A Stator Harmonic Current Suppression Method Based on Backstepping Control for Doubly-fed Asynchronous Wind Turbine Under Distorted Grid

A wind turbine and reverse thrust control technology, which is applied to control generators, control generators, control systems, etc. through magnetic field changes, and can solve the problem that the switching frequency of the converter is not fixed, the number of current harmonics is not fixed, and the reactive power fluctuates. Larger and other problems, to achieve the effect of excellent stator harmonic current output suppression effect, less adjustment parameters, and easy engineering implementation.

CN104967379BActive Publication Date: 2017-08-08ZHEJIANG UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2017-08-08

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Abstract

The invention discloses a stator harmonic current suppression method based on reverse push control of a doubly-fed asynchronous wind power generator under a distorted power grid. Under the unified mathematical model of machine ideal and harmonic grid voltage, the reverse push control algorithm is designed, and the decoupling control of active and reactive power is realized. The invention overcomes the disadvantages of poor dynamic performance of traditional vector control, and at the same time, due to the difficulty of engineering realization due to complex coordinate transformation and strict magnetic field orientation, it also overcomes the defect of poor steady-state performance of direct power control of traditional look-up table method, and can be used in ideal power grids. Excellent dynamic and static performance under the conditions.
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Description

technical field

[0001] The invention belongs to the technical field of wind power generator control, and in particular relates to a stator harmonic current suppression method based on backstepping control of a doubly-fed asynchronous wind power generator under a distorted power grid. Background technique

[0002] In the doubly-fed asynchronous wind generator (DFIG) system, the generator stator is directly connected to the power grid through a transformer, and the disturbance in the power grid will directly affect the operation of the generator itself. In addition, the capacity of the excitation converter connected to the rotor is limited, and it can only control the generator with limited capacity. Compared with the wind power generation system based on the full power converter, the doubly-fed asynchronous wind power system is very sensitive to grid faults. The ability to bear is also poor. At the same time, with more and more nonlinear loads and single-phase loads, the num...

Examples

Embodiment Construction

[0043] In order to describe the present invention more specifically, the technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0044] figure 1 The system structure of the double-fed induction wind turbine is shown. According to the principle of constant amplitude transformation, the vector form voltage equation and flux equation of the mathematical model of the rotor-side converter in the stator two-phase static α-β coordinate system can be expressed as Available:

[0045]

[0046]

[0047] Then it can be deduced that:

[0048]

[0049] The derivatives of active and reactive power absorbed by the stator of the doubly-fed induction wind turbine from the grid can be expressed as:

[0050]

[0051] Substitute and derive the apparent power expression:

[0052]

[0053] Among them, u 1 =Σj(ω h -ω f )U sαβ_h Ignorable.

[0054] Decoupling to obtain the active and...