Search NASA⌕ Search

SEARCH · Search NASA

Results for “Power electronics”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 685 records · Page 38
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Electric Vehicles at Scale (EVs@Scale) Laboratory Consortium Deep-Dive Technical Meetings: High Power Charging (HPC) Summary Report

Electric vehicle (EV) adoption will change the composition of EV charging load to higher-power charging as more medium- (MD) and heavy-duty (HD) applications are electrified, and as all vocations, including light-duty (LD) vehicles, are capable of faster charging. These shifts provide the opportunity for high-power charging (HPC) and facility equipment to evolve and improve efficiency, cost, and space. High-Power Electric Vehicle Charging Hub Integration Platform (eCHIP) project designs and develops a high-power, interoperable charging experimental platform to research, develop, and demonstrate the integration approaches and technology solutions. The project addresses (1) interconnection and management of a grid-tied inverter; (2) development of a DC distribution system that is responsible for system energy management, interoperability, and DC protection; (3) modular DC/DC conversion for vehicle charging; (4) EV charging interface and DC/DC integration; and (5) smart charge control and vehicle-to-edge (vehicle-to-building [V2B], vehicle-to-everything [V2X]) capability. This summary presentation is the first technical progress output of the project. It provides insight for the first deep-dive technical meeting outputs in terms of research presentations and also includes summary of the discussions occurred in the follow-up breakout sessions. The summary presentation covers three technical areas: (1) HPC: State of the art power architectures and the design of the power electronics, (2) Modeling, energy management, and power control in the HPC station, and (3) Next Generation Profiles for high power charging characterization.

ADVANCED PROPULSION SYSTEMS↗
NASA NTRS1995

Program Calculates Power Demands Of Electronic Designs

CURRENT computer program calculates power requirements of electronic designs. For given design, CURRENT reads in applicable parts-list file and file containing current required for each part. Program also calculates power required for circuit at supply potentials of 5.5, 5.0, and 4.5 volts. Written by use of AWK utility for Sun4-series computers running SunOS 4.x and IBM PC-series and compatible computers running MS-DOS. Sun version of program (NPO-19590). PC version of program (NPO-19111).

Cox, Brian↗
DOE OSTI2024

Role of gas composition in weakened nonlinear standing wave excitation and improved plasma radial uniformity in very-high-frequency asymmetric capacitive Ar/CF 4 discharges

Abstract The higher harmonics generated by nonlinear sheath motion would enhance the standing wave effect, and thus lead to center-peaked plasma density profile in very-high-frequency (VHF) capacitive discharges. In this work, a nonlinear transmission line (NTL) model introduced in Zhouet al(2021Plasma Sources Sci. Technol.30125017) has been extended, with radial transport of various particles and nonlinear sheath motion into account, to investigate the effects of CF 4 fraction α on the nonlinear standing wave excitation and plasma radial uniformity in VHF (60 MHz) capacitively coupled Ar/CF 4 plasmas at 3 Pa. The results indicate that for pure Ar discharges (i.e. α = 0%), the nonlinearly excited harmonics with short wavelength significantly enhance the electron power absorption at the radial center, resulting in a pronounced central-high plasma density profile. As α increases, the high-order harmonics are gradually damped due to the increase of resistance, as well as the longer wavelength caused by thicker sheath thickness. Thus, the radial profile of the electron absorbed power density shifts from center-peak to edge-high. Besides, at the radial center, the electron density and Ar + ion density decrease with α , CF 3 + ion density shows an increasing trend, while F − ion density initially rises and then decreases. Moreover, the density profiles of all the species become more uniform at higher CF 4 fraction, due to the suppressed nonlinear standing wave excitation and the longer wavelength of the nonlinear harmonics.

Physics↗
NASA NTRS1993

Chemical Vapor Deposition Of Silicon Carbide

Large single-crystal SiC boules from which wafers of large area cut now being produced commerically. Availability of wafers opens door for development of SiC semiconductor devices. Recently developed chemical vapor deposition (CVD) process produces thin single-crystal SiC films on SiC wafers. Essential step in sequence of steps used to fabricate semiconductor devices. Further development required for specific devices. Some potential high-temperature applications include sensors and control electronics for advanced turbine engines and automobile engines, power electronics for electromechanical actuators for advanced aircraft and for space power systems, and equipment used in drilling of deep wells. High-frequency applications include communication systems, high-speed computers, and microwave power transistors. High-radiation applications include sensors and controls for nuclear reactors.

