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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. [ABSTRACT FROM AUTHOR]

• The proposed method is suitable for more electric aircraft grids. • The proposed method has fast dynamics. • The structure of the proposed method is simple. Different from utility power systems, the grids of more electric aircraft (MEA) are frequency-variable, and the frequency change range is from 360 Hz to 800 Hz. Most grid synchronization methods are designed for constant-frequency grids whose frequency varies in a small range around 50 Hz or 60 Hz. Therefore, the dynamic performance of these methods decreases considerably in MEA grids. In addition, the frequency in MEA is higher than that in utility power systems. Grid voltage parameters are thus required to exhibit a fast dynamic response. To resolve this problem, this paper proposes an algebraic method to estimate the positive- and negative-sequence components (PNSC) of grid voltage accurately. By analyzing the relationship between grid voltage and its time delay signals, the linear regression model is established. Then, grid frequency, PNSC are obtained with an algebraic method. The proposed method relies on algebraic operations only and thus exhibits a fast dynamic response. Experiment results verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]