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Results for “power conversion system”

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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Comparative Investigation of System-Level Optimized Power Conversion System Architectures to Reduce LCOE for Large-Scale PV-Plus-Storage Farms

PV-plus-storage (PVS) has become a prevalent configuration for newly commissioned large-scale solar projects. However, the optimal power conversion system (PCS) architecture has not been investigated yet. This paper first validates the limited impact of inverter cost on LCOE and then explores a system-level optimized PCS architecture with extended LCOE reduction to proliferate large-scale dispatchable solar energy. Two state-of-the-art architectures including central inverters (CI), traditional 480/600 V string inverters (SI) are compared with newly proposed medium voltage string inverters (MVSI) and multiport DC transformer (MDCT). With verified layouts and single line diagrams (SLDs) of 20 MW PVS plants, the losses and costs breakdown of different architectures are extracted and the PCS related LCOEs are derived. In this analysis, all electrical bill of materials (EBOS) elements, inverters, battery storage and its associated components, are included, whose losses and costs are obtained from markets, manufacturers, and literature. Besides, the sensitivities of PCS-related LCOEs to Inverter-Loading-Ratio (ILR) are also investigated. Here, the results show that compared with CI and SI with 1.5 kV PV, 4 kV MVSI and 34 kV MDCT present an extended LCOE reduction across all ILR from 1.0 to 3.0, making them economically favorable candidates for PVS farms.

14 SOLAR ENERGY↗
NASA NTRS2007

Initial Test Results of a Dual Closed-Brayton-Cycle Power Conversion System

The dual Brayton power conversion system constructed for NASA Glenn Research Center (GRC) was acceptance tested April 2007 at Barber-Nichols, Inc., Arvada, Colorado. This uniquely configured conversion system is built around two modified commercial Capstone C30 microturbines and employs two closed-Brayton-cycle (CBC) converters sharing a common gas inventory and common heat source. Because both CBCs share the gas inventory, behavior of one CBC has an impact on the performance of the other CBC, especially when one CBC is standby or running at a different shaft speed. Testing performed to date includes the CBCs operating at equal and unequal shaft speeds. A test was also conducted where one CBC was capped off and the other was operated as a single CBC converter. The dual Brayton configuration generated 10.6 kWe at 75 krpm and a turbine inlet temperature of 817 K. Single Brayton operation generated 14.8 kWe at 90 krpm and a turbine inlet temperature of 925 K.

Johnson, Paul K.↗
DOE OSTI2022

Modular power conversion system with galvanic insulation

A modular power conversion system is provided which includes a plurality of building blocks comprised of transformers and power conversion bridges, and a high frequency AC link that transfers power and provides galvanic isolation between the building blocks. The high frequency link includes an insulating tube separating an AC link conductor and the building blocks. The insulating tube is further provided with conductive or semiconductive layers on its inner and outer surfaces for referencing them to the electric potentials of the adjacent conductors and windings, thereby placing the high electric fields substantially directly across the tube and reducing electric fields and partial discharge or corona in the adjoining space or media. The building blocks may be arranged in multiple stacks for DC or AC interface, preferably with neutral or lower voltage connections at the outer edges of the stacks and higher voltage terminals at the centers of the stack.

24 POWER TRANSMISSION AND DISTRIBUTION↗
NASA NTRS1977

Systems definition space based power conversion systems: Executive summary

Potential space-located systems for the generation of electrical power for use on earth were investigated. These systems were of three basic types: (1) systems producing electrical power from solar energy; (2) systems producing electrical power from nuclear reactors; (3) systems for augmenting ground-based solar power plants by orbital sunlight reflectors. Configurations implementing these concepts were developed through an optimization process intended to yield the lowest cost for each. A complete program was developed for each concept, identifying required production rates, quantities of launches, required facilities, etc. Each program was costed in order to provide the electric power cost appropriate to each concept.

Source record↗
NASA NTRS1982

Laser power conversion system analysis

Orbit to orbit and orbit to ground laser power conversion systems and power transfer are discussed. A system overview is presented. Pilot program parameters are considered: SLPS assumptions are listed, a laser SPS overview is presented, specifications are listed, and SLPS coats are considered.

