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US 5,666,014 AGranted
Velocity-controlled magnetic bearings
AssigneeMechanical Technology Incorporated
InventorHsiang-Ming Chen
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Abstract
The invention is an actively controlled radial magnetic bearing using inexpensive and rugged search coils as sensors instead of costly and delicate displacement or position sensors. It involves a feedback control scheme totally different from the conventional PID control algorithm. It comprises a velocity estimator with search coil signals as input, a velocity feedback controller with high-frequency gain and phase modification for the purpose of controlling flexible rotors, a self-starter automating the levitation, and a unique design and tuning method of analysis.
Claims5
A radial bearing apparatus comprising:
- a stator of electromagnets;
- a rotor journaled for rotation within said stator;
- said stator including a plurality of search coils and magnetizing coils, said search coils measuring signals related to velocity of said rotor;
- a velocity estimator receiving voltage signals from said search coils and producing a velocity signal of said rotor;
- and
- a velocity feedback controller comprising:
- a velocity trimmer responsive to said velocity signal from said velocity estimator;
- a zero force seeking loop responsive to said velocity trimmer;
- a high-frequency gain and phase compensator responsive to said zero force seeking loop;
- a summer responsive to said compensator and a feed forward control signal;
- and
- a self-starter in communication with said velocity feedback controller.
9 more elements
Dependencies are inferred from the claim text.