Online Monitoring Method for Junction Temperature of SiC MOSFETs based on Temperature Sensitive Electrical Parameter

Compared to Si devices,the junction temperature of SiC devices is more critical due to the reliability concern introduced by immature packaging technology applied to new material.This paper proposes a practical SiC MOSFET junction temperature monitoring method based on the on-state voltage$\\boldsymbol{V}_{\\mathbf{ds}(\\mathbf{on})}$measurement.In Section II of the paper,the temperature sensitivity of the on-state voltage$\\boldsymbol{V}_{\\mathbf{ds}(\\mathbf{on})}$is characterized.The hardware of the measurement system is set up in Section III,which consists of an On-state Voltage Measurement Circuit(OVMC),the sampling and isolation circuit.Next,a calibration method based on the self-heating of the SiC MOSFET chip is presented in Section IV.In the final Section,the junction temperature is monitored synchronously according to the calibration results.The proposed method is applied to a Buck converter and verified by both an Infrared Radiation(IR)camera and a Finite Element Analysis(FEA)tool.

Effect of junction temperature on the large-signal properties of a 94 GHz silicon based double-drift region impact avalanche transit time device

The authors have developed a large-signal simulation technique extending an in-house small-signal simulation code for analyzing a 94 GHz double-drift region impact avalanche transit time device based on silicon with a non-sinusoidal voltage excitation and studied the effect of junction temperature between 300 and 550 K on the large-signal characteristics of the device for both continuous wave （CW） and pulsed modes of operation. Results show that the large-signal RF power output of the device in both CW and pulsed modes increases with the increase of voltage modulation factor up to 60%, but decreases sharply with further increase of voltage modulation factor for a particular junction temperature; while the same parameter increases with the increase of junction temperature for a particular voltage modulation factor. Heat sinks made of copper and type-IIA diamond are designed to carry out the steady-state and transient thermal analysis of the device operating in CW and pulsed modes respectively. Authors have adopted Olson＇s method to carry out the transient analysis of the device, which clearly establishes the superiority of type-IIA diamond over copper as the heat sink material of the device from the standpoint of the undesirable effect of frequency chirping due to thermal transients in the pulsed mode.

Monitoring of SiC MOSFET Junction Temperature with On-state Voltage at High Currents

A junction temperature monitoring method has been presented based on the on-state voltage at high currents.With a simplified physical model,this method mapped the relationship between junction temperature and on-state voltage.The tough calibration and signal sensing issues are solved.Verified by body-diode voltage detecting method,the presented method shows a good performance and high accuracy,in the meantime,it would not change the modulation strategy and topology of the converter.

Online Junction Temperature Measurement of Double-sided Cooling IGBT Power Module through On-state Voltage with High Current

The aim of this study is to achieve online monitoring of the junction temperature of double-sided-cooling insulated gate bipolar transistor(IGBT)power modules by using the on-state voltage under a high current to maximize the utilization of IGBT power chips.Online junction temperature measurement plays an important role in improving the reliability of the inverter with IGBT,increasing the power density of the motor controller of electric vehicles,and reducing the cost of electric vehicles.

A novel electrical measurement method of peak junction temperature based on the excessive thermotaxis effect of low current

It has been a scientific and technological problem in the field of microelectronics for several decades that the electrical method is used to measure the peak junction temperature of power transistors. Based on the excessive thermotaxis effect of low current, a novel electrical measurement method of the peak junction temperature is presented in this paper. The method is called the thermal spectrum analysis method of transistors, simply designated TSA （thermal spectrum analysis method）. Unlike the common method which uses a single measuring current, TSA uses multi-step currents to measure temperature-sensitive parameters. Based on the excessive thermotaxis effect of low current and the sub-transistor parallel model, the peak junction temperature and non-uniform property of junction temperature distribution are analyzed successfully.

