IGBT Modules Research Articles

Optimized selection of materials for IGBT module packaging

This paper examines the impact of various packaging materials on the IGBT module's thermal characteristics. A 3D finite element method (FEM) model of the studied IGBT module is created and validated by experimental tests. The materials used in the baseplate and the insulation layer of the IGBT module are then replaced with various materials to investigate how different material combinations affect the thermal performance. The obtained thermal performance of different materials is placed next to other criteria (mechanical strengths, least square of CTE mismatches, cost, and weight) to be ranked by the TOPSIS multi-criteria decision-making method based on the given objective weights. The results showed that the three combinations of AlSiC/AlN, W/Si3N4 and AlSiC/Si3N4 have the best overall performance and are ranked first to third, respectively. The frequently used material pair Cu/Al2O3 achieved 14th place indicating that it performs poorly in comparison to the other alternatives.

A thermal network model for monitoring IGBT chip solder degradation based on feedback PI control

Under long-term thermal cycles, the solder layers in IGBT modules degrade inevitably, which affects their heat dissipation performance and eventually leads to the failure of IGBT modules. In order to monitor the degradation degree of the IGBT chip solder layers according to the junction temperature, a thermal network model for monitoring the IGBT chip solder degradation based on feedback PI control is proposed. Firstly, the finite element simulation model of the IGBT module is established and the degradation degrees of the chip solder layers are defined in the simulation model. Then the thermal network model is extracted according to the finite element simulation model and the thermal impedance functions are fitted from the different power loss and chip solder degradation degrees. Meanwhile, a control loop with PI controller is established to regulate the thermal impedances. Finally, the accuracy of the proposed thermal network based on feedback PI control for chip solder degradation monitoring and junction temperature calculation is verified under different chip solder degradation degrees.

Condition monitoring indicators for Si and SiC power modules

The reliability of power modules plays a crucial role in developing safer and smarter generations of electric vehicles. Condition monitoring represents a possible solution to predict the possible occurrence of catastrophic failures and avoid unexpected breakdowns. More specifically, power modules for inverter applications are a technology requiring condition monitoring indicators to detect ongoing degradation mechanisms. In this work, both silicon IGBT and silicon carbide MOSFET power modules are thermally stressed through the application of a pulsed direct current until reaching end-of-life limits. As a result, two main failure mechanisms occurring at package level are observed: chip solder degradation and bond-wire damages. In addition, on-state voltage, junction temperature, and thermal resistance are measured during the power cycling as parameters to monitor the device states of health. After the test, the chip solder conditions and bond-wires robustness are checked through scanning acoustic microscope images and optical inspections, respectively. The novelty of this work lies in refining and comparing health indicators for silicon and silicon carbide power modules.

Analysis, design, and minimum phase selection of high power interleaved DC–DC converter

SummaryThe primary use of interleaved bidirectional DC–DC converters (IBC) is for high current applications due to the inherent property of ripple cancellation, high redundancy, and improved efficiency. Proper analysis and design are required to improve the power density and reduce the cost of the ‐phase IBC. Ripple current analysis plays a vital role in choosing the inductor and filter capacitors to minimize the size of an IBC. This paper presents the simple and generalized formulas for the current ripple minimization of ‐phase IBC. Also, the inductor is designed with two different core materials, namely, Ferrite and Sendust. It is observed that the area product and weight of the magnetics have been reduced by 22% and 23%, respectively, for Sendust core in comparison with the Ferrite core. Furthermore, a discussion regarding the thermal analysis of IGBT modules to select an appropriate heat sink is stated. Moreover, the minimum phase selection has been proposed by considering several constraints such as area product of the core, discrete components size based on ripple analysis, cost of all components, and converter efficiency. The prototype of the selected minimum phase IBC has been developed and tested for a 7.5 kW power level using TMS320F28335.

ЕКСПЕРИМЕНТАЛЬНІ ДОСЛІДЖЕННЯ КОНТРОЛЕРА ДЛЯ КЕРУВАННЯ ТЯГОВИМ ЕЛЕКРОДВИГУНОМ НА ПОСТІЙНИХ МАГНІТАХ

The controller of traction electric motors on permanent magnets for vehicles in which the power transistor converter is made on the modified IGBT modules with the improved characteristics is described in this work. The use of these modules, which are widely used today in semiconductor devices of modern dual-use technology, allows to reduce the size and weight of the converter, simplify the cooling system, increase efficiency and reliability of the semiconductor converter and electric drive in general due to harsh operating conditions. Bench tests of the experimental sample of the semiconductor converter and the microprocessor control system in various operating modes, including at the maximum load corresponding to real operating conditions are made and carried out. As a result of tests, it was determined that the technical characteristics of the controller meet the requirements of such devices. The created semiconductor controller on IGBT modified modules can be used to control motors on permanent magnets and motor wheels with a nominal power of 40-50 kW, maximum - 100 kW. References 11, figures 8, tables 4.

