Detection And Analysis Of Harmonics And Inter Harmonics Based On Multiphase Filter Banks

In recent years,with the wide applying of power electronics devices,the power quality problems have become more serious,especially the harmonics and inter harmonics problems are more obvious.Through real-time and accurate detection of harmonics and inter harmonics parameters,the optimal configuration of harmonics compensation device and the purpose of harmonics and inter harmonics control can be achieved.The structure of the basic multiphase filter banks is analyzed,and the rationality and validity of the method are deduced and proved by mathematical method.An optimized multiphase filter banks structure is proposed to solve some problems in the structure of multiphase filter group: blind area problem,signal decision problem and data processing rate problem.The optimized multiphase filter banks can better deal with and coordinate the data rate of each part and give full play to the advantages of the multiphase filter banks structure.The noise analysis of the channel proves that the method can effectively reduce the mutual interference between the detection signals,and provides a theoretical basis for the detection threshold.The four correction methods(ratio method,energy center of gravity method,phase difference method and all phase method)are analyzed amply.In the case of different SNR and different frequency resolution,the performance of four correction methods in correcting different parameters is obtained by a large number of Monte-carlo computer simulation experiments,and four kinds of correction and the algorithm complexity of the method are analyzed.By using the principle of optimal path,the formula of optimal selection weight is derived.By comparing the optimal selection weights,a more appropriate correction method is selected,and the effectiveness of the method is verified by simulation.The key technology of the multiphase filter banks and the correction method is fused to form a more perfect detection system of harmonics and inter harmonics.The harmonics and inter harmonics detection methods designed in this paper are simulated and analyzed to verify the effectiveness of the method.