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Device, system, and method for measuring internal impedance of a test battery using frequency response
Battery impedance testing devices, circuits, systems, and related methods are disclosed. An impedance measurement device includes a current driver configured to generate an excitation current signal to be applied to a test battery responsive to a control signal, and a processor operably coupled with the current driver. The processor is configured to generate the control signal during an auto-ranging mode and a measuring mode. The auto-ranging mode applies the excitation current signal to the test battery over a plurality of different amplitudes to measure a response to the excitation current signal at each amplitude. The measuring mode applies the excitation current signal to the test battery for an amplitude responsive to the results of the auto-ranging mode. Improved sensitivity and resolution may be achieved for low impedance batteries with a rapid measurement time.
Structural and Material Design for Frequency-Response Using Error in Constitutive Equations Approach.
Abstract not provided.
Impacts of Topology Optimization Method Choice on Designing for Prescribed Structural Frequency Response.
Abstract not provided.
Frequency Response and Congestion Management using Multi-Terminal HVDC Overlay
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Pricing Frequency Response Market Products for Inverter-Based Resources.
Abstract not provided.
Frequency Response Analysis of the Molten Salt Demonstration Reactor Dynamic Simulation Model in Transient Simulation Framework of Reconfigurable Models (TRANSFORM)
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Experimental and computational investigation of interactive flow induced oscillations of two tandem rough cylinders at 3×10 4 ≤Re≤1.2×10 5
The interactive flow induced oscillations (FIO) of two adjacent, elastically mounted, rigid, tandem, locally-rough cylinders in transverse flow direction are analyzed utilizing two-dimensional Unsteady Reynolds-Averaged Navier-Stokes (2-D URANS) equations and verified experimentally in the proximity-wake region. Three sets of experiments and simulations (K = 600N/m, ζ = 0.14; K = 600N/m, ζ = 0.26; K = 1,200N/m, ζ = 0.26; K is spring stiffness, ζ is damping ratio) of two tandem cylinders with turbulence stimulation are tested and simulated for Reynolds number in the range of 30,000 = Re ≤ 120,000. The reduced velocity range is U* = 2.48–14.22, the mass ratio is m* = 1.343, and the center-to-center in-flow spacing to diameter ratio is d/D = 2.57. The characteristics of amplitude response, frequency response, lift force, and interactive wake patterns are presented and discussed. The trends of the amplitude and frequency responses from numerical simulations are in good agreement with experimental results. The main conclusions of Reynolds number effect on interactive flow induced oscillations are: (1) Five significant flow patterns between two tandem locally-rough cylinders for different Reynolds numbers are observed through analyzing the complex but stable interactions between vortices and cylinders. (2) In the initial and upper VIV branches, the downstream cylinder's FIO is seriously interfered by the wake of the upstream cylinder. (3) The downstream cylinder is strongly impinged by the vortices shed from the upstream cylinder resulting in nearly 180O out-of-phase oscillations in transition from VIV to galloping and in-phase oscillations in galloping.
Input-output characterization of an ultrasonic testing system by digital signal analysis
Ultrasonic test system input-output characteristics were investigated by directly coupling the transmitting and receiving transducers face to face without a test specimen. Some of the fundamentals of digital signal processing were summarized. Input and output signals were digitized by using a digital oscilloscope, and the digitized data were processed in a microcomputer by using digital signal-processing techniques. The continuous-time test system was modeled as a discrete-time, linear, shift-invariant system. In estimating the unit-sample response and frequency response of the discrete-time system, it was necessary to use digital filtering to remove low-amplitude noise, which interfered with deconvolution calculations. A digital bandpass filter constructed with the assistance of a Blackman window and a rectangular time window were used. Approximations of the impulse response and the frequency response of the continuous-time test system were obtained by linearly interpolating the defining points of the unit-sample response and the frequency response of the discrete-time system. The test system behaved as a linear-phase bandpass filter in the frequency range 0.6 to 2.3 MHz. These frequencies were selected in accordance with the criterion that they were 6 dB below the maximum peak of the amplitude of the frequency response. The output of the system to various inputs was predicted and the results were compared with the corresponding measurements on the system.
