双馈异步发电机序阻抗建模简化方法

新能源发电系统的序阻抗模型广泛应用于系统的稳定性分析和谐振分析。双馈异步发电机进行序阻抗建模时可以使用电机的电压和磁链方程或等效电路。虽然等效电路使建模过程得以简化，但是其建立的模型忽略了励磁支路的影响，且没有对简化的条件进行分析，使此类建模方法的使用产生困难。因此，基于是否计及励磁支路的电机等效电路，利用谐波线性化方法建立了双馈异步发电机转子侧的序阻抗模型，在此基础上分析两种阻抗模型之间的差异并明确简化模型的使用条件。仿真结果验证了所建立序阻抗模型的准确性，分析表明当电机的励磁支路阻抗远大于定转子阻抗时，简化模型可代替准确模型。

Simplified Method of Sequence Impedance Modeling for Doubly-fed Induction Generator

The sequence impedance model of new energy generation system is widely applied to the system stability analysis and harmonic analysis. During the se-quence impedance modeling of a doubly-fed induction generator (DFIG), the voltage and flux linkage equations of the motor or the corresponding equivalent circuit can be used. Although the equivalent circuit can simplify the modeling process, the resulting model ignores the influence of excitation branch and does not take into account the simplified conditions, which causes difficulty in using this kind of modeling method. Therefore, based on the equivalent circuit of the motor with or without the excitation branch, the sequence impedance model of DFIG on the rotor side is established using the harmonic linearization method. On this basis, the differences between the two impedance models are analyzed, and the available conditions for the simplified model are clarified. Simulation results verify the accuracy of the established sequence impedance model, and the analysis shows that the simplified model can replace the accurate model when the excitation branch impedance of the motor is much larger than the stator and rotor impedance.