scholarly journals Electric-Drive Vehicle Power Electronics Thermal Management: Current Status, Challenges, and Future Directions

2021 ◽  
Author(s):  
Gilberto Moreno ◽  
Sreekant Narumanchi ◽  
Xuhui Feng ◽  
Paul Anschel ◽  
Steve Myers ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
Power Electronics ◽  
Thermal Management ◽  
Power Density ◽  
Thermal Performance ◽  
Electric Drive ◽  
Thermal Analyses ◽  
Heat Fluxes ◽  
Current Status ◽  
Dielectric Fluid

Abstract Effective thermal management of traction-drive power electronics is critical to the advancement of electric-drive vehicles and is necessary for increasing power density and improving reliability. Replacing traditional silicon devices with more efficient, higher temperature, higher voltage, and higher frequency wide-bandgap (WBG) devices will enable increased power density but will result in higher device heat fluxes. Compact packaging of high-temperature WBG devices near low-temperature-rated components creates thermal management challenges that need to be addressed for future power-dense systems. This paper summarizes the thermal performance of on-road automotive power electronics thermal management systems and provides thermal performance and pumping-power metrics for select vehicles. Thermal analyses reveal that the package/conduction resistance dominates the total thermal resistance (for existing automotive systems). We model advanced packaging concepts and compare the results with existing packaging designs to quantify their thermal performance enhancements. Double-side-cooled configurations that do not use thermal interface materials are package concepts predicted to provide a low junction-to-fluid thermal resistance (compared to current packages). Dielectric-fluid-cooled concepts enable a redesign of the package to reduce the package resistance, can be implemented in single- and two-phase cooling approaches, and allow for cooling of passive components (e.g., capacitors) and bus bars.

Lightweight, Cost-Effective Power Modules Using Polymer Baseplates With Integrated Microconvective Cooling

2021 ◽  
Author(s):  
David Earley ◽  
Jordan Mizerak ◽  
Chris May ◽  
Bernard Malouin
Keyword(s):  
Power Electronics ◽  
Thermal Management ◽  
Power Density ◽  
Thermal Power ◽  
Heat Removal ◽  
Cost Effective ◽  
Heat Fluxes ◽  
Cold Plate ◽  
Power Module ◽  
Heat Spreading

Abstract The advent of wide bandgap (WBG) semiconductors, such as silicon carbide (SiC) and gallium nitride (GaN), has enabled power electronics with increasing current densities and switching frequencies. A byproduct of these improved electrical characteristics is an increase in thermal power density. Indeed, the full capability of WBG semiconductors may be underutilized if the thermal management solution cannot keep pace with the device heat generation density. Further, as many power electronics devices are integrated into a power module form factor containing a metal baseplate to allow heat spreading from high heat fluxes generated at semiconductor dies, system integrators are often sensitive to cost and weight considerations in building up systems with traditional power module designs. In this paper, a polymer baseplate with integrated microconvective cooling (PBIMC) is designed and built as a low-weight, cost-effective alternative for metal baseplates on power module devices. Microconvective cooling, featuring optimized single-phase impingement cooling and effluent fluid flow control, provides high power density heat removal from localized heat flux areas in power module packages to obviate the need for a metal heat spreader. Thermal performance of the PBIMC is tested on a thermal test vehicle representative of an IGBT power module to power densities up to 200W/cm2 and compared to an off the shelf minichannel cold plate. The PBIMC achieved equivalent per IGBT case-to-fluid areal thermal resistances of 0.15 K-cm2/W, a 69% decrease compared to the baseline cold plate. Additionally, thermal crosstalk was shown to be reduced by up to 89% when moving from the cold plate to the PBIMC, demonstrating potential advantages in utilizing thermal management techniques that do not feature heat spreading. The prototype-level polymer baseplates showed a > 80% decrease in weight compared to a traditional power module metal baseplate. The study concludes that the PBIMC shows promise as a solution for high current density power electronics in weight sensitive applications, while providing opportunities for cost savings.

