• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.509-512
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• 2000

LCD displays for flat monitors the backlit using Cold Cathode Flourescent Lamps(CCFLs) In this paper a low-cost series resonant half-bridge inverter for LCD backlight is proposed as a CCFL ballast. It is regulated by asymmetric control for its fixed frequency soft switching model. The attractiveness of this topology is primarily its low cost because of using BJT switches and reduction of anti-parallel diode. Design procedure and experimental verification from 5W 15"LCD backlight are presented.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.110-113
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• 1999

본 연구에서는 고주파 유도가열을 위한 전원장치에 사용되는 인버터 시스템의 대용량, 고조파화를 실현하기 위한 고주파화 기술을 제안하였다. 부한 공진 인버터는 H형 전-브리지(Full-Bridge)로 구성하고 각 암당 IBGT를 2병렬로 조합하여 구성하고 부하는 직병열 공진회로로 구성한다. 스위칭 동작은 8개의 IGBT중 각 ARM당 2개씩 순차 제어하여 고속 대용량의 고주파 전력을 출력시킨다. 또한 스위칭은 스위치 턴온·오프시에 스위칭 손실을 줄이기 위해 ZVS(Zero-Voltage Switching) 기법을 도입한다. 제어는 고정주파수 PWM(Pulse Width Modulation) 제어를 하여 전력변환 효율을 극대화한다.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.18-19
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• 2017

This paper shows the design of the high voltage capacitor charger which using a modified series parallel resonant converter. The used silicon carbide Metal-Oxide Semiconductor Field Effect Transistor (SiC MOSFET) is proper for the few hundred kHz of high switching frequency to overcome the bulk resonant inductor and snubber capacitors. Furthermore, to increase the amount of the charging current, three phase delta transformer is used as well as the secondary sides are connected in parallel. In this paper, the design procedure of the high voltage capacitor charger is suggested and the output power is verified by the experimental results with the rated resistor load.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.9
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• pp.904-911
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• 2011

This paper deals with transmission characteristics of a new dual resonant structure for designing waveguide band-pass filter. The structure which has a pass-band between two adjacent stop-bands in a single body consists of circular ridged aperture and four armed conducting patch. The dual resonant behavior of the structure can be represented by a combination of LC series and parallel resonant circuits. Also these resonant properties can be easily controlled by varying the geometry of the aperture and four armed conducting patch. Actually, the structure is fabricated on the microstrip substrate by use of etching technique so that it is formed an iris type resonator which can be easily put into the transverse plane of the waveguide. We use WR-90 standard waveguide, adapters, and VNA(vector network analyzer) to measure the resonant characteristics of the structure. It is very useful to design and to improve the cutoff skirts characteristics in the waveguide band-pass filter design area.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.238-242
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• 2004

The paper describes an automatic frequency control current-fed inverter for forging applications. The IGBT in series with diodes as its switching devices in the inverter circuit which is of full-bridge type. The operating frequency is automatically tracked to maintain a small constant leading phase angle when load parameters change. The load voltage is controlled to protect the switches. The output power can be adjusted by varying the input current from phase controlled rectifiers which is a part of current source. The system has been operated at 15-17 kHz. The output power transferred to the load is 1,595 watts. It can heat the steel work pieces with 15 mm diameter and 120 mm long from room temperature to approximately 1100 $^{\circ}C$ within 20 seconds with 0.97 leading power factor on the input side.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.531-537
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• 2007

This paper presents a new method for determining L, Cs, and Cp in a series parallel resonant inverter. This inverter is suitable for driving high-intensity discharge (HID) lamps. The operating frequency is selected to avoid acoustic resonances which are governed by the size and shape of the arc tube. L, Cs and Cp, are chosen to satisfy the ignition and steady state requirements of the lamp. Equations are developed to analyze the starting condition and steady state operating condition of the lamp. For the prototype ballast for a 250W Metal Halide Lamp, experimental results are presented in order to validate the proposed method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.328.2-328
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• 2002

General modeling of a resonant shunting damper has been made Iron piezoelectric sensor/actuator equation. It is found that an additional damping, which is augmented to a system, is generated by the shunt damping effect The transfer function of the tuned electrical absorber is derived for both series and parallel shunt circuit. The governing equations and associated boundary conditions are derived using Hamilton's Principle. The shunt voltage equation is also derived from the charge generated in PZT due to beam vibration. The frequency response function of the obtained mathematical model is compared with that of the tuned eledtrical absorber and experimental work. The vibration amplitude is reduced about 15 dB at targeted second mode frequency.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2100-2102
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• 1998

A full bridge double resonant type inverter using Phasor shift suitable for heating magnetic and nonmagnetic at high frequency is described. A series-parallel arrangement of capacitor is adopted and optimum mode of operation is proposed. Also, Based on the characteristics value, a method of circuit design is proposed.

• Proceedings of the KIEE Conference
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• summer
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• pp.1211-1213
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• 2004

CCFL(cold cathode fluorescent lamp) are used to backlight of LCD(liquid crystal display). CCFL dimming methods are used to pulse frequency modulation(PFM) or pulse width modulation(PWM). In this paper, design of CCFL driving and control circuit by half-bridge type series and parallel resonant inverter that variable frequency modulation method to control the output voltage current. Inverter switching frequency is higher than resonant frequency for stable operating, and it is possible dimming control. On the basis of equivalent circuit, the validity of this study is confirmed by the comparison of simulation and experimental result.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.847-849
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• 1993

Two new schemes of three-phase rectifier using softing switching methods are introduced for the input power factor correction. These three-phase rectifiers are employed the zero voltage switching for the parallel resonant and zero current switching for the series resonant AC link type rectifiers. The dynamic modeling and discontinuous integral cycle mode control technique are also presented. With the proposed circuits and control technique, the high power factor can be obtained.