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LCL filter parameter design method of grid-connected inverter for improving adaptability of weak grid

A technology of filter parameters and adaptability, applied in photovoltaic power generation, electrical components, circuit devices, etc.

Active Publication Date: 2016-12-21
合肥庐阳科技创新集团有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0009] In a word, the prior art does not mention the present, and for these two problems, the prior art also rarely discusses and solves the problem

Method used

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  • LCL filter parameter design method of grid-connected inverter for improving adaptability of weak grid
  • LCL filter parameter design method of grid-connected inverter for improving adaptability of weak grid
  • LCL filter parameter design method of grid-connected inverter for improving adaptability of weak grid

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Embodiment Construction

[0050] figure 1 is the topological structure of the grid-connected inverter LCL filter in the embodiment of the present invention. It includes a DC source Udc, a DC side filter capacitor Cdc, a three-phase half-bridge inverter circuit, and an LCL filter. The DC side filter capacitor Cdc is connected in parallel to both ends of the DC source Udc, and the two power output terminals of the DC source Udc are respectively connected to The two input terminals of the three-phase full-bridge inverter circuit are connected, the three-phase output terminals of the three-phase full-bridge inverter circuit are connected with the three-phase input terminals of the LCL filter in one-to-one correspondence, and the three-phase output terminals of the LCL filter are respectively connected with the three-phase input terminals of the LCL filter. The delta side of the Dyn11 transformer is connected, the star side of the transformer is connected to the three-phase power grid Ea, Eb, Ec, Lg is the ...

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Abstract

The invention discloses an LCL filter parameter design method of a grid-connected inverter for improving adaptability of a weak grid. The method comprises the following steps of firstly, calculating delay time of the grid-connected inverter, obtaining an open-loop transfer function according to a current control loop, obtaining system resonant frequency stability domains based on stability margin according to a generalized Nyquist stability criterion to be used as a selection basis of an LCL resonant frequency and a resonant frequency of a bridge arm side inductor and a filter capacitor, and limiting the two resonant frequencies within one of the stability domains, so that the system resonant frequency is enabled not to deviate from the stability domain when the impedance of the weak grid changes in a large range, and the system stability is improved; secondly, solving an inductance value of a bridge arm side according to maximum ripple requirement of the current of the bridge arm side inductor; and finally, solving the filter capacitance and the grid side inductance according to the two resonance frequencies. By the method, a parameter design method under different current control rings and different delay sizes is considered, a complicated and repeated trial and error step is omitted, and the calculation method is simple and intuitive.

Description

technical field [0001] The invention relates to a parameter design method of an LCL filter of a grid-connected inverter, in particular to a parameter design method of an LCL filter of a grid-connected inverter that improves the adaptability of a weak grid. Background technique [0002] Distributed power generation technology based on renewable energy (such as wind energy, solar energy, etc.) is one of the important means for human beings to deal with energy crisis and environmental pollution, and has been paid more and more attention in recent years. As the interface between the renewable energy generation unit and the grid, the grid-connected inverter plays an important role in converting the electric energy generated by the renewable energy into AC form and transmitting it to the grid. In order to transmit active power to the grid, grid-connected inverter control requires the grid voltage as a reference vector to generate a current command value, and generate corresponding...

Claims

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Application Information

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IPC IPC(8): H02M1/12H02J3/38
CPCH02J3/382H02M1/12Y02E10/56
Inventor 刘芳张杰张兴夏军徐海珍赵文广
Owner 合肥庐阳科技创新集团有限公司
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