Title :
A PWM Harmonics Elimination Method in Simultaneous Estimation of Magnetic Field and Displacements in Bearingless Induction Motors
Author :
Chiba, Akira ; Santisteban, José Andrés
Author_Institution :
Dept. of Electr. & Electron. Eng., Tokyo Inst. of Technol., Tokyo, Japan
Abstract :
This paper introduces a novel method for simultaneous estimation of the revolving magnetic field and rotor radial displacements in bearingless induction motors. Four auxiliary windings, i.e., search coils, are wound around the stator teeth in an induction-type bearingless motor. The coils are connected to a high-frequency voltage source. The middle-point voltages between two search coils are processed with simple analog circuits to obtain radial rotor displacements. These middle-point voltages are affected by harmonic voltages generated by a general-purpose PWM inverter connected to motor terminals. Two methods of noise elimination are proposed and tested. The theoretical analysis and the successful experimental results validate the proposed approach.
Keywords :
PWM invertors; analogue circuits; coils; displacement measurement; harmonics suppression; induction motors; interference suppression; magnetic field measurement; rotors; stators; PWM harmonics elimination method; analog circuits; auxiliary windings; bearingless induction motor; general-purpose PWM inverter; harmonic voltage generation; high-frequency voltage source; magnetic field estimation; middle-point voltages; motor terminals; noise elimination methods; radial rotor displacements; rotor radial displacement estimation; search coils; stator teeth; Coils; Noise; Pulse width modulation; Rotors; Sensors; Suspensions; Windings; Bearingless motors; magnetic suspension; noise elimination; position estimation;
Journal_Title :
Industry Applications, IEEE Transactions on
DOI :
10.1109/TIA.2011.2175882
