A Wideband Synchronous Sampling Method for Power Analyzer

In the power analyzer, synchronous sampling is needed to achieve high precision power and harmonic calculation. And the fundamental frequency measurement is important for synchronous sampling. However, due to the existence of harmonic components in the voltage/current signal, it is difficult to accurately measure the fundamental frequency of the signal for the traditional frequency measurement method. This paper proposes a new synchronous sampling architecture to realize the accurate fundamental frequency measurement for the signal. In the developed scheme, the frequency refinement method is adapted to solve the problem of signal discontinuity in discrete Fourier transform (DFT). Then the one-dimensional search method is used to accurately measure the fundamental frequency. In the experimental results, the synchronous sampling algorithm has a large signal frequency measurement range of 10 to 400 Hz with an error of less than 0.001 Hz + 0.01% * fundamental frequency. The wideband synchronous sampling proposed in this paper achieves high measurement accuracy.