POWER STORAGE SYSTEM AND METHOD OF CONTROLLING THE SAME

• US 20110148205A1
• Filed: 12/14/2010
• Published: 06/23/2011
• Est. Priority Date: 12/17/2009
• Status: Active Grant

• Current Assignee: Hanwha Solutions Corporation (Hanwha Corporation)
• Original Assignee: Samsung SDI Company Limited
• Inventors: Moon, Chong-Sop
• Granted Patent: US 8,810,066 B2
• Time in Patent Office: Days
• US Class Current: 307/65
• CPC Class Codes: H02J 2300/20 The dispersed energy generation being of renewable origin
• CPC Class Codes: H02J 2300/26 involving maximum power point tracking control for photovoltaic sources maximum power point systems in particular G05F1/67
• CPC Class Codes: H02J 2300/28 The renewable source being wind energy wind motors F03D
• CPC Class Codes: H02J 2300/40 wherein a plurality of decentralised, dispersed or local energy generation technologies are operated simultaneously
• CPC Class Codes: H02J 3/32 using batteries with converting means
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: Y02B 10/70 Hybrid systems, e.g. uninterruptible or back-up power supplies integrating renewable energies
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y02E 10/76 Power conversion electric or electronic aspects
• CPC Class Codes: Y02E 70/30 Systems combining energy storage with energy generation of non-fossil origin
• CPC Class Codes: Y02P 80/20 using renewable energy

Abstract

A power storage system and method of controlling the system is disclosed. The power storage system is connected to a power generation system and a grid. If a remaining amount of power of a battery is insufficient when the grid is in a quasi-normal state, the battery is charged by directly receiving electric power from the grid, and thus electric power is available for the if the grid subsequently goes back into the abnormal state.

Claims

1. A power storage system, configured to receive power from a power generation system and a grid and to provide power to a load, the power storage system comprising:

a first power converter connected between the power generation system and a first node, and configured to convert the electric power generated by the power generation system to a direct current (DC) voltage of the first node;

a bidirectional inverter connected between the first node and a second node, wherein the bidirectional converter is configured to output power of the DC voltage of the first node to the second node after performing DC to alternating current (AC) conversion on the DC voltage of the first node, and to output power of an AC voltage of the second node to the first node after performing AC-DC conversion;

a bidirectional converter connected between a battery and the first node, wherein the bidirectional inverter is configured to output power of the DC voltage of the first node to the battery after performing DC-DC conversion, and to output power of a DC voltage from the battery to the first node after performing DC-DC conversion, wherein the battery comprises at least one battery cell;

a battery management system configured to control charging and discharging of the at least one battery cell; and

an integrated controller configured to charge the battery with electric power from the power generation system and the grid, and to control the first power converter, the bidirectional converter, the bidirectional inverter, and the battery management system so that the electric power is selectively supplied to the load and the grid by discharging the battery,

wherein the integrated controller is configured to charge the battery with electric power from the grid if the remaining amount of power of the battery is insufficient and the grid is in a quasi-normal state.

2. The power storage system of claim 1, further comprising:

a first switch connected between the bidirectional inverter and the second node; and

a second switch connected between the second node and the grid,

wherein the integrated controller is configured to turn on the first and second switches if the grid is in a normal state, to turn on the first switch and to turn off the second switch if the grid is in an abnormal state, and to turn off the first switch and to turn on the second switch if the grid is in a quasi-normal state.

3. The power storage system of claim 1, wherein the quasi-normal state occurs before the grid is in a normal state after the grid has been in an abnormal state.

4. The power storage system of claim 1, further comprising a second power converter connected between the battery and the grid, wherein the second power converter is configured to output power of the AC voltage from the grid to the battery after performing AC-DC conversion if the grid is in the quasi-normal state.

5. The power storage system of claim 4, wherein the integrated controller is configured to check the remaining amount of power of the battery by controlling the battery management system if the grid is in the quasi-normal state, and if the remaining amount of power is insufficient, to control the battery management system and the second power converter to charge the battery with electric power from the grid.