Integrated Vapor Chamber Heat Spreader for Power Module Applications

2017 ◽  
Author(s):  
Clayton L. Hose ◽  
Dimeji Ibitayo ◽  
Lauren M. Boteler ◽  
Jens Weyant ◽  
Bradley Richard
Keyword(s):  
Heat Flux ◽  
Thermal Resistance ◽  
Power Electronics ◽  
Coefficient Of Thermal Expansion ◽  
High Heat ◽  
Heat Fluxes ◽  
High Heat Flux ◽  
Vapor Chamber ◽  
Power Module ◽  
Heat Spreader

This work presents a demonstration of a coefficient of thermal expansion (CTE) matched, high heat flux vapor chamber directly integrated onto the backside of a direct bond copper (DBC) substrate to improve heat spreading and reduce thermal resistance of power electronics modules. Typical vapor chambers are designed to operate at heat fluxes > 25 W/cm2 with overall thermal resistances < 0.20 °C/W. Due to the rising demands for increased thermal performance in high power electronics modules, this vapor chamber has been designed as a passive, drop-in replacement for a standard heat spreader. In order to operate with device heat fluxes >500 W/cm2 while maintaining low thermal resistance, a planar vapor chamber is positioned onto the backside of the power substrate, which incorporates a specially designed wick directly beneath the active heat dissipating components to balance liquid return and vapor mass flow. In addition to the high heat flux capability, the vapor chamber is designed to be CTE matched to reduce thermally induced stresses. Modeling results showed effective thermal conductivities of up to 950 W/m-K, which is 5 times better than standard copper-molybdenum (CuMo) heat spreaders. Experimental results show a 43°C reduction in device temperature compared to a standard solid CuMo heat spreader at a heat flux of 520 W/cm2.

Reliability of Bonded Interfaces for Automotive Power Electronics

2013 ◽  
Author(s):  
Douglas DeVoto ◽  
Paul Paret ◽  
Sreekant Narumanchi ◽  
Mark Mihalic
Keyword(s):  
Thermal Resistance ◽  
Power Electronics ◽  
Carbon Fibers ◽  
Thermal Performance ◽  
Coefficient Of Thermal Expansion ◽  
Base Plate ◽  
Acoustic Microscopy ◽  
Thermal Cycles ◽  
Interface Materials ◽  
Sintered Silver

In automotive power electronics packages, conventional thermal interface materials such as greases, gels, and phase change materials pose bottlenecks to heat removal and are also associated with reliability concerns. There is an industry trend towards high thermal performance bonded interfaces. However, due to coefficient of thermal expansion mismatches between materials/layers and resultant thermomechanical stresses, adhesive and cohesive fractures could occur, posing a problem from a reliability standpoint. These defects manifest themselves in increased thermal resistance in the package. The objective of this research is to investigate and improve the thermal performance and reliability of emerging bonded interface materials for power electronics packaging applications. We present results for thermal performance and reliability of bonded interfaces based on thermoplastic (polyamide) adhesive, with embedded near-vertical aligned carbon fibers, as well as sintered silver material. The results for these two materials are compared to conventional lead-based (Sn63Pb37) bonded interfaces. These materials were bonded between 50.8-mm × 50.8-mm cross-sectional footprint silicon nitride substrates and copper base plate samples. Samples of the substrate/base plate bonded assembly underwent thermal cycling from −40°C to 150°C according to Joint Electron Devices Engineering Council standard Number 22-A104D for up to 2,000 cycles. The dwell time of the cycle was 10 minutes and the ramp rate was 5°C/minute. Damage was monitored every 100 cycles by acoustic microscopy as an indicator of an increase in thermal resistance of the interface layer. The acoustic microscopic images of the bonded interfaces after 2,000 thermal cycles showed that thermoplastics with embedded carbon fibers performed quite well with no defects, whereas interface delamination occurred in the case of sintered silver material. Both these materials showed a superior bond quality as compared to the lead-based solder interface even after 1,000 thermal cycles.

