Search-based PMSM low and zero speed estimation with saliency shift compensation

Abstract

This paper presents the performance of a search-based sensorless position observer with high frequency pulsating injection under dynamic speed and load conditions in the low to zero speed region. The search-based estimation uses pre-commissioned look-up tables, which map the high-frequency current amplitudes to the mechanical rotor position and are used in the sensorless estimation of the rotor position and speed. The paper investigates the variation in these look-up tables as a function of iq-current and rotor speed. An innovative saliency shift compensation is presented to allow operation at different rotor speeds without requiring additional commissioning. Rotor position estimation results for zero, forward, and reverse speed operation for a sensorless current-controlled PMSM are presented.