Temperature Sensitive Electrical Parameters Research Articles

Steady-State Temperature-Sensitive Electrical Parameters’ Characteristics of GaN HEMT Power Devices

Gallium nitride high-electron-mobility transistor (GaN HEMT) power devices are favored in various scenarios due to their high-power density and efficiency. However, with the significant increase in the heat flux density, the junction temperature of GaN HEMT has become a crucial factor in device reliability. Since the junction temperature monitoring technology for GaN HEMT based on temperature-sensitive electrical parameters (TSEPs) is still in the exploratory stage, the TSEPs’ characteristics of GaN HEMT have not been definitively established. In this paper, for the common steady-state TSEPs of GaN HEMT, the variation rules of the saturation voltage with low current injection, threshold voltage, and body-like diode voltage drop with temperature are investigated. The influences on the three TSEPs’ characteristics are considered, and their stability is discussed. Through experimental comparison, it is found that the saturation voltage with low current injection retains favorable temperature-sensitive characteristics, which has potential application value in junction temperature measurement. However, the threshold voltage as a TSEP for certain GaN HEMT is not ideal in terms of linearity and stability.

IGBT Junction Temperature Extraction via Voltage Integral over Voltage Rise Period

In this paper, a temperature sensitive electrical parameter (TSEP) method for insulated gate bipolar transistor (IGBT) modules junction temperature estimation based on voltage integral over-voltage rise period (VIVRP) is proposed. Firstly, combined with the principles of thermodynamic physics, the movement characteristics of internal carriers and holes are discussed, and the waveform of voltage and current during the turn-off process is studied. The feasibility of using voltage integral overvoltage period instead of voltage rise loss in junction temperature measurement is discussed and proved. At the beginning of the turn-off process, the holes in the IGBT almost remain in spatial and temporal distribution (the collector current IC remains constant), which leads the VIVRP to a cheaper TSEP method for junction temperature detection, without the high-frequency current detection equipment. Finally, the junction temperature model based on VIVRP and the extraction circuit of VIVRP are proposed. In addition, it is compared with the junction temperature detection method based on the voltage rise time and voltage rise loss. The results show that the junction temperature detection method based on VIVRP proposed in this paper is detection with high precision and low cost.

Machine learning-based prediction of on-state voltage for real-time health monitoring of IGBT

Real-time temperature monitoring of power semiconductors is a powerful tool for the predictive maintenance and lifetime prediction of power converters, and is typically performed by measuring temperature sensitive electrical parameters (TSEP). In this work, we demonstrate a machine learning-based method to estimate the on-state voltage of a real converter prototype featuring variable load of electric vehicle (EV) and photovoltaic (PV) systems under different ambient temperatures induced in a climate chamber. The method provides for the first-time insights on the uncertainties and feature importance for the predictions, and is aimed to be industrial compatible by applying only methods that are well established in industry. The approach is further flexible to any converter system, independently of its specifications. We have used the Support Vector Machine, K-Nearest Neighbors, and Decision Tree algorithms to predict the on-state voltage as functions of the readily measured parameters of a converter. We show that for the PV case, the K-Nearest Neighbor method yields the lowest mean absolute error of about 0.75 % for prediction, while for EV, the K-Nearest Neighbor algorithm gives the lowest mean absolute error of 5 %.

AC Power Cycling Test Setup and Condition Monitoring Tools for SiC-Based Traction Inverters

AC power cycling tests allow the most realistic reliability assessment by applying close to real stress to the device or module under test to meet functional safety standards, which is highly critical for traction applications. This paper presents a comprehensive guideline and shares critical know-how to develop a 120 KVA AC power cycling test setup for high-power Silicon Carbide (SiC) modules. As of today, traction applications can not generate an early warning signal for drivers to replace critical components on time. For this purpose, the suitable precursors for all dominant failure mechanisms are discussed, and the corresponding condition monitoring tools are proposed to monitor the device aging on power converters. These condition monitoring tools are integrated into the built-in desaturation protection circuit of the electric vehicle (EV) gate driver for low-cost, practical implementation. The on-resistance of all twelve switches is monitored online as a temperature-sensitive electrical parameter (TSEP) to measure the junction temperature of the devices. To avoid heavy processing load in the microcontroller, the out-of-order equivalent time sampling technique is developed for data sampling, which leads to a measurement error of less than 1.5%. In addition, the design considerations regarding common mode noise and aging effect on DESAT protection are investigated, and experimental findings are presented.

