RESISTIVE TORSIONAL MODE DAMPING SYSTEM AND METHOD

• US 20070279012A1
• Filed: 05/05/2006
• Published: 12/06/2007
• Est. Priority Date: 05/05/2006
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Sihler, Christof
• Granted Patent: US 7,423,411 B2
• Time in Patent Office: Days
• US Class Current: 322/20
• CPC Class Codes: H02P 23/04 specially adapted for damping motor oscillations, e.g. for reducing hunting

Abstract

A resistive torsional mode damping system for a shaft of a machine includes: a sensor configured for sensing a signal representative of torque on the shaft; a controller configured for using the sensed signal for detecting a presence of a torsional vibration on the shaft corresponding to a natural frequency of the shaft and for generating control signals for damping the torsional vibration; and a damper including a damping converter and resistor coupled to a DC output of the damping converter, the damping converter being coupled to the machine through a power bus and having a power rating on the order of less than or equal to about five percent of a nominal power of the machine.

Claims

1. A resistive torsional mode damping system for a shaft of a machine, the system comprising:

a sensor configured for sensing a signal representative of torque on the shaft;

a controller configured for using the sensed signal for detecting a presence of a torsional vibration on the shaft corresponding to a natural frequency of the shaft and for generating control signals for damping the torsional vibration;

a damper comprising a damping converter and a resistor coupled to a DC output of the damping converter, the damping converter being coupled to the machine through a power bus and having a power rating on the order of less than or equal to about five percent of a nominal power of the machine.

2. The damping system of claim 1, further comprising a pulse width modulated (PWM) element coupled in series with the resistor and configured for receiving the control signals, wherein the damping converter comprises a diode rectifier.

3. The damping system of claim 2 wherein the PWM element comprises an insulated gate bipolar transistor or an integrated gate commutated thyristor.

4. The damping system of claim 2, further comprising a capacitor coupled in parallel with the combination of the resistor and the PWM element.

5. The damping system of claim 4 wherein the damping system is configured for energy dissipation but not for energy storage.

6. The damping system of claim 2 further comprising an additional sensor for obtaining a parameter representative of a voltage or a current across the resistor.

7. The damping system of claim 6 wherein the controller comprises a band pass filter for passing sensor signals at a frequency corresponding to the natural mode, a phase shifter for adjusting the phase shift of each filtered signal to the correct value, and a gain element for controlling the magnitude of the adjusted signal.

8. The damping system of claim 7 wherein the controller further comprises a limiter for limiting the controlled adjusted signal, a low pass filter for filtering the parameter, a difference element for obtaining the difference between the limited signal and the filtered parameter, and a PWM control element for generating the control signals.

9. The damping system of claim 1 wherein the machine comprises a motor.

10. The damping system of claim 9 wherein the damping converter comprises a thyristor rectifier.

11. The damping system of claim 9 wherein the damping converter comprises an IGBT rectifier.

12. The damping system of claim 1 wherein the controller comprises a bandpass filter for passing sensor signals at a frequency corresponding to the natural mode, a phase shifter for adjusting the phase shift of each filtered signal to the correct value, and a gain element for controlling the magnitude of the adjusted signal.

13. The damping system of claim 1 wherein the machine comprises a generator.

14. The damping system of claim 1 embodied within an electric-motor driven compressor, a wind turbine, or a manufacturing line.

15. The damping system of claim 1 wherein the damper comprises a plurality of dampers each comprising a respective damping converter and a respective resistor coupled to the DC output of the respective damping converter, each respective damping converter being coupled to the machine through the power bus and having a power rating on the order of less than or equal to about five percent of a nominal power of the machine.

16. The damping system of claim 15 wherein at least two of the plurality of dampers are identical.

17. The damping system of claim 1 wherein damping converter 22 comprises a discrete damping converter.

18. A resistive torsional mode damping method for a shaft of a machine, the method comprising:

sensing a signal representative of torque on the shaft;

using the sensed signal for detecting a presence of a torsional vibration on the shaft corresponding to a natural frequency of the shaft and for generating control signals for damping the torsional vibration;

providing the control signals to a damper comprising a damping converter and a resistor coupled to a DC output of the damping converter, wherein the damping converter is coupled to the machine through a power bus and has a power rating on the order of less than or equal to about five percent of a nominal power of the machine.

19. The damping method of claim 18 wherein the damper further comprises a pulse width modulated (PWM) element coupled in series with the resistor, and wherein providing the control signals comprises providing the control signals to the PWM element.

20. The damping method of claim 18 wherein the damping converter comprises an active rectifier, and wherein providing the control signals comprises providing the control signals to switches of the rectifier.

21. A resistive torsional mode damping system for a shaft of a wind turbine, the system comprising:

a sensor configured for sensing a signal representative of torque on the shaft of the wind turbine;

a controller configured for using the sensed signal for detecting a presence of a torsional vibration on the shaft corresponding to a natural frequency of the shaft and for generating control signals for damping the torsional vibration;

a damper comprising a diode rectifier coupled to the machine through a power bus and having a power rating on the order of less than or equal to about five percent of a nominal power of the machine, a resistor coupled to a DC output of the diode rectifier, and a pulse width modulated (PWM) element coupled in series with the resistor and configured for receiving the control signals.