Adaptive Frequency Estimator Based on the Observable Canonical Form

This paper proposes an adaptive frequency estimator based on the observable canonical form. The signal model is first constructed in the form of the state space representation and transformed into the observable canonical form. The state observer of the signal model is then designed based on the observable canonical form. In addition, the structure of the observer is analyzed in detail with respect to the number of the frequency components. The design of the frequency-related parameters in the observer is also given in a theorem, based on which the adaptive frequency estimator is proposed with three main parts including an adaptive observer, an auxiliary filter and a frequency estimator. The proposed adaptive frequency estimator is finally validated on the simulated voltage signals with different harmonics for power quality monitoring.