The invention discloses a bearing-free
synchronous reluctance motor rotor displacement soft measurement method, which comprises the following steps of: first establishing a back
electromotive force model of a suspension winding of a motor, namely, performing coordinate transformation on three-phase detection current and
voltage of the suspension winding, transmitting the transformed detection current and
voltage into the back
electromotive force model to generate back electromotive forces ealpha2 and ebeta2 of a
stator; then constructing an expanded
flux linkage observer of the suspension winding, namely, acquiring
flux linkage observed values Psix and Psiy by taking the back electromotive forces as input signals of the expanded
flux linkage observer; and finally constructing an expanded displacement observer, namely, performing the coordinate transformation on the three-phase detection current of a torque winding and the suspension winding by taking the flux linkage observed values Psix and Psiy as a first input
signal of the expanded displacement observer, and finally acquiring the rotor displacement observed values alpha and beta under biphase stationary coordinates by taking the transformed detection current as second and third input signals of the expanded displacement observer. A bearing-free
synchronous reluctance motor suspension
system constructed by the method saves a displacement sensor, can realize a rotor displacement soft measurement technology and the high-speed and stable suspension running of a controlled motor, and has the advantages of simple structure, easily realized
algorithm, quick dynamic response and the like.