基于限功率运行的DFIG与SVG协调电压控制策略

双馈感应电机(doubly-fed induction generator,DFIG)具有变速恒频的运行特点,已成为目前的主流发电机。双馈风机能够发出和吸收无功,对风机并网点(point of common coupling, PCC)电压起到支撑作用。在分析DFIG等效电路基础上,根据DFIG定子侧输出的有功与无功关系,提出一种限功率运行条件下DFIG与静止无功发生器(static var generator,SVG)的电压协调控制策略。正常情况下DFIG工作在最大功率点跟踪(maximum power point tracking,MPPT)模式,SVG控制PCC电压在合理范围内;PCC电压越限时,DFIG进入限功率运行模式,DFIG与SVG协调控制PCC电压且优先考虑DFIG的无功调压能力。最后,基于DFIG并网的仿真模型,验证了所提出的电压协调控制策略的有效性和可行性。

Voltage Control Strategy of DFIG Coordinating with SVG Under Power-Limited Operation

Due to its variable-speed constant-frequency operation characteristics, DFIG has become the current mainstream wind power generators. DFIG can generate and absorb reactive power, and support the voltage of point of common coupling (PCC). On the basis of the analysis of the equivalent circuit of DFIG, according to the relationship between the active and reactive power output from the stator side of DFIG, a coordinated voltage control strategy of DFIG under power-limited operation and SVG is proposed. Under normal condition, DFIG operates in Maximum Power Point Tracking (MPPT) mode, and SVG controls the voltage of PCC within a reasonable range. When the voltage of PCC exceeds the limit, DFIG enters the power-limited operation mode. Then DFIG and SVG coordinately control the voltage of PCC and the reactive power regulation capability of DFIG is in priority use. Finally, the effectiveness of the proposed voltage coordinated control strategy is verified by simulation.