US 12,224,591 B2
Virtual impedance current limiting control for grid forming inverter-based resources
Philip Joseph Hart, Rexford, NY (US); and Maozhong Gong, Latham, NY (US)
Assigned to GE Infrastructure Technology LLC, Greenville, SC (US)
Filed by General Electric Company, Schenectady, NY (US)
Filed on May 16, 2022, as Appl. No. 17/744,944.
Prior Publication US 2023/0369865 A1, Nov. 16, 2023
Int. Cl. H02J 3/38 (2006.01); H02J 3/00 (2006.01)
CPC H02J 3/381 (2013.01) [H02J 3/001 (2020.01); H02J 2300/28 (2020.01)] 18 Claims
OG exemplary drawing
 
1. A method for controlling an inverter-based resource connected to a power grid during a grid event, the method comprising:
operating, via a controller, the inverter-based resource based on a first virtual impedance reference prior to the grid event, the first virtual impedance reference being used by the controller for determining a first virtual impedance of the inverter-based resource defining a first virtual reactance and a first virtual resistance;
receiving, via the controller, an indication of a start of the grid event that causes a change in the first virtual impedance reference to a second virtual impedance reference that is larger than the first virtual impedance reference;
immediately after the change in the first virtual impedance reference, activating a soft activation module for outputting a second virtual impedance defining a second virtual reactance and a second virtual resistance that maintains a magnitude of the second virtual impedance at or above a magnitude of the second virtual impedance reference so as to reduce current in the inverter-based resource;
at a certain time period after activating the soft activation module, transitioning, via the controller, the second virtual reactance and the second virtual resistance to a virtual reactance and a virtual resistance defined by the change; and
ensuring that once the soft activation module is activated, the magnitude of the second virtual impedance is maintained at or above the magnitude of the second virtual impedance reference so as to reduce current oscillations in the power grid for a duration of the grid event, wherein ensuring that once the soft activation module is activated, the magnitude of the second virtual impedance is maintained at or above the magnitude of the second virtual impedance reference further comprises:
receiving, via the controller, an activation signal; and
determining whether or not to subtract a voltage drop from a voltage reference of the inverter-based resource.