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Electrical Efficiency

The Research Foundation for State University of New York, on behalf of SUNY Polytechnic Institute

Demonstration of PN-junctions by Implant and Growth techniques for GaN

The State University of New York Polytechnic Institute (SUNY) will develop innovative doping process technologies for gallium nitride (GaN) vertical power devices to realize the potential of GaN-based devices for future high efficiency, high power applications. SUNY's proposed research will focus on ion implantation to enable the creation of localized doping that is necessary for fabricating GaN vertical power devices. Ion implantation is a doping process used in other semiconductor materials such as Si and GaAs but has been difficult to use in GaN due to the limited ability to perform high temperature heat treatments or anneals needed to activate the implanted dopants and repair the damage caused by implantation. The team will develop new annealing techniques to activate magnesium or silicon implanted in GaN to build p-n junctions, the principal building block of modern electronic components like transistors. High temperature anneals will be performed using an innovative gyrotron beam technique (a high-power vacuum tube that generates millimeter-length electromagnetic waves) and an aluminum nitride cap. Central to the team's project is understanding the impact of implantation on the microstructural properties of the GaN material and effects on performance.

Transphorm, Inc.

High-Performance GaN HEMT Modules for Agile Power Electronics

Transphorm is developing transistors with gallium nitride (GaN) semiconductors that could be used to make cost-effective, high-performance power converters for a variety of applications, including electric motor drives which transmit power to a motor. A transistor acts like a switch, controlling the electrical energy that flows around an electrical circuit. Most transistors today use low-cost silicon semiconductors to conduct electrical energy, but silicon transistors don't operate efficiently at high speeds and voltage levels. Transphorm is using GaN as a semiconductor material in its transistors because GaN performs better at higher voltages and frequencies, and it is more energy efficient than straight silicon. However, Transphorm is using inexpensive silicon as a base to help keep costs low. The company is also packaging its transistors with other electrical components that can operate quickly and efficiently at high power levels--increasing the overall efficiency of both the transistor and the entire motor drive.

United Technologies Research Center

Power Conversion Through Novel Current Source Matrix Converter 

United Technologies Research Center will develop a silicon carbide-based, single stage, 15 kW direct AC-to-AC (fixed frequency AC to variable frequency AC) power converter that avoids the need for an intermediate conversion to DC or energy storage circuit elements. The team seeks to build a device that weighs about half as much as available converters while demonstrating scalability for a broad power range (from kW to tens of MW) and achieving conversion efficiencies greater than 99%. If successful, the UTRC team will produce advances that help greatly reduce energy losses in a range of industrial applications. Industrial drives for electric motors alone account for approximately 40% of total U.S. electricity demand and incorporation of highly efficient variable-frequency drives, based on this technology, can reduce energy consumption by 10-30%. For aircraft power systems, electrical actuators built using this technology can enable longer, thinner, and lighter wings that result in 50% reduced fuel consumption and carbon emissions when compared to current commercial aircraft. The project can also open new possibilities for electric locomotives and ship propulsion, thanks to the reduced weight and complexity of the converter.

United Technologies Research Center

Ultra Dense Power Converters for Advanced Electrical Systems

The United Technologies Research Center and its project team will develop an extremely efficient power converter capable of handling kilowatts of electricity at ultra-high power densities. The team will leverage the superior performance of silicon carbide (SiC) or gallium nitride (GaN) devices to achieve its efficiency and power density goals. In the aerospace industry, electrical power distribution can begin to displace pneumatic power distribution using this technology. Efficient power conversion in aircraft will be needed as hydraulic systems, including landing gear systems, are replaced with electric actuation. Electric engine start, electric air-conditioning and cabin pressurization are also key advances in this area. One of the major objectives of the team is to halve converter loss, facilitating a transition from present liquid cooling thermal management to air cooling only. These improvements can help reduce the weight of airline electrical components, critical for the advancement of more electric aircraft. If successful, the team expects that aerospace is a good first adopter of their technology as the industry can more easily accommodate the costs and adoption of new technology better than other industrial applications.

