Faculty Advisors: Dr. Kenneth Goodson and Dr. Debbie Senesky
Description: Recent trends towards smaller electronics packaging and high power devices result in increasing power densities which require aggressive thermal management including special consideration for reliability, size, noise and power consumption issues. This project examines cooling strategies for high power electronics devices using chip level-embedded cooling solutions with micro-channels directly fabricated into Si or SiC substrates compatible with fabrication of power electronic devices thus eliminating any thermal interface and decreasing overall thermal resistance. We consider both single and two phase performance of these systems, characterizing thermal resistance, temperature uniformity, hot spot mitigation, and coefficient of performance (CoP) as a function of working fluid composition and operating condition as well as micro-channel geometry. The goal is to dissipate extreme heat loads with low thermal resistance (e.g. > 800 W/cm2 over 1 cm2 with less than 50 K superheat). Tight integration of advanced microfluidic cooling solutions with heat generating devices offers potential for dramatic improvements in the thermal management of power electronics with attendant gains in performance and efficiency. Specific tasks include but not limited to basic calculation and measurement of temperature and pressure drop in microheat exchangers.
3D integrated power electronics and microfluidic cooling for future electric aircrafts.
Faculty Advisors:Dr. Robert Pilawa, Dr. Ken Goodson
Description: This project will develop novel 3D integrated power converters and advanced thermal management solutions for future electric aircrafts, enabling radically new aircraft designs with up to 40% fuel savings. REU students will participate in the fabrication (soldering, 3D printing, assembly) and testing (electrical wiring, measurements, data analysis) of high power inverters and advanced heatsink designs.
Active Jumping Droplet Vapor Chambers for High Heat Flux Cooling
Description: Coalescence induced droplet jumping has the potential to act as an ideal liquid supply mechanism in vapor chamber devices integrated with electronics components. This REU project will involve the thermal testing of active jumping droplet vapor chambers integrated with gallium nitride transistors to achieve cooling heat fluxes approaching 100 W/cm2. The student will be required to learn and use thermal characterization tools such as high speed imaging, thermography, and LabVIEW electrical control to characterize the integrated device performance. Surface nanostructure fabrication will be learned and utilized prior to testing while thermal and error analysis will be learned and utilized after testing
Additive Manufacturing for Power Electronics
Faculty Advisor:Dr. Juan Balda
Description: Additive manufacturing for power electronics is gathering momentum due to the availability of PLA-based conductive, magnetic and insulating materials . Most current applications have been devoted to the use of plastics to produce different housings for power converters. This REU project will evaluate the potential for using 3D printing techniques for prototyping conducting vias, heat sinks, and other components.
Carbon Nanotube Thermal Routers
Faculty AdvisorsDr. Joseph Lyding
Description: Carbon nanotube (CNT) thermal routing structures will be fabricated from composite CNT fibers. This project involves CNT growth, fiber spinning and processing fibers for enhanced thermal conductivity. CNTs have high intrinsic thermal conductivity that is much higher than that exhibited by CNT composites. A key goal of this project is to recover as much of this lost thermal conductivity as possible.
Current and Temperature Sensors capable of operating at High Temperatures
Description: Our group is developing sensors which can remotely detect electrical current at high temperatures through the generated magnetic field. In high power density power supplies, the ambient temperature is expected to exceed the operating temperature of current materials which are used to make these kinds of sensors called Hall Sensors. We are looking at developing new materials and structures which can operate at these temperatures and in fact are more stable throughout a much larger temperature range. These new materials based on wide bandgap semiconductors of Gallium and Nitrogen (GaN) and Silicon and Carbon (SiC) are in their technological infancy compared to very mature semiconductor technology based on silicon (Si).
In our lab we study this material and new structures starting from the crystal growth by molecular beam epitaxy (MBE) and through bulk electrical and optical characterization, device fabrication and testing, and ultimately into systems integration. Currently, we are testing devices up to about 350°C and starting to get an understanding of the useful lifetime of these devices when operated at these high temperatures even up to 500°C. REU students will help with either (1) growth, (2) fabrication, or (3) testing of these devices with specific emphasis on high temperature and lifetime behavior. They will also learn about semiconductor and Hall Effect physics, engineering Hall devices, and develop skills using fabrication and test equipment.
Development of Nanofluids for Microchannel Heat Transfer
Faculty Advisor:Dr. Sonia Smith
Description: In this project, REU students will test nanofluids with multiple particle diameters for coolant in microchannels with varying widths. The students will then build a candidate device to prototype and test heat removal using these novel fluids. The experimental analysis will be tested against a predictive computational Analysis using this of the same candidate device.
