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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 1,783 records · Page 99
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Thermal Analysis of Liquid and Air Cooling of High-Power-Density Integrated Motor Drives

Thermal management is a crucial aspect in the design of motor and drive systems. This paper introduces a coordinated cooling approach utilizing both liquid and air to enhance the integrated motor drive's power density. The proposed solution incorporates a shared water jacket to cool both the machine and power electronics, combined with forced air ventilation for the end windings and rotor. This approach is structurally simpler, less expensive, and more effective than conventional non-interacting cooling schemes. The paper addresses the modeling of key thermal features and nonlinearities including material anisotropy, contact thermal resistance, and uneven winding loss distributions. In addition, this study utilizes a more detailed model of the loss distribution among the winding turns in each slot that delivers a higher level of accuracy. Finite Element Analysis (FEA) results demonstrate the effectiveness of the integrated cooling system for efficiently cooling the designed integrated motor drive system.

42 ENGINEERING↗
DOE OSTI2025

Traction Inverter Integrated On-Board DC Fast Charging through Partial Power Processing

This paper introduces an innovative on-board integrated DC charging approach through partial power processing (PPP) in a traction inverter system. The proposed system, incorporating a series-connected partial power dual-active-bridge (DAB) converter, efficiently regulates the DC link voltage to achieve an optimal bus voltage for traction operation across a wide speed and torque range. Leveraging partial and bidirectional power processing, the battery current during charging is precisely regulated without the need for external DC-DC charging equipment, ensuring seamless integration to a DC hub with different voltage levels. This advanced integration also endows the system with bidirectional power exchange capability to/from the external DC hub, i.e., vehicle-to-DC (V2DC).

DAB↗
DOE OSTI2016

Evaluation of System-Integrated Smart Grid Devices using Software- and Hardware-in-the-Loop

This paper presents a concise description of state-of-the-art real-time simulation-based testing methods and demonstrates how they can be used independently and/or in combination as an integrated development and validation approach for smart grid DERs and systems. A three-part case study demonstrating the application of this integrated approach at the different stages of development and validation of a system-integrated smart photovoltaic (PV) inverter is also presented. Laboratory testing results and perspectives from two international research laboratories are included in the case study.

14 SOLAR ENERGY↗
DOE OSTI2023

A Hydrogen Load Modeling Method for Integrated Hydrogen Energy System Planning

The integrated hydrogen energy system incorporates hydrogen energy into the power grid, which has been recognized as a promising option for reaching a 100% renewable electricity supply. It can make a profit because the hydrogen produced can be sold as fuel or used to generate electricity for grid services. In this paper, we develop a planning model for the integrated hydrogen energy system that considers the uncertainty of the load demand, the renewable energy generation, and the market prices. To calculate the hydrogen load, we simulate the refueling operations at a hydrogen fueling station over the course of one day and generate representative load profiles with K-means clustering. Moreover, the long-term profitability of the integrated system under both current and future conditions is validated in 10-year planning results.

grid service↗
DOE OSTI2015

Integrated Charger with Wireless Charging and Boost Function for PHEV and EV Applications

Integrated charger topologies that have been researched so far with dc-dc converters and the charging functionality have no isolation in the system. Isolation is an important feature that is required for user interface systems that have grid connections and therefore is a major limitation that needs to be addressed along with the integrated functionality. The topology proposed in this paper is a unique and a first of its kind topology that integrates a wireless charging system and the boost converter for the traction drive system. The new topology is also compared with an on-board charger system from a commercial electric vehicle (EV). The ac-dc efficiency of the proposed system is 85.1% and the specific power and power density of the onboard components is ~455 W/kg and ~320 W/ .

integrated charger↗
DOE OSTI2019

Monolithic Integration of Self-Biased C -Band Circulator on SiC Substrate for GaN MMIC Applications

We have designed and fabricated the first self-biased circulator operating in C-band and monolithically integrated it with Qorvo's GaN MMIC technology by embedding a FeNi-based magnetic nanowire composite (MNC) in a 100 $μ$m thick SiC substrate. This integrated microstrip circulator shows a circulation frequency centered at 5.7 GHz, with an insertion loss of 2.7 dB and isolation of 14 dB. Additionally, the circulator demonstrated power handling of 9.6 W with continuous wave and at least 40W under pulsed conditions. This letter points a path in integrating miniaturized circulators into full-duplex GaN T/R MMICs with stringent form factor limits.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Cosimulating Integrated Energy Systems With Heterogeneous Digital Twins: Matching a Connected World

