Research On Detection And Control Of Three Phase Power Quality

As a kind of important energy,power is serious relations to the development of the national economy and the social progress of science and technology.In recent years/with the rapid development of science and technology,a large number of nonlinear control devices are widely used in industrial and agricultural production and people's daily life,which produced a lot of voltage disturbances and the harmonic interference.In addition,some equipment is more sensitive to the voltage flucations,which makes the power quality do not meet the demand of users.With the problem has become increasingly prominent,the people are also getting more attention to the power quality.If want to improve the power quality,we must find a kind of effective detection and control method to improve the power quality for purpose.At present,the research of power quality in terms of detection and control have achieved excellent achievements,but there is still great space for us to research. It has certain social and economic significance for the research for the method of detection and control.In this paper,the main purpose of this research on the method of detection and control which based on the three-phase power quality is:by finding an effective detection algorithm,identify different disturbance information of power quality and carries on the disturbance classification.By finding the problem of the disturbance waveform of power quality, to find a control method that according to the analysis results to improve the power quality and promote the development of the national economy and construction. Therefore,the research has important practical and broad application prospects for the development of the social economic.The paper mainly includes the following contents:(1) Reading a large number of domestic and foreign relevant literature, investigating the existing power quality compression method.Analysis of the basic principle and advantages and disadvantages of each algorithm.Combined with the characteristics of the three-phase power quality data and compared of various methods.Finally using the method of compressing data for three-phase power based on adaptive two-dimensional wavelet packet for data preprocessing,arrd verified the effectiveness of the method through the simulation.(2) According to the characteristics of disturbance waveform structure for the power quality,combined with the method of dq transform and ANN to research on the power quality disturbance detection.And optimized the algorithm on the basis of this.This paper presents a method of dq transformation and ANN based on a algorithm of mathematical morphology filter.After adding the mathematical morphology filter,it is effective to filter the noise and the interference of harmonics,and improve the accuracy of harmonic identification.At the same time,it confirmed the feasibility and superiority of the algorithm through the simulation.(3) Analysis the reason of harmonics and various control method of harmonic theory in recent years.Through analyzing the comparision of various method,using the power supply current predictive control algorithm to control the harmonic.Based on this,this paper optimized and improved PI control algorithm in the DC voltage side.The improved method of PI control has better effect of compensation and dynamic performance.Through analysising and comparing the experiment,finally verify the effectiveness and superiority of the improved algorithm.(4) To summary the paper and discuss the next step of work.