Diagnosis of Power Electronic Switches
Faculty Advisor:Dr. Charles Kim
Description: This REU Summer Program provides students with opportunity to learn and do research on electro-thermal sensing and monitoring for control and design optimization of wide bandgap high electron mobility transistor (HEMT)-based power electronic systems such as power converters, inverters, and motor drives. Optical and magnetic sensing methods for temperature and current are coordinated to characterize the spatial distribution of temperature and current in a power electronics system. Students who are not available during summer but are interested in continuous year-round learning and collaboration with other students can participate, alternatively, in a global and inter-collegiate team project by joining the VIP (Vertically Integrated Project) team called DOPES (Diagnosis of Power Electronics Switches) at Howard University.
Electro-thermal & Mechanical Stress Interactions in EV/HEV Power Modules
Faculty Advisors:Dr. David Huitink, Dr. Simon Ang, and Dr. Michael Glover
Description: Our group is leading the development of a rapid mechanical reliability benchmarking methodology for assessing electronic components in high temperature applications like electric vehicle drive systems. The REU student will work with packaging engineers to build and test prototype modules, and correlate results with finite element models for determining field reliability. Participation in subsequent publications is expected.
Electro-Thermal Systems Modeling and Validation
Faculty Advisors:Dr. Andrew Alleyne and Dr. Robert Pilawa
Description: This project will create models of complex power systems such as those found in modern aircraft. This includes electrical and thermal elements. It will also validate these models from data taken off a laboratory test platform. The student will perform both the modeling and the experiments to validate the models.
High efficiency, compact power electronics for electric vehicles
Faculty Advisor:Dr. Robert Pilawa
Description: In this project, we are developing extreme light-weight, low-volume power electronics used in various electric vehicles, ranging from automobiles to electric aircraft. The project has a strong hands-on prototyping and experimental measurement component, and will include soldering, printed-circuit board layout and design, measurement automation, and development of mechanical enclosures and heatsink.
Integrated Physical and Control System Design for Electro-Thermal Systems
Faculty Advisor:Dr. James Allison
Description: Conventional design strategies for actively controlled engineering systems use a sequential approach: physical system elements are designed first, followed by control system design. It is now understood that coupling exists between physical and control system design decisions, i.e., physical design influences what choices are best for control system design, and vice versa. Conventional sequential strategies cannot fully capitalize on this design coupling, whereas emerging integrated, or co-design, methods can leverage synergistic relationships to improve performance. This project involves the development and study of new co-design methods specifically for electro-thermal systems, with the objective of making possible new levels of power density while ensuring reliable operation. The case study focuses on the integration of sensor placement, observer and control design, and possibly other design elements. Models that account for electro-thermal interactions will be used along with design optimization techniques. Helpful background for undergraduate students interested in applying for this project include: dynamic systems/state-space models, control system design, numerical methods (specifically optimization and solution of differential equations), and experience with electrical or thermal system modeling and design.
Investigate alternative optimization methods for PowerSynth
Faculty Advisors:Dr. James Allison, Dr, Alan Mantooth, and Dr. Sonia Smith
Description: The current optimization algorithm used with PowerSynth, a genetic algorithm (GA), is a powerful algorithm for solving very difficult problems. They are considered a global optimization algorithm, and while cannot guarantee a global optimal solution, improve the probability of finding one. GAs, however, require a very large number of function evaluations. This is fine when function evaluations are fast and when the number of design optimization variables is small. Improving model fidelity and design flexibility, however, may render the current optimization strategy impractical. In this task we will systematically investigate alternative optimization strategies that may help improve numerical efficiency by capitalizing on problem structure.
Low Temperature Co-fired Ceramic Fabrication for Power Electronic Modules
Faculty Advisor:Dr. Simon Ang
Description: This project involves the fabrication of low temperature co-fired ceramic (LTCC) substrates for use in power module applications. Students will learn the basic design and fabrication techniques associated with LTCC technology and will fabricate LTCC samples that will support the project goal of leveraging LTCC technology to build power modules with higher power density and novel electrical/thermal pathways. Students will also shadow and assist other project researchers as they evaluate fabricated samples.
Multi-Physics Model for High Frequency Air-Core Electrical Machines
Faculty Advisors: Dr. Kiruba Haran, Dr. Andrew Alleyne, Dr. Phil Krein, and Dr. Robert Pilawa
Description: Assist in the development and validation of analytical models for a novel electrical machine architecture where the traditional electromagnetic path dominated by ferromagnetic steel is mostly eliminated. The effort will include computing electromagnetic fields, losses, forces, temperatures, and key performance metrics. Validation will be through detailed finite element based numerical models and bench tests.
Next Generation of Testbeds for Electric Vehicle Powertrains
Faculty Advisors:Dr. Juan Balda
Description: The main objective of this REU project is to develop a manual for Testbed 2 that will allow a user to design an experiment for her/his prototype under test. To this end, the REU student will perform the following activities: (a) Become familiar with the operation of the testbed and its associated software package as well as EPA driving schedules and main powertrain topologies employed in hybrid and electric vehicles. (b) Select and model a vehicle operating under certain conditions (e.g., rainy day, head wind of 10 mph and a gradient of 10 degrees) to be included as a case study in the testbed manual. (c) Design of the experiments that will be carried out in the testbed for inclusion in the manual. (d) Perform the experiments designed in (c) above. (e) Write the first draft of the testbed manual.
