The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform

Jhih-cheng You - One of the best experts on this subject based on the ideXlab platform.

  • Temperature-to-Frequency Converter With 1.47% Error Using Thermistor Linearity Calibration
    IEEE Sensors Journal, 2019
    Co-Authors: Chua-chin Wang, Zong-you Hou, Jhih-cheng You
    Abstract:

    Temperature variation is well known to be very critical for estimating other parameters, e.g., the state of charge and the state of health of batteries. A high-accuracy temperature to frequency converter with thermistor linear calibration based on the thermistor linearization circuit is designed and analyzed in this investigation, where a voltage-to-frequency converter (VFC) is added instead of an analog-to-digital converter. The proposed design converts the voltage into a digital signal (frequency output) to reduce design complexity as well as the cost of chip area. A detailed analysis, including the method using the thermistor linearization calibration circuit and VFC, is reported in this paper. The measurement results in a Thermal Chamber establish that the output frequency is 1.62 to 2.27 MHz, the maximum linearity error is ±0.5%, and the temperature error is ≤1.47% in the temperature range of 268.15 to 313.15 K.

  • A High-Precision CMOS Temperature Sensor with Thermistor Linear Calibration in the (-5 °C, 120 °C) Temperature Range.
    Sensors, 2018
    Co-Authors: Chua-chin Wang, Zong-you Hou, Jhih-cheng You
    Abstract:

    A high-precision Complementary Metal-Oxide-Semiconductor (CMOS) temperature sensor for (−5 °C, 120 °C) temperature range is designed and analyzed in this investigation. The proposed design is featured with a temperature range selection circuit so that the thermistor linear circuit automatically switches to a corresponding calibration loop in light of the temperature range besides the analysis of the calibration method. It resolves the problem that the temperature range of a single thermistor temperature sensor is too small. Notably, the output of the proposed design also attains a high linearity. The measurement results in a Thermal Chamber justifying that the output voltage is 1.96 V to 4.15 V, the maximum linearity error ≤1.4%, and the worst temperature error ≤1.1 °C in the temperature range of −5 °C to 120 °C.

Chang Gyun Kim - One of the best experts on this subject based on the ideXlab platform.

  • Simultaneous measurement of strain, temperature and vibration frequency using a fibre optic sensor
    Measurement Science & Technology, 2002
    Co-Authors: H K Kang, H J Bang, C S Hong, Chang Gyun Kim
    Abstract:

    In this paper, a novel technique for the simultaneous measurement of strain, temperature and vibration for structural health monitoring is demonstrated using a fibre optic sensor system, which combines both a wavelength-swept fibre laser (WSFL) system and a laser diode system using a wavelength division multiplexer. An aluminium beam was placed in a Thermal Chamber for the simultaneous measurement of its strain, temperature and vibration characteristics. A fibre Bragg grating/extrinsic Fabry-Perot interferometer (EFPI) hybrid sensor system with WSFL was used for the strain and temperature measurements, while the EFPI sensor in the hybrid sensor operated by a laser diode simultaneously measured the vibration characteristics of the beam.

Chua-chin Wang - One of the best experts on this subject based on the ideXlab platform.

  • Temperature-to-Frequency Converter With 1.47% Error Using Thermistor Linearity Calibration
    IEEE Sensors Journal, 2019
    Co-Authors: Chua-chin Wang, Zong-you Hou, Jhih-cheng You
    Abstract:

    Temperature variation is well known to be very critical for estimating other parameters, e.g., the state of charge and the state of health of batteries. A high-accuracy temperature to frequency converter with thermistor linear calibration based on the thermistor linearization circuit is designed and analyzed in this investigation, where a voltage-to-frequency converter (VFC) is added instead of an analog-to-digital converter. The proposed design converts the voltage into a digital signal (frequency output) to reduce design complexity as well as the cost of chip area. A detailed analysis, including the method using the thermistor linearization calibration circuit and VFC, is reported in this paper. The measurement results in a Thermal Chamber establish that the output frequency is 1.62 to 2.27 MHz, the maximum linearity error is ±0.5%, and the temperature error is ≤1.47% in the temperature range of 268.15 to 313.15 K.

  • A High-Precision CMOS Temperature Sensor with Thermistor Linear Calibration in the (-5 °C, 120 °C) Temperature Range.
    Sensors, 2018
    Co-Authors: Chua-chin Wang, Zong-you Hou, Jhih-cheng You
    Abstract:

    A high-precision Complementary Metal-Oxide-Semiconductor (CMOS) temperature sensor for (−5 °C, 120 °C) temperature range is designed and analyzed in this investigation. The proposed design is featured with a temperature range selection circuit so that the thermistor linear circuit automatically switches to a corresponding calibration loop in light of the temperature range besides the analysis of the calibration method. It resolves the problem that the temperature range of a single thermistor temperature sensor is too small. Notably, the output of the proposed design also attains a high linearity. The measurement results in a Thermal Chamber justifying that the output voltage is 1.96 V to 4.15 V, the maximum linearity error ≤1.4%, and the worst temperature error ≤1.1 °C in the temperature range of −5 °C to 120 °C.

H K Kang - One of the best experts on this subject based on the ideXlab platform.

