• Proceedings of the KIEE Conference
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.855-857
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• 2000

Brake system using eddy current is adequate to obtain safe braking force in high speed transportation system and electric vehicle etc. In this paper, we propose the new type eddy current braker using Halbach array. which compared with the conventional permanent magnet array. The airgap flux density of Halbach array is higher 25% then conventional array, therefor we can predict that braking force is much large 1.56 times then conventional array.

• Journal of Magnetics
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• 제17권1호
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• pp.33-35
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• 2012

A magnetic brake system was fabricated for use with small wind turbines. The torque of the pivot did not change as the speed of revolution increased when the magnetic array disc was far from the salient of the aluminum housing, the torque abruptly increased as the magnetic array approached the salient of the aluminum housing. The torque increased as a quadratic function of the speed of revolution when the distance between the magnetic array and the datum point was 60 mm.

• Proceedings of the KIEE Conference
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1226-1228
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• 2002

Permanent magnet is applied to the mover of eddy current braking system for high speed. On the analytical 2D field solutions considering end effect, this paper deals with the magnetic field, and forces according to the secondary magnet array. Comparisons between analytical results and experimental results are also presented.

• Progress in Superconductivity and Cryogenics
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• 제2권2호
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• pp.44-48
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• 2000

The high temperature superconducting bulk can be used as the rotor of an ac motor. This paper presents the fabrication and test results of a ac motor with HTS bulk rotor. The rotor of a conventional squirrel cage induction motor was replaced with cylinder type YBCO bulk. Height and outer diameter of the HTS bulk was 15mm and 46mm, respectively. Eddy current brake using aluminium disk was used to measure the torque of the HTS motor. No load test, locked rotor test and load test were performed to examine the characteristics of the HTS motor. Test results show the motor can rotate at synchronous speed without any special starting circuit. Maximum output power of the constructed HTS motor was 408W.

• The Transactions of the Korean Institute of Power Electronics
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• 제21권5호
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• pp.396-403
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• 2016

Usually, large-sized buses and trucks have a very high load. In addition, frequent braking during downhill or long-distance driving, causes the conventional method using the brake friction to have a problem in safety because of brake fade and brake burst phenomenon. Auxiliary brakes dividing the braking load is essential. Hence, environment-friendly auxiliary brakes, such as contactless brake rather than the engine auxiliary brake system are needed. A study aimed at improving the energy efficiency by recharging electric energy with changing mechanical to electrical energy that occurs when braking is actively in progress. In this paper, the voltage control method is utilized to recover the electric energy generated in the electromagnetic retarder instead of the eddy current. To regenerate the braking energy into the electrical energy, the resonant L-C circuit is configured in the retarder. The voltage generated in the retarder is simply modeled as a transformer. However, retarder voltage control in this paper is simulated by modeling the induction generator because this induction generator modeling is more practical than transformer modeling. The changes in the voltage of the resonance circuit, which depends on the switch pulse duration of the control device, were analyzed. A PI controller algorithm to control this voltage is proposed. The feasibility of modeling retarder and voltage controller are shown by using MATLAB Simulink in this paper.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제48권5호
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• pp.355-361
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• 2020

Among these satellites, low - orbit small satellites with military characteristics require multi - target observation, and demand for high-resolution photographs and images is increasing. Fast maneuverability is the most important factor for high-resolution images and multi - target observations. However, in the case of a small satellites, it is possible to perform the attitude maneuver if it has high speed, but the residual vibration occurs when the attitude maneuver is completed and the next attitude maneuver is completed. In this study, to verify the vibration characteristics of the plate generated after attitude maneuver, an experimental fixture for simulating the attitude maneuver was fabricated and tested. In addition, Eddy Current Damper (ECD) using Eddy Current Brake system (ECB) is proposed as a passive damping method using permanent magnet to reduce vibration. A mathematical model was established to apply ECD and it was experimentally implemented according to the magnetic flux density and the air gap of the permanent magnet. One plate of four solar panels (plate) was specified, the residual vibration reduction performance after the test was verified experimentally.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제66권8호
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• pp.1207-1214
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• 2017

In the case of frequent braking, when driving downhill or long distance, conventional brakes using friction are problematic in braking safety due to brake rupture and fading phenomenon. Therefore auxiliary brakes is essential for heavy vehicles. And several research has been actively conducted to improve energy efficiency by regenerating mechanical energy into electric energy when the vehicles brake. In this paper, a voltage control method is utilized to recover the electric energy generated in the electromagnetic retarder instead of the eddy current. To regenerate the braking energy into the electrical energy, a resonant L-C circuit is configured in the retarder. The retarder can be modeled as self-excited induction generator due to its operating principle. The driving conditions according to the retarder's parameters are made into 3-D maps. Also, the voltage of the resonant circuit changing depending on the driving pulse applied to the FET was analyzed. For the control of this voltage, we proposed an algorithm using the PI controller. The controlled voltage is converted by a 3-phase AC/DC converter and then charged to a battery inside the heavy vehicles through a DC/DC converter. Electromagnetic retarder and its controller are validated using Matlab Simulink. We also demonstrate the voltage controller through the actual M-G set experiment.

• Proceedings of the KIEE Conference
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1238-1240
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• 2002

고속전철의 새로운 제동개념인 와전류제어 제동방식에서는 출력 자화력의 제어를 위해서 전류제어 시스템이 필요하다. 본 논문에서는 신개념의 전력제어 소자인 IGCT(Insulated Gate Commutated Thyristor)를 초퍼회로에 적용한 스너버회로가 없는 형태의 고속전철용 와전류 제어장치의 개발에 대하여 설명하였다. 회로의 성능을 파악하기 위하여 주회로 시뮬레이션을 실시하였으며 대상체인 부하 마그네트를 연결한 고전압 출력 시험을 통해 장치의 성능을 조사하였다.