查看更多>>摘要：This paper presents a new equivalent model based on the Arrhenius law in MATLAB/Simulink environment that can be exploited to evaluate the aging of Li-ion batteries. In this work, we show the simulation results obtained using this model. In addition, an automated test bench for multiple Li-ion battery cell characterization and accelerated aging will be presented together with early measurement results for validating the model.
查看更多>>摘要：This paper presents a comparison on cycling strategies conducted on an experimental study on an NMC lithium-ion battery. The investigation focused on examining the capacity degradation on batteries subjected to two cycling protocols, conducted at an ambient temperature of 0 degrees C and stress factors that depend on actual capacity instead of nominal capacity. The capacity losses were evaluated post-cycling, revealing a degradation of 28.63 % and 25.5 % for cells subjected to Protocol 1, whereas cells cycled under Protocol 2 exhibited lower capacity losses of 21.58 % and 20.73 %.This paper also presents the impact of the discharging current and the depth of discharge on capacity utilization to support the development of optimized cycling protocols for practical applications.
查看更多>>摘要：The automotive lighting industry continues to experience significant growth as it embraces new trends focused on higher performance and smarter functionalities. Any new products in automotive must undergo severe accelerated tests in order to ensure its reliability under the various conditions that it may be confronted with during its lifetime. Due to the coefficient of thermal expansion mismatch between the LED package and the PCB substrate, the solder joint fatigue failure was revealed to be one of the major failure modes during accelerated thermal cycling. The present work focuses on analyzing three LEDs (2-pads, 3-pads and 4-pads) configurations subject to thermal cycling test. First, the damage in the solder joints during tests is observed with dye penetration at different stages of cycling. During the tests, monitoring of the variation of Delta VF was made to follow the performance evolution of LED as a function of cycles. The dye penetration observations were analyzed to follow the evolution of the damage. On the 3 configurations of LEDs (2-pads, 3-pads and 4-pads) a model predicting the damage as function of the Delta VF was defined and used to establish a damage law. The second part is focusing on a thermomechanical modeling of the strains on the solder SAC305 joint occurring during thermal cycles for the 3 configurations of LEDs mounted on the type of IMS PCB. Finally, a fatigue analysis is addressed based on the 3 configurations of LEDs on the time to failure in the thermal cycle test. A comparison between three configurations is made and a correlation with test results is performed to evaluate the accuracy of the prediction.
查看更多>>摘要：This work proposes a physics-based analytical model for p-GaN gate high electron mobility transistors (HEMTs), developed through a self-consistent solution of the Schro<spacing diaeresis>dinger-Poisson equations. The model explicitly accounts for voltage distribution across the device, focusing on voltage drops across the metal/p-GaN Schottky junction and the AlGaN barrier layer. A comprehensive analysis is conducted to evaluate the impact of several factors on the electrical characteristics of p-GaN gate HEMTs. The investigated factors include the net polarization charge density at the AlGaN/GaN interface, out-diffused Mg acceptor density in the AlGaN barrier, and depletion charge density in the unintentionally doped GaN (UID-GaN) buffer layer. Furthermore, a unified expression for the twodimensional electron gas (2DEG) charge density is derived, which is valid across all operation regions. On this basis, expressions for gate capacitance and drain current are developed. The model's credibility is validated by the agreement between modeled and measured C-V and I-V characteristics across three p-GaN gate HEMT samples.
查看更多>>摘要：The increasing complexity of automotive and industrial electronic control units makes traditional finite element analysis impractical for comprehensive design optimization, particularly when addressing thermomechanical reliability. To tackle this issue, a novel approach is introduced that dramatically reduces computational effort while preserving accuracy. The key innovation lies in utilizing a modular system of reduced-order models, which provides a more efficient way to simulate and optimize complex systems. This paper presents projection-based techniques specifically designed to effectively capture the nonlinear material behavior of solder balls, a critical component in electronic assemblies. Employing the Discrete Empirical Interpolation Method enables the representation of all solder balls within an assembly using a single, generalized reduced-order model that captures the highly nonlinear, viscoplastic behavior. This approach reduces the number of elements, leading to significantly faster simulations. Despite the reduction in computational effort, the accuracy of the simulations is maintained, ensuring reliable predictions of the thermomechanical behavior of the solder balls under different loadings. The paper demonstrates the advantages of this method, showing that it can be applied to assemblies with multiple solder balls, offering substantial reductions in the number of elements without compromising accuracy. The results indicate that the proposed approach has great potential for the design process for electronic control units, allowing for more efficient thermomechanical design optimization. Further research will focus on extending the method to handle larger models and investigating its performance for more complex applications.
