基于转子动能的DFIG频率控制策略研究

Frequency Control Strategy of DFIG Based on Rotational Kinetic Energy

变速恒频双馈风电机(doubly fed induction generation,DFIG)通过电力电子设备接入电网,所以它的有功功率输出与电网频率解耦,而且它的最大风能追踪策略使其缺乏备用,这导致DFIG对电力系统的频率调节几乎没用贡献。因此,在DFIG传统控制策略的基础上,通过研究DFIG转子动能与电力系统频率变化关系,提出转子动能控制策略。在最大风能跟踪基础上增加频率控制环节,使得电网频率变化时DFIG可迅速释放出"隐藏"的转子动能,从而为电力系统的频率变化提供支持。

A doubly fed induction generation （DFIG） naturally does not provide frequency regulation support for power system, as the electronic convertor which it used to connect with grid decouples its active power output and the grid frequency, what＇s more, the maximum power point tracking strategy makes the wind turbine generator lack power reserve. Therefore, based on the conventional control strategy of DFIG and through studying the relationship between the rotational kinetic energy of DFIG and the frequency changes of power system, a frequency control strategy based on rotational kinetic energy is presented. Frequency controlling is added on the basis of maximum power point tracking operation, which makes DFIG can rapidly release the ＂hidden＂ rotational kinetic energy when grid frequency changes, and as a result, the DFIG can provide support for the frequency changes of the power system.