University of Arkansas

Reliable, High Power Density Inverters for Heavy Equipment Applications

The University of Arkansas and its project team will develop a power inverter system for use in the electrification of construction equipment. Heavy equipment providers are increasingly investing in electrification capability to perform work in harsh environments. As with all electrified systems, size, weight and power considerations must be met by these systems. The team's approach is to utilize the advantages of wide bandgap semiconductors not only in the converter elements themselves, but also in the converter’s gate driver as well. This innovation of having the low-voltage circuitry built from the same materials as the power devices enables higher reliability, longer life, and a more compact system packages. Their multi-objective optimization method will provide the best outcome and trade the efficiency and power density goals against circuit complexity, device ratings, thermal management, and reliability constraints. If successful, the team will achieve an improvement of four times the power density and reduce converter cost by 50% compared to today’s technology. The proposed design methods and technological advances can also be applied to many applications such as electric vehicles, smart grid power electronics, and data centers.

University of California, Berkeley

Extreme Efficiency 240 Vac to Load Data Center Power Delivery Topologies and Control

The University of California Berkeley and its project team will develop an extremely efficient AC-to-DC converter based on gallium nitride (GaN) devices for use in datacenters. Datacenters are the backbones of modern information technology and their physical size and power consumption is rapidly growing. Converters for datacenters need to be power dense and efficient to maximize the computing power per unit volume and to reduce operating costs and environmental impact. This project team seeks to develop a prototype device that converts power from a universal grid input (110-240 V at 50-60 Hz) to 48 V DC, the standard for datacenter and telecom supply. The team hopes that this GaN-based converter will enable a complete redesign of the power delivery network for future datacenters; while achieving a three-fold reduction in energy loss and 10 times improvement in power density over traditional conversion circuits. If successful, project developments will greatly reduce the amount of energy lost powering datacenters while significantly improving power capability over current converters.

University of California, Berkeley

IceNet for FireBox

The University of California, Berkeley will develop a new datacenter network topology that will leverage the energy efficiency and bandwidth density through the integration of silicon photonics into micro electro-mechanical system (MEMS) switches. Today's datacenter architectures use server nodes (with processor and memory) connected via a hierarchical network. In order to access a remote memory in these architectures, a processor must access the network to get to a particular server node, gaining access to the local memory of that server. This requires the remote server processor to be awake at all times in order to service the remote request. The processor-to-memory network has many stages and long latency, which results in significant energy waste in processor and memory idling on both sides of the network. The IceNet network is designed to achieve ultra-low latency connectivity between processor nodes and memory, drastically reducing energy wasted during system idling. A key component to the team's design is their LightSpark active laser power-management system. In addition to guiding the laser power where it is needed, the LightSpark module enables both wavelength and laser redundancy, increasing the robustness of the system. In total, the IceNet network will enable dramatic improvements in datacenter system efficiency, allowing for fine-grain power control of processors, links, and memory and storage components.

University of California, Berkeley

Enabling Ultra-Compact, Lightweight, Efficient, and Reliable 6.6 kW On-Board Bi-Directional Electric Vehicle Charger with Advanced Topology and Control

The University of California Berkeley and its project team will develop an on-board electric vehicle charger using a gallium nitride (GaN) based converter to improve power density and conversion efficiency. Conventional power converter topologies which primarily use magnetics (i.e. inductors and transformers) for energy transfer suffer from a tradeoff between efficiency and size. In this project, the team proposes a shift in traditional charger design to develop a bidirectional converter dominated by capacitor-based energy transfer. The team will leverage recent advances in GaN devices and new control techniques to produce a 6.6 kW converter with 15 times the power density and higher efficiency than currently achievable. The bidirectional flow means that the device can act to charge the electric vehicle or operate in a vehicle-to-grid manner to use the vehicle as short term energy storage. If successful, project developments could help reduce the size and complexity of electric vehicle power systems.