Characterization of demand response in the commercial, industrial, and residential sectors in the United States
The goal of our study is to provide an overview of demand response (DR) technologies, including standards and end uses, in the United States and describe resource characteristics and the attributes of 14 specific DR resources in the U.S. commercial, residential, and industrial sectors. The attributes reviewed for the end uses being considered are response frequency, response time, the need for and impacts of energy pre- or recharge, the cost of enabling a resource to respond to a load-curtailment signal, and the magnitude of load curtailment in a given resource. We also describe controls and communications technologies that can enable end uses to participate in DR programs. The characterization was initially developed as a foundational work to quantify hourly availability of DR resources from the selected end uses followed by a multi-laboratory effort that quantified DR's value within the Western Interconnection.
Bio-Inspired adaptive damping in hydrokinetic energy harnessing using flow-induced oscillations
A hydrokinetic energy converter using Flow Induced Oscillations (FIOs) of a one-degree-of-freedom cylinder-oscillator, with nonlinear adaptive damping and linear spring stiffness, is introduced and studied experimentally. Comparison to a linear-oscillator in FIO shows that this new converter, with velocity-proportional damping coefficient, is more effective in galloping, where both flow and cylinder speeds are higher. It also impacts VIV, since the converter is no longer restricted by fixed damping, which results either in ceasing motion due to excessive damping, or in low harnessed energy due to insufficient damping. The impact is most profound in the VIV to galloping transition where adaptive damping prevents shutting down of hydrokinetic energy conversion. Damping-to-velocity rate, linear spring-stiffness, and flow-velocity are the experimental parameters with Reynolds number 30,000 ≤ Re ≤ 120,000. Here, experimental results for amplitude response, frequency response, energy harvesting, efficiency and instantaneous energy of the converter are presented and discussed. The main conclusions are: (1) The nonlinear, adaptive, velocity-proportional damping coefficient increases the harnessed power. (2) The operational range of flow velocities increases. (3) At lower flow speeds, the adaptive damping stabilizes the unstable oscillations typically occurring in this region. (4) At higher flow speeds, adaptive damping results in higher harnessed power than constant damping, thus, better emulating passively a corresponding, natural, active motion by fish. (5) Increase of 51%–95% in converted power by the nonlinear oscillator compared to linear oscillator has been measured. (6) The adaptive damping converter reaches a plateau in harnessed efficiency at high flow velocity (fully developed galloping).
Infrared Imagery of Shuttle (IRIS). Task 2, summary report
End-to-end tests of a 16 element indium antimonide sensor array and 10 channels of associated electronic signal processing were completed. Quantitative data were gathered on system responsivity, frequency response, noise, stray capacitance effects, and sensor paralleling. These tests verify that the temperature accuracies, predicted in the Task 1 study, can be obtained with a very carefully designed electro-optical flight system. Pre-flight and inflight calibration of a high quality are mandatory to obtain these accuracies. Also, optical crosstalk in the array-dewar assembly must be carefully eliminated by its design. Tests of the scaled up tracking system reticle also demonstrate that the predicted tracking system accuracies can be met in the flight system. In addition, improvements in the reticle pattern and electronics are possible, which will reduce the complexity of the flight system and increase tracking accuracy.
A time delay controller for magnetic bearings
The control of systems with unknown dynamics and unpredictable disturbances has raised some challenging problems. This is particularly important when high system performance needs to be guaranteed at all times. Recently, the Time Delay Control has been suggested as an alternative control scheme. The proposed control system does not require an explicit plant model nor does it depend on the estimation of specific plant parameters. Rather, it combines adaptation with past observations to directly estimate the effect of the plant dynamics. A control law is formulated for a class of dynamic systems and a sufficient condition is presented for control systems stability. The derivation is based on the bounded input-bounded output stability approach using L sub infinity function norms. The control scheme is implemented on a five degrees of freedom high speed and high precision magnetic bearing. The control performance is evaluated using step responses, frequency responses, and disturbance rejection properties. The experimental data show an excellent control performance despite the system complexity.
