Parallel connected inverters

• US 9,979,280 B2
• Filed: 06/16/2016
• Issued: 05/22/2018
• Est. Priority Date: 12/05/2007
• Status: Active Grant

• Current Assignee: 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
• Application Number:
  US15/184,040
• Publication Number:
  US 20170141679A1
• Time in Patent Office: 705 Days
• Field of Search: 363 65, 363 71, 363 72
• CPC Class Codes: G01S 3/7861 Solar tracking systems
• CPC Class Codes: H02J 13/00 Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
• 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 3/38 Arrangements for parallely feeding a single network by two or more generators, converters or transformers
• 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 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 1/0077 Plural converter units whose outputs are connected in series
• CPC Class Codes: H02M 1/08 Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
• CPC Class Codes: H02M 1/44 Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
• CPC Class Codes: H02M 3/04 by static converters
• 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: H02S 40/22 Light-reflecting or light-concentrating means directly associated with the PV cell or integrated with the PV cell H01L31/054
• 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:

receiving, by a power converter, an input voltage;

determining a new input current for the power converter based on a specified function, wherein the specified function specifies a range of input currents for the power converter to draw for a corresponding range of input voltages received at a DC input of the power converter; and

equilibrating the input voltage of the power converter by adjusting an input current of the power converter to the new input current by adjusting an input current.

2. The method of claim 1, wherein the power converter is a DC-to-DC power converter.

3. The method of claim 1, wherein the power converter is a DC-to-AC power converter.

4. A method comprising:

equilibrating a first power converter'"'"'s input voltage by adjusting an input current of the first power converter according to a first specified function, wherein the first specified function comprises a first range of the input current of the first power converter and a corresponding specified first range of the first power converter'"'"'s input voltage; and

equilibrating the first power converter'"'"'s input voltage based on an adjustment of an input current of a second power converter according to a second specified function, wherein the second specified function comprises a second range of the input current of the second power converter corresponding to a specified second range of the second power converter'"'"'s input voltage.

5. The method of claim 4 wherein the second power converter is connected in parallel with the first power converter.

6. A system comprising:

a first power converter comprising a controller, configured to adjust input current drawn by the first power converter at an input of the first power converter in response to a change in a received input voltage at the input of the first power converter until power at the input reaches an equilibrium according to a first specified function that specifies a range of input currents for the power converter to draw for a corresponding range of input voltages received at the input of the first power converter; and

a second power converter, coupled in parallel to the first power converter, comprising a controller configured to adjust input current drawn by the second power converter at an input of the second power converter in response to a change in a received input voltage at the input of the second power converter until power at the input reaches an equilibrium according to a second specified function that specifies a range of input currents for the power converter to draw for a corresponding range of input voltages received at the input of the second power converter.

7. The system of claim 6, wherein one or more energy storage devices are coupled to inputs of the first and second power converters.

8. The system of claim 7, wherein the one or more energy storage devices comprise one or more battery devices.

9. The system of claim 7, wherein the one or more energy storage devices comprise one or more of the following:

a capacitor, a fuel cell, or a super-conducting flywheel.

10. The system of claim 6, further comprising an enclosure housing the first and second power converters.

11. The system of claim 6, wherein the first power converter comprises a DC-to-DC power converter.

12. The system of claim 11, further comprising an electromagnetic interference (EMI) filter, wherein the EMI filter coupled to the input of the first power converter.

13. The system of claim 11, further comprising an EMI filter, wherein the EMI filter is coupled to an output of the first power converter.

14. An apparatus comprising:

a plurality of power converters comprising an input and an output;

an enclosure; and

one or more electromagnetic interference (EMI)/radio frequency interference (RFI) filters coupled to the output of the power converters and to the input of the power converters,

wherein the plurality of power converters are coupled in parallel,

wherein the plurality of power converters share the enclosure, and

wherein one or more of the plurality of power converters are configured for operating in a load-balancing mode.

15. The apparatus of claim 14, further comprising one or more racks, wherein the plurality of power converters is configured to be coupled to the one or more racks.

16. The apparatus of claim 14,

wherein each power converter of the plurality of the power converters comprises a control module coupled to an input and an output of a respective power converter, and

wherein each control module comprises:

(i) a voltage loop block configured to receive a voltage at the input and to compare the voltage at the input to at least one previously specified reference voltage and to output a current reference signal based on the comparison; and

(ii) a current loop block configured to receive an input current to a respective power converter and to compare said current reference signal with a current signal proportional to the input current of the respective converter to adjust the input current until an input power equilibrates.

17. An apparatus comprising:

an enclosure;

one or more electromagnetic interference (EMI)/radio frequency interference (RFI) filters; and

a plurality of power converters housed in the enclosure and coupled in parallel to each other, wherein one or more of the converters comprises;

an input;

an output; and

a control module coupled to its respective input and output, wherein the control module comprises;

a voltage loop block configured to receive a voltage at the input and to compare the voltage at the input to at least one previously specified reference voltage and to output a current reference signal based on the comparison; and

a current loop block configured to receive an input current to a respective power converter and to compare said current reference signal with a current signal proportional to the input current of the respective converter to adjust the input current until an input power equilibrates.