Over-temperature Protection Research Articles

Design and Performance Evaluation of a Specialized Bubbler System for Accurate and Repeatable Solid Oxide Electrolysis Cell (SOEC) Testing

Accurate assessment of Solid Oxide Electrolysis Cell (SOEC) performance demands standardized testing conditions, particularly in stable steam delivery. Fluctuations in steam concentration and flow rate can significantly impact measured open-circuit voltage (OCV) and polarization behavior. Although direct steam injection is straightforward, it is often hindered by instability resulting from intermittent liquid water flux, pressure fluctuations, and fractional distillation effects. Bubbler humidification systems have the potential to offer consistent steam, but tailored designs for SOEC testing are currently absent.This study introduces a specialized bubbler system designed to deliver stable steam to SOEC test stands accommodating both oxygen-conducting (O-SOEC) and proton-conducting (H-SOEC) cells. The bubbler components include a refill water reservoir, a level control module, heating elements, pressure relief valves, check valves, tubing, and fittings integrated with the test stand. The system humidifies the sweep gas, transporting steam to the cell test fixture situated within a high-temperature furnace.The design process involved meticulous considerations of materials compatibility, hydrogen safety, and overtemperature protection. All wetted components employ stainless steel, glass, or PTFE materials in their construction construction. Redundant thermocouples ensure safe process temperatures with automated overtemperature shut off. The refill reservoir and bubbler headspace operate near ambient pressure, facilitated by an exhaust line vent sized for minimal backpressure.In various executed O-SOEC tests, the bubbler maintained OCV stability within ±5 mV over several hundred hours for each cell operating at 750°C, eliminating spikes caused by steam fluctuations observed with direct injection methods. This facilitates precise electrochemical analysis and determination of area-specific resistance losses. Polarization curves align with expected behavior based on the Nernst equation. The system has demonstrated safe and stable functionality for over thousands of hours across various operating conditions.The bubbler design presents researchers with notable advantages over existing steam supply options for SOEC test stands, addressing performance, safety, and flexibility concerns. Online instrumentation enables closed-loop control of steam conditions, enhancing stability. Standardization of test equipment is crucial for quality results, and this work contributes progress toward reproducible protocols in the international SOEC community. The modular bubbler approach, integrated with safety features, also signifies safer methodology choices for lab-scale experimental research.

A Novel Reliability-Enhanced Dual Over-Temperature Protection Circuit With Delayed Thermal Restart for Power ICs

A Novel Reliability-Enhanced Dual Over-Temperature Protection Circuit With Delayed Thermal Restart for Power ICs

A 5-μA Low Power Over-Temperature Protection Circuit With High Voltage and Process Stabilities for Line Driver in PLC Applications

This paper introduces a over-temperature protection (OTP) circuit used in line driver chip for PLC applications. For the limitations of the BJT process, the proposed circuit adopts a current distribution structure with a positive loop to realize state switching if the temperature exceeds the threshold or recovers, instead of the traditional structures with integrated comparators in the CMOS process. The method minimizes quiescent current (IQ) and transistor consumptions of the circuit. In addition, due to no comparator exists, there is no need for reference voltage, so that the process and voltage stabilities of the circuit are improved. The OTP circuit is implemented by SOI-BJT process, and relies on a line driver chip for verification. The module consumes 5-μA IQ, which only accounts for 0.02% of the whole chip. The measured maximum temperature drift of the circuit is 0.167 ∘C/V under the power supply voltage range of 6-30V, and the average hysteretic temperature drift of 6 random sampled chips is 0.15 ∘C.

Self-Adaptive Overtemperature Protection Materials for Safety-Centric Domestic Induction Heating Applications

Security aspects in the household sphere have become a major concern in modern societies. In particular, regardless of the technology used, users increasingly appreciate a protection system to prevent material damage in the case of human errors or distractions during the cooking process. This paper presents a sensorless method for detecting and limiting overtemperature, unique to induction cooktops, based on their specific features, such as automatic pot detection and load power factor estimation. The protection system exploits the change in the load material properties at certain temperatures, the effect of which may be enhanced by arranging a multilayer structure comprising a low Curie temperature alloy and an aluminum layer. The proposed multilayer load exhibits two differentiated states: a normal state, where the cookware is efficiently heated, and a protection state, above the safety temperature, where the power factor abruptly decreases, limiting the overheating and making the state easily detectable by the cooktop. This method of overtemperature self-protection uses the electronics of conventional induction cooktops; therefore, no other sensors or systems are required, reducing its complexity and costs. Simulation and experimental results are provided for several cookware designs, thereby proving the feasibility of this proposal.

