• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.2
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• pp.83-88
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• 1999

Series connection of power semiconductor devices is selected in high voltage and high power applications. It is important to prevent the overvoltage from being induced across a device above ratings by the proper voltage balancing in the field of IGBT series connection. In addition, the overvoltage induced by a stray inductance has to be limited in the high power circuit. This paper proposes a new gate control scheme which can balance the voltage properly and limit the overshoot by controlling the slope of collector voltage under the turn-off transient in the series connected IGBTs. The proposed gate control scheme changes the slope of collector voltage by sensing the collector voltage and controlling the gate signal actively. The new series connected IGBT gate driver is made and its validity is verified by the experimental results for series connected IGBT circuit.

• 전기의세계
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• v.13 no.3
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• pp.21-27
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• 1964

A method of triggering a series connected complementary transister flip-flop is described. Also measurements have been made for the operation region with respect to the input pulse variation. This circuit is compared with a Eccles-Jordan flip-flop when it used as a Nixie tube driver of a neon lamp driyer.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.4
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• pp.282-290
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• 2000

In this paper, the charge control with the input voltage feedback is proposed for the input series-output series-output parallel connected converter configuration for the high speed train power system application. This control scheme accomplishes the output current sharing for the output-parallel connected modules as well as the input voltage sharing for the input series connected modules for all operating conditions including the transients. It also offers the robustness for the input voltage sharing control according to the component value mismatches among the modules. And this configuration enables the usage of MOSFET for a high voltage system allowing a higher switching frequency for lighter system weight and smaller size. The performance of the proposed scheme is verified through the experimental results.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.195-197
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• 1998

The large scale industry needs high voltage converters. Therefore series connection of power semiconductor devices is necessary. It is important to prevent a device induced the overvoltage above ratings by proper voltage balancing in the field of IGBT series connection. In addition, the overvoltage induced by a stray inductance has to be limited in the high power circuit. This paper proposes a new gate control scheme which can balance the voltage properly and limit the overshoot by control the slope of collector voltage under series connected IGBT turn-off transient. The propose gate control scheme limits the overvoltage by sensing the collector voltage and controlling the gate signal actively. The new series connected IGBT gate driver is made and its validity is verified by the experimental results for series connected IGBT circuit.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.1
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• pp.99-104
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• 1999

The large scale industry needs high voltage converters. Therefore series connection of power semiconductor devices is necessary. It is important to prevent the overvoltage from being induced across a device above ratings by the proper voltage balancing in the field of IGBT series connection. In addition, the overvoltage induced by a stray inductance has to be limited in the high power circuit. This paper proposes a new gate control scheme which can balance the voltage properly and limit the overshoot by controlling the slope of collector voltage under the turn-off transient in the series connected IGBTs. The proposed gate control scheme which senses the collector voltage and controls the gate signal actively limits the overvoltage. The new series connected IGBT gate driver is made and its validity is verified by the experimental results in the series connected IGBT circuit.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.201-205
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• 1998

In this paper, the charge control with the input voltage feed forward is proposed for the input series-output parallel connected converter configuration for high voltage power conversion applications. This control scheme accomplishes the output current sharing for the output-parallel connected modules as well as the input voltage sharing for the input-series connected modules for all operating conditions including the transients. It also offers the robustness for the component value mismatches among the modules.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.455-459
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• 1998

In this paper input Series-Output Parallel connected converter configuration for high voltage power conversion applications is proposed and a control method to solve the problems of Input Series-Output Paralles connected converter configuration is introduced. In this configuration snubber circuit or voltage balancing controller that is necessary for the series connection of switching devices is not needed. The effectiveness of this proposed configuration is verified by simulation.

• Journal of Power Electronics
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• v.10 no.4
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• pp.388-395
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• 2010

An active boost converter for a single phase SRM using series-parallel connected capacitors is proposed in this paper. The proposed active boost converter has two diodes and one power switch with an anti-parallel diode and one additional boost capacitor. The additional boost capacitor could be series or parallel connected to the dc-link capacitor to produce proper excitation and demagnetization voltage. The proposed active boost converter can easily achieve a fast excitation and demagnetization from the capacitor connection. In this paper, series and parallel connected converters are reviewed, and the detailed operating modes as well as the voltage characteristics of the proposed converter are analyzed. The simulation and experimental results shows the effectiveness of the proposed active boost converter.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.6
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• pp.461-468
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• 2008

This paper presents a novel series connected DC/DC converter and a proper variable phase shift switching method in order to obtain high voltage ratio for fuel cell system. The proposed series connected DC/DC converter has same rectifier and LC filter for DC output voltage, so it can reduce the number of passive devices regardless of the converter number. In the conventional constant phase shift switching method, the proposed series connected DC converters have inverse bias output voltage. In order to overcome this problem, a simple but proper variable phase shift switching method is proposed in the a novel series connected DC/DC converter. In order to verify the proposed system, simulation and experiments are implemented.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.1
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• pp.88-93
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• 2016

LCL filters are widely used in high-order harmonics attenuation of output currents in grid-connected inverters. However, output currents of grid-connected inverters with LCL filters can become unstable because of the resonance of the filters. Given that the characteristics of output currents in inverters mostly depend on filter performance, the exact analysis of filters by considering parasitic components is necessary for both harmonics attenuation and current control. LCL filters have three or four parasitic components: the series and/or parallel resistance of the filter capacitor and the series resistance of the two filter inductors. Most studies on LCL filters have focused on the parasitic components of the filter capacitor. Although several studies have addressed the parasitic components of the filter inductor at the inverter side, no study has yet investigated the concurrent effects of series resistance in both filter inductors in detail. This paper analyzes LCL filters by considering series resistance in both filter inductors; it proposes an active damping method based on the virtual series resistance of LCL filters. The performance of the proposed active damping is then verified through both simulation and experiment using Hardware-in-the-Loop Simulator(HILS).