Method for measuring the speed of an electrical machine

摘要

In a method for measuring the speed of an electrical machine having a stator, a rotor and a winding, in particular of an electronically commutated motor, a speed-measurement signal omega is sampled, in that a measured speed value omega(k) for the rotor is determined for each of a series of sampling instants. Moreover, a moment of inertia value for the mass moment of inertia of the rotor is determined. In addition, a current signal I is sampled, in that a current value I(k) for the electrical current in the winding is determined for each of the sampling instants. An estimated value omega_s(k) for each of the measured speed values omega(k) is determined from a measured speed value omega_k(k-1) assigned to an earlier sampling instant, from the current signal I and from the moment of inertia value. A tolerance band containing the estimated value omega_s(k) is assigned to this estimated value omega_s(k). If the measured speed value omega(k) lies outside of the tolerance band, the measured speed value omega(k) is replaced by a speed value omega_k(k) that is within the tolerance band.