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Title: Flywheel energy-storage-and-conversion system for photovoltaic applications. Final report

Technical Report ·
DOI:https://doi.org/10.2172/5249604· OSTI ID:5249604

Efforts to develop a magnetically suspended solar photovoltaic flywheel energy storage unit for residential applications are discussed. A 1/10-scale prototype flywheel unit, which stores 1 kWh of energy in a 400-pound, 15-inch-diameter steel rotor at a maximum of 15,000 RPM, was designed, constructed and tested. The 1/10-scale prototype unit was based on a full-scale, 40-kWh residential flywheel design and was a total system in that it included all the electrical features needed for a complete interface between a photovoltaic array and a residential or utility load. Design features of the unit, such as its magnetic bearing, motor-generator, rotor and output power-conditioning equipment, are described and test results are presented. Manufacturing cost studies of the full-scale, 40-kWh residential flywheel system are reported along with user worth studies of flywheel systems in the Northeast and Southwest. The 1/10-scale prototype test setup was modified into an advanced prototype flywheel test unit. The advanced prototype unit consisted of a simplified, two-element magnetic bearing, to reduce projected manufacturing costs, and an available GFE advanced composite rotor of 24-inch diameter and 123-pound weight and storing 1-kWh at 15,000 RPM. An objectives of this work was to gain experience in the use of such advanced rotors on magnetic suspension. The structural flexibility inherent in the GFE composite rotor was found to require redesign of the axial servo loop control system to obtain magnetic levitation. The magnetically suspended, advanced composite rotor was then spin tested at rotational speeds up to 12,000 RPM. A new full-scale design for a 20-kWh, two-element, advanced flywheel system was prepared. Simulation studies of utility-interactive residential flywheel systems are reported.

Research Organization:
Massachusetts Inst. of Technology (MIT), Lexington, MA (United States). Lincoln Lab.
DOE Contract Number:
AC02-76ET20279
OSTI ID:
5249604
Report Number(s):
DOE/ET/20279-159; ON: DE82017128
Resource Relation:
Other Information: Portions of document are illegible
Country of Publication:
United States
Language:
English