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High-frequency resonance suppression method for LCL grid-connected inverter connected to high-order distribution network

A high-frequency resonance, inverter technology, applied in AC networks to reduce harmonics/ripples, harmonic reduction devices, etc., can solve problems affecting system stability, system stability effects, complex high-order characteristics, etc. Achieve the effect of reducing harmonic content, suppressing high-frequency resonance phenomenon, and improving dynamic stability

Inactive Publication Date: 2019-02-26
STATE GRID JIANGSU ELECTRIC POWER CO LTD NANTONG POWER SUPPLY BRANCH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The LCL filter itself is a third-order undamped system, and its parameters will affect the stability of the system.
[0003] In addition, with the continuous deepening of urbanization, the increase of cable laying rate in the distribution network system, the increase in the investment of system capacitive reactive power compensation devices, etc., the grid impedance of the distribution network system can no longer be simply equivalent to a set overall inductance parameters, but exhibit complex higher-order characteristics
After the LCL type grid-connected inverter is connected to the high-order distribution network system, high-frequency resonance will occur with the distribution network system, which will affect the stability of the system

Method used

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  • High-frequency resonance suppression method for LCL grid-connected inverter connected to high-order distribution network
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  • High-frequency resonance suppression method for LCL grid-connected inverter connected to high-order distribution network

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Embodiment Construction

[0023] The present invention will be further described now in conjunction with accompanying drawing. These drawings are simplified schematic diagrams only to illustrate the basic structure of the present invention in a schematic way, so they only show the components relevant to the present invention.

[0024] A high-frequency resonance suppression method for connecting an LCL grid-connected inverter to a high-order distribution network, including an LCL grid-connected inverter and a control circuit, the LCL grid-connected inverter includes a DC voltage source connected to a DC voltage The filter capacitor at both ends of the source, the inverter connected to both ends of the DC voltage source, and the LCL filter, and the inverter is connected to the high-order distribution network through the LCL filter. The LCL grid-connected inverter is connected to the high-order distribution network to form the LCL grid-connected inverter and the high-order distribution network system.

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Abstract

The invention relates to a high-frequency resonance suppression method for an LCL grid-connected inverter connected to a high-order distribution network, comprising an LCL grid-connected inverter anda control circuit, wherein the LCL grid-connected inverter comprises a DC voltage source, a filter capacitor, an inverter, and an LCL filter; and the inverter is connected to the high-order distribution network through the LCL filter. The control method of the control circuit comprises that inflow current forms an inflow current value through an inflow current feedback coefficient Hi2; a difference between an inflow current reference instruction value and the inflow current value is used as an input of the filter module; the capacitance current obtained in the LCL filter forms a capacitance current output value through a capacitance current feedback coefficient Hi1; a difference between the output of the filter module and the capacitance current output value is used as an input of a PWM generating circuit SPWM; and the output of the PWM generating circuit SPWM is output to the inverter. The method can suppress the high-frequency resonance generated by the LCL grid-connected inverter connected to the high-order distribution network.

Description

technical field [0001] The invention relates to the technical field of grid-connected inverters, in particular to a high-frequency resonance suppression method for LCL grid-connected inverters connected to high-order distribution network systems. Background technique [0002] In the development of distributed power generation technology, with the increasing proportion of new energy power generation technologies such as photovoltaic power generation and wind power generation connected to the grid, grid-connected inverters, as the interface between distributed power generation and distribution network systems, undertake more and more more important role. Due to the modulation effect of PWM, the power switching device will generate a large number of high-frequency harmonics during the working process, so it is necessary to add a filter between the inverter and the distribution network system. Compared with the L-type filter, the LCL-type filter is widely used due to its small ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/01
CPCH02J3/01Y02E40/40
Inventor 毛艳芳刘飞胡广江陈桢冯鹏
Owner STATE GRID JIANGSU ELECTRIC POWER CO LTD NANTONG POWER SUPPLY BRANCH
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