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A double-loop control method for a single-phase lcl type grid-connected inverter

A double-loop control and inverter technology, which is applied in the direction of single-network parallel feeding arrangement, AC network circuit, circuit device, etc., can solve the problems that the parameters of PR controller are difficult to adjust, and the influence of external interference system performance cannot be adaptively adjusted. , to achieve the effect of improving system stability, good tracking effect and improving control precision

Active Publication Date: 2020-09-01
SHANGHAI UNIVERSITY OF ELECTRIC POWER
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AI Technical Summary

Problems solved by technology

The PR link is used to eliminate the phase error, but the parameters of the PR controller are difficult to adjust, and the influence of external disturbances on system performance cannot be adaptively adjusted

Method used

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  • A double-loop control method for a single-phase lcl type grid-connected inverter
  • A double-loop control method for a single-phase lcl type grid-connected inverter
  • A double-loop control method for a single-phase lcl type grid-connected inverter

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Embodiment Construction

[0043] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is carried out on the premise of the technical solution of the present invention, and detailed implementation and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

[0044] The single-phase LCL type grid-connected inverter system is shown in 1, including the DC input voltage source U connected in sequence dc, Single-phase inverter (including switching tubes Q1-Q4) based on high-frequency switching pulse width modulation control, LCL filter (including the inductor L connected to the inverter bridge side 1 , filter capacitor C and inductance L connected to the grid 2 ), and used to detect the filter capacitor branch current i c and incoming current i grid The input detection transmitter, where Us is the grid-connected voltage, r 1 、r 2 is the e...

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Abstract

The invention relates to a double-loop control method for a single-phase LCL grid-connected inverter. The double-loop control method comprises the steps of S1, calculating the difference between a network access current measured value and a network access current reference value, and acquiring a filter capacitor current reference value through a repeated fuzzy RP controller; S2, calculating the difference between a filter capacitor current measured value and the filter capacitor current reference value, and acquiring a current control value through an inner loop proportional controller; and S3, inputting the current control value into an SPWM module, acquiring four switch driving signals, and controlling on-off of a switching device in the single-phase LCL grid-connected inverter. A proportion parameter Kc of the inner loop proportional controller is directly proportional to a damping ratio of an oscillation link. Compared with the prior art, the double-loop control method can improve the waveform quality, the tracking accuracy and the power factor of network access current under the premise of ensuring the system stability. Meanwhile, the double-loop control method is conducive to protection for a bridge arm switching tube, and ensures safe and reliable running of the whole inverter system.

Description

technical field [0001] The invention relates to the field of inverter control, in particular to a double-loop control method for a single-phase LCL type grid-connected inverter. Background technique [0002] With the development of economy and energy consumption in modern society, the pollution caused by traditional fossil energy and its own depletion are inevitable. Human beings pay more attention to renewable energy. Wind energy and solar energy are clean and non-polluting new energy sources with rich content and are the first choice. The inverter technology is one of the extremely important technologies in the process of connecting new energy to the grid. [0003] The inverter is a key device for microgrid grid-connection, and the control technology of grid-connected inverters has gradually become the focus of microgrid grid-connection. The control of grid-connected inverters can be roughly divided into three categories according to the control objects: current control,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/38
CPCH02J3/38H02J2203/20
Inventor 杨旭红王创典
Owner SHANGHAI UNIVERSITY OF ELECTRIC POWER
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