Electronically commutated electric motor comprising rotor position detection with interference field compensation

An electronically commutated electric motor comprising:

• a rotor;
• a stator;
• a control unit connected to the stator and configured to energize the stator so as to generate a rotating magnetic field;
• at least one Hall sensor configured to (i) ascertain at least one magnitude of a magnetic field that is generated by a sensor magnet connected to the rotor and (ii) generate a rotor position signal that represents the magnetic field;
• and
• at least one magnetoresistive sensor configured to (i) ascertain an alignment of a total magnetic field during a rotor revolution of the rotor and (ii) generate a rotor position signal that represents said alignment,
• wherein the total magnetic field comprises the sensor magnetic field and an interference magnetic field that is superimposed on said sensor magnetic field and is generated by at least electrical components of the electric motor, and
• wherein the control unit is connected at the input side to the rotor position sensors and is configured to ascertain the rotor position of the rotor in dependence upon the alignment of the total magnetic field, at least of a previously stored magnitude of the sensor magnetic field and a magnitude and an alignment of the interference magnetic field.