• 센서학회지
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• 제30권5호
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• pp.342-348
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• 2021

For the characterization or failure analysis of electronic devices such as PCB (printed circuit boards), the most common method is the measurement of voltage waveforms with an oscilloscope. However, because there are many types of problems that cannot be detected by voltage waveform analysis, several other methods such as X-ray transmission, infrared imaging, or eddy current measurement have been applied for these analyses. However, these methods have also been limited to general analyses because they are partially useful in detecting physical defects, such as disconnections or short circuits. Fundamentally current waveform measurements during the operation of electronic devices need to be performed, however, commercially available current sensors have not yet been developed, particularly for applications in highly integrated PCB products with sub-millimeter fine pitch. In this study, we developed a highly sensitive PHR (planar hall resistance) magnetic sensor for application in highly integrated PCBs. The developed magnetic sensor exhibited sufficient features of an ultra-small size of less than 340 ㎛, magnetic field resolution of 10 nT, and current resolution of 1 mA, which can be applicable for PCB analyses. In this work, we introduce the development process of the magnetic sensing probe and its characteristic results in detail, and aim to extend this pin-type current probe to applications such as current distribution imaging of PCBs.

• 조명전기설비학회논문지
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• 제21권10호
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• pp.59-65
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• 2007

최근 유비쿼터스 센서네트워크 기술이 전력설비관리에 적용되어 오고 있다. 본 연구에서는 가공배전선로에서 전력용변압기와 피뢰기를 관리할 수 있는 유비쿼터스 센서의 설계 및 제작에 대해 기술하였다. 이 센서들은 8-[bit] 마이크로프로세서, IEEE 802.15.4기반 무선통신모듈과 주변 전자회로로 구성되어 있다. 변압기의 부하 및 서지전류 측정에는 1000[A]까지 포화되지 않고 선형성을 유지할 수 있도록 공심형 로고우스키 코일을 제작하여 적용하였다. 피뢰기를 흐르는 $50[{\mu}A]{\sim}1[mA]$의 미소누설전류를 측정하기 위하여 180[Hz]에서 $10^5$의 고투자율을 갖는 영상변류기를 사용하였으며, 피뢰기 감시모듈의 -3[dB] 주파수 대역은 12[Hz]에서 1.24[kHz]이다.

• 전자공학회논문지
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• 제52권10호
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• pp.161-167
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• 2015

본 논문에서는 첨단 주택에서 가전기기 에너지 절약을 위한 재실 기반 에너지 절약 시스템을 제안하였다. 제안된 시스템은 센싱 시스템과 홈 게이트웨이 시스템으로 구성된다. 센싱 시스템은 사람의 움직임을 감지하는 PIR 센서를 장착한 무선 센싱 노드와 CT센서를 이용하여 전류 사용량을 측정하고 무선으로 전달하는 스마트 플러그로 구성된다. 스마트 플러그를 이용하여 가전기기의 전류 소모량을 측정하고, 방과 문에 설치한 재실 감지 센서를 이용하여 거주자의 재실 유무를 확인하였다. 제안한 시스템은 부재 공간의 불필요한 전기 에너지 사용량을 스위치를 끔으로서 절약한다. 실험 결과 재실 기반으로 전기 에너지를 절약한다면 약 34%를 절약할 수 있음을 확인하였다.

• 조명전기설비학회논문지
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• 제21권4호
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• pp.80-87
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• 2007

This paper will suggest that the 1 cross orthogonal loop type sensor improves on the orthogonal loop form sensor-head, which is available a calibration of the linear birefringence, when a fiber optic current sensor was composed. An output characteristics of the 1 cross orthogonal loop form, a general closed loop form, the orthogonal loop form are compared by the IEC(International Electrotechnical Commission) 60044-8 standard, and the state of polarization is compared with three forms. As a result, when the closed loop form was changed to the orthogonal loop form, retardation decreased 15.3[%]. When the closed loop form was changed to the 1 cross orthogonal loop type, the retardation decreased 33.8[%]. As a result of the Faraday Effect measurement, the 1 cross orthogonal loop form has the highest output characteristic and the lowest error ratio. It met the 0.5 class of the IEC 60044-8 standard. Thus, in application of the 1cross orthogonal loop form, the possibility to develop high reliability fiber optic current sensors that have a high output and stable error ratio rises is increased.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제9권2호
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• pp.99-104
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• 2009

The turn-to-turn short is one major fault of the motor faults of BLDC motors and can appear frequently. When the fault happens, the motor can be operated without breakdown, but it is necessary to maintain the motor for continuous working. In past research, several methods have been applied to detect winding faults. The representative approaches have been focusing on current signals, which can give important information to extract features and to detect faults. In this study, current sensors were installed to measure signals for fault detection of BLDC motors. In this study, the Park's vector method was used to extract the features and to isolate the faults from the current measured by sensors. Because this method can consider the three-phase current values, it is useful to detect features from one-phase and three-phase faults. After extracting two-dimensional features, the final feature was generated by using the two-dimensional values using the distance equation. The values were used in fuzzy similarity to isolate the faults. Fuzzy similarity is an available tool to diagnose the fault without model generation and the fault was converted to the percentage value that can be considered as possibility of the fault.

