scholarly journals The Sensitivity of an Electro-Thermal Photovoltaic DC–DC Converter Model to the Temperature Dependence of the Electrical Variables for Reliability Analyses

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2865 ◽  
Author(s):  
Wieland Van De Sande ◽  
Simon Ravyts ◽  
Omid Alavi ◽  
Philippe Nivelle ◽  
Johan Driesen ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Thermal Model ◽  
Computation Time ◽  
Capital Expenditures ◽  
Plastic Energy ◽  
Main Research ◽  
Die Attach ◽  
Bond Wire ◽  
Energy Dissipated ◽  
Method Model

The operational expenditures of solar energy are gaining attention because of the continuous decrease of the capital expenditures. This creates a demand for more reliable systems to further decrease the costs. Increased reliability is often ensured by iterative use of design for reliability. The number of iterations that can take place strongly depends on the computational efficiency of this methodology. The main research objective is to quantify the influence of the temperature dependence of the electrical variables used in the electro-thermal model on the reliability and the computation time. The influence on the reliability is evaluated by using a 2-D finite elements method model of the MOSFET and calculating the plastic energy dissipation density in the die-attach and the bond wire. The trade-off between computation time of the electro-thermal model in PLECS (4.3, Plexim, Zurich, Switzerland) and generated plastic energy accuracy obtained in COMSOL (5.3, COMSOL Inc., Burlington, MA, USA) is reported when excluding a certain temperature dependence. The results indicate that the temperature dependence of the input and output capacitors causes no change in the plastic energy dissipated in the MOSFET but does introduce the largest increase in computation time. However, not including the temperature dependence of the MOSFET itself generates the largest difference in plastic energy of 10% as the losses in the die are underestimated.

Simulating the Effect of Rigid Frameworks on the Mechanical Properties of Transient Liquid Phase Sintered (TLPS) Alloys

2021 ◽  
Vol 2021 (HiTEC) ◽  
pp. 000089-000093
Author(s):  
Gilad Nave ◽  
Patrick McCluskey
Keyword(s):  
Liquid Phase ◽  
Effective Properties ◽  
Mechanical Strain ◽  
Transient Liquid Phase ◽  
Hazardous Substances ◽  
Automotive Electronics ◽  
Plastic Energy ◽  
Brittle Behavior ◽  
Die Attach ◽  
Transmission Electron

Abstract The need for power electronic devices and materials that can operate in harsh environments, together with the Restriction of Hazardous Substances (RoHS) legislation, has driven industry and researchers to develop new attach materials. Transient Liquid Phase Sintered (TLPS) joints are strong candidates to replace the current die attach materials due to their superior mechanical, thermal, and electrical properties. Despite these qualities, current TLPS systems may exhibit stiff and brittle behavior that can lead to die or attach fracture under large thermomechanical strains during wide temperature range cycling, or under mechanical stress from shock and vibration loading, such as is experienced in automotive electronics. This paper presents an approach for reducing thermal and mechanical strain levels by incorporating Transmission Electron Microscopy (TEM) Cu grids as a reinforcement to the attach material. The grids serve as ductile reinforcement capable of absorbing elastic and plastic energy, and as a barrier for crack propagations through the relative brittle TLPS material. Homogenization calculations were used to evaluate the effective properties of the TLPS, followed by numerical analysis that shows the effect of the grids on the die attach structure, and the mechanical integrity of the design.

scholarly journals Thermo-Mechanical Stress Comparison of a GaN and SiC MOSFET for Photovoltaic Applications

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5900
Author(s):  
Wieland Van De Sande ◽  
Omid Alavi ◽  
Philippe Nivelle ◽  
Jan D’Haen ◽  
Michaël Daenen
Keyword(s):  
Mechanical Stress ◽  
Urban Environments ◽  
Great Promise ◽  
Design For Reliability ◽  
Plastic Energy ◽  
Die Attach ◽  
Photovoltaic Applications ◽  
Bond Wires ◽  
Reliable Design ◽  
Mission Profile

Integrating photovoltaic applications within urban environments creates the need for more compact and efficient power electronics that can guarantee long lifetimes. The upcoming wide-bandgap semiconductor devices show great promise in providing the first two properties, but their packaging requires further testing in order to optimize their reliability. This paper demonstrates one iteration of the design for reliability methodology used in order to compare the generated thermo-mechanical stress in the die attach and the bond wires of a GaN and SiC MOSFET. An electro-thermal model of a photovoltaic string inverter is used in order to translate a cloudy and a clear one-hour mission profile from Arizona into a junction losses profile. Subsequently, the finite element method models of both devices are constructed through reverse engineering in order to analyze the plastic energy. The results show that the plastic energy in the die attach caused by a cloudy mission-profile is much higher than that caused by a clear mission-profile. The GaN MOSFET, in spite of its reduced losses, endures around 5 times more plastic energy dissipation density in its die attach than the SiC MOSFET while the reverse is true for the bond wires. Potential design adaptations for both devices have been suggested to initiate a new iteration in the design for reliability methodology, which will ultimately lead to a more reliable design.

