Insulated Gate Bipolar Transistor Modules Research Articles

Effect of Asymmetric Layout of IGBT Modules on Reliability of Motor Drive Inverters

Power electronics inverters are one of the major failure sources in motor drive systems, and power devices are one of the main causes of the power electronics inverter failures. Typically, an insulated-gate bipolar transistor (IGBT) module has multiple power devices due to some technical and cost advantages. This kind of configurations could have an asymmetric internal layout, which may lead to different thermal loadings and thereby lifetime difference of the power devices. Therefore, both the power rating and the lifetime of inverters are limited by the most stressed device. However, generally common data are provided for all devices in the datasheet and this may cause improper design of the inverters in terms of the lifetime and the power rating. In this paper, an effect of an asymmetric layout of IGBT modules on the reliability of motor drive inverters is studied based on a three-phase motor drive application with a 600 V, 30 A, three-phase transfer molded IGBT module. The thermal impedances of six IGBTs are investigated and its effect on thermal loadings of power devices is studied under the given mission profile. Then, their lifetimes are estimated and compared. Finally, this effect is verified by the experiments.

Practical Research on VSC Prototype Based on IGBTs Serial Connected Technology

With the development of insulated gate bipolar transistor (IGBT) and pulsewidth modulation control strategy, the voltage source converter (VSC) is getting more and more popular, which can be used in high-voltage frequency converter, VSC-HVDC, FACTS, and custom power. In high voltage and high power applications, serial connection of IGBTs is a good solution to overcome the voltage limitation of the single IGBT. However, for using IGBTs in this way, a comprehensive range of issues need to be addressed, especially the static and dynamic voltage-sharing of each IGBT module. This paper presents the theoretical and practical study on how to use serial-connected IGBTs in a VSC, including adaptive dynamic voltage-balance strategy, voltage-balance circuit, power supply system, and valve vase electronics. A three-phase two-level VSC consisted of 6 arms multiplied by 12 serial-connected 3300 V IGBT modules is also developed. To test the performance of the VSC, pulse test of the one arm and inverter operation test of the whole VSC are carried out. The experimental results show that the maximum voltage imbalance is about 10%, the voltage shoots are less than 12%; and the VSC works stably, which indicates a solid foundation for industrial application.

Simplified Estimation of Junction Temperature Fluctuation at the Fundamental Frequency for IGBT Modules Considering Mission Profile

The junction temperature at the fundamental frequency cannot be ignored in a lifetime evaluation of insulated-gate bipolar transistors (IGBTs) with a long-term mission profile. Therefore, it is very important in terms of calculation speed and accuracy to simplify the loss curve when calculating the thermal fluctuation at the fundamental frequency. This paper proposes a mathematical analysis method for the junction temperature fluctuation at the fundamental frequency based on an equivalent sinusoidal half-wave loss. The dynamic and static parameters of the devices are tested by an experimental platform, and accurate device loss models are established through a case study of a 1.5 MW direct-drive wind turbine grid-connected model. The accuracy of the proposed calculation model is compared with that of a time-domain simulation and the two-step loss pulse method. Considering different output frequencies, the accuracy of the proposed method is further discussed. Based on actual wind speed data, the proposed method is used to calculate the junction temperature of an IGBT module in a grid-side converter. The results show that the proposed method can improve the accuracy of the reliability evaluation of wind power converters.

Condition Monitoring of IGBT Modules Based on Changes of Thermal Characteristics

Condition monitoring (CM) of insulated-gate bipolar transistor (IGBT) modules is significant for improving power converter reliability and reducing the loss caused by IGBT failure. In this paper, we present an advanced method to evaluate the aging condition of an IGBT based on the changes of thermal characteristics in the module, which can be described by the junction and case temperatures. The variation of the case temperature distribution is used to monitor the solder fatigue. The estimated level of solder fatigue is used to update the parameters in the electrical-thermal model. Then, the junction temperature can be accurately estimated by the updated electrical-thermal model. The difference between junction temperatures estimated from the updated model and temperature-sensitive electrical parameter (TSEP) is utilized to monitor the aging of bond wires. The proposed CM method permits both of health level evaluation and accurate junction temperature estimation of IGBT in real time to prevent catastrophic failure caused by defective modules. The experimental results on a commercialized IGBT product have validated the feasibility of the proposed method.

