• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.319-322
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• 1998

In this paper we further propose to add a very simple regenerative clamping circuit to SSIPP to reduce the voltage stress and to recycle the energy trapped in the leakage inductance of the isolation transformer, thus eliminating the need for a lossy snubber circuit. In addition, this proposed clamping circuit also provides a mechanism to reset the magnetizing current of the output transformer of SSIPP employing a Forward converter as the output stage. Simulations and experimental results are reported to verify the operation and performance of the SSIPP with regenerative clamping.

• Journal of Electrical Engineering and Technology
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• v.11 no.1
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• pp.257-264
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• 2016

In this paper, new electric railway feeding system which has active transformer is modeled for evaluating the steady state analysis using PSCAD/EMTDC. Equivalent models including power supply, feeder, train and transformers are proposed for simplifying the model of the feeding system in high speed electric railway. In case study, simulation results applied to proposed model are compared with the conventional and new systems through the catenary voltage, three-phase voltage of PCC (Point of Common Coupling) and the efficiency of regenerative braking energy.

• Journal of Power Electronics
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• v.9 no.5
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• pp.772-780
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• 2009

A novel soft-switching two-switch flyback converter is proposed in this paper. This converter is composed of two active power switches, a flyback transformer, a blocking diode, and two passive regenerative clamping circuits. The proposed converter has the advantages of a low cost circuit configuration, a simple control scheme, a high efficiency, and a wide operating range. The circuit topology, analysis, design considerations, and experimental results of the new flyback converter are presented.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2021-2023
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• 1998

In this paper we further propose to add a very simple regenerative clamping circuit to SSIPP to reduce the voltage stress and to recycle the energy trapped in the leakage inductance of the isolation transformer, thus eliminating the need for a lossy snubber circuit. In addition, this proposed clamping circuit also provides a mechanism to reset the magnetizing current of the output transformer of SSIPP employing a Forward converter as the output stage. Simulations and experimental results are reported to verify the operation and performance of the SSIPP with regenerative clamping.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.395-398
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• 2005

A novel full-bridge converter with a new energy-recovery driver implemented a regenerative transformer is proposed to improve the efficiency for wide input voltage range and load variation. The main switches achieve ZVS independent of the load current condition. During the free wheeling period, conduction loss is minimized by recovering the circulating energy to the source. The principle of operation, design consideration and experimental result, including efficiency, are presented in the case of large variation of the input voltage or load. A proposed 1kW converter prototype is compared with a PS-FB converter.

• Journal of the Korean Society for Railway
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• v.9 no.6 s.37
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• pp.652-656
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• 2006

Constant load model is widely used for an electric train to perform the static analysis of AT (Auto Transformer) feeding systems. In this model, the train will be considered as a constant load model when it drives or as a constant source model when it applies regenerative brake. However there must be some constraints imposed on the pantagraph voltage in actual operations. These constraints are established for the reason of protecting the feeding facilities from excessive rise of regenerative braking voltage or guaranteeing the minimum traction power of train. In normal operating situation, the pantagraph voltage of the train should be maintained within these limits. Keeping these facts in minds, we suggest new methods or analyzing AT feeding systems using the constant power models with the conditions of voltage constraints. The simulation results from a sample system using the proposed method illustrate both the states of system variables and the supply-demand relation of power among the trains and the systems very clearly, so it is believed that the proposed method yields more accurate results than conventional methods do. The proposed methods are believed to contribute to the assessment of TCR-TSC for compensating reactive powers too.

• Journal of Power Electronics
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• v.9 no.5
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• pp.809-821
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• 2009

This paper proposes a new phase-shift full-bridge DC-DC converter by applying energy recovery circuits to a conventional full-bridge DC-DC converter in plasma display panel applications. The converter can achieve soft-switching in main-switches by an extra auxiliary resonant network even with the wide operating condition of both output load and input voltage. The un-coupled design guidelines to the main bridge-leg component parameters for soft-switching operation contribute to conduction loss reduction in the transformer primary side leading to efficiency improvement. The auxiliary switches in the resonant network also operate in zero-current switching. This paper analyzes the operation modes of the proposed scheme and presents the key design guidelines through steady state analysis. Also, the paper verifies the validity of the circuits by hardware experiments with a 1kW DC/DC converter prototype.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.125-127
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• 2005

In this paper, the control algorithm of DC source device for inverter starting is proposed and the control method for compensating unbalance system source on operating time in the voltage type PWM converter with driving and regenerative faculty is suggested. The maintaining way of balancing condition for converter of AC source is used the compensating unbalanced status by current control loop. Because it is possible that the unbalanced System control is used to leakage transformer not equaled reactance by each phase in rectifier system, the proposed H/W and control algorithm of rectifier system is contributed to minimize of device and rising efficiency.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.75-76
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• 2014

This study deals with a isolation type MIC(Module Integrated Converter) for AC module with advantages such as DC Wireless, freely selectable installation capacity, minimized shadow effect etc. In this paper, MIC circuit with the function which can remove the ripple voltage of PV module and give the discharging path for charged energy in leakage inductance of isolation transformer. The validity of proposed circuir is verified by the simulation with PSIM.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.489-490
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• 2010

A novel soft-switching two-switch flyback converter is proposed in this paper. This converter is composed of two active power switches, a flyback transformer, and two passive regenerative clamping circuits.The proposed converter has the advantages of a low cost circuit configuration, a simple control scheme, a high efficiency, and a wide operating range. The circuit topology and experimental results of the new flyback converter are presented.