High Power Insulated Gate Bipolar Transistor Modules Research Articles

Multi-physics coupling analysis of high-power IGBT module bonding wires fault considering stray inductance of main circuit

The insulated gate bipolar transistor (IGBT) module is subjected to unbalanced electric-thermal stress for a long time due to its own turn-on and turn-off, the fluctuation of processing power and the change of external operating environment, resulting in fatigue failure. And there is a strong coupling effect between its electrical, temperature and mechanical properties. At the same time, the fatigue failure of IGBT module is also the result of multi-physical field coupling. This paper reveals the influence mechanism of main circuit stray inductance on the electric-thermal-stress coupling characteristics of high power IGBT module bonding wires fault in the context of mine-used inverter application. First, the inverter main circuit topology model considering stray inductance is constructed, and the loss value of the power chip is obtained based on extracting the busbar stray inductance and establishing the IGBT module behavior model, and the validity of the results is verified. Secondly, the package structure model of IGBT module is established and the failure analysis boundary conditions are determined, and then the joint circuit-finite element method is used to reveal the operation behavior characteristics of IGBT module under the combined action of multi-physical fields. Finally, the influence of main circuit stray inductance on the multi-physical field coupling characteristics of IGBT module and its change law are compared and analyzed under the bonding wires fault condition to study the causes of fatigue failure of IGBT module.

Dynamic IGBT Three-Dimensional Thermal Network Model Considering Base Solder Degradation and Thermal Coupling Between IGBT Chips

With the development of power electronic technology, the thermal characteristics of high-power insulated gate bipolar transistor (IGBT) module are vital information for thermal management of power electronic equipment, reliability analysis, and thermal design of power electronic system. However, the present commonly used lumped thermal network model based on thermal resistance and heat capacity still has some limitations in accurately predicting the junction temperature of IGBT modules, significantly once considering the degradation of base solder in high-power IGBT modules. In this paper, the thermal behavior of high-power IGBT chips under different base solder degradation is studied by the finite element method (FEM). The results show that the degradation of the base solder has effects on the thermal impedance between the junction and the case, which should be fastidiously thought about within the thermal network model modeling. As a result, a dynamic three-dimensional thermal network model that takes into account the thermal interaction between IGBT chips, as well as the degradation of the base solder, is proposed in this paper. The proposed thermal network model can estimate the junction temperature of a high-power IGBT module correctly and fast based on the real degradation of the base solder. Finally, finite element simulation and experimental findings are used to validate the proposed dynamic three-dimensional thermal network model. The results show that the dynamic three-dimensional thermal network model has comparable accuracy to finite element simulation and test results. At the same time, the dynamic three-dimensional thermal network model responds faster than the finite element simulation.

Warping model of high-power IGBT modules subjected to reflow soldering process

High-power insulated gate bipolar transistor (IGBT) modules are the key devices for energy change and transmission. Reflow soldering process is a crucial process in IGBT module packaging manufacture. Residual stress and warpage of IGBT modules are induced after soldering, which can lead to degradation of device performance and working life. Combining frame-based baseplate and the key material properties of AlSiC at different temperatures, latent heat and viscoplastic intrinsic models of the solder, this study established a finite element (FE) model of the reflow soldering process of IGBT modules to predict the warpage and residual stresses. Reflow soldering experiments of IGBT modules were conducted to examine the shape of the lower surface of the baseplate before and after the soldering process, and are used to verify the modeling results. The model shows a good agreement with the experimental with an error of 5.46%. The FE model will contribute to the optimization of reflow soldering process and package structure of IGBT module.

Numerical simulation and optimization of heat dissipation structure for high power insulated gate bipolar transistor (IGBT)

With the increasing integration level of IGBT components, heat dissipation capacity determines whether its working state is stable. The third-generation semiconductor chips are expected to be made of SiC or GaN materials, with lower power loss and higher thermostability. Currently, the widely used backplane heat dissipation schemes cannot meet the heat dissipation requirements of high-power IGBT modules. In this study, an aluminium alloy shell with an AlN column is proposed to replace the traditional plastic shell to further improve the heat dissipation of IGBT devices. 180°C is set as the expected maximum temperature of the module, and finite element modelling and analysis of the heat dissipation structure of the IGBT device is carried out. Four types of design schemes are compared and the heat dissipation structure is optimized. AlN heat-transfer blocks and Ag sintering are introduced to realise the novel design. The results show that traditional single-side heat dissipation can not meet the requirements. The improved double-side dissipation scheme meets the requirement when the heat sink fin height is more than 15mm. And the optimized heat sink shall have 14 fins of 20mm in height. The results of this study can provide a reference for the thermal management and design of high-power third-generation semiconductor devices.

Analysis of Reverse Recovery Characteristics of Anti-parallel Diode

Insulated gate bipolar transistor (IGBT) is widely used in various renewable green energy systems such as wind power generation and solar power generation at present. High-power IGBT modules usually include IGBT chips and anti-parallel diodes, and the transient characteristics of anti-parallel diodes will affect the external port characteristics of IGBT modules. Based on semiconductor physics and diode basic structure, this paper analyzes four stages of diode reverse recovery process, and describes the change process of turn-off time and stored charge by a step recovery process. Finally, the voltage and current waveforms of diode reverse recovery process are simulated and verified for a certain IGBT module.

