• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.3
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• pp.544-551
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• 2011

This paper presents the circuit arrangement and effective control method of regenerative energy storage system for an electric vehicle using super-capacitors as the braking energy storage element. A bi-directional controlled current flow of the DC-DC converters with the capacitor bank is connected in parallel with battery, and is controlled so that the whole of the braking energy is effectively absorbed into the capacitors and released back to the electric motor upon acceleration. The converter needs the series-parallel switching circuit for making the best use of the series capacitors and for limiting the step-up ratio of the boost converter. The proposed methods are verified by computer simulation and experimental set-up. They are usefully applied to the electric vehicles such as green cars, electric motorcycles, bike, etc which are power- supplied by the electric batteries.

• International Journal of Automotive Technology
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• v.5 no.4
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• pp.287-295
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• 2004

A performance simulator for the fuel cell hybrid electric vehicle (FCHEV) is developed to evaluate the potentials of hybridization for fuel cell electric vehicle. Dynamic models of FCHEV's electric powertrain components such as fuel cell stack, battery, traction motor, DC/DC converter, etc. are obtained by modular approach using MATLAB SIMULINK. In addition, a thermodynamic model of the fuel cell is introduced using bondgraph to investigate the temperature effect on the vehicle performance. It is found from the simulation results that the hybridization of fuel cell electric vehicle (FCEV) provides better hydrogen fuel economy especially in the city driving owing to the braking energy recuperation and relatively high efficiency operation of the fuel cell. It is also found from the thermodynamic simulation of the FCEV that the fuel economy and acceleration performance are affected by the temperature due to the relatively low efficiency and reduced output power of the fuel cell stack at low temperature.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.12
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• pp.868-873
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• 1987

In this pater, we have proposed a synthetic main chopper circuit for the chopper controlled electric automobile. The proposed chopper circuit operates as a step-down chopper in powering mode and as a polarity reversion type chopper in regenerative braking mode. In this study, it was found that powering and regenerative braking operations using the separately excited D.C motor can be controlled continuously only by gate signals of the chopper without changing the connection of the circuit.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.9
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• pp.1492-1498
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• 2003

This study proposes a new conceptual Hybrid Electric Brake System (HEBS) which overcomes problems of a conventional hydraulic brake system. HEBS adopt a contactless type bake system when a vehicle speed is high, to obtain superior braking performances by eddy current. On the contrary, when a vehicle speed is low, HEBS employs a contact type brake system such as conventional hydraulic brake system to generate higher brake force. Therefore, HEBS transfers faster the braking intention of drivers and guarantees the safety of drivers. Braking torque analysis is performed by using a mathematical model which is proposed to investigate the characteristic of a vehicle dynamics when the brake torque is applied. Optimal torque control is achieved by maintaining a desired slip corresponding to the road condition. The results show that HEBS reduces the stopping distance, saves the electric energy, and increases the stability.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.8
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• pp.485-494
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• 2016

In this work, we conducted a study of fuel consumption characteristics and regenerative braking recovery rate by conducting an experiment using a TMED type parallel hybrid electric vehicle. As regenerative braking technology is considered essential to improve the energy efficiency of the hybrid vehicle, it is necessary to conduct research on the regenerative braking system. Therefore, the electrical characteristics, current balance, and fuel consumption were investigated using an EC type chassis dynamometer with experimental conditions as per IM240 mode. From the results, it was observed that when the initial SOC condition was lower, the engine operating time of the hybrid vehicle increased, and the energy efficiency decreased. While operating in the driving mode characteristics condition and the driving characteristics condition, the difference in the average fuel consumption was not significant. However, after completion of the experiment, there was a difference in the engine operation.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.2
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• pp.77-83
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• 2000

This paper deals with the design of a touch free eddy-current brake for high speed transportation systems by using 2-dimensional Finite Element Method (2-D FEM). The eddy current brake systems have to equipped with maximum braking force and deceleration at the given volume or mass, high braking force at small rate, attraction forces as small as possible and stable construction. The parameters, such as the number of pole, electric ampere-turns and slot width have influence on these braking characteristics. For the magnet to satisfy above-mentioned performance in high speed, the braking performance according to variation of the parameters are analyzed by the 2-D FEM. In addition, the magnet stack width is determined from equivalent stack width that is calculated by solution of the Field with scalar potential. From these results, the magnet of optimized configuration with maximum braking force and minimum attraction force is designed by the process of detail design.

• Journal of Energy Engineering
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• v.20 no.4
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• pp.286-291
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• 2011

The hybrid vehicle has a good fuel economy with a electric type braking energy regeneration system. This paper introduced a novel pneumatic type braking energy regeneration system. The novel system use a scroll mechanism which have both compression function and expansion function. While vehicle is decelerating, the scroll machinery, being operated as a scroll compressor, compress a atmospheric air to save the vehicle's kinetic energy and reuse a compressed air which is reserved in a air tank while vehicle is accelerating. In order to analyze fuel improvements by applying braking energy regeneration system to a vehicle, we simulated the rate of braking energy regeneration through CVS-75 mode driving patterns.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1461-1467
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• 2009

The electric railway is a clean and energy saving system, because it requires relatively less energy than automobiles by transporting the same passengers or goods. Six thousands of vehicles are operated on Korean urban transit system. This system is 95% of regeneration system. Especially, the VVVF-Inverter vehicle has a merit of the highest regeneration rate. Energy consumption is 90% for traction and 10% for auxiliary supply. Braking energy is about 40% of energy consumption. Up to 40% of the tractive power of vehicles capable of returning energy to the power supply can be regenerated during braking and that this energy can be used to feed vehicles which are accelerating at the same time. The energy generated by braking vehicle would simply be converted into waste heat by its braking resistors if no other vehicle is accelerating at exactly the same time. Such synchronized braking and accelerating can not be coordinated, the ESS(energy storage system) stores the energy generated during braking and discharges it again when a vehicle accelerates. This paper presents field tests about the energy saving rate of the developed ESS. when the ESS is on/off, energy saving rate of the ESS is tested. The verification test in the field focused on energy saving.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.115.1-115
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• 2002

This study proposes a new conceptual Hybrid Electric Brake System (HEBS) which overcomes the problems of the conventional hydraulic brake system. The HEBS uses the contactless brake system when vehicle speed is high to obtain superior braking force by eddy current, which is induced in pole area by magnetic flux through a rotating conductive disk. On the contrary, when a vehicle speed is low, contact type brake system such as conventional hydraulic brake system makes higher braking force. HEBS transfers faster a braking intention of drivers and guarantees a safety of drivers because of vehicle dynamic superior controllability. Braking torque analysis is peformed based upon Lee. Barn\ulcornermath...

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.240-244
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• 1989

This paper describes an electric vehicle DC-DC drive system capable of delivering motoring current and of generating braking current. The power transistor chopper Is adopted to operate a DC series motor. The transistor chopper adopted, a high chopping frequency and avoids additional inductance In series with the armature winding. The four-quadrant drive is applied to save the energy. The energy saving is critical in operating the Independent power source electric vehicle. Using software simulation, regeneration and braking characteristics are investigated. The microprocessor-based controller is used to operate the whole system.