A Robust Frequency Estimation Method for Aircraft Grids Under Distorted Conditions

In aircraft grids, the voltage frequency is much higher than that in utility power systems and it challenges the dynamics of frequency estimations. In this letter, a fast and robust frequency estimation method is proposed for aircraft grids even when the grid voltage is distorted. In detail, a mathematical model is established based on the relationship among the fundamental grid voltage, harmonics and their time-delay signals. Accordingly, a robust parameter identification method is proposed to achieve grid frequency estimation and harmonic immunity. Compared with the frequency estimations for utility power systems, the proposed method, so-called robust frequency estimation (RFE), has faster dynamics and stronger harmonic suppression capability. Hence, it takes advantages in the applications of aircraft grids. Experimental results also indicate that the proposed RFE has good performance in terms of fast dynamics and strong robustness.