Thermo-sensitive Electrical Parameter Research Articles

Junction temperature monitoring of silicon carbide MOSFET based on turn‐off voltage spike

AbstractBecause of the advantages of high switching speed, silicon carbide (SiC) devices are widely used in high‐power power electronic equipment. Real‐time monitoring of junction temperature is very important for the safe operation of equipment. There have been many studies on traditional junction temperature monitoring methods based on Si IGBT, but the dynamic characteristics of SiC MOSFETs are changed due to their different physical structure and parasitic parameters, which make the traditional methods no longer applicable. In this paper, the junction temperature can be extracted from the switching process of SiC MOSFET by using the turn‐off voltage spike as the index of thermosensitive electrical parameter (TSEP). In addition, the effect of working voltage, current, and different materials on turn‐off voltage spike is also studied. The simulation platform of Ansys/Simplorer and the experimental test platforms are built, and the theory of junction temperature detection based on turn‐off voltage spike is verified. The simulation and experimental results show that turn‐off voltage spike is a feasible TSEP, which can be used to extract junction temperature of SiC MOSFET with good linearity and instantaneity.

Thermo-sensitive electrical parameters of high-power IGBTs based on gate-emitter voltage measurement during switching delay intervals

High-power insulated gate bipolar transistors (IGBTs) are widely used for wind power conversion and electric traction. Accurate estimation of IGBT junction temperature and active thermal control improve the reliability of power converters in such applications. Among the various available methods for junction temperature estimation, thermo-sensitive electrical parameter (TSEP) based estimation is simple, fast and amenable to real-time implementation. Evaluation of many TSEPs (e.g. forward voltage, threshold voltage, peak dv/dt, peak di/dt etc.) require measurement of multiple electrical quantities in the power circuit and/or in the gate-drive circuit. The measurement systems need to have high precision and/or high bandwidth as well. Moreover, the quantities in the power circuit require isolated measurement systems. This paper explores possible new TSEPs, that could be obtained through a single measurement of low-voltage quantity, namely, the gate-emitter voltage. Since the gate-emitter voltage varies primarily during turn-on and turn-off delay intervals, these switching intervals and their parameters are studied over a wide range of operating conditions. Since many practical converters are expected to operate at an ambient temperature as low as −35 °C, the experimental study is carried out over a wide temperature range from −35 °C to 125 °C. Further, to ensure wider applicability of the findings of the study, four IGBTs of different makes are considered for the experimental investigations. The experimental results bring out four different parameters pertaining to turn-on delay and another four parameters pertaining to turn-off delay, which are potential TSEPs. Of these eight TSEPs, five of them can be evaluated based on measurement of gate-emitter voltage only, and four of these have not been reported in the literature previously. In addition, the experimental data are useful for development of temperature-sensitive device models for simulation, performance assessment and design of gate-drive circuit for different temperatures, and for temperature-sensitive compensation of inverter dead-time effect.

Research on IGBT junction temperature model based on united-parameters

The insulated gate bipolar transistor (IGBT) is the most expensive central component in the converter interior, but it is also one of the most vulnerable to failure. The failure of power electronic system is mainly due to temperature change. Therefore, the accurate extraction of IGBT module junction temperature is the basis of life prediction and reliability evaluation of high-power power conversion equipment. There is a great advantage in the non-invasive process of obtaining junction temperature through the dynamic temperature sensitive electrical parameter method; However, the measurement results are easily interfered with by a single dynamic temperature sensitive electrical parameter method. In this paper, a high-precision IGBT online junction temperature model based on united-parameters is proposed. The single dynamic thermosensitive electrical parameter only considers the change of a certain capacitance or inductance, which leads to the inaccurate measurement. A large number of effective temperature sensitive electrical parameters can be added to the model in order to reduce other disturbances and improve the accuracy and reliability of junction temperature prediction. Firstly, the limitations of each temperature sensitive electrical parameter were determined by comparing the existing temperature sensitive parameter method. Secondly, the appropriate united-parameters can be determined by theoretical analysis and practical verification. Finally, a junction temperature extraction model based on united-parameters was established by multiple linear regression method. Compared with the single dynamic TSEP-junction temperature, the proposed method has advantages in on-line temperature extraction and high precision monitoring.

