Grid-connected inverter current control method based on improved repetitive controller

A repetitive controller and current control technology, applied in AC network circuits, AC power input conversion to DC power output, photovoltaic power generation, etc. Suppress grid voltage disturbance, enhance rapidity and robustness, and save cost

Inactive Publication Date: 2019-02-22
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the traditional repetitive control has an inherent fundamental cycle delay, and the dynamic response performance is poor. At the same time, the introduction of the inner membrane coefficient makes the control system have a certain steady-state error.

Method used

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  • Grid-connected inverter current control method based on improved repetitive controller
  • Grid-connected inverter current control method based on improved repetitive controller
  • Grid-connected inverter current control method based on improved repetitive controller

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Embodiment Construction

[0036] The present invention will be described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited by the accompanying drawings.

[0037] figure 1 It is a system structure diagram of the present invention, as shown in the figure, the main circuit parameters of the system include: DC side voltage U dc =400V; inverter side inductance L1=1mH; grid side inductance L2=0.5mH; filter capacitor C=20μF; sampling frequency f s = 10kHz. The system control module includes: dq / αβ, abc / αβ and αβ / abc coordinate system conversion modules, improved repeat control module, grid voltage feedforward module, PLL module, and SPWM module. Among them, the dq / αβ coordinate transformation module is used to convert the two-phase rotating coordinate system components into two-phase stationary coordinate system components for obtaining reference current; the abc / αβ coordinate transformation module is used to convert the three-pha...

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Abstract

The present invention relates to a three-phase grid-connected inverter grid-connected current control method, and relates to a three-phase LCL-type grid-connected inverter grid-connected current control method based on an improved repetitive controller, especially to a grid-connected inverter current control method based on an improved repetitive controller. The voltage of a direct current side ofthe inverter is controlled by a voltage regulation outer ring, the output of a direct current IP regulator is taken as a given electric current as shown in the description of a d axis in a two-phaserotating coordinate system; currents as shown in the description are subjected to inverse park transformation to obtain current set values i[Alpha]ref and i[Beta]ref in an [Alpha][Beta] coordinate system; an inner film structure with repetitive control is improved to shorten the delay time to half of the original delay time; the improvement of the repetitive control is that a proportional controller and a repetition controller are connected in parallel to improve the dynamic response capacity of the repetitive control; and a voltage of a power grid is subjected to clark transformation and thenis output after processing through a feed-forward function as output of a feed-forward link of the voltage of the power grid. The grid-connected inverter current control method based on the improvedrepetitive controller shortens the inherent delay time of the repetitive control to achieve rapid and accurate tracking of the set reference current by employing the inverter grid-connected current soas to have better steady accuracy, response speed and robustness.

Description

technical field [0001] The invention relates to a method for controlling a grid-connected current of a three-phase grid-connected inverter, in particular to a method for controlling the current of a grid-connected inverter based on an improved repetitive controller. Background technique [0002] Grid-connected inverter, as the interface device of distributed power generation system connected to the grid, plays an important role in the process of new energy grid-connected power generation. An important evaluation of the power quality of distributed power systems is the total harmonic distortion of the grid-connected current. According to the IEC61727-2004 proposed by the International Electrotechnical Commission and the national grid-connected requirements for photovoltaic systems, the total harmonic distortion of the current output by the inverter cannot More than 5%. [0003] Grid-connected inverter current control technology is one of the key technologies of the inverter....

Claims

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Application Information

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IPC IPC(8): H02J3/38H02J3/01H02M7/5387
CPCH02J3/383H02J3/01H02M7/53871Y02E10/56Y02E40/40
Inventor 王海洋王大志周迎宾于佳卉
Owner NORTHEASTERN UNIV
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