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

摘要

An electronically commutated electric motor includes a stator and a rotor formed as a permanent magnet. A control unit is connected to the stator and configured to energize the stator to produce a rotating magnetic field. The electric motor further includes at least one Hall sensor configured to detect at least a magnitude of a sensor magnetic field produced by a sensor magnet connected to the rotor. The electric motor also includes at least one magneto resistive sensor configured to detect an alignment of a total magnetic field during a rotor revolution of the rotor and to generate a rotor position signal representing this alignment. The total magnetic field includes the sensor magnetic field and an interference magnetic field superimposed thereon. The control unit is further configured to determine the rotor position of the rotor at least depending on the alignment of the total magnetic field.

主权项

1. 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.