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Smooth switching control method for three-phase dual-mode inverter

A control method and smooth switching technology, applied in the direction of single-network parallel feeding arrangement, etc., can solve problems such as large current impact and DC side voltage fluctuations

Active Publication Date: 2014-07-16
ZHANGZHOU KEHUA TECH CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a smooth switching control method for a three-phase dual-mode inverter to solve the problem of large current impact when the inverter is connected to the grid and the The problem of voltage fluctuation on the DC side caused by the inability to quickly shut off the current

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  • Smooth switching control method for three-phase dual-mode inverter
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  • Smooth switching control method for three-phase dual-mode inverter

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Embodiment Construction

[0044] figure 1 It is a schematic diagram of a parallel structure of a microgrid dual-mode inverter in an embodiment of the present invention, mainly including: a full-bridge inverter circuit, a filter, a local load, an on / off grid switch, a power grid, and the like. The distributed power supply is converted into a constant voltage direct current with a voltage of U dc ; DC power is converted to AC power through a three-phase PWM inverter circuit; the filter is used to filter out glitches caused by high-frequency switching, u o i o Output voltage and current for the inverter after the filter; output AC to the local load Z load Provide electric energy, on / off-grid switch S is used to connect micro-source and grid. where the voltage at the point of common connection (PCC) is u s , the grid voltage mentioned in the present invention refers to the voltage at the PCC.

[0045] figure 2 It is a smooth switching control block diagram of a dual-mode inverter according to an emb...

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Abstract

The invention discloses a smooth switching control method for a three-phase dual-mode inverter. The method comprises off-grid and grid-connected smooth switching control and off-grid smooth switching control. Smooth control comprises soft start of virtual impedance and monocycle current feedback control. When the inverter is switched to the grid-connected mode from the off-grid mode, output current phase lead control and smooth switching control are conducted, temporary impact of output currents and in-network currents of the inverter are restrained, and then backward flowing of energy of the inverter is greatly reduced, and grid-connected smooth switching is achieved. When the inverter is switched to the off-grid mode from the grid-connected mode, only monocycle current feedback control is conducted, the in-network currents are reduced to zero quickly, DC side voltage fluctuation of the inverter caused by temporary unbalance of the currents is avoided, and off-grid smooth switching is achieved. According to the method, the problems that current impact is large when the micro-grid inverter is connected to the grid and DC side voltage fluctuates when the inverter is off-grid are solved, and smooth switching of the operation modes of the micro-grid is achieved.

Description

technical field [0001] The invention relates to the field of micro-grid distributed power generation, in particular to a control method for smooth switching of dual-mode inverters in a micro-grid. Background technique [0002] Accepting and utilizing distributed power sources (photovoltaic, wind power, fuel cells, etc.) through microgrids is an effective way to solve the current energy crisis and environmental degradation. Therefore, it is of great significance to study inverters suitable for microgrid operation. Existing research mainly focuses on the control method of the inverter working alone in grid-connected mode or off-grid (island) mode, but for inverters that can work in both grid-connected and off-grid modes, and the corresponding smoothing The research on switching control is still incomplete. [0003] In a highly flexible microgrid, the inverter should have the ability to provide power to the local load and the grid at the same time, and under abnormal circumst...

Claims

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Application Information

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IPC IPC(8): H02J3/38
Inventor 陈燕东罗安王明玥周乐明黄媛陈智勇龙际根周小平匡慧敏
Owner ZHANGZHOU KEHUA TECH CO LTD
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