• Journal of the Microelectronics and Packaging Society
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• v.6 no.4
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• pp.49-53
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• 1999

In this study, the characteristics of the structure of buried type capacitor for RF multi- chip-module are investigated. We developed many kinds of structures to minimize the space of capacitor in module and the value of parastic series inductance without any loss in capacitance, and in this procedure the effect of vias especially position, size, number length are analyzed and optimized. This characteristics of structures are checked through HFSS(high frequency structure simulator) of HP, and the value of parastic series inductance is calculated by equivalent circuit analysis. And ensuing the result of simulation, we made buried type capacitors using LTCC (low temperature cofired ceramic) material. In measurement of this sample, we found out the effective and precise method can be applied to buried type and characteristics of vias and striplines added for measuring are quantified.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.5
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• pp.857-862
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• 2008

This paper evaluate the performance using a simulated 490KHz narrow band filter based on characteristic parameters appropriately extracted from 490KHz band-pass filter after considering each characteristic, which is modeled on equivalent circuit and applied to NAVTEX receiver using crystal oscillator. The evaluation results show that the value of a series capacitor of crystal oscillator has only little capacity by Cs=21.094fF and the bandwidth characteristics of filter go worse as the capacity value of crystal oscillator grow increase. Moreover, the series inductance value of crystal oscillator has a relatively big value by L=5H, therefore the bandwidth characteristic according as inductance's capacity shows more little effect than the capacity.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.128-137
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• 2015

A novel parallel three-level zero voltage switching (ZVS) DC converter is presented for medium voltage applications. The proposed converter includes three sub-circuits connected in parallel with the same power switches to share load current and reduce the current stress of passive components at the output side. Thus, the size of the output chokes is reduced and the switch counts in the proposed converter are less that in the conventional parallel three-level DC/DC converter. Each sub-circuit combines one half-bridge converter and one three-level converter. The transformer secondary windings of these two converters are connected in series in order to reduce the size of output inductor. Due to the three-level circuit topology, the voltage stress of power switches is equal to $V_{in}/2$. Based on the resonant behavior by the output capacitance of power switches and the leakage inductance (or external inductance) at the transition interval, each switch can be turned on under ZVS. Finally, experiments based on a 2 kW prototype are provided to verify the performance of the proposed converter.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.3
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• pp.81-87
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• 2015

In order to effectively protect electrical and electronic circuits which are extremely susceptible to lightning surges, multi-stage surge protection circuits are required. This paper presents the operational characteristics of the two-stage hybrid surge protection circuit in extra-low voltage DC power lines. The hybrid surge protective device consists of the gas discharge tube, transient voltage suppressor, and series inductor. The response characteristics of the proposed hybrid surge protective device to combination waves were investigated. As a result, the proposed two-stage surge protective device to combination wave provides the tight clamping level of less than 50V. The firing of the gas discharge tube to lightning surges depends on the de-coupling inductance and the rate-of-change of the current flowing through the transient voltage suppressor. The coordination between the upstream and downstream components of the hybrid surge protective device was satisfactorily achieved. The inductance of a de-coupler in surge protective circuits for low-voltage DC power lines, relative to a resistance, is sufficiently effective. The voltage drop and power loss due to the proposed surge protective device are ignored during normal operation of the systems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.2 s.93
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• pp.167-173
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• 2005

The isolation of the series PIN diode switch is restricted by the parallel capacitance of PIN diode and the switch driver circuit limits switching speed of PIN diode switch. To overcome these problems, a high isolation and high switching speed Pin diode switch is proposed adapting the parallel resonant inductance and TTL compatible switch driver circuit. The measurement results of the 3 GHz PM diode switch show 1 GHz frequency band, less than 1.5 dB insertion loss, 65 dB isolation, more than 15 dB return loss and less than 30 ns switching speed. In particular the 3 GHz PIN diode switch using the parallel resonant inductance exhibits the improvement of isolation by 15 dB.

