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Results for “CONVERTER”

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.

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At least 361 records · Page 20

All sources NASA NTRS DOE OSTI

NASA NTRS2011

Early Oscillation Detection for Hybrid DC/DC Converter Fault Diagnosis

This paper describes a novel fault detection technique for hybrid DC/DC converter oscillation diagnosis. The technique is based on principles of feedback control loop oscillation and RF signal modulations, and Is realized by using signal spectral analysis. Real-circuit simulation and analytical study reveal critical factors of the oscillation and indicate significant correlations between the spectral analysis method and the gain/phase margin method. A stability diagnosis index (SDI) is developed as a quantitative measure to accurately assign a degree of stability to the DC/DC converter. This technique Is capable of detecting oscillation at an early stage without interfering with DC/DC converter's normal operation and without limitations of probing to the converter.

Wang, Bright L.↗

DOE OSTI2014

A New Integrated Onboard Charger and Accessory Power Converter for Plug-in Electric Vehicles

In this paper, a new approach is presented for integrating the function of onboard battery charging into the traction drive system and accessory dc-dc converter of a plug-in electric vehicle (PEV). The idea is to utilize the segmented traction drive system of a PEV as the frond converter of the charging circuit and the transformer and high voltage converter of the 14 V accessory dc-dc converter to form a galvanically isolated onboard charger. Moreover, a control method is presented for suppressing the battery current ripple component of twice the grid frequency with the reduced dc bus capacitor in the segmented inverter. The resultant integrated charger has lower cost, weight, and volume than a standalone charger due to a substantially reduced component count. The proposed integrated charger topology was verified by modeling and experimental results on a 5.8 kW charger prototype.

Su, Gui-Jia↗

DOE OSTI2015

XTL Converter

"XTL Converter" is a short Python script for electron microscopy simulation. The program takes an input crystal file in the VESTA *.XTL format and converts it to a text format readable by the multislice simulation program ìSTEM. The process of converting a crystal *.XTL file to the format used by the ìSTEM simulation program is quite tedious; it generally requires the user to select dozens or hundreds of atoms, rearranging and reformatting their position. Header information must also be reformatted to a specific style to be read by ìSTEM. "XTL Converter" simplifies this process, saving the user time and allowing for easy batch processing of crystals.

Spurgeon, Steven R↗

DOE OSTI2017

Technologies for converter topologies

In some embodiments of the disclosed inverter topologies, an inverter may include a full bridge LLC resonant converter, a first boost converter, and a second boost converter. In such embodiments, the first and second boost converters operate in an interleaved manner. In other disclosed embodiments, the inverter may include a half-bridge inverter circuit, a resonant circuit, a capacitor divider circuit, and a transformer.

24 POWER TRANSMISSION AND DISTRIBUTION↗

DOE OSTI2020

Matrix converter operation in current control mode with regulation of output voltage vector

A matrix converter system having a current control mode operation is provided. The matrix converter system includes a matrix converter that includes a plurality of switches. A unity current reference vector having an amplitude of one is determined that defines an angle and frequency of an output current vector as a function of a reference phase angle, which is a function of the output current vector and an output voltage vector representing feedback signals of a multiphase signal output to a load. The unity current reference vector is used to control the matrix converter, to cause the output current vector to be aligned with the unity current reference vector. A unity voltage reference vector having an amplitude of one is provided that defines a reference angle and frequency as a function of a zero phase angle. The output voltage vector and the unity voltage reference vector are aligned to determine the reference phase angle as an angle between the aligned output voltage vector and the output current vector.

42 ENGINEERING↗

DOE OSTI2021

Soft-switching, high performance single-phase AC-DC converter

A soft-switching, high-performance single-phase alternating current (AC)-direct current (DC) converter is provided. The AC-DC converter described herein provides a new circuit topology for single-stage, single-phase or multi-phase AC-DC power conversion with power factor correction (PFC) and galvanic isolation using a high-frequency isolation transformer. The AC-DC converter improves power conversion efficiency and power density—two of the most important metrics for a power converter. It achieves soft switching for high frequency switches in the circuit, leading to higher efficiency and lower electromagnetic interference (EMI).

Ayyanar, Rajapandian↗

DOE OSTI2022

Flexible wave energy converter

Disclosed herein are flexible wave energy converters that actuate electrical generators with dynamic strain (e.g., flexing, stretching, twisting, distension) to convert wave energy to electrical energy. The flexible wave energy converter utilizes flexible electric generators embedded throughout the wave-energy converter's flexible body.

