Summary: | 碩士 === 中原大學 === 機械工程研究所 === 98 === Active Magnetic Bearing(AMB) is the electrical energy into mechanical energy (magnetic), the electromagnetic force generated by the coil so that the object can be suspended non-contact side, therefore it has unique advantages such non-contact, lubrication-free, non-noise, so paying attention to by everybody gradually. However, traditional magnetic bearing must design the closed-loop controller by feedback signal, can make the rotor stability. Therefore, position sensors are usually applied to magnetic bearing systems. However, the sensor accuracy immediately influences the price of apparatus. It could greatly reduce the cost of equipment if we don’t use position sensor. The paper is to control the AMB system without position sensors.
This thesis focuses on design of self-sensing AMB by high frequency signal injection method measurement of rotor position and established a mathematical model of unilateral magnetic bearings and it stability analyzed. High-frequency signal injection is in the power amplifier input part add a small value of voltage (current) signal, the high-frequency signal in the coil generated high frequency components, according to the amplitude of high frequency can get Rotor displacement signal then replace the traditional Active Magnetic Bearings system‘s displacement sensors.
Then design a PD controller of self-sensing active magnetic bearings, from simulation results shows the design of rotor position sensorless of high-frequency signal correspond the rotor displacement of sensors measure, also successfully verify the high frequency signal injection feasibility of the sensor rotor displacement, also be clearly seen in the self-sensing active magnetic bearings system in the instantaneous external force it have good Immunity and can effectively estimate the rotor position,lead to the high cost of magnetic levitation system, so magnetic bearing no way widely promotion and application in the industrial, the estimation and the actual displacement of error less than 0.2μm.
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