Health Monitoring of Power Semiconductor Module Using Temperature Sensitive Electrical Parameter

Power semiconductor modules (PSMs) are critical components in power electronics applications such as motor drives, renewable energy systems, and electric vehicles. The reliable operation of these modules is crucial for the safe and efficient operation of these systems. One of the most common failure mechanisms in PSMs is due to overheating or repeated heating and cooling, which can result in thermal stress and component degradation. Therefore, monitoring the temperature of PSMs is essential for ensuring their health and preventing catastrophic failures. By monitoring temperature-sensitive electrical parameters (TSEPs), such as the on-state voltage drop, it is possible to detect changes in the temperature of the PSM in real-time. The change in voltage drop can be used as an early warning sign of a potential failure or degradation of the PSM. The advantage of this method is that it provides a non-invasive and real-time monitoring solution that can detect changes in the PSM's temperature distribution.

Investigation and Comparison of Temperature-Sensitive Electrical Parameters of SiC mosfet at Extremely High Temperatures

Due to the excellent silicon carbide (SiC) material characteristics, SiC MOSFETs can operate at extremely high temperatures and can be used in harsh environment applications. In this case, it is crucial to ensure the reliability of the power electronic systems. The temperature-sensitive electrical parameters (TSEPs) have been used for online junction temperature monitoring to monitor the health condition of the SiC MOSFET at low temperatures (<175℃). However, the performance of the TSEPs at extremely high temperatures is still unknown, and the influence of temperature on the TSEPs of SiC MOSFET at extremely high temperatures is unclear. In this article, the theoretical mechanisms of the impact of the extremely high temperature on TSEPs are investigated in detail. In particular, the different effects of high temperature on the turn-on delay time and turn-off delay time are discussed carefully. Based on the high-temperature characteristic test method proposed, the TSEPs of SiC MOSFET (including static and dynamic characteristics) are tested and analyzed comprehensively from room temperature to 375℃. And the sensitivity and linearity of the TSEPs in different temperature ranges are analyzed and compared. According to the results, threshold voltage and turn-off delay time are the two TSEPs with good sensitivity and linearity over a wide temperature range (from room temperature to 375℃). And the linearity of turn-off delay time is the best among all TSEPs over a wide temperature range.

A Novel Temperature Sensitive Electrical Parameter of IGBT Modules Without Involvement of Operating Parameters

The junction temperature estimation of the insulated gate bipolar transistor (IGBT) module is crucial for reliability assessment and health management of converters. However, most of the existing methods need to measure the collector-emitter voltage and collector current for the IGBT junction temperature estimation, which increases the cost and complexity of the monitoring and calibration process. In this article, a novel junction temperature monitoring method for IGBT modules without involving operating condition calibration based on the pre-overshoot of gate voltage is proposed. The gate pre-overshoot is influenced by the internal gate resistor, which has a linear relationship with the IGBT junction temperature. Besides, the gate pre-overshoot is only temperature dependent, while not affected by the collector-emitter voltage and collector current. Therefore, the gate pre-overshoot is a promising temperature-sensitive electrical parameter (TSEP). Because the collector-emitter voltage and collector current are not involved, the gate pre-overshoot-based method for junction temperature has the advantages of a simple signal monitoring structure, a simple calculation process, and a simple calibration process.

Power Cycling on Lateral GaN and β-Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; Transistors

The load cycling capability of novel power semiconductors is an important aspect when estimating their lifetime in field service. The Power Cycling Test (PCT) is the standard test to evaluate the lifetime of a semiconductor device under thermo-mechanical stress. PCTs are typically performed at temperature swings (ΔT) much higher than common operating conditions, to obtain results within a reasonable time. In this work, the PCT capability of gallium nitride (GaN) and gallium oxide (Ga2O3) lateral transistors is investigated. The GaN devices were tested in two groups with different ΔT. The temperature of the devices was monitored using two different temperature sensitive electrical parameters (TSEPs) and the accuracy of both methods was evaluated by comparing the results with the temperature, monitored by using an infrared (IR) camera. For Ga2O3 devices, no data on potential TSEP exists so far, thus, the typical TSEP for silicon (Si), silicon carbide (SiC) and GaN were investigated for their applicability to Ga2O3 devices. While a PCT was conducted on the devices, the temperature was also monitored using an IR camera. The results of the comparison of TSEP and IR camera data showed, that the accuracy of the TSEP for GaN matched either the temperature of the hottest spot on the chip (VDS method), or the average chip temperature (VGS method). For the Ga2O3 devices no suitable TSEP could be obtained and only the IR camera was used for the temperature measurement. It revealed a very uneven temperature and thus, current distribution on the chip. Furthermore, both GaN and Ga2O3 devices exhibit an outstanding power cycling capability with no failure after completing several millions of cycles. Considering the difference in Young’s Modulus of Si, GaN and Ga2O3, the PCT performance of GaN on silicon devices and Ga2O3 devices should be inferior to silicon devices. Thus, both device types, the GaN transistors and the Ga2O3 transistors, showed a PCT capability much higher than expected.

