Microgrid electric power generation systems and associated methods

• US 10,559,957 B2
• Filed: 12/07/2016
• Issued: 02/11/2020
• Est. Priority Date: 12/07/2015
• Status: Active Grant

• Current Assignee: Wattsup Power A/S
• Original Assignee: Maersk Drilling A/S
• Inventors: Pedersen, John Ron, Speiermann, Martin
• Primary Examiner(s): Ro, Bentsu
• Application Number:
  US16/060,144
• Publication Number:
  US 20180366950A1
• Time in Patent Office: 1,161 Days
• Field of Search: 318149
• CPC Class Codes: F02D 19/06 peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
• CPC Class Codes: H02J 2300/10 The dispersed energy generation being of fossil origin, e.g. diesel generators
• CPC Class Codes: H02J 2310/10 The network having a local or delimited stationary reach
• CPC Class Codes: H02J 2310/42 for ships or vessels
• CPC Class Codes: H02J 3/30 using dynamo-electric machines coupled to flywheels
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/46 Controlling of the sharing of output between the generators, converters, or transformers
• CPC Class Codes: Y02E 60/16 Mechanical energy storage, e.g. flywheels or pressurised fluids

Abstract

A method for operating a microgrid electric power generation system includes delivering energy to an electric power bus at least partially from one or more kinetic generators electrically coupled to the electric power bus, controlling the one or more kinetic generators in response to a change in a load such that a magnitude of a voltage on the electric power bus remains within a predetermined voltage range, and controlling one or more combustion generators electrically coupled to the electric power bus based at least in part on an operating state of the one or more kinetic generators. The one or more kinetic generators are capable of (a) delivering energy stored therein to the electric power bus, and (b) storing energy in kinetic form.

Claims

1. A method for operating a microgrid electric power generation system, comprising:

delivering energy to a first electric power bus at least partially from one or more kinetic generators electrically coupled to the first electric power bus, the one or more kinetic generators storing energy therein in kinetic form;

controlling the one or more kinetic generators in response to a change in a load powered by the first electric power bus such that a magnitude of a voltage on the first electric power bus remains within a predetermined voltage range, while maintaining an output power of one or more combustion generators electrically coupled to the first electric power bus at a constant value during the change in load; and

controlling the one or more combustion generators based at least in part on an operating state of the one or more kinetic generators.

2. The method of claim 1, further comprising controlling the one or more combustion generators independent of the voltage on the first electric power bus.

3. The method of claim 1, wherein a magnitude of the change in load is at least ten percent of a magnitude of the load before the change in load.

4. The method of claim 3, wherein a duration of the change in load is at least one second.

5. The method of claim 1, wherein the one of more kinetic generators are electrically coupled to the first electric power bus via at least one of a power converter and a transformer.

6. The method of claim 5, wherein the one of more kinetic generators are electrically coupled to the first electric power bus via a second electric power bus.

7. The method of claim 1, further comprising maintaining the output power of the one or more combustion generators at eighty percent or more of a maximum rated output power of the one or more combustion generators during the change in load.

8. The method of claim 1, further comprising controlling the one or more combustion generators in response to a signal indicating an upcoming change in the load.

9. The method of claim 1, wherein controlling the one or more combustion generators based at least in part on the operating state of the one or more kinetic generators comprises controlling the one or more combustion generators according to one or more of (a) kinetic energy storage level of the one or more kinetic generators and (b) kinetic energy loss rate of the one or more kinetic generators.

10. The method of claim 1, further comprising:

controlling the one or more kinetic generators in response to the change in the load within 10 ms of the change in load; and

controlling the one or more combustion generators at least one second after the change in load.

11. The method of claim 10, the step of controlling the one or more combustion generators comprising:

initiating change in operation of the one or more combustion generators; and

changing power output of the one or more combustion generators at least one second after the step of initiating.

12. The method of claim 1, further comprising providing an output power of at least 1 MW from the one or more kinetic generators to the load for at least 5 minutes.

13. The method of claim 1, further comprising spinning a rotor of each kinetic generator at a speed of at least 30,000 revolutions per minute.

14. The method of claim 1, wherein the first electric power bus is an AC electric power bus and the method further comprises controlling the one or more kinetic generators such that frequency of the voltage on the first electric power bus remains within a predetermined frequency range.

15. A microgrid electric power generation system, comprising:

a first electric power bus;

one or more combustion power sources, each combustion power source including;

a combustion generator electrically coupled to the first electric power bus, and

a first control subsystem configured to control delivery of power by the combustion generator to the first electric power bus,

each combustion power source having a respective first time constant representing an amount of time required for the combustion power source to change its power output by ten percent; and

one or more kinetic energy subsystems, each kinetic energy subsystems including;

a kinetic generator capable of (a) delivering energy stored therein to the first electric power bus, and (b) storing energy from the first electric power bus in kinetic form,

a power converter electrically coupling the kinetic generator to the first electric power bus, and

a second control subsystem configured to control the kinetic generator and the power converter of the kinetic energy subsystem such that magnitude of a voltage on the first electric power bus remains within a predetermined voltage range,

each kinetic energy subsystem having a respective second time constant representing an amount time required for the kinetic energy subsystem to change its power storage or delivery by ten percent, each second time constant being smaller than each first time constant.

16. The microgrid electric power generation system of claim 15, wherein the first control subsystem of each combustion power source is further configured to control its respective combustion generator independent of the voltage on the first electric power bus.

17. The microgrid electric power generation system of claim 15, further comprising a transformer and a second electric power bus, each kinetic generator being electrically coupled to the first electric power bus at least via its respective power converter, the second electric power bus, and the transformer.

18. The microgrid electric power generation system of claim 15, wherein each second time constant is no more than ten percent of each first time constant.

19. The microgrid electric power generation system of claim 15, wherein each first control subsystem is further configured to control its respective combustion generator based at least in part on an operating state of the kinetic generators of the one or more kinetic energy subsystems.

20. The microgrid electric power generation system of claim 19, the operating state of the kinetic generators of the one or more kinetic energy subsystems comprising at least one of (a) kinetic energy storage level of the kinetic generators and (b) kinetic energy loss rate of the kinetic generators.

21. The microgrid electric power generation system of claim 15, each second control subsystem further configured to control its respective kinetic generator according to a load powered by the first electric power bus.

22. The microgrid electric power generation system of claim 21, each second control subsystem being further configured to control its respective kinetic generator according to a signal indicating an upcoming change in the load powered by the first electric power bus.

23. The microgrid electric power generation system of claim 15, wherein the first electric power bus is an AC electric power bus and each second control subsystem is further configured to control its respective kinetic generator such that frequency of the voltage on the first electric power bus remains within a predetermined frequency range.

24. The microgrid electric power generation system of claim 15, each kinetic generator having an energy storage capacity of at least 100 kWh and a response time of no more than 2 milliseconds.

25. The microgrid electric power generation system of claim 24, the kinetic generators of the one or more kinetic energy subsystems collectively having a maximum power output of at least 4 MW.

26. The microgrid electric power generation system of claim 15, the kinetic generators of the one or more kinetic energy subsystems collectively having a maximum power output that is at least as large as a maximum power output of any one combustion generator of the one or more combustion power sources.

27. The microgrid electric power generation system of claim 15, the first electric power bus being one or more of a direct current (DC) electric power bus and an alternating current (AC) electric power bus.

28. The microgrid electric power generation system of claim 15, each kinetic generator having horizontal extent of less than 2 meters.

29. The microgrid electric power generation system of claim 15, a rotor of each kinetic generator being capable of rotating at a speed of at least 30,000 revolutions per minute.