Title :
Modeling and control of a new horizontal-shaft hybrid-type magnetic bearing
Author :
Mukhopadhyay, S.C. ; Ohji, Takahisa ; Iwahara, Masayoshi ; Yamada, Sotoshi
Author_Institution :
Fac. of Eng., Kanazawa Univ., Japan
fDate :
2/1/2000 12:00:00 AM
Abstract :
This paper reports on the development of a new horizontal-shaft hybrid-type magnetic bearing system. The bearing system will be used for a horizontal-shaft machine. The rotor is levitated due to the repulsive force between a stator and a rotor permanent magnet (PM). A lower cost and higher radial stiffness have been achieved by using a strontium-ferrite magnet on the rotor and an Nd-Fe-B PM above and below the rotor magnet. A finite-element analysis was performed to calculate the levitation force and radial stiffness. An upper stator magnet subtending an angle of 45° provides the best compromise between a large levitation force and radial stiffness. A model for the horizontal-shaft hybrid magnetic bearing system has been developed and includes the effect of the rotor dynamics and the electromagnetic forces. An integral servocontroller was designed to stabilize the axial position. The controller has been implemented in a digital signal processor. Experimental results performed on a prototype system are in agreement with the theoretical results
Keywords :
digital control; digital signal processing chips; electromagnetic forces; finite element analysis; induction motors; machine bearings; machine control; magnetic bearings; magnetic levitation; position control; rotors; servomechanisms; stability; stators; Nd-Fe-B PM; axial position stabilisation; digital signal processor; electromagnetic forces; finite-element analysis; horizontal-shaft hybrid-type magnetic bearing; horizontal-shaft machine; induction motors; integral servocontroller; levitation force; magnetic levitation; radial stiffness; repulsive force; rotor; rotor dynamics; rotor permanent magnet; stator; stator magnet; strontium-ferrite magnet; Costs; Electromagnetic forces; Electromagnetic modeling; Finite element methods; Magnetic analysis; Magnetic levitation; Performance analysis; Permanent magnets; Stators; Strontium;
Journal_Title :
Industrial Electronics, IEEE Transactions on