scholarly journals Inverse Thermal Identification of a Thermally Instrumented Induction Machine Using a Lumped-Parameter Thermal Model

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 37 ◽  
Author(s):  
Pieter Nguyen Phuc ◽  
Hendrik Vansompel ◽  
Dimitar Bozalakov ◽  
Kurt Stockman ◽  
Guillaume Crevecoeur
Keyword(s):  
Motor Control ◽  
Real Time ◽  
Induction Motor ◽  
Condition Monitoring ◽  
Thermal Model ◽  
Computation Time ◽  
Absolute Error ◽  
Thermal Parameter ◽  
Maximum Absolute Error ◽  
Lumped Parameter

Accurate temperature estimation inside an electrical motor is key for condition monitoring, fault detection, and enhanced end-of-life duration. Additionally, thermal information can benefit motor control to improve operational performance. Lumped-parameter thermal networks (LPTNs) for electrical machines are both flexible and cost-effective in computation time, which makes them attractive for use in real-time condition monitoring and integration in motor control. However, the accuracy of these thermal networks heavily depends on the accuracy of its system parameters, some of which are difficult to calculate analytically or even empirically and need to be determined experimentally. In this paper, a methodology for the thermal condition monitoring of long-duration transient and steady-state temperatures in an induction motor is presented. To achieve this goal, a computationally efficient second-order LPTN for a 5.5 kW squirrel-cage induction motor is proposed to apprehend the dominant heat paths. A fully thermally instrumented induction motor has been prepared to collect spatial and temporal temperature information. Using the experimental stator and rotor temperature data collected at different motor operating speeds and torques, the key thermal parameter values in the LPTN are identified by means of an inverse methodology that aligns the simulated temperatures of the stator windings and rotor with the corresponding measured temperatures. Validation results show that the absolute average thermal modelling error does not exceed 1.45 °C with maximum absolute error of 2.10 °C when the motor operates at fixed speed and torque. During intermittent motor-loading operation, a mean (maximum) stator temperature error of 0.38 °C (0.92 °C) was achieved and mean (maximum) rotor errors of 2.11 °C (3.40 °C). These results show the validity of the proposed thermal model but also its ability to predict in real time the temperature variations in stator and rotor for condition monitoring and motor control.

Research in Model Testing Pier-Foundation Hysteretic Property in Passenger Dedicated Line

2010 ◽  
Vol 37-38 ◽  
pp. 949-952
Author(s):  
Ming Bo Ding ◽  
Xing Chong Chen
Keyword(s):  
Cyclic Loading ◽  
Failure Mechanism ◽  
Constitutive Relation ◽  
Model Testing ◽  
Static Method ◽  
Test Model ◽  
Plastic Energy ◽  
Hysteretic Property ◽  
Testing Method ◽  
Energy Dissipated

The hysteretic and skeleton curves of load-displacement relation in pier top were got through the model-testing method of pile-soil interaction. The test model of pier was analyzed through static method-pushover. The complexity of subsoil property and constitutive relation of subsoil under reversal cyclic loading was considered. The model characteristics of energy dissipated, hysteretic property, ductility, failure mechanism and plastic energy of the pier under the horizontal reversal cyclic loading were researched.

Curvature Measurements of Tri-Material Structures Under Thermal Excursion

1991 ◽  
Vol 226 ◽  
Author(s):  
Guo-Quan Lu ◽  
Boris Mogilevsky ◽  
Tapan K. Gupta
Keyword(s):  
Thermal Expansion ◽  
Elastic Modulus ◽  
Temperature Dependence ◽  
The Other ◽  
Thermal Expansion Mismatch ◽  
Ceramic Substrates ◽  
Die Attach ◽  
Curvature Measurements ◽  
Thermal Excursion

AbstractThe bending curvatures of tri-material plates have been measured using in situ laser reflection technique at temperatures ranging from 20°C to 160°C. The tri-material structures are formed by attaching silicon wafers to ceramic substrates with die-attach adhesives from solder-like (elastic modulus ≈ 24 GPa) to gel-like (elastic modulus ≈ 0.003 GPa) characteristics. The temperature dependence of curvature as a result of the thermal expansion mismatch is measured. The structure bonded by the gel-like adhesive has substantially lower, about a factor of ten less, bending than the structures attached by the other two types of adhesives. We found good agreements between the measurements and the theoretical derivations by Suhir[1] for the bending curvature of finite tri-material assembly.