A Simple Method to Extract the Thermal Resistance of GaN HEMTs From De-Trapping Characteristics

This paper proposes a new method for extracting the thermal resistance of GaN-based HEMTs using pulse recovery data. After the device temperature and trapping state are established from different quiescent power dissipations for several base-plate temperatures, the recovery profile of the drain current is measured. The recovery time is then used as a temperature-sensitive electrical parameter to extract the thermal resistance of the device. The proposed method has been applied to a Schottky-gate HEMT on SiC, for which a thermal resistance of 15.7 °C-mm/W was extracted, a value in good agreement with others reported for similar devices. Comparison with the one obtained from a step response is also done. Finally, the uncertainties of the proposed method related to the pulse width, temperature, percentage of the drain current recovery time, and averaging procedure are discussed.

IGBT Junction Temperature Estimation Using a Dynamic TSEP Independent of Wire Bonding Faults

Despite that many temperature-sensitive electrical parameters (TSEPs) have been discovered for the online estimation of the junction temperature of IGBT devices, their wide adoption in the field is yet to come. This is because they are most susceptible to both the aging status and operating points of IGBTs, which can result in inaccurate results if not attended. In this study, a novel dynamic TSEP, the gate voltage undershoot <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GE(np)</sub> of the complementary IGBT switch, is proposed. It is based on the crosstalk effect and measured during the turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> switching transition of the controlled IGBT switch for its temperature estimation. Its monotonic temperature dependence has been identified with implications for the changing load current and bus voltage, which are experimentally verified using a 1200 V/450 A IGBT module. The theoretical analysis and experimental results also show that <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GE(np)</sub> is independent of bond wire failures while providing comparatively high relative sensitivity. The MMC power equivalent experimental results are given to verify the feasibility of the proposed method in commercial engineering applications. Finally, the multivariate linear regression method is used to improve the ability to estimate the IGBT's temperature by accounting for the operating point.

Comparative Study of the Parameter Acquisition Methods for the Cauer Thermal Network Model of an IGBT Module

Under the operating conditions of high power and high switching frequency, an insulated gate bipolar transistor (IGBT) chip can produce relatively large power loss, causing the junction temperature to rise rapidly; consequently, the reliability of the IGBT module can be seriously affected. Therefore, it is necessary to accurately predict the junction temperature of the IGBT chip. The resistance capacitance (RC) thermal network model is a commonly used method for IGBT junction temperature prediction. In this paper, the model parameters are obtained by two methods to establish the Cauer thermal network models of the IGBT module. The first method is to experimentally obtain the transient thermal impedance curve of the IGBT module and the structure function and then extract the individual thermal parameters of the Cauer thermal network model; the second method is to obtain the thermal parameters of the thermal network model directly by using theoretical formulas that consider the influence of the heat spreading angle. The predicted junction temperatures of the Cauer thermal network models established by the two methods are compared with the junction temperatures obtained from infrared (IR) measurements during the power cycling test, the junction temperatures measured by the temperature-sensitive electrical parameter (TSEP) method, and the junction temperatures calculated by finite element (FE) analysis. Additionally, the Cauer thermal network models established by the two methods are compared and verified. The results indicate that the Cauer thermal network model established based on theoretical formulas can accurately predict the maximum junction temperature of the IGBT chip, and the calculated temperature for each layer, from the IGBT chip layer to the ceramic layer, also accords well with the FE results. The Cauer thermal network model established based on the experimental test and the structure function can accurately predict the average junction temperature of the IGBT chip.

A Novel IGBT Junction Temperature Detection Based on High-Frequency Model of Inductor Element

Accurate online junction temperature detection of high-power insulated gate bipolar transistor (IGBT) modules is necessary for the health management system of key equipment. The voltage rise time ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$t_{\mathrm {rv}}$ </tex-math></inline-formula> ) is a good temperature sensitive electrical parameter (TSEP), which is of great significance for its accurate online extraction. In this article, a novel IGBT junction temperature detection based on the high-frequency (HF) model of inductor element is proposed. First, the equivalent model of the inductor element in the application circuit at HF is demonstrated. Second, based on the HF model of the inductor element, it is proposed and verified that <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$t_{\mathrm {rv}}$ </tex-math></inline-formula> in the IGBT turn-off process is consistent with the HF current pulse signal on the inductor element at HF, that is, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$t_{\mathrm {rv}}$ </tex-math></inline-formula> can be indirectly obtained by extracting the HF current pulse signal. Finally, the feasibility for voltage rise time extraction and junction temperature detection through HF isolation coil is verified by experiments and simulations. The research work in this article is helpful to the online junction temperature detection and has certain theoretical significance and practical engineering value.

