Beacon Power Corporation

Jimpo Wang

James Arseneaux

A flywheel levitation apparatus and associated method are described for use in a flywheel driven power storage system having a rotor and which provides for an upward vertical movement of the rotor along an axis of rotation. The rotor includes a rotor face defining a cutaway section. A magnetic lifting force is applied to the rotor to at least in part serve in levitating the rotor. The magnetic lifting force exhibits a modified gap sensitivity that is smaller as compared to a conventional gap sensitivity that would be exhibited in an absence of the cutaway section.

Advanced flywheel and method

Upon operation, flywheel assemblies sand other such rotational mechanisms are released by mechanical backup bearings, which then normally remain disengaged until shutdown as the flywheel assembly is levitated by the axial magnetic field. However, either due to over heating of bearings, power failure or other stimuli, flywheels often suffer a phenomenon deemed as touchdown down from the levitation state. During this touchdown event, flywheels inherently lose rotational momentum, thus ceasing to generate and release power and often cause damage to components as well as casing. Enhancements developed herein, through the introduction of the instant secondary hybrid touchdown bearing system, allow flywheels and other such systems to retain rotational momentum and continue generation of energy. Further, the instant system negates damage to system components, as well as bearing wear.

Hybrid touchdown bearing system

Electric power is stored in a flywheel assembly, from a dc power buss, and supplied to the buss, through electronics associated with a motor/generator, its rotor integral with a flywheel supported by magnetic bearings. Upon operation, the flywheel assembly is released by mechanical backup bearings which then normally remain disengaged until shutdown as the flywheel assembly is levitated by the axial magnetic field. Enhancements developed herein smooth the flux density across discontinuities or segments present in permanent magnets due to presently limited capability for manufacture of large annular magnetic members. Herein, the introduction of a medium such as a steel cylindrical member to directly interface with the rotor as opposed to the segmented permanent magnet, greatly eradicates induced eddy current and heat on the rotor. In addition, exhibited is an annularly slotted rotor which allows for greater surface area for flux absorption.

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Westford, MA, United States of America

Jimpo Wang