An Impedance-Based Parameters Identification Method for Grid-Connected Inverter

Abstract

Aiming at the problem of “black/gray box” modeling of renewable energy grid-connected inverters, a method to determine the multi-loop control parameters of grid-connected inverter based on broadband impedance is proposed in this paper. A band-by-band fitting method is adopted to improve the fitting accuracy of different loop control parameters. The influences of steady-state operation points on the impedance characteristics of inverter and the influences of frequency overlap between PLL control and DC bus voltage control are considered, which improves the applicability of parameter fitting. It is helpful to overcome the challenge of accurate modeling caused by “black/gray box” of actual grid-connected inverter control.