Managing wheel slip in a locomotive

• US 20050206230A1
• Filed: 02/16/2005
• Published: 09/22/2005
• Est. Priority Date: 02/17/2004
• Status: Active Grant

• Current Assignee: Railpower, LLC
• Original Assignee: Railpower Technologies Corp.
• Inventors: Donnelly, Frank Wegner
• Granted Patent: US 7,467,830 B2
• Time in Patent Office: Days
• US Class Current: 303/139
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 2240/70 Interactions with external data bases, e.g. traffic centres
• CPC Class Codes: B60L 2260/46 by self learning
• CPC Class Codes: B60L 3/102 of individual wheels
• CPC Class Codes: B60T 8/1705 for rail vehicles
• CPC Class Codes: B61C 15/08 Preventing wheel slippage adjusting wheel-braking force to prevent wheel slippage B60T8/00 ; removing undesirable matter from the permanent way of railways E01H8/00
• CPC Class Codes: B61C 15/12 by reducing the driving power
• CPC Class Codes: B61C 15/14 controlling distribution of tractive effort between driving wheels
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility
• CPC Class Codes: Y02T 30/00 Transportation of goods or passengers via railways, e.g. energy recovery or reducing air resistance
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles

Abstract

The present invention is directed to the termination of the occurrence of wheel slip/skid and prediction and prevention of the onset of wheel slip/skid in a locomotive. In one configuration, a lookup table of adhesion factors is used to predict the occurrence of wheel slip/skid.

Claims

1. A method, comprising:

determining that at least one wheel corresponding to a first traction motor is experiencing wheel slip, wherein the first traction motor is one of a plurality of traction motors, each of the plurality of traction motors being independently coupled to and driving at least one wheel; and

in response to the determining step, incrementally reducing power supplied to the first traction motor for a selected period of time while continuing to provide power in excess of the reduced power to at least one other of the plurality of traction motors, wherein, during the reducing step, the reduced power continues to drive the at least one wheel experiencing wheel slip.

2. The method of claim 1, wherein the power is supplied to the first traction motor by a waveform, wherein at least one of the amplitude, pulse width and frequency of the waveform is incrementally reduced, and wherein, after each incremental power reduction, the reduced power is maintained for a predetermined time interval to determine whether wheel slip has been reduced to a predetermined acceptable level as a result of the respective incremental power reduction.

3. The method of claim 2, wherein, upon the detection of a predetermined acceptable level of wheel slippage, the reduced power is not further reduced and wherein the at least one of the amplitude, pulse width and frequency of the waveform supplied to the first traction motor is different from the at least one of the amplitude, pulse width and frequency of the waveform supplied to the at least one other of the plurality of traction motors over the selected time period.

4. The method of claim 1, wherein the determining step comprises the substep of:

detecting an operating characteristic of each of the plurality of traction motors and/or at least one wheel driven by each of the plurality of traction motors; and

wherein the operating characteristic is at least one of (i) an operating armature rotational speed of the corresponding traction motor and/or at least a rotational speed of one wheel driven by the corresponding traction motor and (ii) a corresponding electrical current supplied to each of the plurality of traction motors, and wherein the determining step comprises;

determining that the operating characteristic of the first traction motor has a predetermined relationship with an operating characteristic setpoint; and

further comprising;

comparing a detected operating characteristic detected for each of the traction motors to the operating characteristic setpoint and wherein, when the detected operating characteristic has the predetermined relationship with the operating characteristic setpoint, the at least one wheel of the corresponding traction motor is determined to be experiencing wheel slippage.

5. The method of claim 4, wherein the reducing step is performed until the detected operating characteristic for the first traction motor no longer has the predetermined relationship with the operating characteristic setpoint.

6. The method of claim 1, further comprising:

detecting a corresponding electrical current supplied to each of the plurality of traction motors, and wherein the determining step comprises;

determining that the electrical current and/or electrical current time derivative corresponding to the first traction motor has decreased, wherein, when the decrease is abrupt, at least one wheel of the first traction motor is determined to be experiencing wheel slip.

7. The method of claim 1, wherein the determining step comprises the substep of:

detecting an operating speed of at least one wheel driven by each of the traction motors; and

detecting a speed of a locomotive comprising the plurality of traction motors and wherein, when the speed of a wheel exceeds the locomotive speed, the wheel is determined to be experiencing wheel slip.

