A unified method for signal parameter estimation of arbitrarily
distorted single-phase grids with DC-offset
Abstract
A unified method is presented which allows to
estimate all harmonic components, DC-offset and fundamen-
tal frequency in arbitrarily distorted single-phase grids us-
ing a frequency-adaptive observer (FAO) consisting of modi-
fied Second-Order Generalized Integrators (mSOGIs), a DC-
Integrator (DCI) and a modified Frequency Locked Loop
(mFLL). DCI and mSOGIs are tuned by pole placement which allows for an
arbitrarily fast detection of DC-offset and harmonic components if the
fundamental frequency is known. If the fundamental frequency must be
estimated as well, a mFLL with Gain Normalization (GN), Rate Limitation
(RL), Anti-Windup (AW) strategy and low-pass filters (LPF) must be
employed. The effectiveness of the proposed FAO is validated by
experimental results and its enhanced performance is shown by
comparisons
to existing estimation methods.