Evaporative Thermal Performance of Vapor Chambers Under Nonuniform Heating Conditions

2008 ◽  
Vol 130 (12) ◽  
Author(s):  
Je-Young Chang ◽  
Ravi S. Prasher ◽  
Suzana Prstic ◽  
P. Cheng ◽  
H. B. Ma
Keyword(s):  
Heat Flux ◽  
Thermal Resistance ◽  
Thermal Performance ◽  
Hot Spots ◽  
Hot Spot ◽  
Heat Fluxes ◽  
Experimental Results ◽  
Nonuniform Heating ◽  
Test Results ◽  
Uniform Heating

This paper reports the test results of vapor chambers using copper post heaters and silicon die heaters. Experiments were conducted to understand the effects of nonuniform heating conditions (hot spots) on the evaporative thermal performance of vapor chambers. In contrast to the copper post heater, which provides ideal heating, a silicon chip package was developed to replicate more realistic heat source boundary conditions of microprocessors. The vapor chambers were tested for hot spot heat fluxes as high as 746 W/cm2. The experimental results show that evaporator thermal resistance is not sensitive to nonuniform heat conditions, i.e., it is the same as in the uniform heating case. In addition, a model was developed to predict the effective thickness of a sintered-wick layer saturated with water at the evaporator. The model assumes that the pore sizes in the sintered particle wick layer are distributed nonuniformly. With an increase of heat flux, liquid in the larger size pores are dried out first, followed by drying of smaller size pores. Statistical analysis of the pore size distribution is used to calculate the fraction of the pores that remain saturated with liquid at a given heat flux condition. The model successfully predicts the experimental results of evaporative thermal resistance of vapor chambers for both uniform and nonuniform heat fluxes.

Enhanced Miniature Loop Heat Pipe Cooling System for High Power Density Electronics

2012 ◽  
Vol 4 (2) ◽  
Author(s):  
J. H. Choi ◽  
B. H. Sung ◽  
J. H. Yoo ◽  
C. J. Kim ◽  
D.-A. Borca-Tasciuc
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Power Density ◽  
Thermal Performance ◽  
High Power ◽  
Design Stage ◽  
Working Fluid ◽  
High Power Density ◽  
Graphic Processing Units ◽  
Maximum Heat

The implementation of high power density, multicore central and graphic processing units (CPUs and GPUs) coupled with higher clock rates of the high-end computing hardware requires enhanced cooling technologies able to attend high heat fluxes while meeting strict design constrains associated with system volume and weight. Miniature loop heat pipes (mLHP) emerge as one of the technologies best suited to meet all these demands. Nonetheless, operational problems, such as instable behavior during startup on evaporator side, have stunted the advent of commercialization. This paper investigates experimentally two types of mLHP systems designed for workstation CPUs employing disk shaped and rectangular evaporators, respectively. Since there is a strong demand for miniaturization in commercial applications, emphasis was also placed on physical size during the design stage of the new systems. One of the mLHP system investigated here is demonstrated to have an increased thermal performance at a reduced system weight. Specifically, it is shown that the system can reach a maximum heat transfer rate of 170 W with an overall thermal resistance of 0.12 K/W. The corresponding heat flux is 18.9 W/cm2, approximately 30% higher than that of larger size commercial systems. The studies carried out here also suggest that decreasing the thermal resistance between the heat source and the working fluid and maximizing the area for heat transfer are keys for obtaining an enhanced thermal performance.

Thermal Analysis of High Efficiency High Speed Drives

2019 ◽  
Author(s):  
Yasmin Khakpour ◽  
Weilun Warren Chen ◽  
Parikshith Channegowda ◽  
Matthew R. Pearson ◽  
Yongduk Lee ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Thermal Resistance ◽  
Power Electronics ◽  
Thermal Management ◽  
High Speed ◽  
High Efficiency ◽  
Management Strategies ◽  
Substantial Reduction ◽  
Operating Conditions ◽  
Heat Conducting

Abstract The thermal management of the PCB based power electronics is a key element to ensure safe operating conditions and to meet lifetime, reliability and safety requirements. This is challenging for applications above 1 kW because the substrate material used in a PCB such as FR-4 has very low heat conducting properties. Hence, there is a limit on how much loss can be dissipated from the board and for that reason this approach has only been adopted in the industry for very low power applications. With the proposed multilevel topology, WBG devices, and innovative thermal management strategies it is possible to expand the PCB based power electronics approach to power ratings between 1kW and 10 kW. For instance, an improvement in the thermal resistance of the PCB can be obtained by soldering a discrete WBG device with a TO-263 package directly on a PCB with about one inch square copper area around the device which will act as a heat spreader. Then, a further substantial reduction in the thermal resistance of a PCB is possible by the application of electrical vias. In principle each via is a copper sleeve through the board or through a part of the board. Where, instead of using its electrical function, a via can also be used as a thermal conductor. In this work, the thermal analysis of the PCB and the effect of number of vias as well as the effect of filling the vias with a thermally conductive material has been studied. The design has been optimized for the number of vias and the modeling results have been verified with experimental tests.