Junction temperature measurement of alternating current light-emitting-diode by threshold voltage method

Junction temperature of alternating current light-emitting-diode （AC-LED） has a significant effect on its stable light output and lifetime. The threshold voltage measurement is employed to characterize the junction temperature of AC-LED, due to its excellent merits in high efficiency and accuracy. The threshold voltage is measured when the driving current of an AC-LED rises to a reference on-set value from the zero-crossing node. Based on multiple measurements of threshold voltage at different temperatures, a linear relationship was uncovered between the threshold voltage and the junction temperature of AC- LED with the correlating factor of temperature sensitive parameter （TSP）. Thereby, we can calculate the junction temperature with the TSP and threshold voltage once the AC-LED stays at thermal equilibrium state. The accuracy of the proposed junction temperature measurement technique was found to be ＋3.2℃ for the reference current of 1 mA. It is concluded that the method of threshold voltage is accurate and simple to implement, making it highly suitable for measuring the junction temperature of AC-LED in industry.

Elimination of Collector Current Impact in TSEP-based Junction Temperature Extraction Method for High-Power IGBT Modules

Insulated gate bipolar transistor(IGBT)modules are widely employed in high-power conversion systems.Their junction temperature ranks as one of the most important factors in the reliability of power semiconductor devices.Thermo-sensitive electrical parameter(TSEP)is regarded as the promising solution to extract the junction temperature due to its non-invasion measurement,fast response and high accuracy.However,accurate collector current measurement is required if only the individual TSEP is adopted,which increases the complexity and cost.In this paper,the combined TSEP method is proposed to eliminate the influence of collector current(/c),where the turn-off delay time(tdoff)and maximum decrease rate of/c(max d/c/dt)are adopted and combined.The two TSEPs both have linear relationships withjunction temperature and/c.When they are combined mathematically,the influence of/c is eliminated.Experiments have been implemented to validate the effectiveness of the proposed approach.The comparison between combined TSEP and two individual TSEP methods are illustrated and analyzed.

A study on temperature monitoring method for inverter IGBT based on memory recurrent neural network

The power module of the Insulated Gate Bipolar Transistor(IGBT)is the core component of the traction transmission system of high-speed trains.The module's junction temperature is a critical factor in determining device reliability.Existing temperature monitoring methods based on the electro-thermal coupling model have limitations,such as ignoring device interactions and high computational complexity.To address these issues,an analysis of the parameters influencing IGBT failure is conducted,and a temperature monitoring method based on the Macro-Micro Attention Long Short-Term Memory(MMALSTM)recursive neural network is proposed,which takes the forward voltage drop and collector current as features.Compared with the traditional electricalthermal coupling model method,it requires fewer monitoring parameters and eliminates the complex loss calculation and equivalent thermal resistance network establishment process.The simulation model of a highspeed train traction system has been established to explore the accuracy and efficiency of MMALSTM-based prediction methods for IGBT power module junction temperature.The simulation outcomes,which deviate only 3.2% from the theoretical calculation results of the electric-thermal coupling model,confirm the reliability of this approach for predicting the temperature of IGBT power modules.

IGBT Temperature Field Monitoring Based on Reduced-order Model

With the rapid development of the world economy,IGBT has been widely used in motor drive and electric energy conversion.In order to timely detect the fatigue damage of IGBT,it is necessary to monitor the junction temperature of IGBT.In order to realize the fast calculation of IGBT junction temperature,a finite element method of IGBT temperature field reduction is proposed in this paper.Firstly,the finite element calculation process of IGBT temperature field is introduced and the linear equations of finite element calculation of temperature field are derived.Temperature field data of different working conditions are obtained by finite element simulation to form the sample space.Then the covariance matrix of the sample space is constructed,whose proper orthogonal decomposition and modal extraction are carried out.Reasonable basis vector space is selected to complete the low dimensional expression of temperature vector inside and outside the sample space.Finally,the reduced-order model of temperature field finite element is obtained and solved.The results of the reduced order model are compared with those of the finite element method,and the performance of the reduced-order model is evaluated from two aspects of accuracy and rapidity.