Junction Temperature Measurement Based on the Internal Gate Resistance for a Wide Range of Power Semiconductors

This paper presents research results on the junction temperature measurement via the internal gate resistance in converter operation for IGBTs and its applicability to other types of active power semiconductors. A junction temperature monitor has been developed to determine the value of the temperature-dependent internal gate resistance by using a sinusoidal voltage superimposed on the gate voltage at the resonance frequency. The device enables a simple and robust junction temperature measurement in inverter operation, which is in excellent agreement with an infrared reference measurement. The method's applicability to semiconductors other than Si-IGBTs, such as SiC-MOSFETs, JFETs, and GaN devices, is verified by gate impedance measurements using a network analyzer. The gate impedance's quality factor is decisive. Other temperature-sensitive electrical parameters (TSEPs) related to the switching behavior depend on the internal gate resistance. Therefore, the findings presented are relevant for many junction temperature measurement methods.

An On-Line Calibration Method for TSEP-Based Junction Temperature Estimation

Temperature sensitive electrical parameters (TSEP) provide an indirect and noninvasive method for on-line junction temperature estimation of power semiconductor devices. It is known that the fundamental of TSEP-based methods is to calibrate the relationship between TSEP and junction temperature in advance. However, the calibration methods in the literature need to open the module, require pretesting, or record the operating data of a converter in the entire power rating range, which are inconvenient in field applications. This article proposes an on-line and noninvasive calibration method by measuring the data at three operating states that are already existed in the regular converter operation. It is achieved by measuring the accessible heatsink/case temperature and TSEP during converter regular operation. The concept, implementation, and error analysis of the proposed method are presented in this article. Experimental verification is given to prove the effectiveness, accuracy, and convenience of the proposed method.

Evaluating On-State Voltage and Junction Temperature Monitoring Concepts for Wide-Bandgap Semiconductor Devices

Monitoring or estimating the junction temperature of power semiconductor devices is a requirement for degradation monitoring and predictive maintenance of power-electronic converters and usually achieved by online measurement of a temperature-sensitive electrical parameter (TSEP). Many TSEPs rely on switching transients and, thus, depend on the design of a switching cell, driving significant calibration efforts. Instead, utilizing the on-state voltage of a power semiconductor device as TSEP is attractive, as it only depends on the load current and the output characteristic of the device. This independence of the switching cell design enables on-state voltage monitoring circuits to be seamlessly integrated into products that are already mass produced. However, an effective on-state voltage monitoring circuit has to measure small on-state voltages accurately and fast while withstanding high off-state voltages. This article experimentally evaluates three candidate circuits that take on this challenge: a circuit derived from a Wheatstone bridge, a dynamically compensated voltage divider, and a circuit using an auxiliary MOSFET. PCBs are designed, featuring all three circuit concepts, and experiments are carried out to compare the candidate circuits in terms of dynamic performance and resolution. Finally, the potential for integration into commercial products is outlined, illustrated, and discussed.

An Online Junction Temperature Monitoring Correction Method for SiC MOSFETs at Different Parasitic Parameters

Due to the remarkable performance of silicon carbide (SiC) metal–oxide–semiconductor field-effect transistor (MOSFET) on high temperature, it is promising in future applications in various applications. The accurate online junction temperature based on dynamic temperature-sensitive electrical parameters (TSEPs) is significant for the protection and condition monitoring, which can prolong or monitor the lifetime of SiC MOSFET devices. In this article, four different dynamic TSEPs, including turn-on delay time, turn-off delay time, and maximum current turn-on and turn-off switching rates, are theoretically analyzed taking the parasitic parameters into consideration. The experimental analysis of the influence of parasitic parameters ’ dynamic TSEPs is carried on using a buck converter test setup. Based on the theoretical and experimental analyses, a junction temperature correction method is proposed for SiC MOSFET. The online junction temperature monitoring experiments are used to verify the accuracy and effectiveness of the proposed method. The results show that the proposed correction method can largely eliminate the junction temperature monitoring error at different parasitic parameters. The maximum measurement error is reduced from 147 °C to 4.7 °C after correction.

