Magnetic bearing system including a control system for a flywheel and method for operating same

A bearing system of a flywheel for positioning and supporting a rotating assembly including a vertical shaft coincident with a main rotation axis and an attached cylinder used for energy storage and high surge power delivery, said bearing system comprising:

• first through fourth radial force generators disposed in a first plane perpendicular to the rotation axis of the rotating assembly, said first through fourth force generators including only electromagnets;
• fifth through eighth radial force generators disposed in a second plane perpendicular to the rotation axis of the rotating assembly and different than said first plane, said fifth through eighth force generators including only electromagnets;
• an upper axial force generator containing an electromagnet and a permanent magnet;
• and
• first and second means for maintaining the rotor in a predetermined cylindrical volume within the flywheel when forces generated by said first through eighth radial force generators are less than displacement force applied to the shaft.

A control system for operating a bearing system of a flywheel having first through fourth radial force generators disposed in a first plane perpendicular to the rotation axis of a rotating assembly, said first through fourth force generators including only electromagnets, fifth through eighth radial force generators disposed in a second plane perpendicular to the rotation axis of the rotating assembly and different than said first plane, said fifth through eighth force generators including only electromagnets, an upper axial force generator containing an electromagnetic and a permanent magnet, and a lower axial force generator containing an electromagnetic for positioning and supporting the rotating assembly including a vertical shaft coincident with a main rotation axis and an attached massive cylinder used for energy storage and high surge power delivery, the control system comprising:

• first through fourth sensor means for locating the rotor with respect to said first through eighth radial force generators and for generating corresponding first through fourth position signals;
• notch filter means, eliminating the synchronous runout signal generated by said control system in an operating speed range, for receiving said first through fourth position signals and a rotor speed signal and for generating first through fourth filtered signals;
• transfer function means which dynamically stabilizes said control system for receiving said filtered signal and for applying a transfer function so as to generate first through fourth transfer function signals;
• gain control means responsive to said first through fourth transfer function signals and respective first through eighth coil currents for generating respective first through fourth gain-limited signals;
• first through eighth square root circuits each receiving one of said first through fourth gain-limited signals for generating respective first through eighth square root signals;
• and
• first through eighth power amplifiers for generating respective said first through eighth coil currents responsive to respective said first through eighth square root signals,
• wherein said first through eighth coil currents excite respective ones of said first through eighth radial force generators.

A method system for operating a bearing system of a flywheel having first through fourth radial force generators disposed in a first plane perpendicular to the rotation axis of a rotating assembly, said first through fourth force generators including only electromagnets, fifth through eighth radial force generators disposed in a second plane perpendicular to the rotation axis of the rotating assembly and different than said first plane, said fifth through eighth force generators including only electromagnets, an upper axial force generator containing an electromagnetic and a permanent magnet, and a lower axial force generator containing an electromagnetic for positioning and supporting the rotating assembly including a vertical shaft coincident with a main rotation axis and an attached massive cylinder used for energy storage and high surge power delivery, the method comprising the steps of:

• locating the rotor with respect to said first through eighth radial force generators and for generating corresponding first through fourth position signals;
• eliminating the synchronous runout signal generated by said control system in an operating speed range, by receiving said first through fourth position signals and a rotor speed signal and thereby generating first through fourth filtered signals;
• dynamically stabilizing the control system by receiving said filtered signal and applying a transfer function so as to generate first through fourth transfer function signals;
• generating respective first through fourth gain-limited signals responsive;
• to said first through fourth transfer function signals and respective first through eighth coil currents;
• generating respective first through eighth square root signals responsive to said first through fourth gain-limited signals;
• and
• generating said first through eighth coil currents responsive to respective said first through eighth square root signals, each of said first through eighth coil currents exciting a respective one of said first through eighth radial force generators.