16 TIDAL AND WAVE POWER↗

DOE OSTI2023

Control of power converters having integrated capacitor blocked transistor cells

Various examples of power converters including Integrated Capacitor Blocked Transistor (ICBT) cells and methods of control of power converters having ICBT cells are described. In one example, a power converter includes an upper arm including a plurality of upper ICBT cells connected in series to form a series connection path and a lower arm including a plurality of lower ICBT cells connected in series in the series connection path. A controller can be configured to provide a control signal pair to each of the upper ICBT cells and a complementary control signal pair to each of the lower ICBT cells to control the converter output. A capacitor voltage controller can be configured to balance a voltage potential among ICBT capacitors in at least one of the upper arm and the lower arm.

Yu, Jianghui↗

DOE OSTI2023

Flexible wave energy converter

30 DIRECT ENERGY CONVERSION↗

DOE OSTI2026

CAPTAN+X Data Converter Integration

Fermi National Accelerator Laboratory's CAPTAN (Compact And Programmable daTa Acquisition Node) series provides a flexible hardware platform for data acquisition across a range of experiments and facilities. The latest iteration, CAPTAN+X, is built around a Kintex-7 FPGA supporting four FPGA Mezzanine Card (FMC) connections. As part of a broader laboratory effort to bring facility systems under a Model-Based Systems Engineering (MBSE) framework, CAPTAN+X is one of several systems slated to be incorporated into this modeling environment in the near term. A necessary step toward that goal is incorporating the platform's core functionality, which centers on integration with the LXD31K4 FMC, a data converter module combining dual AD9652 analog-to-digital converters and dual AD9142A digital-to-analog converters. Achieving compatibility required resolving pin-mapping conflicts between the LXD31K4's High Pin Count connector and the CAPTAN+X's available pin types, adapting a Board Support Project originally written for an UltraScale-class evaluation board to the Kintex-7 architecture, replacing incompatible primitives, restructuring clock distribution, and manually configuring chip initialization in place of an unsupported soft-processor-based approach. Functional verification of the ADC and DAC channels, followed by closed-loop testing combining both converters with real-time filtering, confirmed correct operation of the integrated system. These results establish a working hardware and firmware baseline for the CAPTAN+X platform, positioning it for future inclusion in the laboratory's growing MBSE modeling effort.

Espinoza, David [Illinois U., Urbana (main)]↗

DOE OSTI2017

Decentralized Interleaving of Paralleled Dc-Dc Buck Converters

We present a decentralized control strategy that yields switch interleaving among parallel-connected dc-dc buck converters. The proposed method is based on the digital implementation of the dynamics of a nonlinear oscillator circuit as the controller. Each controller is fully decentralized, i.e., it only requires the locally measured output current to synthesize the pulse width modulation (PWM) carrier waveform and no communication between different controllers is needed. By virtue of the intrinsic electrical coupling between converters, the nonlinear oscillator-based controllers converge to an interleaved state with uniform phase-spacing across PWM carriers. To the knowledge of the authors, this work presents the first fully decentralized strategy for switch interleaving in paralleled dc-dc buck converters.

14 SOLAR ENERGY↗

DOE OSTI2021

Stacked Low-Inertia Converter or Solid-State Transformer: Modeling and Model Predictive Priority-Shifting Control for Voltage Balance

This paper presents control challenges of stacked low-inertia converter (SLIC) or cascaded reduced dc-link solid-state transformer (SST) and proposes a novel model predictive priority-shifting (MPPS) control with implicit modulator and a discrete-time large-signal model for voltage balancing and dc-link regulation. Low-inertia converters, featuring small electrolytic capacitor-less dc links, dramatically reduce cost, size, and weight compared to conventional solutions. However, without a large dc-link buffer, the input and output are tightly coupled, leading to significant control challenges. The control becomes even more challenging with these converters stacked input-series output-parallel (ISOP) for medium-voltage (MV) grid, which causes coupling between the modules besides the coupling within each module. This paper analyzes the multi-objective, multi-degree of freedom control problem, using the modular soft-switching solid-state transformer (M-S4T) as an example of the SLIC. First, distribution of control efforts under controller saturation is critical because multiple control objectives can be conflicting, especially when the module voltages are unbalanced and are being restored. The MPPS can shift the priorities to address this issue. Second, due to the low inertia and high dc-link ripple, classic space vector pulse-width modulation (SVPWM), average model with small-ripple assumption, and control design based on small-signal model cannot accurately modulate, model, and control the nonlinear reduced dc link. Therefore, a discrete-time large-signal model of the M-S4T is established to derive the predictive control in the MPPS. The MPPS and the PI control are compared in MV simulations to show the issue of applying the PI to the SLIC and the effectiveness of the MPPS for voltage balancing and dc-link regulation in a deadbeat manner. Finally, the proposed control is tested on a 5 kV ISOP SiC SST prototype to verify priority shifting to address controller saturation issue and fast and robust voltage balancing.