Junction-to-Case Thermal Resistance Measurement and Analysis of Press-Pack IGBTs Under Double-Side Cooling Condition

Junction-to-case thermal resistance <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">thjc</sub> measurement under a double-side cooling condition of press-pack IGBTs (PP IGBTs) is a great challenge since the heat flow through the two heat paths is hard to be accurately extracted. In this article, an indirect method determining the proportion of heat dissipation on both sides only by temperature measurement is proposed to simultaneously measure two single-sided <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">thjc</sub> of PP IGBTs under the double-side cooling condition, and it is performed with 4500 V/3000 A PP IGBTs. The test results show that the measured <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">thjc</sub> is not a fixed value but is related to the load current used in the test, it increases as the load current increases, which is different from the traditional wire-bonded IGBT module. A thermomechanical bidirectional coupling finite element model is built to explain the impact mechanism that the deformation of the device causes the change of internal heat flow distribution since the components will be properly separated. In addition, a simpler double-sided <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">thjc</sub> definition method that directly takes the average value of the case temperature on both sides as the case temperature to calculate the thermal resistance is developed, and the equivalence of the two methods are discussed based on the theoretical analysis and experiment.

Junction temperature estimation approach based on TSEPs in multichip IGBT modules

Junction temperature estimation approach based on TSEPs in multichip IGBT modules

Research on performance parameter degradation of high voltage and high power IGBT module in power cycling test

In Power cycling test, for low-voltage and low-power modules, it is generally considered that the saturation voltage drop VCE(sat) reaches 105% of the initial value or the thermal resistance Rth reaches 120% of the initial value as the basis for judging the failure of the IGBT module. However, since the high-voltage and high-power IGBT modules are connected in parallel with multiple chips, there are differences in the aging speed of the chips, and the degradation of individual chips has little influence on the parameters of the entire module, so the failure judgment standard may not be applicable. In order to obtain the degradation of the characteristic parameters of the high-voltage and high-power IGBT module in the power cycle test, this paper selects the 6500V/600A IGBT module as the research object, adopts the experimental method of constant junction temperature fluctuation, and tests the module parameters after every cycle 20,000 times until the module fails. Three failure modes were found through the test: GE failure, CE failure, GE and CE failure. And the degradation law of the parameters of the high-voltage and high-power IGBT module during the power cycling test was obtained.

Thermal Mitigation and Optimization Via Multitier Bond Wire Layout for IGBT Modules Considering Multicellular Electro-Thermal Effect

The stitch wire configuration is widely adopted for large-area IGBT chips. However, an inhomogeneous wire current density introduces uneven self-heating and nonuniform chip heating, which exacerbates the chip thermal stress. In this article, a multicellular electro-thermal model considering the stitch-bonding wires is derived to optimize the wire layout parameters. Furthermore, the current density alleviation of wire bonds is investigated to be the most sensitive and effective method to comprehensively mitigate the thermal nonequilibrium and local overheating. Consequently, an improved multitier layout is proposed to further achieve thermal stress suppression without any additional components and advanced materials. Finally, a triple-tier-bonded IGBT module with optimal design parameters is fabricated to validate the thermal mitigation performance. The prototype experimental results demonstrate that the modeling error is less than 3.0%. The multitier layout decreases the current density by 57.6%, hence, the maximum and average chip temperature are reduced by 21.8% and 12.4%, respectively.

A Fault Detection Method for Partial Chip Failure in Multichip IGBT Modules Based on Turn-Off Delay Time

Multichip IGBT module has been widely used in high-power converters. Detecting the status of the IGBT chip is a cost-effective approach to improving the reliability of power devices. This article proposes a novel method based on turn-off delay time to detect chip fault in multichip IGBT modules. First, the effect of chip failure on the turn-off process is analyzed, which causes a decrease in turn-off delay time. Then, a detection method of chip failure based on turn-off delay is proposed, which is validated by experimental results. Furthermore, the effects of chip failure on turn-off delay time in different working conditions are investigated through effective experimental results. The tested results show that the proposed method not only has high linearity and sensitivity to chip failure, but can also eliminate the influence of working environments on detection. The proposed method can be used to monitor the health status of multichip modules and is of great significance for enhancing operation reliability.