Prediction Method of Driving Strategy of High-Power IGBT Module Based on MEA-BP Neural Network

An insulated gate bipolar transistor (IGBT) driver is crucial for improving the reliability of a power electronics system. This paper proposes a method for predicting the optimal driving strategy of high-power IGBT module based on backpropagation neural network optimized by the mind evolutionary algorithm in order to solve the problem of compromise among switching loss, switching time and overshoot and achieve a good driving effect. The three regions of switching transitions are analyzed based on the switching characteristics of the IGBT module. Neural networks are established to predict turn-on and turn-off driving strategies for variable gate resistance active gate driver of the IGBT module. The mind evolutionary algorithm is used to optimize the weights and biases of the neural networks so that the optimal weights and biases can be obtained. In order to verify the effectiveness of the driving strategy prediction method proposed in this paper, experiments are carried out for 4500V/900A the IGBT module. Compared to the conventional gate driver, the predicted driving strategies reduce the turn-on energy loss, turn-on time, overcurrent, comprehensive evaluation method, turn-on delay time and tail voltage duration by 59.31%, 46.38%, 36.99%, 65.65%, 1.9 μs, 2.9 μs, respectively. It was also found that the Planar-IGBT turn-off process was rarely affected by the gate resistance. The proposed method in this paper can be used not only for the guidance of the driving strategy determination of high-power the IGBT module driver, but also for the driver circuit improvement in the design process.

Thermal mapping at the cell level of chips in power modules through the silicone gel using thermoreflectance

Silicone gel is used in power electronics in order to provide a chemical protection and dielectric insulation in insulated gate bipolar transistor (IGBT) power modules. This gel prevents the direct mapping of surface temperature measurements of the component by classical infrared means. The temperature maps inside IGBT modules are usually performed after removal of the silicone gel which does not allow their operation in real environment. In this paper, we explore the ability of thermoreflectance to overcome this limitation in measuring the temperature surface of an IGBT chip through the silicone gel. Thermoreflectance is a non-contact technique, which measures temperature variation through reflectivity variation measurement. Using a “mean” calibration coefficient determinates from optical fiber thermal measurements, thermal images of IGBT modules with and without silicone gel can be compared. Preliminary results indicate that thermoreflectance enables the measurement of surface temperature change on high power IGBT modules with silicone gel and temperature distribution is affected by the presence of the gel.

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.

Investigation and Classification of Short-Circuit Failure Modes Based on Three-Dimensional Safe Operating Area for High-Power IGBT Modules

Insulated-gate bipolar transistor (IGBT) short-circuit failure modes have been under research for many years, successfully paving the way for device short-circuit ruggedness improvement. The aim of this paper is to classify and discuss recent contributions about IGBT short-circuit failure modes, in order to establish the current state of the art and trends in this area. First, the concept of 3-D safe operating area is proposed as the IGBT's operational boundary to divide the device short-circuit failure modes into short-circuit VDC/Vrated-ISC SOA limiting and short-circuit endurance time limiting groups. Then, the discussion is centered on currently reported IGBT short-circuit failure modes in terms of their relationships with the device 3-D short-circuit safe operating area (3D-SCSOA) characteristics. In addition, further investigation on the interaction of 3D-SCSOA characteristics is implemented to motivate advanced contributions in future dependence research of device short-circuit failure modes on temperature. Consequently, a comprehensive and thoughtful review of where the development of short-circuit failure mode research works of IGBT stands and is heading is provided.

Analysis on the difference of the characteristic between high power IGBT modules and press pack IGBTs

The insulated gate bipolar transistor (IGBT) has been widely employed in such applications as alternate current motors and inverters for its lower driving power and lower on-state voltage. IGBT modules and press pack IGBTs are the most commonly used packaging for high-voltage and high-power-density applications. The difference in the packaging style and working conditions between IGBT modules and press pack IGBTs creates distinctions in, for instance, the thermal characteristics and reliability. Those distinctions lead to different applications and working conditions. In this paper, the development of IGBT devices has been reviewed, including the distinction of IGBT modules and press pack IGBTs in packaging style. Most importantly, the thermal and reliability characteristics have been compared in detail and the applications that are most suitable for IGBT modules and press pack IGBTs were outlined. The comparison of the thermal characteristics, reliability and applications provides guidance for users to take full advantage of the devices according to their requirements.

