A frequency measuring algorithm based on d-q-0 transformation

The traditional discrete Fourier transform based algorithm or the improved algorithm requires large quantity of data,and has complex computation,and poor dynamic performance,which is not easy to realize.A frequency detection algorithm based on three-phase power grid is proposed in this paper.This algorithm uses generalized d-q-0 transformation to transform the three-phase power into the d-q-0 stationary frame.Then each of the d-axis component and q-axis component is sent to a low-pass digital filter to get fundamental component.Through calculation of filtered fundamental component,the grid frequency could be obtained.There are lots of advantages of the algorithm,such as less of required data,easy to calculate and no consideration of initial phase angle.Matlab simulation shows that the algorithm is simple,easy to implement and able to fast track the system frequency with high precision.