Comparison of junction temperature variations of IGBT modules under DC and PWM power cycling test conditions

Comparison of junction temperature variations of IGBT modules under DC and PWM power cycling test conditions

Effect of TIM Deterioration on Monitoring of IGBT Module Thermal Resistance and Its Compensation Strategy

Condition monitoring is a cost-effective means to reduce the unscheduled maintenance cost of insulated gate bipolar transistor (IGBT) modules. The junction to case thermal resistance <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R_{\mathrm {thjc}}$ </tex-math></inline-formula> is considered as a critical health indicator of IGBT module solder layer. However, thermal interface materials’ (TIMs) deterioration will not only reduce the heat dissipation performance but also affects the accuracy of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R_{\mathrm {thjc}}$ </tex-math></inline-formula> monitoring of IGBT modules. This article investigates the effect of thermal grease deterioration on <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R_{\mathrm {thjc}}$ </tex-math></inline-formula> monitoring of IGBT module. First, it is found that the thermal grease deterioration will lead to the decrease of monitored <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R_{\mathrm {thjc}}$ </tex-math></inline-formula> of IGBT module under the same health status of IGBT solder layer, despite that the thermal resistance of TIM increasing as deterioration of the TIM takes place. That is, the same monitored increment ratio of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R_{\mathrm {thjc}}$ </tex-math></inline-formula> caused by the solder fatigue may correspond to different health status of the IGBT module, which cannot accurately reflect its actual health status. Then, a compensation strategy for thermal resistance monitoring based on the TIM aging rate is proposed, which uses the established mapping relationship to decouple the negative coupling part of TIM degradation. The compensated thermal resistance can better reflect the actual health status of the IGBT module and approximately eliminate the negative impact. Finally, the feasibility of the proposed compensation strategy is verified by finite element model (FEM) analysis and experiments.

Study on the Effect of Spoiler Columns on the Heat Dissipation Performance of S-Type Runner Water-Cooling Plates

To solve the problem of low heat dissipation efficiency for the conventional S-type runner water-cooling plate of the fan converter IGBT module, two new water-cooling plates were designed with rectangular and elliptical column structures in the S-shaped runner of the water-cooling plate. The heat dissipation performance, the fluidity of cooling water, and pressure drop of different spoiler column structures were compared using Fluent software for the simulation and experiment. The comparative results show, compared with the water-cooling plate without a spoiler column in the flow channel of the control group, that the spoiler column structure in the flow channel significantly improved the heat dissipation performance of the water-cooling plate. When the inlet velocity of the water-cooling plate was 2 m/s, the highest temperature inside the water-cooling plate with a rectangular spoiler column structure was 12.25 °C, lower than the control water-cooling plate. The highest temperature inside the water-cooled plate with an elliptical structure was 12.40 °C, lower than the control water-cooled plate. The obstructive effect of the elliptical spoiler column structure on water flow was smaller than in the rectangular spoiler column structure. The fluidity of the cooling water inside the elliptical spoiler column structure water-cooling plate was better. When the inlet velocity of the water-cooling plate was 2 m/s, the cooling water flowing through the former was 282 L more than the latter in half an hour. Compared to the pressure drop, we found that in the design group, the pressure drop of the water-cooled plate with a rectangular spoiler column structure was 40,988.3 Pa. The pressure drop of the water-cooled plate with an elliptical spoiler column structure was 25,576.6 Pa. The difference between the two was 15,411.7 Pa, which proves that the energy loss inside the latter is smaller. To further explore the relationship between the heat dissipation and energy consumption of the two types of water-cooled plates, the comprehensive evaluation index η was calculated, ηb = 26.2, ηc = 31.6; therefore, ηb was significantly smaller than ηc. The overall performance of the water-cooled plate with an elliptical spoiler column structure was superior.

Study on warpage of the AlSiC substrate in reflow soldering process of the IGBT module

Using the pre-warped substrate to pack IGBT modules can increase the contact area between the substrate and the radiator after the reflow soldering. There are many factors affecting the shape of the substrate’s back after soldering, and determining the effect of each factor by experiments would cost significantly. In this paper, a FEA model of the IGBT module’s reflow soldering process is established by ANSYS to predict the back surface of the pre-warped AlSiC substrate after soldering. Initially, in order to improve the accuracy of the FEA model, the material properties of AlSiC were determined at different temperatures. Subsequently, based on the result of DSC, the solder’s phase transition was simulated in the model. The calculated results showed that the proposed FEA model could predict the shape feature of the AlSiC pre-warped substrate’s back surface after the reflow soldering, and the prediction error of substrate’s residual warpage was 46.05%. The model provides a reliable reference for the design of pre-warped substrate in IGBT module, reducing the test cost and shortening the design period substantially.

