双馈感应电机稳态无功出力范围的优化算法

Optimization model for steady-state reactive output of doubly-fed induction generators

随着风电容量的增加,风电机组无功出力对风电系统电压水平和无功平衡的影响更加显著。研究了双馈感应电机(DFIG)稳态无功出力范围和最小有功损耗问题。基于感应电机扩展潮流模型,将风电机组节点功率平衡、转矩平衡和背靠背变流器稳态控制目标作为等式约束,将绕组和变流器电流和容量约束、滑差约束作为不等式约束,以无功出力最大/最小为目标,确定不同机端电压和网侧变流器无功支持下DFIG无功出力范围;以有功损耗最小为目标,确定风电机组内部无功最优分布。算例分析验证了机端电压、变流器容量及其控制目标对DFIG稳态无功特性的影响。

With increasing wind power capacity, reactive output of wind power units has more notable impact on the voltage level and vat balance of the wind power systems. In this paper, the reactive power limit and the minimum loss of the doubly-fed induction generators （DFIGs） are investigated. Based on the extended load flow model for the induction generators, the bus power balance, the torque balance, and control object of the back-to-back （B2B） converters are set as equalities, and the current and capacity limits of the stator and rotor windings and converters and the slip limit are taken as inequalities. The capacitive or inductive vat limit is quantified under different stator voltages and var outputs of the grid-side converter. The optimal var distribution inside the DFIGs is given by active loss minimization. The numerical results validate the contribution of stator voltage, converter capacity and control object to the steady-state reactive power characteristic of the DFIGs.