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Active damping control method and system for a weak grid lcl inverter

A damping control and inverter technology, applied in electrical components, circuit devices, AC network circuits, etc., can solve the problems of not taking into account the adverse effects of large-scale grid impedance changes, complex parameter settings, etc., and achieve good robustness and reliability. Dynamic responsiveness, improved phase margin, reduced usage effects

Active Publication Date: 2021-08-17
SICHUAN UNIV
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  • Application Information

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Problems solved by technology

However, it does not take into account the adverse effects of large-scale grid impedance changes
In addition, there are literatures that add a simple HPF in the capacitor voltage feed-forward (CVF) loop, which effectively reduces the low-frequency harmonic pollution of the grid voltage controlled by the ICF, but the parameter setting is complicated

Method used

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  • Active damping control method and system for a weak grid lcl inverter
  • Active damping control method and system for a weak grid lcl inverter
  • Active damping control method and system for a weak grid lcl inverter

Examples

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Effect test

Embodiment 1

[0067] Embodiment 1: An active damping control method for a weak grid LCL inverter, such as Figure 1-Figure 3 shown, including the following steps:

[0068] S1: Collect the voltage signal of the grid-connected point;

[0069] S2: The voltage signal is used as the input of the high-pass filter compensation strategy to obtain active damping parameters;

[0070] S3: Taking the active damping parameters and phase margin compensation coefficient sequence as the input of active damping control, the open-loop Bode diagram of the system under the control of different phase margin compensation coefficients is obtained by simulation;

[0071] S4: Extract the open-loop cut-off frequency and the distribution of the open-loop cut-off frequency and phase margin in the open-loop Bode diagram of the system, and use the corresponding phase margin under the optimal condition of the weak grid stability and dynamic response reflected by the distribution The degree compensation coefficient is u...

Embodiment 2

[0102] Embodiment 2: An active damping control system for a weak grid LCL inverter, such as Figure 17 As shown, it includes a data acquisition module, a parameter calculation module, a simulation calculation module, a coefficient analysis module, a data fusion module, and a signal superposition module. The data acquisition module is used to collect the voltage signal of the grid-connected point; the parameter calculation module is used to use the voltage signal as the input of the high-pass filter compensation strategy to obtain the active damping parameters; the analog calculation module is used to calculate the active damping parameters, phase margin The degree compensation coefficient sequence is used as the input of the active damping control, and the system open-loop Bode diagram under the control of different phase margin compensation coefficients is simulated; the coefficient analysis module is used to extract the open-loop cut-off frequency and The distribution of ope...

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Abstract

The invention discloses a method and system for active damping control of an LCL inverter in a weak power grid, and relates to the technical field of grid-connected inverters. The key points of the technical solution are: the voltage signal is used as the input of a high-pass filter compensation strategy to obtain active damping Parameters; the active damping parameters and phase margin compensation coefficient sequence are used as the input of active damping control, and the system open-loop Bode diagram is obtained by simulation; the open-loop cut-off frequency and the open-loop cut-off frequency and the The distribution of the phase margin, and select the optimal phase margin compensation coefficient; after the optimal phase margin compensation coefficient is fused with the active damping parameters, the leading phase compensation signal is obtained; the leading phase compensation signal is combined with the multi-resonance control The active damping control of the LCL inverter is realized after the output signal of the inverter is superimposed. The invention improves the phase margin when the system is connected to the grid, reduces the use of high-precision sensors, and has good robustness and dynamic response capability.

Description

technical field [0001] The invention relates to the technical field of grid-connected inverters, more specifically, it relates to an active damping control method and system for a weak grid LCL inverter. Background technique [0002] With the increasing shortage of fossil energy, the development of renewable clean energy has become the focus of current energy development. Grid-connected inverters play an important role as the connection hub between clean energy power generation systems and the grid. Compared with the L filter, the LCL filter has the advantages of small size and strong attenuation ability, which makes it widely used in grid-connected inverters. However, LCL filter is a third-order system, if there is no certain damping strategy, it will cause resonance problems of the system, and even make the system unstable. [0003] The damping method of LCL filter can be divided into active damping and passive damping. Passive damping provides excellent damping, but ca...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/38H02J3/01H02J3/24
CPCH02J3/01H02J3/38H02J3/241H02J2203/20Y02E40/40
Inventor 曾成碧王翰文苗虹段述江李苏丹童广朱胤杰
Owner SICHUAN UNIV
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