Backfeed power supply for solar power system

A method for operating a solar power system including a solar collection system and coupled to a power grid, the method comprising:

• measuring a DC voltage of the solar collection system,
• determining whether the DC voltage is below a threshold value;
• when the DC voltage is below the threshold, providing power from the power grid to the solar collection system;
• and
• when the DC voltage is above the threshold, not providing power from the power grid to the solar collection system.

A solar power system coupled to an AC power grid comprising:

• a solar collection system adapted to output DC power at a DC voltage;
• an inverter having an input terminal coupled to the solar collection system and an output terminal coupled to the AC power grid, the inverter including:
• one or more input controlled switches,
• an output stage,
• an inverter controller,
• a transformer having a first winding coupled to the output terminal and a second winding;
• a backfeed power supply coupled to the solar collection system, the input terminal, and the second winding of the transformer, the backfeed power supply including:
• an AC-DC converter, and
• one or more backfeed controlled switches;
• wherein the inverter controller is adapted to:
• receive the DC voltage,
• determine whether the DC voltage is below a threshold value,
• if the DC voltage is below the threshold value, deactivate the one or more input controlled switches and activate the one or more backfeed controlled switches, and
• if the DC voltage is above the threshold value, activate the one or more input controlled switches and deactivate the backfeed controlled switches,
• wherein the solar collection system receives power from the AC power grid when the one or more backfeed controlled switches are activated.