Doubly-fed induction wind driven generator transient current tracking control method under power grid faults

Abstract

The invention discloses a doubly-fed induction wind driven generator transient current tracking control method under power grid faults, and belongs to the technical field of wind power generation. A rotor current instruction feedforward component related with a rotor transient current instruction is attached to a current loop of a rotor side converter, so as to improve a capability of the original current loop in tracking an alternating current instruction, thereby fully excavating characteristics corresponding to the transient current instruction, and enhancing low voltage ride through capacity of the doubly-fed induction wind driven generator. The control method provided by the invention has the advantages that the structure is simple, implementation is easy, stability of the original current loop is not changed, and in addition, the method has relatively high robustness in power grid frequency fluctuation and doubly-fed induction wind driven generator parameter drift.

Description

technical field [0001] The invention belongs to the technical field of wind power generation, and more specifically relates to a transient current tracking control method of a doubly-fed induction wind power generator under a grid fault. Background technique [0002] With the increase of the penetration rate of wind power in the power grid, various countries have proposed corresponding grid-connected regulations for wind turbines; among them, the most concerned one is the low voltage ride-through requirement, that is, during the grid fault, the wind turbines can not be disconnected from the grid and operate in the grid. Provide reactive power support to the grid within the specified time. [0003] Among various wind turbines, doubly-fed wind turbines have the advantages of small converter capacity, variable frequency and constant speed, reactive power and active power decoupling control, etc., and have become the current mainstream models; however, doubly fed induction gener...

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Problems solved by technology

[0011] Literature [1] proposed a PI control scheme in the positive and negative sequence double dq coordinate system, which realized the independent adjustment and effective control of the positive and negative sequence currents of the doubly-fed induction wind turbine. However, due to the need to use filters to Separating the positive and negative sequence components of the current will introduce time delay and amplitude attenuation, which will affect the dynamic response speed and steady-state control accuracy of the control system

Literature [2] proposed a proportional resonance (Proportional-Resonant, P-R) control scheme in the static αβ coordinate system of the two-phase stator, which realized the unified adjustment of the positive and negative sequence currents of the doubly-fed induction wind turbine rotor without separation. However, , this scheme needs to make major structural changes to the traditional vector control system designed under steady-state conditions, which affects the industrial application prospect of this scheme

Literature [3] proposes a PI-R control method in a synchronous rotating coordinate system, and uses a resonant controller to achieve precise control of the AC component command. However, the phase lag of the resonant component will lead to a decline in the dynamic performance of the original system.

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