Estimating Junction Temperature of SiC MOSFET Using Its Drain Current During Turn-On Transient

Silicon carbide metal–oxide–semiconductor field-effect transistor (SiC MOSFET) has become a promising device due to its excellent material properties. Junction temperature is an important parameter and a significant health index. In this article, drain current during turn-on transient is taken as the thermo-sensitive electrical parameter (TSEP) to monitor the junction temperature of SiC MOSFET. Based on the physical properties of wide bandgap semiconductor materials, the switching behaviors of SiC MOSFET and the variation of drain current with temperature were studied. The influence of temperature dependence of threshold voltage and carrier mobility on drain current is analyzed. It is proven that the drain current has a positive temperature coefficient during turn-on transient. Finally, the validity of the proposed method is verified by the theoretical analysis and experiments.

Power MOSFET Intrinsic Diode as a Highly Linear Junction Temperature Sensor

The characteristics of a thermo-sensitive electrical parameter used to estimate the junction temperature of power MOSFETs are presented. In particular, the dependence on temperature of the voltage appearing across the forward-biased body-diode at fixed currents is carefully investigated experimentally in order to optimize linearity and sensitivity. Error, resolution and repeatability are also discussed. The intrinsic diodes have been characterized in a wide working temperature range, namely between 25 °C and 175 °C, and for 1000 fixed probe currents between 10 $\mu \text{A}$ and 10 mA. The results show that the temperature sensor has high sensitivity and high linearity. It is shown that the best trade-off between sensitivity and linearity can be obtained in a particular bias current range. Finally, the sensor long-term stability has been tested.

Online Junction Temperature Monitoring Using Intelligent Gate Drive for SiC Power Devices

Junction temperature is an important design/operation parameter, as well as, a significant indicator of device's health condition for power electronics converters. Compared to its silicon (Si) counterparts, it is more critical for silicon carbide (SiC) devices due to the reliability concern introduced by the immaturity of new material and packaging. This paper proposes a practical implementation using an intelligent gate drive for online junction temperature monitoring of SiC devices based on turn- off delay time as the thermo-sensitive electrical parameter. First, the sensitivity of turn- off delay time on the junction temperature for fast switching SiC devices is analyzed. A gate impedance regulation assist circuit is proposed to enhance the sensitivity by a factor of 60 and approach 736 ps/°C tested in the case study with little penalty on the power conversion performance. Next, an online monitoring unit based on gate assist circuits is developed to monitor the turn- off delay time in real time with the resolution less than 104 ps. As a result, the micro-controller is capable of “reading” junction temperature during the converter operation. Finally, a SiC-based half-bridge inverter is constructed with an intelligent gate drive consisting of the gate impedance regulation circuit and online turn- off delay time monitoring unit. Experimental results demonstrate the feasibility and accuracy of the proposed approach.

IGBT Junction Temperature Measurements: Inclusive of Dynamic Thermal Parameters

Insulated gate bipolar transistors (IGBTs) are widely used in new energy fields, such as wind power converters and electric vehicles. The junction temperature characteristics and junction temperature measurements greatly influence the reliability of the IGBT. During switching, the electrical parameters of the IGBT undergo considerable change. The thermo sensitive electrical parameter (TSEP) method has been commonly used to extract junction temperature. The TSEP method has the inherent advantages of being able to take measurements quickly and accurately, in a non-intrusive manner. The junction temperature estimate under the on-state condition cannot reflect the reliability of the IGBT during the dynamic switching process. The solution to this dilemma is to measure the junction temperature using the dynamic TSEP method during the IGBT turn-off process. The junction temperature is measured by the reverse voltage peak between the auxiliary emitter and power emitter, which forms during the IGBT turn-off process. The feasibility of the proposed method has been experimentally verified.

