Apparatus and method for determining a rotation angle of a rotor

1. A method for determining a rotation angle of a rotor with the aid of angle sensors in a motor, comprising:

capturing of reference values by reading signal values from the angle sensors after the rotor was brought to a predetermined rotor position;

measuring amplitude values of a magnetic field during at least one full revolution of the rotor;

computing offset values of the angle sensors by forming an average value of peak values of the magnetic field;

computing corrected amplitude values by subtraction of the offset values from the measured amplitude values;

computing amplitude difference values from the difference of the peak values of the magnetic field;

computing normalized/standardized amplitude values and of normalized/standardized reference values by division of the corrected amplitude values and the reference values with a divisor, corresponding to the half of the amplitude difference values;

computing a correction angle by computing the ATAN value of the normalized/standardized reference values; and

determining the rotation angle by computing the ATAN value of the normalized/standardized amplitude values in the X direction and in the Y direction and deduction of the correction angle.

2. The method according to claim 1 , wherein the predetermined rotor position is determined by using the magnetic field.

3. The method according to claim 1 , further comprising a constant measurement of the rotation angle.

4. The method according to claim 2 , further comprising a constant measurement of the rotation angle.

5. An apparatus for determining the rotor position of a motor, comprising:

at least one sensor for capturing a magnetic field value; and

a processor for computing the rotor position, wherein the processor is configured to:

capture of reference values by reading signal values from angle sensors after the rotor was brought to a predetermined rotor position;

measure amplitude values of a magnetic field during at least one full revolution of the rotor;

compute offset values of the angle sensors by forming an average value of peak values of the magnetic field;

compute corrected amplitude values by subtraction of the offset values from the measured amplitude values;

compute amplitude difference values from the difference of the peak values of the magnetic field;

compute normalized/standardized amplitude values and of normalized/standardized reference values by division of the corrected amplitude values and the reference values with a divisor, corresponding to the half of the amplitude difference values;

compute a correction angle by computing the ATAN value of the normalized/standardized reference values; and

determine the rotation angle by computing the ATAN value of the normalized/standardized amplitude values in the X direction and in the Y direction and deduction of the correction angle.

6. The apparatus according to claim 5 , wherein the processor is further configured to use a value of the magnetic field to determine the predetermined rotor position.

7. The apparatus according to claim 5 , wherein the processor is further configured to constantly measure the rotation angle.

8. The apparatus according to claim 6 , wherein the processor is further configured to constantly measure the rotation angle.

9. A synchronous motor, comprising:

a stator with a plurality of switchable coils;

a rotor rotatably held in the stator;

a permanent magnet mounted on an axle connected to the rotor; and

an apparatus for determining the rotor position of a motor, comprising:

at least one sensor for capturing a magnetic field value; and

a processor for computing the rotor position configured to:

capture of reference values by reading signal values from angle sensors after the rotor was brought to a predetermined rotor position;

measure amplitude values of a magnetic field during at least one full revolution of the rotor;

compute offset values of the angle sensors by forming an average value of peak values of the magnetic field;

compute corrected amplitude values by subtraction of the offset values from the measured amplitude values;

compute amplitude difference values from the difference of the peak values of the magnetic field;

compute normalized/standardized amplitude values and of normalized/standardized reference values by division of the corrected amplitude values and the reference values with a divisor, corresponding to the half of the amplitude difference values;

compute a correction angle by computing the ATAN value of the normalized/standardized reference values; and

determine the rotation angle by computing the ATAN value of the normalized/standardized amplitude values in the X direction and in the Y direction and deduction of the correction angle.

10. The synchronous motor according to claim 9 , further comprising an electronic circuit for switching the switchable coils on and off.