Comparison of Thermal and Stress Analysis Results for a High Voltage Module Using FEA and a Quick Parametric Analysis Tool

Author(s):  
L. M. Boteler ◽  
S. M. Miner

A low order fast running parametric analysis tool, ParaPower, was used to arrive at the design for a novel high voltage module. The low order model used a 3D nodal network to calculate device temperatures and thermal stresses. The model assumed heat flux generated near the top surface of each device which is then conducted through the packaging structure and removed by convection. The temperature distribution is used to calculate thermal stresses throughout the package. This co-design modeling tool, developed for rectilinear geometries, allowed a rapid evaluation of the package temperatures and CTE induced stresses throughout the design space. However, once the final design configuration was determined a detailed finite element analysis was performed to validate the design. This paper compares the results obtained using ParaPower to the FEA, demonstrating the usefulness of the parametric analysis tool. Results for both temperature and CTE induced stress are compared. Two different stress models are evaluated. One based on the more traditional planar module design, which assumes a substantial substrate or heat spreader on which the module is assembled. The other model is less restrictive, eliminating the requirement for a substrate. The FEA modeling was performed using SolidWorks beginning with a thermal analysis followed by a stress analysis based on the temperature solution. Both the values and the trends of the temperatures and stresses were evaluated. The temperature results agreed to within 3.2°C. The trends and sign of the stresses were correctly predicted, but the magnitudes were not. One of the significant advantages of ParaPower is the speed of the computation. The run time for the parametric analysis was roughly two orders of magnitude faster than the FEA. This made it possible to build the model and complete the parametric analysis of roughly 500 runs in less than a day.

Author(s):  
L. M. Boteler ◽  
S. M. Miner

Abstract Co-design and co-engineering have the potential to improve the design of electronics packaging significantly. A co-designed approach moves away from the sequential approach of an electrical layout followed by a mechanical module design, and then the addition of a heat sink. Replacing it with an approach that addresses the electrical, thermal, and mechanical design simultaneously during the initial design. The goal is to evaluate the design space quickly, considering both the thermal and mechanical stress aspects together. ParaPower is a low order fast running parametric analysis tool, developed by the Army Research Laboratory (ARL), that allows rapid evaluation of package temperatures and coefficient of thermal expansion (CTE) induced stresses throughout the design space. The model uses a 3D nodal network to calculate device temperatures and thermal stresses. In order to rapidly evaluate the design space both the thermal and stress models must be reduced order and provide reasonable results on coarse grids. In the case of the stress model, the goal is a low order relationship between the temperatures and the CTE induced stresses. This paper compares three different low order models for stress. The first uses a more traditional planar module design. This assumes a substantial substrate or heat spreader as the base for the module assembly. The second model is less restrictive, eliminating the requirement for a substrate. The third model also eliminates the substrate requirement, but also allows for in-plane distribution of the stresses. The first two models do not account for the in-plane distribution. Two geometries are considered, a standard power module with a substantial substrate and a stacked novel module with no clear substrate layer. Results for both geometries and the three stress models are compared to finite element analysis (FEA) using SolidWorks, beginning with a thermal analysis followed by a stress analysis based on the temperature solution. All three models run roughly two orders of magnitude faster than the FEA and they correctly predict the trends in the CTE induced stresses.


1997 ◽  
Vol 473 ◽  
Author(s):  
S. Lee ◽  
J. C. Bravman ◽  
P. A. Flinn ◽  
T. N. Marffib

ABSTRACTThermal stresses in pure Al lines passivated with a baseline 1000Å oxide and additional passivations of 0.5μm oxide, 1μm polymer, or 0.5μm, 1μm, or 2μ nitride were analyzed. Results from finite element analysis and X-ray measurements were compared, and samples were examined in a high voltage SEM for stress voids. For unvoided samples, calculated and measured results showed good correlation, while results for the voided samples showed little correlation due to stress relaxation through voiding. Initial in-situ electromigration test results showed that electromigration voids can occur at stress void sites.


Author(s):  
L. M. Boteler ◽  
S. M. Miner

This work presents an easy to use approach to quickly estimate the device temperatures and thermal stresses in a generic high power module. A low order model was developed in MATLAB using a combination of numerical-analytical approach and a 3D nodal resistor network to calculate device temperatures and thermal stresses. The model assumes a heat flux generated at the top of each device which is dissipated through the packaging structure and removed by convection. The temperature distribution is used to calculate thermal stresses throughout the package. This method eliminates computer aided drawings (CAD) in favor of numerical parameters that can be easily and quickly varied over a wide range. The resistor network solves quickly in MATLAB, enabling fast, iterative thermal analyses and design through parametric studies of the chip dimensions, number of chips, chip layout, material types, cooling solutions, etc. The model is adaptable to any number of devices and board layers. The MATLAB model reduced the computational time by 97% compared to an equivalent SOLIDWORKS finite element analysis (FEA) model and that does not include the time required to generate the CAD model and verify mesh convergence and mesh independence. Temperatures from the network model were within 5°C and stresses were within 30% of the values obtained from the FEA model. The ability to quickly assess the thermal and stress effects of a wide variety of power module design parameters during the initial design process, without the complexity of a full FEA analysis, with reasonable results can significantly improve the final module.


Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1262
Author(s):  
Alessandro Mingotti ◽  
Federica Costa ◽  
Lorenzo Peretto ◽  
Roberto Tinarelli ◽  
Paolo Mazza

Stray capacitances (SCs) are a serious issue in high-voltage (HV) applications. Their presence can alter the circuit or the operation of a device, resulting in wrong or even disastrous consequences. To this purpose, in this work, we describe the modeling of SCs in HV capacitive dividers. Such modeling does not rely on finite element analysis or complicated geometries; instead, it starts from an equivalent circuit of a conventional measurement setup described by the standard IEC 61869-11. Once the equivalent model including the SCs is found, closed expressions of the SCs are derived starting from the ratio error definition. Afterwards, they are validated in a simulation environment by implementing various circuit configurations. The results demonstrate the expressions applicability and effectiveness; hence, thanks to their simplicity, they can be implemented by system operators, researchers, and manufacturers avoiding the use of complicated methods and technologies.


2021 ◽  
Vol 6 (5) ◽  
pp. 62
Author(s):  
John Morris ◽  
Mark Robinson ◽  
Roberto Palacin

The ‘short’ neutral section is a feature of alternating current (AC) railway overhead line electrification that is often unreliable and a source of train delays. However hardly any dynamic analysis of its behaviour has been undertaken. This paper briefly describes the work undertaken investigating the possibility of modelling the behaviour using a novel approach. The potential for thus improving the performance of short neutral sections is evaluated, with particular reference to the UK situation. The analysis fundamentally used dynamic simulation of the pantograph and overhead contact line (OCL) interface, implemented using a proprietary finite element analysis tool. The neutral section model was constructed using physical characteristics and laboratory tests data, and was included in a validated pantograph/OCL simulation model. Simulation output of the neutral section behaviour has been validated satisfactorily against real line test data. Using this method the sensitivity of the neutral section performance in relation to particular parameters of its construction was examined. A limited number of parameter adjustments were studied, seeking potential improvements. One such improvement identified involved the additional inclusion of a lever arm at the trailing end of the neutral section. A novel application of pantograph/OCL dynamic simulation to modelling neutral section behaviour has been shown to be useful in assessing the modification of neutral section parameters.


2011 ◽  
Vol 55-57 ◽  
pp. 664-669
Author(s):  
Jin Ning Nie ◽  
Hui Wang ◽  
De Feng Xie

According to the situation that the dual-friction drums on the new type towing machine lack stress analysis when designed, the safety is difficult to test and verify. The pull of wire rope in various positions was derived and calculated, so both compressive stress and tangent friction force generated by the pull of wire rope were calculated. The result made by ANSYS software demonstrates the safety of the left drum which suffers from larger loads, structure improvement measures are put forward for the drum.


Author(s):  
Zhao Wen-jie ◽  
Wan Cheng-an ◽  
Gao Yi-fei ◽  
Zhang Guo-shuai ◽  
Zheng Yan ◽  
...  

2007 ◽  
Vol 23 ◽  
pp. 229-232
Author(s):  
Liliana Sandu ◽  
Nicolae Faur ◽  
Cristina Bortun ◽  
Sorin Porojan

Several studies evaluated the removable partial dentures by the finite element analysis, but none of them evaluated thermal stresses. The purpose of the study was to explore the influence of thermal oral changes induced by hot/cold liquids and food on the circumferential cast clasps of removable partial dentures. A 3-dimensional finite element method was used to explore the temperature distribution, thermal stress and the influence of thermal changes on stresses and displacements of circumferential clasps during functions. Thermal variations induce stresses in dental clasps, high temperatures having a more aggressive effect than lower one. Cold liquids and food induce high stresses in the retentive clasp arms while hot ones in the occlusal rests of the clasps and for the back action clasp also in the minor connector. The study suggests the importance of consFigureidering thermal variations for stress analyses of the cast clasps.


Author(s):  
Jaan Taagepera ◽  
Marty Clift ◽  
D. Mike DeHart ◽  
Keneth Marden

Three vessel modifications requiring heat treatment were analyzed prior to and during a planned turnaround at a refinery. One was a thick nozzle that required weld build up. This nozzle had been in hydrogen service and required bake-out to reduce the potential for cracking during the weld build up. Finite element analysis was used to study the thermal stresses involved in the bake-out. Another heat treatment studied was a PWHT of a nozzle replacement. The heat treatment band and temperature were varied with location in order to minimize cost and reduction in remaining strength of the vessel. Again, FEA was used to provide insight into the thermal stress profiles during heat treatment. The fmal heat treatment study was for inserting a new nozzle in a 1-1/4Cr-1/2Mo reactor. While this material would ordinarily require PWHT, the alteration was proposed to be installed without PWHT. Though accepted by the Jurisdiction, this nozzle installation was ultimately cancelled.


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