Papers by Keyword: Temperature Sensor

Abstract: SiC GTOs, with high current handling capability, are promising for high-voltage and high-power applications, but they also have temperature-related reliability issues, so real-time junction temperature monitoring is needed. In this paper, a novel 4H-SiC gate turn-off thyristor (GTO) structure with integrated temperature sensor is proposed. The proposed sensor is compatible with the SiC GTO process and allows for real-time temperature monitoring. TCAD simulation results show that the integrated sensor has a high sensitivity of 1.64mV/K and linearity of 0.99891, the temperature sensor monitors the internal temperature of the GTO device in real time with an error of no more than 2 K during complete GTO switching. This new structure is conducive to enhancing the reliability of SiC thyristor applications and system miniaturization.

Abstract: Fault protection of AC and DC network using semiconductors requires accurate electrothermal design of active and passive devices to keep power losses low in nominal condition and to sustain high current overload. Using SiC MOSFET for SSPC arises challenges to keep power losses low and to ensure robustness versus abnormal operating condition. Indeed, unpredictable events can dramatically damage the device integrity such as current overload, short-circuit... To overcome those issues, ones are generally carefully design driving system, implementing sensors and fast digital control circuit computing to sense simultaneously current, voltage and temperature, to analyze and detect abnormal operating condition. To reduce the whole detection transmission and reaction chain, we have designed a 1200V ; 30A ; 65mΩ instrumented SiC MOSFET, including both a current mirror and a temperature sensor in the active area of the die. This paper reports for the first-time real-time SiC instrumented MOSFET temperature and current measurement without the need of external sensors nor estimators.

Abstract: In this paper we study and compare two designs of a temperature sensor monolithically integrated to a vertical SiC JFET. One sensor utilizes the standard JFET P+ aluminum gate implantation scheme. The advantage of this sensor is that the integration with a JFET process flow can be achieved with no additional process steps or mask layers. The other sensor uses a combination P-body and a low energy P+ implantation scheme, typically seen in MOSFETs. Both sensors exploit the variation of resistance with temperature of Al doped SiC. Drift-Diffusion simulations of both designs are carried out at fixed temperatures, exhibiting an excellent ~53% relative reduction in sensor resistance from 300 to 450K. However, neither design shows linear behavior with temperature, beginning to saturate at 450K. Electrothermal simulations are also deployed to verify the sensor robustness as the sensor is locate relatively far from the JFET junction. Due to the high thermal conductivity of SiC, the sensor average temperature follows closely the junction temperature. Current crowding (or 2D effects) close to the contact edges is observed in both sensors. We also deploy a simple analytical model to calculate the resistance as a function of the temperature for both sensors. The model agrees with the drift-diffusion calculations, however due to the 2D nature of current flow, a maximum 19.6% relative error is obtained. In general, both sensors deployed similar relative sensitivity, however the P-body sensor resistance changes in a range of 10.6kΩ to 4.95kΩ compared to 700Ω to 330Ω for the P+ sensor.

Abstract: This research aims to design a human body temperature detection system based on the Internet of Things (IoT) and featuring the output with human voice. The implementation of the IoT concept using the MQTT Protocol. The stages in developing this system are needs analysis, design, develop, testing and evaluation. Principally, this system works as follows, once the temperature sensor detects a human temperature, the microcontroller will process this temperature data (1) convert the data into human voice and (2) sending (publish) the data to a web server in the internet. In this research uses Adafruit.com as Mqtt broker. Anyone subscribes to the feeds of the Adafruit will receive such temperature data automatically. To determine the output of the human temperature we must adjust with +3 from the original result of MLX90614 in the normal room temperature. By this adjustment we have the best of error average 0.96% and an average difference of result 0.35°C. It means, by adjustment +3 from the original result of the sensor will conform with the standards of IEC No. 13B-23 and the 13th revision of Melexis in 2019, where the maximum of error tolerance is 5% and the temperature difference is 0.5°C. For distance testing, the result is that the farther the object from the MLX90614 sensor will result the greater errors value and the object closer to the sensor, will result the smaller error. The average delay time to send data to the Adafruit Webserver and android application is 1.53 seconds.