Numerical Prediction of Solder Fatigue Life in a High Power IGBT Module Using Ribbon Bonding

This study focused on predicting the fatigue life of an insulated gate bipolar transistor (IGBT) power module for electric locomotives. The effects of different wiring technologies, including aluminum wires, copper wires, aluminum ribbons, and copper ribbons, on solder fatigue life were investigated to meet the high power requirement of the IGBT module. The module’s temperature distribution and solder fatigue behavior were investigated through coupled electro-thermo-mechanical analysis based on the finite element method. The ribbons attained a chip junction temperature that was 30° C lower than that attained with conventional round wires. The ribbons also exhibited a lower plastic strain in comparison with the wires. However, the difference in plastic strain and junction temperature among the different ribbon materials was relatively small. The ribbons also exhibited different crack propagation behaviors relative to the wires. For the wires, the cracks initiated at the outmost edge of the solder, whereas for the ribbons, the cracks grew in the solder layer beneath the ribbons. Comparison of fatigue failure areas indicated that ribbon bonding technology could substantially enhance the fatigue life of IGBT modules and be a potential candidate for high power modules.

Influence of moisture on dielectric condition of high power Insulated Gate Bipolar Transistor modules

Moisture in a high power Insulated Gate Bipolar Transistor (IGBT) module raises serious concern on component and system level reliability. Employing diagnostic test methods on high power IGBT modules might provide an opportunity in detection and estimation of moisture, however has not received wide attention. This paper investigates on understanding the influence of moisture in high power IGBT modules through time and frequency dependent dielectric response measurements and partial discharge analysis. The moisture in the main insulation of an IGBT module under DC excitation produces a sharp rise in its response current introducing deviation in their respective time dependent dielectric properties. Alternatively, the frequency dependent dielectric response measurements under wide frequencies provide more information than their DC counterpart. This method enables discrimination of various defects such as moisture, physical defects, etc., thereby revealing a clear picture about the actual status. In particular, the lower frequencies reveal longer range ion movements, hence could be used for more accurate estimation of moisture. The higher frequencies though not accurate in moisture estimation reveal deviation in the material properties. These deviations alter the apparent dielectric characteristics such as loss factor, permittivity, etc., of the IGBT samples which becomes clear through simple comparative analysis. In conclusion, the findings in this paper might help in understanding the influence of moisture over the dielectric integrity of a high power IGBT module. Additionally, the permissible or acceptable level of moisture which might act as a threshold to initiate necessary precautionary measures could be subsequently developed.

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 3-D-Lumped Thermal Network Model for Long-Term Load Profiles Analysis in High-Power IGBT Modules

The conventional $RC$ -lumped thermal networks are widely used to estimate the temperature of power devices, but they lack of accuracy in addressing detailed thermal behaviors/couplings in different locations and layers of the high-power insulated gate bipolar transistor (IGBT) modules. On the other hand, a finite-element (FE)-based simulation is the other method, which is often used to analyze the steady-state thermal distribution of IGBT modules, but it is not possible to be used for a long-term analysis of load profiles of power converter, which is needed for reliability assessments and better thermal design. This paper proposes a novel 3-D $RC$ -lumped thermal network for the high-power IGBT modules. The thermal coupling effects among the chips and among the critical layers are modeled, and boundary conditions, including the cooling conditions, are also considered. It is demonstrated that the proposed thermal model enables both accurate and fast temperature estimation of high-power IGBT modules in the real loading conditions of the converter while maintaining the critical details of the thermal dynamics and thermal distribution. The proposed thermal model is verified by both the FE-based simulation and the experimental results.

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.

Dynamic Characterization of Parallel-Connected High-Power IGBT Modules

In high-power converter design, insulated gate bipolar transistor (IGBT) modules are often operated in parallel to reach high output currents. Evaluating the electrical and thermal behavior of the parallel IGBTs is crucial for the design and reliable operation of converter systems. This paper investigates the static and dynamic characterization of parallel IGBTs and the influence of the electrical parameters on the IGBT behavior. Si-based IGBT power modules with voltage rating of 4.5 kV and current rating of 1 kA are used for the experimental evaluation of module parallel connections. Parallel-connected modules have been driven by several commercial IGBT gate units at various dc-link voltages and current levels and with different temperatures. The tested IGBT gate units show good current sharing performance between the two parallel modules. Other important influencing factors such as busbar design layout, stray inductance variation, and gate driving are also investigated for parallel connections of IGBT modules. Finally, the switching energy of the parallel modules is extracted for IGBTs and diodes under different conditions.

Improving Power Converter Reliability: Online Monitoring of High-Power IGBT Modules

The real-time junction temperature monitoring of a high-power insulated-gate bipolar transistor (IGBT) module is important to increase the overall reliability of power converters for industrial applications. This article proposes a new method to measure the on-state collector-emitter voltage of a high-power IGBT module during converter operation, which may play a vital role in improving the reliability of the power converters. The measured voltage is used to estimate the module average junction temperature of the high and low-voltage side of a half-bridge IGBT separately in every fundamental cycle of the current by calibrating them at load current. The measurement is very accurate and also measures the voltage at the middle of a pulse-width modulation (PWM) switching. A major objective is that this method is designed to be implemented in real applications. The performance of this technique is measured in a wind power converter at a low fundamental frequency. To illustrate more, the test method as well as the performance of the measurement circuit are also presented. This measurement is also useful to indicate failure mechanisms such as bond wire lift-off and solder layer degradation. The measurements of and rise in the junction temperature after five million cycles of normal operation of the converter are also presented.