  • Simultaneous measurement of strain, temperature and vibration frequency using a fibre optic sensor
    Measurement Science & Technology, 2002
    Co-Authors: H K Kang, H J Bang, C S Hong, Chang Gyun Kim
    Abstract:

    In this paper, a novel technique for the simultaneous measurement of strain, temperature and vibration for structural health monitoring is demonstrated using a fibre optic sensor system, which combines both a wavelength-swept fibre laser (WSFL) system and a laser diode system using a wavelength division multiplexer. An aluminium beam was placed in a Thermal Chamber for the simultaneous measurement of its strain, temperature and vibration characteristics. A fibre Bragg grating/extrinsic Fabry-Perot interferometer (EFPI) hybrid sensor system with WSFL was used for the strain and temperature measurements, while the EFPI sensor in the hybrid sensor operated by a laser diode simultaneously measured the vibration characteristics of the beam.

Almir Ahmethodzic - One of the best experts on this subject based on the ideXlab platform.

  • criteria for successful short circuit current interruption on a real 245 kv 40 50 ka sf6 circuit breaker
    International Conference on Electric Power Equipment – Switching Technology, 2015
    Co-Authors: Mahir Muratovic, Mirsad Kapetanovic, Amer Smajkic, Almir Ahmethodzic
    Abstract:

    Special attention needs to be given to the processes that occur in alternating current arcs at the instant when the current naturally passes through a zero. The short interval of time around current zero, named the "interaction period" [1], is of crucial importance for arc-quenching, when it is decided whether the interruption will be definite or whether arc reignition will occur. As a matter of fact, regardless of the SF6 circuit breaker working principle, its rated voltage and history of the short circuit current interruption process, there is a critical value of arc extinction voltage peak which must be reached to make a successful interruption possible [2]. The arc extinction voltage peak can be increased by elongating the arc (in other words by increasing the distance between arcing contacts) and/or by increasing the pressure of SF6 gas inside the Thermal Chamber around current zero instant. This means that it is possible to find a critical value of distance between arcing contacts and a critical value of SF6 gas pressure inside the Thermal Chamber at current zero instant as criteria for successful short circuit current interruption. Based on the results of type tests in high power laboratory (including current zero measurement — CZM) and the calculation results of the software HV CB Simulation, these criteria for short circuit current interruption are successfully established for a real SF6 circuit breaker 245 kV 40/50 kA.

  • Criteria for successful short circuit current interruption on a real 245 kV 40/50 kA SF6 circuit breaker
    2015 3rd International Conference on Electric Power Equipment – Switching Technology (ICEPE-ST), 2015
    Co-Authors: Mahir Muratovic, Amer Smajkic, Kyong-hoe Kim, Myoung-hoo Kim, Mirsad Kapetanović, Almir Ahmethodzic
    Abstract:

    Special attention needs to be given to the processes that occur in alternating current arcs at the instant when the current naturally passes through a zero. The short interval of time around current zero, named the "interaction period" [1], is of crucial importance for arc-quenching, when it is decided whether the interruption will be definite or whether arc reignition will occur. As a matter of fact, regardless of the SF6 circuit breaker working principle, its rated voltage and history of the short circuit current interruption process, there is a critical value of arc extinction voltage peak which must be reached to make a successful interruption possible [2]. The arc extinction voltage peak can be increased by elongating the arc (in other words by increasing the distance between arcing contacts) and/or by increasing the pressure of SF6 gas inside the Thermal Chamber around current zero instant. This means that it is possible to find a critical value of distance between arcing contacts and a critical value of SF6 gas pressure inside the Thermal Chamber at current zero instant as criteria for successful short circuit current interruption. Based on the results of type tests in high power laboratory (including current zero measurement - CZM) and the calculation results of the software HV CB Simulation, these criteria for short circuit current interruption are successfully established for a real SF6 circuit breaker 245 kV 40/50 kA.

  • Nozzle ablation model: Calculation of nozzle ablation intensity and its influence on state of SF 6 gas in Thermal Chamber
    2013 IEEE International Conference on Solid Dielectrics (ICSD), 2013
    Co-Authors: Mahir Muratovic, Mirsad Kapetanovic, Almir Ahmethodzic, Sead Delic, Wang Byuck Suh
    Abstract:

    Energy released by electric arc during short circuit switching is mostly absorbed by the surrounding cold SF6 gas. However, a considerable part of this energy is also transferred and absorbed by other elements of the circuit breaker interrupter which are located near the electric arc. The most important parts are the transfer of energy to the arcing contacts and to the nozzles, absorption of the energy by these elements and the resulting effects. The absorption of the energy causes heating, melting and finally the vaporization of structural material and it is the main cause of wearing of arcing contacts and nozzles, where the latter is commonly referred to as the nozzle ablation. The nozzle ablation causes an increase in the nozzle throat diameter which generally has a negative effect on the circuit breakers breaking performance. The other significant effect is the mixing of SF6 gas and the nozzle vaporized material in the nozzle space and in the surrounding Chambers. It is obvious that the ablation process has a considerable influence on the state of SF6 gas in the contact gap but also in the adjacent interrupting Chambers, in particular on the state of gas in the Thermal Chamber in case of self-blast interrupting units. In this paper, a method of calculation of intensity of nozzle ablation is presented as well as a variety of calculation results. The calculated nozzle ablation intensity is verified by comparing the calculated results of the nozzle diameter increase and mass losses, with experimentally obtained data. In addition to the nozzle ablation intensity, the influence of the ablated nozzle material on the state of SF6 gas in the Thermal Chamber is also analyzed and discussed. The model is incorporated into a computer application for high voltage circuit breaker interruption simulation.