Raman Thermometry of Graphene Thermal Switches
Faculty Advisors:Dr. Eric Pop
Description: In this project, the REU student will learn how to use Raman thermometry to measure the temperature of nano- and micro-scale objects, and apply it to assist with thermal measurements of certain graphene devices. Graphene is an atomically thin lattice of carbon atoms (subject of the 2010 Nobel prize in Physics) with thermal conductivity comparable to that of diamond, but with less than 1 nm thickness. Here we are using graphene for thermal routing and switching in very tight spaces. The graphene thermal switches could be used for heat management in mobile electronics (e.g. cell phones) or high-power electronics. The REU student will learn about the physics of Raman scattering, how to calibrate and use Raman spectroscopy as a thermal instrument, and how to work with graphene devices. The REU student will also have ample opportunities for collaborations with Illinois, Howard, and Arkansas researchers, as well as with researchers working on thermal simulation aspects. (For example, some of the experimental findings will be used to directly inform computer models of the structures being measured.) The project will also offer opportunities to publish results in top-tier journals and conferences.
Reliability and Aging of GaN-based Sensors and Electronics within Extreme Environments
Faculty Advisors:Dr. Debbie Senesky, Dr. Kenneth Goodson, Dr. Andrew Alleyne, Dr. Robert Pilawa, Dr. Greg Salamo, Dr. Simon Ang
Description: In order to tap the full operation potential of wide bandgap semiconductors (e.g., gallium nitride and silicon carbide) at high temperatures (above 250°C), it is crucial to understand the material and electrical degradation mechanisms at elevated temperatures. Unfortunately, metal contacts are the first to break down in air at temperatures much below the theoretical limit of the semiconductor. The goal of this project is to perform long-term reliability study of various GaN devices at high temperatures. The thermo-chemical and thermo-electrical behavior of these devices will be fundamentally understood through this work. Results from this project will support the vision of electronics that are able to operate at temperatures beyond 600°C and enhance the reliability of GaN- and SiC-based electronics. This project will leverage semiconductor clean room facilities at Stanford University and thermo-electrical characterization systems within the Extreme Environment Microsystems Laboratory (XLab)
Thermal energy routing materials
Faculty Advisors:Dr. Paul Braun, Dr. Nenad Miljkovic, and Dr. Robert Pilawa
Description: Thermal energy routing is a problem impacting a diverse set of fields. Currently, there is no good way to route thermal energy in a solid-state device, in distinct contrast from the way electrical energy can be routed. This project will focus on the synthesis of organic and inorganic materials which can be externally switched between low and high thermal conductivity states, and the integration of these materials into devices
Thermal switching for three-dimensional control of heat flow
Faculty Advisors: Dr. William King, Dr. Nenad Miljkovic
Description: The basic building block of electronic systems is the transistor, which uses a switch to modulate electrical current between ON and OFF states. Electrical switches allow engineers to exert powerful control over the operation of electronic systems. Today, thermal switches exist only in the research laboratory. Our group at the University of Illinois is working to develop a thermal switch that can be used to control heat flow in thermal systems. We have built prototype thermal switches at the level of electronics packages, about 10 mm in size. The goal of this project is to integrate these thermal switches with power electronics and to thereby demonstrate the potential of these devices. Interested students will do experiments and make calculations of heat flow, working in the research labs of mechanical engineers and electrical engineers. The research demonstration will target a relevant application in automotive thermal management. The results of this project will be presented to other thermal systems researchers and to practicing engineers in industry.
Thermoelectric Sensing and Energy Harvesting
Faculty Advisor:Dr. Eric Pop
Description: In this project, the REU student will learn about thermoelectric energy harvesters, and how to incorporate them in practical devices. Thermoelectric energy harvesters rely on the Seebeck effect, which states that a temperature gradient leads to a voltage gradient in a materials (like semiconductors) or material junctions. We will study the behavior, use, and integration of thermoelectrics as temperature sensors and as energy harvesters. If time permits, we will seek to build a practical energy harvester from off-the-shelf thermoelectrics, with the goal to generate sufficient power to power an LED or to (slowly) charge a wearable device, like a Fitbit.
Validating Power Modules Synthesized by PowerSynth
Faculty Advisors:Dr. Alan Manstooth, Dr. James Allison , Dr. Sonia Smith
Description: Our group is leading the development of a design automation tool capable of synthesizing power module layouts in a fraction of the time it takes an individual to create such a layout. Further, this tool is guaranteed to produce layouts that perform better and have higher power density than hand-designed layouts. The REU student will work with packaging engineers to build prototype modules created by PowerSynth. He/she will use the tool, generate layouts, fabricate them and test them in the laboratory in order to validate the tool’s predicted performance against fabricated hardware. Participation in subsequent publications is expected.