Energy storage system

• US 8,552,591 B2
• Filed: 12/06/2010
• Issued: 10/08/2013
• Est. Priority Date: 12/04/2009
• Status: Active Grant

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Choi, Looney
• Primary Examiner(s): Deberadinis, Robert L.
• Application Number:
  US12/961,473
• Publication Number:
  US 20110133556A1
• Time in Patent Office: 1,037 Days
• Field of Search: 307/66
• US Class Current: 307/66
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 7/0018 using separate charge circuits
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

An energy storage system capable of improving the lifespan of a battery pack while supplying power in a secured manner is provided. In one embodiment, the energy storage system includes a plurality of battery packs connected between a grid and a solar cell to charge/discharge power. The energy storage system includes an inverter connected among the grid, the solar cell, and the battery pack and inverting an alternating current (AC) power to a direct current (DC) power and vice versa according to charging/discharging operations. The energy storage system includes a converter connected to the solar cell, the battery pack, and the grid and converting power supplied from the solar cell, and a plurality of bidirectional converters connected to the plurality of battery packs, the solar cell, and the grid and connected in one-to-one correspondence to the plurality of battery packs and converting the power for charging/discharging the battery pack. The energy storage system further includes a controller connected to the inverter, the converter, and the plurality of bidirectional converters and applying drive signals to sequentially drive the plurality of bidirectional converters.

Claims

1. An energy storage system comprising:

an inverter electrically connected to a grid, the inverter inverting an alternating current (AC) voltage to a direct current (DC) voltage or inverting a DC voltage to an AC voltage;

a converter connected to a solar cell, the converter converting a DC voltage to another DC voltage;

a plurality of unit bidirectional converters coupled to the inverter and the converter;

a plurality of unit battery packs, each of the unit battery packs electrically connected to a different corresponding one of the unit bidirectional converters; and

a controller connected to the inverter, the converter, and the plurality of unit bidirectional converters, the controller applying drive signals to the unit bidirectional converters to sequentially drive the unit bidirectional converters.

2. The energy storage system of claim 1, wherein the controller sequentially turns on the plurality of the unit battery packs by sequentially driving the plurality of the unit bidirectional converters.

3. The energy storage system of claim 1, wherein the controller drives one of the unit bidirectional converters during a driving period.

4. The energy storage system of claim 1, wherein the controller divides the plurality of the unit bidirectional converters into a plurality of groups, and sequentially drives the unit bidirectional converters group by group.

5. The energy storage system of claim 4, wherein at least one of the unit bidirectional converters in one of the groups is included in another of the groups.

6. The energy storage system of claim 1, wherein the unit battery packs are connected in parallel with one another.

7. The energy storage system of claim 1, wherein each of the plurality of the unit battery packs and a corresponding one of the plurality of the unit bidirectional converters are implemented in a single package.

8. The energy storage system of claim 1, further comprising a capacitive device connected between the converter and the inverter and storing power supplied from the converter.

9. The energy storage system of claim 1, wherein power supplied from the inverter is supplied to a load connected between the grid and the inverter.

10. The energy storage system of claim 1, wherein the converter includes a maximum power point tracking (MPPT) converter that adjusts a voltage to obtain a maximum power available from the solar cell.

11. An energy storage system comprising:

a converter connected to a renewable energy source, the converter converting a direct current (DC) voltage supplied from the renewable energy source to another DC voltage;

a plurality of unit battery packs;

a plurality of unit bidirectional converters electrically coupled to the converter and the plurality of the unit battery packs, each of the unit battery packs connected to one of the unit bidirectional converters;

an inverter electrically connected to a grid, the inverter inverting an alternating current (AC) voltage supplied from the grid to a DC voltage, the inverter electrically coupled to the converter and the plurality of the unit bidirectional converters, the inverter inverting a DC voltage supplied from the converter or from the plurality of the unit bidirectional converters to an AC voltage; and

a controller electrically connected to the inverter, to the converter, and to the plurality of unit bidirectional converters, the controller applying a drive signal during a drive period to at least one of the unit bidirectional converters, a voltage from one of the plurality of the unit battery packs, the converter and the inverter being applied to the at least one of the unit bidirectional converters whenever the drive signal is applied to the at least one of the unit bidirectional converters.

12. The energy storage system of claim 11, wherein the controller applies the drive signal to only one of the unit bidirectional converters during the drive period.

13. The energy storage system of claim 11, wherein the controller applies the drive signal to at least two of the unit bidirectional converters during the drive period.

14. The energy storage system of claim 11, wherein the unit battery packs are electrically connected in parallel with one another.

15. The energy storage system of claim 11, wherein an AC voltage inverted from the inverter is supplied to a load connected to the grid and the inverter, or is supplied to the grid.

16. The energy storage system of claim 11, wherein the converter includes a maximum power point tracking (MPPT) converter that adjusts a voltage to obtain a maximum power available from the solar cell.