Real-time detection method for the digitalization of electrical signal frequency

Aiming at the requirements of frequency measurement performance by various operating working conditions of electric net and electric equipment, the invention provides a real-time detection method for the digitalization of electrical signal frequency, which mainly comprises, based on short-time Fourier transform, the steps that: 1) equal interval sampling is implemented on an electric signal and 2 segments in a sampling sequence are added with self-convolution window, and then discrete Fourier transform is performed to obtain an initial phase angle of each segment of signal; 2) in accordance with the difference between the phase angles of two segments of signal, frequency of the signal is estimated; 3) sampling frequency keeps unchanged and in accordance with the estimated frequency of the signal, length of the analyzed signal segments are self-adaptively determined; 4) real-time frequency of the electric signal is self-adaptively detected once again in accordance with the same step. The method is simple in realization, small in computing amount and large in frequency detection range, has excellent measurement accuracy and tracking velocity both during slow change and during fast change of the signal frequency and also has practical value in engineering.