8. The method of claim 1, wherein the determining step comprises the substep of:

detecting an operating characteristic of each of the plurality of traction motors and/or at least one wheel driven by each of the plurality of traction motors; and

wherein the operating characteristic is an operating speed of at least one wheel driven by the corresponding traction motor; and

detecting a speed of a locomotive comprising the plurality of traction motors and wherein, when the speed of a wheel exceeds the locomotive speed, the wheel is determined to be experiencing wheel slippage.

9. The method of claim 1, wherein the determining step comprises the substep of:

detecting a corresponding revolutions-per-minute (RPMs) of each of the plurality of traction motors, and wherein the determining step comprises;

determining that the RPMs of the first traction motor have increased, wherein, when the increase is abrupt, at least one wheel of the first traction motor is determined to be experiencing wheel slip.

10. The method of claim 1, wherein the determining step comprises the substep of:

sampling a frequency spectrum of a plurality of historic current values provided to a selected traction motor; and

identifying, from the sampled frequency spectrum, a frequency response that is characteristic of the occurrence of wheel slip.

11. A locomotive, comprising:

a plurality of traction motors, each of the plurality of traction motors being independently coupled to and driving at least one wheel;

a plurality of sensors operable to sense an operating characteristic, wherein each of the sensors corresponds to a traction motor; and

a controller operable to (a) determine, based on the sensed operating characteristic, that at least one wheel corresponding to a first traction motor is experiencing wheel slippage and (b) in response thereto incrementally reduce power supplied to the first traction motor for a selected period of time while continuing to provide power in excess of the reduced power to at least one other of the plurality of traction motors, wherein the reduced power continues to drive the at least one wheel experiencing wheel slippage.

12. The locomotive of claim 11, wherein the controller is further operable to compare the detected operating characteristic detected for each of the traction motors to an operating characteristic set point and, when the detected operating characteristic for any traction motor traverses to the undesirable side of the operating characteristic set point, the controller determines that the at least one wheel of the corresponding traction motor is experiencing wheel slippage.

13. The locomotive of claim 11, wherein the power is supplied to the first traction motor in a series of pulses, wherein at least one of the amplitude, pulse width and pulse spacing of the pulses is incrementally reduced, and wherein, after each incremental power reduction, the reduced power is maintained for a predetermined time interval to determine whether wheel slippage has been reduced to a predetermined acceptable level as a result of the respective incremental power reduction.

14. The locomotive of claim 13, wherein, upon the detection of a predetermined acceptable level of wheel slippage, the reduced power is not further reduced and wherein the at least one of the amplitude, pulse width and pulse spacing of the pulses supplied to the first traction motor is different from the at least one of the amplitude, pulse width and pulse spacing of the pulses supplied to the at least one other of the plurality of traction motors over the selected time period.

15. The locomotive of claim 11, wherein the sensed operating characteristic is a corresponding electrical current supplied to each of the plurality of traction motors, and wherein the determining operation includes the sub-operations of:

determining that the electrical current and/or electrical current time derivative corresponding to the first traction motor has decreased, wherein, when the decrease is abrupt, the controller determines that at least one wheel of the first traction motor is experiencing wheel slip.

16. The locomotive of claim 11, wherein the sensed operating characteristic is an operating speed of at least one wheel driven by each of the traction motors and wherein the controller is further operable to detect a speed of the locomotive and wherein, when the speed of a wheel exceeds the locomotive speed, the controller determines that the wheel is experiencing wheel slip.

17. The locomotive of claim 11, wherein the operating characteristic is an operating speed of at least one wheel driven by a corresponding traction motor and wherein, when the speed of a wheel exceeds the locomotive speed, the controller determines that the wheel is experiencing wheel slippage.

18. The locomotive of claim 11, wherein the sensed operating characteristic is a corresponding revolutions-per-minute (RPMs) of each of the plurality of traction motors, and wherein, when an increase in the RPMs is abrupt, the controller determines that at least one wheel of the first traction motor is experiencing wheel slip.

19. The locomotive of claim 11, with a the plurality of traction motors and further comprising:

a prime energy source;

an energy conversion device, in communication with the prime energy source, to convert the energy output by the prime energy source into direct current electricity;

an energy storage device, in communication with the energy conversion device and the plurality of traction motors, to receive and store direct current electricity;

a plurality of power control circuits corresponding to the plurality of traction motors.