US 11,901,730 B2
Grid impedence estimation for power converter controller
Gernot Herbst, Chemnitz (DE); Daniel Kloeser, Eckernförde (DE); Xiaofan Wu, North Brunswick, NJ (US); and Ulrich Muenz, Princeton, NJ (US)
Assigned to Siemens Aktiengesellschaft, Munich (DE)
Appl. No. 17/262,776
Filed by Siemens Aktiengesellschaft, Munich (DE)
PCT Filed Aug. 20, 2018, PCT No. PCT/US2018/047076
§ 371(c)(1), (2) Date Jan. 25, 2021,
PCT Pub. No. WO2020/040724, PCT Pub. Date Feb. 27, 2020.
Prior Publication US 2021/0313833 A1, Oct. 7, 2021
Int. Cl. H02J 13/00 (2006.01); G01R 27/16 (2006.01)
CPC H02J 13/00002 (2020.01) [G01R 27/16 (2013.01); H02J 2203/20 (2020.01)] 15 Claims
OG exemplary drawing
 
1. A system for estimation of grid impedance in a power converter controller, comprising:
a processor for executing program modules of a system memory;
the system memory having program modules comprising:
a current controller configured to inject an injection current while operating online and coupled to a power grid at a point of common coupling (PCC), the injection current being benign to an operating current of the power converter;
a voltage controller configured to regulate input voltage of the power converter; and
an impedance module configured to:
determine parameters for the injection current including injection interval and duration, current magnitude, current frequency, and symmetrical component;
extract measurements of current and voltage at the PCC at an operating point shifted from a previous operating point in response to the injection current;
extract symmetrical components of current and voltage measurements; and
compute an estimated grid impedance based on the extracted symmetrical components.