High-precision time-domain convolution in harmonic detection

In this paper, a time-frequency filter is designed, which can detect the frequency, amplitude and phase of any order harmonics and interharmonics in signal by means of time domain convolution. Negative half-axis frequency is restrained with Hilbert transform. The theory analysis are carried to this method and the calculate formula are concluded, the spectral leakage and the barrier domino offect are shun, the non-integer order wave are eluded, which are engendered in Fourier domain. Experiment simulation results show that time-frequency filtering convolution flunction can be designed and realized neatly and be real-time implemented conveniently in engineering application; the influences of fundamental frequency fluctuation on harmonic analysis are restrained by using the approach presented in this paper; the calculating frequencies with many order harmonics and interharmonics are nicety, the amplitudes and the initial phases are detected in high-accurately.