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 505 records · Page 28

Making Wireless Power Matter (CRADA Final Report)

The Resonant Link project team investigated the integration of their novel, self-resonant magnetic structure for electromagnetic coils into inductive wireless power transfer systems. Relative to conventional wireless power coils, their multi-layer self-resonant structure (the “MSRS”) reduces losses by up to 6x and lowers to BOM cost by up to 10x. These power-dense, cost-effective coils are a promising path towards the first value-add wireless power systems in a variety of applications, from phones to medical devices to kitchen appliances to mobile robots to electric vehicles. The researchers explored development of the power electronics for wireless power transfer systems using the multi-layer self-resonant structure (MSRS) concept that efficiently transmits power over air gaps for in-home applications, including through-wall power transfer, appliances built around the Ki and Qi standards, and other potential use cases This project specifically focused on the power electronics design, development, and testing for these applications. Resonant Link’s proprietary wireless power technology holds the promise of matching the performance of wired chargers in size and efficiency, especially when operated from a DC distribution grid.

42 ENGINEERING↗

Power Switching Device

The MOS-Controlled Thyristor is a new type of power switching device for faster and more efficient control and management of power electronics. It enables power electronic switching at frequencies of 50 to 100 thousand times a second with much lower power losses than other semiconductor devices. Advantages include electric power savings and smaller space. The device is used in motor and power controllers, AC & DC motor drives and induction heating. Early development was supported by Lewis Research Center (LEW) and other agencies. General Electric''s power semiconductor operation, the initial NASA contractor, was later purchased by Harris Semiconductor.

Source record↗

Performance Modeling and Testing of Distributed Electronics in PV Systems; NREL (National Renewable Energy Laboratory)

Computer modeling is able to predict the performance of distributed power electronics (microinverters, power optimizers) in PV systems. However, details about partial shade and other mismatch must be known in order to give the model accurate information to go on. This talk will describe recent updates in NREL’s System Advisor Model program to model partial shading losses with and without distributed power electronics, along with experimental validation results. Computer modeling is able to predict the performance of distributed power electronics (microinverters, power optimizers) in PV systems. However, details about partial shade and other mismatch must be known in order to give the model accurate information to go on. This talk will describe recent updates in NREL’s System Advisor Model program to model partial shading losses.

14 SOLAR ENERGY↗

High Power Superconducting Electron Linear Accelerators For Industrial Application

Fermilab is executing a technology development program to develop a compact yet powerful electron accelerator. We are leveraging R&D breakthroughs in SRF cavities, cost-effective radio-frequency sources, modern cryo-coolers, and high average current electron guns. We show that a single accelerator module can deliver average beam power as high as 1 MW through detailed thermal, RF, and particle simulations.

Thangaraj, Jayakar Tobin↗

Part 1: Detailed Electromagnetic Design of an Integrated and Compact 1.3 GHZ Superconducting Radio Frequency (SRF) Electron

There exists a need for compact, reliable, high-power electron sources for applications including those in water treatment, basic science, defense, and security. There also exists a need for compact electron-beam based light and power sources of various power levels and at different frequencies (mm-wave to gamma rays) for applications also in the fields of basic science, industry, and defense and security. Today’s examples of high-average-power electron sources are neither very compact nor highly efficient. The same may be said for many of the electron-beam based light sources operated worldwide for myriad of applications. Recent breakthroughs in superconducting (SC) materials technology, radio-frequency (RF) power systems, specialized cathodes, and RF cavity designs offer ways to overcome the above-mentioned shortcomings. In this report, all these new features are integrated in a comprehensive design into one promising concept for a compact superconducting RF (SRF) high-average power electron linear accelerator. This design is capable of 5-50 kW average electron beam power and continuous wave operation with the corresponding electron beam energy up to 10 MeV.

43 PARTICLE ACCELERATORS↗

Real Time Optimal Control of Supercapacitor Operation for Frequency Response

Supercapacitors are gaining wider applications in power systems due to fast dynamic response. Utilizing supercapacitors by means of power electronics interfaces for power compensation is a proven effective technique. For applications such as requency restoration if the cost of supercapacitors maintenance as well as the energy loss on the power electronics interfaces are addressed. It is infeasible to use traditional optimization control methods to mitigate the impacts of frequent cycling. This paper proposes a Front End Controller (FEC) using Generalized Predictive Control featuring real time receding optimization. The optimization constraints are based on cost and thermal management to enhance to the utilization efficiency of supercapacitors. A rigorous mathematical derivation is conducted and test results acquired from Digital Real Time Simulator are provided to demonstrate effectiveness.

