A New Rotor Displacement Self-Sensing Method for Bearingless Switched Reluctance Motor with Bipolar PWM Voltage Demodulation

Bearingless Switched Reluctance Motor (BLSRM) is widely used in high-performance vacuum system for its reliability. However, the displacement sensors occupy extra space and limited the speed performance. Thus, a rotor displacement self-sensing method based on bipolar PWM (pulse width modulation) voltage demodulation is proposed in this paper. The internal electromagnetic model is calculated, based on which the self-sensing principle is derived. The displacement could be detected by voltage changes through switching amplifier. A simulation model and the experiment platform are established to verify the feasibility of this method.