• 융합보안논문지
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• 제16권6_2호
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• pp.99-107
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• 2016

이 연구의 목적은 Bluetooth를 활용한 자동차의 내부망 통신네트워크를 해킹공격으로부터 예방하기 위한 대응방안을 제시하기 위함이다. 이를 위해 2장에서는 자동차 통신네트워크의 정의와 내부망 통신네트워크의 종류에 대해서 살펴보았다. 3장에서는 자동차 내부망 통신네트워크 해킹위험성을 분석하기 위해 Bluetooth에 의한 해킹범죄사례를 살펴보았다. 4장에서는 본 연구의 결과로서 첫째, "자동차안전기준에 관한 규칙" 개정이 이루어져야 한다. 동법에서는 전자제어시스템의 정의 및 기준사항과 안전운행을 위한 제작 및 정비를 규정해 놓았음에도 불구하고 전자제어시스템을 대상으로 한 해킹범죄 예방 및 방어와 관련된 보안프로그램 혹은 펌웨어 등의 제작과 관련된 규정이 없는 실정이다. 둘째, 자동차의 전자제어시스템 기술의 복잡성에 기인된 자동차 통신네트워크를 보호하고자 자동차 통신네트워크 보호 법률이 신설되어야 한다.

• 전력전자학회논문지
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• 제26권3호
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• pp.214-221
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• 2021

SiC MOSFETs require a faster and more reliable short-circuit protection circuit than conventional methods due to narrow short-circuit withstand times. Therefore, this research proposes a short-circuit protection circuit using a current-sensing circuit based on Rogowski coil. The method of designing the current-sensing circuit, which is a component of the proposed circuit, is presented first. The integrator and input/output filter that compose the current-sensing circuit are designed to have a wide bandwidth for accurately measuring short-circuit currents with high di/dt. The precision of the designed sensing circuit is verified on a double pulse test (DPT). In addition, the sensing accuracy according to the bandwidth of the filters and the number of turns of the Rogowski coil is analyzed. Next, the entire short-circuit protection circuit with the current-sensing circuit is designed in consideration of the fast short-circuit shutdown time. To verify the performance of this circuit, a short-circuit test is conducted for two cases of short-circuit conditions that can occur in the half-bridge structure. Finally, the short-circuit shutdown time is measured to confirm the suitability of the proposed protection circuit for the SiC MOSFET short-circuit protection.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
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• pp.59-62
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• 1993

The evaluation of the temperature of the motor in operation is necessary for smaller and lighter design of motors and for the determination of insulation class. And the evaluation of the temperature in thermal transient state is necessary for the determination of the intermittent rating and the protection from the thermal overload. The temperature can be calculated exactly by considering the loss distribution, the thermal resistances and the thermal capacities dependent on temperature. Using the detailed thermal equivalent circuit, the temperature of any local part of the motor can be evaluated. The comparison between the calculated results and the experiments is performed to verify the validity of the analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.232-234
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• 2002

Due to development of power electronics technology, power conversion system are tend to small size, easy to use and light weight. Especially motor control system have increased concerns and interests about IPM(Intelligent Power Module) inverter, which contains protection circuit, drive circuit and power devices. So, we manufactured 3-phase inverter using DIP-IPM(Dual in-line package IPM) PS21245- E(1.5 Kw) made by MITSUBISHI Electric. Some of these features include -HVIC to Provide level shifting and gate drive for high-side IGBTs. The interface circuit between pwm controller and DIP-IPM can made by direct connection. In order to validate dynamic performance of the proposed system, the actual experiment worked out at wide speed range. The developed system is shown as a good dynamic characteristics.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.28-30
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• 2002

In electrical machinery and apparatus, the most important problem is protect of machinery and apparatus in duo to transient phenomena and overload on operation. Particularly by advanced technology of late, there is demand for low cost of equipments and high percentage of use of equipments. Therefore, protection of machinery and apparatus in condition of overload is more valued considering that all efficiency increase is passed by operating all machinery and apparatus in condition of heavyload. In this paper, the suggested system is add overload protect system using CT in condition of overload.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.801-803
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• 2003

Faults in induction motors can be categorized into mechanical faults and electrical faults, and most mechanical faults result from inferiority or damage of the bearing, while most electrical faults derive from insulation faults of stator windings and rotor bar cracks. When a crack appears on the rotor bar, its efficiency decreases, which increases energy consumption and temperature, reducing the life span of the motor. This kind of fault can only be sensed by the protection relay after the condition has worsened to a certain degree, bringing massive economic loss. This paper will deal with the diagnosis method of rotor bar faults through the load current analysis method of the motor used during operation.