24 POWER TRANSMISSION AND DISTRIBUTION↗

Sci-Sat AM: Radiation Dosimetry and Practical Therapy Solutions - 11: Commissioning of a system for the measurement of electron stopping powers

Purpose: To develop the techniques required to experimentally determine electron stopping powers for application in primary standards and dosimetry protocols. Method and Materials: A large-volume HPGe detector system (>80% efficiency) was commissioned for the measurement of high energy (5–35 MeV) electron beams. As a proof of principle the system was used with a Y-90/Sr-90 radioactive source. Thin plates of absorbing material (< 0.1 gcm-2) were then placed between the source and detector and the emerging electron spectrum was acquired. The full experimental geometry was modelled using the EGSnrc package to validate the detector design, optimize the experimental setup and compare measured and calculated spectra. Results: The biggest challenge using a beta source was to identify a robust spectral parameter to determine for each measurement. An end-point-fitting routine was used to determine the maximum energy, Emax, of the beta spectrum for each absorber thickness t. The parameter dEmax/dt is related to the electron stopping power and the same routine was applied to both measured and simulated spectra. Although the standard uncertainty in dEmax/dt was of the order of 5 %, by taking the ratio of measured and Monte Carlo values for dEmax/dt the uncertainty of the fitting routine was eliminated and the uncertainty was reduced to less than 2 %. The agreement between measurement and simulation was within this uncertainty estimate. Conclusion: The investigation confirmed the experimental approach and demonstrated that EGSnrc could accurately determine correction factors that will be required for the final measurement setup in a linac beam.

61 RADIATION PROTECTION AND DOSIMETRY↗

Wide-Bandgap Semiconductor Amplifiers for Fusion Plasma Heating and Control

This paper discusses power electronics developed under the ARPA-E GAMOW program to support nuclear fusion power production. The goal of this project was to develop and assess the potential for wide-bandgap (WBG) semiconductor devices in power electronics to enable high-efficiency and high-voltage solid-state systems for fusion plasma generation, heating, and control. The power electronics use an architecture in which multiple high-power boards can be combined to produce megawatt-level power, where using multiple boards provides high reliability. Two main areas of power electronics boards are developed in this project for fusion plasma heating and control applications: (1) pulse generation and control and (2) radiofrequency generation. The first area is for boards capable of driving high-voltage millisecond pulses at high duty cycles. The envisioned application of these pulses is in plasma control of magnetohydrodynamic instabilities, plasma position, and edge-localized modes. Pulse-width modulation allows for the implementation of a wide variety of linear and nonlinear control systems. The boards developed for this project could actuate control coils based on digital input signals and can be parallelized to provide megawatts of output power. The design of the pulse generator is a low-side load switch. A load switch was designed and constructed that utilized 2-kV-rated field-effect transistor (FET)-based cascodes developed by Qorvo under this project to perform initial testing of these cascodes. The second area is being implemented using class E amplifiers with WBG devices and a reactance steering network to handle inductive or capacitive plasma loads. Applications include ion cyclotron resonance heating (ICRH) and high-harmonic fast-wave (HHFW) heating. A class E reactance steering network is demonstrated in modeling and experiment with a resistive-inductive load that models an inductively-coupled plasma. Power combining of boards with class E reactance steering networks is also simulated and demonstrated experimentally, to enable scaling up to high power. Modeling of high-power-density cooling and remaining useful life is conducted to enable reliable, effectively cooled high-power electronics for fusion applications.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Integration Methods for High-Density Integrated Electric Drives (Final Technical Report)

The project goal was to research, design and fabricate high-power-density, high-performance SiC power electronic modules for motor drive inverters in electric vehicles (EVs) to enable the subsequent motor drive to achieve a power density of 100 kW/l. EVs use electric motors instead of internal combustion engines as the prime mover, and their core components are semiconductor-based power electronic modules. Efficient power electronic modules play a vital role in power conversion systems. The performance of power modules directly affects the energy efficiency and overall performance of electric vehicles. Therefore, it is particularly important to develop power modules with high power density and high electrical performance that will perform reliably under EV environmental conditions. To achieve these goals, advanced electronic packaging technologies are required. This report describes a 5-year effort to integrate key aspects surrounding the basic power devices into the module itself to increase power density. These include sensing and sensing readout circuits, gate driver circuits, and two-sided cooling solutions.

33 ADVANCED PROPULSION SYSTEMS↗

Robust, Rework-able Thermal Electronic Packaging: Applications in High Power TR Modules for Space

The higher output power densities required of modern radar architectures, such as the proposed DESDynI [Deformation, Ecosystem Structure, and Dynamics of Ice] SAR [Synthetic Aperture Radar] Instrument (or DSI) require increasingly dense high power electronics. To enable these higher power densities, while maintaining or even improving hardware reliability, requires improvements in integrating advanced thermal packaging technologies into radar transmit/receive (TR) modules. New materials and techniques have been studied and are now being implemented side-by-side with more standard technology typically used in flight hardware.

