• Journal of Power Electronics
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• v.10 no.1
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• pp.27-33
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• 2010

This paper presents a bidirectional DC-DC converter suitable for low-voltage super capacitor-based electric energy storage systems. The DC-DC converter presented here consists of a full-bridge circuit and a current-fed push-pull circuit with a high frequency (HF) transformer-link. In order to reduce the device-conduction losses due to the large current of the super capacitor as well as unnecessary ringing, synchronous rectification is employed in the super capacitor-charging mode. A wide range of voltage regulation between the battery and the super capacitor can be realized by employing a Phase-Shifting (PS) Pulse Width Modulation (PWM) scheme in the full-bridge circuit for the super capacitor charging mode as well as the overlapping PWM scheme of the gate signals to the active power devices in the push-pull circuit for the super capacitor discharging mode. Essential performance of the bidirectional DC-DC converter is demonstrated with simulation and experiment results, and the practical effectiveness of the DC-DC converter is discussed.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.6
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• pp.173-179
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• 2009

Recently, the super capacitor(EDLC) which has drawn attention as a new energy storage element has a lot of advantage such as no maintenance, long lifetime and quick charge/discharge characteristics with large current. The objective of this paper is propose a parameter measurement method to detect the changes in equivalent series resistor (ESR) and the capacitance value of a super capacitor in order to analysis the internal characteristic and worn-out state of a super capacitor. For proposed method, only the capacitor voltage measurement using simple analog switch is required. In addition, experimental results of voltage sag compensation system in order to compensate the input voltage drop during short-term power interruption adopted super capacitor are presented.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.212-214
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• 2007

Regenerative energy which is generated during brake periods of DC traction might cause malfunction or destruction of rectifier or any other power conversion devices caused the increment of DC line voltage. Regenerative energy storage system using super-capacitor is one of the method to control the DC line voltage safely. And super-capacitor is very important device as energy storage device. Therefore, In this paper, we designed the regenerative energy storage system using super-capacitor and propose the method about predicting the lifetime of super-capacitor established in storage system. According to the this research, we can estimate the proper replacement moment for the existed super-capacitor due to the safety of the system. And improve the reliability of regenerative energy storage system using super-capacitor.

• Proceedings of the Safety Management and Science Conference
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• 1999.11a
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• pp.345-354
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• 1999

A new type of capacitor named "Super Capacitor" has been developed, in which the properties of electric double layer formed at the interface of activated carbon electrode- liquid organic electrolyte is applied. This capacitor is small In size, light in weight, wide In temperature range(-25~$70^{\circ}C$), large in charge-discharge capability and good in voltage preservation. And this super capacitor is applied as a power back-up for electricity failure in volatile memory devices etc., a power source for a short time and a power source for operating actuators. At present the development of high power back-up types of the capacitor system and improvement of their characteristics are being actively conducted in order to find wider applications.lications.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.4
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• pp.247-256
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• 2008

Regenerative energy generated by regenerative braking of DC traction can cause the system malfunction or damage to the rectifier, or malfunction of the power conversion device in power supply system by DC Line voltage rise in feeder line. Regenerative energy storage system using super capacitor is one of the ways to stabilize DC line voltage. In this paper, energy storage system of DC traction system using super-capacitor bank is implemented and using the field measurement data of the station N and the station S on the Line 2, the operation characteristics of line voltage caused by regenerative energy of electric trains are verified. Also, charge/discharge characteristics of super capacitor are verified as well. Thus, we can verify the operation characteristics of super-capacitor bank for regenerative energy storage system installed in DC Traction. And if we can use field measurement data of DC line voltage, we have obtained cost reduction. The stabilization of the system will be improved by measuring the operation characteristics of regenerative energy storage system in certain section operated by DC traction and predicting the capacity and lifetime of super-capacitor.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.5
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• pp.410-414
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• 2007

To prevent degradation of battery efficiency generated by serious current variation in rechargeable batteries, we researched a hybrid battery combining a super capacitor and a rechargeable battery. The hybrid battery shows high efficiency in a lifetime and a voltage drop. The hybrid battery was composed of a rechargeable battery, a current regulator and a super capacitor that can be used with supporting power. Before the experiment, the hybrid battery was simulated for current regulation and an electric current in a super capacitor by using the Pspice program. After that, we compared the efficiency of the hybrid battery with the efficiency of the normal battery. In this result, we demonstrated that the hybrid battery has a higher efficiency and a longer lifespan than the normal battery.

• Proceedings of the KIEE Conference
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• 2008.11b
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• pp.74-76
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• 2008

본 논문에서는 Super-Capacitor라 불리우는 EDLC(전기이중층콘덴서)의 고장진단을 위한 파라미터의 특성 해석에 관한 연구를 수행하였다. 에너지의 저장 및 전압연계를 위한 전력변환장치에는 납측전지 또는 전해커패시터를 사용하여 왔으나 환경문제 및 에너지밀도의 측면에서 불리하여 최근에는 Super-Capacitor의 사용이 주목을 받고 있다. 본 논문에서는 이러한 EDLC의 내부 특성을 해석하기 위하여 EDLC의 등가직렬저항 및 정전용량을 측정하여 진단데이터에 활용이 가능토록 하였으며, 또한 EDLC를 적용한 순간전압 보상장치의 응용 실험을 수행하여 그 결과를 제시하였다.

• Journal of Biosystems Engineering
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• v.43 no.2
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• pp.94-102
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• 2018

Purpose: In this study, a maintenance free super-capacitor battery charging system based on the photovoltaic module, to be used in agricultural electric carriers, was developed and its charging characteristics were studied in detail. Methods: At first, the electric carrier system configuration is introduced and the electric control components are presented. The super-capacitor batteries and photovoltaic module used in the experiment are specified. Next, the developed charging system consisting of a constant current / constant voltage Buck converter as the charging device and a super-capacitor cell as a balancing device are initiated. The proposed circuit design, a developed PCB layout of each device and a proportional control to check the current and voltage during the charging process are outlined. An experiment was carried out using a developed prototype to clarify the effectiveness of the proposed system. A power analyzer was used to measure the current and voltage during charging to evaluate the efficiency of the energy storage device. Finally, the conclusions of this research are presented. Results: The experimental results show that the proposed system successfully controls the charging current and balances the battery voltage. The maximum voltage of the super-capacitor battery obtained by using the proposed battery charger is 16.2 V, and the maximum charging current is 20 A. It was found that the charging time was less than an hour through the duty ratio of 95% or more. Conclusions: The developed battery charging system was successfully implemented on the agricultural electric carriers.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.11
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• pp.843-847
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• 2010

This paper in concerned with the electrochemical properties for supercapacitor of composition with variation of super P/MWCNTs(multi-walled carbon nanotubes) contents. Electrochemical properties of the super P/MWCNTs were measured by cyclic voltammetry at the scan rates of 0.5 mV/s is $TEABF_4$(tetra-ethyl-ammonium-tetra-fluoro-borate) as electrolytes. As a result, the composition for 6 wt% content of MWCNTs led to an increase of capacitance, but DC resistance were decreased. It was found that the content and dispersion appearance of MWCNTs was attributed to the increase in capacitance and lower DC resistance.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.6
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• pp.24-33
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• 2006

This experiment explains about electrical braking equipment which will be used for 1.2kW PEMFC HEV. The equipment is made of BLDC motor and super capacitor(EDLC). The circuit is designed for regeneration braking that can save the energy from low voltage of generation with BLDC motor. Increasing a regeneration energy from braking system is effected with regeneration current and SoC of super capacitor(EDLC). Electrical braking in electrical vehicle is suitable for regeneration braking with dynamic braking together.