Position estimation of interior permanent-magnet synchronous motors based on fictitious induced EMF with switching-frequency signal injection

This paper presents a rotor position estimator based on a newly defined fictitious induced EMF for an interior permanent-magnet synchronous motor (IPMSM). The fictitious EMF is calculated easily from the stator voltage and current with its phase aligns with the rotor position. The rotor position and speed are extracted by a vector phase-locked loop. Global stability of the estimation is proven without any approximation or linearization, and no demodulation process which deteriorates the estimation bandwidth is needed.