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A control method comprises determining wheel creep of a wheel operably coupled to a traction motor and limiting a rate of change of an excitation frequency applied to the traction motor to drive the wheel, based on the determined wheel creep. According to one aspect, the rate of change of the excita

A control method comprises determining wheel creep of a wheel operably coupled to a traction motor and limiting a rate of change of an excitation frequency applied to the traction motor to drive the wheel, based on the determined wheel creep. According to one aspect, the rate of change of the excitation frequency is limited if the wheel creep exceeds a wheel creep threshold.

대표청구항 ▼

1. A control method comprising: determining, by a creep module that includes electronic hardware, wheel creep of a wheel operably coupled to a traction motor;comparing, by one or more control modules that includes electronic hardware, the wheel creep to an upper wheel creep threshold, the upper whee

1. A control method comprising: determining, by a creep module that includes electronic hardware, wheel creep of a wheel operably coupled to a traction motor;comparing, by one or more control modules that includes electronic hardware, the wheel creep to an upper wheel creep threshold, the upper wheel creep threshold based on a speed at which a vehicle that includes the wheel and the traction motor is moving;determining a limit on a rate of change of an excitation frequency of current that is applied to the traction motor to drive the wheel; andresponsive to the wheel creep exceeding the upper wheel creep threshold, limiting, by the one or more control modules, the rate of change of the excitation frequency of the current that is applied to the traction motor to drive the wheel based on the wheel creep that is determined and the limit on the rate of change that is determined. 2. The method of claim 1, wherein the rate of change of the excitation frequency is limited to a first rate of change value that is less than a second rate of change value sought to be applied to the traction motor by the one or more control modules according to the wheel creep, the one or more control modules comprising at least one of a creep regulator or a torque regulator having electronic hardware. 3. The method of claim 1, wherein the wheel creep is determined by the one or more control modules at least in part based on a speed of the traction motor. 4. The method of claim 1, wherein limiting the rate of change of the excitation frequency by the one or more control modules limits wheel creep gain of the wheel. 5. The method of claim 4, wherein the wheel creep gain is limited by the one or more control modules to no more than 1.61 kilometers per hour, per second. 6. The method of claim 1, wherein the rate of change is limited by the one or more control modules to limit wheel creep gain of the wheel to no more than 1.61 kilometers per hour, per second. 7. The method of claim 1, wherein determining the wheel creep by the creep module and limiting the rate of change of the excitation frequency by the one or more control modules are carried out independently for each of plural wheels and traction motor pairs of the vehicle. 8. The method of claim 1, wherein determining the wheel creep and limiting the rate of change of the excitation frequency are carried out by one or more electronic hardware control modules that includes the creep module and the one or more control modules and that is configured to generate signals for controlling a traction inverter to power the traction motor. 9. The method of claim 1, wherein the rate of change of the excitation frequency is limited by the one or more control modules when one or more of a speed of the wheel or the speed of a vehicle is below a designated value. 10. The control method of claim 1, further comprising stopping the limiting of the rate of change of the excitation frequency of the current responsive to the one or more control modules determining that the wheel creep decreased below a lower wheel creep threshold. 11. The control module of claim 1, further comprising automatically applying a friction modifying substance to a route being traveled by the vehicle by a substance applicator onboard the vehicle responsive to the wheel creep increasing to within a designated amount of the upper wheel creep threshold during the one or more control modules limiting the rate of change of the excitation frequency of the current. 12. A control method comprising: monitoring wheel creep of a wheel operably coupled to a traction motor;determining, by one or more control modules that includes electronic hardware, whether the wheel creep exceeds an upper wheel creep threshold, wherein the upper wheel creep threshold changes based on a speed of a vehicle that includes the wheel and the traction motor;determining a limit on a rate of change of excitation frequency of a current applied to the traction motor; andlimiting, by the one or more control modules, the rate of change of the excitation frequency of the current applied to the traction motor to drive the wheel responsive to the wheel creep exceeding the upper wheel creep threshold and based on the limit of the rate of change that is determined. 13. The control method of claim 12, further comprising applying the current at the excitation frequency to the traction motor to drive the wheel, wherein limiting the rate of change of the excitation frequency by the one or more control modules includes restricting the rate at which the excitation frequency can change responsive to the wheel creep of the wheel exceeding the upper wheel creep threshold. 14. The control method of claim 12, further comprising applying the current to the traction motor at the excitation frequency by an inverter and monitoring the wheel creep of the wheel. 15. A control method comprising: determining a wheel creep of a wheel driven by a traction motor;determining, by one or more control modules that includes electronic hardware, whether the wheel creep of the wheel driven by the traction motor has accelerated away from a creep setpoint by at least a threshold, wherein the creep setpoint changes based on changes in a speed at which a vehicle that includes the wheel and the traction motor moves;determining a limit on a rate of change of an excitation frequency of a current that is applied to the traction motor to drive the wheel; andcontrolling, by the one or more control modules, the excitation frequency of the current applied to the traction motor to reduce accelerating torque delivered by the motor to the wheel responsive to the wheel accelerating away from the creep setpoint by at least the threshold and based on the limit on the rate of change that is determined. 16. The method of claim 15, wherein controlling the excitation frequency comprises limiting, by the one or more control modules, the rate of change of the excitation frequency. 17. A control system comprising: a first control module that includes one or more processors configured to generate an excitation frequency of a current supplied to a traction motor of a traction motor system, based at least in part on a throttle command and a speed associated with one of the traction motor or a wheel driven by the traction motor; anda second control module that includes one or more processors configured to communicate with the first control module and to determine a wheel creep of the wheel driven by the traction motor, compare the wheel creep to an upper wheel creep threshold, determine a limit on a rate of change of the excitation frequency of the current that is supplied to the traction motor, and limit the rate of change of the excitation frequency responsive to a wheel creep of the wheel exceeding the upper wheel creep threshold and based on the limit on the rate of change, wherein the upper wheel creep threshold changes based on changes in a speed at which a vehicle that includes the wheel and the traction motor moves. 18. The system of claim 17, wherein the second control module is configured to limit the rate of change of the excitation frequency to a first rate of change value that is less than a second rate of change value sought to be applied to the traction motor by the first control module according to the wheel creep. 19. The system of claim 17, wherein the second control module is configured to limit the rate of change of the excitation frequency in order to limit wheel creep gain of the wheel. 20. The system of claim 17, wherein the first control module is configured to determine the wheel creep and the second control module is configured to limit the rate of change of the excitation frequency independently for each of a plurality of wheel and traction motor pairs of the vehicle. 21. The system of claim 17, wherein the second control module is configured to limit the rate of change of the excitation frequency responsive to one or more of a speed of the wheel or a speed of the vehicle being below a designated value. 22. The control system of claim 17, wherein the second control module also is configured to stop limiting of the rate of change of the excitation frequency of the current responsive to the wheel creep decreasing below a lower wheel creep threshold. 23. The control system of claim 17, further comprising a friction modifying system including a substance applicator configured to automatically apply a friction modifying substance to a route being traveled by the vehicle responsive to the wheel creep increasing to within a designated amount of the upper wheel creep threshold as the second control module limits the rate of change of the excitation frequency of the current.