University of California, San Diego

LEED: A Lightwave Energy-Efficient Datacenter

The University of California, San Diego will develop a new datacenter network based on photonic technology that can double the energy efficiency of a datacenter. Their LEED project mirrors the development of CPU processors in PCs. Previous limitations in the clock rate of computer processors forced designers to adopt parallel methods of processing information and to incorporate multiple cores within a single chip. The team envisions a similar development within datacenters, where the advent of parallel lightwave networks can act as a bridge to more efficient datacenters. This architecture leverages advanced photonic switching and interconnects in a scalable way. Additionally, the team will add a low-loss optical switch technology that routes the data traffic carried as light waves. They will also add the development of packaged, scalable transmitters and receivers that can be used in the system without the need for energy-consuming optical amplification, while still maintaining the appropriate signal-to-noise ratio. The combination of these technologies can create an easily controllable, energy-efficient architecture to help manage rapidly transitioning data infrastructure to cloud-based services and cloud-based computing hosted in datacenters.

University of California, Santa Barbara

High Efficiency Quantum-Dot Photonic Integrated Circuit Technology Epitaxially Grown on Silicon

The University of California at Santa Barbara will develop a new technology for optical communication links. Optical interconnects transfer data by carrying light through optical fibers, and offer higher bandwidths than copper with higher efficiency and, consequently, reduced heat losses. However, short-reach optical interconnects are not widely used because of their higher costs and larger device footprints. Production costs of these interconnects could be reduced by using silicon-based fabrication technologies, but silicon is not suited for fabricating lasers, a key ingredient. In contrast III-V semiconductors, are well-suited for fabricating highly efficient lasers, but at a high cost. The team plans to combine these components to create III-V lasers, grown on a silicon substrate, harnessing both the low cost of silicon and the superior laser of the III-V semiconductor. However, growing the III-V laser material directly on silicon is difficult due to incompatibilities in their crystal structures. The team aims to overcome this challenge by implementing nanostructures called "quantum dots" as the light producing material and by growing the structure on patterned silicon substrates to help contain potential defects.

University of California, Santa Barbara

Laser-Based Solid State Lighting 

The University of California, Santa Barbara will develop a gallium nitride (GaN) laser-based white light emitter with no efficiency droop at high current densities. The team's solution will address the efficiency and cost limitations of LEDs. Laser diodes do not suffer efficiency droop at high current densities, and this allows for the design of lamps using a single, small, light-emitting chip operating at high current densities. Using a single chip reduces system costs compared with LEDs because the system uses less material per chip, requires fewer chips, and employs simplified optics and a simplified heat-sink. The chip area required for LED technologies will be significantly reduced using laser-based solid state lighting. This technology will also enable highly controllable beams of light that cannot be achieved with LEDs. The goal of the project is to develop a 1,000 lumen laser-based white light emitter with the efficiency of at least 200 lm/W and a cost of $0.25/klm.

University of California, Santa Barbara

Intelligent Reduction of Energy through Photonic Integration for Datacenters (INTREPID)

The University of California, Santa Barbara will develop and demonstrate a technology platform that integrates efficient photonic interfaces directly into chip "packages." The simultaneous design and packaging of photonics with electronics will enable higher bandwidth network switches that are much more energy efficient. Traditional electronic switches toggle connections between wires, each wire providing a different communication channel. Having a limited number of communication channels means that electronic switches can lead to "fat" hierarchical networks, consuming energy each time data has to travel through one switch to another. By developing a platform that directly integrates efficient photonics into first-level chip packages, layers of traditional network hierarchy can be eliminated, reducing the power, latency, and cost of datacenters. Photonic interconnects integrated directly into chip packages can enable switches with a much larger port count than traditional electronic switches. These new, larger switches will connect more servers using fewer levels of required switching. The team estimates that an improvement in the network metrics (either cost or power) will enable a more than linear improvement in the overall transactional efficiency because faster networks and faster endpoint data-rates can be deployed, reducing the total number of computational and storage systems necessary to satisfy user transactions.

