Method and apparatus for storing and depleting energy

• US 10,778,025 B2
• Filed: 12/19/2016
• Issued: 09/15/2020
• Est. Priority Date: 03/14/2013
• Status: Active Grant

• Current Assignee: Solaredge Technologies Incorporated
• Original Assignee: Solaredge Technologies Incorporated
• Inventors: Gazit, Meir
• Primary Examiner(s): Tran, Thienvu V
• Assistant Examiner(s): Baxter, Brian K
• Application Number:
  US15/383,518
• Publication Number:
  US 20170201113A1
• Time in Patent Office: 1,366 Days
• Field of Search: 307 82
• CPC Class Codes: H02J 3/32 using batteries with converting means
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0018 using separate charge circuits
• CPC Class Codes: H02J 7/0025 Sequential battery discharge in systems with a plurality of batteries
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: H02M 3/1582 Buck-boost converters H02M3/1584 takes precedence
• CPC Class Codes: H02M 7/217 using semiconductor devices only

Abstract

A method to control storage into and depletion from multiple energy storage devices. The method enables an operative connection between the energy storage devices and respective power converters. The energy storage devices are connectable across respective first terminals of the power converters. At the second terminals of the power converter, a common reference is set which may be a current reference or a voltage reference. An energy storage fraction is determined respectively for the energy storage devices. A voltage conversion ratio is maintained individually based on the energy storage fraction. The energy storage devices are stored individually with multiple variable rates of energy storage through the first terminals. The energy storage is complete for the energy storage devices substantially at a common end time responsive to the common reference.

Claims

1. A method comprising:

determining a corresponding charge fraction for each of a plurality of energy storage devices, wherein the plurality of energy storage devices are connected one-to-one to a plurality of power converters; and

for each of the plurality of energy storage devices, independently maintaining, by a corresponding power converter of the plurality of power converters, a corresponding voltage conversion ratio such that the plurality of energy storage devices are charged within a common charge time that is based on;

the corresponding charge fractions for all of the plurality of energy storage devices, and

transfer of power from an electrical network and to the plurality of energy storage devices.

2. The method of claim 1, wherein, for each of the plurality of energy storage devices, the independently maintaining the corresponding voltage conversion ratio comprises:

updating, based on corresponding charge capacities for all of the plurality of energy storage devices, one of a common current reference or a common voltage reference at terminals of the plurality of power converters, wherein the terminals are connected to an alternating-current-to-direct-current inverter.

3. The method of claim 2, wherein the common charge time is based on the updated one of the common current reference or the common voltage reference.

4. The method of claim 2, wherein the updating comprises:

determining, by the plurality of power converters and via a central controller, a second common current reference or a second common voltage reference; and

setting direct-current terminals of the alternating-current-to-direct-current inverter to the second common voltage reference or the second common current reference.

5. The method of claim 2, wherein the updating comprises updating the common current reference at serially connected terminals of the plurality of power converters that form a serial connection, wherein the serial connection is connected to the alternating-current-to-direct-current inverter.

6. The method of claim 2, wherein the updating comprises updating the common voltage reference at the terminals of the plurality of power converters that are connected in parallel to form a parallel connection, wherein the parallel connection is connected to the alternating-current-to-direct-current inverter.

7. The method of claim 1, further comprising an action of:

monitoring a plurality of fuel gauges respectively connected one-to-one to the plurality of energy storage devices,

wherein the determining of the respective charge fraction for each of the plurality of energy storage devices is based on the monitoring of the plurality of fuel gauges.

8. A method comprising:

determining a corresponding charge fraction for each of a plurality of energy storage devices, wherein the plurality of energy storage devices are connected one-to-one to a plurality of power converters; and

for each of the plurality of energy storage devices, independently maintaining, by a corresponding power converter of the plurality of power converters, a corresponding voltage conversion ratio such that the plurality of energy storage devices are discharged within a common discharge time that is based on;

the corresponding charge fractions for all of the plurality of energy storage devices, and

transfer of power from the plurality of energy storage devices and to an electrical network.

9. The method of claim 8, wherein, for each of the plurality of energy storage devices, the independently maintaining of the corresponding voltage conversion ratio comprises:

updating, based on corresponding charge capacities for all of the plurality of energy storage devices, one of a common current reference or a common voltage reference at terminals of the plurality of power converters, wherein the terminals are connected to a direct-current-to-alternating-current inverter.

10. The method of claim 9, wherein the common discharge time is based on the updated one of the common current reference or the common voltage reference.

11. The method of claim 9, wherein the updating comprises:

determining, by the plurality of power converters and via a central controller, a second common current reference or a second common voltage reference; and

setting direct-current terminals of the direct-current-to-alternating-current inverter to the second common voltage reference or the second common current reference.

12. The method of claim 9, wherein the updating comprises updating the common current reference at serially connected terminals of the plurality of power converters that form a serial connection, wherein the serial connection is connected to the direct-current-to-alternating-current inverter.

13. The method of claim 9, wherein the updating comprises updating the common voltage reference at the terminals of the plurality of power converters that are connected in parallel to form a parallel connection, wherein the parallel connection is connected to the direct-current-to-alternating-current inverter.

14. The method of claim 8, further comprising:

monitoring a plurality of fuel gauges respectively connected one-to-one to each of the plurality of energy storage devices,

wherein the determining of the respective charge fraction for each of the plurality of energy storage devices is based on the monitoring of the plurality of fuel gauges.

15. A system comprising:

an energy storage device;

fuel gauge circuitry configured to determine a charge fraction for the energy storage device;

a power converter comprising first terminals connected to the energy storage device;

an inverter comprising;

second terminals connected to the power converter, and

third terminals connected to an electrical network; and

a central controller configured to adjust, based on the charge fraction for the energy storage device determined by the fuel gauge circuitry, a voltage conversion ratio for the energy storage device such that the energy storage device completes charging or discharging at a substantially common time as another energy storage device connected to the electrical network.

16. The system of claim 15, wherein the central controller is configured to set a voltage reference or a current reference at the second terminals of the inverter.

17. The system of claim 16, wherein the voltage conversion ratio for the energy storage device is based on:

the charge fraction for the energy storage device, and

the voltage reference or the current reference.

18. The system of claim 17, wherein the central controller is configured to adjust the voltage reference or the current reference based on:

one or more sets of operating conditions of the power converter, wherein the one or more sets of operating conditions comprise buck mode, boost mode, temperature, voltage, current, or duty cycle, and

a predetermined compensation factor for the energy storage device.

19. The system of claim 18, wherein the central controller is configured to adjust the voltage reference or the current reference based on:

multiple efficiency values that respectively correspond to the one or more sets of operating conditions, wherein the multiple efficiency values are stored in a memory operatively attached to the central controller.

20. The system of claim 17, wherein the power converter is configured to transfer power from the energy storage device and to the electrical network, or from the electrical network and to the energy storage device, with variable rates such that the energy storage device reaches a respective charged or discharged level at predetermined end times.