Energy system integration promises in-creased resiliency and the unlocking of synergies, while also contributing to our goal of decarbonization. It is enabled by both old and new technologies, glued together with data and digital services. Hydrolyzers, heat pumps, distributed renewable generation, smart buildings, and the digital grid edge are all currently the subject of integration with the power system and the energy sector at large. To plan and operate such a multidisciplinary and multisectoral system properly, insight, tools, and expertise are all needed. Further, this is exactly where the state of the art fails to deliver: tools for integrated energy systems (IESs) are still in their infancy, and many times, even academia treats these sectors separately, producing experts in each of them but not across.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2020

Evolution of Distributed Energy Resource Grid Interconnection Standards for Integrating Emerging Storage Technologies

Grid interconnection standards facilitate safe and reliable grid integration of distributed energy resources (DERs). Evolution of a standard for DERs is expected to capture and accommodate widely different characteristics of DER and minimize unique grid integration challenges. This makes development of a uniform grid interconnection standard for all types of DERs a challenging and an ever-evolving consideration. This paper presents a detailed timeline of evolution, from the early 2000s to 2018, of DER interconnection standards and the research that informed their development. This is followed by a review of the research topics being considered in the grid integration of Energy Storage Systems (ESSs) which are expected to have the most significant growth amongst all DER types. These help in highlighting the need for a new standard to accommodate the unique characteristics of ESSs, and where the existing DER interconnection standard frameworks may be leveraged.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2023

Verifying the Computational Integrity of Power Grid Controls with Zero-Knowledge Proof

The control of future power grids is migrating from a centralized to a distributed/decentralized scheme to enable a massive penetration of distributed energy resources with rising dependence on communication infrastructure. A common assumption made for most existing distributed/decentralized controllers is that local controllers would faithfully follow the designated controller dynamics based on the data received from communication channels. However, with increased probability of cyberattacks on Operational Technology infrastructure, such an assumption could be risky because proper execution of the controller dynamics is then built on trust in secure communication and computation. In this work, we leverage a cryptography technology known as zero-knowledge scalable transparent arguments of knowledge (zk-STARK) to verify the computational integrity of power grid control algorithms, with projected linear dynamics-based control schemes as the initial proof-of-concept test case. The method presented here converts the cybersecurity challenge of data integrity for grid control into a subset of computational integrity.

computational integrity↗
DOE OSTI2018

Studying the Impact of Distributed Solar PV on Power Systems Using Integrated Transmission and Distribution Models

Rapid growth of distributed energy resources has prompted increasing interest in integrated Transmission (T) and Distribution (D) modeling. This paper presents the results of a distributed generation from solar photovoltaics (DGPV) impact assessment study that was performed using a synthetic T &D model. The primary objective of the study was to present a new approach for DGPV impact assessment, where along with detailed models of transmission and distribution networks, consumer loads were modeled using the physics of end-use equipment, and DGPV was geographically dispersed and connected to the secondary distribution networks. The study highlights (i) how a lack of DGPV forecasting can increase the Area Control Error (ACE) at the transmission level for high penetration levels; and (ii) how capturing transmission voltage changes using integrated T &D can change simulated distribution voltage profiles and voltage regulator operations between integrated T &D and distribution-only simulations.

14 SOLAR ENERGY↗
DOE OSTI2018

Transient Stability Analysis for Offshore Wind Power Plant Integration Planning Studies - Part II: Long Term Faults

Here, this paper addresses the transient stability (also called large-signal stability) analysis of power systems for offshore wind power plant integration planning studies. In particular, this study develops a comprehensive practical methodology to assess transient stability of power systems, including rotor angle stability, voltage stability, and frequency response for large scale power systems. This methodology considers variability of the offshore wind power plants as well as the type of any faulted system' components present and is applicable to the study of both short term and long term faults. Part I of this research discussed the short term faults whereas as Part II, the present paper, discusses long term faults. This research considers the integration of offshore wind power plants into existing power systems and demonstrates the utility of this methodology through the examination of the specific case of integrating 1,000 MW of offshore wind power into the FirstEnergy/PJM service territory using a realistic model of 63k-bus test system that represents the U.S. Eastern Interconnection.

