Inverter communications using output signal

• US 9,564,835 B2
• Filed: 04/26/2013
• Issued: 02/07/2017
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Enphase Energy Incorporated
• Original Assignee: Sunpower Corporation (Totalenergies Se)
• Inventors: Chapman, Patrick L.
• Primary Examiner(s): Han, Jessica
• Assistant Examiner(s): Gibson, Demetries A
• Application Number:
  US13/871,169
• Publication Number:
  US 20140268958A1
• Time in Patent Office: 1,383 Days
• Field of Search: 363/97, 363/15, 363/17, 363/109, 363/51, 363/35, 363/21.02, 363/40, 363/98, 363/132, 363/131, 363/41, 323/247, 323/207, 323/906
• US Class Current: 1/1
• CPC Class Codes: H02J 1/102 being switching converters H02J1/108, H02J1/12 take precedence
• CPC Class Codes: H02J 13/00009 using pulsed signals
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 3/00 Circuit arrangements for ac mains or ac distribution networks
• 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 3/40 Synchronising a generator for connection to a network or to another generator
• CPC Class Codes: H02M 1/084 using a control circuit common to several phases of a multi-phase system
• CPC Class Codes: H02M 7/44 by static converters
• CPC Class Codes: H02M 7/5395 by pulse-width modulation
• CPC Class Codes: H02M 7/81 arranged for operation in parallel
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines
• 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 10/76 Power conversion electric or electronic aspects
• 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

Technologies for communicating information from an inverter configured for the conversion of direct current (DC) power generated from an alternative source to alternating current (AC) power are disclosed. The technologies include determining information to be transmitted from the inverter over a power line cable connected to the inverter and controlling the operation of an output converter of the inverter as a function of the information to be transmitted to cause the output converter to generate an output waveform having the information modulated thereon.

Claims

1. A method for communicating information from a plurality of inverters configured for the conversion of direct current (DC) power generated from alternative sources to alternating current (AC) power, wherein each inverter of the plurality of inverters includes (i) an input converter to receive a DC power input from a source, (ii) an output converter coupled to a power line cable to supply an AC power output of the corresponding inverter to a power grid, and (iii) an inverter controller to control operation of the corresponding input converter and output converter, the method comprising:

determining, in a first inverter of the plurality of inverters, first information to be transmitted from the first inverter to a remote device over a power line cable connected to the first inverter;

determining, in a second inverter of the plurality of inverters, second information to be transmitted from the second inverter to the remote device over a power line cable connected to the second inverter;

generating, in the first inverter, an output waveform of the first inverter having a carrier signal;

generating, in the second inverter, an output waveform of the second inverter having the carrier signal;

shifting, in the first inverter, a frequency of the carrier signal by a first amount to modulate the first information on the carrier signal; and

shifting, in the second inverter, the frequency of the carrier signal by a second amount different from the first amount to modulate the second information on the carrier signal.

2. The method of claim 1, wherein shifting, in the first inverter, the frequency comprises shifting, in the first inverter, the frequency by a first amount less than an original frequency of the carrier signal and shifting, in the first inverter, the frequency by a second amount greater than the original frequency of the carrier signal.

3. The method of claim 1, further comprising:

detecting whether the first inverter has been disconnected from a power grid;

detecting whether a maintenance tool has been communicatively coupled to the power line cable; and

communicating with the maintenance tool using a data transfer rate higher than a data transfer rate of the output waveform of the first inverter having the first information modulated thereon.

4. The method of claim 1, further comprising detecting the first information modulated on the output waveform using a current sensor coupled to the power line cable.

5. The method of claim 4, further comprising demodulating the first information from the carrier signal of the output waveform.

6. A system for communicating information over a power line cable, the system comprising:

a first inverter comprising a first input converter to receive a direct current (DC) power input from a solar panel, a first output converter coupled to a power line cable to supply an AC power output of the first inverter to a power grid, and a first inverter controller to control operation of the first input converter and the first output converter, and

a second inverter comprising a second input converter to receive a DC power input from a second solar panel, a second output converter coupled to the power line cable to supply an AC power output of the second inverter to the power grid, and a second inverter controller to control operation of the second input converter and the second output converter,

wherein the first inverter controller is to determine first information to be transmitted from the first inverter over the power line cable and control operation of the first output converter to shift a carrier frequency of a carrier signal of an output waveform generated by the first output converter by a first amount to modulate the first information on the carrier signal, and

wherein the second inverter controller is to determine second information to be transmitted from the second inverter over the power line cable and control operation of the second output converter to shift the carrier frequency of the carrier signal of an output waveform generated by the second output converter by a second amount different from the first amount to modulate the second information on the carrier signal.

7. The system of claim 6, wherein the output waveform generated by the first output converter comprises the modulation signal, the carrier signal, and the first information to be modulated on the carrier signal.

8. The system of claim 6, wherein the first inverter controller is to shift the frequency of the carrier signal by an amount of less than one percent of the original frequency of the carrier signal.

9. The system of claim 6, wherein the first inverter controller is to shift the frequency of the carrier signal by a first amount less than an original frequency of the carrier signal and shift the frequency by a second amount greater than the original frequency of the carrier signal.

10. The system of claim 6, further comprising a maintenance tool communicatively couplable to the power line cable,

wherein the first inverter controller is to (i) detect whether the first inverter has been disconnected from the power grid, (ii) detect whether the maintenance tool has been communicatively coupled to the power line cable, and (iii) communicate with the maintenance tool using a data transfer rate higher than a data transfer rate of the output waveform having the first information modulated thereon.

11. The system of claim 6, further comprising a current sensor coupled to the power line cable to detect the first information modulated on the output waveform.

12. The system of claim 11, further comprising an inverter array gateway communicatively coupled to the current sensor and comprising a demodulator to demodulate the first information from the carrier signal.