查看更多>>摘要：As a basic component, multilayer ceramic capacitors (MLCCs) have been widely used in many engineering fields. Failure caused by printed circuit board flex deserves special attention throughout the entire lifecycle of MLCCs. In this failure pattern, the failure probabilities vary across different types of MLCCs. The initial damage location and the direction of cracking propagation display distinct characteristics. This paper presents the MLCC equivalent model by using homogenization theory in finite element method (FEM), and simulates the flex failure of different types of MLCCs. Three-point bending experiments are conducted to validate the FEM results, revealing the underlying cause of flex cracking. The failure pattern inferred by FEM aligns well with the experiment result, with the maximum error of only 7.56 %, demonstrating the equivalent model's effectiveness. Furthermore, we conduct a sensitivity analysis of geometric parameters, including the length-width ratio, terminal electrode width, stacking height, and solder joint height. Our study reveals the underlying mechanism of MLCC flex failure and identifies the key design factors influencing MLCC reliability. These findings provide valuable insights into the design, application, and enhancement of MLCC reliability.
查看更多>>摘要：In this work, a Finite Element (FE) thermal model is presented to further understand the mechanism of surge current-induced failure of press-pack devices. The model is set up with the results of electrical measurements and high-framerate video acquisition taken during diode tests to identify the surge current at which the failure occurs. The tests were carried out with an ad hoc bench specifically designed to have surge currents with different energies to be dissipated in the diode under test using the Integral Resonant Sliding Mode Control (IRSMC) technique.
Belguith, M.Eloued, S.Kadi, M.Slama, J. Ben Hadj...
1.1-1.6页
查看更多>>摘要：GaN's advantages over conventional semiconductors make it an excellent candidate for deployment in the transportation area. This work aims to develop a simple, one-sided DC/DC GaN-based buck converter for manufacturing and prove its feasibility through multiphysics optimization of the chosen topology. To enhance the design, the Ansys "Q3D tool" is employed to estimate parasitic elements, which are subsequently incorporated into an electrical model in the waveform viewer software "LTspice" to evaluate their impact on the switching node signal "Vsw" of the half bridge structure. Next, we will examine the overshoots and ringings by comparing the measured and simulated converter's Vsw and the output signals. We have implemented robust thermal management in this work. Additionally, this study provides an analysis of current density in the layout and heat distribution in the converter circuit. We will present more precise measurement results that align with the simulation in the primary outcomes, showcasing the effectiveness of the converter layout optimization topology.
查看更多>>摘要：In this article, we investigate the Row Hammering (RH) failure with different n-type doping profiles based on 3D TCAD simulation. We propose a simulation structure called de-electrode structure (DS). By comparing the storage node (SN) capacitance voltage variations in the normal structure and the DS, we obtain the trend of charge change induced by electron migration (EM) and capacitive crosstalk (CC) respectively. The simulation result reveals that the mechanisms responsible for RH failure exhibit distinct contributions across different failure modes. CC is the main mechanism of the one-failure induced by passing word line (PWL), while EM and CC synergistically contribute to the zero-failure induced by PWL. According to the charge calculation results, we find that as the bit line (BL) junction depth DBL increases, EM is continuously enhanced, while CC is suppressed. Therefore, we adjust the physical environment of DRAM cell through the PWL work function (WF) improvement and fluorine (F) implantation. This adjustment makes CC the suppression of is greater than the enhancement of EM. This optimization scheme improves the limitation of DBL increase for RH failure suppression, which has important significance for RH failure suppression research.
查看更多>>摘要：We investigate the degradation induced by an OFF state stress condition in normally-on (NON) MIS-HEMTs for power applications. The state of the devices was tracked by considering the shift in the threshold voltage value over time during the stress and the following recovery phase by means of a custom setup. During the transition between stress and recovery, we observed an immediate partial recovery of the VTH (70 %) that occurs in <10 mu s, while the remaining VTH is recovered in about 100 s. With a dedicated analysis, we managed to investigate this ultra-fast recovery transient for the first time, and we observed that the recombination of electrons from 2DEG with ionized donors is responsible for this dynamic.
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Elsevier