Effect of Flow Guide Integration on the Thermal Performance of High Performance Liquid Cooled Immersion Server Modules

2015 ◽  
Author(s):  
Joshua Gess ◽  
Tyler Dreher ◽  
Sushil Bhavnani ◽  
Wayne Johnson
Keyword(s):  
Pressure Drop ◽  
Surface Temperature ◽  
Thermal Performance ◽  
Power Dissipation ◽  
High Performance ◽  
High Heat ◽  
Heat Fluxes ◽  
Dielectric Fluid ◽  
Computing Device ◽  
Flow Guide

Liquid immersion cooling technology, currently in its nascence as a commercially available solution for data center installations, is growing in popularity as the power density of next-gen electronics necessitates a matriculation to thermal management techniques capable of handling incredibly high heat fluxes reliably and efficiently. The use of boiling and single-phase convective solutions using dielectric fluids can result in dramatic reductions in chip temperatures, thus increasing reliability. The latter method is growing in popularity faster than the former but, as both of these approaches gain acceptance, packaging engineers will require insight into how coolant is distributed throughout the enclosure for either solution. More specifically, analytical and experimental techniques will be required to ascertain how thermal performance and system efficiency of more critical elements, such as processor chips, are affected by the auxiliary components, heated or not, that must exist within a computing device. These supplemental components, whether entirely passive or modestly heated, if placed strategically can be integrated in such a way to improve the thermal performance of the system by guiding the coolant through the liquid filled enclosure. To this end, flow guides, which simulate these auxiliary components, have been integrated into a small form factor high performance server module. The relationship between the surface temperature and the power dissipated by the primary heated elements within the device has been explored as well as the pressure drop experienced by the coolant flowing through the enclosure. Power dissipations near 450W have been achieved at a surface temperature of approximately 75°C with the use of flow guides, a near 50W improvement over previous results. Furthermore, this value was attained at a modest pressure drop of 0.71 psi for the dielectric fluid flowing through the cartridge. Slightly over 300W of power dissipation was achieved at an even lower pressure drop of 0.13 psi at a similar operating temperature. Pool boiling results have shown that passive elements can have a significant impact on thermal performance. Reductions of nearly 50W in the maximum power dissipation achieved have been shown when the largest flow guide is integrated. A PIV analytical method is proposed and applied to the current experimental facility to assess the effectiveness of the flow guide design proposed.

Experimental Characterization of Two-Phase Cooling of Power Electronics in Thermosiphon and Forced Convection Modes

2021 ◽  
Vol 143 (3) ◽  
Author(s):  
Fabio Battaglia ◽  
Farah Singer ◽  
David C. Deisenroth ◽  
Michael M. Ohadi
Keyword(s):  
Heat Flux ◽  
Thermal Resistance ◽  
Power Electronics ◽  
Forced Convection ◽  
Heat Removal ◽  
High Heat ◽  
Heat Fluxes ◽  
High Heat Flux ◽  
Two Phase ◽  
Total Thermal Resistance

Abstract In this paper, we present the results of an experimental study involving low thermal resistance cooling of high heat flux power electronics in a forced convection mode, as well as in a thermosiphon (buoyancy-driven) mode. The force-fed manifold microchannel cooling concept was utilized to substantially improve the cooling performance. In our design, the heat sink was integrated with the simulated heat source, through a single solder layer and substrate, thus reducing the total thermal resistance. The system was characterized and tested experimentally in two different configurations: the passive (buoyancy-driven) loop and the forced convection loop. Parametric studies were conducted to examine the role of different controlling parameters. It was demonstrated that the thermosiphon loop can handle heat fluxes in excess of 200 W/cm2 with a cooling thermal resistance of 0.225 (K cm2)/W for the novel cooling concept and moderate fluctuations in temperature. In the forced convection mode, a more uniform temperature distribution was achieved, while the heat removal performance was also substantially enhanced, with a corresponding heat flux capacity of up to 500 W/cm2 and a thermal resistance of 0.125 (K cm2)/W. A detailed characterization leading to these significant results, a comparison between the performance between the two configurations, and a flow visualization in both configurations are discussed in this paper.

