• Title/Summary/Keyword: Loop sensor

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Maximum Power Point Tracking without Current Sensor for Small Scale Photovoltaic Power System

  • Kasa Nobuyuki;Iida Takahiko;Majumdar Gourab
    • Proceedings of the KIPE Conference
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    • 2001.10a
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    • pp.631-634
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    • 2001
  • This paper presents a maximum power point tracking without a current sensor for a small scale photovoltaic power system. The small scale photovoltaic power systems are used in parallel, and so the cost and the reliability are strongly demanded. In the proposed inverter, the current is controlled with open loop, and then the power of photovoltaic array is calculated by the equation using the voltage of the photovoltaic array. Therefore, the system can obtain the power by detecting only the voltage of the photovoltaic array. As a result, we may obtain the performance of the MPPT with a current sensor as well as with a current sensor.

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A Study on the Remote Detection of a Hydraulic Cylinder Stroke Using Optical Fiber Sensors (광파이버센서를 이용한 유압실린더 스트로크의 원격 검출에 관한 연구)

  • 김인환;김종화
    • Journal of Advanced Marine Engineering and Technology
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    • v.25 no.1
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    • pp.191-198
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    • 2001
  • In order to comprise a basic closed-loop control system for hydraulic systems it is necessary to detect the piston rod stroke of a hydraulic cylinder. There are many conventional type sensors which can detect the displacement of cylinders. However, they cannot reveal the original performance normally or they cannot be applied at all where the operating circumstance of cylinders is beyond specifications of sensors. Especially, for the purpose of detecting the strokes of cylinders mounted on heavy equipments, a special exclusive sensor must be used because the operating circumstances of heavy equipments are so severe that general purpose sensors cannot endure such circumstance as shock and a residual vibration induced by rough works. In this paper, an exclusive method for detecting the piston rod stroke for heavy equipments is suggested, which adopts a remote detecting technique using optical fiber sensors. Several experiments using the prototype are executed for verifying the effectiveness of the suggested method and the possibility of the accurate detection of stroke.

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Realization of Communication and Sensor Signal Processing Technique for Condition Monitoring of Check Valve (Check Valve 상태감시를 위한 통신 및 센서신호처리 기능 구현)

  • Jeon, Jeong-Seop;Jo, Jae-Geun;Kim, Jeong-Su;Yu, Jun
    • Proceedings of the KIEE Conference
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    • 2003.11b
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    • pp.223-226
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    • 2003
  • This paper presents a realization of sensor signal processing(noise filtering) and Fieldbus based communication for condition monitoring of check valve. we first acquired the AE(Acoustic Emission) sensor data at the KAERI check valve test loop, and their frequencies were analyzed to find the informative band. To reject background noises, bandpass filters have been designed. Also, to send the processed data to a remote site, wired communication facility has been realized via DeviceNet.

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PID and adaptive learning control for engine air-fuel control system (PID 및 적응학습 제어기법을 이용한 자동화 엔진의 공기-연료비 제어시스템 연구)

  • Lee, Deong-Kyoo;Choi, Don;Woo, Kwang-Bang
    • 제어로봇시스템학회:학술대회논문집
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    • 1990.10a
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    • pp.658-662
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    • 1990
  • In the air-fuel control of automotive engine to improve its efficiency, fuel economy and less emissions, conventional control methods using $O_{2}$ sensor or the lean air-fuel ratio sensor provide only open control in rich conditions. Control with a wide range air-fuel sensor makes it possible to employ closed loop control for all engine conditions including rich combustion. With a wide range A/F sensor and A/F transfer functions, a PID control system is constructed which employs an learning scheme. A/F controller is designed which enables to improve the ability of its compensation for sensors and actuators, and its control operation is evaluated by computer simulation.

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A Method on the Temperature Compensation for the Oxygen Electrode for DO Sensor (DO 센서용 산소전극의 온도보상에 대한 일 방안)

  • Rhie, Dong-Hee;Choi, Bok-Gil
    • Proceedings of the KIEE Conference
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    • 1995.11a
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    • pp.376-378
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    • 1995
  • A method is presented for the design and fabrication of the temperature compensation circuits on the Clark electrodes for measuring the dissolved oxygen(DO) concentration. The discussion includes a method of the sensor interface circuits for the DO sensor. Typical polarograms for the DO probes under test using this sensor circuits are presented. High accuracy over 99 % of the I to V conversion using the proposed circuit is verified. Temperature dependence for the test DO probe is well compensated automatically using the thermistor($2k\Omega,\;25^{\circ}C$) in series with correction resistor in the feedback loop of the op-amp circuit in the temperature range of the 0-50$^{\circ}C$.

