Method and system for control of turbogenerator power and temperature

• US 20040245783A1
• Filed: 07/09/2004
• Published: 12/09/2004
• Est. Priority Date: 04/02/1998
• Status: Active Grant

• Current Assignee: Capstone Turbine Corp.
• Original Assignee: Capstone Turbine Corp.
• Inventors: Wacknov, Joel, Gilbreth, Mark, Wall, Simon
• Granted Patent: US 6,958,550 B2
• Time in Patent Office: Days
• US Class Current: 290/52
• CPC Class Codes: H02J 1/10 Parallel operation of dc sources
• CPC Class Codes: H02J 1/14 Balancing the load in a network

Abstract

A power controller controls the turbine of a turbine powered generating system regardless of the load on the system to maximize the efficiency of the turbine and maintains the turbine at a substantially constant temperature during a system load change by using an energy storage device to provide power to the load while the turbine is changing speed to meet the new load demand.

Claims

1. A method of controlling a turbine of a turbine powered generating system regardless of the load on the system, to maximize the efficiency of the turbine, the system further including an electrical generator, and a storage device, the method comprising:

maintaining an exhaust gas temperature substantially constant;

using the electrical generator to satisfy a first power demand on the system until the system is required to satisfy an additional power demand;

when the additional power is demanded, temporarily using the storage device to satisfy the additional power demand and at least a portion of the first power demand;

increasing the speed of the turbine from the speed required to satisfy the first power demand to a higher speed required to satisfy the first power demand and the additional power demand; and

once the higher speed is achieved, using the electrical generator to satisfy both the first power demand and the additional power demand.

2. The method as set forth in claim 1, wherein the substantially constant exhaust gas temperature is at or near the maximum design temperature of the turbine.

3. The method of claim 1, wherein the external storage device is used to temporarily satisfy all of the additional power demand and the first power demand.

4. A method of controlling a turbine of a turbine powered generating system, regardless of the load on the system, to maximize the efficiency of the turbine, the system further including an electrical generator, and a storage device, the method comprising:

maintaining an exhaust gas of the turbine at a substantially constant temperature;

using the electrical generator to satisfy a first power demand on the system until the system is required to satisfy a lower power demand;

when the lower power is demanded, temporarily increasing the first power demand on the generator and temporarily using the storage device to absorb the additional power demand and at least a portion of the first power demand;

decreasing the speed of the turbine from the speed required to satisfy the first power demand to a lower speed required to satisfy the lower power demand; and

once the lower speed is achieved, using the electrical generator to satisfy the lower power demand.

5. A method as set forth in claim 4, wherein the constant exhaust temperature is at or near the maximum design temperature of the turbine.

6. A turbine powered generating system comprising:

a turbine having a predetermined maximum exhaust gas temperature;

a generator coupled to the turbine and capable of supplying a first power demand on the system;

an energy storage device capable of supplying the first power demand on the system; and

a controller, coupled to both the storage device and the turbine, for maintaining an exhaust gas temperature at or near the maximum exhaust gas temperature, the controller, in response to an additional power demand on the system, causing the energy storage device to satisfy the additional power demand and at least a portion of the first power demand, to allow the speed of the turbine to increase to a higher speed at which the generator can satisfy the additional power demand and the first power demand.

7. The generating system of claim 6, wherein the controller causes the additional power demand and the first power demand to be shifted to the generator when the turbine reaches the higher speed.

8. The generating system of claim 6, wherein the controller, in response to the additional power demand, causes the energy storage device to temporarily supply all of the first power demand and the additional power demand.

9. The generating system of claim 6, wherein the storage device is selected from the group including a battery, a flywheel, a capacitor and a power grid.

10. The generating system of claim 9, wherein the storage device is a battery and the battery is sized to supply the maximum power demand on the system.

11. The generating system of claim 6, wherein the turbine is a microturbine.

12. The generating system of claim 11, wherein the microturbine is a recuperated microturbine.

13. The generating system of claim 6, wherein the controller includes means, in response to a lower power demand on the system, for causing the first power demand on the generator to be temporarily increased and temporarily absorbed by the energy storage device.

14. The generating system of claim 13, wherein the controller shifts the lower power demand to the generator when the turbine has decelerated to the speed required to satisfy the lower power demand.

15. A turbine powered generating system comprising:

a turbine having a predetermined maximum exhaust gas temperature;

a generator coupled to the turbine and capable of supplying a first power demand on the system;

an energy storage device capable of temporarily absorbing at least a portion of the first power demand on the system; and

a controller, coupled to both the storage device and the turbine, for maintaining an exhaust gas temperature at or near the maximum exhaust gas temperature, the controller including means, in response to a decreased power demand on the system, for temporarily causing an additional power demand on the generator and for causing the additional power demand and at least a portion of the first power demand to be shifted to the energy storage device to allow the speed of the turbine to decrease to a lower speed, where the generator can supply the decreased power demand.

16. Apparatus for controlling a turbine power generation system, the apparatus being responsive to a load demand during operation, the apparatus comprising:

a turbine;

an electric generator coupled to the turbine;

an energy storage device;

a controller including means for monitoring the speed of the turbine and an exhaust gas temperature, the controller further including means for determining whether to shift any of the load demand from the generator to the energy storage device when the load demand changes; and

means, responsive to the controller, for regulating fuel flow to the turbine to hold the exhaust gas temperature substantially constant, even when the load demand changes.

17. The apparatus of claim 16, wherein the controller causes the regulating means to hold the temperature of the exhaust gas temperature substantially constant, independent of turbine speed.

18. The apparatus of claim 16, wherein turbine speed is controlled by regulating a load on the generator in order to maintain a speed set point.

19. The apparatus of claim 18, wherein the turbine speed set point is determined by the load demand and achieved by controlling the generator load independent of the load demand.

20. The apparatus of claim 18, wherein the controller causes the generator load to increase when the turbine speed increases above the speed set point.