Characterizations of a Proposed 3300-V Press-Pack IGBT Module Using Nanosilver Paste for High-Voltage Applications

Nanosilver paste was used in this study as a die-attachment material for 3300-V power chips to eliminate the pressure contact of a press-pack power module. The proposed insulated-gate bipolar transistor (IGBT) module was named as a sinter-pack IGBT module. We studied the effect of the assisted hydrostatic pressure, i.e., 0, 1, 3, 5, and 10 MPa, on the mechanical, thermal, and electrical performance of the as-sintered silver joints. As the pressure increased, the die-shear strength increased, and the thermal impedance decreased, as expected. The electrical properties of the assembly using the sintered silver were comparable with those of the chip with the same power rating, which proved the feasibility of the as-sintered IGBT specimens. The thermal resistance of the sinter-pack IGBT module decreased by 15.8% compared with that of the commercial press-pack one with the same power rating. The static electrical properties of the sinter-pack IGBT module were consistent with those of the commercial press-pack one, which further proved the feasibility of the sinter-pack IGBT module.

Impedance Measurement of Traction Network and Electric Train for Stability Analysis in High-Speed Railways

Instability and oscillation issues have frequently occurred in high-speed railways due to the impedance mismatch versus frequency between the four-quadrant converter (4QC)-based high-speed train and the traction network (hereinafter train–network). However, solely utilizing the mathematical deduction to quantify the impedances seems to be difficult owing to unknown detailed parameters of both traction network and electric train. This paper proposes a method to measure the equivalent impedances of the traction network and the 4QC of the electric train in the stationary frame for stability analysis. A disturbance circuit consisting of antiparallel insulated gate bipolar transistor (IGBT) modules and an excitation load is adopted by means of the pulsewidth modulation (PWM) signal to drive the IGBTs. Consequently, a desired broad spectral excitation is then generated to measure the output impedance of the traction network. When injecting the harmonics twice, which are linearly independent at the same frequency, the input impedance of the 4QC can be calculated at the corresponding frequency considering the frequency-coupled effect. The proposed method shows a good measurement accuracy. Additionally, the stability and oscillation issues of the train–network system can be then identified using measured impedances. Both simulation and experimental results validate the effectiveness of the proposed measurement method.

Prognostics of IGBT modules based on the approach of particle filtering

In the present work, a prognostic model combining model-based and data-driven techniques was developed and validated for dynamic life prediction of insulated gate bipolar transistor (IGBT) modules under power cycling conditions. The prognostic model integrates both anomaly detection based on semi-supervised machine learning and remaining useful life (RUL) estimation based on the particle filter (PF) approach. A range of healthy failure precursor data was predefined as labeled training data and machine learning techniques including principal component analysis (PCA) for feature extraction, and k-means clustering for anomaly detection were implemented. The clustering technique partitioned the predefined healthy data points into healthy clusters using a singular-value-weighted distance measure. The safety margin between a healthy distribution of distances between healthy data points within each cluster, and a test distribution of distances between a test data point and all the healthy data points within each cluster, was calculated to determine the affiliation of a test data point to the healthy cluster. A failure precursor process model incorporating the crack propagation physics law, the Paris Equation, and a measurement model was developed facilitating a sampling importance resampling (SIR) filter for RUL estimation. The developed prognostic model was validated on the degradation data from literature sources reporting IGBT power cycling test results to demonstrate its robustness.

New Energy Empowerment Using Kernel Principal Component Analysis in Insulated Gate Bipolar Transistors Module Monitoring

At present, energy exhausted and environmental pollution are important issues, vigorously promoting new energy and improving the utilization efficiency and management level of new energy is an important way to achieve sustainable social development. Insulated gate bipolar transistors are important components in power converters and are widely used in new energy generation, new energy vehicles, high-speed rail and industrial production. However, the power module’s age is related to all aspects of its performance change, precluding the use of a single parameter to fully and accurately express the aging state. To monitor this state and evaluate the aging state, this study presents a method to analyze and process the state data of Insulated gate bipolar transistors power module aging tests using kernel principal component analysis and establishes a multi-dimensional grey model to evaluate the power module aging state. Using the temperature cycle aging test platform, the 7000 temperature cycling tests are implemented to accelerate the age of the power module to failure, the dynamic parameters of the power modules are measured after every 1000 cycles. During the accelerated aging process, the case temperature change rate, collector-emitter voltage drop Vce(SAT) and Miller platform of the gate signal of Vge are found to exhibit different variation trends at different aging stages. The result showed that multiple parameters are combined into integrated attributes to enable more accurate implementation of the state monitoring of power modules using the proposed method, which improves the status monitoring level of Insulated gate bipolar transistors modules. The proposed method is beneficial to improve the utilization efficiency and new energy source management level.

