Research Of FPGA-Based Power Harmonic Signal Detection

This paper mainly studies the problem of harmonic detection of power system.Because the power electronic equipment in the electrical railway, petrochemical,metallurgical, widely used in coal industry, the power system harmonic contentincreased, seriously affecting the safe operation of power grid and power quality, hasaroused widespread concern in the community. Harmonic detection is an importantaspect of harmonic problem in power system, is the basis to solve other harmonicproblems, so the power harmonic effective real-time detection has a certain theoreticalsignificance and practical value.Comparison of various harmonic detection method based on the study, thispaper based on the fast Fu FFT is widely used in the harmonic detection method, andthe field programmable gate array (FPGA) chip to realize FFT processor. Accordingto the fence, the inevitable effect of harmonic detection of spectrum aliasing andspectral leakage mechanism analysis method, hardware circuit using PLL frequencymultiplier circuit and low pass filter with improved harmonic measurement. Thispaper gives a general hardware design of harmonic detection system, including signalconditioning circuit, A/D conversion circuit, frequency tracking circuit, PLLfrequency multiplier circuit and peripheral interface circuit, and the function andworking principle of each module is introduced in detail.In addition, this paper focuses on the research of FPGA data processing unit,introduces how to realize FFT processor with FPGA. In the analysis and comparisonof various FFT algorithms, the time-domain extraction algorithm based on-2as theimplementation algorithm of the FFT processor, the design of a high efficiency of thecomplex multiplier, can control the utilization rate of resources under the premise ofthe chip effectively reduce the complexity of algorithm.Finally, using the QuartusII and Modelsim are FFT processor simulation, resultsshow that the FFT output structure and output Matlab model, under the environmentof FPGA simulation waveform error is small, high calculation speed, fully meet theharmonic detection of high speed data processing design requirements.