• Journal of Power Electronics
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• v.12 no.3
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• pp.439-447
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• 2012

In this paper, an input-series auxiliary power supply scheme is proposed, which is suitable for high input voltage and multiple-output applications. The power supply scheme is based on a two-transistor forward topology, all of the series modules have a common duty ratio, all the switches are turned on and off simultaneously, and the whole circuit has a single power transformer. It does not require an additional controller but still achieves efficient input voltage sharing (IVS) for each series module through its inherent transformer-integration strategy. The IVS process of this power supply scheme is analyzed in detail and the design considerations for the related parameters are given. Finally, a 100W multiple-output auxiliary power supply prototype is built, and the experimental results verify the feasibility of the proposed scheme and the validity of the theoretical analysis.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.531-534
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• 2005

This paper presents a new data line sharing technique for TFT-LCD panels. This technique reduces the number of data driver IC's to half by having two adjacent pixels share the same data line. This in turn doubles the number of gate lines, which are integrated directly on the glass substrate of amorphous silicon for further cost reduction and more compactness. The proposed technique with new pixel array structure was applied to 15.4 inch WXGA TFT-LCD panels and has proven that the number of driver IC's were halved with nearly 41% circuit cost reduction and 5.3% reduction in power consumption without degrading the image quality.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.1
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• pp.14-17
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• 1996

We analyzed the characteristics of a power system with superconducting fault current limiter and showed the possibility of the application of a superconducting fault current limiter to a real power system through manufacturing of and experiment about 220Vrms/100Apeak class superconducting fault current limiter. We experimentally confirmed that the overvoltage of superconducting fault current limiter increased as the rate of current sharing to the limiting coil grew. The fault current could be limited within a few milliseconds when it was applied to a power system in series. Therefore, we could confirm that superconducting fault current limiter was effective in protection of a substation or power plant at short-circuit fault. (author). 7 refs., 7 figs., 2 tabs.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.274-276
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• 2007

In this paper, a low cost and high reliability control scheme is proposed for 400Hz UPS system operated in parallel. The proposed control scheme is consisted of two parts which are synchronization and load sharing control. The synchronization control is achieved by discrete logic ICs and analog circuit. The load sharing control is realized by current transformers (CTs) without any controller. Therefore, This proposed control scheme is rather simple and the cost may be decreased, compared with control scheme using expensive controller such as DSP and CAN. The practical feasibility of the proposed control scheme is proved by analysis and simulation.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.4
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• pp.335-342
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• 2016

This paper proposes an energy storage-assisted, series-connected module-integrated power conversion system that integrates a photovoltaic power conditioner and a charge balancing circuit. In conventional methods, a photovoltaic power conditioner and a cell-balancing circuit are needed for photovoltaic systems with energy storage devices, but they cause a complex configuration and high cost. Moreover, an imbalanced output voltage of the module-integrated converter for PV panels can be a result of partial shading. Partial shading can lead to the fault condition of the boost converter in shaded modules and high voltage stresses on the devices in other modules. To overcome these problems, a bidirectional buck-boost converter with an integrated magnetic device operating for a charge-balancing circuit is proposed. The proposed circuit has multiple secondary rectifiers with inductors sharing a single magnetic core, which works as an inductor for the main bidirectional charger/discharger of the energy storage. The secondary rectifiers operate as a cell-balancing circuit for both energy storage and the series-connected multiple outputs of the module-integrated converter. The operating principle of the cell-balancing power conversion circuit and the power stage design are presented and validated by PSIM simulation for analysis. A hardware prototype with equivalent photovoltaic modules is implemented for verification. The results verify that the modularized photovoltaic power conversion system in the output series with an energy storage successfully works with the proposed low-cost bidirectional buck-boost converter comprising a single magnetic device.

• Journal of Welding and Joining
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• v.9 no.3
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• pp.34-40
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• 1991

An automatic welding system was constructed with a personal computer to capture the welding data in addition to vision seam tracking for the gas metal arc welding process. The monitoring of welding signals is composed of the acquisition of welding voltage and current, obtained by using two differential amplifiers and A/D converters, and processing of the measured data. Using interrupt handing circuit for time sharing, two jobs of seam tracking and monitoring were performed at the required sampling time. Relations between welding signals and various welding circumstances were analyzed from the experimental results.

• Journal of Power Electronics
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• v.11 no.6
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• pp.779-786
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• 2011

This paper presents a soft switching converter to achieve the functions of zero voltage switching (ZVS) turn-on for the power switches and dc voltage step-up. Two circuit modules are connected in parallel in order to achieve load current sharing and to reduce the size of the transformer core. An active snubber is connected between two transformers in order to absorb the energy stored in the leakage and magnetizing inductances and to limit the voltage stresses across the switches. During the commutation stage of the two complementary switches, the output capacitance of the two switches and the leakage inductance of the transformers are resonant. Thus, the power switches can be turned on under ZVS. No output filter inductor is used in the proposed converter and the voltage stresses of the output diodes is clamped to the output voltage. The circuit configuration, the operation principles and the design considerations are presented. Finally, laboratory experiments with a 340W prototype, verifying the effectiveness of the proposed converter, are described.

• Proceedings of the KIPE Conference
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• 1996.06a
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• pp.89-92
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• 1996

This paper describes a detailed simulation model of the static condenser (STATCON) to analyze the dynamic interaction with the ac transmission line. The static condenser was represented by a 12-pulse voltage-source inverter sharing an energy storage dc capacitor. The voltage-source inverter consists of two 6-pulse bridges modeled with ideal gate-turn-off switches. The control system for the static condenser was designed through a mathematical model deduced from the equivalent circuit. Simulation results show that the conceived model is very effective to analyze the dynamic interaction between the static condenser and the ac transmission system.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.169-172
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• 2002

A protection integrated circuit which enables the stable operation of the rechargeable battery should be designed with a low-power architecture because it consumes the power of the battery. This paper proposed a low-power scheme especially when the several series-connected batteries are provided. By adopting a time sharing control of the batteries, the chip size and power consumption could be reduced.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1217-1220
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• 2003

A low-power design technique for lithium-ion Battery-Protection Integrated Circuit (BPIC) for multi cell configuration is proposed. The hardware sharing scheme with more precisely divided operating states in the detection range could reduce the power consumption significantly, especially during the normal state. The usefulness of the proposed scheme was confirmed through HSPICE simulations.