基于灵敏度分析的双馈电机短路电流简化计算

Simplified Calculation of Short-Circuit Current for Doubly Fed Induction Generator Based on Sensitivity Analysis

双馈风力发电机(DFIG)在低电压穿越(LVRT)过程中,常常会在转子侧投入Crowbar电阻。Crowbar电阻的投入会对双馈风力发电机的暂态过程产生重要影响,因此双馈风力发电机的短路电流计算应计及Crowbar电阻值。推导了计及Crowbar电阻的三相短路电流计算模型,并通过仿真验证了该模型的准确性。考虑到该模型是一个包含多个参数的复杂非线性模型,在对电机各参数灵敏度分析的基础上利用多元线性回归,推导了短路电流最大值的简化计算公式。仿真分析表明,该公式的误差在工程可接受的范围内,研究结果为双馈风力发电机三相短路电流最大值的计算提供简单实用的方法。

The Crowbar resistance is often put into the rotor side to ensure the safe operation of the double fed induction generator （DFIG） in the process of low voltage ride through （LVRT）. The existence of the Crowbar resistance, however, has important influence on the transient process of DFIG, so it should be considered in the calculation of the short circuit current. In this paper, a three-phase short-circuit current calculation model with Crowbar resistance is deduced, and the accuracy of the proposed model is verified. Considering the multi-parameter and complex nonlinear characteristic of this model, this paper analyzes the sensitivity of these parameters. And on this basis, the simplified formula of the maximum short-circuit current is given by multiple linear regression. The simulation suggests that the error of the formula is within the acceptable scope of the project and the study results provide a simple and practical method for the maximum value of three-phase short-circuit current of DFIG.