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Method for controlling current instructions during fault ride-through period of doubly-fed fan in weak grid environment

A current command, double-fed fan technology, applied in wind power generation, single grid parallel feeding arrangement, etc., can solve problems such as the complexity of the transfer function derivation process

Active Publication Date: 2020-02-28
CHINA UNIV OF PETROLEUM (EAST CHINA)
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the derivation process of the transfer function of the system is relatively complicated, and only the transfer relationship of single input and single output can be obtained, and it is impossible to analyze the influence of each link in the system on the stability of the system one by one.

Method used

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  • Method for controlling current instructions during fault ride-through period of doubly-fed fan in weak grid environment
  • Method for controlling current instructions during fault ride-through period of doubly-fed fan in weak grid environment
  • Method for controlling current instructions during fault ride-through period of doubly-fed fan in weak grid environment

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Embodiment Construction

[0047] The present invention will be further described below in conjunction with accompanying drawings and examples of implementation.

[0048] figure 1 It is a structural schematic diagram of a doubly-fed wind turbine grid-connected system. The present invention takes a 3MW double-fed wind power generator with a rated voltage of 690V as an example, and its specific parameters per unit are as follows: stator inductance L s is 4.229p.u, the rotor inductance L r is 4.203p.u, stator and rotor mutual inductance L m is 3.99p.u, the stator resistance R s is 0.013p.u, the rotor resistance R r is 0.024p.u, filter capacitor C f is 0.15p.u, grid line resistance R eq is 0p.u, grid line inductance L eq is 0.218p.u, fault grid voltage u eq 0.4 p.u.

[0049] refer to figure 1 , a current command control method during a fault ride-through period of a doubly-fed fan in a weak network environment, the method includes the following steps:

[0050] 1. According to the requirements of ...

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Abstract

The invention discloses a method for controlling current instructions during a fault ride-through period of a doubly-fed fan in a weak grid environment. According to the method, the influence of gridconnection guideline requirements, the fan converter capacity and the system small interference stability is comprehensively considered, and active current and reactive current instructions are set. According to the invention, a small signal model of a doubly-fed wind generator grid-connected system is established, and the influence of active current and reactive current instructions on the systemstability is analyzed through the Lyapunov stability criterion, so that current instruction constraint conditions capable of enabling the system to stably operate in the grid drop fault period can beobtained. The small signal model is detailed and accurate, and the stability analysis method is simple and visual, so that a reliable reference can be provided for current instruction setting in thelow-voltage ride-through period of the doubly-fed wind power generation system in the weak grid environment.

Description

technical field [0001] The invention belongs to the field of research on grid-connected stability of doubly-fed wind power generators, and in particular relates to a current command control method during fault ride-through of doubly-fed wind power generators in a weak grid environment. Background technique [0002] With the rapid development of the wind power industry, the ratio of wind power generation to system active power is increasing all over the world, and the impact on the power grid cannot be ignored. Under such conditions, if the wind turbines are allowed to simply disconnect from the grid when the grid fails, it may cause a serious imbalance in the active power of the faulty grid, and even endanger the safety and stability of the entire system. Furthermore, since large centralized wind farms are often located in remote areas, the long transmission lines required to connect to the grid are notably high impedance, resulting in a low short-circuit ratio (SCR) of the ...

Claims

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Application Information

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IPC IPC(8): H02J3/38
CPCY02E10/76
Inventor 徐海亮王诗楠张禹风李志聂飞刘壮壮
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)
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