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Clamp-type Bulk Optic Current Sensor (클램프헝 부피 광 전류센서)

  • Chung, Hyun;Lee, Yong-Wook;Kim, Soo-Gil;Lee, Byoung-Ho;Park, Byoung-Seok
    • Proceedings of the KIEE Conference
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    • 2002.07c
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    • pp.1924-1926
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    • 2002
  • The optical current transformer using Faraday effect is the sensor to measure current that flows in any conductor. This sensor doesn't undergo the magnetic saturation and effect of adjacent conductors. But this senor using bulk-glass sensing clement has crucial drawback. It is impossible that the sensor is mounted to conductor without breaking the closed-loop of light or conductor. So we developed the clamp-type optical current transformer and made an experiment.

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Temperature Compensation of Hot-film Flow Sensor (박막 히터형 유량센서의 온도보상)

  • Kim, Hyung-Pyo
    • Journal of Sensor Science and Technology
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    • v.9 no.4
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    • pp.268-273
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    • 2000
  • This paper represents a hot-film flow sensor which is compensated by a noble temperature compensation method using the initial unbalanced voltage. The resistance value of the sensor is determined by using the graph of the initial unbalanced voltage of an open-loop circuit against the air temperature. The compensation is accomplished by applying the unbalanced ratio of the resistors in the Wheastone bridge circuit. In the range of air temperature of $-20^{\circ}C{\sim}120^{\circ}C$, the error is about ${\pm}1%$.

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Sensor Placement in Structural Vibration Control For the Performance of Modal Filter (모달필터 성능을 고려한 센서의 최적위치)

  • 황재혁;김준수;백승호
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1997.04a
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    • pp.308-315
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    • 1997
  • In this study, the effect of modal filter error on the vibration control characteristics of flexible structures is analyzed for IMSC(Independent Modal Space Control), and optimal sensor placement in the structural vibration control with consideration of performance of modal filter has been studied. An Lyapunov asymptotic stability condition has been derived, which depends on the magnitude of the modal filter errors. The extent of the response deviation of the closed-loop system is also derived and evaluated using operator techniques. A sensor placement technique has also been suggested to maximize the performance of the modal filter. It has been found by a series of simulation that the suggested sensor placement technique is very effective on the determination of the number and placement of sensors of modal filter in the structural vibration control.

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Estimation Technique of Fixed Sensor Errors for SDINS Calibration

  • Lee, Tae-Gyoo;Sung, Chang-Ky
    • International Journal of Control, Automation, and Systems
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    • v.2 no.4
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    • pp.536-541
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    • 2004
  • It is important to estimate and calibrate sensor errors in maintaining the performance level of SDINS. In this study, an estimation technique of fixed sensor errors for SDINS calibration is discussed. First, the fixed errors of gyros and accelerometers, excluding gyro biases are estimated by the navigation information of SDINS in multi-position. The SDINS with RLG includes flexure errors. In this study, the gyros flexures are out of consideration, but the proposed procedure selects certain positions and rotations in order to minimize the influence of flexures. Secondly, the influences of random walks, flexures and orientation errors are verified via numerical simulations. Thirdly, applying the previous estimated errors to SDINS, the estimation of gyro biases is conducted via the additional control signals of close-loop self-alignment. Lastly, the experiments illustrate that the extracted calibration parameters are available for the improvement of SDINS.

Design of a Tag Antenna for UHF RFID Food Systems

  • Shin, Dong-Beom;Lee, Jung Nam;Lee, Heyung-Sub;Lee, Sang-Yeoun;Kim, Byeong-Sam
    • Journal of electromagnetic engineering and science
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    • v.13 no.4
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    • pp.208-213
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    • 2013
  • This paper proposes a tag antenna for radio frequency identification (RFID) food system. The RFID tag antenna is designed and fabricated based on the rectangular loop concept used in the UHF band (Korean and Japanese standards, 916.7-923.5MHz). The proposed tag antenna is composed of a radiation patch, sensor tag chip, temperature sensor, oscillator, and battery. We conjugated matching between the tag antenna and the sensor tag using a U-shaped stub. Details of the proposed tag antenna design and the simulated and measured results are presented and discussed.