Improved Temperature Monitoring and Protection Method of Three-Level NPC Application Based on Half-Bridge IGBT Modules

The overheating stress of power devices is the main cause of converter system failures, so real-time temperature acquisition, as well as timely over-temperature protection, under various operating conditions are key to achieving a more reliable energy conversion. In this paper, an improved three-dimensional (3-D) coupled thermal model for insulated gate bipolar transistors (IGBTs) and related heatsink is constructed by considering the thermal coupling effects at both the device- and the module level. Furthermore, the coupled thermal impedance parameters are thereby extracted based on the finite-element method (FEM), so that the dynamic loss and transient temperature distribution under actual working conditions can be obtained based on this electro-thermal coupling model. Meanwhile, to avoid the overheating damage of power devices due to untimely action of the negative temperature coefficient (NTC) thermistor over-temperature protection, this article aims at the idle IGBT device in the three-level neutral-point clamped (NPC) application using IGBT half-bridge modules, combined with the emitter terminal temperature, and finally realizes the multiple over-temperature protection settings. The improved temperature monitoring methods proposed in this paper are realized by the drive and control circuits and verified through simulation and experimental results.

Temperature-Aware Adaptive Control for Automotive Front-Lighting System

Adaptive front-lighting systems (AFSs) have been widely adopted to automotive industries for providing higher driver’s safety. As their light sources, multi-string light-emitting diodes (LED) arrays have been widely adopted because of their simpler driver controls. Recently, micro-structured AFSs (μAFSs) with a micro-LED (μLED) array are highly demanded for their controllability of individual LEDs. However, the integration of a μLED array and its high-power active-matrix driver are not available on the market. Moreover, a high-power driver causes not only a significant variation in driving current, but also a higher power density requiring over-temperature protection (OTP). In this paper, the average current through each μLED is adaptively controlled with pulse width modulation (PWM) in conjunction with an additional PWM control for temperature calibration. Experimental results with a 16 × 16 μLED array placed on top of the proposed driver show that a 5-bit PWM signal controls the average current through each μLED cell up to 11 mA. The maximum current error of 4.11% at 100 °C is reduced to 0.23%. When OTP is enabled, the amount of average pixel current reduction depends on the given temperature. The maximum power efficiency of the proposed μAFSs driver is as high as 92.3%.

In Situ Insulated Gate Bipolar Transistor Junction Temperature Estimation Method via a Bond Wire Degradation Independent Parameter Turn-OFF V ce Overshoot

Fast and accurate online monitoring of junction temperature of insulated gate bipolar transistor (IGBT) chips is of great significance for overtemperature protection and thermal stress optimization of IGBTs. However, existing IGBT junction temperature estimation methods have drawbacks of dependence on bond wire degradation, low resolution, nonlinearity, and difficulty in online implementation. In this article, a novel <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in situ</i> IGBT junction temperature estimation method via turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> collector voltage overshoot is proposed, which is independent on bond wire degradation. Based on theoretical analysis, the turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> collector voltage overshoot is approximately linear to the junction temperature. The peak value of the turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> collector voltage can be extracted during operation. Experiments are conducted to verify the technique proposed. A linear relationship between collector voltage overshoot and IGBT junction temperature is revealed, which illustrates the validity of the proposed method. Besides, the operation parameters (bus voltage, load current, and temperature) are considered, and the calibration on operation parameter variations is discussed. At last, the proposed method is compared with a traditional IGBT junction temperature estimation method based on the <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> -state voltage drop. The advantages of the proposed method lie in its independence on bond wire degradation and high resolution for online temperature estimation.

Design of New Over-Temperature Protection Light-Emitting Diode Driver Circuit and Improvement Method of Visual Design

The overall design of light-emitting diode (LED) display control system was completed at first. For the problems of LED driver chip such as low accuracy of constant current output, high power consumption, poor stability, and single over-temperature protection function, the double temperature hysteresis and over-temperature buffer protection function of circuit were designed. The low-power constant-current module of LED driver module included an operational amplifier, a MOS tube with negative feedback control, and the driving current required to achieve high-precision reference current conversion. The temperature control points were set in hysteretic and overtemperature buffer modules for the working temperature, and power MOS tube was turned off in time to reduce the driving current to a constant driving current, thus reducing the power consumption of circuit. In addition, to improve the image quality of LED display, a visual refresh logic circuit was designed. The display cycle was divided into 32 segments by logic circuit, with 128 gray clock cycles in each segment, and duty ratio was controlled by 12 bits of gray data. In test, the multi-value output bandgap reference voltage was simulated at first. In range of –30 °C–130 °C, the fluctuation of voltage in this temperature range met the requirements of circuit. During simulation of buffer circuit of the LED driver module, it was found that output terminal can perform good voltage following, so as to meet the needs of circuit. The design of visual refresh logic circuit can greatly improve the refresh rate of pulse width modulation (PWM).