Micro-Indentation of Aluminum Processed by Equal Channel Angular Extrusion

2004 ◽  
Vol 19 (4) ◽  
pp. 1243-1248 ◽  
Author(s):  
Fuqian Yang ◽  
Lingling Peng ◽  
Kenji Okazaki
Keyword(s):  
Applied Load ◽  
Surface Deformation ◽  
Equal Channel Angular Extrusion ◽  
Pure Aluminum ◽  
Local Deformation ◽  
Near Surface ◽  
Plastic Energy ◽  
History Of ◽  
Energy Dissipated ◽  
Micro Indentation

The near-surface deformation of equal-channel angular extruded (ECAE) pure aluminum was investigated using the micro-indentation technique. Compared with fully annealed Al samples, there is a distinguishable difference in the indentation deformation. The unloading slope of the ECAE deformed Al after a short unloading period was found to be less than that of the annealed samples due to plastic recovery. Work hardening was observed, which depended on the history of local deformation. A new relationship between the plastic energy dissipated in the indentation and the applied load was derived, which is supported by the experimental results.

Effect of cold rolling on the indentation deformation of AA6061 aluminum alloy

2005 ◽  
Vol 20 (5) ◽  
pp. 1172-1179 ◽  
Author(s):  
Fuqian Yang ◽  
Wenwen Du ◽  
Kenji Okazaki
Keyword(s):  
Plastic Deformation ◽  
Indentation Load ◽  
Dislocation Dynamics ◽  
Al Alloy ◽  
Deformation History ◽  
Plastic Energy ◽  
Average Dislocation Density ◽  
Deformation State ◽  
Energy Dissipated ◽  
Indentation Strain

The indentation behavior of cold-rolled AA6061 Al alloy was investigated. Following the approach suggested by Tabor, indentation stress–indentation strain curves were constructed and analyzed. The indentation stress required to create the same indentation strain increases with an increase in the reduction of thickness, suggesting a strong effect of plastic deformation history on the deformation behavior of materials. Through the dislocation dynamics, the evolution of the dislocations underneath the indentation was correlated with the plastic deformation history and the indentation load. The plastic energy dissipated in indentation was then calculated and found to be proportional to the 3/2 power of the indentation load and the 3/4 power of the average dislocation density underneath the indentation. The ratio of the dissipated plastic energy to the total energy in the indentation was demonstrated to be a function of the deformation state in materials, independent of the indentation load.

Microindentation of titanium: Dependence of plastic energy on the indentation depth and time-dependent plastic deformation

2008 ◽  
Vol 23 (4) ◽  
pp. 1068-1075 ◽  
Author(s):  
Rong Chen ◽  
Fuqian Yang ◽  
M. Ashraf Imam ◽  
C.R. Feng ◽  
Peter Pao
Keyword(s):  
Plastic Deformation ◽  
Indentation Depth ◽  
Pure Titanium ◽  
Indentation Load ◽  
Time Dependent ◽  
Indentation Hardness ◽  
Commercially Pure Titanium ◽  
Plastic Energy ◽  
Commercially Pure ◽  
Energy Dissipated

The cavity model and the dislocation mechanics were used to analyze the plastic energy dissipated in an indentation deformation. The plastic energy dissipated in an indentation cycle was proportional to the cube of the residual indentation depth. The experimental results supported the analysis for the indentation of commercially pure titanium by a Vickers indenter. Slip bands around the indentation were observed, suggesting that the indentation deformation was controlled by dislocation motion. The indentation hardness decreased with the indentation load, showing the indentation size effect. The ratio of the total energy to the plastic energy was found to be proportional to the ratio of the maximum indentation depth to the residual indentation depth. The effects of holding time were examined on the time-dependent plastic deformation of the commercially pure titanium at ambient temperature.

scholarly journals Analytical Thermal Model of a Generic Multi-Layer Spacerless 3D Package

2011 ◽  
Author(s):  
Nuwan Rodrigo ◽  
Saeed Ghalambor ◽  
Abdolhossein Haji-Sheikh ◽  
Dereje Agonafer
Keyword(s):  
Thermal Model ◽  
Three Dimensional ◽  
Conduction Model ◽  
Die Attach ◽  
Die Stacking ◽  
Solder Balls ◽  
Steady State Heat ◽  
The Cost ◽  
Analytical Thermal Model ◽  
3D Package

The need for more functions in a single device has led to die stacking architecture. Although the number of die increases further to accommodate package functionality, the overall package dimensions have not increased; they have stayed the same or decreased (roughly 1.4mm). If this trend continues, in order to keep the same package height, alternate stacking structures need to be investigated. One such opportunity is the spacerless die stacking architecture. Using dummy silicon spacers add to the cost of a package and do not increase the memory or functionality, although they serve as enablers for wire bonding of same size die. Spacerless architecture reduces the package height by eliminating spacers or dummy die. This allows for an increased number of active die to be stacked directly on one another without changing the overall package height, or in some cases reducing the package height. Previous work [1] has been done to develop a steady-state heat conduction model in a two-layer body. This analytical model will be extended to the current multi-layered generic spacerless three dimensional packages (3DP) enabling the computation of temperature for uniform or non-uniform powered die. The computation will account for the contact resistance created by the die attach and the solder balls. Finally validation of this analytically developed model will be carried out with a numerical model.

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