Motor stator resistance calculation

Patent metadata

Field	Value
Publication number	US-11366147-B2
Application number	US-202017010624-A
Country	US
Kind code	B2
Filing date	Sep 2, 2020
Priority date	Sep 2, 2020
Publication date	Jun 21, 2022
Grant date	Jun 21, 2022

Abstract

For motor stator resistance calculation, a method estimates an output voltage using a Direct Current (DC) bus voltage and a duty ratio for a motor drive at a first switching frequency and at least one second switching frequency. The method measures an output current at the first switching frequency and the at least one second switching frequency. The method calculates a first stator resistance for the first switching frequency and at least one second stator resistance for the at least one second switching frequency. The method estimates a stator resistance at a DC condition based on the first stator resistance and the at least one second stator resistance. The method sets a dynamic compensation based on a stator resistance error between the first switching frequency and the at least one second switching frequency.

First claim

What is claimed is:

1. A method comprising:
estimating, by use of a processor, an estimated output voltage using a Direct Current (DC) bus voltage and a duty ratio for a motor drive at a first switching frequency and at least one second switching frequency;
measuring a measured output current at the first switching frequency and the at least one second switching frequency;
calculating a first stator resistance for the first switching frequency and at least one second stator resistance for the at least one second switching frequency;
estimating a stator resistance at a DC condition based on the first stator resistance and the at least one second stator resistance;
setting a dynamic compensation based on a stator resistance error between the first switching frequency and the at least one second switching frequency,
dynamically calculating a calculated output voltage based on the stator resistance at the DC condition and the output current; and
controlling the motor using the calculated output voltage and the dynamic compensation.

2. The method of claim 1 , wherein the stator resistance at the DC condition is estimated using a linear regression based on the first stator resistance and the at least one second stator resistance.

3. The method of claim 1 , wherein the stator resistance at the DC condition is estimated using curve fitting based on the first stator resistance and the at least one second stator resistance.

4. The method of claim 1 , wherein the stator resistance at the DC condition is estimated as

R
s

=

R
2

+

-

F
2

F
1

-

F
2

⁢

(

R
1

-

R
2

)

,

where R 1 is the first stator resistance, R 2 is a second stator resistance, F 1 is the first switching frequency, and F 2 is the second switching frequency.

5. The method of claim 1 , wherein the dynamic compensation T d is calculated as T d =T S +T ON −T OFF , wherein T S is a dynamic transition equivalent time during a gate signal transition, T ON is a switch ON delay, and T OFF is a switch OFF delay.

6. The method of claim 1 , wherein the dynamic compensation modifies gate signals for an inverter.

7. The method of claim 1 , wherein the dynamic compensation compensates for a gate voltage drop and a diode voltage drop.

8. An apparatus comprising:
a processor;
a memory storing code executable by the processor to perform:
estimating an estimated output voltage using a Direct Current (DC) bus voltage and a duty ratio for a motor drive at a first switching frequency and at least one second switching frequency;
measuring a measured output current at the first switching frequency and the at least one second switching frequency;
calculating a first stator resistance for the first switching frequency and at least one second stator resistance for the at least one second switching frequency;
estimating a stator resistance at a DC condition based on the first stator resistance and the at least one second stator resistance;
setting a dynamic compensation based on a stator resistance error between the first switching frequency and the at least one second switching frequency;
dynamically calculating a calculated output voltage based on the stator resistance at the DC condition and the output current; and
controlling the motor using the calculated output voltage and the dynamic compensation.

9. The apparatus of claim 8 , wherein the stator resistance at the DC condition is estimated using a linear regression based on the first stator resistance and the at least one second stator resistance.

10. The apparatus of claim 8 , wherein the stator resistance at the DC condition is estimated using curve fitting based on the first stator resistance and the at least one second stator resistance.

11. The apparatus of claim 8 , wherein the stator resistance at the DC condition is estimated as

R
s

=

R
2

+

-

F
2

F
1

-

F
2

⁢

(

R
1

-

R
2

)

,

where R 1 is the first stator resistance, R 2 is a second stator resistance, F 1 is the first switching frequency, and F 2 is the second switching frequency.

12. The apparatus of claim 11 , wherein the dynamic compensation T d is calculated as T d =T S +T ON −T OFF , wherein T S is a dynamic transition equivalent time during a gate signal transition, T ON is a switch ON delay, and T OFF is a switch OFF delay.

13. The apparatus of claim 8 , wherein the dynamic compensation modifies gate signals for an inverter.

14. The apparatus of claim 8 , wherein the dynamic compensation compensates for a gate voltage drop and a diode voltage drop.

15. A non-transitory computer readable storage medium having program code embodied therein, the program code readable/executable by a to perform:
estimating an output voltage using a Direct Current (DC) bus voltage;
measuring an output current at the first switching frequency and the at least one second switching frequency;
calculating a first stator resistance for the first switching frequency and at least one second stator resistance for the at least one second switching frequency;
e

Assignees

• Rockwell Automation Tech Inc

Inventors

• Wei Lixiang
• Li Bing
• Lamb Jacob

Classifications

• H02P27/06

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

• H02P23/14 Primary

  Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage · CPC title

• H02P21/14

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

• G01R31/346

  Testing of armature or field windings · CPC title

• G01R27/08 Primary

  Measuring resistance by measuring both voltage and current · CPC title