• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.606-608
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• 1989

Force/torque sensors are now providing widespread practical solutions to manufacturing problems, particularly in the area of automated assembly. The current state of the industry is discussed, including the evolution of transducer and controller design, and the trend of robot manufacturers to integrate force/torque sensors into their robot systems thereby greatly improving cycle time and simplifying the application development task for the end-user. Current and future application areas are discussed as well as the benefits of force/torque sensing.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.1
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• pp.40-47
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• 2003

A low-cost current-sensing scheme for the motor drives with MOSFET is described. Many motor drives usually employ the common current sensors to measure current for the purpose of control or protection. These current sensors, however, significantly burden the power circuit with the size and cost. The proposed current-sensing scheme utilizes information concerning MOSFET's On-voltage and On-resistance. An analogue circuit detecting On-voltage can overcome the above disadvantages because the circuit is small and is made at a low cost, and the fuzzy inference for On-resistance is also simply designed based on MOSFET's characteristics. The validity of this scheme will be experimentally verified by adopting the current control of a battery car.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.2
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• pp.123-129
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• 2000

This paper proposes a novel current control method of three-phase PWM rectifiers using estimated currents without phase current sensors. The phase currents are reconstructed from switching states of the rectifier and the measured dc output currents. To eliminate the calculation time delay effect of the microprosessor, the current at the next sampling instant are predicted by a predictive state observer and then are used for feedback control. Experimental results show that the control performance of the proposed system is almost the same as that of the phase current sensor-based system.

• Journal of Sensor Science and Technology
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• v.8 no.6
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• pp.434-439
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• 1999

Differential field effect transistors with double gate metal for integrated humidity sensors have been fabricated and the drain current drift characteristics to relative humidity have been investigated. The aspect ratio was 250/50 for both transistors to get the current difference between the sensing device and non-sensing one. The normalized drain current of the fabricated humidity sensitive field effect transistors increases from 0.12 to 0.3, as relative humidity increases from 30% to 90%.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.5
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• pp.404-411
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• 2020

Inductive power transfer (IPT) systems for electric vehicles generally require zero phase angle (ZPA) frequency tracking control to achieve high efficiency. Current sensors are used for ZPA frequency tracking control. However, the use of current sensors causes several problems, such as switching noise, degrading control performance, and control complexity. To solve these problems, this study proposes ZPA frequency tracking control without current sensors. Such control enables ZPA frequency tracking without real-time control and achieves stable zero voltage switching operation closed to ZPA frequency within all coupling coefficient and load ranges. The validity of the proposed control algorithm is verified on LCCL-S topology with a 3.3 kW rating IPT experimental test bed. Simulation verification is also performed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8306-8313
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• 2015

Open-type current sensors have been commonly used for DC motor controller, AC variable controller and Uninterruptible Power Supply. Recently they have begun to be used more widely, as the growth of renewable energy and smart-grid in power system. Considering most of the open-type current sensors are imported, developing the core technology needed to produce open-type current sensors is required. This paper describes the development and test results of open-type current sensors. Design of C type magnetic core, selection and test of a Hall sensor, design of current source circuit and signal conditioning circuit are described. 100A class DIP(Dual In-line Package) type and SMD(Surface Mount Devide) type open-type current sensors was made and tested. Test results show that the developed open-type current sensor satisfies the accuracy requirement of 2% and linearity requirement of 2% at 100 A of DC and AC current of 60Hz. Temperature compensation was carried out by using a temperature compensation circuit with NTC(Negative Temperature Coefficient) thermistor and the effect of the temperature compensation are described.

• Journal of Sensor Science and Technology
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• v.24 no.3
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• pp.194-201
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• 2015

The current sensor is used in industrial devices and power utilities. Core materials of these current sensors are divided into mainly two groups as silicon steel and fermalloy. Silicon steel has a wide saturation bandwidth but low sensitivity during low-current, whereas permalloy has a short saturation bandwidth but high sensitivity during low-current. In this paper, laminated silicon steel and permalloy by equal ratio is proposed to improve the linearity and saturation of current sensor. It is proved that the proposed core material has larger bandwidth than fermalloy as well as higher sensitivity than silicon steel. When comparing simulation results by FLUX 3D, the proposed method has also better performance than the previous core materials.

• Journal of Power Electronics
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• v.11 no.6
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• pp.931-937
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• 2011

This paper presents a method for the performance improvement of a shunt active power filter (SAPF) using the indirect current control (ICC) scheme. Compared to the conventional direct current control (DCC) scheme, the ICC gives better performance with a lower number of sensors. A simplified and efficient control algorithm using a low cost Intel 80C196KC microcontroller is implemented using only two current sensors for the source current and one voltage sensor for the DC-link voltage of the SAPF circuit. The objective is to eliminate harmonics and to compensate the reactive power produced by non-linear loads such as an uncontrolled rectifier feeding an inductive load. The APF is realized using a three phase voltage source inverter (VSI) with a dc bus capacitor. Experimental results are presented to prove the better performance of the ICC method over the DCC one.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.21-32
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• 2003

Developments and applications of the structural health monitoring (SHM) systems have become active particularity for long-span bridges in Korea. They are composed of sensors, data acquisition system, data transmission system, information processing, damage assessment, and information management. In this paper, current status of research and application activities on SHM systems for civil infra-structures in Korea are briefly introduced by 4 parts: (1) current status of bridge monitoring systems on existing and newly constructed bridges, (2) research and development activities on smart sensors such as optical fiber sensors and piezo-electric sensors, (3) structural damage detection methods using measured data, and (4) a test road project for pavement design verification and enhancement by the Korea Highway Corporation. Finally the R＆D activities of a new engineering research center entitled Smart Infra-Structure Technology Center at Korea Advanced Institute of Science and Technology are also briefly described.

• Journal of Korea Multimedia Society
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• v.10 no.10
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• pp.1260-1270
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• 2007

Testing and diagnosis of analog circuits(or mixed-signal circuits) continue to be a hard task for test engineers and efficient test methodologies to solve these problems are needed. This paper proposes a novel analog circuits test technique using time slot specification (TSS) based built-in current sensors (BICS). A technique for location of a fault site and separation of fault type based on TSS is also presented. The proposed built-in current sensors and TSS technique has high testability, fault coverage and a capability to diagnose catastrophic faults and parametric faults in analog circuits. In order to reduce time complexity of test point insertion procedure, external output and power nodes are used for test points and the current sensors are implemented in the automatic test equipment(ATE). The digital output of BICS can be easily combined with built-in digital test modules for analog IC test.