Real-time detection method for double-SRF dual-feedback aerogenerator rotor current positive and negative components

Abstract

The invention discloses a method for detecting positive and negative sequence components of rotor current of a doubly fed wind power generator under double SRF in real time, which comprises the following steps:1) continuously sampling an instantaneous value of a current three-phase rotor current signal; 2) detecting an angle synchronously rotated with an electric network in the sampling moment; 3) detecting a rotor electrical angle; 4) converting the sampled instantaneous value from a three-phase immobile coordinate system to a two-phase immobile coordinate system; 5) obtaining angles of the positive and negative sequence components of the rotor current at sampling moments through calculation according to a formula (2); 6) obtaining the positive and negative sequence components of the rotor current of the doubly fed wind power generator under the current two-phase immobile coordinate system through calculation according to a formula (3); and 7) performing inverse Clark transform on the positive and negative sequence components of the rotor current of the doubly fed wind power generator under the two-phase immobile coordinate system for calculation to obtain the positive and negative sequence components of the rotor current. The detection method has simple algorithm, no plural calculation, no filter, no need of constructing a synchronous rotating vector for voltage and current,and strong real-time; and the algorithm has no delay, and is easy to realize in engineering.

Description

technical field [0001] The invention relates to a real-time detection method for the positive and negative sequence quantities of the rotor current of a doubly-fed wind power generator under double SRF, and belongs to the technical field of electric control. Background technique [0002] Doubly-fed wind power generation technology is the mainstream technology widely used in large-scale wind turbines. When the power grid connected to the double-fed generator is unbalanced (there is a negative sequence voltage component in the grid voltage), it will cause problems such as heating of the stator winding, torque ripple of the generator, and power oscillation to the power grid; at the same time, in double-fed wind power The positive sequence and negative sequence quantities are induced in the generator rotor current. Therefore, in the rotor current control system of the doubly-fed wind turbine, it is necessary to detect the positive sequence and negative sequence of the rotor cur...

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Problems solved by technology

[0004] (1) The detection method based on low-pass filtering. The characteristics of this type of method: ① It does not need to use the voltage waveform as a reference, so it can be used to detect the harmonic component in the current; ② It depends too much on the adjustment of the filter parameters and cannot compensate The phase shift caused by the filter is susceptible to the influence of the system frequency offset; ③ cannot compensate for the delay caused by low-pass filtering;

[0005] (2) The detection method based on the notch filter. The characteristics of this type of method: ① It does not need to use the voltage waveform as a reference, so it can be used to detect the harmonic component in the current; Compensate for phase shifts caused by notch filters, susceptible to system frequency offsets;

[0006] ③ Unable to compensate for the delay caused by the notch filter

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