Control method of doubly-fed wind power generation system under harmonic grid voltage

Abstract

The invention discloses a control method of a double-feed wind generator system under a harmonic wave power grid voltage; the method relates to the control of a machine side converter and a grid sideconverter of the double-feed wind generator system; the control object of the double-feed wind generator system machine side converter is set to inhibit a stator end to output reactive power and electromagnetic power 6 frequency multiplication pulsations; the control object of the double-feed wind generator system grid side controller is set to inhibit the double-feed system total output of activeand reactive power 6 frequency multiplication pulsations. The method can realize non-fluctuation control objects of the stator reactive power, electromagnetic torque, total output active power, and total output reactive power of the double-feed wind generator system under the harmonic wave power grid voltage, thus ensuring generators to safely and stably operate, improving the service life thereof, improving the double-feed wind generator system grid connected point electric energy quality, and improving the grid connected stability of the double-feed wind generator system under the harmonicwave power grid voltage.

Description

technical field [0001] The invention relates to a control method for a doubly-fed wind power generation system under harmonic grid voltage, in order to reduce the harm of harmonic grid voltage to the doubly-fed wind power generation system, and improve its output power quality and grid-connected stability, belonging to the field of new energy power generation . Background technique [0002] With the increasingly serious energy and environmental problems, wind power generation technology has received extensive attention and rapid development. Among them, double-fed wind turbines have become one of the mainstream models of wind power generation systems due to their advantages such as variable speed and constant frequency operation and small converter capacity. one. However, the stator windings of doubly-fed wind power systems are directly connected to the grid, which makes them extremely sensitive to changes in terminal voltage. In the actual power grid, due to the applicati...

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Problems solved by technology

Under the harmonic grid voltage, the AC side voltage and current of the grid-side converter of the doubly-fed wind power system will contain harmonic components, which will not only affect the operating efficiency of the entire system, but will further cause pulsation of the output power of the grid-side converter, thereby reducing The power quality of the power grid at the grid-connected end of the entire system

At the same time, the harmonic voltage on the AC side of the grid-side converter will also cause the pulsation of the DC-side bus voltage, which will affect the service life of the DC-side capacitor and directly affect the normal operation of the machine-side converter.

[0006] Literature (2) proposes four enhanced control objectives for the rotor-side converter of the doubly-fed wind power system in view of the harmonic grid voltage conditions, that is, to eliminate the current harmonic components at the stator end or rotor end of the generator or to eliminate the output power ripple at the stator end of the generator or to generate electricity. The reactive power and electromagnetic torque ripple at the stator end of the generator, but due to the limitation of the control variables of the rotor-side converter, the proposed control strategy cannot simultaneously achieve the four optimal control objectives under the harmonic grid voltage, and the literature does not further study the harmonic Control strategy and control objective of grid-side converter of doubly-fed wind power system under wave grid voltage

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