Positive and negative sequence decoupling control method for low-voltage ride-through compatible with grid-connected photovoltaic inverter

A low-voltage ride-through and decoupling control technology, applied in the field of solar power generation, can solve problems such as low-voltage ride-through of photovoltaic inverters and achieve the effect of maintaining stability

Inactive Publication Date: 2015-03-18
713 RES INST OF CHINA SHIPBUILDING IND CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The technical problem to be solved in the present invention is: photovoltaic inverter low voltage ride through problem, providing a positive and negative sequence decoupling control method for photovoltaic grid-connected inverter compatible with low voltage ride through

Method used

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  • Positive and negative sequence decoupling control method for low-voltage ride-through compatible with grid-connected photovoltaic inverter
  • Positive and negative sequence decoupling control method for low-voltage ride-through compatible with grid-connected photovoltaic inverter
  • Positive and negative sequence decoupling control method for low-voltage ride-through compatible with grid-connected photovoltaic inverter

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Embodiment Construction

[0033] The grid-connected photovoltaic power generation system mentioned in the present invention includes: photovoltaic components, a three-phase photovoltaic grid-connected inverter and a power grid. Three-phase grid-connected photovoltaic power generation system is the main form of large-scale photovoltaic power generation system, with complex structure, large power, high technical requirements and high efficiency. It generally uses a three-phase full bridge inverter. Photovoltaic modules are usually formed by connecting solar cells in series.

[0034] The low voltage ride-through mentioned in the present invention refers to: when the power grid has a voltage drop fault, the power generation system has the ability to continuously supply power to the power grid in a short time. The voltage drop failure mentioned in the national standard includes three-phase balance drop, single-phase drop and two-phase drop.

[0035] Such as figure 1 As shown, a photovoltaic grid-connected inve...

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Abstract

A positive and negative sequence decoupling control method for low-voltage ride-through compatible with a grid-connected photovoltaic inverter comprises the following steps: (1) a detected grid voltage is decomposed into a positive sequence component and a negative sequence component by a positive and negative sequence decoupling method, the output current of the inverter is also decomposed into a positive sequence component and a negative sequence component, and the components are controlled; and (2) the positive sequence component of the output current of the inverter is made to track the positive sequence component of the grid voltage, and the negative sequence component of the output current of the inverter is controlled to be zero so as to enable the inverter to correctly calculate the phase of the grid voltage in real time according to the drop of the grid voltage to realize phase control of the output current. The true phase of the grid voltage during low-voltage ride-through is detected by the positive and negative sequence decoupling method. Moreover, the positive sequence component and the negative sequence component of the current are controlled, and the power factor output by the inverter during low-voltage ride-through is precisely controlled. The same active current as normal operation can be output at low voltage, the output power remains unchanged, and the stability of the grid is maintained to the maximum.

Description

Technical field [0001] The invention belongs to the field of solar power generation, and specifically relates to an inverter output current control method. Background technique [0002] With the implementation of the national new energy power generation strategy, the development and utilization of solar power, a clean energy, has a broad prospect. Currently, photovoltaic grid-connected power generation systems and large photovoltaic power stations have been established. Solar panels generate electricity when exposed to sunlight, and the output is direct current, which cannot be integrated into the grid for operation. Therefore, an inverter is required to convert direct current into power frequency alternating current. According to national standards, photovoltaic grid-connected inverters need to have low voltage ride through capability. Low voltage ride through includes three situations: 1. Three-phase balanced drop; 2. Single-phase drop; 3. Two-phase drop. National standards ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38
CPCH02J3/383Y02E10/56
Inventor 王笑非谢战洪王旺球李满马新科张蕾王大鹏李莎莎
Owner 713 RES INST OF CHINA SHIPBUILDING IND CORP
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