Hoffman, James Patrick↗

A High Power Density Power System Electronics for NASA's Lunar Reconnaissance Orbiter

A high power density, modular and state-of-the-art Power System Electronics (PSE) has been developed for the Lunar Reconnaissance Orbiter (LRO) mission. This paper addresses the hardware architecture and performance, the power handling capabilities, and the fabrication technology. The PSE was developed by NASA s Goddard Space Flight Center (GSFC) and is the central location for power handling and distribution of the LRO spacecraft. The PSE packaging design manages and distributes 2200W of solar array input power in a volume less than a cubic foot. The PSE architecture incorporates reliable standard internal and external communication buses, solid state circuit breakers and LiIon battery charge management. Although a single string design, the PSE achieves high reliability by elegantly implementing functional redundancy and internal fault detection and correction. The PSE has been environmentally tested and delivered to the LRO spacecraft for the flight Integration and Test. This modular design is scheduled to flight in early 2009 on board the LRO and Lunar Crater Observation and Sensing Satellite (LCROSS) spacecrafts and is the baseline architecture for future NASA missions such as Global Precipitation Measurement (GPM) and Magnetospheric MultiScale (MMS).

Hernandez-Pellerano, A.↗

Thermal Performance Benchmarking

The goal for this project is to thoroughly characterize the thermal performance of state-of-the-art (SOA) in-production automotive power electronics and electric motor thermal management systems. Information obtained from these studies will be used to: evaluate advantages and disadvantages of different thermal management strategies; establish baseline metrics for the thermal management systems; identify methods of improvement to advance the SOA; increase the publicly available information related to automotive traction-drive thermal management systems; help guide future electric drive technologies (EDT) research and development (R&D) efforts. The thermal performance results combined with component efficiency and heat generation information obtained by Oak Ridge National Laboratory (ORNL) may then be used to determine the operating temperatures for the EDT components under drive-cycle conditions. In FY16, the 2012 Nissan LEAF power electronics and 2014 Honda Accord Hybrid power electronics thermal management system were characterized. Comparison of the two power electronics thermal management systems was also conducted to provide insight into the various cooling strategies to understand the current SOA in thermal management for automotive power electronics and electric motors.

33 ADVANCED PROPULSION SYSTEMS↗

Thermal Performance Benchmarking: Annual Report

In FY16, the thermal performance of the 2014 Honda Accord Hybrid power electronics thermal management systems were benchmarked. Both experiments and numerical simulation were utilized to thoroughly study the thermal resistances and temperature distribution in the power module. Experimental results obtained from the water-ethylene glycol tests provided the junction-to-liquid thermal resistance. The finite element analysis (FEA) and computational fluid dynamics (CFD) models were found to yield a good match with experimental results. Both experimental and modeling results demonstrate that the passive stack is the dominant thermal resistance for both the motor and power electronics systems. The 2014 Accord power electronics systems yield steady-state thermal resistance values around 42- 50 mm to the 2nd power K/W, depending on the flow rates. At a typical flow rate of 10 liters per minute, the thermal resistance of the Accord system was found to be about 44 percent lower than that of the 2012 Nissan LEAF system that was benchmarked in FY15. The main reason for the difference is that the Accord power module used a metalized-ceramic substrate and eliminated the thermal interface material layers. FEA models were developed to study the transient performance of 2012 Nissan LEAF, 2014 Accord, and two other systems that feature conventional power module designs. The simulation results indicate that the 2012 LEAF power module has lowest thermal impedance at a time scale less than one second. This is probably due to moving low thermally conductive materials further away from the heat source and enhancing the heat spreading effect from the copper-molybdenum plate close to the insulated gate bipolar transistors. When approaching steady state, the Honda system shows lower thermal impedance. Measurement results of the thermal resistance of the 2015 BMW i3 power electronic system indicate that the i3 insulated gate bipolar transistor module has significantly lower junction-to-liquid thermal resistance as compared to the other systems. At a flow rate of 12 liters per minute, the thermal resistance of the i3 systems is only 30 percent of the Accord system and 15 percent of the LEAF system.

