双馈发电机定子PQ输出数值区间研究

Numerical area of DFIG stator PQ outputs

为实现双馈发电机定子侧有功、无功功率调节时确保转子变流器处于安全工作区,并实现最大限度的风能利用,通过双馈电机等效电路中电压与电流方程的建立,推导得出转子励磁电流有效值与定子侧有功、无功功率输出数值区间的映射关系,通过旋转坐标系中电压方程与磁链方程的建立及推导对上述映射关系进行验证。并提出了一种基于该映射关系的优化无功输出控制方法。仿真结果表明:在维持转子励磁电流有效值恒定的条件下,通过无功功率负方向调节可以实现发电机定子侧有功功率的正方向调节;在维持发电机定子侧有功功率输出恒定的条件下,通过无功功率负方向调节可以实现转子励磁电流有效值的负方向调节。在转子励磁变流器安全工作区内,可通过有功、无功工作点位移提高双馈发电系统极限条件下的稳定性和对原动机机械能最大限度的电能转换。

To ensure the rotor converter working in safe operating area during stator active and reactive power regulation of DFIG（Double Fed Induction Generator） and to realize the maximum utilization of wind energy, the voltage and current equations of DFIG equivalent circuit is established and the numerical area mapping relation between rotor excitation current and stator active or reactive output is deduced, which is further validated by the voltage and flux equations in rotating coordinates. An optimized reactive power control strategy is presented based on the mapping relation. Simulation results indicate that, the stator active power output increases while the reactive power decreases and the rotor excitation current keeps constant; the rotor excitation current decreases while the stator reactive power decreases and the stator active power output keeps constant. Within the safe operating area of rotor inverter, the appropriate move of active and reactive working points improves the stability and energy conversion efficiency under extreme conditions of DFIG.