Double-fed fan crowbar adaptive cut-out control method for preventing repeated switching of crowbar

Abstract

The invention discloses a double-fed fan crowbar adaptive cut-out control method for preventing repeated switching of a crowbar. The method comprises the following steps of: when an amplitude of a rotor current exceeds an operating value of a crowbar at the side of the rotor, placing the crowbar and simultaneously, locking a converter at the side of the rotor; if the rotor current is smaller than the operating value of the crowbar, calculating a rotor current maximum value which is to be generated when assuming that the crowbar is cut out at a current moment, and when the rotor current maximum value is smaller than the operating value of the crowbar, cutting out the crowbar and recovering working of the converter at the side of the rotor; and in a fault period, setting a q-axis component of the rotor current according to a preferred output reactive power of a double-fed wind driven generator, and enabling reference values of d-axis and q-axis components of the rotor current to meet constraint conditions. According to the double-fed fan crowbar adaptive cut-out control method disclosed by the invention, the crowbar is guaranteed to be cut out as soon as possible in the premise that the crowbar cannot be placed, so that placing time of the crowbar is shortened and effects that a slave system absorbs the reactive power a little and safety influence on a fan and a control device thereof is reduced are achieved.

Description

technical field [0001] The invention relates to the field of low-voltage ride-through of wind farms, in particular to a crowbar adaptive cutting control method for double-fed wind turbines to prevent repeated crowbar switching, and a rotor-side converter auxiliary control strategy coordinated with crowbar cutting. Background technique [0002] Doubly-fed wind generator (DFIG), as one of the current mainstream wind turbines, has the characteristics of small converter capacity, independent decoupling control of active power and reactive power, and its capacity in the grid has increased rapidly year by year. When the power grid failure causes the voltage drop at the grid-connected point, if all the wind turbines in the large-capacity wind farm are disconnected from the grid, it will have an adverse effect on the safe operation of the power system and cause power imbalance in the grid. Therefore, it is required to have a certain low voltage ride through (LVRT) capability. At pr...

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Problems solved by technology

[0005] 1. When the fault is more serious, the crowbar will switch repeatedly, which increases the reactive power of the system absorbed by DFIG, which is not conducive to the recovery of system voltage, and at the same time will reduce the service life of power electronic switching devices, and bring DFIG The impact of electromagnetic torque will cause harm to the safety of the fan;

[0006] 2. When the fault is relatively minor, the delayed removal of the crowbar makes the input time of the crowbar too long, which increases the system reactive power that DFIG needs to absorb during the crowbar input period, which is not conducive to the low voltage ride-through performance of DFIG

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