• Journal of the Korean Magnetics Society
• /
• v.26 no.4
• /
• pp.137-141
• /
• 2016

There is a growing demand for non-contact current measurements for efficient use of electrical power and energy saving. In this study, I propose a non-contact current sensor using LC resonance by a resonance circuit composed of a sensor coil and 2 coupling coils for enabling a wireless measurement. The inductance of the sensor coil, which could be changed by applied current, causes the change of resonance frequency of the resonance circuit. A pair of magnet was attached to the ferrite core to apply a bias magnetic field that enabled the determination of the current direction. We obtained an output voltage change of 18 V with the current of -3~3 A. But, the output was nonlinear. In order to realize the non-contact current measuring method proposed in the present study, there is a need for a strict investigation of linearity and resolution for the future study.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.1754-1755
• /
• 2007

영구자석을 사용한 마커가 설치된 자기장 이동 경로에서 이동 로봇의 경로 인식을 위한 위치인식 시스템이다. 저가의 홀센서를 일정 간격의 열로 배치한 센서를 설계 제작하고, 그 센서를 이용하여 측정된 마커의 자계 값을 이용하여 경로상의 위치를 인식할 수 있도록 하였다. 마커의 극성을 인식하는 새로운 방법을 제시하고, 인식된 극성을 코드화하여 경로상의 특이점들에 배치함으로써 경로 이동 중에 그 점들의 위치를 인식하도록 하였으며, 로봇은 그 위치에서 미리 정해진 행동을 하도록 프로그램 하였다. 센서들 간의 통신 방법을 논하였고, 각 센서들에서 얻어진 정보로부터 이동 로봇의 경로상의 위치인 측방향 변위 오차와 방향각 오차를 기하학적으로 산출한다.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.6 no.4
• /
• pp.22-28
• /
• 2003

In the conventional weapon system, such as gun and small arms, it Is a general trend that for maximization of its performance and enhancement of its effectiveness, the firing control system(FCS) is developed and applied with the guns and small arms in the world. The FCS of the small arms for infantry man is composed of a few of sensors for acquisition of input data of FCS, such as range measurement, position sensing of weapon, temperature, etc., computer, displayer and power pack, and also the air burst munition is developed in parallel for the maximization of FCS's effectiveness. Since the flight time setting fuze for the air burst munition is adapted for next me, the measuring device of the muzzle velocity is needed to overcome the variation of muzzle velocity due to producing procedures and the differences of the using temperatures and so maintain the burst position accuracy This paper contained the technical information on the development of the measuring device of muzzle velocity, which designed in compact & light weight configuration with reliability and accuracy.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.43 no.6
• /
• pp.1001-1009
• /
• 1994

The present paper deals with a new developed sensor for measuring the time-varying magnetic fields and describes the experimental results of trasient magnetic field that takes place during the operations of electric appliance. The operation principle of the self-integrating magnetic field sensor by using coaxial cable is analyzed and a calibration investigation is carried out. The frequency bandwidth of the magnetic field measurement system is from 40 Hz to about 300 kHz. The magnetic field induced by the starting and/or operation of electric appliance mainly includes the odd harmonics such as the third, the fifth and the seventh harmonics. The magnetic field intensity caused during the operation of ultrasonic washer is inversely proportional to distance, this correspodns to induction component. As a result, it was known that the odd harmonics of magnetic field in the desing of electromagnetic shield employed for protecting electronic circuit and control devices have to be considered.

• Proceedings of the KIEE Conference
• /
• 1999.07b
• /
• pp.576-578
• /
• 1999

본 연구의 목적은 자계방향 기준 벡터제어 이론에 기초하여 속도 센스리스 벡터제어를 구현하는 것이다. 속도센스리스 벡터제어에서 속도추정 방법은 관측기에서 얻은 상태량을 취하는 MRAS 방법이 제안되고 있지만 이득정수의 조정을 행하여야 하는 결점을 가지고 있다. 본 논문에서는 속도추정은 관측기 이론에 기초하여 2차자속 관측기와 전류센스에서 검출한 전류 값으로 행하는 새로운 속도 추정법을 이용한 제어 알고리즘을 제안한다. 그리고 제안한 방법이 본 연구에 있어서 사용한 자계방향 벡터제어시스템의 실현에 가능성이 있음을 시뮬레이션으로 검토하고 실제로 시스템을 구현하여 센스리스 속도제어를 달성하였다.