• Journal of Power Electronics
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• v.14 no.3
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• pp.478-487
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• 2014

This study presents a new interleaved three-level zero-voltage switching (ZVS) converter for high-voltage and high-current applications. Two circuit cells are operated with interleaved pulse-width modulation in the proposed converter to reduce the current ripple at the input and output sides, as well as to decrease the current rating of output inductors for high-load-current applications. Each circuit cell includes one half-bridge converter and one three-level converter at the primary side. At the secondary side, the transformer windings of two converters are connected in series to reduce the size of the output inductor or switching current in the output capacitor. Based on the three-level circuit topology, the voltage stress of power switches is clamped at $V_{in}/2$. Thus, MOSFETs with 500 V voltage rating can be used at 800 V input voltage converters. The output capacitance of the power switch and the leakage inductance (or external inductance) are resonant at the transition interval. Therefore, power switches can be turned on under ZVS. Finally, experiments verify the effectiveness of the proposed converter.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.5
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• pp.27-34
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• 2004

In this paper, we designed the electronic ballast for the 400[W] hight pressure sodium lamp using the half-bridge inverter Inductance and capacitance in the proposed equivalent LC series resonant circuit are calculated theoretically. We performed the simulation of the LC series half-bridge inverter circuit using the IsSPICE and the electronic ballast for the high pressure sodium lamp were implemented for verifing the simulation results. In the experimental results, the specification of the implemented electronic ballast are almost same with the simulated one. The experimental results show the good performance as PF 99.3[%], $A_{THD}$ 10.01[%], lamp efficiency 119[lm/W] at the output 400[W].].

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.990-1001
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• 2015

This paper presents analysis of Switched Reluctance Machine (SRM) using Geometry Based Analytical Model (GBAM), Finite Element Analysis (FEA) and Fourier Series Model (FSM) with curve fitting technique. Further a Transient Analysis (TA) technique is proposed to corroborate the analysis. The main aim of this paper is to give in depth procedure in developing a Geometry Based Analytical Model of Switched Reluctance Machine which is very accurate and simple. The GBAM is developed for the specifications obtained from the manufacturer and magnetizing characteristic of the material used for the construction. Precise values of the parameters like Magneto Motive Force (MMF), flux linkage, inductance and torque are obtained for various rotor positions taking into account the Fringing Effect (FE). The FEA model is developed using MagNet7.1.1 for the same machine geometry used in GBAM and the results are compared with GBAM. Further another analytical model called Fourier Series Model is developed to justify the accuracy of the results obtained by the methods GBAM and FEA model. A prototype of microcontroller based SRM drive system is constructed for validating the analysis and the results are reported.

• Journal of Power Electronics
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• v.14 no.4
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• pp.661-670
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• 2014

A new DC/DC converter with zero voltage switching is proposed for applications with high input voltage and high load current. The proposed converter has two circuit modules that share load current and power rating. Interleaved pulse-width modulation (PWM) is adopted to generate switch control signals. Thus, ripple currents are reduced at the input and output sides. For high-voltage applications, each circuit module includes two half-bridge legs that are connected in series to reduce switch voltage rating to $V_{in}/2$. These legs are controlled with the use of asymmetric PWM. To reduce the current rating of rectifier diodes and share load current for high-load-current applications, two center-tapped rectifiers are adopted in each circuit module. The primary windings of two transformers are connected in series at the high voltage side to balance output inductor currents. Two series capacitors are adopted at the AC terminals of the two half-bridge legs to balance the two input capacitor voltages. The resonant behavior of the inductance and capacitance at the transition interval enable MOSFETs to be switched on under zero voltage switching. The circuit configuration, system characteristics, and design are discussed in detail. Experiments based on a laboratory prototype are conducted to verify the effectiveness of the proposed converter.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.1
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• pp.23-30
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• 2014

This paper proposes a single power-conversion ac-dc converter with a dc-link capacitor-less and high power factor. The proposed converter is derived by integrating a full-bridge diode rectifier and a series-resonant active-clamp dc-dc converter. To obtain a high power factor without a power factor correction circuit, this paper proposes a suitable control algorithm for the proposed converter. The proposed converter provides single power-conversion by using the proposed control algorithm for both power factor correction and output control. Also, the active-clamp circuit clamps the surge voltage of switches and recycles the energy stored in the leakage inductance of the transformer. Moreover, it provides zero-voltage turn-on switching of the switches. Also, a series-resonant circuit of the output-voltage doubler removes the reverse-recovery problem of the output diodes. The proposed converter provides maximum power factor of 0.995 and maximum efficiency of 95.1% at the full-load. The operation principle of the converter is analyzed and verified. Experimental results for a 400W ac-dc converter at a constant switching frequency of 50kHz are obtained to show the performance of the proposed converter.