Powell, J. Anthony↗
DOE OSTI2017

Five Indisputable Facts on Modern Power Systems

This presentation overviews five indisputable facts about modern power systems: Fact one: The grid can handle more renewable generation than previously thought. Fact two: Geographic and resource diversity provide additional reliability to the system. Fact three: Wind and solar forecasting provide significant value. Fact four: Our electric power markets were not originally designed for variable renewables -- but they could be adapted. Fact five: Modern power electronics are creating new sources of essential reliability services.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2021

True Breakdown Voltage and Overvoltage Margin of GaN Power HEMTs in Hard Switching

This work studies the dynamic breakdown voltage (BV) and overvoltage margin of a 650-V-rated commercial GaN power HEMT in hard switching. The dynamic BV measured in the hard switching circuits is over 1.4 kV, being 450 V higher than the static BV measured in the quasi-static I-V sweep. The device can survive at least 1 million hard-switching overvoltage pulses with 1.33 kV peak overvoltage (~95% dynamic BV). Recoverable device parametric shifts are observed after the 1-million pulses, featuring small reductions in threshold voltage and on-resistance. These shifts are different from the ones after the hard-switching pulses without overvoltage and are attributable to the trapping of the holes produced in impact ionization. Furthermore, these results suggest that the BV and overvoltage margin of GaN HEMTs in practical power switching can be significantly underestimated using the static BV. Index Terms— GaN, HEMT, power electronics, hard switching, breakdown voltage, overvoltage, ruggedness, reliability.

42 ENGINEERING↗
DOE OSTI2024

Integrated Traction Drive Thermal Management: Keystone Project 3

The presentation represents a report of accomplishments during FY 2024 and is prepared for 2024 DOE VTO Annual Merit Review. The project goal is identifying pathways enabling high-performance, compact, and reliable integrated electric drives and facilitation of achieving DOE 2025 target of 33 kW/L system power density for an electric traction drive through support of other EDT consortium members in design and development of thermal management systems for their respective integrated drive concepts. Specific objectives are: 1) research and evaluation of motor-integrated power electronics packaging technologies and thermal management approaches; 2) explore novel materials and manufacturing options (3D printing with thermally enhanced polymers or ceramic materials) for key thermal management system components; 3) develop thermal management system and its sub-components to enable integrated electric drive DOE power density targets in collaboration with project partners; 4) support activities of DOE's Electric Drive Technologies (EDT) consortium members, Oak Ridge National Laboratory (ORNL), University of Wisconsin and Georgia Tech research teams in thermal management component design and thermal modeling of their integrated traction drives.

ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2025

Enhancement-Mode GaN Monolithic Bidirectional Switch With Breakdown Voltage Over 3.3 kV

Here, this work demonstrates a GaN enhancement-mode monolithic bidirectional switch (MBDS) with breakdown voltage (BV) higher than 3.3 kV in both polarities. This MBDS is realized on a dual p-GaN gate high electron mobility transistor (HEMT) platform on sapphire substrate. It features a novel dual junction termination extension design for electric field management, which is built on the p-GaN layer in the gate stack and does not require epitaxial regrowth. The GaN MBDS exhibits symmetric on-state characteristics in both directions with a threshold voltage (V th ) of 0.6 V and a low specific on-resistance (R on,sp ) of 5.6 m Ω · cm2. This device presents the highest BV, as well as one of the best BV and R on,sp trade-offs, in all the reported MBDS devices. The R on,sp is lower than the performance limit of conventional BDS realized by two discrete devices. This 3.3 kV GaN MBDS opens the door for developing new circuit topologies and advancing system performance in medium-voltage power electronics.

