Four harmonic analysis and energy metering algorithms based on a new cosine window function

In order to further improve the calculation accuracy of the windowed fast fourier transform (FFT) interpolation algorithm, this study proposes a four‐order Hanning self‐multiplication window, and based on this new window function, four kinds of windowed FFT interpolation algorithms for harmonic analysis have been derived, include single‐spectrum‐line interpolation, double‐spectrum‐line interpolation, triple‐spectrum‐line interpolation and four‐spectrum‐line interpolation. Using these four harmonic analysis algorithms, the amplitude, phase and frequency of the fundamental and harmonic in the measured voltage and current signal can be obtained, and then the fundamental and harmonic energy can be calculated accurately by using the energy metering equation. The simulation results show that the window function has better main lobe and side lobe performance, which can effectively suppress the influence of spectrum leakage and fence effect, so based on this window function, the four harmonic analysis and energy metering algorithms can inhibit the effect of fundamental frequency fluctuation, and with the number of spectrum lines increasing, the computing accuracy of the algorithm is improved.