NO. 6,353,273 | Hybrid Foil-Magnetic Bearing
A method for bearing a rotor in which load is shared between a foil bearing part and a magnetic bearing part without using a calculated rotor trajectory corresponding to various rotor spin speeds. Power input to the magnetic bearing part is controlled in response to feedback of rotor position. In order to share the load on the fly so that the load is shared quickly as the rotor speed is changed, the power input is modified in response to rotor spin speed to reduce load capacity of the magnetic bearing part as rotor spin speed is increased and increase load capacity of the magnetic bearing part as rotor spin speed is decreased. Alternative methods of modifying power input include modifying integral gain and inputting rotor spin speed to an adaptive filter to continually reset the adaptive filter at the rotor spin speed. For use of the process with a thrust bearing, the magnetic and foil bearing parts are disposed on opposite sides of the thrust runner.
- March 5, 2002