Monitoring Initial Solder Layer Degradation in a Multichip IGBT Module via Combined TSEPs

With the development of high power converters, the safe operation of large IGBT modules with parallel chips is of increasing importance. In a multichip module, uneven solder layer degradation translates into higher thermal resistance for some of the chips, leading to junction temperature differences between them. However, the specific meaning of a virtual junction temperature extracted from any external electric characteristic parameter of the module is not yet clear. This paper studies the physical meanings of the temperatures estimated by the threshold voltage and the Miller platform duration as well as the quasi turn- off delay time. Experimental results show that the temperature estimated from the threshold voltage is close to the highest temperature of all the chips, while that estimated from the Miller platform duration or quasi turn-off delay time is close to the average chip temperature. Making use of the difference between the two, this paper proposes a new method to monitor the initial solder layer degradation in the multichip IGBT module. Such a method using combined temperature sensitive electric parameters (TSEPs) is verified for different levels of degradation.

Direct on Chip Thermal Measurement in IGBT Modules Using FBG Technology—Sensing Head Interfacing

This paper assesses the suitability of the use of Fiber Bragg Grating Sensors for effective in-situ sensing of the IGBT junction temperature. To this end, the optical sensor is installed on the chip surface in a commercial IGBT module, enabling direct reading of its junction temperature. Two sensor interfacing configurations are evaluated by means of Finite Element simulations and experiments on a purpose designed laboratory test system. Experiments show the feasibility on the use of FBG sensing technology for reliable and effective real-time measurement of the junction temperature in a wide operating envelope of the tested IGBT device.

Simulation-Assisted Design of a Power Stack for Improving Static Current Sharing Among Three IGBT Modules Connected in Parallel

In this study, cosimulation with Q3D and Simplorer were adopted to design a single-phase power stack with equal output current on three paralleled IGBT modules in high power application, therefore, the derating of total current will be reduced, which can improve the current utilization and power density of power stack. The performance of the designed stack was verified using a double-pulse test (DPT). The circuit used in the DPT regarded the power stack output current as static current, which is a critical index to evaluate current sharing. The static current sharing among the IGBT modules was mainly dependent on the stray inductance of the DC busbar, IGBT modules, and phase output bar (POB), which is used to connect the IGBT modules to load, in parallel paths of the power stack. Cosimulation was performed to determine the stray inductance of the IGBT modules, DC busbar and POB, and a constant-current-slope method was used to verify the inductance. Subsequently, design the shapes of DC busbar and POB for attaining maximum ratio of imbalanced current (MRIC) of the three IGBT modules is within 3% under 200% (2400A) rated current. The cosimulation results indicated that the MRIC of the current paths in power stack were 0.8%. Finally, three IGBT modules and a gate driver were used to construct power stack with 1000V DC link. The experimental results obtained by DPT indicated that the MRIC was 0.9% under 200% rated current, demonstrating the effectiveness of the proposed stray inductance design method.

Growth Behavior and Reliability of Interfacial Imc for Sn58bi/Cu and Sn58bi-Aln/Cu Solder Joints Applied in Igbt Modules

Growth Behavior and Reliability of Interfacial Imc for Sn58bi/Cu and Sn58bi-Aln/Cu Solder Joints Applied in Igbt Modules

Vibration energy recovery system of vehicle suspension based on ultrasonic sensor

The current design of vibration energy recovery system for vehicle suspension does not analyze the vibration of the vehicle under different road conditions, resulting in the system's low energy recovery ratio, low recovery efficiency, and low energy utilization. Therefore, in this paper, the vibration energy recovery system of vehicle suspension based on ultrasonic sensors is proposed. The ultrasonic sensor is used to obtain the vibration information of the vehicle, and the vibration of the vehicle on the smooth and uneven roads is analyzed according to the obtained information. According to the analysis results, the design of the vibration energy recovery system for vehicle suspension is completed through four parts: the IGBT module, the control system, the direct thrust controller, and the energy management controller. The experimental results show that the system designed by the proposed method has a large energy recovery ratio, high recovery efficiency and high energy utilization rate.

Modelling of Wind Turbine Operation for Enhanced Power Electronics Reliability

Enhancing power electronics (PE) converter reliability is crucial for ensuring a reliable operation of current and future operating Wind Turbines (WTs). Achieving high reliability of variable speed WT PE systems requires careful consideration of their operation, and particularly their thermal cycling. This paper presents a methodology for evaluating and reconsidering operational strategies of WTs with relation to the thermal loading and lifetime consumption of the converter. The methodology is applied to compare control strategies for the WT generator and evaluate their impact on the converter reliability by observation of the thermal cycles and by calculating the resultant lifetime consumption of those stress cycles. The thermal stress on both the Machine Side Converter (MSC) and the Grid Side Converter (GSC) is examined and compared. It is shown that the least reliable of the three evaluated control strategies is the one that tracks the power curve below rated speed most closely. This paper suggests that dynamic transients associated with the WT control largely influence the IGBT module wear-out and their modelling needs to be prioritized for lifetime studies. These dynamic transients are captured by the improved model whose value is confirmed for the comparisons in the case study of the paper.