42 ENGINEERING↗
DOE OSTI2020

Device-Level Multidimensional Thermal Dynamics With Implications for Current and Future Wide Bandgap Electronics

Researchers have been extensively studying wide-bandgap (WBG) semiconductor materials such as gallium nitride (GaN) with an aim to accomplish an improvement in size, weight, and power of power electronics beyond current devices based on silicon (Si). However, the increased operating power densities and reduced areal footprints of WBG device technologies result in significant levels of self-heating that can ultimately restrict device operation through performance degradation, reliability issues, and failure. Typically, self-heating in WBG devices is studied using a single measurement technique while operating the device under steady-state direct current measurement conditions. However, for switching applications, this steady-state thermal characterization may lose significance since the high power dissipation occurs during fast transient switching events. Therefore, it can be useful to probe the WBG devices under transient measurement conditions in order to better understand the thermal dynamics of these systems in practical applications. In this work, the transient thermal dynamics of an AlGaN/GaN high electron mobility transistor (HEMT) were studied using thermoreflectance thermal imaging and Raman thermometry. Also, the proper use of iterative pulsed measurement schemes such as thermoreflectance thermal imaging to determine the steady-state operating temperature of devices is discussed. These studies are followed with subsequent transient thermal characterization to accurately probe the self-heating from steady-state down to submicrosecond pulse conditions using both thermoreflectance thermal imaging and Raman thermometry with temporal resolutions down to 15 ns.

42 ENGINEERING↗
DOE OSTI2022

High thermal conductivity and ultrahigh thermal boundary conductance of homoepitaxial AlN thin films

Wurtzite aluminum nitride (AlN) has attracted increasing attention for high-power and high-temperature operations due to its high piezoelectricity, ultrawide-bandgap, and large thermal conductivity k. The k of epitaxially grown AlN on foreign substrates has been investigated; however, no thermal studies have been conducted on homoepitaxially grown AlN. In this study, the thickness dependent k and thermal boundary conductance G of homoepitaxial AlN thin films were systematically studied using the optical pump–probe method of frequency-domain thermoreflectance. Our results show that k increases with the thickness and k values are among the highest reported for film thicknesses of 200 nm, 500 nm, and 1 μm, with values of 71.95, 152.04, and 195.71 W/(mK), respectively. Our first-principles calculations show good agreement with our measured data. Remarkably, the G between the epilayer and the substrate reported high values of 328, 477, 1180, and 2590 MW/(m 2 K) for sample thicknesses of 200 nm, 500 nm, 1 μm, and 3 μm, respectively. The high k and ultrahigh G of homoepitaxially grown AlN are very promising for efficient heat dissipation, which helps in device design and has advanced applications in micro-electromechanical systems, ultraviolet photonics, and high-power electronics.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Device-Level Thermal Management of Gallium Oxide Field-Effect Transistors

The ultra-wide bandgap (~4.8 eV) and melt-grown substrate availability of β-Ga 2 O 3 gives promise to the development of next generation power electronic devices with dramatically improved size, weight, power, and efficiency over current state-of-the-art wide bandgap devices based on 4H-SiC and GaN. Also, with recent advancements made in GHz frequency RF applications, the potential for monolithic or heterogenous integration of RF and power switches has attracted researchers’ attention. Yet, it is expected that Ga 2 O 3 devices will suffer from self-heating due to the poor thermal conductivity of the material. Thermoreflectance thermal imaging and infrared thermography were used to understand the thermal characteristics of a MOSFET fabricated via homo-epitaxy. A 3D coupled electro-thermal model was constructed based on the electrical and thermal characterization results. The device model shows that a homo-epitaxial device suffers from an unacceptable junction temperature rise of ~1500°C under a targeted power density of 10 W/mm indicating the importance of employing device level thermal managements to individual Ga 2 O 3 transistors. The effectiveness of various active and passive cooling solutions was tested to achieve a goal of reducing the device operating temperature below 200°C at a power density of 10 W/mm. Results show that flip-chip hetero-integration is a viable option to enhance both the steady-state and transient thermal characteristics of Ga 2 O 3 devices without sacrificing the intrinsic advantage of high-quality native substrates. Also, it is not an active thermal management solution that entails peripherals requiring additional size and cost implications.