17 WIND ENERGY↗
DOE OSTI2018

Transient Stability Analysis for Offshore Wind Power Plant Integration Planning Studies - Part I: Short Term Faults

Power system planning is the process of forecasting load demand and ensuring sufficient generation and reserve capacities over some planning horizon. This process includes investigation of steady-state and dynamic operation of power system of interest. This paper addresses the transient stability (also known as large-signal stability) analysis of power systems for offshore wind power plant integration planning studies. In particular, this study develops a comprehensive practical methodology to assess transient stability of power systems, including rotor angle stability, voltage stability and frequency response for all fault types for large scale power systems. This methodology considers variability of the offshore wind power plants as well as the type of any faulted components present and is applicable to the study of both short term and long term faults, though only short term faults are considered here (long term faults are treated sequentially in a companion paper). Furthermore, this paper considers the integration of offshore wind power plants into existing power systems and demonstrates the utility of this methodology through the examination of the specific case of integrating 1,000MW of offshore wind power into the FirstEnergy/PJM service territory using a realistic model of 63k-bus test system that represents the U.S. Eastern Interconnection.

17 WIND ENERGY↗
DOE OSTI2024

Data-driven Quasi-static Surrogate Model for Nuclear-powered Integrated Energy Systems

The integration of nuclear power into energy systems presents a promising avenue to address the growing global energy demands while minimizing greenhouse gas emissions. In this paper, we introduce a data-driven quasi-static surrogate model for nuclear-powered Integrated Energy Systems (IES) that comprises various components, including a small modular reactor (SMR), energy manifold (EM), balance of plant (BOP), high-temperature steam electrolysis (HTSE), and district heating (DH) system. Traditional physics-based models for these components often entail significant computational overhead and time consumption, necessitating the development of efficient surrogate models. The development of a complete surrogate model for the IES involves the creation of individual surrogate models for each component, leveraging machine learning techniques and simulated data. These isolated surrogate models are subsequently integrated, enabling a holistic view of the IES and reducing the computational burden associated with detailed physics-based simulations. This paper outlines the development process, validation, and the performance evaluation of the surrogate models. The findings shed light on the accuracy and applicability of the surrogate models in practical scenarios, demonstrating their potential to expedite the analysis of nuclear-powered IES and inform future research and development efforts.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2021

Planar Transformer With Asymmetric Integrated Leakage Inductance Using Horizontal Air Gap

This article presents a novel planar-based transformer winding and core structure with controllable leakage inductance generation for integrated magnetics applications. As a result of limitations in integrated magnetics from the literature, a new approach is proposed utilizing semi-interleaved windings and controllable leakage via a leakage flux core leg featuring a horizontal air gap. Here, the proposed transformer design is analyzed via detailed reluctance modeling to determine closed-form equations for the magnetizing and asymmetrically distributed leakage inductances. Next, a genetic-algorithm-based multiobjective design optimization problem is developed, seeking to minimize the core and winding losses of the proposed transformer subject to a set of parametric and geometric constraints in a dc-ac dual-active-bridge topology for microinverter applications. The optimization was extended to include other integrated magnetic structures from the literature, where it is determined that the proposed transformer is superior from the perspectives of efficiency, footprint area, and parasitic capacitance. Based on the results of the optimization analysis, two designs with theoretical transformer California Energy Commission (CEC) efficiency drops (i.e., CEC efficiency reduction specifically due to the transformer loss mechanisms) of 1.19% and 0.83% were fabricated and evaluated for electrical and thermal performance in the proposed 40 V, 400 W microinverter.

