Low-voltage ride-through control method based on photovoltaic grid-connected inverter

A low-voltage ride-through and control method technology, applied in the direction of AC network voltage adjustment, single-grid parallel feeding arrangement, reactive power compensation, etc. Large and other problems, achieve high engineering practical value, reduce positive and negative sequence separation calculation, and improve reliability.

Inactive Publication Date: 2019-11-29
NANJING UNIV OF SCI & TECH
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  • Application Information

AI Technical Summary

Problems solved by technology

[0005] When the power grid drops and fails, the inverter current increases sharply, which may damage the power switch tube due to excessive current, resulting in failure of low voltage ride through
However, the traditional photovoltaic low-voltage ride-through technology focuses more on power and current quality, and less research on over-current problems

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  • Low-voltage ride-through control method based on photovoltaic grid-connected inverter
  • Low-voltage ride-through control method based on photovoltaic grid-connected inverter
  • Low-voltage ride-through control method based on photovoltaic grid-connected inverter

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Embodiment Construction

[0018] In order to solve the above technical problems, the present invention proposes a low-voltage ride-through control method based on photovoltaic grid-connected inverters, including the following steps:

[0019] Step 1. According to the topological structure of the main circuit of the grid-connected inverter, the power model of the grid-connected inverter under the condition of grid voltage asymmetry is established, and the mathematical model of the active power and reactive power output by the grid-connected inverter is Transform from the d-q coordinate system to the α-β coordinate system to obtain the mathematical model of active power and reactive power in the α-β coordinate system;

[0020] Step 2. According to the calculated positive and negative sequence voltage amplitudes, determine the type of drop, and calculate the given value Q of positive and negative sequence reactive power according to the type of drop * , and then calculate the average active power P output ...

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Abstract

The invention discloses a low-voltage ride-through control method based on a photovoltaic grid-connected inverter. Large and medium-sized photovoltaic power supplies should have the capability of bearing a certain voltage abnormality, so as to avoid the severe impact on a power grid from the sudden off-grid of the photovoltaic power supplies. When a power grid breaks down or large disturbance occurs, the power grid is cut off to bring very severe impact to the power grid, in order to effectively avoid the impact influence on the power grid, the injected reactive power acts on the inductive impedance to generate a corresponding voltage, so that the voltage of the grid-connected point is increased, the voltage of the power grid is supported, and the safety and stability of the power system are improved.

Description

technical field [0001] The invention belongs to the field of electric power systems and automation thereof, and in particular relates to a design of a low-voltage ride-through controller based on a photovoltaic grid-connected inverter. Background technique [0002] In recent years, the proportion of photovoltaics in the power system has been increasing, which has led to the fact that when the grid fails or there is a large disturbance, cutting off the photovoltaic power supply will often bring a very serious impact on the grid. Therefore, from the perspective of safe operation of the power grid, both large and medium-sized photovoltaic power sources should have the ability to withstand a certain voltage abnormality, so as to avoid the adverse impact on the power grid caused by the sudden disconnection of photovoltaic power sources. Similar to the low-voltage ride-through technology of wind power generation, when the power grid fails or is subject to major disturbances, the v...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02J3/16
CPCH02J3/16Y02E40/30
Inventor 张晶鲁裕婷赵天乐张馨文
Owner NANJING UNIV OF SCI & TECH
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