Source record↗
NASA NTRS1978

Hydrogen turbine power conversion system assessment

A three part technical study was conducted whereby parametric technical and economic feasibility data were developed on several power conversion systems suitable for the generation of central station electric power through the combustion of hydrogen and the use of the resulting heat energy in turbogenerator equipment. The study assessed potential applications of hydrogen-fueled power conversion systems and identified the three most promising candidates: (1) Ericsson Cycle, (2) gas turbine, and (3) direct steam injection system for fossil fuel as well as nuclear powerplants. A technical and economic evaluation was performed on the three systems from which the direct injection system (fossil fuel only) was selected for a preliminary conceptual design of an integrated hydrogen-fired power conversion system.

Wright, D. E.↗
NASA NTRS2004

Research and Technology Activities Supporting Closed-Brayton-Cycle Power Conversion System Development

The elements of Brayton technology development emphasize power conversion system risk mitigation. Risk mitigation is achieved by demonstrating system integration feasibility, subsystem/component life capability (particularly in the context of material creep) and overall spacecraft mass reduction. Closed-Brayton-cycle (CBC) power conversion technology is viewed as relatively mature. At the 2-kWe power level, a CBC conversion system Technology Readiness Level (TRL) of six (6) was achieved during the Solar Dynamic Ground Test Demonstration (SD-GTD) in 1998. A TRL 5 was demonstrated for 10 kWe-class CBC components during the development of the Brayton Rotating Unit (BRU) from 1968 to 1976. Components currently in terrestrial (open cycle) Brayton machines represent TRL 4 for similar uses in 100 kWe-class CBC space systems. Because of the baseline component and subsystem technology maturity, much of the Brayton technology task is focused on issues related to systems integration. A brief description of ongoing technology activities is given.

Barrett, Michael J.↗
NASA NTRS1976

Systems definition space-based power conversion systems

Potential space-located systems for the generation of electrical power for use on Earth are discussed and include: (1) systems producing electrical power from solar energy; (2) systems producing electrical power from nuclear reactors; and (3) systems for augmenting ground-based solar power plants by orbital sunlight reflectors. Systems (1) and (2) would utilize a microwave beam system to transmit their output to Earth. Configurations implementing these concepts were developed through an optimization process intended to yield the lowest cost for each. A complete program was developed for each concept, identifying required production rates, quantities of launches, required facilities, etc. Each program was costed in order to provide the electric power cost appropriate to each concept.

Source record↗
NASA NTRS2005

Heat Rejection Concepts for Brayton Power Conversion Systems

This paper describes potential heat rejection design concepts for closed Brayton cycle (CBC) power conversion systems. Brayton conversion systems are currently under study by NASA for Nuclear Electric Propulsion (NEP) applications. The Heat Rejection Subsystem (HRS) must dissipate waste heat generated by the power conversion system due to inefficiencies in the thermal-to-electric conversion process. Space Brayton conversion system designs tend to optimize at efficiencies of about 20 to 25 percent with radiator temperatures in the 400 to 600 K range. A notional HRS was developed for a 100 kWe-class Brayton power system that uses a pumped sodium-potassium (NaK) heat transport loop coupled to a water heat pipe radiator. The radiator panels employ a sandwich construction consisting of regularly-spaced circular heat pipes contained within two composite facesheets. Heat transfer from the NaK fluid to the heat pipes is accomplished by inserting the evaporator sections into the NaK duct channel. The paper evaluates various design parameters including heat pipe diameter, heat pipe spacing, and facesheet thickness. Parameters were varied to compare design options on the basis of NaK pump pressure rise and required power, heat pipe unit power and radial flux, radiator panel areal mass, and overall HRS mass.

Siamidis, John↗
NASA NTRS2009

Experimental and Analytical Performance of a Dual Brayton Power Conversion System

The interactions between two closed Brayton cycle (CBC) power conversion units (PCU) which share a common gas inventory and heat source have been studied experimentally using the Dual Brayton Power Conversion System (DBPCS) and analytically using the Closed- Cycle System Simulation (CCSS) computer code. Selected operating modes include steady-state operation at equal and unequal shaft speeds and various start-up scenarios. Equal shaft speed steady-state tests were conducted for heater exit temperatures of 840 to 950 K and speeds of 50 to 90 krpm, providing a system performance map. Unequal shaft speed steady-state testing over the same operating conditions shows that the power produced by each Brayton is sensitive to the operating conditions of the other due to redistribution of gas inventory. Startup scenarios show that starting the engines one at a time can dramatically reduce the required motoring energy. Although the DBPCS is not considered a flight-like system, these insights, as well as the operational experience gained from operating and modeling this system provide valuable information for the future development of Brayton systems.

Lavelle, Thomas A.↗