Method for designing crowbar resistor for passing through low voltage of double-fed type wind generator system

Abstract

The invention relates to a method for designing a crowbar resistor for passing through the low voltage of a double-fed type wind generator system, belonging to the technical field of wind power generation and comprising the following steps: firstly, acquiring the rotor turns ratio, the rotor resistance, the rotor rated current and the rotor current upper limit of a double-fed generator of the wind generator system; computing current overload multiples according to the rotor rated current and the rotor current upper limit; acquiring the DC bus voltage of the wind generator system; computing a per-unit parameter kc of the crowbar resistor according to the DC bus voltage, the current overload multiples, the rotor rated current and the rotor resistance; obtaining a modified per-unit parameter kc after properly increasing the per-unit parameter kc; and finally, designing the resistance value of the crowbar resistor to be Rc=kcRr. The method designs the crowbar resistor according to a principle of the LVRT process of a DFIG system, adopts the clamping effect of a DC bus in the LVRT process, ensures the LVRT property while having less current and ensures the safety of a fly-wheel diode of a rotor current transformer.

Description

technical field The invention relates to a crowbar resistance design method for low-voltage ride-through of a doubly-fed wind power generation system, belonging to the technical field of wind power generation. Background technique For a grid-connected wind power generation system using a doubly-fed generator (hereinafter referred to as DFIG), when the grid voltage drops due to a short-circuit fault, it will cause a DC component in the flux linkage of the generator stator and rotor, and then induce a relatively high voltage on the generator rotor side. Large induced electromotive force. When the induced electromotive force on the rotor side exceeds the voltage control capability of the rotor-side converter, a large short-circuit current will appear on the rotor side, which may cause damage to the rotor-side converter and generator in severe cases. Therefore, during a grid short circuit, the wind power generation system will take some necessary protection measures to ensure i...

AI Technical Summary

Problems solved by technology

Due to the neglect of the important influence of the DC bus clamping effect on the short-circuit current in the LVRT process, the design of the crowbar circuit cannot achieve the expected effect; some empirical results

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