Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “frequency response”

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 1,189 records · Page 66
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

A heterogeneously integrated silicon photonic/lithium niobate travelling wave electro-optic modulator

Silicon photonics is a platform that enables densely integrated photonic components and systems and integration with electronic circuits. Depletion mode modulators designed on this platform suffer from a fundamental frequency response limit due to the mobility of carriers in silicon. Lithium niobate-based modulators have demonstrated high performance, but the material is difficult to process and cannot be easily integrated with other photonic components and electronics. In this manuscript, we simultaneously take advantage of the benefits of silicon photonics and the Pockels effect in lithium niobate by heterogeneously integrating silicon photonic-integrated circuits with thin-film lithium niobate samples. We demonstrate the most CMOS-compatible thin-film lithium niobate modulator to date, which has electro-optic 3 dB bandwidths of 30.6 GHz and half-wave voltages of 6.7 V×cm. These modulators are fabricated entirely in CMOS facilities, with the exception of the bonding of a thin-film lithium niobate sample post fabrication, and require no etching of lithium niobate.

42 ENGINEERING↗
DOE OSTI2012

Design and analysis of an integrated pulse modulated s-band power amplifier in gallium nitride process

The design of power amplifiers in any semi-conductor process is not a trivia exercise and it is often encountered that the simulated solution is qualitatively different than the results obtained. Phenomena such as oscillation occurring either in-band or out of band and sometimes at subharmonic intervals, continuous spectrum noticed in some frequency bands, often referred to as chaos, and jumps and hysteresis effects can all be encountered and render a design useless. All of these problems might have been identified through a more rigorous approach to stability analysis. Designing for stability is probably the one area of amplifier design that receives the least amount of attention but incurs the most catastrophic of effects if it is not performed properly. Other parameters such as gain, power output, frequency response and even matching may suitable mitigation paths. But the lack of stability in an amplifier has no mitigating path. In addition to of loss of the design completely there are the increased production cycle costs, costs involved with investigating and resolving the problem and the costs involved with schedule slips or delays resulting from it. The Linville or Rollett stability criteria that many microwave engineers follow and rely exclusively on is not sufficient by itself to ensure a stable and robust design. It will be shown that the universal belief that unconditional stability is obtained through an analysis of the scattering matrix S to determine if 1 and |{Delta}{sub S}| < 1 is only part of the procedure and other tools must be used to validate the criteria. The research shown contributes to the state of the art by developing a more thorough stability design technique for designing amplifiers of any class, whether that be current mode or switch mode, than is currently undertaken with the goal of obtaining first pass design success.

42 ENGINEERING↗
DOE OSTI2013

New wholesale power market design using linked forward markets :

This report proposes a reformulation of U.S. ISO/RTO-managed wholesale electric power mar- kets for improved reliability and e ciency of system operations. Current markets do not specify or compensate primary frequency response. They also unnecessarily limit the participation of new technologies in reserve markets and o er insu cient economic inducements for new capacity invest- ment. In the proposed market reformulation, energy products are represented as physically-covered rm contracts and reserve products as physically-covered call option contracts. Trading of these products is supported by a backbone of linked ISO/RTO-managed forward markets with planning horizons ranging from multiple years to minutes ahead. A principal advantage of this reformulation is that reserve needs can be speci ed in detail, and resources can o er the services for which they are best suited, without being forced to conform to rigid reserve product de nitions. This should improve the business case for electric energy storage and other emerging technologies to provide reserve. In addition, the facilitation of price discovery should help to ensure e cient energy/reserve procurement and adequate levels of new capacity investment.

Silva Monroy, Cesar Augusto↗
DOE OSTI2014

Dynamic Model Validation with Governor Deadband on the Eastern Interconnection

This report documents the efforts to perform dynamic model validation on the Eastern Interconnection (EI) by modeling governor deadband. An on-peak EI dynamic model is modified to represent governor deadband characteristics. Simulation results are compared with synchrophasor measurements collected by the Frequency Monitoring Network (FNET/GridEye). The comparison shows that by modeling governor deadband the simulated frequency response can closely align with the actual system response.

dynamic↗
DOE OSTI2015

Stability of Fissile Solution Systems

A technique has been developed to model the dynamics of fissile solution systems. This technique, which can be characterized as Dynamic System Simulation (DSS), is a set of coupled nonlinear differential equations that may be solved in the time domain to simulate the dynamic behavior of the overall system. The details of model development and results have previously been documented, hence, herein only a summary is presented. Herein an extension of the modeling technique is described that uses output of the simulation models to examine stability. Simplified versions of the simulation model have been linearized and transformed into the complex plane. Transfer functions for each of the system components were developed and combined to generate overall system closed- and open-loop transfer functions. Standard linear stability analysis techniques, such as frequency response and pole configuration, were used to evaluate the stability of the system.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2015

Anomaly Detection In Additively Manufactured Parts Using Laser Doppler Vibrometery

Additively manufactured parts are susceptible to non-uniform structure caused by the unique manufacturing process. This can lead to structural weakness or catastrophic failure. Using laser Doppler vibrometry and frequency response analysis, non-contact detection of anomalies in additively manufactured parts may be possible. Preliminary tests show promise for small scale detection, but more future work is necessary.

