• The Transactions of the Korean Institute of Electrical Engineers P
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• v.53 no.3
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• pp.116-121
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• 2004

This paper proposes a novel UPFC based on 3-level Half-bridge modules, isolated through single-phase multi-winding transformers. The dynamic performance of proposed system was analyzed by simulation with EMTDC, assuming that the UPFC is connected with the 138-kV transmission line of one-machine-infinite-bus power system. The proposed system can be directly connected to the transmission line without series injection transformers. It has flexibility in expanding the operation voltage by increasing the number of 3-level Half-bridge modules.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.147-149
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• 1998

In this paper, zero voltage switched half bridge converter and an active-clamped, zero voltage switched forward converter equipped with self-driven synchronous rectifier is designed and investigated for high efficiency BC-DC converter. A synchronous rectifier is has a lower conduction power loss than shottky diode rectifier. The purpose of this paper is to investigate the effect of parasitic inductance in a synchronous rectifier of DC-DC converters and examine overall efficiency of zero voltage switched DC-DC converters.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.341-342
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• 2010

본 논문에서는 종전의 3상 H-브리지 PWM 인버터와 다른 토폴로지를 갖는 3상 벅-부스트 DC-AC 인버터를 위한 제어 기법을 제안하였다. 이를 위하여 공간벡터 변조 방식(SVM : Space Vector Modulation) 및 PI 제어기를 벅-부스터 DC-AC 인버터에 적용하고 이를 PSIM 시뮬레이션 통하여 타당성을 검증하였다.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.62-65
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• 2003

We considered of the efficiency for the Buck+Half bridge converter This converter has advantages of applications for a low output voltage, a high output current and a wide input voltage. Developed the Buck converter ratings and the Half Bridge converter ratings are 36$\~$72V Input and 22V/5A output, 19$\~$24v input and 3.3V/30A output, respectively. Buck converter is operated with zero voltage switching process to reduce the switching losses. The 80.1 $\~$97.6$\%$ of the efficiency is measured at 18.4 $\mu$H output filter inductance of Buck convertor. In Half Bridge convertor, the 86$\~$96.4$\%$ of the efficiency is measured at 100kHz switching frequency with PQI core.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.1
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• pp.105-111
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• 2010

This article studies the design of DC-DC Converter to convert low-voltage energy sources generated from renewable power like battery power, photovoltaic power, or fuel cells into high-voltage ones. The circuit topology of H-bridge Converter to convert input voltage, 24[V], into out voltage, 400[V], was realized through applying phase shift angle control so as to manage electric power and voltage in the output side. The advantages of the converter system suggested are the low cost as well as current stress reduction, high efficiency, reliability, and simplified maintenance. It is also found that the system is highly useful to produce residential electric power.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.1
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• pp.40-45
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• 2004

This paper presents the parallel distributed control scheme for shaping of the bent glass. The designed system consists of a PC, a main controller and 11 servo-controllers, the precision motion controllers. Each elements are connected by using RS-232C and 8-bit data bus. In order to guarantee the stability and the control performance, we use a precision PID motion controller and a H-bridge on the servo-drivers. PC calculates position values of 11 DC motors by using the pre-determined curvature value and offers the user interface environment operator. The main controller provides the control instructions and parameter values to 11 servo-controllers by chip enable signal, simultaneously. Using the received commands and parameter values, the servo-controllers control the positions of the DC motors based on PID control scheme.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.371-376
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• 2005

In this paper, a new a new full-bridge soft-switching phase shift PWM DC-DC Converter has been proposed, which is suitable for fuel cell based power generation system. The proposed converter has outstanding advantage over the conventional DC-DC converter with respect to high efficiency, high power density, and hish component utilization. In special. the proposed converter has predominant high boosting output voltage and high efficiency characteristics under the inherently severs low output voltage of the fuel cell through the overall load conditions. Moreover, the developed converter has been experimentally tested with the help of a fuel cell simulator, and can generate the V-I characteristics of proton exchange membrane(PEM) fuel cell, so that the performance of the proposed converter could be effectively examined and the validity of the converter could be verified.

• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.95-96
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• 2015

In this paper, a single-sourced PV PCS using the trinary asymmetric MLI with a single-ended pre-regulator is proposed. Trinary based asymmetric CHB inverters provide higher output levels for the same number of cells compared to other CHB inverters. However, there is an issue of regeneration with trinary asymmetric inverters and this complicates the system with requirement of bi-directional converters at the input. Modified commutation strategies have been used to remove the regeneration issue with compromise in THD. The single-ended pre-regulator provides the isolated dc-link voltage for the individual H-bridge cells with the advantage of having a single switch and magnetic component. This implementation increases the magnetic utilization of the inductor core and reduces the switching loss in the pre-regulator and also the reduced parts count contributes to the cost competiveness of the proposed PCS. The proposed PV PCS has been verified using simulation results in this paper.

• Journal of Sensor Science and Technology
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• v.10 no.5
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• pp.304-313
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• 2001

In this research, we investigate wet-etching properties of GaAs in $NH_4OH-H_2O_2-H_2O$, and develop the fabrication method of GaAs microstructures with rectangular cross section using (001) GaAs substrate. For obtaining wet-etching properties with respect to crystallographic orientation, the etch rates and cross-section etch profiles of (001) GaAs with 16 different compositions and the undercut rates with 5 different compositions are measured using $NH_4OH-H_2O_2-H_2O$ mixed solutions. From these experimental data, a new GaAs micromachining method in bulk (001) GaAs is proposed, and used to fabricate a released microbridges with a rectangular cross section. The developed GaAs micromachining method can be very useful for low-loss, highly-tunable capacitors for RF components and for integration with GaAs optical components.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.5
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• pp.405-412
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• 1999

Meta! Halide Discharge(]\1HD) Iamps have good color rendition, long life and good focusing capability but h have flickers bv acoustic resonances. We have designed the electronic ballast for reducing acoustic resonances in high pressure discharge tube. The ballast consists of main two parts, the first part is a half-bridge inverter to make a square wave form a and the st'Cond part is a flyback converter to combine the low frequency and high frequency component. As a r result of this study, we conclude that MHD lamps of 70 watt 따c very well light(D without acoustic resonance p phenomena by the elestronic ballast.