Self-Sensing Hysteresis-Type Bearingless Motor

TL;DR

This paper introduces a novel self-sensing method for hysteresis-type bearingless motors that estimates rotor position using inductance variations, eliminating the need for expensive air-gap sensors, validated through simulations and experiments.

Contribution

The paper presents a new inductance-based self-sensing technique for bearingless motors, reducing reliance on costly sensors and enabling more compact high-speed motor designs.

Findings

Finite element simulations confirm feasibility.

Prototype demonstrates accurate position estimation.

Method reduces sensor costs and complexity.

Abstract

Bearingless motors use a single stator assembly to apply torque and magnetic suspension forces on the rotor, making these machines compact with frictionless operation and thus well suited to high-speed applications. One major challenge that prevents wide usage of bearingless motors is the need for air-gap position sensors, which are typically expensive. Here we present a method to estimate the radial position of a hysteresis-type bearingless motor using the inductance variation of the stator coils amplified by an injected high-frequency signal. We have carried out finite element (FE) simulations to demonstrate its feasibility, and have constructed a prototype self-sensing bearingless motor for experimental validations.