Method for determining the absolute position of a rotor of a linear motor

A linear motor comprising:

• a stator;
• a rotor that is movable along the stator;
• an arrangement of drive magnets comprising a plurality of drive magnets arranged adjacently in a direction of movement of the rotor with a pole pitch being provided on the rotor;
• and
• a plurality of position sensors being stationarily arranged on a stationary part at a distance from one another at a sensor distance in the direction of movement of the rotor, wherein the sensor distance is greater than the pole pitch of the plurality of drive magnets,
• wherein a position sensor of the plurality of position sensors is configured to detect a magnetic field of a drive magnet of the arrangement of the drive magnets in an area of the position sensor,
• an evaluation unit is configured to determine an edge area of the arrangement of drive magnets in a direction of movement, to derive from the determined edge area of the arrangement of the drive magnets a rough position of the rotor on the stationary part and to determine from the derived rough position of the rotor and a known geometry of the rotor a specific drive magnet of the arrangement of drive magnets having a magnetic field detected by at least one position sensor of the plurality of position sensors in an area of the arrangement of drive magnets,
• wherein the at least one position sensor is further configured to determine a relative position of the measured drive magnet with respect to the at least one position sensor, and
• wherein the evaluation unit is further configured to determine an absolute position of the rotor on the stationary part from a known mounting position of the at least one position sensor on the stationary part and from the determined relative position.