	US 12,334,857 B2
	Method for ascertaining a rotary position, method for ascertaining an electrical angular position and method for driving an electric motor
Marco Bender, Sasbachwalden (DE)
Assigned to Schaeffler Technologies AG & Co. KG, Herzogenaurach (DE)
Appl. No. 18/039,025
Filed by Schaeffler Technologies AG & Co. KG, Herzogenaurach (DE)
PCT Filed May 28, 2021, PCT No. PCT/DE2021/100464 § 371(c)(1), (2) Date May 26, 2023, PCT Pub. No. WO2022/117136, PCT Pub. Date Jun. 9, 2022.
Claims priority of application No. 10 2020 132 310.7 (DE), filed on Dec. 4, 2020; and application No. 10 2021 113 301.7 (DE), filed on May 21, 2021.
Prior Publication US 2024/0007029 A1, Jan. 4, 2024
Int. Cl. H02P 8/34 (2006.01); H02P 6/12 (2006.01); H02P 6/16 (2016.01)

CPC H02P 6/16 (2013.01) [H02P 6/12 (2013.01)]

18 Claims

1. A method for ascertaining a rotary position of a rotor assigned to an electric motor which is able to rotate about an axis of rotation with respect to a stator and the rotary position of which is ascertained by at least one measurement value of a rotary sensor by virtue of at least one measurement value of the rotary sensor being compared at a first time during operation of the rotor with a stored sensor measurement value reference), comprising calculating the rotary position present at the rotor at the first time based on a comparison between a sequence of measurement values and a sequence of reference values, wherein:

the stored sensor measurement value reference includes the sequence of reference values and the reference values are previously stored measurement values of the rotary sensor at various rotary positions of the rotary sensor,

the measurement values recorded before the first time are stored as the sequence of measurement values,

the rotary sensor has at least a first sensor element and a second sensor element, and

at least one measurement value in the sequence of measurement values comprises a first partial measurement value of the first sensor element and a second partial measurement value of the second sensor element.

6. A method for ascertaining a rotary position of a rotor assigned to an electric motor which is able to rotate about an axis of rotation with respect to a stator and the rotary position of which is ascertained by at least one measurement value of a rotary sensor by virtue of at least one measurement value of the rotary sensor being compared at a first time during operation of the rotor with a stored sensor measurement value reference), comprising calculating the rotary position present at the rotor at the first time based on a comparison between a sequence of measurement values and a sequence of reference values, wherein:

the measurement values recorded before the first time are stored as the sequence of measurement values, and

the stored sensor measurement value reference has at least as many reference values in the sequence of reference values as a number of pole pairs of the electric motor.

10. A method for determining a rotary position of a rotor of an electric motor during operation of the electric motor, comprising:

receiving, from a rotary sensor, a measurement value at a first time of operation of the electric motor;

updating a sequence of measurement values to include the measurement value at the first time of operation of the electric motor, wherein the sequence of measurement values includes measurement values recorded in time prior to the first time; and

then calculating the rotary position of the rotor based on comparing the sequence of measurement values to a sensor measurement value reference, wherein:

the sensor measurement value reference includes a sequence of reference values that are previously stored measurement values of the rotary sensor at various rotary positions of the rotary sensor, and

the sequence of measurement values are compared to the sensor measurement value reference via cyclic convolution.