42 ENGINEERING↗
DOE OSTI2015

Transmission and Alternatives Analysis and Strategic Stakeholder Engagement

Over the life of this 3-year agreement NREL has developed data, tools, and analyses for utilities to integrate high levels of solar, and demonstrated reliability results to produce a reduction in cost and lower overall risk for stakeholders. There were five projects that made up the Agreement 25805 portfolio, including: 1. Phase 3 of the Western Wind and Solar Integration Study which studied WECC large-scale stability and frequency response. 2. Transient Solar Model Development which developed a generic solar model for cycle-by-cycle analysis. 3. Utility Scale PV Plant Demo which demonstrated control capability on a demo plant. 4. Targeted Transmission Support which contributed to transmission planning with reinforcements 5. Strategic Stakeholder Engagement which communicated and disseminated latest research with utility and industry stakeholders so that discussions and decision-making can be informed by the most current and reliable information available.

14 SOLAR ENERGY↗
DOE OSTI2015

Area of Interest 1. Interregional Electricity Reliability Issue and Assessment Analysis

In 2010, the U.S. Department of Energy (DOE) tasked Lawrence Berkeley National Laboratory (LBNL) and the Pacific Northwest National Laboratory (PNNL), in separate contracts, to provide coordinated technical support to the electricity industry for two national electricity reliability initiatives. The first initiative focused on improving the frequency response of each of the three North American interconnections. The second initiative focused on improving industry understanding of the causes and consequences of fault-induced delayed voltage recovery, which has been observed in all three interconnections. Both initiatives were conducted in close coordination with the North American Electric Reliability Corporation (NERC) and the Western Electric Coordination Council (WECC) and involved the participation of leading utilities from across the United States. This is the final report on LBNL’s activities. It consists of summaries of each activity, including references to published documents that were prepared through the course of the project. (Activities under taken by PNNL are reported on in a separate report.)

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2016

On the Path to SunShot. Emerging Issues and Challenges in Integrating Solar with the Distribution System

This report analyzes distribution-integration challenges, solutions, and research needs in the context of distributed generation from PV (DGPV) deployment to date and the much higher levels of deployment expected with achievement of the U.S. Department of Energy's SunShot targets. Recent analyses have improved estimates of the DGPV hosting capacities of distribution systems. This report uses these results to statistically estimate the minimum DGPV hosting capacity for the contiguous United States using traditional inverters of approximately 170 GW without distribution system modifications. This hosting capacity roughly doubles if advanced inverters are used to manage local voltage and additional minor, low-cost changes could further increase these levels substantially. Key to achieving these deployment levels at minimum cost is siting DGPV based on local hosting capacities, suggesting opportunities for regulatory, incentive, and interconnection innovation. Already, pre-computed hosting capacity is beginning to expedite DGPV interconnection requests and installations in select regions; however, realizing SunShot-scale deployment will require further improvements to DGPV interconnection processes, standards and codes, and compensation mechanisms so they embrace the contributions of DGPV to system-wide operations. SunShot-scale DGPV deployment will also require unprecedented coordination of the distribution and transmission systems. This includes harnessing DGPV's ability to relieve congestion and reduce system losses by generating closer to loads; minimizing system operating costs and reserve deployments through improved DGPV visibility; developing communication and control architectures that incorporate DGPV into system operations; providing frequency response, transient stability, and synthesized inertia with DGPV in the event of large-scale system disturbances; and potentially managing reactive power requirements due to large-scale deployment of advanced inverter functions. Finally, additional local and system-level value could be provided by integrating DGPV with energy storage and 'virtual storage,' which exploits improved management of electric vehicle charging, building energy systems, and other large loads. Together, continued innovation across this rich distribution landscape can enable the very-high deployment levels envisioned by SunShot.

14 SOLAR ENERGY↗
DOE OSTI2016

High-Power Electron Accelerators for Space (and other) Applications

This is a presentation on high-power electron accelerators for space and other applications. The main points covered are: electron beams for space applications, new designs of RF accelerators, high-power high-electron mobility transistors (HEMT) testing, and Li-ion battery design. In summary, the authors have considered a concept of 1-MeV electron accelerator that can operate up to several seconds. This concept can be extended to higher energy to produce higher beam power. Going to higher beam energy requires adding more cavities and solid-state HEMT RF power devices. The commercial HEMT have been tested for frequency response and RF output power (up to 420 W). Finally, the authors are testing these HEMT into a resonant load and planning for an electron beam test in FY17.

