Parallel connected inverters

• US 9,407,161 B2
• Filed: 11/05/2013
• Issued: 08/02/2016
• Est. Priority Date: 12/05/2007
• Status: Active Grant

• Current Assignee: Solaredge Limited, Solaredge Technologies Incorporated
• Original Assignee: Solaredge Technologies Incorporated
• Inventors: Adest, Meir, Sella, Guy, Handelsman, Lior, Galin, Yoav, Fishelov, Amir, Gazit, Meir, Glovinski, Tzachi, Binder, Yaron
• Primary Examiner(s): BERHANE, ADOLF D
• Application Number:
  US14/071,780
• Publication Number:
  US 20140119075A1
• Time in Patent Office: 1,001 Days
• Field of Search: 363/65, 363/71, 363/72
• US Class Current: 1/1
• CPC Class Codes: G01S 3/7861 Solar tracking systems
• CPC Class Codes: H02J 2300/10 The dispersed energy generation being of fossil origin, e.g. diesel generators
• 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 3/381 Dispersed generators
• CPC Class Codes: H02J 3/388 Islanding, i.e. disconnection of local power supply from the network
• CPC Class Codes: H02J 3/46 Controlling of the sharing of output between the generators, converters, or transformers
• CPC Class Codes: H02M 1/0077 Plural converter units whose outputs are connected in series
• CPC Class Codes: H02M 7/44 by static converters
• CPC Class Codes: H02M 7/493 the static converters being arranged for operation in parallel
• CPC Class Codes: Y02E 10/52 PV systems with concentrators
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

A distributed power system wherein a plurality of power converters are connected in parallel and share the power conversion load according to a prescribed function, but each power converter autonomously determines its share of power conversion. Each power converter operates according to its own power conversion formula/function, such that overall the parallel-connected converters share the power conversion load in a predetermined manner.

Claims

1. A method comprising equilibrating a power converter'"'"'s input voltage by adjusting the power converter'"'"'s input current to a new input current based on the power converter'"'"'s input voltage according to a specified range of input currents and to a corresponding specified range of input voltages, wherein each input current in the specified range of input currents corresponds to a predetermined input voltage in the corresponding specified range of input voltages.

2. The method of claim 1, further comprising adjusting the power converter'"'"'s input current according to the specified range of the input currents, which decreases as the corresponding specified range of the input voltages decreases.

3. The method of claim 1, further comprising reducing the power converter'"'"'s input current until a specified input current and a corresponding specified input voltage are reached.

4. The method of claim 1, wherein a non-zero input voltage value in the corresponding specified range of input voltages corresponds to a zero current value in the specified range of input currents.

5. The method of claim 1, wherein the equilibrating of the power converter'"'"'s input voltage includes adjusting the input current in response to changes in the input voltage until the power converter'"'"'s input current and the power converter'"'"'s input voltage match a specified input current and a corresponding specified input voltage.

6. The method of claim 1, further comprising specifying the range of input currents and the corresponding range of input voltages according to a plurality of power output levels of a power source providing the power converter'"'"'s input current and the power converter'"'"'s input voltage.

7. The method of claim 1, further comprising specifying the range of input currents and the corresponding range of input voltages to equilibrate the power converter'"'"'s input voltage for a power source that would increase the power converter'"'"'s input voltage in response to a reduction in the input current.

8. The method of claim 1, further comprising converting the new input current and the power converter'"'"'s input voltage to output power at an output of the power converter.

9. A method comprising

equilibrating a power converter'"'"'s input voltage by adjusting the power converter'"'"'s input current according to a specified range of the input current and to a corresponding specified range of the input voltage;

and

equilibrating the power converter'"'"'s input voltage by adjusting a second input current to a second power converter according to a second specified range of the second input current corresponding to the specified range of the input voltage, the second power converter connected in parallel with the power converter.

10. The method of claim 9, wherein the specified range of the input current and the second specified range of the second input current are the same.

11. An apparatus comprising a controller configured to:

receive a voltage signal and a current signal indicative of a power converter'"'"'s input voltage and input current respectively; and

equilibrate the power converter'"'"'s input voltage by adjusting the power converter'"'"'s input current based on the voltage signal indicative of the power converter'"'"'s input voltage according to a specified range of input currents and to a corresponding specified range of input voltages, wherein each input current in the specified range of input currents corresponds to a predetermined input voltage in the corresponding specified range of input voltages.

12. The apparatus of claim 11, wherein the controller is configured to specify the range of input currents to decrease as the corresponding specified range of input voltages decreases.

13. The apparatus of claim 11, wherein the controller is further configured to adjust the power converter such that the power converter'"'"'s input current is reduced until a specified input current and a corresponding specified input voltage are reached.

14. The apparatus of claim 11, wherein a non-zero input voltage value in the corresponding specified range of input voltages corresponds to a zero current value in the specified range of input currents.

15. The apparatus of claim 11, wherein the controller is configured to equilibrate the power converter'"'"'s input voltage by adjusting the power converter'"'"'s input current in response to changes in the power converter'"'"'s input voltage until the power converter'"'"'s input current and the power converter'"'"'s input voltage match a specified input current and a corresponding specified input voltage.

16. The apparatus of claim 11, wherein the controller is configured to specify the range of input currents and the corresponding range of input voltages according to a plurality of power output levels of a power source providing the power converter'"'"'s input current and the power converter'"'"'s input voltage.

17. The apparatus of claim 11, wherein the controller is configured to specify the specified range of input currents and the corresponding specified range of input voltages to equilibrate the power converter'"'"'s input voltage for a power source that would increase the power converter'"'"'s input voltage in response to a reduction in the power converter'"'"'s input current.

18. The apparatus of claim 11, wherein the power converter is configured to convert the power converter'"'"'s input current and the power converter'"'"'s input voltage to output power at an output of the power converter, wherein the power converter is an inverter.

19. The apparatus of claim 11, further comprising a second controller configured to equilibrate the power converter'"'"'s input voltage by adjusting a second input current to a second power converter according to a second specified range of second input currents corresponding to the specified range of input voltages, the second power converter connected in parallel with the power converter.

20. The apparatus of claim 19, wherein the specified range of input currents and the second specified range of second input currents are the same.