| Popis: |
Voltage sag belongs to a kind of transient power quality problems, it possesses short mutations, non-stationary characteristics and the detection on the interference is difficult. Wavelet transform is a better signal analysis method and it is very suitable for analysis of mutations in the signal. Compared with traditional wavelet transform algorithm, Wavelet transform algorithm does not depend on the ascension of the Fourier transform and it reduces the computation complexity, so it is very suitable for hardware implementation. This paper introduces a design based on 9/7 of lifting wavelet transform of the voltage sag detection algorithm, and realized in the FPGA and modeling the transient power quality signal in the Matlab. To make hardware implementation easier, a series of optimization to the coefficient of ascension of 9/7 of lifting wavelet transform was carried out. The results show that 9/7 of the lifting wavelet transform algorithm can effectively test the end time of the voltage sag happens. |
