Research On Self-sensing Active Magnetic Bearing

The fundamental and the math model of Self-sensing Active Magnetic Bearing (AMB) are studied and its stability is analyzed. Two methods, which are called as a small test-signal injection and the differential transformer, are studied in order to detect the rotor displacement without sensor. The coil of the Magnetic Bearing is made to the excitation coil and the sensing coil at the same time. The small magnitude signal is injected to the input of the power amplifier. The induced carrier frequency component is detected and put into the demodulating circuit to get the rotor displacement. On the basis of emulate experiment on the self-sensing AMB system, the electro circuits of detecting displacement and power amplifier are designed. The result of experiment makes clear that the signal of displacement can be detected by using the excitation coil. Through design and machining a type of a single degree of freedom (DOF) self-sensing Active Magnetic Bearing, the method of small test-signal injection can detect the signal of displacement and the static suspension is achieved.