Improved Measurement Accuracy for Junction-to-Case Thermal Resistance of GaN HEMT Packages by Gate-to-Gate Electrical Resistance and Stacking Thermal Interface Materials

Accurate measurements of the junction-to-case thermal resistances of power devices or module packages are necessary for validating the thermal design of the package as well as of the entire converter system. Although accurate measurements can be obtained for Si and SiC packages by the JESD51-14 standard, no standard has been established for gallium nitride (GaN) packages. A main reason for this shortcoming is the lack of accurate techniques for measuring the device's junction temperature. In this letter, a custom package of a (650 V, 150 A) eGaN high-electron mobility transistor with two gate pads was fabricated, and then its junction-to-case thermal resistance was measured by combining two techniques to improve the accuracy: using the device's gate-to-gate electrical resistance as the temperature-sensitive electrical parameter; and measuring the thermal resistance as a function of added layers of thermal interface materials. The first gives a sensitivity of 4.7 mΩ/°C and is instantaneous and immune to any transient behavior of the device. The second eliminates the need for accurate measurement of the case temperature. The package's junction-to-case thermal resistance was determined by extrapolating the discrete thermal resistance data points in the plot to zero layer of thermal interface. An analytical expression was derived to guide the extrapolation and was validated by finite-element analysis simulations. The measurement procedure was tested using two different thermal interface materials. The difference between the two experimental measurements was within 24%, and both are in good agreement with the simulated result.

Power Device Interface Characterization With Low-Cost Thermal System Identification

This article develops a technique, requiring no dedicated temperature sensing calibration step, to rapidly characterize transient heat transfer in packaged, power semiconductor components. It is presented as an alternative to traditional step response characterization methods by exploiting the phase delay metric native to frequency response function (FRF) analysis in the field of system identification. This article presents the principles of power device physics and transient waveform analysis to identify the design space in which FRF data extracted from experiments are robust. Electronic circuitry is introduced, providing the needed, periodic heat actuation, and a measurement strategy leveraging direct processing of a temperature-sensitive electrical parameter (TSEP). The developed method is applied to make a key measurement confirming the high-frequency-only thermal FRF sensitivity to component die-attach condition. The measurement is shown to align with an output from a partial differential thermal model embedding a single, corrective scaling factor. Overall, this article highlights the emergent opportunity to measure a packaged power device’s transient thermal impedance with standard lab equipment and the ongoing opportunity to realize converter degradation self-sensing.

A Hybrid Model of Turn-Off Loss and Turn-Off Time for Junction Temperature Extraction

Temperature-sensitive electrical parameter (TSEP) approaches are widely employed in the junction temperature (T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">j</sub> ) extraction and prediction of power semiconductor devices. In this paper, the turn-off loss (E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</sub> ) and turn-off time (t <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</sub> ) are presented as temperature-sensitive electrical parameters. The abrupt change in the junction temperature of Insulated Gate Bipolar Transistor (IGBT) occurs during switching is proved. Common deficiencies in a single temperature-sensitive electrical parameter were considered, including the necessity of the collector currents exaction, the poor junction detection accuracy. Therefore, after the linear relationship between junction temperature and turn-off time, and turn-off loss is proved, a hybrid model based on turn-off loss (E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</sub> ) and turn-off time (t <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</sub> ) is proposed to extract junction temperature accurately. The experimental results show that the proposed method is with the advantages of high accuracy and strong anti-interference ability. Although some high-precision probes are required for parameter extraction, it indicates the internal mechanism of junction temperature mutation of the power device, and it is of great value for the reliability of the power devices that operate continuously.

Research on junction temperature detection method of power electronic devices based on turn-off time and turn-off loss

The temperature-sensitive electrical parameter (TSEP) method is widely used in the extraction and prediction of junction temperature (Tj) of power semiconductor devices. In this paper, turn-off loss (Eoff) and turn-off time (toff) are taken as temperature-sensitive electrical parameters. It is proved that the junction temperature of the insulated-gate bipolar transistor (IGBT) changes abruptly during switching. The common defects of a single temperature-sensitive electrical parameter, including collector current requirements and poor junction detection accuracy, are considered. Therefore, after proving the linear relationship between junction temperature, turn-off time, and turn-off loss, a hybrid model based on turn-off loss (Eoff) and turn-off time (toff) is proposed to accurately extract junction temperature. The experimental results show that this method has the advantages of high precision and strong anti-jamming ability.