Enphase Energy, Inc.
Method and apparatus for impedance matching in virtual impedance droop controlled power conditioning units

Abstract:

A method and apparatus for setting an impedance of a power conditioning unit (PCU). In one embodiment, the method comprises applying a disturbance to a virtual AC voltage produced by a power conditioning unit (PCU) that is coupled to a power grid, where the disturbance has a first phase; measuring a second phase of the applied disturbance on the power grid; comparing the second phase of the applied disturbance to the first phase of the disturbance; and adjusting, when the second phase differs from the first phase by more than a threshold amount, an impedance of the PCU.