42 ENGINEERING↗
DOE OSTI2026

The Heterogeneous Integration of Electronic Components

Heterogeneous integration (HI) of electronics components is broadly recognized as a powerful and crucial enabler for the continued growth of computing and communication. From 2010 onwards, the value of HI is increasingly visible in the advanced packaging used in artificial intelligence, high-performance computing, smartphones and communications product implementations. In this Perspective, we argue that HI is crucial to semiconductors and more broadly to the continued evolution of computing and communications. We use leading-edge advanced packaging examples to represent the value, advancements and opportunities for HI. To succeed, it is critical to develop comprehensive HI roadmaps that inform collaborations across the design, manufacturing and reliability spectrum between systems architects, packaging and semiconductor technologists to common goals. Although this article does not provide a full roadmap, we instead detail additional parameters for artificial intelligence, smartphone and other cellular communication devices, and their constituent building blocks including interconnects, power electronics, photonics, thermal management, reliability, modelling and co-design, to foster greater collaboration opportunities among academia, research laboratories and industry.

42 ENGINEERING↗
DOE OSTI2023

Quantification of storage required for preserving frequency security in wind‐integrated systems

Abstract The penetration of wind power generation into the power grid has been accelerated in recent times due to the aggressive emission targets set by governments and other regulatory authorities. Although wind power has the advantage of being environment‐friendly, wind as a resource is intermittent in nature. In addition, wind power contributes little inertia to the system as most wind turbines are connected to the grid via power electronic converters. These negative aspects of wind power pose serious challenges to the frequency security of power systems as penetration increases. In this work, an approach is proposed where an energy storage system (ESS) is used to mitigate frequency security issues of wind‐integrated systems. ESSs are well equipped to supply virtual inertia to the grid due to their fast‐acting nature, thus replenishing some of the energy storage capability of displaced inertial generation. In this work, a probabilistic approach is proposed to estimate the amount of inertia required by a system to ensure frequency security. Reduction in total system inertia due to the displacement of conventional synchronous generation by wind power generation is considered in this approach, while also taking into account the loss of inertia due to forced outages of conventional units. Monte Carlo simulation is employed for implementing the probabilistic estimation of system inertia. An ESS is then sized appropriately, using the system swing equation, to compensate for the lost inertia. The uncertainty associated with wind energy is modeled into the framework using an autoregressive moving average technique. Effects of increasing the system peak load and changing the wind profile on the expected system inertia are studied to illustrate various factors that might affect system frequency security. The proposed method is validated using the IEEE 39‐bus test system.

17 WIND ENERGY↗
DOE OSTI2022

Intersubband transitions in nonpolar and semipolar III-nitrides: Materials, devices, and applications

In the last two decades, the third-generation wide bandgap semiconductor III-nitrides have revolutionized a myriad of electronic and photonic devices and applications, including power electronics, extreme-environment electronics, RF amplifiers, and optoelectronics such as light-emitting diodes and laser diodes. Recently, III-nitride heterostructures (e.g., AlGaN/GaN) based intersubband transition (ISBT) has garnered considerable research interest for infrared (IR), terahertz (THz), and ultrafast optoelectronics (e.g., photodetectors and quantum cascade lasers) due to its large conduction band offset, large optical phonon energy, and promising room-temperature operation. This paper presents a comprehensive review on the recent progress and challenges of III-nitrides based ISBT from the perspectives of materials, structures, devices, and applications, with a focus on nonpolar and semipolar III-nitrides. Various device structures have been demonstrated for III-nitrides based ISBT, including quantum wells, dots, and wires, among which AlGaN/GaN quantum wells are the most widely used. The effects of device parameters, crystal orientations, and doping on the ISBT properties of AlGaN/GaN quantum wells are discussed. Although the room-temperature operation is still elusive, theoretical and experimental studies show that nonpolar and semipolar III-nitrides based ISBT exhibits tunable ISBT wavelength from far-IR to THz spectral range with higher efficiency compared with polar c-plane ISBT. This review can serve as a gateway to and an important reference for the recent progress and challenges of III-nitrides based ISBT and its potential applications in sensing, communication, ultrafast optoelectronics, and integrated photonics.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2019

Levelized-Cost-of-Electricity-Driven Design Optimization for Medium-Voltage Transformerless Photovoltaic Converters

