Method for determining a correction value which describes an angular difference between an assumed and an actual position of a d-axis, control device and inverter

Patent metadata

Field	Value
Publication number	US-11539318-B2
Application number	US-201917279319-A
Country	US
Kind code	B2
Filing date	Sep 20, 2019
Priority date	Sep 28, 2018
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

A method determines a correction value for a control device for an electric machine, which describes an angular difference between a position of a d-axis of the electric machine and an actual position of the d-axis. The correction value is determined in a rotating state of a rotor of the electric machine as a function of a d voltage value describing a d component of a stator voltage specified by the control device in the initial configuration, of a q voltage value describing a q component of the stator voltage specified by the control device in the initial configuration, of a flux value describing a magnetic flux of the rotor, a speed value describing the speed of the rotor in the rotating state, and of a calibration value describing a speed-dependent voltage error of the d component of the stator voltage.

First claim

The invention claimed is:

1. Method for determining a correction value for a control device for an electric machine, the correction value describing an angular difference between a position of a d-axis of the electric machine assumed in an initial configuration of the control device on a basis of rotor position information of a rotor position sensor and an actual position of the d-axis, a zero current being impressed in stator windings of the electric machine and the correction value being determined in a rotating state of a rotor of the electric machine as a function
of a d-voltage value describing a d-component of a stator voltage specified by the control device in the initial configuration,
of a q-voltage value describing a q-component of the stator voltage specified by the control device in the initial configuration,
of a flux value describing a magnetic flux of the rotor,
of a speed value describing a speed of the rotor in the rotating state, and
of a calibration value describing a speed-dependent voltage error of the d component of the stator voltage,
wherein the flux value is determined as a function of the d-voltage value and the q-voltage value and the speed value as an additional function of the calibration value.

2. Method according to claim 1 , wherein the calibration value is read out on a basis of the speed value from a stored characteristic diagram which assigns the calibration value to speeds of the electric machine in each case, or is fixed for a speed in the rotating state of the rotor.

3. Method according to claim 1 , wherein setpoint voltage values of a control unit of the control device are used as the predetermined stator voltage or the predetermined stator voltage is determined from output signals of a modulator unit of the control device which provides switching signals for a power unit of an inverter.

4. Method according to claim 1 , wherein the electric machine is a permanently excited electric machine and the flux value describes the magnetic flux of permanent magnets of the rotor, or wherein the electric machine is an electrically excited electric machine and the flux value describes the rotor flux concatenated with the stator.

5. Method according to claim 1 , wherein a determined correction value is rejected as unreliable if the determined flow value is above a predetermined maximum flow value and/or if the determined flow value is below a predetermined minimum flow value.

6. Method according to claim 1 , wherein the d-voltage value, the q-voltage value and the speed value are determined as a function of mean values of respective individual values acquired over an acquisition period comprising one or more complete electrical or mechanical periods.

7. Method according to claim 6 , wherein a plausibility check verifying a quasi-stationary operation of the electric machine is performed during the acquisition period of the individual values and a correction value is rejected as unreliable if the plausibility check reveals a violation of a predetermined condition for the quasi-stationary operation.

8. Method of claim 7 , wherein the condition comprises that individual values used to determine the speed value are within a predetermined speed interval and/or that a d-current value describing an average of individual values of a d-component of a stator current detected during the detection period and a q-current value describing an average of individual values of a the d-component of the stator current detected during the detection period are within a current interval comprising zero.

9. Method according to claim 7 , wherein a plurality of correction values are determined in a predetermined or predeterminable number of successive determination cycles and an overall correction value is used as the average of the correction values determined in the determination cycles, if
the number of correction values rejected as unreliable during the respective plausibility check does not exceed a predefined maximum value and/or
the deviation of the correction values determined in the determination cycles from each other does not exceed a specified deviation measure.

10. A computer program comprising program code for carrying out a method according to claim 1 , when the computer program is executed on a computing device.

11. Method for determining a correction value for a control device for an electric machine, the correction value describing an angular difference between a position of a d-axis of the electric machine assumed in an initial configuration of the control device on a basis of rotor position information of a rotor position sensor and an actual position of the d-axis, a zero current being impressed in stator windings of the electric machine and the correction value being determined in a rotating state of a rotor of the electric machine as a function:
of a d-voltage value describing a d-component of a stator voltage specified by the control device in the initial configuration,
of a q-voltage value describing a q-component of the stator voltage specified by the control device in the initial configuration,
of a flux value describing a magnetic flux of the rotor,
of a speed value describing a speed of the rotor in the rotating state, and
of a calibration value describing a speed-dependent voltage error of the d component of the stator voltage,
wherein the following equation is evaluated to determine the correction value:
Δγ=γ tan(ω el ·Ψ·u d −Δu d ·u q , Δu d ·u d +ω el ·Ψ·u q ),

where
α tan(x, y) describes an arc tangent function or an arc cotangent function, in particular

arctan
⁡

(

x
y

)

⁢

⁢
or
⁢

⁢

arccot
⁡

(

y
x

)

or α tan 2(x, y) or α cot 2(y, x),
u d describes the d-voltage value,
u q describes the q-voltage value,
Ψ describes the flux value,
ω el describes the speed value, and
Δu d describes the calibration value.

12. A control device for an electric machine, which is arranged to impress a zero current into stator windings of the electric machine, and to determine a correction value describing an angular difference between a position of a d-axis of the electric machine assumed in an initial configuration of the control device on a basis of rotor position information of a rotor position sensor and an actual position of the d-axis in a rotating state of a rotor of the electric machine in dependence
of a d-voltage value describing a d-component of a stator voltage specified by the control device in the initial configuration,
of a q-voltage value describing a q-component of the stator voltage specified by the control device in the initial configuration,
of a flux value describing a magnetic flux of the rotor,
of a speed value describing the speed of the rotor in the rotating state, and
of a calibration value describing a speed-dependent voltage error of the d-component of the stator voltage, and
wherein the flux value is determined as a function of the d-voltage value and the q-volta

Assignees

• Valeo Siemens Eautomotive Germany Gmbh

Inventors

• Seilmeier Markus
• Held Andreas
• Walter Andreas
• Köpken Hans-Georg

Classifications

• H02P21/06

  Rotor flux based control involving the use of rotor position or rotor speed sensors · CPC title

• H02P21/00 Primary

  Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation · CPC title

• H02P21/14 Primary

  Estimation or adaptation of machine parameters, e.g. flux, current or voltage · CPC title

• B60L15/02

  characterised by the form of the current used in the control circuit · CPC title

• H02P27/06

  using DC to AC converters or inverters (H02P27/05 takes precedence) · CPC title