A unified MMC reliability evaluation based on physics-of-failure and SM lifetime correlation

The reliability of a modular multilevel converter (MMC) is determined both by the component lifetime distribution and the MMC structure. In this paper, a unified submodule (SM) component lifetime is estimated based on the physics- of- failure, and the overall reliability of the MMC system is evaluated considering the SM lifetime correlation. First, the component lifetime estimation is performed in three sub-steps. (a) The current stress of each component, i.e., the insulated gate bipolar transistor modules (IGBTs) and capacitors, is computed according to the working principle of the MMC. (b) The core temperatures of the components are calculated using thermal equivalent networks. For the IGBTs, the thermal cycles are extracted to compute the cumulative damage. (c) The lifetime of each device is estimated in a static state using the lifetime model and damage model. Second, the lifetime Weibull distribution of each component is obtained using the Monte Carlo method. This distribution links the component lifetime estimation and MMC reliability analysis. Finally, considering the SM lifetime correlation, the overall reliability of an MMC system with redundancy is evaluated using a Copula function. The reasons for the impact of SM lifetime correlation on MMC reliability are revealed in a case study.

A Multichip Phase-Leg IGBT Module Using Nanosilver Paste by Pressureless Sintering in Formic Acid Atmosphere

This paper proposed a new approach to attach power devices on nonmetallized direct bonding copper (DBC) substrates by pressureless sintering of nanosilver paste in poor-oxygen sintering atmosphere and formic acid reduction atmosphere. The average shear strength of die-attach joints could reach 25 MPa, and the copper oxidation issue of the nonmetallized DBC substrates was avoided. Based on the pressureless sintering approach of nanosilver paste, insulated-gate bipolar transistor (IGBT) modules were prototyped to verify the feasibility of this approach for mass production of power modules. The electrical and thermal characteristics of the IGBT modules bonded with sintered nanosilver were then compared with those of the commercialized ones using Pb92.5Sn5Ag2.5 solder alloy. This approach could extend the applications to bonding power devices on nonmetallized DBC substrates by nanosilver paste, and guide fabricating power modules in a mass productive, low facility costs, and high-yield way.

On <inline-formula> <tex-math notation="LaTeX">$V_{{\text{ce}}}$</tex-math> </inline-formula> Method: <italic>In Situ</italic> Temperature Estimation and Aging Detection of High-Current IGBT Modules Used in Magnet Power Supplies for Particle Accelerators

Magnet power supplies used in particle accelerators are a specialized application of power electronics that require long lifetime operation with no unscheduled interruptions and high output current precision. In this paper, the ${V_{{\rm{ce}}}} $ method with sensing current is considered for the estimation of the junction temperature and the aging detection of high-current insulated gate bipolar transistor (IGBT) modules used in this specialized application. First, sensitivity analysis of the sensing current and the gate–emitter voltage are documented to quantify their impact on the precision of the ${V_{{\rm{ce}}}} $ method for high-current modules independently of the application of interest. Two measuring circuits offering ease of calibration and reduced number of components are proposed but their applicability is not limited to this application. Their performance is tested on a 1.6 kA IGBT module that exhibits the highest current ratings documented for the ${V_{{\rm{ce}}}} $ method with sensing current. The test is carried out at a switching frequency of 6.5 kHz using an experimental set-up that emulates a phase leg of the considered power supply. The ${V_{{\rm{ce}}}} $ method with sensing current is evaluated for the aging detection of high-current IGBT modules in general and its effectiveness for the specialized application is verified experimentally.

