Microturbine/capacitor power distribution system

• US 6,639,328 B2
• Filed: 12/19/2001
• Issued: 10/28/2003
• Est. Priority Date: 12/19/2000
• Status: Active Grant

• Current Assignee: Capstone Turbine Corp.
• Original Assignee: Capstone Turbine Corp.
• Inventors: Wacknov, Joel
• Primary Examiner(s): Ponomarenko, Nicholas
• Application Number:
  US10/033,826
• Publication Number:
  US 20020195821A1
• Time in Patent Office: 678 Days
• Field of Search: 290/7, 290/52, 322/37, 322/28, 606/49
• US Class Current: 290/52
• CPC Class Codes: F01D 15/10 Adaptations for driving, or combinations with, electric generators
• CPC Class Codes: F02C 7/08 Heating air supply before combustion, e.g. by exhaust gases
• CPC Class Codes: F02C 9/28 Regulating systems responsive to plant or ambient parameters, e.g. temperature, pressure, rotor speed F02C9/30 - F02C9/38, F02C9/44 take precedence
• CPC Class Codes: F05D 2270/303 Temperature
• CPC Class Codes: F05D 2270/709 with neural networks
• CPC Class Codes: H02P 2101/15 for wind-driven turbines
• CPC Class Codes: H02P 9/48 Arrangements for obtaining a constant output value at varying speed of the generator, e.g. on vehicle H02P9/04 - H02P9/46 take precedence

Abstract

A power generation system is disclosed. In one embodiment, the power generation system includes a fuel source to provide fuel, a turbogenerator, coupled to the fuel source, to generate AC power, and a power controller electrically coupled to the turbogenerator. The power controller includes a first power converter to convert the AC power to DC power on a DC bus, and a second power converter to convert the DC power on the DC bus to an output power to supply a load. The power controller to regulate the fuel to the turbogenerator, independent of a DC voltage on the DC bus. A capacitor, such as an electrochemical capacitor or a hybrid capacitor, is coupled to the DC bus to source instantaneous power to and sink instantaneous power from the DC bus, due to load changes, to stabilize the DC voltage on the DC bus.

Claims

1. A power generation system, comprising:

a fuel source to provide fuel;

a turbogenerator, coupled to the fuel source, to generate AC power;

a power controller, electrically coupled to the turbogenerator, including first and second power converters, said first power converter to convert said AC power to DC power on a DC bus, and said second power converter to convert said DC power on said DC bus to an output power to supply a load, said power controller to regulate the fuel to the turbogenerator, independent of a DC voltage on the DC bus; and

a capacitor coupled to the DC bus, said capacitor to source power to and sink power from the DC bus, due to load changes, to stabilize the DC voltage on the DC bus.

2. The power generation system of claim 1 further comprising a third power converter coupled between the DC bus and the capacitor, said power controller to controllably couple the capacitor to the DC bus via the third power converter.

3. The power generation system of claim 2 wherein the capacitor is an electrochemical capacitor.

4. The power generation system of claim 2 wherein the capacitor is a hybrid capacitor.

5. The power generation system of claim 1 wherein said second power converter comprises a DC/DC power converter to convert the DC voltage on the DC bus to a regulated DC output voltage to supply the load.

6. The power generation system of claim 1 wherein said second power converter comprises a DC/AC power converter to convert the DC power on the DC bus to an AC output power having a fixed frequency to supply the load.

7. The power generation system of claim 2 wherein when an increase in the load is detected, the power controller controllably couples the capacitor to the DC bus to source power to the DC bus to meet the increase in the load.

8. The power generation system of claim 7 wherein when the increase in the load is detected, the power controller increases the fuel to the turbogenerator to increase the DC power on the DC bus, and wherein when the DC power on the DC bus meets the increase in the load, said power controller recharges the capacitor to a predetermined level and then decouples the capacitor from the DC bus.

9. The power generation system of claim 8 wherein the predetermined level is less than 100 percent capacity of the capacitor.

10. The power generation system of claim 9 wherein when a decrease in the load is detected, the power controller decreases the fuel to the turbogenerator to decrease the DC power on the DC bus, and controllably couples the capacitor to the DC bus to absorb excess power on the DC bus.

11. The power generation system of claim 10 further comprising a brake resistor controllably coupled to the DC bus, said brake resistor to absorb the excess power on the DC bus under control of the power controller.

12. The power generation system of claim 2 wherein the turbogenerator includes a motor/generator and said first and second power converters are bi-directional, said power controller, in a startup mode, to (i) disable the second power converter to isolate the load from the DC bus, (ii) configure the third power converter to couple the capacitor to the DC bus and provide a startup DC voltage on the DC bus, and (iii) configure the first power converter to convert the startup DC voltage on the DC bus to power the motor/generator.

13. The power generation system of claim 2 further comprising a battery controllably coupled to the capacitor to charge the capacitor to allow said capacitor to power the turbogenerator during a startup mode.

