Flywheel system with synchronous reluctance and permanent magnet generators

Abstract

The present invention provides a flywheel system with a variable speed synchronous reluctance motor-generator and a variable speed permanent magnet generator for providing backup power. The flywheel system incorporates rotating elements supported by electromagnetic bearings. Electric power provided by the backup generator maintains electromagnetic bearing operation during that portion of the coast down period when shaft speed falls below the minimum required for operation of the synchronous reluctance motor-generator.

1 . An flywheel system comprising: 
 a rotatable assembly;    the rotatable assembly having a single axis of rotation and including a flywheel mass, a motor-generator rotor and a permanent magnet;    a fixed assembly;    the fixed assembly including a first electrical stator adjacent to the permanent magnet;    a containment enveloping the rotating assembly; and,    an electrical load critical to safe flywheel system operation electrically coupled to the first electrical stator for receiving electric power from the first electrical stator.    
     
     
         2 . The flywheel system of  claim 1  further comprising a second electrical stator adjacent to the motor-generator rotor.  
     
     
         3 . The flywheel system of  claim 2  wherein the motor-generator rotor includes a plurality of ferromagnetic reluctor poles.  
     
     
         4 . The flywheel system of  claim 3  wherein a motor-generator incorporating the second electrical stator and the motor-generator rotor is a variable speed synchronous reluctance motor generator.