Control method of permanent magnetism direct drive wind generator system under harmonic wave power grid voltage

Abstract

The invention discloses a control method of a permanent magnetism direct drive wind generator system under a harmonic wave power grid voltage; the control method relates to the control of a grid sideconverter and a machine side converter of the permanent magnetism direct drive wind generator system; the control object of the grid side converter is set to inhibit the system total output of activeand reactive power 6-frequency multiplication pulsation component; the machine side converter employs a vector control strategy, and sends a permanent magnetism direct drive wind generator system stator average active power order, and a difference between the stator average reactive power and a corresponding feedback quantity to a machine side converter current reference value calculating module,thus obtaining a current reference value; rotor field orientation is employed to send the obtained machine side converter current reference value to a machine side converter current inner ring controllink, thus obtaining a machine side converter control voltage component. The control method can improve the output electric energy quality of the permanent magnetism direct drive wind generator system, thus reducing the DC bus voltage fluctuations, improving the service life, and reducing the operation cost.

Description

technical field [0001] The invention relates to a control method for a permanent magnet direct drive wind power generation system under harmonic grid voltage, in order to reduce the harm of the harmonic grid voltage to the permanent magnet direct drive wind power system, and improve its output power quality and grid connection stability, which belongs to the new field of energy generation. Background technique [0002] In recent years, wind energy, as a green energy, has developed rapidly in the field of renewable energy. With the increasing proportion of wind power installed capacity, the impact of wind power quality on the grid has attracted more and more attention. The permanent magnet direct drive wind power system has become one of the mainstream models of wind power generation systems due to the omission of components such as brushes, slip rings, and gearboxes, and the use of full-power converters, which have high power generation efficiency and operational reliability...

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Problems solved by technology

[0006] Literature (2) based on the analysis of the operation behavior of the permanent magnet direct drive wind power system under the unbalanced grid voltage and harmonic distortion, proposed an improved control strategy based on the resonant sliding mode controller, which improved the traditional positive and negative control strategies to a certain extent. The delay phenomenon caused by sequence current separation reduces the design difficulty of the proportional integral controller, and effectively realizes the output current balance of the permanent magnet direct drive wind power system without distortion, but the fluctuation of the total output power and the DC bus voltage is not suppressed , affecting the output power quality of the permanent magnet direct drive wind farm and the service life of the DC link capacitor

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