Study on estimation of rotor position of self-sensing active magnetic bearings

Abstract

The self-sensing principle of self-sensing active magnetic bearings(SSAMBs) is introduced, and a self-sensing configuration based on the current amplitude modulation is explored. The inductance coefficient is the function of rotor displacement, so the voltage of the electromagnetic coil is the function of rotor displacement too. Add a high-frequency signal to the input of linear power amplifier for amplitude modulation, and then let the coil voltage go through the syntony circuit to extract the high-frequency voltage signal containing the displacement signal and perform demodulation. After commutating the demodulated voltage signal, the pulsed DC voltage signal is gained. Lastly, through the lowpass, the smooth DC voltage signal reflecting the rotor displacement is gained. Convert this signal to feedback signal to control the rotor position. Simulations are completed, and the results show that this system is successful in sensing the rotor position and this approach is feasible.