Position estimation method for self-sensing electric machines based on the direct measurement of the current slope

Tuomas Haarnoja, Teemu Halmeaho, Aino Manninen, Kari Tammi

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    1 Citation (Scopus)

    Abstract

    In self-sensing machines, the rotor displacement or angle is recovered from the wave form of the winding current simplifying thus the structure and lowering the price of the machine. This paper introduces a new technique to enable sensorless operation of a magnetic bearing or other self-sensing Pulse-Width Modulation (PWM)-fed electric machines. The approach is based on the measurement of the rate of change of the winding current at the PWM frequency. The current slope along with the current and voltage measurements is used for estimating the winding inductance, which is a dynamic function of the rotor displacement and angle. The rotor state can then be deduced by matching the estimated inductance to the inductance model. The concept is tested in a setup in which the rotor of a Switched Reluctance Machine is levitated against the gravity using feedback from a displacement sensor. The actual displacement is then compared to the estimate given by the self-sensing algorithm. The estimate is found to be accurate, but sensitive to modeling error.
    Original languageEnglish
    Title of host publication7th IET International Conference on Power Electronics, Machines and Drives, PEMD 2014
    PublisherInstitution of Engineering and Technology IET
    Number of pages6
    ISBN (Electronic)978-1-84919-815-8
    ISBN (Print)9781849198158
    DOIs
    Publication statusPublished - 2014
    MoE publication typeA4 Article in a conference publication
    Event7th IET International Conference on Power Electronics, Machines and Drives, PEMD 2014 - Manchester, United Kingdom
    Duration: 8 Apr 201410 Apr 2014

    Conference

    Conference7th IET International Conference on Power Electronics, Machines and Drives, PEMD 2014
    Abbreviated titlePEMD 2014
    CountryUnited Kingdom
    CityManchester
    Period8/04/1410/04/14

    Keywords

    • voltage measurement
    • machine control
    • reluctance machines
    • rotors
    • magnetic bearings
    • electric current measurement

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  • Cite this

    Haarnoja, T., Halmeaho, T., Manninen, A., & Tammi, K. (2014). Position estimation method for self-sensing electric machines based on the direct measurement of the current slope. In 7th IET International Conference on Power Electronics, Machines and Drives, PEMD 2014 Institution of Engineering and Technology IET. https://doi.org/10.1049/cp.2014.0391