43 PARTICLE ACCELERATORS↗
DOE OSTI2018

Acoustoelasticity Testing: Changing Boundary Conditions and Damping

A series of modal tests were performed on an acoustoelastic system to explore how changes to the air and structural components affect the acoustoelastic coupling. This work is a continuation of previous experimental and analytical efforts. Here, the test method and perturbations were much more controlled than in previous tests, resulting in more refined data. Outputs of interest here are the coupled system modes as well as the resulting frequency response for various perturbations of the coupled system. Perturbations explored in this work include mass loading the structure, changing the air damping, and changing the air boundary conditions. Results of these tests indicate that simply adding damping to the air component, using foam or other absorptive material, is not sufficient to fully decouple the system. Rather, it is preferred to employ a change to the air boundary conditions, in the form of volume inclusions or scatterers, to prevent formation of the acoustic coupled mode.

42 ENGINEERING↗
DOE OSTI2018

Unintentional Islanding Detection Performance with Mixed DER Types

Most inverters for use in distribution-connected distributed energy resource applications (distributed generation and energy storage) are tested and certified to detect and cease to energize unintentional islands on the electric grid. The requirements for the performance of islanding detection methods are specified in IEEE 1547-2018, and specified conditions for certification- type testing of islanding detection are defined in IEEE 1547.1. Such certification-type testing is designed to ensure a minimum level of confidence that these inverters will not island in field applications. However, individual inverter certification tests do not address interactions between dissimilar inverters or between inverter and synchronous machines that may occur in the field. This work investigates the performance of different inverter island detection methods for these two circumstances that are not addressed by the type testing: 1) combinations of different inverters using different types of islanding detection methods, and 2) combinations of inverters and synchronous generators. The analysis took into consideration voltage and frequency ride- through requirements as specified in IEEE 1547-2018, but did not consider grid support functionality such as voltage or frequency response. While the risk of islanding is low even in these cases, it is often difficult to deal with these scenarios in a simplified interconnection screening process. This type of analysis could provide a basis to establish a practical anti- islanding screening methodology for these complex scenarios, with the goal of reducing the number of required detailed studies. Eight generic Groups of islanding detection behavior are defined, and examples of each are used in the simulations. The results indicate that islanding detection methods lose effectiveness at significantly different rates as the composition of the distributed energy resources (DERs) varies, with some methods remaining highly effective over a wide range of conditions.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2018

Improve Replication of In-service Mechanical Environments

Structural dynamic testing is a common method for determining if the design of a component of a system will mechanically fail when deployed into its field environment. To satisfy the test's goal, the mechanical stresses must be replicated. Structural dynamic testing is commonly executed on a shaker table or a shock apparatus such as a drop table or a resonant plate. These apparatus impart a force or load on the component through a test fixture that connects the unit under test to the apparatus. Because the test fixture is directly connected to the unit under test, the fixture modifies the structural dynamics of the system, thus varying the locations and relative levels of stress on the unit under test. This may lead to a false positive or negative indication if the unit under test will fail in its field environment depending on the environment and the test fixture. This body of research utilizes topology optimization using the Plato software to design a test fixture that attaches to the unit under test that matches the dynamic impedance of the next level of assembly. The optimization's objective function is the difference between the field configuration and the laboratory configuration's frequency response functions. It was found that this objective function had many local minima and posed difficulties in converging to an acceptable solution. A case study is presented that uses this objective function and although the results are not perfect, they are quantifiably better than the current method of using a sufficiently stiff fixture.

42 ENGINEERING↗
DOE OSTI2019

Incentive-Based Control and Coordination of Distributed Energy Resources

Higher penetration of renewable generation will increase the demand for adequate (and cost-effective) controllable resources on the grid that can mitigate and contain contingencies locally before they cause a network-wide collapse. This report details a scalable hierarchical control strategy for coordinating a vast number of heterogeneous distributed energy resources (DERs) in order to provide three ancillary grid services: frequency response, regulation, and ramping reserve. The control architecture consists of 1) a Distribution Reliability Coordinator (DRC), which allocates resource responses based on their declared flexibility, 2) aggregator controllers, which control a collection of DERs, and finally, 3) DER controllers at the individual devices. Test results are provided showing scalable performance on thousands of simulated residential DERs (air conditioners and water heaters) as well as results of a hardware-in-the-loop demonstration of commercial HVAC and microgrid equipment providing real responses in coordination with a grid simulation. Technology commercialization barriers and strategy is also discussed.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2019

