VARIABLE FREQUENCY DRIVE POWER RIDE THRU

• US 20140366546A1
• Filed: 06/13/2013
• Published: 12/18/2014
• Est. Priority Date: 06/13/2013
• Status: Active Grant

• Current Assignee: Solar Turbines Incorporated (Caterpillar Incorporated)
• Original Assignee: Solar Turbines Incorporated (Caterpillar Incorporated)
• Inventors: Bruno, Rachel, Fingleton, Daniel, Kato, Scott Hitoshi
• Granted Patent: US 9,605,597 B2
• Time in Patent Office: Days
• US Class Current: 60/772
• CPC Class Codes: F01D 21/00 Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for
• CPC Class Codes: F02C 7/268 Starting drives for the rotor , acting directly on the rotor of the gas turbine to be started
• CPC Class Codes: F02C 7/36 Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user F02C3/107 - F02C3/13 and F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H
• CPC Class Codes: F02C 9/00 Controlling gas-turbine plants; Controlling fuel supply in air- breathing jet-propulsion plants controlling air intakes F02C7/057; controlling turbines F01D; controlling compressors F04D27/00; controlling in general G05
• CPC Class Codes: F05D 2270/061 in particular the electrical frequency of driven generator
• CPC Class Codes: Y02E 20/14 Combined heat and power generation [CHP]

Abstract

A gas turbine engine includes a compressor, a combustor adjacent the compressor, a turbine adjacent the combustor, a shaft, a motor, a variable frequency drive, a stored energy source and a ride thru unit. The motor is coupled to the shaft. The variable frequency drive is electrically connected to the motor and to an AC power source. The ride thru unit electrically connects to the variable frequency drive, the AC power source and the stored energy source. The ride thru unit includes at least one DC to DC voltage converter.

Claims

1. A gas turbine engine, comprising:

a compressor including

a compressor rotor assembly including a plurality of compressor disk assemblies;

a combustor adjacent the compressor;

a turbine adjacent the combustor, the turbine including

a turbine rotor assembly including

a plurality of turbine disk assemblies;

a shaft coupled to the compressor rotor assembly and at least one turbine disk assembly;

a motor coupled to the shaft;

a variable frequency drive electrically connected to the motor and to an AC power source, the variable frequency drive including an AC to DC voltage converter and a DC to AC voltage converter;

a stored energy source; and

a ride thru unit electrically connected to the variable frequency drive, the AC power source and the stored energy source, the ride thru unit including at least one DC to DC voltage converter.

2. The gas turbine engine of claim 1, wherein the ride thru unit is configured to monitor an AC power of the AC power source, and provide power from the stored energy source to the variable frequency drive through the ride thru unit when an interruption or loss of the AC power is detected while the shaft is turned with the motor for a predetermined amount of time after shutdown of the gas turbine engine.

3. The gas turbine engine of claim 1, wherein the at least one DC to DC voltage converter is configured to convert the power from the stored energy source to 510 VDC when the AC power is detected and convert the power from the stored energy source to 560 VDC when the AC power is not detected.

4. The gas turbine engine of claim 2, wherein the predetermined amount of time is from four to five hours.

5. The gas turbine engine of claim 2, wherein the predetermined amount of time is at least four hours.

6. The gas turbine engine of claim 1, wherein the stored energy source includes a battery.

7. The gas turbine engine of claim 1, wherein the ride thru unit is electrically connected to the DC bus of the variable frequency drive.

8. The gas turbine engine of claim 2, further comprising:

a lube oil system including

a lube oil variable frequency drive;

wherein the lube oil variable frequency drive is electrically connected to the ride thru unit and the ride thru unit is further configured to provide power from the stored energy source to the lube oil variable frequency drive through the ride thru unit up to a second predetermined amount of time when an interruption or loss of the AC power is detected during operation of the gas turbine engine, and shut down the gas turbine engine when the interruption or loss of the AC power lasts longer than the second predetermined amount of time.

