Synchronous detector and voltage flicker signal detection based on wavelet transform

A new type synchronous detector is proposed, which consists of a multiplier and a subband filter constructed by wavelet multiresolution signal decomposition. By using the wavelet synchronous detector, a new method is proposed to detect the envelope signal and the modulating signal without distortion, and detect the abrupt change time of voltage flicker accurately. Furthermore, wavelet multiresolution signal decomposition is included in this method to decompose the envelope signal (or modulating signal). Wavelet expansion coefficients are used to calculate the energy and the root mean square (RMS) value of each subband, and to reconstruct the frequency components of the envelope signal. Consequently, the time-frequency characteristics of the voltage flicker signal can be shown clearly. Simulation results prove the validity and superiority of this method.