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Electrical and electronic engineering
This paper studies the phase and frequency estimation problem of single-phase grid voltagesignal in the presence of DC offset and harmonics. For this purpose, a novel parameterized linear modelof the grid voltage signal is considered where the unknown frequency of the grid is considered as theparameter. Based on the developed model, a linear observer (Luenberger type) is proposed. Then usingLyapunov stability theory, an estimator of the unknown grid frequency is developed. In order to deal with thegrid harmonics, multiple parallel observers are then proposed. The proposed technique is inspired by otherLuenberger observers already proposed in the literature. Those techniques use coordinate transformation thatrequires real-time matrix inverse calculation. The proposed technique avoids real-time matrix inversion byusing a novel state-space model of the grid voltage signal. In comparison to similar other techniques availablein the literature, no coordinate transformation is required. This significantly reduces the computationalcomplexity w.r.t. similar other techniques. Comparative experimental results are provided with respect to twoother recently proposed nonlinear techniques to show the dynamic performance improvement. Experimentalresults demonstrate the suitability of the proposed technique.
Ahmed, H. et al (2020) Coordinate Transformation-Free Observer-Based Adaptive Estimation of Distorted Single-Phase Grid Voltage Signal, April 2020 IEEE Access PP(99) DOI: 10.1109/ACCESS.2020.2988711