Flywheel Energy System

Abstract

An energy storage system comprises a housing and a flywheel having a drive shaft portion attached to a cylindrical ferromagnetic rotor portion. The drive shaft portion defines a substantially vertical axis about which the rotor portion is mounted for rotation.

What is claimed is: 
     
         1 . An energy storage system comprising:
 a first housing having an end face;   a flywheel having:
 a rotor, and a drive shaft defining a substantially vertical axis about which the rotor is .mounted for rotation within the first housing; 
   a permanent magnetic bearing assembly positioned between the end face and the rotor and having a permanent magnet mounted on the first housing or the rotor, and the other of the first housing or the rotor having ferromagnetic properties, to attract the rotor towards the end face;   a first mechanical bearing assembly acting between the first housing and the rotor to provide radial positioning of the rotor and to limit upward axial movement of the rotor in relation to the end face, the rotor being spaced from the end face by a clearance gap; and   a second mechanical bearing assembly spaced from the first mechanical bearing assembly along the drive shaft and acting between the first housing and the rotor to provide radial positioning of the rotor, the second mechanical bearing assembly permitting relative axial movement between the drive shaft and the first housing.   
     
     
         2 . The energy storage system according to  claim 1 , wherein the first mechanical bearing assembly also limits downward axial movement of the rotor in relation to the end face, limiting the size of the clearance gap. 
     
     
         3 . The energy storage system according to  claim 1 , wherein the permanent magnet is mounted on the end face. 
     
     
         4 . The energy storage system according to  claim 3 , wherein the end face of the first housing extends radially beyond the permanent magnet to overlie the rotor. 
     
     
         5 . The energy storage system according to  claim 4 , wherein the clearance gap is maintained beyond the permanent magnet. 
     
     
         6 . The energy storage system according to  claim 4 , further comprising a non-magnetic barrier between the permanent magnet and the end face. 
     
     
         7 . The energy storage system according to  claim 3 , wherein the permanent magnetic bearing assembly further includes:
 an annular backing plate of ferromagnetic metal mounted to a top wall surface of the first housing in stationary centered relation about the vertical axis, the backing plate having a radius greater than or equal to a radius of the rotor, the permanent magnet being attached to an undersurface of the backing plate.   
     
     
         8 . The energy storage system according to  claim 1 , wherein the permanent magnet is magnetized parallel to the vertical axis. 
     
     
         9 . The energy storage system according to  claim 1 , wherein the permanent magnet includes a layer of magnetized material. 
     
     
         10 . The energy storage system according to  claim 1 , wherein the permanent magnet includes a plurality of vertically stacked layers of magnetized material, each of the layers having its poles aligned in a same magnetic direction as any adjacent layer of the plurality of vertically stacked layers. 
     
     
         11 . The energy storage system according to  claim 10 , wherein the layer includes a plurality of elongate strips of magnetized material laid parallel to one another in a side-by-side contacting relationship. 
     
     
         12 . The energy storage system according to  claim 10 , wherein the layers are formed in a series of concentric circles of widening radius wrapped around the vertical axis, and formed of magnetized material comprised of are earth magnetic particles and a polymer binder. 
     
     
         13 . An energy storage system comprising:
 a flywheel housing;   a flywheel positioned within the flywheel housing, the flywheel having:
 a rotor, and 
 a drive shaft defining a substantially vertical axis about which the rotor is mounted for rotation within the flywheel housing; 
   a motor/generator housing detachably attached to the flywheel housing;   a motor/generator positioned within the motor/generator housing, the motor/generator being detachably attached to the rotor.   
     
     
         14 . The energy storage system according to  claim 13 , wherein the motor/generator Lousing is detachably attached to a top portion of the flywheel housing. 
     
     
         15 . The energy storage system according to  claim 13 , wherein the motor/generator comprises a coupling shaft for an axially slidable engagement with the rotor. 
     
     
         16 . The energy storage system according to  claim 13 ,
 wherein the motor/generator housing and motor/generator can be detached from the flywheel housing, and   wherein a second motor/generator housing and a second motor/generator can be detachably attached to the flywheel housing.   
     
     
         17 . The energy storage system according to  claim 16 , wherein the second motor/generator has a higher power rating than the motor/generator. 
     
     
         18 . An energy storage system comprising:
 a motor/generator housing;   a motor/generator positioned within the motor/generator housing;   a flywheel housing having a vacuum port;   a flywheel positioned within the flywheel housing, the flywheel having:
 a rotor, and 
 a drive shaft defining a substantially vertical axis about which the rotor is mounted for rotation within the flywheel housing; and 
   a vacuum, pump connected to the interior volume of the flywheel housing via the vacuum port,   wherein the vacuum pump is configured to be energized from electricity supplied by the motor/generator.   
     
     
         19 . The energy storage system according to  claim 18 , wherein the vacuum pump is configured to be energized from electricity supplied by an electrical power grid. 
     
     
         20 . The energy storage system according to  claim 19 , wherein the vacuum pump is configured to be energized from electricity supplied by the motor/generator when electricity supplied by the electrical power grid is not available.