University of California, Santa Barbara

Current Aperture Vertical Electron Transistor Device Architectures for Efficient Power Switching

The University of California, Santa Barbara (UCSB) will develop new vertical gallium nitride (GaN) semiconductor technologies that will significantly enhance the performance and reduce the cost of high-power electronics. UCSB will markedly reduce the size of its vertical GaN semiconductor devices compared to today's commercially available, lateral GaN-on-silicon-based devices. Despite their reduced size, UCSB's vertical GaN devices will exhibit improved performance and significantly lower power losses when switching and converting power than lateral GaN devices. UCSB will also simplify fabrication processes to keep costs down.

University of Colorado, Boulder

A High-Voltage, High-Reliability Scalable Architechture for Electric Vehicle Power Electronics 

The University of Colorado Boulder and its project team will develop new composite SiC power converter technology that achieves high power and voltage conversion (250 VDC to 1200 VDC) in a smaller package than ever achieved due largely to improved switching dynamics and reduced need for large passive energy storage components. Also, utilizing higher system voltage in vehicular power systems has been proven to enable vehicle manufacturers to use thinner and lighter wires and improve vehicle powertrain system efficiency. The team seeks to demonstrate the power converter as an on-board, high-power, multifunctional system for both charging electric vehicles and providing power to the motor. The project will lead to experimental demonstration of a 100 kW multifunction electric vehicle power conversion system that includes integrated wired charging and wireless charging functions. If successful, the CU Boulder team will make important progress towards reducing the size, cost, and complexity of power systems associated with electric vehicles.

University of Illinois, Chicago

Universal Battery Supercharger

The University of Illinois at Chicago will develop a new high-power converter circuit architecture for fast charging of electric vehicles (EV). Their wide-bandgap universal battery supercharger (UBS) is designed using a unique AC/DC converter system. Fast-switching silicon carbide (SiC) field-effect transistors (FETs) with integrated gate-drivers are used to achieve the targeted compactness. A novel hybrid-modulation method is used to switch the SiC-FETs to reduce the semiconductor power losses and improve the efficiency. The UBS uses integrated filters, which reduce the electromagnetic noise and system weight. The UBS circuit is reliable because it uses film capacitors instead of electrolytic capacitors that have reduced durability. The reduced weight and size of the UBS can enable both off-board stationary fast charging systems and as a portable add-on system for EV customers who require range enhancement and quick charging in 15 minutes. If successful, project developments will not only help accelerate the development of EV charging infrastructure, but the system will have bidirectional power flow capability enabling vehicle-to-grid dispatching.

University of Maryland

Melt Epitaxy of Carbon: A Silicon-inspired Approach to Next-Generation Electrical Wires

The University of Maryland will develop a new method called "Melt Epitaxy of Carbon" for the production of lightweight, high-capacity carbon wires from carbon nanotubes. Metallic carbon nanotubes are lightweight, high-capacity conductors that exceed the current carrying capacity of metals like copper. The current density of carbon nanotubes is nearly 1,000 times greater than at the electromigration limit of copper. On a weight basis, carbon nanotubes have an additional 6-fold advantage over copper because of their reduced density. Carbon nanotubes can reduce the weight of wires as much as 90% in weight-critical applications such as aircraft. Epitaxy refers to the deposition of a crystalline overlayer on a crystalline substrate, and it is widely used to create materials for semiconductor fabrication. In this process, the team will use a similar method to produce the carbon conductors. Although carbon nanotubes can also be synthesized using chemical vapor deposition, this new method is predicted to deliver improved yield and greater control over the structure and electrical properties of the nanotubes. This method is also more scalable than other methods of nanotube creation and at reduced costs.