• Proceedings of the KIEE Conference
• /
• 1994.07a
• /
• pp.91-93
• /
• 1994

Recently, for improving the power supply reliability and for rationslizing maintenance, new maintenance and monitoring systems are stornagly desired for use in the field of electric power transmission. In this paper, we describes the optical fault detecting method of underground power transmission lines using bareearth doped YIG Faraday sensors which are very light, small size and fast response. As regarding, we use the zero phase current detecting algorithm at insulated joints.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.10a
• /
• pp.938-941
• /
• 2007

The most of humonoid robot which is utility for the existing industry use a magnetic sensor and infrared sensor and route in their courses consist of guidance or the optical tape. It is impossible to establish courses in the room that is the working environment of the humonoid robot. So It has need of the development of the flexible humonoid robot. In this paper, we describe the map building method combined with ultrasonic sensors and infrared sensor additionally.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1999.07a
• /
• pp.94-94
• /
• 1999

반도체 Hall 효과를 이용하여 자계를 검출하여 이를 전압신호로 출력하는 자기센서로는 주로 GaAs, InSb, InAs 등의 박막이 사용되고 있다. 자기센서의 응용분야가 최근에는 직류전류의 무접촉 검출, 자동차의 무접촉 회전 검출, 산업용 기계의 제어용 무접촉 위치검출 분야로 확대되고 있어 그 수요가 급증하고 있다. 이중 Hall 소자의 응용분야중 많은 활용이 기대되고 있는 자동차용 무접촉 센서는 -4$0^{\circ}C$~15$0^{\circ}C$의 온도범위에서 안정하게 작동하여야 하므로 온도 안정성이 매우 중요하다. 그러나 Hall 소자 시장의 80%를 점유하고 있는 InSb Hall 소자는 온도가 올라감에 따라 저항이 급격히 낮아지는 성질을 가지고 있으므로 10$0^{\circ}C$ 이상의 온도에서 사용하는 것이 불가능하다. 한편 InAs(에너지갭~0.18eV)는 InSb보다 에너지 갭이 크므로 고온에서도 작동이 가능하고 자계변화에 따른 출력의 직진성이 매우 좋다는 장점을 가지고 있다. 이러한 InAs Hall 소자를 실현하기 위해서 가장 중요한 것이 고품위의 InAs의 박막 성장기술이다. InAs 박막을 성장하기 위해서 사용되고 있는 기판은 GaAs이다. 그러나 GaAs 기판과 InAs 박막 사이에는 약 7% 정도의 격자부정합이 존재하기 때문에 높은 이동도를 가지는 고품위 박막을 성장시키기가 매우 어렵다. 이에 본 연구에서는 분자선에피택시 방법을 이용하여 GaAs 기판위에 고품위의 InAs 박막을 성장하는 기술을 연구하였으며, 성장된 InAs 박막의 특성을 DCX 및 Hall effect 등으로 조사하였다. InAs 박막 성장시 기판은 <0-1-1> 방향으로 2$^{\circ}$ off 된 GaAs(100)를 사용하였다. InAs 박막성장시 기판온도는 48$0^{\circ}C$로 하고 GaAs buffer 두께는 2000$\AA$로 하여 As flux 및 Si doping 농도등을 변화시켰다. 그 결과 Si doping 농도 2.21$\times$1017/am에서 10,952cm2/V.s의 이동도를 얻었다.

• Journal of Sensor Science and Technology
• /
• v.10 no.2
• /
• pp.134-141
• /
• 2001

This paper describes a method to steer an autonomous electric vehicle using magnetic fields. Magnets are embeded along the center of the road and a magneto-resistive sensor is mounted beneath the front bumper of the vehicle. As the vehicle moves along the road neural network controller controls the vehicle using measured magnetic field variation. Based on a single magnets modeling equation, we analyzed three dimensional magnetic field distributions of embeded magnets in series on the center of the road and performed a computer simulation using this results. In simulation study, straight and curved road was configured. The steering controller for the vehicle was designed using neural network and experiment was performed on the real embeded magnets using real autonomous electric vehicle. At the experiment we compensated the earth's magnetic fields and showed a good result driving an autonomous vehicle using proposed method.

• Journal of Convergence for Information Technology
• /
• v.12 no.5
• /
• pp.133-138
• /
• 2022

In previous studies to obtain the residual magnetic flux of the transformer using the leakage magnetic flux, a transfer function was used. The transfer function was consisted with the leakage magnetic flux measured outside the transformer and the residual magnetic flux measured at the moment passing through the two ± residual points. In this study, a method of calculating the ratio of the maximum operating leakage flux to the residual leakage flux was proposed The advantage of this method is to avoid the uncertainty of the transfer function due to current noise. Then, the noise of the sensor was measured to investigate the effect of the drift of the noise on the measurement results. Comparing the residual leakage magnetic flux density with 80nT of the drift noise, 66 times or more at a distance of 10 mm and 5 times or more at a distance of 100 mm were obtained. 100mm was the maximum measurement distance to obtain the residual magnetic flux.