SMART MICROGRID RECONFIGURABLE AC INTERFACE

• US 20120175955A1
• Filed: 01/12/2011
• Published: 07/12/2012
• Est. Priority Date: 01/12/2011
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Carralero, Michael A., Quiambao, Jimmy M., Nguyen, Sang H.
• Granted Patent: US 8,766,474 B2
• Time in Patent Office: Days
• US Class Current: 307/38
• CPC Class Codes: H02J 2310/10 The network having a local or delimited stationary reach
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 9/062 for AC powered loads

Abstract

Presented is a system and method for providing reconfigurable AC interfaces for AC power systems. The method comprises embedding a reconfigurable AC interface for transferring power between power sources and loads, monitoring the voltage and current of the interfaces of the reconfigurable AC interface, and switching between power sources based on the monitoring. The system comprises a reconfigurable AC interface further comprising an inverter for converting DC power to AC, transfer switches with interfaces for connecting to the inverter, other transfer switches, and AC busses, and a controller that dynamically configures the transfer switches to transfer power between the inverter, and AC busses.

Claims

1. A method for controlling a microgrid, comprising:

embedding a reconfigurable AC interface with interface nodes in the microgrid, the microgrid comprising a load and a plurality of power sources in electrical communication with said interface nodes;

configuring said reconfigurable AC interface to transfer power from at least one of said power sources through said reconfigurable AC interface to said load;

monitoring a voltage and current of at least one of said interface nodes of said reconfigurable AC interface; and

switching said reconfigurable AC interface to transfer power from a different power source to said load based on said monitoring of said voltage and said current.

2. The method of claim 1, further comprising:

monitoring a frequency and a phase of said interface node; and

synchronizing an internal phase locked oscillator of said reconfigurable AC interface to said frequency and said phase.

3. The method of claim 1, further comprising:

providing an uninterruptible supply of power to said load by dynamically reconfiguring said reconfigurable AC interface to supply power to said load from a first of said power sources to at least a second of said power sources.

4. The method of claim 3, wherein said first of said power sources comprises a utility power grid, and said second of said power sources comprises a distributed energy resource system.

5. The method of claim 4, wherein said reconfigurable AC interface inverts a DC power from said distributed energy resource system into an AC power for said load.

6. The method of claim 1, wherein said power sources comprise a utility power grid, and a distributed energy resource system, and further comprising:

transferring power from said distributed energy resource system to said utility power grid through said reconfigurable AC interface.

7. The method of claim 6, further comprising:

transferring power from said distributed energy resource system to said load through said reconfigurable AC interface.

8. The method of claim 6, further comprising:

isolating a power source electrically connected to an interface of reconfigurable AC interface if said power of said power source falls below a specified power; and

reconnecting said power source if said power returns to a specified power for a specified period of time.

9. The method of claim 8, further comprising:

transferring power from a utility power grid to said load through said reconfigurable AC interface.

10. The method of claim 1, further comprising:

load balancing power from a first of said power sources that is transferred across a transmission line to one of a load and a second of said power sources.

11. A reconfigurable AC interface for microgrids, comprising:

an inverter for converting a DC power source to an AC power source;

a first transfer switch comprising an electrical interface to said inverter and an electrical interface to a first AC bus; and

,

a second transfer switch comprising an electrical interface to said first transfer switch, and an electrical interface to a second AC bus; and

a controller adapted to dynamically configure said first transfer switch and said second transfer switch to transfer power between said inverter, said first AC bus, and said second AC bus.

12. The reconfigurable AC interface of claim 11, wherein said second AC bus is electrically connected to a load, and wherein said first AC bus is electrically connected to a utility power grid, and wherein said controller is adapted to dynamically configure said first transfer switch and said second transfer switch so that said load is isolated from said utility power grid, and said load receives power from said inverter, without interrupting power to said load.

13. The reconfigurable AC interface of claim 12, wherein said controller is adapted to receive a signal to isolate said load from said utility power grid.

14. The reconfigurable AC interface of claim 11, further comprising:

a sensor for detecting electrical parameters of said first AC bus; and

wherein said controller is adapted to dynamically configure said first transfer switch to isolate said first AC bus based on said electrical parameters detected on said first AC bus.

15. The reconfigurable AC interface of claim 14, wherein said controller is adapted to dynamically configures said first transfer switch to reconnect to said first AC bus based on said electrical parameters on first AC bus attaining a specified voltage and current for a predetermined period of time.

16. The reconfigurable AC interface of claim 11, further comprising:

a second inverter for converting said DC power source to an AC power source; and

wherein said second transfer switch further comprises an electrical interface to said second inverter; and

wherein said controller adapted to dynamically configure said first transfer switch to transfer power from said inverter to said first AC bus, and dynamically configure said second transfer switch to transfer power between said second inverter and said second AC bus.

17. The reconfigurable AC interface of claim 11, further comprising:

a sensor for monitoring a frequency and a phase of said electrical interface to said first AC bus; and

a phase locked oscillator in communication with said sensor for synchronizing said reconfigurable AC interface to said frequency and said phase.

18. The reconfigurable AC interface of claim 11, wherein said DC power source is a distributed energy resource system, said first AC bus is in electrical communication with a utility power grid, and said second AC bus is in electrical communication with a load.

19. A system, comprising:

a plurality of inverters for converting a DC power source to an AC power source;

a plurality of interconnected transfer switches for electrically interconnecting between said inverters, an AC power source, and an AC power bus;

a plurality of sensors for monitoring said DC power source and said AC power source; and

a controller that dynamically configures said interconnected transfer switches to control the flow of power between said inverters, said AC power source, and said AC power bus, based at least in part upon a sensor reading from said plurality of sensors.

20. The system of claim 19, wherein said controller configures said interconnected transfer switches to the configuration selected from the group consisting of electrically isolating said AC power source from a load on said AC power bus;

switching said AC power bus from said AC power source to one of said inverters without interrupting power to said AC power bus;

electrically isolating said plurality of inverters from said AC power source; and

electrically connecting a first of said inverters to said AC power source and a second of said inverters to said AC power bus.