Optimal predictive direct power control method of doubly fed induction generator

Abstract

The invention discloses an optimal predicative direct power control method of a doubly fed induction generator. The method includes the steps that two effective voltage vectors and one zero vector are applied in each control period, one voltage vector is selected to obtain a switching list according to the predicted change conditions of active power and reactive power and the stator flux linkage positions when different control behaviors are applied, and the action time of the selected voltage vector is calculated according to the power tolerance minimum principle in the control periods; when the action time of the voltage vector obtained through calculation is negative, the voltage vectors are reselected to calculate the action time. Therefore, accuracy and effectiveness of the selected voltage vectors and the action time are guaranteed, and the active power and the reactive power of a doubly fed power generating system are independently and effectively controlled. By the adoption of the optimal predicative direct power control method, low-order current harmonics can be reduced, constant switching frequency is achieved without converting rotational coordinates and modulating the space vector pulse width, and rapid dynamic response and good steady-state performance are possessed.

Description

Technical field [0001] The invention relates to a PWM control method for a voltage converter on the rotor side of a doubly-fed asynchronous wind power generator in the field of wind power generation, in particular to a predictive direct power control method for a doubly-fed asynchronous wind power generation system. Background technique [0002] Modern large-scale wind power generation systems mainly use double-fed asynchronous generators (DFIG) and permanent magnet synchronous generators. In order to improve power generation efficiency, variable-speed and constant-frequency power generation operation methods are adopted. Among them, DFIG has the most applications and the most mature technology, and is the current mainstream model. The doubly-fed wind power generation scheme can realize variable-speed constant-frequency control, reduce the capacity of the converter, and realize the decoupling control of active and reactive power. It can output corresponding inductive or capacitiv...

AI Technical Summary

Problems solved by technology

However, the difficulty of P-DPC lies in the selection of the effective voltage vector and the determination of the effective time of each effective vector, and the possible situation that the voltage vector action time is negative will bring adverse effects on the control

The above control methods have some defects in the dynamic response of the system or in the steady-state operation, and cannot achieve the desired effect at the same time. Therefore, the in-depth research on the P-DPC implementation method of the doubly-fed induction generator has important practical significance

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