Research On Harmonic And Inter-Harmonic Detection Algorithms Based On DSP

With the rapid development of technology and modern industry, the electricaldemand has been increasing for all trades and professions. A variety of volatile andimpact electrical load are being used, which leads to the increasing proportion of non-linear load in the grid. As a result, more and more harmonic and inter-harmonic currentcome into being. Therefore, the waveform of sinusoidal voltage has been changed,which reduces the power quality. Meanwhile, power users are proposing higher powerquality. That is why harmonic problem becomes an urgent problem. As the premise andbasis of harmonic problem, harmonic detection is of great significance.This paper pays great attention to the research on harmonic and inter-harmonicdetection, and focuses on the detection method of FFT and wavelet analysis bymeans of theoretical analysis and simulation experiments. It offers the analysis processon the advantages and disadvantages of traditional FFT, interpolating windowed FFT,wavelet transform, wavelet package transform and continuous wavelet transform. Onthis basis, the paper proposes Nuttall FFT and wavelet-packet-traversal-filter algorithms.Four different kinds of signals that contain harmonic and inter-harmonic waves areanalyzed separately through MATLAB simulation. According to the analyzed results,the paper discussess the application and feature of each analysis method, and draws aconclusion that each method has its own advantages in different situations. The gridsignal should be detected and analyzed by wavelet analysis because of its volatility andimpaction.Taking into account the realization of algorithms and the practicality of gridmonitoring, this paper describes a particular introduction of the design for powerparameters analysis based on DSP(TMS320F2812) at the views of hardware andsoftware. The hardware system can function well on the measurement of basic powerparameters (voltage, current and frequency), the calculation of power parameters(powerand power factor), the analysis of harmonic and inter-harmonic proportion, and thehuman-machine interaction. This paper not only gives a detailed description about thestructures and functions of hardware platform, but also offers the software design basedon the modular programming idea. In order to meet various monitor situations, itachieves the transplanting of two harmonic and inter-harmonic detection algorithms tothe hardware platform. The overall debugging results show that the picked detectionalgorithms can meet the balance between monitoring accuracy and real-timeperformance.