Grid-connected inverter controller bandwidth design method under weak power grid

A technology for inverters and weak grids, applied in wind power generation, single grid parallel feeding arrangements, etc., can solve problems such as instability, grid-connected inverter system instability, and no grid-connected inverter, etc. Achieve strong practical value, solve instability problems, and simple and intuitive calculation method

Active Publication Date: 2021-07-23
HEFEI UNIV OF TECH
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Problems solved by technology

[0008] 1. When analyzing the stability of the grid-connected inverter system under a weak grid, many studies only qualitatively analyzed the influence of the grid strength and the interaction between the phase-locked loop and the current inner loop on the system stability, but did not give A specific method to solve the instability problem of the grid-connected inverter under the extremely weak grid
[000...

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  • Grid-connected inverter controller bandwidth design method under weak power grid
  • Grid-connected inverter controller bandwidth design method under weak power grid
  • Grid-connected inverter controller bandwidth design method under weak power grid

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Embodiment Construction

[0041] figure 1 is the topology diagram of the grid-connected inverter in the embodiment of the present invention. like figure 1 As shown, the topology of the present invention includes a DC voltage source U dc , DC side filter capacitor C dc , three-phase half-bridge inverter, L filter and three-phase AC grid. DC voltage source U dc through the filter capacitor C dc Connected to the input terminal of the inverter, the output terminal of the inverter is connected to the three-phase AC grid through the L filter, L grid is the inductance component corresponding to the grid impedance, denoted as the grid impedance inductance component L grid . R grid is the resistance component corresponding to the grid impedance, denoted as the grid impedance resistance component R grid .

[0042] The relevant electrical parameters when the present invention is implemented are set as follows: DC voltage source U dc =750V, the rated capacity of the grid-connected inverter is 30kVA, and...

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Abstract

The invention discloses a bandwidth design method for a grid-connected inverter controller under a weak power grid and belongs to the field of power control. The bandwidth design method comprises the following steps of sampling, firstly giving a grid-connected inverter current control loop open-loop transfer function, then solving the amplitude of the current control loop open-loop transfer function, and finally giving a constraint relation between the current control loop bandwidth and the phase-locked loop bandwidth under a weak power grid by combining a Nyquist stability criterion, and parameter design of a current control loop and a phase-locked loop controller being completed. According to the method, the constraint relation and the value range of the design bandwidth of the current control loop and the bandwidth of the phase-locked loop under the weak power grid condition are quantitatively given, and a problem that a grid-connected inverter system is unstable due to interaction under the weak power grid condition can be effectively solved.

Description

technical field [0001] The invention relates to a bandwidth design method of a grid-connected inverter controller, in particular to a bandwidth design method of a grid-connected inverter controller under a weak grid, belonging to the field of electric power control. Background technique [0002] Since the 21st century, with the rapid development of various forms of power generation such as wind energy and solar energy, more and more renewable energy sources have been integrated into the large power grid through power electronic interfaces. Very weak network characteristics. The stability of the grid-connected inverter system under the weak grid is one of the most concerned and practically important issues in the stability research of the grid-connected interface system with power electronics. In an extremely weak grid system formed by a high proportion of power electronic grid-connected interfaces, the phase-locked loop and the control system usually interact to cause syste...

Claims

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Application Information

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IPC IPC(8): H02J3/38
CPCH02J3/38Y02E10/76
Inventor 刘芳刘威李研徐韫钰
Owner HEFEI UNIV OF TECH
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