Investigation of a rectangular heat pipe radiator with parallel heat flow structure for cooling high-power IGBT modules

The thermal management of insulated-gate bipolar transistor (IGBT) modules is a critical issue in the field of power electronics. According to the minimum thermal resistance principle, this study proposed a rectangular heat pipe radiator with parallel heat flow structure that can be used for cooling two 1700 V/1000 A IGBT modules. The prototypes of typical and novel heat pipe radiators were produced to validate the heat transfer enhancement of the novel structure. Performance evaluation and analysis were numerically and experimentally carried out, and the numerical results agreed well with the experimental data. Parametric studies were performed to analyze the effects of inlet air temperature, air volume, and heat load on the heat dissipation capability. The study found that the novel heat pipe radiator has a good start-up characteristic due to the parallel heat flow structure. Moreover, the performance enhancement of the novel heat pipe radiator is obvious at large heat loads. Experiment results show that the two IGBT modules with 3500 W could be cooled down to 67.8 °C when the air volume is 450 m3 h−1, which is 8.9% lower than that of a typical heat pipe radiator. The proposed novel structure improves thermal performance of the novel heat pipe radiator by significantly decreasing its thermal resistance by 22% in comparison with that of a typical heat pipe radiator.

Method of junction temperature estimation and over temperature protection used for electric vehicle's IGBT power modules

Abstracts High-power insulated gate bipolar transistor (IGBT) modules are widely used in power electronic systems, their system reliability is received more and more attention. The junction temperature of power devices is an important factor affecting reliability of power electronic systems. For electric vehicle applications, this paper proposes a method of junction temperature estimation and over temperature protection is used for electric vehicle's IGBT power modules. According to two junction temperature estimation methods, one is based on the thermal impedance model of IGBT modules, and the other is based on the relationship between the negative temperature coefficient (NTC) thermistor temperature and the chip temperature inside modules, two estimated junction temperatures can be obtained. Under different working conditions, the two estimated junction temperature ratios are adjusted to obtain an optimal estimated junction temperature. Based on the junction temperature estimation, several temperature thresholds are set. When the temperature reaches the threshold value, the motor drive control is used to perform effective over temperature protection to prevent the IGBT modules of the electric vehicle inverter from being ineffective due to the excessive junction temperature and resulting in the loss of vehicle power.

Online condition monitoring of IGBT modules using voltage change rate identification

As insulated gate bipolar transistors (IGBTs) have gained an important status in a wide range of applications, reliability, and availability of these units are of paramount importance to meet stringent requirements spelled in aviation and industrial standards. Reliability of a power converter is mainly verbalized by the failure rate of power modules. Hence, monitoring IGBTs degradation is very crucial to give early sign of power-module-related failures in power converters. This paper proposes a new potential precursor parameter for IGBTs based on voltage change rate to detect early failure of power modules. The proposed method pays more attention to power modules with chip solder fatigue and bond-wire lift off as a major failure mechanism. An experimental setup using an accelerated power cycling machine is constructed to trigger degradations and failures on several IGBT modules. The experimental results indicate that voltage change rates of the IGBT modules decrease with ageing over time. It is found that the local damage induced by ageing over time changes the parasitic capacitances of an IGBT that leads to a decrease of the voltage change rate of the device.

On-line fault diagnosis model for locomotive traction inverter based on wavelet transform and support vector machine

A traction inverter is the power source for rail transit vehicles. An insulated-gate bipolar transistor (IGBT) is the primary component of a traction inverter. IGBT faults can cause serious problems in locomotive power supply systems. The disadvantage of traditional fault detection methods for IGBT modules is a lack of real-time processing and high efficiency. An on-line fault diagnosis method based on a wavelet transform and multi-classification support vector machine (multi-SVM) is proposed for IGBT faults. Wavelet decomposition is used to process fault current signals, and energy vectors are constructed. Multi-SVM is used to establish a fault recognition model. The validity of this method is verified by simulations with MATLAB/Simulink.

