Inverter communications using output signal

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.