System and method for establishing communication with an array of inverters

• US 10,033,221 B2
• Filed: 10/01/2015
• Issued: 07/24/2018
• Est. Priority Date: 10/11/2010
• Status: Active Grant

• Current Assignee: Enphase Energy Incorporated
• Original Assignee: Sunpower Corporation (Totalenergies Se)
• Inventors: Krohne, Edward, Kuhn, Brian T.
• Primary Examiner(s): Barnie, Rexford
• Assistant Examiner(s): Mourad, Rasem
• Application Number:
  US14/872,886
• Publication Number:
  US 20160020827A1
• Time in Patent Office: 1,027 Days
• CPC Class Codes: H02J 13/00007 using the power network as support for the transmission
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/46 Controlling of the sharing of output between the generators, converters, or transformers
• CPC Class Codes: H02M 7/42 Conversion of dc power input into ac power output without possibility of reversal
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines
• CPC Class Codes: H04B 3/544 Setting up communications; Call and signalling arrangements
• CPC Class Codes: H04B 3/548 the power on the line being DC arrangements for feeding power H04L12/10; extracting feeding power from signals H04L25/02
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y02E 40/70 Smart grids as climate change mitigation technology in the energy generation sector
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 10/123 the energy generation units being or involving renewable energy sources
• CPC Class Codes: Y04S 40/121 using the power network as support for the transmission

Abstract

A system and method for establishing communication between a controller and a plurality of inverters comprises determining a response time window length and broadcasting a response request to the array of inverters that includes the response time window length. Each inverter, in response to receiving the response requests, transmits a response to the controller at a randomly determined response time within the response time window. In response to receiving an acknowledgement from the controller, the responding inverter may ignore subsequent response requests. The controller may adjust the response time window and broadcasts the new response time window until no inverter response is received for a pre-determined number of response time windows.

Claims

1. A method for communication between a controller and a plurality of inverters, the inverters configured to convert direct current (DC) power from an alternative energy source to AC power, the method comprising:

receiving with a first inverter a response request transmitted by the controller, the response request including a length of a response time window;

determining a random response time for the first inverter based on the length of the response time window;

transmitting a response to the controller at the response time, the response including an identification of the first inverter;

storing an identification of the responding first inverter for use by the controller in computer readable memory, the stored identification uniquely identifying the first inverter from other inverters of the plurality of inverters; and

in response to receiving an acknowledgement from the controller in response to the transmitted response, ignoring subsequent response requests from the controller,

the first inverter and the other inverters of the plurality of inverters connected in a wired array arrangement, the wired array arrangement comprising an AC output power line and transmitting AC power generated by one or more of the plurality of inverters, via the wired array arrangement.

2. The method of claim 1, wherein receiving a response request comprises receiving a response request that was broadcast from the controller over an alternating current (AC) power line using a power line communication protocol.

3. The method of claim 1, wherein determining a response time comprises determining a response time that is within the response time window.

4. The method of claim 3, wherein determining a random response time comprises determining a random response time that is a multiple of the length of time required by the first inverter to transmit a response to the response request to the controller.

5. The method of claim 1, wherein ignoring subsequent response requests comprises ignoring subsequent response requests from the controller for a predetermined amount of time.

6. The method of claim 1, wherein ignoring subsequent response requests comprises ignoring subsequent response requests from the controller until a communication from the controller is received that instructs the first inverter to stop ignoring subsequent response requests.

7. The method of claim 1, further comprising:

in response to (i) not receiving an acknowledgement from the controller in response to the transmitted response and (ii) receiving a subsequent response request from the controller that includes a length of a subsequent response time window;

determining a subsequent response time for the first inverter based on the length of the subsequent response time window; and

transmitting a response to the controller at the response time, the response including the identification of the first inverter,

wherein the stored identification is used by the controller to identify the first inverter and directly communication with the first inverter.

8. An inverter to convert direct current (DC) power from an alternative energy source to alternating current (AC) power, the inverter comprising:

a communication circuit to communicate with a controller over an AC power line using a power line communication protocol, the AC power line receiving AC power from the inverter;

a processor communicatively coupled to the communication circuit; and

a memory device communicatively coupled with the processor and having stored therein a plurality of instructions, which when executed by the processor, result in the processor;

receiving a response request transmitted by the controller over the AC power line, the response request including a length of a response time window;

determining a random response time for the inverter based on the length of the response time window;

transmitting a response to the controller at the response time, the response including an identification of the inverter; and

in response to receiving an acknowledgement from the controller in response to the transmitted response, updating the inverter'"'"'s operation in order to ignore subsequent response requests from the controller.

9. The inverter of claim 8, wherein receiving a response request comprises receiving a response request that was broadcast from the controller over an alternating current (AC) power line using a power line communication protocol.

10. The method of claim 8, wherein determining a random response time comprises determining a random response time that is a multiple of the length of time required by the inverter to transmit a response to the response request to the controller.

11. The inverter of claim 8, wherein ignoring subsequent response requests comprises ignoring subsequent response requests from the controller for a predetermined amount of time.

12. The inverter of claim 8, wherein ignoring subsequent response requests comprises ignoring subsequent response requests from the controller until a communication from the controller is received that instructs the inverter to stop ignoring subsequent response requests.

13. The inverter of claim 8, wherein the plurality of instructions further cause the inverter to:

in response to (i) not receiving an acknowledgement from the controller in response to the transmitted response and (ii) receiving a subsequent response request from the controller that includes a length of a subsequent response time window;

determining a subsequent response time for the inverter based on the length of the subsequent response time window; and

transmitting a response to the controller at the response time, the response including the identification of the inverter.

14. One or more non-transitory machine-readable media comprising a plurality of instructions stored thereon that, in response to execution by an inverter configured to convert direct current (DC) power from an alternative energy source to alternating current (AC) power and transmit the AC power via a wired connection to an electrical load, causes the inverter to:

receive a response request transmitted by a controller, the response request including a length of a response time window;

determine a random response time for the inverter based on the length of the response time window;

transmit a response to the controller at the response time, the response including an identification of the inverter; and

update its own operation in order to ignore subsequent response requests from the controller in response to receipt of an acknowledgement from the controller received in response to the transmitted response.

15. The one or more non-transitory machine-readable media of claim 14, wherein to receive the response request comprises to receive a response request that was broadcast from the controller over an AC power line using a power line communication protocol.

16. The one or more non-transitory machine-readable media of claim 14, wherein to determine the random response time comprises to determine a random response time that is within the response time window.

17. The one or more non-transitory machine-readable media of claim 16, wherein to determine the random response time comprises to determine a random response time that is a multiple of the length of time required by the inverter to transmit a response to the response request to the controller.

18. The one or more non-transitory machine-readable media of claim 14, wherein to ignore the subsequent response requests comprises to ignore subsequent response requests from the controller for a predetermined amount of time.

19. The one or more non-transitory machine-readable media of claim 14, wherein to ignore the subsequent response requests comprises to ignore subsequent response requests from the controller until a communication from the controller is received that instructs the inverter to stop ignoring subsequent response requests.

20. The one or more non-transitory machine-readable media of claim 14, wherein the plurality of instructions further causes the inverter, in response to (i) not receiving an acknowledgement from the controller in response to the transmitted response and (ii) receiving a subsequent response request from the controller that includes a length of a subsequent response time window, to:

determine a subsequent response time for the inverter based on the length of the subsequent response time window; and

transmit a response to the controller at the response time, the response including the identification of the inverter.