Multi-loop control parameter identification method and system of grid-connected inverter

Abstract

The invention provides a multi-loop control parameter identification method and system for a grid-connected inverter. The multi-loop control parameter identification method comprises the following steps of acquiring a circuit element parameter group W; determining a plurality of groups of steady-state operation point parameter groups O and impedance value sequences under a plurality of groups of steady-state operation points based on the conventional operation condition range of the grid-connected inverter; and performing control parameter fitting on the parameter group, the impedance numerical value sequence and the circuit element parameter group under each group of steady-state operation points based on an impedance / admittance model of the inverter to obtain control group parameters; fitting precision of different loop control parameters is improved by adopting a frequency band-by-frequency band fitting mode, influences of different steady-state operation points on impedance characteristics of the inverter and influences of phase-locked control and direct-current bus voltage control frequency band superposition are considered, and applicability of parameter fitting is improved;a problem of accurate modeling caused by black / gray box control of an actual grid-connected inverter is solved; and the obtained amplitude-frequency curve and phase-frequency curve of the broadband impedance of the steady-state operation point meet the analysis requirements on the characteristic mechanism of the device.

Description

technical field [0001] The invention belongs to the field of grid-connected inverter modeling, and relates to a method and system for identifying multi-loop control parameters of a grid-connected inverter. Background technique [0002] In recent years, wind, light and other new energy power generation has developed rapidly and has become an important power source for power systems. Different from traditional synchronous generator sets, new energy units such as wind and light are mostly connected to the grid for power generation through power electronic inverters. Therefore, the control characteristics of new energy units are mainly determined by the control method and parameters of the grid-connected inverter. [0003] As the installed capacity of new energy power generation in the power system continues to increase, its control characteristics have brought increasingly profound changes to the dynamic characteristics of the power system. In regional power grids where new ene...

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Problems solved by technology

[0008] In view of the dynamic characteristics of the existing grid-connected inverters, the characteristics are complex; the control method of the grid-connected inverter has a typical scheme in theory, but the control method and parameters adopted by the actual device have the problem of "black / grey box" , cannot be obtained accurately, and based on the impedance scanning of the controller-in-the-loop simulation, the impedance obtained by scanning is a characteristic curve composed of discrete values, which can realize general qualitative analysis and is difficult to meet the analysis requirements of the device characteristic mechanism. , the present invention provides a multi-loop control parameter identification method and system for grid-connected inverters, including:

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