Group-Delay-Controlled Multiple-Resonator-Based Harmonic Analysis

Abstract

In this paper, a modified and improved approach to the recently proposed multiple-resonator-based observer structure for harmonic estimation has been proposed. In the previous papers, two inherent particular cases have been considered. In the first case, estimation is performed in the point located in the middle of the observation interval, and exhibits good noises and unwanted harmonics attenuation but possesses a large response delay. In the second case, the estimation point is at the end of the observation window. In this case, the filters are able to form a zero-flat phase response about the operation frequency and hence able to provide instantaneous estimates, but with large overshoots caused by resonant frequencies at the edges of the pass band, and the high level of the sidelobs. In this paper, the estimation point is shifted along the observation interval reshaping frequency responses to tradeoff between those opposite requirements. The effectiveness of the proposed algorithm is shown through simulations.