Reliability evaluation of IGBT power module on electric vehicle using big data

There are challenges to the reliability evaluation for insulated gate bipolar transistors(IGBT)on electric vehicles,such as junction temperature measurement,computational and storage resources.In this paper,a junction temperature estimation approach based on neural network without additional cost is proposed and the lifetime calculation for IGBT using electric vehicle big data is performed.The direct current(DC)voltage,operation current,switching frequency,negative thermal coefficient thermistor(NTC)temperature and IGBT lifetime are inputs.And the junction temperature(T_(j))is output.With the rain flow counting method,the classified irregular temperatures are brought into the life model for the failure cycles.The fatigue accumulation method is then used to calculate the IGBT lifetime.To solve the limited computational and storage resources of electric vehicle controllers,the operation of IGBT lifetime calculation is running on a big data platform.The lifetime is then transmitted wirelessly to electric vehicles as input for neural network.Thus the junction temperature of IGBT under long-term operating conditions can be accurately estimated.A test platform of the motor controller combined with the vehicle big data server is built for the IGBT accelerated aging test.Subsequently,the IGBT lifetime predictions are derived from the junction temperature estimation by the neural network method and the thermal network method.The experiment shows that the lifetime prediction based on a neural network with big data demonstrates a higher accuracy than that of the thermal network,which improves the reliability evaluation of system.

Thermal Analysis of High Power LED on Heat Sink

Thermal management of LED junction temperature is one of the fundamental technologies for LED lamp to ensure basic specifications in many aspects. Analysed is the high power LED's distribution on heat sink. Using mathematical statistical methods, a formula is conlcuded to calculate the size of heat sink under LED safe working temperature, which provides a method to researchers and LED lamp manufacturers.

Study on High-power LED Heat Dissipation Based on Printed Circuit Board

In order to study the role of printed circuit board(PCB)in high-power LED heat dissipation,a simple model of high-power LED lamp was designed.According to this lamp model,some thermal performances such as thermal resistances of four types of PCB and the changes of LED junction temperature were tested under three different working currents.The obtained results indicate that LED junction temperature can not be lowered significantly with the decreasing thermal resistance of PCB.However,PCB with low thermal resistance can be matched with smaller volume heat sink,so it is hopeful to reduce the size,weight and cost of LED lamp.

Lifetime estimation of IGBT module using square-wave loss discretization and power cycling test

The insulated gate bipolar transistor(IGBT)module is one of the most age-affected components in the switch power supply, and its reliability prediction is conducive to timely troubleshooting and reduction in safety risks and unnecessary costs. The pulsed current pattern of the accelerator power supply is different from other converter applications;therefore, this study proposed a lifetime estimation method for IGBT modules in pulsed power supplies for accelerator magnets. The proposed methodology was based on junction temperature calculations using square-wave loss discretization and thermal modeling.Comparison results showed that the junction temperature error between the simulation and IR measurements was less than 3%. An AC power cycling test under real pulsed power supply applications was performed via offline wearout monitoring of the tested power IGBT module. After combining the IGBT4 PC curve and fitting the test results,a simple corrected lifetime model was developed to quantitatively evaluate the lifetime of the IGBT module,which can be employed for the accelerator pulsed power supply in engineering. This method can be applied to other IGBT modules and pulsed power supplies.

Thermal Resistance Testing Technology Research of Integration High Power-LED

In this paper,high-power LED with many integrated chips is used as thermal resistance analysis research object, and we do thermal resistance testing technology research on it. We put forward the thermocouple point contact test method. According to the principle that LED forward voltage changes with temperature,LED heat sink to surface temperature distribution is studied directly in the test,and then we analyze the thermal resistance of high-power LED with many integrated chips when its secondary packaging is introduced. This method makes the measurement of thermal resistance of LED more rapid and convenient. It provides an effective assessment method for the analysis of high power LED device design and engineering application.

Thermal Design for 5 Watt Power LED

With the consideration of the thermal management and heat sink requirements,a cooling device is designed and the thermal resistance of this device is calculated with a single 5 W power LED.The thermal design of a single 5 W power LED is reasonable,effective and the result has been simulated.This design also instruct other power LEDs' thermal design.Provided is a reliable and effective method for the design of power LED illumination lamps and lanterns.

