Doubly-fed wind generator rotor linkage deadbeat fault operation method

Abstract

The invention discloses a doubly-fed wind generator rotor linkage deadbeat fault operation method. When power grid voltage drops, by means of a rotor voltage prediction model, in order to make the rotor linkage follow a given value in the model to realize the deadbeat control of the rotor linkage, the value of the rotor linkage at the next moment needs to be replaced by the given value of the rotor linkage at the next moment, the given value of the rotor linkage follows the actual value of the stator linkage, the predicted rotor voltage in a two-phase synchronous rotating coordinate system is subjected to coordinate reversion to obtain the rotor voltage in a two-phase rotor rotating speed rotating coordinate system, and at the end, PWM modulation is carried out. The fault operation method has the advantages of simple operation, good decoupling, fast dynamic response, and high robustness. The rotor linkage deadbeat control method is provided under the power grid fault state, the rotor fault current can be controlled within 1.5-1.6 times of the rated current, the electromagnetic torque ripple during the failure is reduced, the dynamic response speed is fast, and the control precision is high.

Description

technical field [0001] The invention belongs to the technical field of doubly-fed wind power generator operation control, and specifically relates to a power prediction control in a steady state of a power grid and a dead-beat control method for a rotor flux linkage when a power grid suddenly drops, improving stability in normal operation and doubly-fed in a fault state Fault operation capability of wind turbines. Background technique [0002] In recent years, the electric power industry has developed rapidly in our country and attracted people's attention. With the continuous expansion of the scale of wind farms and the continuous increase of the stand-alone capacity of wind turbines, the penetration rate of wind power in the grid has gradually increased. Although the rapid development has brought considerable economic benefits, it has also caused certain damage to the stability of the power system. The large-scale disconnection of wind turbines caused by grid failure wil...

AI Technical Summary

Problems solved by technology

The first is to achieve fault operation capability by improving the excitation control strategy. This method is suitable for minor faults. In the case of a deep grid voltage drop, this excitation control algorithm is difficult to achieve fault operation control of the power generation system.

The second is the series grid-side converter. This method can realize fault operation under any circumstances, but its connection method is complicated and expensive, and it is rarely used in practical applications.

When the power grid voltage has a single-phase drop of 90% or a three-phase symmetrical drop of 70%, most of the current control methods are difficult to control the rotor current value during the fault period within 2 times of its rated current, and the electromagnetic torque fluctuation is relatively large. The impact force of the unit is great

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