• Journal of Magnetics
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• 제15권4호
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• pp.204-208
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• 2010

Local wall thinning in pipelines affects the structural integrity of industries like nuclear power plants (NPPs). In the present study, a pulsed eddy current (PEC) differential probe with two excitation coils and two Hall-sensors was fabricated to measure the wall thinning in insulated pipelines. A stainless steel test sample was prepared with a thickness that varied from 1 mm to 5 mm and was laminated by plastic insulation to simulate the pipelines in NPPs. The excitation coils in the probe were driven by a rectangular current pulse, the difference of signals from two Hall-sensors was measured as the resultant PEC signal. The peak value of the detected signal is used to describe the wall thinning. The peak value increased as the thickness of the test sample increased. The results were measured at different insulation thicknesses on the sample. Results show that the differential PEC probe has the potential to detect wall thinning in an insulated NPP pipelines.

• International Journal of Korean Welding Society
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• 제2권2호
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• pp.51-56
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• 2002

The weld seam tracking system for arc welding process uses various kinds of sensors such as arc sensor, vision sensor, laser displacement sensor and so on. Among the variety of sensors available, electro-magnetic sensor is one of the most useful methods especially in sheet metal butt-joint arc welding, primarily because it is hardly affected by the intense arc light and fume generated during the welding process, and also by the surface condition of weldments. In this study, a dual-electromagnetic sensor, which utilizes the induced current variation in the sensing coil due to the eddy current variation of the metal near the sensor, was developed for arc welding of sheet metal I-butt joints. The dual-electromagnetic sensor thus detects the offset displacement of weld line from the center of sensor head even though there's no clearance in the joint. A set of design variables of the sensor was determined far the maximum sensing capability through the repeated experiments. Seam tracking is performed by correcting the position of sensor to the amount of offset displacement every sampling period. From the experimental results, the developed sensor showed the excellent capability of weld seam detection when the sensor to workpiece distance is near less than 5 ㎜, and it was revealed that the system has excellent seam tracking ability for the I-butt joint of sheet metal.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.236-236
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• 2009

This paper describes the fabrication and characteristics of Schottky micro hydrogen sensors for high temperatures by using polycrystalline(poly) 3C - SiC thin film grown on Si substrates with thermal oxide layer using APCVD. Pd/poiy 3C-SiC Schottky diodes were made and evaluated by I-V and C-V measurements. Electric current density and barrier height voltage were $2\times10^{-3}\;A/cm^2$ and 0.58 eV, respectively. These devices could operate stably at about $400^{\circ}C$. According to $H_2$ concentrations, their barrier height($\Phi_{Bn}$) were changed 0.587 eV, 0.579 eV, 0.572 eV and 0.569 eV, respectively. the current was increased. Characteristics of implemented sensors have been investigated in terms of sensitivity, linearity of response, response rate and response time. Therefore, from these results, Pd/poly 3C-SiC Schottky devices have very high potential for high temperature chemical sensor applications.

• Transactions on Electrical and Electronic Materials
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• 제14권5호
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• pp.273-277
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• 2013

A unified potentiostat circuit for both $O_2$- and $H_2O_2$- based electrochemical glucose sensors was proposed and its function was verified by circuit simulations and measurement results of a fabricated chip. This circuit consisted of an operational amplifier, a comparator and current mirrors. The proposed circuit was fabricated with a $0.13{\mu}m$ thick oxide CMOS process and an active area of $360{\mu}m{\times}100{\mu}m$. The measurements revealed an input operation range from 0.5 V to 1.6 V in the $H_2O_2$- based bio-sensor and from 1.7 V to 2.6 V in the $O_2$- based bio-sensor with a supply voltage of 3.3 V. The evaluation results showed that the proposed potentiostat circuit is suitable for measuring the electrochemical cell currents of both $O_2$- and $H_2O_2$- based glucose sensors.

• Journal of Advanced Marine Engineering and Technology
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• 제23권3호
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• pp.292-299
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• 1999

DC motors are widely used in many industrial fields as the actuator of the robot and the driving power motors of the electrical vehicle, Usually in the sensors of DC motors such as the encoder the tachogenerator and the potentiometer etc. are applied, But usage of these sensors results in the increased price and operating cost such that the application of the motors are limitted. To solve this problem another method to construct low cost control system is investigates. In this paper a new speed control method for DC motor is proposed. This method uses motor parameters instead of using speed or position sensors. In this way the angular velocity is estimated by the measure-ment values of the armature voltage and current instead of measuring the sensor signal. This paper presents an alorithm for estimating the angular velocity of DC motor The effectiveness of the proposed method is verified by experimental results. Also the applicability of the proposed method is presented by applying to the velocity contol of a wheeled mobile robot.