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.16 no.1
    • /
    • pp.86-91
    • /
    • 2007
  • A sensor using quartz toning fork is presented for measuring liquid density. It consists of a PZT plate as an actuator for piezoelectric excitation and a quartz tuning fork as a sensor for resonant frequency detection. The resonant frequency is determined from the sensing voltage measured in tuning fork when the excitation frequencies of PZT actuator are swept around the resonant frequencies of tuning fork. The resonant frequency determined the liquid density. The density values of three kinds of organic solvents are measured and compared with the standard values. The experimental results are in agreement with the standard values and the maximum standard deviation is less than 9%.

Resonant Frequency Recovery of Resonator for Magnetic Resonant Wireless Power Transfer Inserted into Dielectric Material (유전체에 삽입된 자기공진형 무선전력전송 공진기의 공진주파수 복원에 관한 연구)

  • Kang, Seok Hyon;Jung, Chang Won
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.29 no.12
    • /
    • pp.992-995
    • /
    • 2018
  • The wireless charging of body-embedded medical instruments and wireless power transfer to various inside dielectric-materials is still a future technology that has not yet been achieved. This paper proposes methods for controlling the capacitance of the resonators and installing air pockets on the top and bottom sides of the resonators for optimal design, which considered efficiency and resonant frequency in accordance with the electromagnetic characteristics of the dielectric medium. In future, the results of this research will be utilized as the basic research data to design and restore resonant frequency of resonators embedded in various dielectric environments.