Reliability modeling of MMC-based flexible interconnection controller considering the uncertainty of current loading

The flexible interconnection controller (FIC) is a type of power electronic device based on Insulated Gate Bipolar Transistors (IGBT) modules, which is applied to electrical distribution systems to realize the flexible control of power flow. The reliability of this device plays an important role in the reliable and continuous operation of the active distribution system. In this paper, a reliability model of FIC which consists of three modular multilevel converters (MMCs) is proposed, considering the uncertainty of current loading. First, the structure and operating modes of FIC are analyzed. Based on the fault tree analysis, the reliability model of single-terminal MMC is established. Next, considering the impact of random current loading on the IGBT modules’ reliability, Monte Carlo simulation is used to obtain the loading expectation correction factor, thus the equivalent reliability model of IGBT module is built. Furthermore, the state space model of FIC is established, and the analytical method based on Markov chain is used to solve it. Taking the improved three IEEE33 node feeder groups as the testing system, the equivalent reliability indices of IGBT module as well as the converter reliability of the three terminals of MMC are obtained via simulation, and based on which, the probabilities and average durations of FIC’s eight states are calculated to verify the proposed model.

IGBT junction and coolant temperature estimation by thermal model

The capability of IGBT (Insulated Gate Bipolar Transistor) to handle heat is one of its main limitations of high power application. This paper aims to study an IGBT thermal model under flow cooling condition and estimate the IGBT module junction and coolant temperature. Firstly, this paper studies the IGBT module internal sandwich structure and calculates the thermal resistance and thermal capacitor for each layer using a 1D physical model. Then a Cauer electric model is built for the IGBT module to evaluate the thermal constant time of the model. The liquid cooling method is applied in this project for fast cooling and the thermal parameters are studied and measured since this cooling method involves both solid and liquid. In order to estimate the junction temperature, the sensing temperature from NTC (Negative temperature coefficient) resistor inside the module is used as reference temperature. The equivalent thermal models, also named Foster model, from both junction to NTC and NTC to coolant are built, respectively. With these thermal models, the junction and coolant temperature estimation methods are derived. For the purpose of making the estimation accurate, the thermal coupling effect is carefully studied. Finally, the thermal model is verified by inverter application with current steps sweeping; the estimated temperature is compared with thermal camera measurement result which demonstrates good accuracy of the thermal model. The estimated coolant temperature is also well matched with thermocouple measurement result.

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.

Lifetime prediction model for electric vehicle IGBT modules under driving conditions

ABSTRACTIn order to study the effect of road conditions and electric vehicle (EV) running speed on useful lifespan, a model for predicting the lifespans of insulated gate bipolar transistor (IGBT) modules of EVs is proposed. The life cycle prediction model was formulated according to an analysis of the working state, power loss, and junction temperature fluctuation of IGBT modules under driving conditions and was implemented using MATLAB software. Then, the lifetime prediction model was used to calculate the life mileage of an EV under the New European Driving Cycle (NEDC); the results predict a life mileage of 182.98 km. The simulation results of junction temperatures under the NEDC conditions indicate that the acceleration process of EVs has a substantial influence on the lifetime of IGBT modules. The lifetime prediction model was also used to analyze the relationship between the speed of EVs and the lifetime of IGBT modules. The IGBT modules have a maximum life mileage at a constant speed of 70 km/h; life mileage declines gradually as the speed increases or decreases. This lifetime prediction model can be used to predict lifetime of EV IGBT modules under driving conditions and analyze the effect of driving conditions on lifespan effectively.

Advanced Active Gate Drive for Switching Performance Improvement and Overvoltage Protection of High-Power IGBTs

This paper presents a new active gate drive (AGD) for switching performance improvement and overvoltage protection of high-power insulated gate bipolar transistors (IGBTs). In addition to the conventional gate drive (CGD) based on fixed voltage sources and fixed gate drive resistors, the proposed AGD has a complementary current source to provide extra gate drive current into the gate. Specific transient switching stages of the IGBT can be therefore accelerated, leading to higher switching speed and lower switching loss of the IGBT. Additionally, the turn-off voltage overshoot of the IGBT can be controlled at a preset reference value with a fast closed-loop overvoltage protection circuit. Moreover, the switching speed of the IGBT, including the turn-on/off delay times and the turn-on/off voltage slopes, can be effectively regulated with an adaptive switching speed control method. Accordingly, the gate drive is capable of operating the IGBT at specified delay times and fixed voltage slopes when varying the switching conditions (e.g., temperature, load current). The operation principle of the proposed AGD and control concept are presented. By comparing with the CGD, the proposed method is experimentally verified on a 3.3 kV/1.5 kA IGBT module in both double-pulse and multipulse tests.