ENERGY STORAGE SYSTEMS

• US 20120248873A1
• Filed: 03/06/2012
• Published: 10/04/2012
• Est. Priority Date: 09/07/2009
• Status: Active Grant

• Current Assignee: Hitachi Energy Limited (Hitachi, Ltd.)
• Original Assignee: ABB Research Ltd. (ABB Limited)
• Inventors: OUDALOV, Alexandre, Mercangoez, Mehmet, Von Hoff, Thomas
• Granted Patent: US 9,705,332 B2
• Time in Patent Office: Days
• US Class Current: 307/52
• CPC Class Codes: H02J 3/32 using batteries with converting means

Abstract

A method for controlling an energy storage system for connection to a power system, and such an energy storage system are provided. The method makes use of a model based predictive controller to optimize the charging/discharging rates of energy storage elements in a hybrid energy storage system. The method includes determining respective desired charging/discharging rates for the energy storage elements in dependence upon state of charge predictions from respective models of the storage elements, using model predictive control, and adjusting respective charging/discharging rates of the storage elements in accordance with the determined rates. The energy system includes a controller configured to control respective charging/discharging rates of the energy storage elements in accordance with the method.

Claims

1. A method for controlling an energy storage system for connection to a power system, wherein the energy storage system includes a first energy storage element and a second energy storage element having a first operational characteristic and a second operational characteristic, respectively, wherein the first operational characteristic is a slow energy storage and the second operational characteristic is a fast energy storage, the method comprising:

determining respective desired charging/discharging rates for the first and second energy storage elements in dependence upon state of charge predictions from respective models of the first and second storage elements, using model predictive control; and

adjusting respective charging/discharging rates of the first and second storage elements in accordance with the determined rates.

2. A method as claimed in claim 1, wherein the respective models of the first and second storage elements are operable to determine a state of charge of the corresponding storage element.

3. A method as claimed in claim 1, wherein the respective desired charging/discharging rates are determined in dependence upon the respective models of the first and second storage elements, and upon a time dependent forecast of properties of the first and second storage elements and of the power system.

4. A method as claimed in claim 1, comprising:

determining a predicted state of charge of each of the storage elements from respective models thereof;

receiving a time dependent forecast relating to properties of the storage elements and of the power system;

determining respective desired charging/discharging rates for the first and second storage elements in dependence upon the respective predicted states of charge for the first and second storage elements, and upon the time dependent forecast;

adjusting the respective charging/discharging rates for the first and second storage elements in accordance with the determined charging/discharging rates.

5. A method as claimed in claim 1, wherein the determining of the respective charging/discharging rates comprises determining a charging/discharging rate sequence.

6. A method as claimed in claim 1, wherein the charging/discharging rate for the first storage element is determined less frequently than the charging/discharging rate for the second storage element.

15. A method as claimed in claim 2, wherein the respective desired charging/discharging rates are determined in dependence upon the respective models of the first and second storage elements, and upon a time dependent forecast of properties of the first and second storage elements and of the power system.

16. A method as claimed in claim 15, wherein the determining of the respective charging/discharging rates comprises determining a charging/discharging rate sequence.

17. A method as claimed in claim 3, wherein the determining of the respective charging/discharging rates comprises determining a charging/discharging rate sequence.

18. A method as claimed in claim 4, wherein the determining of the respective charging/discharging rates comprises determining a charging/discharging rate sequence.

19. A method as claimed in claim 18, wherein the charging/discharging rate for the first storage element is determined less frequently than the charging/discharging rate for the second storage element.

7. An energy storage system for connection to a power system, the energy storage system comprising:

a first energy storage element having a first operational characteristic, the first energy storage element including a slow energy storage system element;

a second energy storage elements having a second operational characteristic, the second storage element including a fast energy storage system element, and

a controller configured to control respective charging/discharging rates of the first and second energy storage elements by;

determining respective desired charging/discharging rates for the first and second energy storage elements in dependence upon state of charge predictions from respective models of the first and second storage elements, using model predictive control; and

adjusting respective charging/discharging rates of the first and second storage elements in accordance with the determined rates.

8. An energy storage system as claimed in claim 7, wherein the controller comprises a combination of central and distributed controllers.

9. An energy storage system as claimed in claim 8, wherein the slow energy storage system element has a slow reaction time of at least ten seconds, and the fast energy storage element has a short reaction time and is configured to reach a high output in less than one second.

10. An energy storage system as claimed in claim 7, wherein the controller includes a model storage unit configured to store data relating to respective models of the first and second storage elements.

11. An energy storage system as claimed in claim 7, wherein each of the first and second energy storage element respectively includes:

at least one sensor configured to detect at least one operating parameter of the energy storage element concerned; and

a communication device configured to receive operating parameter information from the at least one sensor, transmit the received operating parameter information to the controller, and receive control information from the controller.

12. An energy storage system as claimed in claim 7, comprising at least one of a plurality of the first energy storage elements and a plurality of the second energy storage elements.

13. An energy storage system as claimed in claim 12, wherein at least one of the plurality of first energy storage elements and the plurality of second energy storage elements is distributed by location.

14. An energy storage system as claimed in claim 7, comprising:

a sensing unit configured to detect an operating parameter of the power system to which the energy storage system is connected.

20. An energy storage system as claimed in claim 9, wherein the controller includes a model storage unit configured to store data relating to respective models of the first and second storage elements.

21. An energy storage system as claimed in claim 20, wherein each of the first and second energy storage element respectively includes:

at least one sensor configured to detect at least one operating parameter of the energy storage element concerned; and

a communication device configured to receive operating parameter information from the at least one sensor, transmit the received operating parameter information to the controller, and receive control information from the controller.

22. An energy storage system as claimed in claim 21, comprising at least one of a plurality of the first energy storage elements and a plurality of the second energy storage elements.

23. An energy storage system as claimed in claim 22, wherein at least one of the plurality of first energy storage elements and the plurality of second energy storage elements is distributed by location.

24. An energy storage system as claimed in claim 20, comprising:

a sensing unit configured to detect an operating parameter of the power system to which the energy storage system is connected.

25. A power distribution system comprising:

the energy storage system as claimed in claim 7; and

a power system connected to the energy storage system.