Inverter grid-connected system and control method thereof

An inverter and inverter technology, which is applied in the direction of single-grid parallel feeding arrangement, etc., can solve the problems of circuit current surge, protection device action, damage to switching devices, etc.

Inactive Publication Date: 2014-12-03
JIANGSU EVER SOLAR NEW ENERGY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In addition, excessive grid-connected current can easily cause inductance saturation, which will cause a sharp i...

Method used

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  • Inverter grid-connected system and control method thereof
  • Inverter grid-connected system and control method thereof
  • Inverter grid-connected system and control method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0051] Such as figure 2 As shown, it is a schematic structural diagram of a three-phase inverter grid-connected system. The system has:

[0052] DC / DC module 1; DC / AC module 2; filter unit 3; grid-connected switch 4; power grid 5; inverter current signal acquisition device 6; inverter voltage signal acquisition device 7; grid signal acquisition device 8;

[0053] The output end of the DC / DC module 1 is connected to the input end of the DC / AC module 2, the output of the DC / AC module 2 is passed through the filter unit 3, and the grid-connected switch 4 is connected to the grid 5;

[0054] The inverter current signal acquisition device 6 is arranged between the DC / AC module 2 and the filter unit 3, and is used to collect the inverter output current as a current feedback signal in the inverter control loop;

[0055] The inverter voltage signal acquisition device 7 is arranged between the filter unit 3 and the grid-connected switch 4, and is used to collect the output voltage of...

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PUM

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Abstract

The invention provides an effective method for reducing impact current of inverters in grid connection so that the inverters can switch to the grid-connected operating state from the independent operating state easily and effectively. According to the mechanism, if the voltages on the two sides of a grid connection switch have the same amplitude and phase in grid connection, voltage difference does not exist, and thus impact current cannot be generated; in independent operation, inversion voltage becomes higher and higher, impact on filter capacitors is reduced, and in grid connection, the voltages on the two sides of the grid connection switch are consistent, and generation of impact current is suppressed; after grid connection, because double-loop control is adopted and only a given current loop is switched, sudden change of current can be effectively reduced, and smooth transition is achieved.

Description

technical field [0001] The invention relates to a control method for an inverter grid-connected system, in particular to a control method for reducing the grid-connected impact current during the smooth transition of an inverter from independent operation to grid-connected operation. Background technique [0002] Distributed power generation usually refers to a power generation system that utilizes distributed resources, has a small installed capacity, and is arranged near users. It is generally connected to a power grid with a voltage level of less than 35 kV or lower. Distributed photovoltaic power generation can meet the requirements of ready-to-use, reduce power transmission and transformation costs and power loss. [0003] The inverter converts DC power and other electric energy into AC power with the same frequency and amplitude as the grid through reasonable control, which can be supplied to users off-grid or grid-connected. With the promotion of distributed power ge...

Claims

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Application Information

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IPC IPC(8): H02J3/38
Inventor 张勇程凌国姚东忏顾月明
Owner JIANGSU EVER SOLAR NEW ENERGY CO LTD
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