Observability of Sensorless Electric Drives

TL;DR

This paper investigates the conditions under which sensorless electric drives can be observed and controlled effectively, analyzing nonlinear models and validating findings through simulations and experiments.

Contribution

It provides a local observability analysis for nonlinear models of sensorless electric drives, enhancing understanding of their operational limitations.

Findings

Observability conditions depend on operating points.

Numerical simulations confirm theoretical analysis.

Experimental data validate the observability criteria.

Abstract

Electric drives control without shaft sensors has been an active research topic for almost three decades. It consists of estimating the rotor speed and/or position from the currents and voltages measurement. This paper deals with the observability conditions of electric drives in view of sensorless control. The models of such systems are strongly nonlinear. For this reason, a local observability approach is applied to analyze the deteriorated performance of sensorless drives in some operating conditions. The validity of the observability conditions is confirmed by numerical simulations and experimental data, using an extended Kalman filter as observer.