Input-output characterization of an ultrasonic testing system by digital signal analysis
The input/output characteristics of an ultrasonic testing system used for stress wave factor measurements were studied. The fundamentals of digital signal processing are summarized. The inputs and outputs are digitized and processed in a microcomputer using digital signal processing techniques. The entire ultrasonic test system, including transducers and all electronic components, is modeled as a discrete-time linear shift-invariant system. Then the impulse response and frequency response of the continuous time ultrasonic test system are estimated by interpolating the defining points in the unit sample response and frequency response of the discrete time system. It is found that the ultrasonic test system behaves as a linear phase bandpass filter. Good results were obtained for rectangular pulse inputs of various amplitudes and durations and for tone burst inputs whose center frequencies are within the passband of the test system and for single cycle inputs of various amplitudes. The input/output limits on the linearity of the system are determined.
Variable Renewable Generation can Provide Balancing Control to the Electric Power System (Fact Sheet)
As wind and solar plants become more common in the electric power system, they may be called on to provide grid support services to help maintain system reliability. For example, through the use of inertial response, primary frequency response, and automatic generation control (also called secondary frequency response), wind power can provide assistance in balancing the generation and load on the system. These active power (i.e., real power) control services have the potential to assist the electric power system in times of disturbances and during normal conditions while also potentially providing economic value to consumers and variable renewable generation owners. This one-page, two-sided fact sheet discusses the grid-friendly support and benefits renewables can provide to the electric power system.
Rise time and response measurements on a LiSOCl2 cell
Dynamic impedance tests were performed on a 180 Ah LiSOCl2 cell in the frame of a short term work contract awarded by Aerospatiale as part of the Hermes Space Plane development work. These tests consisted of rise time and response measurements. The rise time test was performed to show the ability to deliver 4 KW, in the nominal voltage range (75-115 V), within less than 100 microseconds, and after a period at rest of 13 days. The response measurements test consisted of step response and frequency response tests. The frequency response test was performed to characterize the response of the LiSOCl2 cell to a positive or negative load step of 10 A starting from various currents. The test was performed for various depths of discharge and various temperatures. The test results were used to build a mathematical, electrical model of the LiSOCl2 cell which are also presented. The test description, test results, electrical modelization description, and conclusions are presented.
Investigating Power System Primary and Secondary Reserve Interaction under High Wind Power Penetration
Power system frequency needs to be maintained close to its nominal value at all times to successfully balance load and generation and maintain system reliability. Adequate primary frequency response and secondary frequency response are the primary forces to correct an energy imbalance at the second-to-minute level. As wind energy becomes a larger portion of the world's energy portfolio, there is an increased need for wind to provide frequency response. This paper addresses one of the major concerns about using wind for frequency regulation: the unknown factor of the interaction between primary and secondary reserves. The lack of a commercially available tool to model this has limited the energy industry's understanding of when the depletion of primary reserves will impact the performance of secondary response or vice versa. This paper investigates the issue by developing a multi-area frequency response integration tool with combined primary and secondary capabilities. The simulation is conducted in close coordination with economical energy scheduling scenarios to ensure credible simulation results.
Integrated tools for control-system analysis
The basic functions embedded within a user friendly software package (MATRIXx) are used to provide a high level systems approach to the analysis of linear control systems. Various control system analysis configurations are assembled automatically to minimize the amount of work by the user. Interactive decision making is incorporated via menu options and at selected points, such as in the plotting section, by inputting data. There are five evaluations such as the singular value robustness test, singular value loop transfer frequency response, Bode frequency response, steady-state covariance analysis, and closed-loop eigenvalues. Another section describes time response simulations. A time response for random white noise disturbance is available. The configurations and key equations used for each type of analysis, the restrictions that apply, the type of data required, and an example problem are described. One approach for integrating the design and analysis tools is also presented.