Monitoring health of electrical equipment

• US 10,256,761 B2
• Filed: 08/31/2016
• Issued: 04/09/2019
• Est. Priority Date: 08/31/2016
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Tran Van, Hoang, Chin, Siew Wen, Adenwala, Fatema S., Narkhede, Ravindra V.
• Primary Examiner(s): Santana, Eduardo Colon
• Assistant Examiner(s): Bouziane, Said
• Application Number:
  US15/253,041
• Publication Number:
  US 20180062553A1
• Time in Patent Office: 951 Days
• CPC Class Codes: H02P 23/14 Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage
• CPC Class Codes: H02P 29/024 Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load
• CPC Class Codes: H02P 29/0241 the fault being an overvoltage

Abstract

Techniques for monitoring the health of a device comprising a motor or generator are described. An apparatus to monitor the health of the device includes a plurality of sensors to detect root-mean-square (RMS) current values for a plurality of stator windings of the device. The apparatus also includes a processor to receive the RMS current values from the plurality of sensors and compute a fault indicator based on the RMS current values. The fault indicator represents a level of current imbalance between the plurality of stator windings due to winding faults.

Claims

1. A device comprising a motor or generator and an apparatus to monitor the health of the device, comprising:

a plurality of stator windings of the device;

a plurality of sensors to detect root-mean-square (RMS) current values for each of the plurality of stator windings of the device; and

a processor to;

receive the RMS current values from the plurality of sensors;

convert the RMS current values to peak current values;

determine a modified direct current, Id, and a modified quadrature current, Iq, based on the peak current values and referencing a phase angle of 120 degrees in place of an actual measured phase angle;

compute a fault indicator based on the modified direct current, Id, and the modified quadrature current, Iq, wherein the fault indicator represents a level of current imbalance between the plurality of stator windings due to winding faults; and

transmit the fault indicator to a display device.

2. The apparatus of claim 1, wherein the device comprises three stator windings and the plurality of sensors comprises three sensors to detect the RMS current values for each of the three stator windings.

3. The apparatus of claim 1, wherein the device is a motor and the RMS current values are detected periodically at a sampling rate that is lower than the frequency of an AC current driving the motor.

4. The apparatus of claim 1, wherein the plurality of stator windings comprises a first stator winding, a second stator winding, and a third stator winding, and the fault indicator, R, is computed according to the following formula:

5. The apparatus of claim 1, wherein the health of the device is to be displayed as a circle with a radius equal to or proportional to the fault indicator.

6. The apparatus of claim 1, wherein the health of the device is to be displayed as a rectangular plot of a magnitude of the fault indicator against time.

7. The apparatus of claim 1, wherein the apparatus is an IoT device configured to wirelessly couple to a communications network.

8. The apparatus of claim 1, wherein the apparatus is an IoT component of a fog device comprising a plurality of health monitors each monitoring a separate device.

9. A method of monitoring the health of a motor, comprising:

generating AC drive currents and delivering the drive currents to a plurality of stator windings of the motor to drive the motor at a specified motor speed;

receiving root-mean-square (RMS) current values from a plurality of sensors, wherein each RMS current value represents an RMS current on each of the plurality of stator windings;

converting the RMS current values to peak current values;

determining a modified direct current, Id, and a modified quadrature current, Iq, based on the peak current values and referencing a phase angle of 120 degrees in place of an actual measured phase angle;

computing a fault indicator based on the modified direct current, Id, and the modified quadrature current, Iq, wherein the fault indicator represents a level of current imbalance between the plurality of stator windings due to winding faults; and

transmitting the fault indicator to a display device.

10. The method of claim 9, wherein receiving the RMS current values comprises receiving the RMS current values from three sensors to detect the RMS current values for each of three stator windings.

11. The method of claim 9, wherein receiving the RMS current values comprises receiving the RMS current values periodically at a sampling rate that is lower than the frequency of the AC drive current.

12. The method of claim 9, wherein the plurality of stator windings comprises a first stator winding, a second stator winding, and a third stator winding, and computing the fault indicator, R, comprises computing the fault indicator according to the following formula:

13. The method of claim 9, comprising transmitting the fault indicator to a health monitoring station, wherein the fault indicator is to be displayed at the health monitoring station as a circle with a radius equal to or proportional to the fault indicator.

14. The method of claim 9, comprising transmitting the fault indicator to a health monitoring station, wherein the fault indicator is to be displayed at the health monitoring station as a rectangular plot of a magnitude of the fault indicator against time.

15. The method of claim 9, comprising wirelessly transmitting the fault indicator to an IoT device.

16. The method of claim 9, comprising wirelessly transmitting the fault indicator to an IoT device which is an IoT component of a fog device comprising a plurality of health monitors each monitoring a separate motor.

17. A tangible, non-transitory, computer-readable medium comprising instructions that, when executed by a processor, direct the processor to operate a health monitor for a device comprising a motor or generator, the instructions to direct the processor to:

detect root-mean-square (RMS) current values for a plurality of stator windings of the device;

convert the RMS current values to peak current values;

determine a modified direct current, Id, and a modified quadrature current, Iq, based on the peak current values and referencing a phase angle of 120 degrees in place of an actual measured phase angle;

compute a fault indicator based on the modified direct current, Id, and the modified quadrature current, Iq, wherein the fault indicator represents a level of current imbalance between the plurality of stator windings due to winding faults; and

transmit the fault indicator to a display device.

18. The computer-readable medium of claim 17, wherein the device is a motor and the processor is to detect the RMS current values periodically at a sampling rate that is lower than a frequency of an AC current driving the motor.

19. The computer-readable medium of claim 17, wherein the plurality of stator windings comprises a first stator winding, a second stator winding, and a third stator winding, and the processor is to compute the fault indicator, R, according to the following formula: