Abstract: A method, apparatus and computer readable medium for estimating a frequency of an electrical signal are disclosed. The method comprises taking a number of samples of an electrical signal throughout a main sampling window; dividing the number of samples taken throughout the main sampling window into a plurality of groups of consecutive samples, each group of consecutive samples forming a subwindow, wherein each subwindow includes a minimum number of the number of samples required to provide a required level of accuracy for estimating the fundamental frequency of the electrical signal; estimating, for each subwindow, the fundamental frequency of the electrical signal based on the group of consecutive samples of the respective subwindow; and determining if the fundamental frequency is stable throughout the main window by comparing the estimated fundamental frequency of each subwindow.

Abstract: This disclosure relates to an apparatus, computer readable medium and a method for estimating a frequency of an electrical signal. The method comprises converting a first signal having three components into a second signal having two components in accordance with a first transformation, wherein each component of the first signal corresponds to a phase component of a three-phase electrical signal and the two components of the second signal are representative of characteristics of the three-phase electrical signal. The method further comprises filtering the second signal in accordance with a previous frequency estimation. Then the method comprises converting the filtered second signal into a third signal having a single component in accordance with a second transformation, wherein the single component of the third signal is representative of characteristics of the three-phase electrical signal.