Double-fed induction generator wind turbine Crowbar resistance design method based on fuzzy membership function

Abstract

The invention discloses a double-fed induction generator wind turbine Crowbar resistance design method based on a fuzzy membership function. The double-fed induction generator wind turbine Crowbar resistance design method comprises the following steps: according to an equivalent circuit model of a double-fed induction generator wind turbine in case of a power grid fault, and with the combination of a maximum fault current limiting condition and a direct-current bus capacitor voltage limiting condition, acquiring extreme value constraint relationship equations of rotor current and the Crowbar resistance as well as the direct-current bus voltage and the Crowbar resistance; respectively establishing fuzzy membership functions of the two constraint relationship equations according to the membership degree function concept of the fuzzy control principle; confirming the cross point of the two fuzzy membership functions in one same coordinate axis, thereby obtaining the Crowbar resistance corresponding to the cross point which is taken as the Crowbar resistance confirmed by using the method. By adopting the method, both the influence of over current of a rotor current transformer and the limiting condition of over voltage of direct current procedures of the rotor current transformer are considered, so that the security operation of the rotor current transformer of the double-fed induction generator wind turbine in a fault period is ensured to a maximum extent.

Description

technical field [0001] The invention relates to the determination of Crowbar resistance in a doubly-fed wind turbine, specifically a method for designing the crowbar resistance of a doubly-fed wind turbine based on a fuzzy membership function, and belongs to the technical field of wind power generation. Background technique [0002] With the continuous growth of my country's wind power installed capacity, a series of problems brought about by wind power grid integration have become more and more prominent. Doubly-fed wind generator (DFIG) is the main type of wind power generation, accounting for more than 50% of wind power grid-connected capacity. The stator of the double-fed wind turbine is directly connected to the grid, and the rotor side is connected to the grid through the grid-side and machine-side converters. Since the capacity of the converter of the double-fed wind turbine is relatively small, when the grid voltage drops, it is necessary to pay attention to the roto...

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Problems solved by technology

[0012] In view of the shortcomings of the low-voltage ride-through crowbar protection circuit of the existing doubly-fed wind turbines, the efficiency of the pilot-scale method of resistor selection is not high and it is difficult to achieve the optimal design effect. The purpose of the present invention is to propose a doubly-fed wind turbine based on fuzzy membership function Crowbar resistor design method, this method can not only consider the impact of the rotor converter current overcurrent, but also take into account the constraints of the converter DC link overvoltage, so as to protect the DFIG converter in the fault stage to the greatest extent safe operation of

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