Abstract: Zinc oxide nanorods zinc oxide nanowire has been deposited on quartz employing a hydrothermal method. The ZnO nanoroad as a seed layer were prepared for the growth process using the drop-casting method. The zincoxide nanomaterials produced were characterized by UV–Visible spectrophotometers, x-ray diffraction, Scanning electron microscopy ,. The crystal structure was calculated from the XRD data and it was confirmed the growth of wurtzite crystalline crystal structures of ZnO NRs. The SEM images revealed high-density nanowires were grown via drop cast coated seed layer. The bandgap in the ZnO NRs film was found to be 3.28 eV. This result was confirmed the formation of ZnO nanostructure. The thermal and electrical properties of ZnO NRs were measured also and analyzed. The conductivity of the ZnO NRs film was modified with the addition of gold nanoparticles using the sputtering technique. These modified films were promising and give an optimized temperature sensor performance.

Abstract: A high performance flexible temperature sensor for environmental and health monitoring has been fabricated using various combinations of composite blend of poly vinylidene fluoride / poly (3,4-ethylenedioxythiophene)-poly (styrenesulfonate) (PVDF/PEDOT:PSS). The response curves and working principle were investigated and sensors were then fabricated to achieve highly linear and stable response for a wide range of temperature sensing (25°C to 120°C). The film was fabricated on flexible polyethylene terephthalate (PET) substrate using spin coating. The copper electrodes were fabricated using copper tape. The sensors showed stable and close to linear response of impedance change by varying temperature in the range 25°C to 120°C. The resistance of the sensors changed from ~70MΩ to ~52MΩ for the temperature change in the range 25°C to 120°C. The sensors are aimed to replace low performance, complex and expensive sensors in the market for environmental and health monitoring applications.

Abstract: Temperature sensors are widely used in different industrial and scientific applications. These sensors commercially available in various type and configurations allow the enhancement of automotive systems. The manufactures need to improve and upgrade the technology by research activities regarding the accuracy of temperature measuring using sensors. In this paper will analyze the trends, applications and technologies in automotive temperature sensors. PTC/NTC thermistors are measured and characteristics curves are determined as expression of mathematical functions.

Abstract: The first HTSC alternators developed and tested mainly contained the bulks on the rotor. The presentation covers the problem of HTSC bulks magnetizing control in an assembled cryogenic alternator with axial flux. Cylindrical bulks are positioned on the rotor of a synchronous machine and form a multi-pole excitation system. The trapped magnetic field may vary under a number of processes, magnetic flux creep included. A special system to control the value of bulk magnetization and the temperature in the cryogenic zone is developed. Similar system may by applied in cryogenic disc-type alternators with permanent magnets on the rotor.

Abstract: The usability of 4H-SiC pin-diodes as nearly linear temperature sensors up to 800 K is demonstrated. Two sensor concepts were evaluated including the constant current forward bias (CCFB) concept and the integrated proportional to absolute temperature (PTAT) concept. The maximum sensitivity was 4.5 mV/K for the CCFB and an applied current density of 118 nA/cm². Additionally, this device can be used for UV detection, too, demonstrating the feasibility of 4H-SiC multi-sensor integration.

Abstract: Different characterization techniques have been used in order to evaluate the electrical behavior of Pt/SiC-Schottky diodes and determine their capability as temperature sensors. I-V characteristics for fabricated devices were measured up to 400°C. Subsequent conventional parameter extraction evinced a barrier height increase with temperature, suggesting inhomogeneous contact formation. The energy activation method was carried out in order to identify both the effective barrier height for the devices and the non-uniformity parameter (p). Despite severe degrees of contact inhomogeneity, the diodes were found adequate for temperature sensing applications over the 26°C – 400°C range, with sensitivities up to 1.59 mV/°C.