Doubly-fed wind power converter low-voltage traversing topological structure and control method thereof

Abstract

The invention discloses a doubly-fed wind power generator low-voltage traversing converter topological structure and a control method thereof. The low-voltage traversing converter topological structure mainly consists of a triangular structure consisting of bidirectional controllable silicon, and a voltage source type back-to-back converter, and is characterized in that: the triangular structure is formed by connecting three pieces of bidirectional controllable silicon and resistors sequentially; and the three peaks of the triangular structure are connected with three alternating-current output points of a doubly-fed motor rotor side converter respectively. Aiming at the capacity requirement on the rotor side converter during low-voltage traversing of the doubly-fed wind power generator, the invention adopts that: the triangular structure consisting of the bidirectional controllable silicon is arranged in the doubly-fed motor rotor side converter; two working modes, namely active bar crowing and cooperative control, are formed due to matched control of the controllable silicon in the triangular structure and a bridge-arm switch of the doubly-fed motor rotor side converter, so thatthe processing capability to the current of a doubly-fed motor rotor; therefore, the low-voltage traversing function of the doubly-fed wind power generator is realized better due to low-cost and high-reliability converter structural variation.

Description

technical field [0001] The invention belongs to the field of wind power generation, in particular to a doubly-fed wind power generator low-voltage ride-through converter topology and a control method thereof. technical background [0002] Doubly-fed wind turbines are the mainstream type of megawatt-scale variable-speed constant-frequency wind turbines. With the increase of wind power grid penetration, the low-voltage ride-through (LVRT) function of wind turbines is a must for current wind turbines. standby function. For example, the grid code for high and extra high voltage issued by E.ON Netz in Germany in 2006, and the enterprise standard of State Grid Corporation of China (Q / GDW392-2009) all proposed the LVRT function of wind turbines. specific requirements. Due to the special drive topology of the double-fed generator in the double-fed wind turbine, it is difficult for the back-to-back drive converter to meet the current capacity requirements of the LVRT, which also ma...

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Problems solved by technology

For example, the rotor circuit additional hardware scheme of the rotor circuit series resistor or the resistance-sensing network tries to limit the rotor current and thereby suppress the crowbar action when the power grid fails, but the fast input control problem and parameter design problem of the additional hardware limit its application; the stator circuit The additional hardware scheme of the stator circuit with additional series-connected power electronic switches tries to temporarily disconnect from the grid to overcome the problems of reactive power absorption and electromagnetic torque impact when the power grid fails, but the design of fast power electronic switches and its impact on steady-state operating efficiency It also limits its application; the additional hardware scheme of the stator circuit with a series converter or an additional passive impedance network has a good LVRT potential in theory, but it requires too much additional hardware, high cost, and difficult design

Looking at these additional hardware solutions, although the shortcomings of the crowbar circuit can be overcome, the additional hardware is becoming more and more complex, and the cost impact is increasing

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