Interpolated FFT Harmonic Analyzer for Power Systems, and System on a Chip (SOC) for It

This paper presents a System on a Chip based new harmonic analyzer (HA) for the power grid. As is increasingly evident, the power grid - comprising the traditional system and the emerging renewable systems, presents great opportunities for SOC research and applications in terms of sensing, control, and estimation of key parameters. All for massively distributed deployment in order to enhance the reliability and restoration capability of the future grid. We present a new algorithm from the power systems perspective and the realization from an SOC perspective. The algorithm pertains to a Harmonic Analyzer, based on Interpolated FFT, which performs well under a variety of conditions including steady-state, faulted power lines, sudden change in amplitude, sudden change in frequency, interharmonics, and low frequency hidden signal - all with high accuracy and relatively simple calculations. Moreover it enables the estimation of all three types of parameters of interest: frequency, phase, and amplitude, while also eliminating the need for pre-filtering. Simulations demonstrate success for all of the above mentioned important scenarios. In some applications where only the fundamental frequency parameters are of interest, a complete FFT is not warranted; only the Fourier series coefficients at two or three frequencies suffice. The SOC would perform three functions: sensing, computing, and outputting the results. The paper discusses the algorithm, its performance comparison with other approaches, and the SOC architecture.