Systems and methods for motor drive cable characteristics identification and compensation therefor

Patent metadata

Field	Value
Publication number	US-2019393822-A1
Application number	US-201816019222-A
Country	US
Kind code	A1
Filing date	Jun 26, 2018
Priority date	Jun 26, 2018
Publication date	Dec 26, 2019
Grant date	—

Abstract

A motor drive system includes at least one current sensor disposed within a housing of the motor drive system. The at least one sensor is configured to detect a current of output power produced by the motor drive system. The motor drive system also includes a controller configured to determine a resonant frequency of a cable connected to the motor drive system based at least in part on the detected current, and to adjust pulse width modulation (PWM) switching of the motor drive system based at least in part on the determined resonant frequency of the cable.

First claim

1 . A motor drive system comprising:
at least one current sensor disposed within a housing of the motor drive system, wherein the at least one current sensor is configured to detect a current of output power produced by the motor drive system; and a controller configured to determine a resonant frequency of a cable connected to the motor drive system based at least in part on the detected current.

2 . The motor drive system of claim 1 , wherein the controller is disposed within the housing of the motor drive system.

3 . The motor drive system of claim 1 , wherein the controller is configured to adjust pulse width modulation (PWM) switching of the motor drive system based at least in part on the determined resonant frequency of the cable.

4 . The motor drive system of claim 3 , wherein the controller is configured to adjust the PWM switching of the motor drive system to compensate for transmission delay through the cable.

5 . The motor drive system of claim 3 , wherein the controller is configured to adjust the PWM switching of the motor drive system to compensate for dead time relating to the PWM switching.

6 . The motor drive system of claim 3 , wherein the controller is configured to determine a plurality of modulation index (MI) values based on the determined resonant frequency of the cable.

7 . The motor drive system of claim 6 , wherein the controller is configured to adjust the PWM switching of the motor drive system based on a comparison of a PWM carrier wave and the plurality of MI values for each cycle of the PWM carrier wave.

8 . The motor drive system of claim 6 , wherein the plurality of MI values comprises a first MI value corresponding to a frequency of a PWM carrier wave, a second MI value equal to 1, and a third MI value corresponding to the determined resonant frequency of the cable.

9 . The motor drive system of claim 1 , wherein the controller is configured to determine the resonant frequency of the cable during a start-up test of the motor drive system.

10 . A method comprising:
detecting, via at least one current sensor of a motor drive system, a current of output power produced by the motor drive system; and determining, via a controller of the motor drive system, a resonant frequency of a cable connected to the motor drive system based at least in part on the detected current.

11 . The method of claim 10 , comprising adjusting, via the controller of the motor drive system, pulse width modulation (PWM) switching of the motor drive system based at least in part on the determined resonant frequency of the cable.

12 . The method of claim 11 , comprising adjusting, via the controller of the motor drive system, the PWM switching of the motor drive system to compensate for transmission delay through the cable.

13 . The method of claim 11 , comprising adjusting, via the controller of the motor drive system, the PWM switching of the motor drive system to compensate for dead time relating to the PWM switching.

14 . The method of claim 11 , comprising determining, via the controller of the motor drive system, a plurality of modulation index (MI) values based on the determined resonant frequency of the cable.

15 . The method of claim 14 , comprising adjusting, via the controller of the motor drive system, the PWM switching of the motor drive system based on a comparison of a PWM carrier wave and the plurality of MI values for each cycle of the PWM carrier wave.

16 . The method of claim 14 , wherein the plurality of MI values comprises a first MI value corresponding to a frequency of a PWM carrier wave, a second MI value equal to 1, and a third MI value corresponding to the determined resonant frequency of the cable.

17 . The method of claim 10 , comprising determining, via the controller of the motor drive system, the resonant frequency of the cable during a start-up test of the motor drive system.

18 . A method comprising:
detecting, via at least one current sensor of a motor drive system, a current of output power produced by the motor drive system; determining, via a controller of the motor drive system, a resonant frequency of a cable connected to the motor drive system based at least in part on the detected current; and adjusting, via the controller of the motor drive system, pulse width modulation (PWM) switching of the motor drive system based at least in part on the determined resonant frequency of the cable.

19 . The method of claim 18 , comprising determining, via the controller of the motor drive system, a plurality of modulation index (MI) values based on the determined resonant frequency of the cable.

20 . The method of claim 19 , comprising adjusting, via the controller of the motor drive system, the PWM switching of the motor drive system based on a comparison of a PWM carrier wave and the plurality of MI values for each cycle of the PWM carrier wave.

21 . The method of claim 19 , wherein the plurality of MI values comprises a first MI value corresponding to a frequency of a PWM carrier wave, a second MI value equal to 1, and a third MI value corresponding to the determined resonant frequency of the cable.

Assignees

• Rockwell Automation Tech Inc

Inventors

• Ganesan Nandini
• Tallam Rangarajan M

Classifications

• H02P31/00

  Arrangements for regulating or controlling electric motors not provided for in groups H02P1/00 - H02P5/00, H02P7/00 or H02P21/00 - H02P29/00 · CPC title

• H02P27/08 Primary

  with pulse width modulation · CPC title

• H02K11/27

  Devices for sensing current, or actuated thereby (overcurrent protection responsive to temperature of the machines or parts thereof, e.g. windings, H02K11/25) · CPC title