Patent ID: 7248990

Claim:
A method for controlling a system including measuring the speed of an electrical machine having a stator, a rotor and a winding, the method comprising: sampling a speed-measurement signal ω(k) by determining a measured speed value ω for the rotor for each of a series of sampling instants and controlling the system using at least the speed-measurement signal ω(k); determining a moment of inertia value for a mass moment of inertia of the rotor; sampling a current signal I by determining a current value I(k) for an electrical current in the winding for each of the sampling instants; determining an estimated value ω s (k) for each of the measured speed values ω(k) using a measured speed value ω k (k−1) assigned to an earlier sampling instant, using the current signal I, and using the moment of inertia value; assigning a tolerance band containing the estimated value ω s (k) to the estimated value ω s (k); and, replacing in the measured speed value ω(k) by a corrected speed value ω k (k) that is within the tolerance band when the measured speed value ω(k) lies outside of the tolerance band.