Fractional phase compensation control method and device for LCL grid-connected inverter under weak power grid

A phase compensation and control method technology, applied in the direction of electrical components, circuit devices, AC network circuits, etc., can solve problems such as complex structure of fractional phase compensation strategy, reduction of grid-connected current quality, system phase over-compensation, etc., to achieve suppression of grid harmonics wave and periodic disturbance, improve the quality of grid-connected current, and the effect of simple control structure

Active Publication Date: 2021-10-19
SICHUAN UNIV
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  • Application Information

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Problems solved by technology

[0006] In order to solve the poor dynamic performance of the grid-connected inverter control under the weak grid, the integer phase compensation will easily cause the phase over-compensation or under-compensation of the entire system, further reduce the quality of the grid-connected current and even cause system instability. At the same time, the current fractional phase compensation strategy has a complicated structure , large memory consumption, etc.

Method used

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  • Fractional phase compensation control method and device for LCL grid-connected inverter under weak power grid
  • Fractional phase compensation control method and device for LCL grid-connected inverter under weak power grid
  • Fractional phase compensation control method and device for LCL grid-connected inverter under weak power grid

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Embodiment 1

[0044] Such as figure 1 As shown, this embodiment provides a fractional phase compensation control method for an LCL grid-connected inverter under a weak grid, which includes the following steps:

[0045] 1. Obtain the voltage signal at the common coupling point in the inverter system and the grid-connected current signal respectively through the voltage sampling board and the current sampling board;

[0046] 2. The voltage signal obtained through the voltage sampling board passes through the phase-locked loop to extract the voltage phase angle information; according to the voltage phase angle information and the grid-connected current amplitude required by the inverter system, the grid-connected current reference in the control system is generated Signal;

[0047] 3. The grid-connected current signal obtained through the current sampling board is divided into two routes, one route passes through the grid-connected current feedback active damping to suppress the inherent reso...

Embodiment 2

[0072] This embodiment provides a fractional phase compensation control method for an LCL grid-connected inverter under a weak grid, including the following steps:

[0073] 1. Obtain the voltage signal at the common coupling point in the inverter system and the grid-connected current signal respectively through the voltage sampling unit 101 and the current sampling unit 102, see figure 2 ;

[0074] 2. The voltage signal at the common coupling point and the grid-connected current signal pass through the first coordinate system transformer 103 and the second The coordinate system converter 104 transforms the three-phase signal into a two-phase signal;

[0075] 3. Pass the second The voltage signal transformed by the coordinate system converter 104 passes through the phase-locked loop PLL105 to extract the voltage phase angle information; according to the phase angle information of the voltage signal and the grid-connected current amplitude required by the inverter syste...

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Abstract

The invention relates to the technical field of grid-connected inverter control, and relates to a fractional phase compensation control method and device for an LCL grid-connected inverter under a weak power grid. The method comprises the steps: 1, respectively obtaining a voltage signal and a grid-connected current signal; 2, extracting voltage phase angle information; and generating a grid-connected current reference signal in the control system; 3, dividing the obtained grid-connected current signal into two paths, feeding back an inherent harmonic peak of an active damping suppression LCL grid-connected inverter through the grid-connected current, obtaining an error signal by subtracting the other path from the grid-connected current reference signal, and transmitting the error signal to a current controller for modulation; 4, after the error signal is modulated by a current controller, subtracting the error signal from a grid-connected current feedback active damping signal to obtain a modulated wave signal; and 5, comparing to obtain a control signal. The current controller structure is a proportional resonance parallel repetitive control structure with a fractional phase compensation function, the design is simple, and flexible fractional phase compensation can be provided under a weak power grid.

Description

technical field [0001] The invention relates to the technical field of grid-connected inverter control, in particular to a fractional phase compensation control method and equipment for an LCL grid-connected inverter under a weak grid. Background technique [0002] Distributed energy is mainly installed in remote areas with small power loads. In order to transmit electric energy to the power load center, it needs to go through long-distance transmission lines. At this time, the grid line impedance cannot be ignored, and the power grid has the characteristics of a weak grid. Under a weak grid, the grid-connected current harmonics will be further amplified, and in more serious cases, the inverter system will be unstable. [0003] As the key equipment for grid-connected distributed energy, the control strategy of grid-connected inverters has been extensively studied. At present, a variety of controllers have been used in the control of grid-connected inverters, such as proport...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02J3/01H02J3/24
CPCH02J3/381H02J3/01H02J3/241H02J2203/20Y02E40/40
Inventor 曾成碧李苏丹苗虹王翰文段述江童广朱胤杰
Owner SICHUAN UNIV
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