Overtemperature-protection intelligent molecular chiroptical photoswitches

Stimuli-responsive intelligent molecular machines/devices are of current research interest due to their potential application in minimized devices. Constructing molecular machines/devices capable of accomplishing complex missions is challenging, demanding coalescence of various functions into one molecule. Here we report the construction of intelligent molecular chiroptical photoswitches based on azobenzene-fused bicyclic pillar[n]arene derivatives, which we defined as molecular universal joints (MUJs). The Z/E photoisomerization of the azobenzene moiety of MUJs induces rolling in/out conformational switching of the azobenzene-bearing side-ring and consequently leads to planar chirality switching of MUJs. Meanwhile, temperature variation was demonstrated to also cause conformational/chiroptical inversion due to the significant entropy change during the ring-flipping. As a result, photo-induced chiroptical switching could be prohibited when the temperature exceeded an upper limit, demonstrating an intelligent molecular photoswitch having over-temperature protection function, which is in stark contrast to the low-temperature-gating effect commonly encountered.

Overtemperature Protection Circuit for GaN Devices Using a di/dt Sensor

Power semiconductor devices have maximum junction temperature limits, but it is not straightforward to sense or infer temperature inside sealed devices in running converters. One method is to observe electrical behavior that is known to be temperature dependent. For example, in some gallium nitride (GaN) power semiconductor devices, the maximum slope of the device current at turn-on has been shown to reduce as the junction temperature increases. This article demonstrates the first noncontact overtemperature protection circuit for GaN power devices that exploits this effect and overcomes the complication that this inverse proportionality is affected by load current. A variant of a previously reported magnetic field “Infinity Sensor,” named after its figure-of-eight topology and high bandwidth (>200 MHz), measures di/dt. Using the sensor signal as the only input, a detection circuit finds peak di/dt, and a high-speed integrator derives instantaneous load current. The reference voltage for the decision-making part of the circuit is automatically adjusted as a function of load current, in order to counteract the dependence of di/dt on load current. Experimental results on a 400 V, 2 kW buck converter show the protection circuit successfully activating within ±5 °C of a preprogrammed junction temperature setting, independently of load current, for settings of 100, 120, and 140 °C.

Pengujian Keselamatan Thermal pada Battery Pack Sepeda Motor Listrik Berdasarkan Regulasi UN R-136

The electric-motorcycle is one of the promising technology that can improve environmental quality as well as reduce dependency on oil imports in Indonesia. The major challenge of electric-motorcycle implementation is the safety of the lithium-ion battery pack. This research aims to ascertain the over-temperature protection, and also to carry out shock &amp; cycling test for the battery thermal safety. The testing procedures and apparatus comply with the United Nations Regulation No 136 (UN R-136), namely a temperature humidity chamber, a battery load unit, a blower, and a charger. The first step is the designing and prototyping of the battery pack with 100 V and 30 Ah, which contains a module of cells, Battery Management System (BMS), wiring, isolator, socket, and aluminum casing. The second step is the battery thermal safety test. The results showed that the battery pack satisfied the acceptance criteria, with evidence of no electrolyte leakage, rupture, fire, and explosion during and after testing. Result of over-temperature protection, BMS can cut-off the discharge rate at a temperature of 45.89°C. Meanwhile, for thermal shock &amp; cycling tests, the battery pack did not fail when the temperature changes from 59.72°C and -40.25°C for 60 hours.

Resistivity-Temperature Behavior of Intrinsically Conducting Bis(3-methoxysalicylideniminato)nickel Polymer.

Materials with a positive temperature coefficient have many applications, including overcharge and over-temperature protection in lithium-ion (Li-ion) batteries. The thermoresistive properties of an electrically conductive polymer, based on a Ni(salen)-type backbone, known as polyNiMeOSalen, were evaluated by means of in situ resistivity measurements. It was found that the polymer was conductive at temperatures below 220 °C; however, the polymer increased in resistivity by three orders of magnitude upon reaching 250 °C. Thermogravimetric results combined with elemental analyses revealed that the switch from the insulation stage to the conductive stage resulted from thermally dedoping the polymer. Electrochemical studies demonstrated that a polymer retains its electroactivity when it is heated and can be recovered to a conductive state through oxidation via electrochemical doping in an electrolyte solution.