Enabling Junction Temperature Estimation via Collector-Side Thermo-Sensitive Electrical Parameters Through Emitter Stray Inductance in High-Power IGBT Modules

This paper proposes the adoption of the inherent emitter stray inductance $L_{{\rm{eE}}}$ in high-power insulated gate bipolar transistor modules as a new dynamic thermo-sensitive electrical parameter (d-TSEP). Furthermore, a family of 14 derived dynamic TSEP candidates has been extracted and classified in voltage-based, time-based and charge-based TSEPs. Accordingly, the perspectives and the implementation challenges of the proposed method are discussed and summarized. Finally, high-power test platforms are designed and adopted to experimentally verify the theoretical analysis.

Analytical and Experimental Investigation on A Dynamic Thermo-Sensitive Electrical Parameter With Maximum $dI_{C}/dt$ During Turn-off for High Power Trench Gate/Field-Stop IGBT Modules

In this paper, a dynamic thermo-sensitive electrical parameter (DTSEP) for extracting the junction temperature of the trench gate/field-stop insulated gate bipolar transistor (IGBT) modules by using the maximum collector current falling rate is proposed. First, a theoretical model of the transient collector current during turn- off process is developed in terms of the behavior characteristics of the inside storage carriers. Then, the inherent linear relationship between the maximum collector current falling rate $dI_{C}/dt$ and junction temperature $T_{j}$ is demonstrated and investigated. Fortunately, benefitting from the presence of the intrinsic parasitic inductance $L_{\rm eE}$ between the Kelvin and power emitters of IGBT modules, the maximum $dI_{C}/dt$ can be easily measured to validate the theoretical analysis. Consequently, the maximum $dI_{C}/dt$ during turn- off process is a promising DTSEP for IGBT module junction temperature estimation. Moreover, the physical device parameters that affect the temperature sensitivity of the maximum $dI_{C}/dt$ are also discussed with the derived transient collector current falling model.

Online High-Power p-i-n Diode Junction Temperature Extraction With Reverse Recovery Fall Storage Charge

This paper proposes a method to extract the junction temperature of high-voltage and high-power p-i-n diodes. It is investigated that the swept-out charge during reverse recovery current fall time is affected by junction temperature variation, which makes the swept-out charge a possible thermo-sensitive electrical parameter (TSEP). Thanks to the specific package of high-power IGBT modules with p-i-n diodes, the swept-out charge of a p-i-n diode can be measured by the induced voltage v eE on the parasitic inductor L eE between Kelvin and power emitter terminals. In typical inductive half-bridge circuit, the comprehensive analysis of commutation between the upper p-i-n diode and lower enabled IGBT discloses the monotonic relationship among the reverse recovery charge, reverse current fall time, and junction temperature. A double pulse chopper circuit is used to validate the theoretical analysis. The experimental results show that the dependence between diode junction temperature and charge during the reverse recovery current fall time is approximately linear. A three-dimensional lookup table is calibrated and can be used to estimate the p-i-n diode junction operating temperature. Finally, an experimental comparison of four TSEPs for p-i-n diode is presented to verify the feasibility of the implementation of proposed TSEP.

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 (I C ), where the turn-off delay time (t doff ) and maximum decrease rate of I C (max dI C /dt) are adopted and combined. The two TSEPs both have linear relationships with junction temperature and I C . When they are combined mathematically, the influence of I 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 Real-Time Thermal Model for Monitoring of Power Semiconductor Devices

A resistance-capacitance (RC) thermal network with temperature-dependent thermal conductivities and heat capacitances is used to calculate the junction temperature of insulated-gate bipolar-transistor modules using a device model realized in Simulink. The collector current I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</sub> , collector-emitter voltage V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CE</sub> , and the case temperature T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</sub> measured during the cycling are used as input parameters of the proposed model. The proposed model is easier to implement compared with the thermosensitive electrical parameter (TSEP) method, and it is compared with an R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</sub> network with constant thermal conductivity and heat capacitance model and experimentally verified by using a TSEP method. The results of the proposed model show an improvement of the accuracy for determining the junction temperature compared with the model with constant thermal conductivity and heat capacitance.

