Crowbar device for low voltage ride-through of wind generator set and control method of device

Abstract

The invention discloses a Crowbar device for low voltage ride-through of a wind generator set and a control method of the device. The device comprises an uncontrolled rectifier bridge G, a controllable component QS, a controllable component QX and a bleeder resistor RC, wherein an input end of the uncontrolled rectifier bridge G is connected with A, B and C phases on a rotor side of a double-fed asynchronous generator; the controllable component QS and the controllable component QX are connected with an output end of the uncontrolled rectifier bridge G in series; one end of the bleeder resistor RC is connected with a connection point of the controllable component QS and the controllable component QX; and the other end of the bleeder resistor RC is connected with a positive output end or a negative output end of the uncontrolled rectifier bridge G; The device is simple in structure and lower in cost, and solves the problems that the existing Crowbar is complicated in structure and higher in cost.

Description

technical field [0001] The invention relates to a Crowbar device used for low-voltage ride-through of wind turbines and a control method thereof. Background technique [0002] With the continuous increase of wind power installed capacity, wind turbine off-grid accidents occur frequently. The Electric Regulatory Commission mainly focuses on the national wind power safety of "the detection and transformation of the low voltage ride-through capability of wind farm units and the impact of wind farms on the local power grid after they are connected to the system". The inspection officially started in August 2011. In order to comply with this requirement of the new national standard, the low voltage ride-through function transformation of installed and running wind turbines and the low voltage ride through function test of new wind turbines are all put into action. The low-voltage ride-through function of wind turbines, especially double-fed wind turbines, has become the focus of...

AI Technical Summary

Problems solved by technology

For example, the patent application number 201010266619.9 proposes a low-voltage ride-through crowbar circuit. The crowbar circuit includes at least one set of main thyristors and an auxiliary circuit composed of auxiliary thyristors, capacitors and reactors. The main thyristors and auxiliary circuits realize the Crowbar circuit together. This kind of conventional active crowbar design often leads to secondary or multiple overcurrent of the converter during grid voltage recovery, and then the crowbar cannot even be switched out, resulting in the reactive power support time and recovery power required by the national standard. The time cannot be guaranteed; in order to solve this problem, the patent No. 201110267179.3 proposes a Crowbar structure. When the power grid voltage drops, according to the different degree of power grid drop, different numbers of energy consumption resistors are switched through the IGBT in the Crowbar circuit device in stages. To reduce the reactive power absorbed when the Crowbar device is put in and cut out, so as to reduce the reactive power fluctuation when the Crowbar device is put in and cut out, to realize the low voltage ride-through function of the fan; the variable resistance proposed by the patent No. 201110175899.7 Crowbar structure, through the parallel Crowbar structure algorithm of the variable resistance Crowbar structure of the corresponding structure or the chopping Crowbar structure algorithm to obtain the control signal of the Crowbar, respectively control the opening and closing of the controllable devices of the Crowbar, so as to change the size of the Crowbar resistance to realize the fan. Although the above two patents use different methods to change the size of the bleeder resistor to improve the performance of low voltage ride through, the proposed Crowbar consists of two or more IGBTs, or even more An uncontrolled rectifier bridge, the structure is relatively complex, and because of the low-voltage ride-through drop and recovery instantaneous transient current is very large, so the withstand current capability of the IGBT of the Crowbar must be relatively large, and the price is relatively expensive, so the cost is very high

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