Radial Displacement Extraction Method of BLIM based on High Frequency Signal Injection

Abstract

To achieve the radial displacement observation of bearingless induction motor (BLIM), a displacement extraction method based on high frequency signal injection is presented. According to the variation principle of the mutual inductance between torque and suspension windings, by injecting a high frequency voltage to torque winding, the induced high frequency current signal in suspension winding is detected; then the radial displacement is extracted by demodulation. Simulation results show that the radial displacement can be effectively extracted, the BLIM can operate stably under the conditions of none displacement sensor.