RETRACTED: Research on Thermal Insulation Performance of Energy-Saving Exterior Walls of Large Buildings Based on Wireless Sensors

Protection of current settings, worried about energy and help the global effort to improve global atmosphere costs, provide structure to the external divider structure of energy capacity. A significant step to increase. In this article, the method will see a gift survey to expand energy efficiency private construction aggregates, like the freezing point of research development of the surrounding structure, while further protecting the high refractive file's outer surface. Deflection runs another big passion, empty glass microspheres deflection and then run protection. Essential sepiolite Nanofibers have many Nanopores have a great passion. They have excellent enthusiasm run protection. Nan zinc serpentine oxide in the coating material promotes warm massive deflection operation and simplifies the silence bound to the cationic surface to improve the specialized level. Performance over-temperature protection and empty glass microspheres and sepiolite Nan fibers improved. In this context, the protective coating warm investigating effects are provided by three different variables: embodiment, useful fillers and warm total weight deflection value and overwrite protection, intricate patterns in three different variables. The results show that the cationic surface modifier oxide Nano zinc Fi preferably bound silage when the saline is 6%, which expert's expandable composition. the sound is increased Nano zinc oxides, the knitting empty glass microspheres, sepiolite Nanofibers alone, 3%, 4%, 4%, deflection and coating protection will be preferably carried out. Control and the protection cover and the control of a transparent material warm improvements, evaluated by increasing the maximum temperature ~13.5 C language distinction between the top and bottom surfaces

Turn-on Delay Based Real-Time Junction Temperature Measurement for SiC MOSFETs With Aging Compensation

Online junction temperature (T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">j</sub> ) measurement enables robust power converter operations by providing overtemperature protection and condition monitoring of the power devices. For SiC MOSFETs, the real-time T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">j</sub> information is especially critical as limited field data are available regarding the reliability. In this article, utilizing the turn-ON delay time as temperature sensitive electrical parameter, an online T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">j</sub> measurement is realized through an intelligent gate drive. Specifically, the turn-ON delay time is translated into the pulsewidth of a digital signal through the conditioning/logic circuits. During T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">j</sub> measurements, the adjustable gate resistance circuit is activated to improve the measurement sensitivity beyond 600 ps/°C. Using the high-resolution capture module (300-ps resolution) in the system microcontroller, this pulsewidth is measured and then converted to junction temperature with a resolution of <; 0.5 °C. A prototype is built to validate the online T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">j</sub> measurement method. The switching test results show that the circuit is able to precisely measure T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d,on</sub> and offers a good linearity/sensitivity for T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">j</sub> estimation. In the continuous operation, the junction temperature of a decapsulated device using an infrared camera and T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">j</sub> obtained from the circuit match well with <; 1 °C difference under various operating conditions. In addition, the gate-oxide degradation's impact on T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d,on</sub> is considered for SiC MOSFETs, and an aging compensation scheme is discussed to maintain the measurement accuracy throughout the device's lifetime. It is shown that the proposed circuit provides an accurate real-time T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">j</sub> measurement for SiC MOSFETs, which can be deployed to improve the power converters' reliability.

Over-Temperature-Protection Circuit for LED-Battery Power-Conversion System Using Metal-Insulator-Transition Sensor

Extracting renewable energy from solar and wind energy systems, fuel cells, and tidal power plants requires DC distribution and energy storage devices. In particular, a metal-insulator-transition (MIT) sensor can be applied to the over-temperature-protection (OTP) circuit, to stop the LED-battery power-conversion system when over-temperature occurs. Recently, there have been instances of battery systems catching fire because of poor battery design, over-charging, over-voltage, cell balancing failure, and an inadequate battery management system circuit. For continuous stabilization using an LED-battery power-conversion system, a 450 Wh class battery system that can monitor the temperature of battery packs with an MIT sensor was developed in this study. Furthermore, an OTP circuit involving an MIT sensor to protect LED-battery power-conversion systems is proposed. According to the results, this approach is required to continuously perform the stabilization of LED-battery systems.

Design of new quick control power protection system of EAST

Aiming at the problems that may arise in the work of the AC-DC-AC converter of the new fast-control power system of the Experimental Advanced Superconducting Tokamak (EAST), a control and protection method for each link is proposed. Based on in-depth research on the protection mechanism of fast control power in the field of nuclear fusion, and combination with the needs of nuclear fusion devices, a surge current suppression circuit, a voltage protection circuit, an overcurrent protection circuit, an overt-emperature protection circuit, an energy leakage protection circuit, and a crowbar were designed. Compared with the traditional protection method, the scheme has a wide protection range, strong reliability and high security. The experimental results show that the power protection system can ensure safe and reliable exit of the power supply in the event of a sudden failure, and effectively protect the superconducting magnets and power components of the superconducting Tokamak experimental device from damage, verifying the correctness and effectiveness of the designed scheme.