42 ENGINEERING↗
DOE OSTI2024

The Integrated Reference Region Analysis for Parallel DFIGs’ Interfacing Inductors

Although the traditional design of doubly-fed induction generators (DFIGs)’ interfacing inductors consider the peak ripple of the grid-side converter (GSC)’s output current, it does not consider the inductors’ impact on DFIGs’ smallsignal stability. Located in series between the GSC and the stator, the inappropriate selection of the interfacing inductor can easily result to system instability. Therefore, this paper first proposes the integrated reference region analysis for small wind farm's interfacing inductors to improve the traditional design method. Firstly, a new detailed parallel DFIGs’ smallsignal model that considers output currents’ coupling is built in d-q coordinate system with state-space approach. The model focuses on representing the operating states of parallel DFIGs in wind farm. Secondly, the linearized state-space matrix of parallel DFIGs is decomposed into nominal-value matrix and location matrix. Considering the traditional design requirements, the integrated reference region for interfacing inductor is proposed through spectral radius and bialternate matrix sum (BMS). Furthermore, it can provide better guidance for parameter selecting and stabilization method researches. Finally, the simulation and experimental results show that the proposed integrated reference region for parallel DFIGs’ interfacing inductors is accurate and instructive.

47 OTHER INSTRUMENTATION↗
DOE OSTI2017

IGMS: An Integrated ISO-to-Appliance Scale Grid Modeling System

This paper describes the Integrated Grid Modeling System (IGMS), a novel electric power system modeling platform for integrated transmission-distribution analysis that co-simulates off-the-shelf tools on high performance computing (HPC) platforms to offer unprecedented resolution from ISO markets down to appliances and other end uses. Specifically, the system simultaneously models hundreds or thousands of distribution systems in co-simulation with detailed Independent System Operator (ISO) markets and AGC-level reserve deployment. IGMS uses a new MPI-based hierarchical co-simulation framework to connect existing sub-domain models. Our initial efforts integrate opensource tools for wholesale markets (FESTIV), bulk AC power flow (MATPOWER), and full-featured distribution systems including physics-based end-use and distributed generation models (many instances of GridLAB-D[TM]). The modular IGMS framework enables tool substitution and additions for multi-domain analyses. This paper describes the IGMS tool, characterizes its performance, and demonstrates the impacts of the coupled simulations for analyzing high-penetration solar PV and price responsive load scenarios.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2021

A Transported Livengood–Wu Integral Model for Knock Prediction in Computational Fluid Dynamics Simulation

This work describes the development of a transported Livengood–Wu (L–W) integral model for computational fluid dynamics (CFD) simulation to predict autoignition and engine knock tendency. The currently employed L–W integral model considers both single-stage and two-stage ignition processes, thus can be generally applied to different fuels such as paraffin, olefin, aromatics, and alcohol. The model implementation is first validated in simulations of homogeneous charge compression ignition (HCCI) combustion for three different fuels, showing good accuracy in prediction of autoignition timing for fuels with either single-stage or two-stage ignition characteristics. Then, the L–W integral model is coupled with G-equation model to indicate end-gas autoignition and knock tendency in CFD simulations of a direct-injection spark-ignition engine. This modeling approach is about 10 times more efficient than the ones that based on detailed chemistry calculation and pressure oscillation analysis. Two fuels with same Research Octane Number (RON) but different octane sensitivity are studied, namely, Co-Optima alkylate and Co-Optima E30. Feed-forward neural network model in conjunction with multivariable minimization technique is used to generate fuel surrogates with targets of matched RON, octane sensitivity, and ethanol content. The CFD model is validated against experimental data in terms of pressure traces and heat release rate for both fuels under a wide range of operating conditions. The knock tendency—indicated by the fuel energy contained in the autoignited region—of the two fuels at different load conditions correlates well with the experimental results and the fuel octane sensitivity, implying the current knock modeling approach can capture the octane sensitivity effect and can be applied to further investigation on composition of octane sensitivity.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2018

Kernels of the Direct Collision Integral of the Nonlinear Boltzmann Equation

This paper reviews the properties of kernels of the direct collision integral describing the escape of particles from an element of the phase volume due to collisions, as well as properties of kernels of the integral operators arising in expansion of the direct collision integral in spherical harmonics. It is shown that, for isotropic scattering cross sections depending on the relative velocity by a power law, these kernels can be obtained in an analytical form. Since the analytical expressions for the kernels with large indices become too cumbersome, their asymptotics are found.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