Experimental Characterization of a Carbon Fiber Composite Material Heat Sink in Boiling Heat Transfer Using FC-72

2006 ◽  
Author(s):  
Venugopal Gandikota ◽  
Harish Chengalvala ◽  
Amy S. Fleischer ◽  
G. F. Jones
Keyword(s):  
Heat Transfer ◽  
Composite Material ◽  
Carbon Fiber ◽  
Thermal Management ◽  
Thermal Performance ◽  
Heat Sink ◽  
Heat Fluxes ◽  
Two Phase ◽  
Operating Temperatures ◽  
Power Densities

The on-going trend towards increasing device performance while shrinking device size often results in escalating power densities and high operating temperatures. High operating temperatures may lead to reduced reliability and induced thermal stresses. Therefore, it is necessary to employ new and innovative thermal management techniques to maintain a suitable junction temperature at high power densities. For this reason, there is interest in a variety of liquid cooling techniques. This study analyzes a composite material heat sink. The heat sink consists of a very large number of small cross-section fins fabricated from carbon pitch fibers and epoxy. These carbon pitch fibers have a high thermal conductivity along the length of the fin. It is expected that the longer length will result in more heat transfer surface area and a more effective heat sink. This experimental study characterizes the thermal performance of the carbon-fiber heat sink in a two-phase closed loop thermosyphon using FC-72 as the operating fluid. The influence of heat load, thermosyphon fill volume, and condenser operating temperature on the overall thermal performance is examined. The results of this experiment provide significant insight into the possible implementation and benefits of carbon fiber heat sink technology in two-phase flow leading to significant improvements in thermal management strategies for advanced electronics. The carbon fiber heat sink yielded heat transfer coefficients in the range of 1300-1500 W/m2 K for heat fluxes in the range up to 3.2 W/cm2. Resistances in the range of 0.20 K/W – 0.23 K/W were achieved for the same heat fluxes. Condenser temperature and fill ratio did not show a significant effect on any of the results.

Experimental Study on the Double-Sided Air Cooling for Integrated Power Electronics Modules

2005 ◽  
Author(s):  
Ying Feng Pang ◽  
Elaine P. Scott ◽  
Zhenxian Liang ◽  
J. D. van Wyk
Keyword(s):  
Thermal Resistance ◽  
Power Electronics ◽  
Thermal Management ◽  
Heat Sink ◽  
Three Dimensional ◽  
Management Approach ◽  
Air Cooling ◽  
Thermal Tests ◽  
Heat Spreaders ◽  
Embedded Power

The objective of this work is to quantify the advantages of using double-sided cooling as the thermal management approach for the integrated power electronics modules. To study the potential advantage of the Embedded Power packaging method for the double-sided cooling, experiments were conducted. Three different cases were studied. To eliminate the effect of the heat sink on either side of the module, no heat sink was used in all three cases. The thermal tests were conducted such that the integrated power electronics modules were placed in the middle of flowing air in an insulated wind tunnel. Modules without additional top DBC, with additional top DBC, and with additional top DBC as well as heat spreaders on both sides were tested under the same condition. A common parameter, junction-to-ambient thermal resistance, was used to compare the thermal performance of these three cases. Despite the shortcoming of this parameter in describing the three-dimensional heat flow within the integrated power electronics modules, the concept of the thermal resistance is still worthwhile for evaluating various cooling methods for the module. The results show that increasing the top surface area can help in transferring the heat from the heat source to the ambient through the top side of the module. Consequently, the ability to handle higher power loss can also be increased. In summary, the Embedded Power technology provides an opportunity for implementing double-sided cooling as thermal management approach compared to modules with wire-bonded interconnects for the multichips.

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