Evaluation of Aging's Effect on Temperature-Sensitive Electrical Parameters in SiC mosfets

The temperature-sensitive electrical parameters (TSEPs) have been used in silicon carbide (SiC) mosfets junction temperature measurement for over-temperature protection and condition monitoring. However, the device aging can affect the TSEPs and thus leads to false ${\boldsymbol{T}}_{\boldsymbol{j}}$ measurement. In this article, the aging's impacts on various TSEPs are comprehensively investigated. Specifically, utilizing the dc power cycling test, both the gate oxide instability and package degradation are considered. Then the commercial devices with different structures are aged, and their temperature-dependent static and switching characteristics are evaluated at different aging cycles. Both the positive gate bias-induced threshold voltage shift and package degradation are observed, and their impacts on each TSEP are evaluated independently. Based on the evaluation results at various operating conditions, the temperature measurement errors due to different aging mechanisms are well summarized for each TSEP. From the dc power cycling test result, the package degradation's impact on TSEPs is found to be more significant than the gate oxide instability. It is pointed out that the aging's effect on TSEPs is an important factor that needs to be considered for accurate ${\boldsymbol{T}}_{\boldsymbol{j}}$ measurement in SiC mosfets .

On-Chip THz Dynamic Manipulation Based on Tunable Spoof Surface Plasmon Polaritons

As one of the key components of terahertz (THz) application systems, the on-chip THz wave dynamic device has attracted much attention. In this letter, we propose an efficient way to dynamically manipulate the amplitude of an on-chip THz wave based on tunable spoof surface plasmon polaritons (SSPPs). A composite transmission line composed of metallic corrugated strips and vanadium dioxide (VO2) components is proposed to support the tunable SSPPs. By applying the insulator-metal transition characteristics of the VO2 components, it is found that the dispersion of SSPPs supported by this structure can be manipulated, which leads to the ability to tune the propagation of the transmitted THz wave. Both the experimental and simulated results show that the THz wave from 0.22 THz to 0.28 THz can be tuned and switched with a minimum insertion loss of −5.5 dB and a maximum switch ratio of 36 dB. The concept of tunable SSPPs presented here has important potential for the development of integrated THz dynamic devices with overtemperature protection circuits for integrated chips.

Analysis and Study in Testing of Infrared Therapy Equipment

This article summarizes the common problems in registration and supervision testing of infrared therapy equipment, combines YY 0306-2008 Particular requirements for the safety of heat radiation therapy equipment, GB 9706.1-2007 Medical electrical equipment-Part 1:General requirements for safety, Registration technical review guidelines for infrared treatment equipment, etc. This paper analyzes and discusses the following aspects, including classification and applicable standards, performance indicators and overtemperature protection. Some suggestions and solutions are given to provide some guidance for medical equipment manufacturers in design, research and development and registration, in order to avoid the problem effectively and improve the passing rate of testing.

Overtemperature protection systems for spallation target in China initiative accelerator driven sub-critical system

In an accelerator driven sub-critical system (ADS), a spallation target is irradiated by high-power proton beam to drive a sub-critical reactor. To continuously produce very intense neutrons, it is very important to prevent the unsafe operation of the target. This paper reports an over-temperature protection system for the spallation target in China initiative ADS system, where tungsten granules in the target container are used as both coolant and target materials. In order to protect the target from abnormal irradiation by the accelerator's beam when the granules are blocked or when the beam deviates from the target center, 12 sets of thermocouples are mounted inside the target container to monitor the target temperature. To evaluate the protection functions of these thermocouples, the heat transfer model of particles has been employed to investigate the spatio-temporal variations of the target temperatures when tungsten granules stay static in the target. The simulation results indicate that the temperatures of the thermocouples increase with the irradiation time and the granular blockage can be detected by analyzing the temperatures of these thermocouples. On the other hand, when the beam center deviates from the target center, the azimuthal distribution of the target temperature becomes non-uniform, and the temperature of the thermocouple close to the beam center increases faster. Finally, in the monitoring system for the over-temperature protection, 12 thermocouples divided into 3 groups which are fixed within the target in the upper, central and lower parts of the target, and 4 thermocouples in each group are located in four directions of east, south, west, and north. If two or more channels of four directions in one group exceed the set point, the protective function of granular blockage will be initiated; if two or more channels in one direction are greater than the set point, the protective function of beam deviation will be triggered.