14 SOLAR ENERGY↗

DOE OSTI2023

Advanced Laboratory and Field Arrays: Technical Report for Performance Enhancement for Marine Energy Converter (MEC) Arrays (Task 5)

Task 5 consisted of two parts, wave energy converter (WEC) arrays and current energy converter (CEC) arrays. The two parts of the project were executed independently, and this report covers only the work on WECs. In this part of the task, the team characterized the behavior of and developed control schemes for wave energy converter (WEC) arrays that improved performance (i.e., maximized aggregate power generation and reduced the levelized cost of energy) over baseline, non-coordinated control approaches. Specifically, for WEC arrays: the team developed optimal layouts of arrays that considered the effect of WEC placement within an array on coordinated array control with real-time estimation schemes. The numerical codes developed through this task were made available to users for array design. These tools utilized existing commercial software as well as software developed within the project team.

13 HYDRO ENERGY↗

DOE OSTI2017

Decentralized Interleaving of Paralleled Dc-Dc Buck Converters: Preprint

We present a decentralized control strategy that yields switch interleaving among parallel connected dc-dc buck converters without communication. The proposed method is based on the digital implementation of the dynamics of a nonlinear oscillator circuit as the controller. Each controller is fully decentralized, i.e., it only requires the locally measured output current to synthesize the pulse width modulation (PWM) carrier waveform. By virtue of the intrinsic electrical coupling between converters, the nonlinear oscillator-based controllers converge to an interleaved state with uniform phase-spacing across PWM carriers. To the knowledge of the authors, this work represents the first fully decentralized strategy for switch interleaving of paralleled dc-dc buck converters.

14 SOLAR ENERGY↗

DOE OSTI2022

WBS: 2.2.1.407 Flexible Wave Energy Converters (FlexWEC)

Using distributed embedded energy converters (DEECs) to create flexible ocean wave energy converters (flexWECs), could revolutionize how we conceptualize ocean wave energy conversion and how we view and evaluate ocean waves as a viable source of renewable energy. Nevertheless, flexWEC research and development is nascent in nature and needs greater understanding and evaluation of its potential. The overall goals of this project, therefore, are to understand the scientific and engineering merit of flexWECs and to assess how flexWECs could be best utilized to create effective and viable converters of marine renewable energy.

DEEC-Tec↗

DOE OSTI2021

A simple convertible electrolyzer in membraneless and membrane-based modes for understanding water splitting mechanism

State-of-the-art membrane-based electrolyzers such as proton exchange membrane electrolyzer cells, are costly, susceptible to degradation, and time-consuming for electrode evaluation and triple-phase boundary electrochemical reaction studies. Here, a simple convertible electrolyzer in membraneless and membrane-based modes is proposed. For the first time, this enables comprehensive investigations of water splitting with pure water, acidic and alkaline electrolytes in one cell. With the simple electrolyzer and high-speed visualization system, the influences of flow rate, electrolytes, concentration, and Nafion membrane on the oxygen evolution reactions (OERs), hydrogen evolution reactions (HERs) and electrolyzer performance are comprehensively investigated. Visualization results reveal that water splitting only occurred at the edge between the electrode and the Nafion membrane in pure water. However, they occurred on the whole electrode surface in alkaline and acidic electrolytes, indicating easily tunable reaction sites with the convertible electrolyzer. This demonstrates the feasibility of using the simple convertible electrolyzer for understanding the water splitting mechanism. The relation between electrolyte thickness and resistances with different electrolytes is also quantified. This research provides an insight for optimizing electrochemical devices while delivering an inexpensive and fast way for electrode evaluations and electrochemical reaction studies.

25 ENERGY STORAGE↗

DOE OSTI2025

Co-design of a wave energy converter through bi-conjugate impedance matching

As with other oscillatory power conversion systems, the design of wave energy converters can be understood as an impedance matching problem. By representing the wave energy converter as a multi-port network, two separate but related impedance matching conditions can be established. Satisfying these conditions maximizes power transfer to the load. In practice, these impedance matching conditions may be used to influence the design of the system (including the hull, power take-off, controller, mooring, etc.). To this end, this paper considers some example applications of wave energy converter design with the help of the impedance matching framework.

WEC↗

DOE OSTI2026

Wave energy converter buoy for Arctic observations

Ocean observation buoys are currently powered-constrained by battery storage capacity or available solar power. Power constraints limit the number of measurements that can be made and the lifetime of the buoys. Ocean surface wave energy could be used for power production, but wave energy converters are not yet commercially available for ocean observation buoys. Here we present the design and testing of a drifting wave energy converter buoy using a pendulum transmission system (PTS). The wave energy converter buoy was designed to operate in Arctic temperatures and wave conditions, but it could be used in areas with warmer temperatures and larger waves. Field tests measured a maximum power production of 5 watts in waves with a significant wave height of 0.42 meters and a ten minute average power production of 37 milliwatts. Power production increased with the energy period and significant wave height. The energy harvesting capabilities of the PTS showed the utility of adding a wave energy conversion device to a drifting ocean observation buoy.

Arctic observations↗