• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.7
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• pp.28-36
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• 2008

This paper presents a novel prototype of zero current switching pulse frequency modulation (ZCS-PFM )high frequency series resonant inverter using IGBT power module for electromagnetic induction eddy current heated roller in copy and printing machines. The operating principle and unique features of this voltage-fed half bridge inverter with two additional soft commutation inductor snubber are presented including the transformer modeling of induction heated rolling drum. This soft switching inverter can achieve stable zero current soft commutation under a discontinuous and continuous resonant load current for a widely specified power regulation processing. The experimental results and computer-aided analysis of this inverter are discussed from a practical point of view.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.7
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• pp.49-57
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• 2008

This paper presents a voltage source type half-bridge series resonant high frequency (HF) inverter for induction heated fixing roller in copy machines. This high-frequency inverter works under zero current soft switching (ZCS) commutation and has wide power regulation range due to employing a pulse density modulation (PDM) scheme. Transient and steady state operating modes of the inverter are presented in this paper together with its PDM-based power regulation system. Experimental operating performances of the developed HF-ZCS inverter as well as power losses and actual efficiency are discussed and compared with computer simulation results.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.6
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• pp.768-776
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• 2014

Using a simplified high-frequency small-signal equivalent circuit model for BSIM3 MOSFET, the fully differential two-stage folded-cascode CMOS operational amplifier is analyzed to obtain its small-signal voltage transfer function. As a result, the expressions for dc gain, five zero frequencies, five pole frequencies, unity-gain frequency, and phase margin are derived for op amp design using design equations. Then the analysis result is verified through the comparison with Spice simulations of both a high speed op amp and a low power op amp designed for the $0.13{\mu}m$ CMOS process.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.38-40
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• 2002

In the case of conventional high frequency inverter, with damage of switch by surge voltage when switch gets into compulsion extinction by load accident and so on because reactor is connected by series to switch, or there was problem of conduction loss by reactor's resistivity component, Also, it has controversial point of that can not ignore conduction loss of switch in complete work kind action of soft switching. In this paper, as high frequency induction heating power supply, we propose half bridge type multi resonance soft switching high frequency inverter topology that can realize high amplitude operation of load current with controlling switch current by multiplex resonance, mitigating surge voltage when switch gets into compulsion extinction and to be complete operation of zero current switching by opposit parallel connected reactor to inverter switch. and do circuit analysis for choice of most suitable circuit parameter of circuit

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.18-21
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• 1996

This paper deals with experimentation on static test of linear induction motor for the propulsion system of UTM(Urban Transit Maglev). It is very important that vertical force zero effects to levitation field of maglev. Because it is continuous for air gap 11mm of levitated maglev vehicle. Then we found the slip frequency that the vertical force zero due to it is variable. Thus we had compared between simulation value and experiment value for lim by static test Jig.

• Journal of KSNVE
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• v.10 no.5
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• pp.880-885
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• 2000

In a verical type, vibratory gyroscope, the coupled motion between the reference and sensing vibrations causes the zero-point output which means non-zero sensing vibration without angular velocity. This structural coupling leaks to an inherent discrepancy between the natural frequencies of the reference and sensing oscillations, causing the degradation of the sensing performance and dynamic stability. In this paper, the dynamic characteristics associated the coupling phenomenon are theoretically analyzed. Effects of reference frequency and coupling factor on the rotational direction and amplitude of elliptic oscillation are studied. A technique to predict the existence of curve veering of crossing in frequency trajectories is introduced to apply the design of micro gyroscopes with decoupled structures.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.4
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• pp.19-27
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• 2007

This paper presents a novel soft-switching PWM utility frequency AC to high frequency AC power conversion circuit incorporating boost H-bridge inverter topology, which is more suitable and acceptable for cost effective consumer induction heating applications. The operating principle and the operation modes are presented using the switch mode equivalent circuits and the operating voltage and current waveforms. The performances of this high-frequency inverter using the latest IGBTs are illustrated, which includes high frequency power regulation and actual efficiency characteristics based on zero voltage soft-switching(ZVS) operation ranges, and the power dissipation as compared with those of the conventional type high frequency inverter. In addition, a dual mode control scheme of this high frequency inverter based on asymmetrical pulse width modulation(PWM) and pulse density modulation(PDM) control scheme is discussed in this paper in order to extend the soft switching operation ranges and to improve the power conversion efficiency at the low power settings. The power converter practical effectiveness is substantially proved based on experimental results from practical design example.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2518-2521
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• 1999

A Full-bridge zero-voltage zero-current switching (ZVZCS) converter using transformer auxiliary winding is analyzed. A complete small-signal model for the control scheme is developed. The propoed model is accurate up to half the switching frequency. The dynamic characteristics are compared with those of the zero-voltage switching converter and buck converter. Model predictions are confirmed by experimental measurements.

• Journal of Power Electronics
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• v.11 no.1
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• pp.16-20
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• 2011

This paper presents a zero-voltage-switching (ZVS) boost converter using a coupled inductor. It utilizes an additional winding to the boost inductor and an auxiliary diode. The ZVS characteristic of the proposed converter reduces the switching losses of the active power switches and raises the power conversion efficiency. The principle of operation and a system analysis are presented. The theoretical analysis and performance of the proposed converter were verified with a 100W experimental prototype operating at a 107 kHz switching frequency.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1863-1866
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• 2002

This paper describes synthesis of a complex R$^{i}$ CR filter with a finite transmission zero except zero frequency. First, a new kernel function is proposed. Secondly, how to determine the element values included in the R$^{i}$ CR filter is described. A fifth-order R$^{i}$ CR filter is designed. Finally, the sensitivity property of the proposed filter is evaluated through computer simulation.