Apparatus and method for sensorless rotor position estimation in active magnetic bearing system

The method estimates rotor position in active magnetic bearings using a Nyquist frequency voltage and state-space model to overcome sensor failure and environmental sensitivity, ensuring reliable and robust position estimation.

KR102991529B1Active Publication Date: 2026-07-15KOREA ADVANCED INST OF SCI & TECH
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Patent Information

Application Number
KR1020260092520
Authority / Receiving Office
KR · KR
Patent Type
Patents
Current Assignee / Owner
Priority Date
2025-12-30
Filing Date
2026-05-21
Publication Date
2026-07-15
Estimated Expiration
2046-05-21

AI Technical Summary

Technical Problem

Existing active magnetic bearing systems rely on position sensors that are susceptible to failure in harsh environments, requiring additional space and complicating the system's structure, and existing sensorless control methods suffer from noise and parameter sensitivity issues.

Method used

A method and device for estimating rotor position using a voltage component of the Nyquist frequency, measuring current, and applying a state-space model to correct the estimated value, eliminating the need for position sensors and improving robustness against noise and parameter changes.

Benefits of technology

Enables reliable rotor position estimation without sensors, simplifying the system structure, reducing noise, and enhancing robustness against environmental factors.

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Abstract

The present invention relates to a method for estimating a rotor position without a position sensor in an active magnetic bearing system, wherein a voltage including a voltage component of the Nyquist frequency is applied to a winding, a current flowing through the winding is measured, a state-space model including state transition equations and output equations for state variables is derived from an electrical circuit model based on the voltage applied to the winding and the current, a predicted value of the current is calculated based on the state-space model, an estimated value of the state variable is corrected based on the error between the measured value and the predicted value of the current, and the rotor position is estimated from the corrected estimated value of the state variable.
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Citation Information

Patent Citations

  • Sensorless control system of permanent magnet synchronous motor

    CN101964624A

  • magnetic sensor

    JP2007506104A

  • Active magnetic bearings with self-sensing means

    KR101006199B1

  • Method for adjusting the value of the resistance of an electromagnet in a magnetic bearing and for the sensorless determination of the position of an object mounted in a magnetic bearing, taking into account the adjusted value of the resistance

    KR1020130019409A