Investigation on Effect of Radial and Extended Fins in PCM Heat Sink for LED Cooling

This work focuses on the efficiency of the LED acting as the heat sink containing Phase Change Material(PCM). Three different heat sink configurations(H-1, H-2, and H-3) are used in this study. Input power and the number of fins are altered to find their effect on junction temperatures, luminous flux, and thermal resistance. The junction temperature of heat sink H-3 with PCM decreased by 3.1 % when compared with heat sink devoid of PCM at 10 W. The thermal resistance of the heat sink H-3 is reduced by 18.2 % when compared to its counterpart devoid of PCM at 10 W. The luminous flux of the PCM filled heat sink H-3 is found to increase by 12.15 % against the PCM not filled heat sink H-1 at 10 W. The H-3 heat sink with PCM showed superior performance because of the enhanced natural convection and conduction in bulk PCM with fins, and with added high latent heat capacity of PCM.

Junction-temperature estimation in AlGaInP light-emitting diodes using the luminescence spectra method

This study proposes a practical method to estimate the junction temperature of AlGaInP LEDs using the luminescence spectra method.The peak wavelength shift of LEDs is due to the energy band gap shrinking.The temperature dependence of the bandgap of AlGalnP LEDs is derived from those of the underlying binary compounds A1 P,GaP,and InP.Based on this,a theoretical model for the dependence of the peak wavelength on junction temperature is developed.Experimental results on the junction temperature of AlGalnP red light-emitting diodes are presented.Excellent agreement between the theoretical and experimental temperature dependence of the peak wavelength is found.

Improvements on high voltage capacity and high temperature performances of Si-based Schottky potential barrier diode

In order to improve the reverse voltage capacity and low junction temperature characteristics of the traditional silicon-based Schottky diode,a Schottky diode with high reverse voltage capacity and high junction temperature was fabricated using ion implantation,NiPt60 sputtering,silicide-forming and other major technologies on an N-type silicon epitaxial layer of 10.6-11.4μm and（2.2-2.4）×10^15 cm^-3 doping concentration.The measurement results show that the junction temperature of the Schottky diode fabricated can reach 175 °C,that is 50°C higher than that of the traditional one;the reverse voltage capacity VR can reach 112 V,that is 80 V higher than that of the traditional one;the leakage current is only 2μA and the forward conduction voltage drop is VF=0.71 V at forward current If =3 A.

A Detailed Thermal Resistance Network Analysis of FCBGA Package

Using thermal models to describe the heat dissipation process of FCBGA is a significant topic in the field of packaging.However,the thermal resistance model considering the structure of each part of the chip is still ambiguous and rare,but it is quite desirable in engineering.In this work,we propose a detailed thermal resistance network model,and describe it by using thermal conduction resistance and thermal spreading resistance.For a striking FCBGA case,we calculated the thermal resistance of each part of the structure according to the temperature field simulated by COMSOL.The thermal resistance network can be used to predict the temperatures in the chip under different conditions.For example,when the power changes by 40%,the relative error of junction temperature prediction is only 0.24%.The function of the detailed thermal resistance network in evaluating the optimization space and determining the optimization direction is clarified.This work illustrates a potential thermal resistance analysis method for electronic devices such as FCBGA.

Thermal simulation and analysis of flat surface flip-chip high power light-emitting diodes

Conventional GaN-based flip-chip light-emitting diodes （CFC-LEDs） use Au bumps to contact the LED chip and Si submount, however the contact area is constrained by the number of Au bumps, limiting the heat dissipation performance. This paper presents a flat surface high power GaN-based flip-chip light emitting diode （SFC-LED）, which can greatly improve the heat dissipation performance of the device. In order to understand the thermal performance of the SFC-LED thoroughly, a 3-D finite element model （FEM） is developed, and ANSYS is used to simulate the thermal performance. The temperature distributions of the SFC-LED and the CFC-LED are shown in this article, and the junction temperature simulation values of the SFC-LED and the CFC-LED are 112.80 ℃ and 122.97℃C, respectively. Simulation results prove that the junction temperature of the new structure is 10.17 ℃ lower than that of the conventional structure. Even if the CFC-LED has 24 Au bumps, the thermal resistance of the new structure is still far less than that of the conventional structure. The SFC-LED has a better thermal property.