Low voltage ride through protection method for doubly fed induction generator

Abstract

The invention discloses a low voltage ride through protection method for a doubly fed induction generator. The method specifically includes the steps that a crowbar circuit is in parallel connection beside a direct-current side capacitor of the doubly fed induction generator, after a grid fault occurs, the crowbar circuit is started, and accordingly direct-current side voltage after breakdown is maintained stably. A voltage response quality evaluation index is applied to the magnitude of crowbar resistance, the optimal value of the crowbar resistance is determined through influences of direct-current crowbar resistance on the index so that the optimal control effect can be achieved, and the direct-current side voltage is more stable after the fault occurs and can rapidly recover. The invention further provides a scheme that a bypass capacitor is in series connection with the crowbar circuit, and recovery cycles of currents and voltage of a system after the fault occurs are effectively reduced.

Description

technical field [0001] The invention belongs to the technical field of wind power generation, and more specifically relates to a low-voltage ride-through protection method for a doubly-fed asynchronous wind power generator. Background technique [0002] With the continuous development of the economy, the demand for renewable energy has been widely concerned, and wind power generation has attracted more and more attention from all over the world because of its advantages. Among them, the double-fed asynchronous wind power generator system is currently the main form of wind power generation. . However, when the grid voltage fluctuates, the doubly-fed asynchronous wind generator (DFIG) system will appear abnormal. As the capacity of wind turbines increases, the previous method of directly disconnecting wind turbines from the grid to deal with grid voltage dips is no longer applicable. [0003] Crowbar technology (Crowbar) is an effective means to realize the survivability of ...

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Problems solved by technology

[0008] The above studies have achieved good results. At the same time, the patent CN101621204A also discloses a crowbar resistance design method for low-voltage ride-through of double-fed wind power generation systems, but the above work focuses on the impact of crowbar resistance on the system. protection limitations, and little attention has been paid to the optimization of system response by crowbar circuit resistance

At the same time, there are great limitations in system protection only relying on the crowbar circuit

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