30 DIRECT ENERGY CONVERSION↗

Deadband Voltage Control and Power Buffering for Extreme Fast Charging Station

Voltage fluctuation is one of the most common challenges that electric vehicle charging station (EVCS) may introduce to the power grid. Local reactive power compensation (Q-compensation) capability of bi-directional electric vehicle (EV) chargers can mitigate the steady-state voltage violations caused by the EV charging itself or changes in the neighboring loads. Power buffering, using energy storage system (ESS), can be utilized to address the voltage transients (sags and swells) as a result of EV charging at the EVCS. To address PI controller’s ‘hunting’ issue, this paper proposes a Q-sign triggered deadband voltage control (V-control) method at the point of common coupling (PCC). In addition, to ensure the ramp rate of EV charging is within the allowable limits set forth by the grid code, a ramp rate control is proposed that uses the ESS as a ‘power buffer’. Lastly, different from most reported work in the literature where no explicit limit of the power electronic converters (PECs) is considered, this work considers a reasonable apparent power capacity limit of the PECs when achieving the V-control. This limit also affects the amount of active power that can be obtained from the grid, and subsequently may require ESS to function as ‘load sharing’ device to provide supplemental active power to satisfy EV load. A case study simulated in MATLAB (interfaced with PLECS) is presented to demonstrate the effectiveness of the proposed approaches for EVCS operation.

24 POWER TRANSMISSION AND DISTRIBUTION↗

Initial beam dynamics simulations of a high-average-current field-emission electron source in a superconducting radiofrequency gun

High-power electron beams are sought-after tools in support to a wide array of societal applications. This paper explores the production of high-power electron beams by combining a high-current field-emission electron source to a superconducting radio-frequency (SRF) cavity. We especially carry out beam-dynamics simulations that demonstrate the viability of the scheme to form ~ 300 kW average-power electron beam using a 1+1/2-cell SRF gun.

43 PARTICLE ACCELERATORS↗

Formation of Power-law Electron Energy Spectra in Three-dimensional Low- β Magnetic Reconnection

While observations have suggested that power-law electron energy spectra are a common outcome of strong energy release during magnetic reconnection, e.g., in solar flares, kinetic simulations have not been able to provide definite evidence of power-laws in energy spectra of nonrelativistic reconnection. By means of 3D large-scale fully kinetic simulations, we study the formation of power-law electron energy spectra in nonrelativistic low-β reconnection. We find that both the global spectrum integrated over the entire domain and local spectra within individual regions of the reconnection layer have power-law tails with a spectral index p ~ 4 in the 3D simulation, which persist throughout the nonlinear reconnection phase until saturation. In contrast, the spectrum in the 2D simulation rapidly evolves and quickly becomes soft. We show that 3D effects such as self-generated turbulence and chaotic magnetic field lines enable the transport of high-energy electrons across the reconnection layer and allow them to access several main acceleration regions. This leads to a sustained and nearly constant acceleration rate for electrons at different energies. Here, we construct a model that explains the observed power-law spectral index in terms of the dynamical balance between particle acceleration and escape from main acceleration regions, which are defined based upon a threshold for the curvature drift acceleration term. This result could be important for explaining the formation of power-law energy spectrum in solar flares.

79 ASTRONOMY AND ASTROPHYSICS↗

Performance and Reliability of Bonded Interfaces for High-Temperature Packaging. Annual Report

Current generation automotive power electronics packages utilize silicon devices and lead-free solder alloys. To meet stringent technical targets for 2020 and beyond (for cost, power density, specific power, efficiency and reliability), wide-bandgap devices are being considered since they offer advantages such as operation at higher frequencies, voltages, and temperatures. Traditional power electronics packages must be redesigned to utilize the full potential of wide-bandgap devices, and the die- and substrate-attach layers are key areas where new material development and validation is required. Present solder alloys do not meet the performance requirements for these new package designs while also meeting cost and hazardous substance restrictions. Sintered silver (Ag) promises to meet the needs for die- and substrate-attach interfaces but synthesis optimization and reliability evaluation must be completed. Sintered Ag material was proposed as an alternative solution in power electronics packages almost 20 years back. However, synthesis pressure requirements up 40 MPa caused a higher complexity in the production process and more stringent flatness specifications for the substrates. Recently, several manufacturers have developed sintered Ag materials that require lower (3-5 MPa) or even no bonding pressures. Degradation mechanisms for these sintered Ag materials are not well known and need to be addressed. We are addressing these aspects to some extent in this project. We are developing generalized (i.e., independent of geometry) stress intensity factor versus cycles-to-failure relations for sintered Ag. Because sintered Ag is a relatively new material for automotive power electronics, the industry currently does not have a good understanding of recommended synthesis parameters or expected reliability under prescribed conditions. It is an important deliverable of this project to transfer findings to industry to eliminate barriers to using sintered Ag as a viable and commercialized die- and substrate-attach material. Only a few manufacturers produce sintered Ag pastes and may consider some processing conditions as proprietary. It is the goal of this project to openly explore and define best practices in order to impact the maximum number of power electronics module manufacturers and suppliers.

30 DIRECT ENERGY CONVERSION↗