A New Fixed-Point Non-Integer Downsampling Method For High-Precision Harmonic analysis

Harmonic mitigation is a significant concern in industrial production and harmonic analysis plays a crucial role in power quality analysis. The achievement of accurate harmonic analysis and prevention of spectral leakage in the Fast Fourier Transform heavily relies on the utilization of synchronous sampling. This paper proposes a Fixed-point Non-integer Down-sampling method, which enables dynamic downsampling while maintaining a fixed sampling rate. Based on this method, an Field Programmable Gate Array (FPGA) based architecture for synchronized downsampling in harmonic analysis is presented, which resolves the contradiction between the power computation requirements at high sampling rates and the synchronous data acquisition needs for harmonic analysis. The architecture is verified by experimental tests, demonstrating harmonic amplitude and phase accuracy with a relative error of 10
⁻⁷
.