Online High-Power P-i-N Diode Chip Temperature Extraction and Prediction Method With Maximum Recovery Current &lt;italic&gt;di&lt;/italic&gt;/&lt;italic&gt;dt&lt;/italic&gt;

P-i-N diode chip temperature is a significant indicator when evaluating the reliability of high-power converters. The feasibility of state-of-the-art thermosensitive electrical parameter (TSEP) extraction strategies for a high-power module is investigated and the limitations of using forward voltage drop for high-power P-i-N diode TSEP are explored. In the widely employed half-bridge topology, by detailed analysis of the upper antiparallel diode reverse recovery process due to lower nonideal insulated-gate bipolar transistor switching behavior, the inherent monotonic relationship between the maximum recovery current rate di d /dt and chip temperature is disclosed. The maximum di d /dt during the recovery period is chosen as the better TSEP, which can accurately reflect P-i-N diode chip temperature variation. Fortunately, by monitoring the negative peak voltage on the parasitic inductor between the Kelvin and power emitters under different temperatures, the maximum recovery rate di d /dt can be readily determined. Consequently, additional passive components are not required for P-i-N diode chip temperature extraction, which is practical and cost-effective for high-power applications. Finally, a dynamic switching characteristics test platform based on a half-bridge topology is designed and adopted to experimentally verify the theoretical analysis. The experimental results show that the dependence between P-i-N diode chip temperature and the maximum recovery di d /dt is approximately linear. This leads to a 3-D lookup table that can be used to estimate online P-i-N diode chip temperature.

A high temperature silicon carbide mosfet power module with integrated silicon-on-insulator-based gate drive

This paper presents a board-level integrated silicon carbide (SiC) mosfet power module for high temperature and high power density application. Specifically, a silicon-on-insulator (SOI)-based gate driver capable of operating at 200 °C ambient temperature is designed and fabricated. The sourcing and sinking current capability of the gate driver are tested under various ambient temperatures. Also, a 1200 V/100 A SiC mosfet phase-leg power module is developed utilizing high temperature packaging technologies. The static characteristics, switching performance, and short-circuit behavior of the fabricated power module are fully evaluated at different temperatures. Moreover, a buck converter prototype composed of the SOI gate driver and SiC power module is built for high temperature continuous operation. The converter is operated at different switching frequencies up to 100 kHz, with its junction temperature monitored by a thermosensitive electrical parameter and compared with thermal simulation results. The experimental results from the continuous operation demonstrate the high temperature capability of the power module at a junction temperature greater than 225 °C.

Junction Temperature Extraction Approach with Turn-off Delay Time for High-voltage High-Power IGBT Modules

Thermo-sensitive electrical parameter (TSEP) approaches are widely employed in the junction temperature extraction and prediction of power semiconductor devices. In this paper, the turn-off delay time is explored as an indicator of a TSEP to extract the junction temperature from high-power insulated gate bipolar transistor (IGBT) modules. The parasitic inductor L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eE</sub> between the Kelvin and power emitter terminals of an IGBT module is utilized to extract the turn-off delay time. Furthermore, the monotonic dependence between the junction temperature and turn-off delay time is investigated. The beginning and end point of the turn-off delay time can be determined by monitoring the induced voltage v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eE</sub> across the inductor L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eE</sub> . A dynamic switching characteristic test platform for high-power IGBT modules is used to experimentally verify the theoretical analysis. The experimental results show that the dependency between IGBT junction temperature and turn-off delay time is near linear. It is established that the turn-off delay time is a viable TSEP with good linearity, fixed sensitivity, and offers nondestruction on-line IGBT junction temperature extraction.