9. The gas turbine engine of claim 8, wherein the second predetermined amount of time is between ten and twenty seconds.

10. The gas turbine engine of claim 1, wherein the gas turbine engine includes a dual shaft configuration including the shaft and a power turbine shaft, wherein the shaft is a gas producer shaft.

11. The gas turbine engine of claim 2, further comprising:

a fuel system including

a fuel variable frequency drive;

wherein the fuel variable frequency drive is electrically connected to the ride thru unit and the ride thru unit is further configured to provide power from the stored energy source to the fuel variable frequency drive through the ride thru unit up to a second predetermined amount of time when an interruption or loss of the AC power is detected during operation of the gas turbine engine, and shut down the gas turbine engine when the interruption or loss of the AC power lasts longer than the second predetermined amount of time.

12. The gas turbine engine of claim 11, wherein the second predetermined amount of time is between three and ten seconds.

13. A gas turbine engine, comprising:

a compressor including

a compressor rotor assembly including a plurality of compressor disk assemblies;

a combustor adjacent the compressor;

a turbine adjacent the combustor, the turbine including

a turbine rotor assembly including

a plurality of turbine disk assemblies;

a shaft coupled to the compressor rotor assembly and at least one turbine disk assembly;

a starter motor coupled to the shaft configured to rotate the shaft after shutdown of the gas turbine engine;

a variable frequency drive electrically connected to the starter motor and to an alternating current power source;

a stored energy source including a battery; and

a ride thru unit electrically connected to the variable frequency drive, the stored energy source, and the alternating current power source, the ride thru unit configured to supply DC power to the variable frequency drive from the stored energy source when a loss in the alternating current power supplied to the variable frequency drive occurs while the starter motor rotates the shaft after shutdown of the gas turbine engine.

14. The gas turbine engine of claim 13, further comprising:

a lube oil pump configured to supply lube oil to bearing assemblies for the gas turbine engine;

a lube oil variable frequency drive electrically connected to the lube oil pump and the alternating current power source; and

a lube oil ride thru unit electrically connected to the lube oil variable frequency drive, the stored energy source, and the alternating current power source, the lube oil ride thru unit configured to supply power to the lube oil variable frequency drive from the stored energy source when a loss in the alternating current power supplied to the lube oil variable frequency drive occurs during operation of the gas turbine engine.

15. The gas turbine engine of claim 13, further comprising:

a fuel pump configured to supply fuel to bearing assemblies for the gas turbine engine;

a fuel variable frequency drive electrically connected to the fuel pump and the alternating current power source; and

a fuel ride thru unit electrically connected to the fuel variable frequency drive, the stored energy source, and the alternating current power source, the fuel ride thru unit configured to supply power to the fuel variable frequency drive from the stored energy source when a loss in the alternating current power supplied to the fuel variable frequency drive occurs during operation of the gas turbine engine.

16. A method for cooling down a shaft for a gas turbine engine with a slow roll, the method comprising:

turning the shaft for the gas turbine engine with a motor connected to a variable frequency drive after shutting down the gas turbine engine;

monitoring the alternating current power of an alternating current power source for the variable frequency drive with a ride thru unit while turning the shaft with the motor; and

providing power from a stored energy source to the variable frequency drive through the ride thru unit when an interruption or loss of the alternating current power occurs.

17. The method of claim 16, wherein providing power from the stored energy source to the variable frequency drive through the ride thru unit when the interruption or loss of the alternating current power occurs includes providing direct current power from at least one battery to a direct current bus of the variable frequency drive.

18. The method of claim 17, wherein turning the shaft for the gas turbine engine with the motor connected to the variable frequency drive after shutting down the gas turbine engine includes using the variable frequency drive to control the speed of the shaft.

19. The method of claim 16, wherein turning the shaft for the gas turbine engine with the motor connected to the variable frequency drive after shutting down the gas turbine engine is performed for a predetermined amount of time.

20. The method of claim 16, wherein turning the shaft for the gas turbine engine with the motor connected to the variable frequency drive after shutting down the gas turbine engine is performed until the shaft cools to a predetermined temperature.