Photonic Software Defined Radio

Wireless links are the most popular form of communications with an ever-growing demand for speed. This has resulted in an overpopulated Radio Frequency (RF) spectrum with not enough bandwidth to meet demand. The two main tactics utilized by the wireless community to overcome this problem is to 1) put more data in a given bandwidth, i.e. higher spectral efficiency and 2) use the available bandwidth more efficiently by tuning the user’s channel (i.e. carrier frequency) to an unused part of spectrum. Higher spectral efficiency is achieved by using complex signals that carry information on both the in-phase (I) carrier and quadrature-phase (Q) carrier, known as Quadrature Amplitude Modulation (QAM), and increasing the number of levels on each carrier, known as the constellation size (4QAM, 16QAM etc.). However higher constellation sizes and higher bandwidth require higher fidelity RF signals. This project looked at a photonic-based high-fidelity RF amplitude and phase modulator which modulates the amplitude and phase of femtosecond laser pulses to generate relatively high-power complex microwave waveforms at carrier frequencies up to 70GHz. The goal of the feasibility study was to build a proof-of-concept system in a laboratory setting that demonstrates the photonic generation of QAM signals at electronically tunable RF carrier frequencies. Our lab prototype achieved a signal-to-noise-and-distortion (SINAD) ratio of 39dB over a 500MHz bandwidth. The signal-to-noise ratio (SNR) of the system was measured at 42dB over a 500MHz bandwidth which is on par with state-of-the-art. The main limitation to the SINAD was the inadequate pre-compensation of the electronic Digital-to-Analog Converter (eDAC) and amplifier frequency response as well as the noise of the measurement equipment. This was backed up by simulations which showed that with perfect pre compensation and using ideal measurement equipment, a noise limited SINAD of 47dB could be achieved. We also showed, through simulations, that multiple DACs could be “optically stacked” to achieve 54dB SINAD.

42 ENGINEERING↗
DOE OSTI2019

Multi-layer Printing of Complex Antennas Using Aerosol Jet Technology (CRADA NFE-18-07315 Final Report)

This project demonstrated the feasibility of producing multilayer radio-frequency (RF) and microwave-frequency components using aerosol jet additive manufacturing technology. Funded by the U.S. Department of energy, Advanced Manufacturing Office, this effort focused on novel stacked component designs for devices such as antennas, electronic filters, resistive/inductive/capacitive (RLC) components, and transmission lines. Our approach to RF/microwave component fabrication by aerosol jet printing has the potential to reduce component size, improve performance characteristics, and allow devices to be fabricated on non-planar surfaces. Specifically, folded micro-patch antenna designs were fabricated by stacking layers of conductors and dielectrics printed in sequence using Optomec’s aerosol jet technology. ORNL supported the effort by providing design input on printing parameters and characterizing the performance of printed structures. ORNL identified suitable stacked antenna designs, produced finite element models (FEM) in high-frequency simulation software (HFSS), and provided the designs to Optomec for printing. After printing, the devices were tested and characterized at ORNL to determine the frequency response and material characteristics of the printed components. These proof-of-principle devices will provide feedback on printing parameters, optimizations for the FEM models, and a path for more complex multilayer device designs.

42 ENGINEERING↗
DOE OSTI2020

Superconducting metamaterials - the first step toward a microwave quantum bus

Coherent manipulation of quantum states is at the core of quantum information science (QIS). Many state-of-the-art quantum systems rely on microwave fields for quantum operations. As such, the microwave electromagnetic fields serve as the ideal "quantum bus" to integrate different types of QIS systems into a hybrid quantum system. Superconducting metamaterials are artificial materials consisting of arrays of superconducting resonant microstructures with sizes much smaller than the microwave wavelengths of interest. Superconducting metamaterials are a strong candidate medium for the microwave quantum bus, because the effective impedance, field distributions, and frequency response can all be controlled by engineering the microstructures, electrical bias, and magnetic flux while maintaining extremely low loss. In this project, we investigate the fundamental unit of a superconducting metamaterial - a resonator with physical dimensions much smaller than the microwave wavelengths - using NbTiN as the working superconductor, whose high operating temperatures and magnetic fields are desirable attributes for compatibility with a wide variety of quantum systems. We first studied the properties of sputtered NbTiN thin films by correlating the film thickness with the normal state resistivity, superconducting transition temperature, and resonances of transmission line resonators made from these films. We developed a process flow and designed a coplanar waveguide platform for studying small resonators. The platform significantly shortens the turnaround times of the resonator fabrication and testing cycles. Several resonators with different designs were fabricated and tested at 4 Kelvin. Resonances were observed in some resonator testers. Potential paths for improvements and future directions are discussed.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Open Source Suite for Advanced Synchrophasor Analysis

The report presents the results of the development of the open-source suite of applications for synchrophasor analysis. The suite includes several software tools for oscillation analysis, power plant model validation, and frequency response analysis using synchrophasor measurements. All tools are based on the common framework and data sources. The developed tools have been used by different electrical utilities for synchrophasor analysis. The report includes several use cases based on the actual system PMU data.

20 FOSSIL-FUELED POWER PLANTS↗