• 한국항해학회지
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• 제21권3호
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• pp.75-81
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• 1997

현재 자동차나 선박등에 사용하는 직류모터 속도 제어용 스위칭 소자는 스위칭 과전압으로 인하여 때때로 손상되거나 오작동을 일으키기쉽다. 본논문은 dc 모터 제어용 반도체 스위칭소자의 내성특성을 개선한 것이다. 이를 위하여, 먼저 저전압 보호소자인 비리스터나 제너 다이오드 등 가운데에서 스위칭 과전압에 대해 내성을 갖는 이상적인 소자를 선택하기 위해 과전압 보호자의 등가회로를 분석 하였다. 나아가서 국제규정에서 정의된 의사 과전압 파형의 적절한 선택, 스위칭 소자의 손상과정과 손상원인을 규명하고, 순시과전압 전류의 변화에 따른 각각의 임피던스 조건을 고려하여 직류모터 제어용 반도체 스위칭 소자의 내성특성 개선하였다.

• 한국자동차공학회논문집
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• 제24권1호
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• pp.16-23
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• 2016

The EWB(electronic wedge brake) is one in which the braking force is developed in a wedge and caliper system and applied to a disk and wedge mechanism. The advantage of the wedge structure is that it produces self-reinforcing effect and hence, utilizes minimal motor power, resulting in reduced gear and current. The extent of use of clamping force sensors and protection from failure of the EWB system directly depends on the level of vehicle mass production. This study investigated the mathematical equations, simulation modeling, and failsafe control algorithm for the clamping force sensor of the EWB and validated the simulations. As this EWB system modeling can be applied to motor inductance, resistance, screw inertia, stiffness, and wedge mass and angle, this study could improve the accuracy of simulation of the EWB. The simulation results demonstrated the braking force, motor speed, and current of the EWB system when the driver desired to the step and pulse the brake force inputs. Moreover, this paper demonstrated that the proposed failsafe control algorithm accurately detects faults in the clamping force sensor, if any.

• International Journal of Safety
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• 제10권1호
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• pp.36-40
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• 2011

Personnel maintaining or repairing the railway tracks or signaling facilities around tracks may experience the sensory disorder when doing maintenance works at the trackside of railway for long time. In this case personnel maintaining at the trackside may collide with the train since they cannot recognize the approach of motor-car although it approaches to the vicinity of maintenance workplace because of the sensory block phenomenon occurred due to their long hours of continued monotonous maintenance work. In order to prevent such motor-car accidents that may occur because railway track workers are unable to recognize the approaching train, the safety alarm equipment is developed to make the approaching motor-car send radio signals and bidirectional detection mechanism between approaching train and trackside personnel. It shows the possibility of utilization in various forms of safety equipment for workers only to the safety helmet to be worn by the maintenance workers while using the configuration of transmitting/receiving sides. In the paper it is represented new alarm equipment, which is the bone-anchored speaker-based safety helmet to be worn by the maintenance workers.

• 대한전기학회논문지:전력기술부문A
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• 제49권10호
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• pp.516-523
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• 2000

In this paper, intelligent methods using digital protective relay in power supervisory control system is developed in order to protect power systems by means of timely fault detection and diagnosis during operation for induction motor which has various load environments and capacities in power systems. The spectrum pattern of input currents was used to monitor to state of induction motors, and by clustering the spectrum pattern of input currents, the newly occurrence of spectrums pattern caused by faults were detected. For diagnosis of the fault detected, the fuzzy fault tree was derived, and the fuzzy relation equation representing the relation between an induction motor fault and each fault type, was solved. The solution of the fuzzy relation equation shows the possibility of each fault's occurring. The results obtained are summarized as follows: 1) The test result on the basis of KEMC1120 and IEC60255, show that the operation time error of the digital motor protective relay is improved within ${\pm}5%$. 2) Using clustering algorithm by unsupervisory learning, an on-line fault detection method, not affected by the characteristics of loads and rates, was implemented, and the degree of dependency by experts during fault detection was reduced. 3) With the fuzzy fault tree, fault diagnosis process became systematic and expandable to the whole system, and the diagnosis for sub-systems can be made as an object-oriented module.