University of Missouri

High quality GaN FETs through Transmutation Doping and Low Temperature Processing

The University of Missouri will develop neutron transmutation doping of GaN to fabricate uniform heavily doped n-type GaN wafers. GaN has long been proposed as a superior material for power electronic devices due to the intrinsic material advantages such as greater breakdown voltages and greater stability. Unfortunately, the fabrication of GaN wafers with uniform and high levels of dopants is challenging due to a lack of sufficient control during the existing crystal growth methods. The neutron transmutation doping process, which consists of exposing GaN wafers to neutron radiation to create a stable network of the dopant germanium within the GaN wafer, allows for a greater degree of precision and results in a high level, uniform doping concentrations across the wafer. With this method, repeatable production of high quality GaN substrates may be achieved. Specific innovations in this proposal concern an in-depth study of neutron transmission doping and a characterization of the resulting wafer, including analyzing resistivity, dopant concentration, unwanted impurities, and damage to the GaN lattice.

University of Nebraska, Lincoln

Voltage and Frequency Power Converter Based on Electromagnetic Induction

The University of Nebraska-Lincoln will develop an innovative concept for an electromagnetic induction-based static power converter for AC to AC electrical conversions. Their method will use a new device, the magnetic flux valve, to actively control the magnetic flux of the converter. The voltages induced across the device can be controlled by varying the magnetic fluxes. By synthesizing the induced voltages appropriately, the converter can take an AC input and generate an AC output with controllable amplitude, frequency, and waveform. During this project, the team plans to prove the concept of the magnetic flux valve; prove the concept for variable-frequency and variable voltage AC-AC electrical energy conversion; and conduct a study on the scalability of the magnetic flux valve and electromagnetic power converter concepts. If successful, the technology has the potential to achieve lower cost, higher energy density, and higher efficiency than traditional energy conversion technologies. More efficient conversion technologies for high voltage and high power applications can lead to new innovations in renewable power generation and smart grid applications.

University of Southern California

System Testbed, Evaluation, and Architecture Metrics: STEAM

The University of Southern California (USC) will develop a framework and testbed for evaluating proposed photonic and optical-electronic interconnect technologies, such as those developed under the ARPA-E ENLITENED program. These new approaches will develop novel network topologies enabled by integrated photonics technologies, which use light instead of electricity to transmit information. USC's effort aims to offer an impartial assessment of these emerging datacenter concepts and architectures and their ability to reduce overall power consumption in a meaningful way. The team will focus on developing architecture specifications and models to assess the effects of photonic project components on system performance and efficiency, making it possible to quantify the potential energy reduction in datacenters. Specifically, they will simulate the impact on overall energy efficiency of dramatically different traffic, loading, and architectural configurations and then identify how individual new technologies such as optical components, optical switches, and transceivers, affect efficiency. The team expects that capabilities and facilities influenced by the project will form the basis of a national facility for evaluating new concepts for datacenter operations and the role of photonics in those systems.

University of Wisconsin

WBG-Enabled Current-Source Inverters for Integrated PM Machine Drives

The University of Wisconsin-Madison and its project team will develop new integrated motor drives (IMDs) using current-source inverters (CSIs). Recent advances in both silicon carbide (SiC) and gallium nitride (GaN) wide-bandgap semiconductor devices make these power switches well-suited for the selected CSI topology that the team plans to integrate into high-efficiency electric motors with spinning permanent magnets. The objective is to take advantage of the special performance characteristics of the technology to increase the penetration of variable-speed drives into heating, ventilating, and air conditioning (HVAC) applications. Many of the HVAC installations in the U.S. residential and commercial sectors still use constant-speed motors even though there is a well-recognized potential for major energy savings available by converting them to variable-speed operation. If successful, the new IMDs will be capable of producing significant energy savings in a wide variety of industrial, commercial, and residential applications ranging from air conditioners to pumps and compressors.


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