14. The system of claim 1 wherein the turbogenerator comprises:

a shaft;

a generator, coupled to the shaft, to generate the AC power;

a compressor, coupled to the shaft, to provide a supply of compressed air;

a combustor coupled to receive the supply of compressed air and the fuel, said combustor to combust the fuel and to provide exhaust gas;

a turbine coupled the shaft and coupled to receive the exhaust gas, said exhaust gas to flow through the turbine to control a rotational speed of the shaft; and

a recuperator including a high pressure side coupled between the compressor and the combustor, and a low pressure side coupled to receive the exhaust gas from the turbine.

15. The power generation system of claim 14 further comprising a temperature sensor coupled to the power controller and the turbine to sense a temperature, said power controller to vary the supply of fuel to the combustor to control the temperature, said control of the temperature being independent of the DC voltage on the DC bus.

16. The system of claim 1 further comprising an additional turbogenerator coupled to the fuel source and to generate additional AC power, said power controller to independently regulate the fuel to said turbogenerator and said additional turbogenerator, independent of the DC voltage on the DC bus.

17. A power generation system, comprising:

a turbogenerator including a motor/generator and a turbine, said turbogenerator to generate AC power;

a power controller, electrically coupled to the turbogenerator, including first and second power converters, said first power converter to convert said AC power to DC power on a DC bus, and said second power converter to convert said DC power on said DC bus to an output power to supply a load, said power controller to regulate a speed of the turbine, independent of a DC voltage on the DC bus; and

a capacitor controllably coupled to the DC bus to source power to and sink power from the DC bus, due to load changes, to stabilize the DC voltage on the DC bus.

18. The power generation system of claim 17 further comprising a third power converter coupled between the DC bus and the capacitor, said power controller to controllably couple the capacitor to the DC bus via the third power converter.

19. The power generation system of claim 17 wherein the capacitor is at least one of an electrochemical capacitor and a hybrid capacitor.

20. The power generation system of claim 17 wherein said second power converter comprises a DC/DC power converter to convert the DC voltage on the DC bus to a regulated DC output voltage to supply the load.

21. The power generation system of claim 17 wherein said second power converter comprises a DC/AC power converter to convert the DC power on the DC bus to an AC output power having a fixed frequency to supply the load.

22. The power generation system of claim 17 wherein when an increase in the load is detected, the power controller controllably couples the capacitor to the DC bus to source power to the DC bus to meet the increase in the load.

23. The power generation system of claim 22 wherein when the increase in the load is detected, the power controller increases the fuel to the turbogenerator to increase the DC power on the DC bus, and wherein when the DC power on the DC bus meets the increase in the load, said power controller recharges the capacitor to a predetermined level and decouples the capacitor from the DC bus.

24. The power generation system of claim 23 wherein the predetermined level is less than 100 percent capacity of the capacitor.

25. The power generation system of claim 24 wherein when a decrease in the load is detected, the power controller decreases the fuel to the turbogenerator to decrease the DC power on the DC bus, and controllably couples the capacitor to the DC bus to sink excess power on the DC bus.

26. The power generation system of claim 18 wherein said first and second power converters are bi-directional, said power controller, in a startup mode, to (i) disable the second power converter to isolate the load from the DC bus, (ii) configure the third power converter to couple the capacitor to the DC bus and provide a startup DC voltage on the DC bus, and (iii) configure the first power converter to convert the startup DC voltage on the DC bus to power the motor/generator.

27. The power generation system of claim 18 further comprising a battery controllably coupled to the capacitor to charge the capacitor to allow said capacitor to power the motor/generator during a startup mode.

28. The power generation system of claim 17 wherein the turbogenerator further comprises:

a shaft;

a generator, coupled to the shaft, to generate the AC power;

a compressor, coupled to the shaft, to provide a supply of compressed air;

a combustor coupled to receive the supply of compressed air and the fuel, said combustor to combust the fuel and to provide exhaust gas;

the turbine coupled the shaft and coupled to receive the exhaust gas, said exhaust gas to flow through the turbine to control a rotational speed of the shaft; and

a recuperator including a high pressure side coupled between the compressor and the combustor, and a low pressure side coupled to receive the exhaust gas from the turbine.

29. A power generation system, comprising:

a turbogenerator including a motor/generator and a turbine, said turbogenerator to generate AC power; and

a power control means, electrically coupled to the turbogenerator, including first, second, and third power converter means and electrochemical capacitor means, said first power converter means to convert said AC power to DC power on a DC bus, and said second power converter means to convert said DC power on said DC bus to an output power to supply a load, said power control means controllably couples said electrochemical capacitor means to the DC bus to source power to and sink power from the DC bus, due to load changes, to stabilize the DC voltage on the DC bus, said power control means to regulate a speed of the turbine, independent of a DC voltage on the DC bus.