Design approaches for power electronics are typically focused on efficiency and power density; however, these strategies do not guarantee cost optimality in any well-defined sense. To overcome this shortcoming, we propose a design framework that yields circuit parameters that minimize the levelized cost of electricity (LCOE) of a generation system. LCOE serves as a meaningful metric since it captures total lifetime costs - including hardware, balance of system, and maintenance costs - and includes the impacts of power conversion efficiency and revenue from harvested energy. To obtain a tractable design problem, we formulate an approximate LCOE improvement model that quantifies the changes in LCOE resulting from a candidate converter design. We apply this framework to a multilevel cascaded topology for low-voltage dc to medium-voltage ac conversion without line-frequency transformers. An example 200 kW commercial-scale system is studied and the solution yields a design with 15 cascaded stages, 98.01% efficiency, and an LCOE reduction of 2.0%.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2018

Numerical Stiffness based Simulation of Mixed Transmission Systems

Inclusion of power electronics allows increased controllability and stability in power systems. The simulation of such systems on a large-scale is challenging due to the presence of a large number of switches and nonlinear devices. This paper presents an advanced simulation algorithm to solve the aforementioned problem. The algorithm considers separation of differential algebraic equations (DAEs) on the basis of numerical stiffness and applies hybrid discretization algorithms to simulate the DAEs. The DAEs, in this paper, represent the nonlinear nonautonomous switched system dynamics of power systems. Stability analysis is performed on a general class of nonlinear nonautonomous switched systems to show the constraints under which the proposed algorithm is stable. To show the validity of the proposed algorithm, two case studies are considered: single high-voltage direct current (HVdc) substation based on the modular multilevel converter (MMC); and an example three-terminal MMC-HVdc system. Furthermore, relaxation techniques are introduced to create a stable interface for the separated DAEs. The developed algorithms are also validated with PSCAD/EMTDC-detailed reference models.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2020

Medium- and Heavy-Duty Vehicle Electrification: An Assessment of Technology and Knowledge Gaps

The objective of this assessment was to leverage current medium- and heavy-duty vehicle (MHDV) data and information to evaluate the state of commercial vehicle electrification technologies, including the following: 1. Assessment and inventory of current MHDV electrification architectures; 2. Identification and assessment of MHDV component technologies; 3. Assessment of potential performance and cost drivers; and, 4. Identification of R&D gaps where appropriate R&D and technology would accelerate commercial vehicle electrification. These gaps include shortfalls in technology, gaps in data, and inadequate knowledge and understanding. To inform this study, the National Renewable Energy Laboratory–Oak Ridge National Laboratory team examined the open literature; conducted workshops; assessed and analyzed data on more than 175 electrified MHDVs, including vehicle and powertrain specifications; and conducted one-on-one meetings with industry representatives. This systems-level information was concatenated and parsed with respect to key characteristics such as battery energy, power, and range compared across vehicle classes. Operational data of many conventional vehicles were also examined to help determine the requirements on electrified vehicle attributes such as range. Previous studies on the total cost of ownership of electrified MHDVs were reviewed to determine where improvements in technologies (efficiency, cost, maintenance) were needed to accelerate adoption. The team also assessed the state of the art in electric drivetrains for component specifications and challenges for the commercial vehicle sector, including electric machines, power electronics, and off-board high-power charging systems (extreme fast charging and beyond). The goal of this analysis was to identify the barriers to widespread adoption of commercial vehicle electrification technologies and prioritize the research and development gaps that need to be overcome to accelerate significant market penetration of these technologies.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2018

Nonpolar vertical GaN-on-GaN p–n diodes grown on free-standing $(10\bar{1}0)$ m -plane GaN substrates

We report nonpolar vertical GaN-on-GaN p–n diodes grown on m-plane free-standing substrates. Cathodoluminescence measurements showed that the nonpolar p-GaN had a high quality with very few deep-level states. The device exhibited good rectifying behaviors with a turn-on voltage of 4.0 V, on-resistance of 2.3 mΩ∙cm 2 , and high on/off ratio of 10 10 . The reverse current leakage was described by a trap-assisted space-charge- limited current conduction mechanism. The critical electrical field was calculated to be 2.0 MV/cm without field plates or edge termination. Finally, these results pave the way for development of novel nonpolar power electronics and polarization-engineering-related advanced power devices.

36 MATERIALS SCIENCE↗