Dynamic Frequency and Amplitude Estimation for Three-Phase Power Systems

Graduation date:2018Several frequency and amplitude estimation algorithms are presented for balanced and unbalanced three-phase power grid systems. All the estimators are dynamic in nature and are implemented in the complex domain by transforming the three-phase power signals using Clarke’s transform. Specifically, we first construct a non-linear dynamic model of the complex representation of the three-phase voltage (fundamental frequency components and harmonics) and then we use the unscented Kalman filter to estimate both the magnitude and the fundamental frequency and its harmonics. The performance evaluation of the algorithm shows the accurate tracking accuracy and convergence time when the frequency and amplitude of the grid voltage waveform change continuously or abruptly. Comprehensive simulations are implemented for both balanced and unbalanced conditions based on the real-world power grid system data. Specifically, 4 types of input amplitudes and 2 types of frequency changes are applied to test estimation algorithm performance