Improved control strategy for shaft system concussion inhibition of doubly-fed wind generators

A wind turbine and control strategy technology, applied in electrical digital data processing, special data processing applications, instruments, etc., can solve problems such as chipping, broken teeth, scratches on the contact surface of gears and bearings, and achieve enhanced attenuation characteristics, Increase the damping effect and increase the damping effect

Inactive Publication Date: 2018-01-30
郭琳
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  • Abstract
  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

Repeated tightening and loosening of the transmission shaft may cause scratches, cracks, chipping, or even broken teeth and broken shafts on the contact surface of the gears and bearings, resulting in long-term downtime accidents

Method used

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  • Improved control strategy for shaft system concussion inhibition of doubly-fed wind generators
  • Improved control strategy for shaft system concussion inhibition of doubly-fed wind generators
  • Improved control strategy for shaft system concussion inhibition of doubly-fed wind generators

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Embodiment Construction

[0018] specific implementation plan

[0019] figure 1 In the above, the magnetic saturation phenomenon is ignored, and the stator and rotor sides are both in accordance with the motor convention. Under the two-phase synchronous rotating coordinate system, the stator flux linkage and the rotor current are used as the state variables to establish a mathematical model of the doubly-fed generator, and the rotor voltage is obtained according to the model:

[0020]

[0021] In the formula: E dq is the back electromotive force on the rotor side; jω sl L' r i rdq is the coupling term between the d-axis and q-axis rotor current loops. The current loop of doubly-fed motor usually adopts PI regulator, after the coupling item is compensated at the output end of the regulator, the decoupling between d-axis and q-axis rotor current loop can be realized.

[0022] According to the above formula, the control structure of the q-axis rotor current loop can be obtained.

[0023] figure...

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Abstract

The invention discloses an improved control strategy for shaft system concussion inhibition of doubly-fed wind generators. The strategy comprises the following steps of: firstly calculating a theoretical expression of an electromagnetic torque under the sudden rise of power grid voltage on the basis of a doubly-fed wind generator mathematic model with a mechanical transmission system, and analyzing a mechanism of causing torsional vibration of a shaft system by high-voltage faults by combining mathematic models of two quality blocks of the shaft system; and proposing a control strategy for compensating a compensation torque which is directly proportional with a torque differential in the electromagnetic torque so as to increase model damping of the two quality blocks. According to the strategy, feature values of speed ring small-signal models are solved, stability and a free attenuation characteristic of systems after increasing compensation torques are analyzed, and a torque observeris imported to extract to-be-overlapped compensation torques.

Description

Technical field [0001] The invention relates to a doubly-fed wind power generator control strategy, in particular to an improved control strategy for doubly-fed wind power generator shaft vibration suppression. Background technique [0002] Wind turbines based on doubly fed induction generators (DFIG) are currently the most widely used wind turbines, and they are also sensitive to grid faults. The stator is directly connected to the external power grid, and the rotor is connected to the power grid through a converter. The capacity of the converter is about 20% to 30% of the capacity of the unit. When a voltage surge fault occurs in the external power grid, the machine terminal voltage will cause a series of transient processes such as rotor inrush current, DC bus overvoltage and torque oscillation. At present, the high-voltage ride-through standard for wind turbines mainly focuses on the influence of the grid voltage surge on the electromagnetic transient process of the dou...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50
Inventor 郭琳
Owner 郭琳
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