Multi-objective model predictive control method for doubly-fed wind turbines

Abstract

The invention discloses a multi-target model predictive control method of a double-feed wind generating set. The multi-target model predictive control method comprises the steps: 1, the stator voltageand a rotor current are sampled, discreted, and subjected positive and negative sequence decomposition; 2, positive and negative sequence components of the stator voltage and the rotor current are predicted in two steps through a predictive equation; 3, the result is calculated according to a proposed error function equation, and suitable switching vector sa (k), sb (k) and sc (k) are selected through finite control set model predictive control (FCS-MPC); and 4, alternative switching vectors for the next moment are determined according to an optimized voltage vector selection method. The capability of stable operation of the double-feed wind generating set under an unbalanced fault can be enhanced, meanwhile, complex coordinate transformation and rotor current instruction value calculation are avoided, and unified control over the rotor current of the double-feed wind generating set is achieved.

Description

technical field [0001] The invention focuses on the technical field of new energy power generation and studies the control method of the doubly-fed wind power generating set, relates to a control strategy of the doubly-fed wind power generating set under unbalanced grid voltage, and in particular relates to a multi-objective model predictive control method. Background technique [0002] With the continuous development of wind power generation technology, wind energy has become one of the most promising renewable energy sources for large-scale application. Among them, the wind power generation system based on double-fed induction generator has the advantages of variable speed constant frequency and four-quadrant operation capability, independent adjustment of active and reactive power, small converter capacity, etc., and has been widely used in the field of wind power generation. However, because the stator of the DFIG is directly connected to the grid, it is easily affected ...

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Problems solved by technology

[0004] 1) The designed control strategy requires positive and negative sequence decomposition and coordinate transformation of unbalanced voltage and current, which requires a large amount of calculation and high precision requirements;

[0005] 2) Closed-loop control of the proportional-integral regulator of the current loop in the synchronous rotating coordinate system can only achieve one control target

[0007] 1) In the reference command of closed-loop control, each current command value can only correspond to a unique control target, and the flexibility is poor;

[0008] 2) The command value calculation rules in the suppression strategy are complex and limited in actual operation control

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