Method and apparatus for storing and depleting energy

• US 9,548,619 B2
• Filed: 03/14/2013
• Issued: 01/17/2017
• 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): Fureman, Jared
• Assistant Examiner(s): Baxter, Brian K
• Application Number:
  US13/803,212
• Publication Number:
  US 20140265606A1
• Time in Patent Office: 1,405 Days
• Field of Search: 307/82
• US Class Current: 1/1
• 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 connectible 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:

transferring power from an electrical network to a plurality of energy storage devices using a plurality of power converters such that the energy storage devices reach predetermined charge values at a common charging end time; and

transferring power from the plurality of energy storage devices to the electrical network using the plurality of power converters, such that the energy storage devices reach predetermined depletion values at a common discharging end time, the plurality of power converters each having first terminals that connect the plurality of power converters one-to-one to the plurality of energy storage devices, and the plurality of power converters each having second terminals connected to the electrical network.

2. The method of claim 1, further comprising:

controlling, responsive to a common voltage reference or a common current reference at the second terminals, each of the plurality of power converters to independently regulate charging and discharging the energy storage devices with a plurality of variable energy charge and discharge rates.

3. The method of claim 2, the energy storage devices comprising batteries, the method further comprising:

determining a battery charge fraction respectively for each of the batteries; and

maintaining, independently for each of the batteries, a respective voltage conversion ratio based on the respective battery charge fraction for each of the batteries, wherein the charging is complete for the batteries at the common charging end time responsive to the common voltage reference or the common current reference, and the discharging is complete for the batteries at the common discharging end time responsive to the common voltage reference or the common current reference.

4. The method of claim 3, further comprising, during the charging, maintaining the respective voltage conversion ratio proportional to a reciprocal of an amount of additional charge that may be stored in each of the batteries.

5. The method of claim 3, further comprising, during the discharging, maintaining the respective voltage conversion ratio proportional to a reciprocal of a remaining available charge in each of the batteries.

6. The method of claim 3, wherein the batteries are arranged in a first bank of batteries and a second bank of batteries and the method further comprising:

locating the first bank of batteries and the second bank of batteries in different geographic locations, wherein the first bank of batteries and the second bank of batteries share the common voltage reference or the common current reference.

7. The method of claim 2, further comprising:

setting the common voltage reference or the common current reference using an alternating-current-to-direct-current inverter, the common voltage reference or the common current reference being set at DC terminals of the alternating-current-to-direct-current inverter.

8. The method of claim 7, further comprising:

providing a value of the common voltage reference or the common current reference using a central controller attached to the alternating-current-to-direct-current inverter.

9. The method of claim 2, the plurality of power converters being serially connected at the second terminals to form a serial connection, the serial connection being connected to the electrical network, and the controlling being responsive to the common current reference.

10. The method of claim 2, the power converters being parallel connected at the second terminals and the controlling being responsive to the common voltage reference.

11. A system comprising:

a plurality of power converters each including first terminals that connect one-to-one the plurality of power converters to batteries, and each including second terminals that are connected to a direct current source of power and correspond to a common voltage reference or a common current reference, each of the power converters including a fuel gauge circuitry configured to determine a battery charge fraction for each of the batteries and to independently maintain a voltage conversion ratio for each of the batteries based on the battery charge fraction such that the batteries reach predetermined charge values substantially at a common charging end time responsive to the common voltage reference or the common current reference.

12. The system of claim 11, wherein the plurality of power converters are serially connected at the second terminals and the common charging end time is responsive to the common current reference set at the second terminals of the power converters.

13. The system of claim 11, wherein the plurality of power converters are parallel connected at the second terminals and the common charging end time is responsive to the common voltage reference set across a parallel connection of the second terminals of the power converters.

14. The system of claim 11, further comprising:

an alternating-current-to-direct-current inverter including alternating-current terminals and direct-current terminals, wherein the alternating-current terminals are connected to an alternating-current electrical network source of power, wherein the direct-current terminals are operatively attached to the second terminals of the plurality of power converters, wherein the alternating-current-to-direct-current inverter includes a control portion configured to set the common voltage reference or the common current reference through the direct-current terminals.

15. The system of claim 14, further comprising a central controller operatively attached to the alternating-current-to-direct-current inverter to provide a value for the common voltage reference or the common current reference.

16. The system of claim 11, wherein the fuel gauge circuitry is configured to transfer power such that the batteries reach a discharged state substantially at a common discharging end time responsive to the common voltage reference or the common current reference.

17. A system comprising:

energy storage devices;

a common voltage reference or a common current reference;

fuel gauge circuitry configured to determine an energy storage fraction respectively for the energy storage devices; and

power converters coupled one-to-one through respective first terminals to the energy storage devices, each power converter configured to independently maintain a voltage conversion ratio, based on the energy storage fraction for the energy storage device to which the power converter is connected, wherein the power converters are configured to store energy in the energy storage devices independently with a plurality of variable rates of energy storage such that the energy storage devices reach predetermined charge values substantially at a common charging end time responsive to the common voltage reference or the common current reference.

18. The system of claim 17, wherein the power converters are configured to deplete energy from the energy storage devices independently with a plurality of variable energy depletion rates such that the energy storage devices become depleted at a common discharging end time responsive to the common voltage reference or the common current reference.

19. The system of claim 18, further comprising:

an alternating-current-to-direct-current inverter configured to set the common voltage reference or the common current reference at DC terminals of the alternating-current-to-direct-current inverter, wherein the alternating-current-to-direct-current inverter is connected to second terminals of each of the power converters.

20. The system of claim 19, wherein the power converters are serially connected at the second terminals to form a serial connection to the alternating-current-to-direct-current inverter, and the alternating-current-to-direct-current inverter is configured to set the common current reference.