This paper presents an application of integral type optimal control scheme for rotor positioning of a hybrid magnetic bearing (HMB) in one degree of freedom (1-DOF) using low bias current. It is observed that higher biasing current enhances the linearity and disturbance rejection capability but at a cost of higher copper loss in the actuator. So, selection of biasing in an HMB system is very crucial. In the proposed scheme the dc biasing current can be varied by adjusting the axial offset to the rotor magnet. Analysis has been conducted to achieve the optimal biasing current for better performance of the HMB. A prototype of the HMB system has been fabricated and tested which represents quite satisfactory axial vibration characteristics under low biasing current.
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