6. The power storage system of claim 1, wherein the integrated controller is configured to check the remaining amount of power of the battery by controlling the battery management system if the grid is in the quasi-normal state, and if the remaining amount of power is insufficient, to control the first power converter, the bidirectional converter, and the battery management system to charge the battery with electric power from the power generation system.

7. The power storage system of claim 1, wherein the power generation system includes the power generation system and is configured to generate electric power by using solar energy, such as solar heat or sunlight, wind power, geothermal heat, water power, marine power, or hydrogen.

8. The power storage system of claim 7, wherein the power generation system is a solar power generation system and the first power converter adjusts a power generation voltage level according to the maximum power supply voltage for receiving the maximum power from the solar power generation system.

9. The power storage system of claim 1, further comprising a DC voltage stabilizer connected between the first node and the bidirectional inverter, wherein the DC voltage stabilizer is configured to stabilize a voltage of the first node.

10. The power storage system of claim 1, wherein, if the grid is in a normal state, the integrated controller is configured to control the first power converter, the bidirectional inverter, the bidirectional converter, and the battery management system to supply electric power generated by the power generation system to at least one of the load and the grid, to charge the battery, to store electric power from the grid in the battery, and to supply the electric power stored in the battery to at least one of the load and to the grid.

11. The power storage system of claim 1, wherein, if the grid is in an abnormal state, the integrated controller is configured to control the first power converter, the bidirectional inverter, the bidirectional converter, and the battery management system to supply electric power generated by the power generation system to the load, to supply the electric power stored in the battery to the load, and to store the electric power generated by the power generation system in the battery.

12. A method of controlling a power storage system configured to receive power from a power generation system and a grid, and to provide power to a load, a power storage device, and the grid, wherein the power storage system comprises a battery cell, a battery management system for controlling charging and discharging of the battery cell, first and second switches for connecting the load and the grid, and an integrated controller for controlling the battery management system and the first and second switches, the method comprising:

monitoring the state of the grid;

if the state of the grid is abnormal, controlling the first and second switches so as to disconnect the load and the power storage system from the grid; and

if the grid transitions to a quasi-normal state, charging the battery with electric power from the grid.

13. The method of claim 12, further comprising, if the grid is in the abnormal state, supplying electric power from the battery to the load.

14. The method of claim 12, further comprising, if the grid is in the abnormal state, supplying electric power generated by the power generation system to the load.

15. The method of claim 12, further comprising, if the grid is in the quasi-normal state:

controlling the first and second switches to connect the load to the grid; and

supplying electric power from the grid to the load.

16. The method of claim 12, further comprising, if the grid is in the quasi-normal state:

conditionally charging the battery with electric power form the grid according to a remaining amount of power in the battery.

17. The method of claim 12, further comprising, if the grid is in the quasi-normal state:

conditionally charging the battery with electric power from the power generation system according to a remaining amount of power in the battery.

18. A power storage system, configured to receive power from a power generation system and a grid and to provide power to a load, the power storage system comprising:

a first switch configured to selectively connect the battery and the power generation system to the load;

a second switch configured to connect the grid to the load; and

a controller configured to determine a state of the grid and a state of the battery and to control the first and second switches according to the state of the grid.

19. The system of claim 18, wherein the controller is configured to turn the first switch on and to turn the second switch off if the grid is in an abnormal state.

20. The system of claim 18, wherein the controller is configured to turn the first switch off and to turn the second switch on if the grid is in quasi-normal state.

21. A method of operating a power storage system comprising a battery, the system connected to a power generator, a load, and a power grid, the method comprising:

determining the state of the power grid;

if the power grid is in a normal state, selectively charging the battery with power from at least one of the power generator and the power grid, and selectively providing power to the load from at least one of the power generator, the battery, and the power grid;

if the power grid is in an abnormal state, selectively charging the battery with power from the power generator, and selectively providing power to the load from at least one of the power generator and the battery; and

if the power grid is in a quasi-normal state, selectively charging the battery with power from at least one of the power generator and the power grid, and selectively providing power to the load from the grid, wherein an electrical path used to charge the battery if power grid is in the quasi-normal state is different than an electrical path used to the battery if power grid is in the normal or abnormal.