Airfoil-magnetic hybrid bearing and a control system thereof

A control system for airfoil-magnetic hybrid bearing comprising:

• an airfoil-magnetic hybrid bearing including a housing around the outer surface of a rotating shaft of a rotation device, an airfoil bearing positioned between the housing and the rotating shaft for generating dynamic pressure to levitate and support the rotating shaft during rotation of the rotating shaft, and a magnetic bearing positioned between the airfoil bearing and the housing to levitate the rotating shaft with a magnetic attractive force;
• a position sensor sensing the vibration displacement at the center of the rotating shaft;
• a speed sensor sensing the rotating speed of the rotating shaft;
• and
• a controller controlling the magnetic bearing,
• wherein the controller operates the magnetic bearing when the rotating speed sensed by the speed sensor is below a levitation speed at which time the rotating shaft is levitated by the airfoil bearing at the levitation speed;
• wherein the controller operates the magnetic bearing when the rotating speed is in a resonant area in the vibration mode without operation of the magnetic bearing;
• and
• wherein the controller operates the magnetic bearing when the position of the rotating shaft sensed by the position sensor exceeds a predetermined vibration amplitude.