Harmonic Detection Theory And Method Study In The Active Power Filter

The requirements for power quality are more and more high in the modern production and life,and with the electronic devices widely used in modern power system, so a large number of harmonic currents infused into power system.This power pollution have a huge of harm to the safe operation of power systems and power users.Therefore all of countries in the world pay the sufficient concern to the harmonic problem.Many countries and international academic organizations have instituted the standards and requirements of power system harmonic wave and power equipment harmonic wave. In recent years, the study of harmonic control have further development,all of this attribute to the produce of new theoretical methods and new materials and the development of power electronics technology.However,each harmonic method has more or less limitations.Because of its own unique advantages of the active electric wave filter,it gets the great attention from the majority of scholars.The thesis introduces the relevant concepts, mechanism of production and influence of the electric hamonic wave at first, and also including the wave in harmony inhibits and the research current situation of the active electric wave filter, more detailed in exposition of the principles of the APF, the components, and the classified comparison of properties of APF. Based on analysis of the instantaneous reactive power theory of the harmonic current detection method, and applying the MATLAB simulation software construct the artificial circuit of harmonic current detecting and also study the effects upon low-pass filter to harmonic current detecting. The results showed that the rank, cut-off frequency and type of of low-pass filter all have significant effects to the dynamic response process of harmonic detecting circuit and the accuracy of measurement.This paper bring forward a new method of harmonic current detection based on the theory of neural network,it is better than the conventional instantaneous reactive power based on the theory of harmonics detection circuits in the both of detection accuracy and dynamic response. And the method has been verified that it is effective by the Matlab software.Finally,we put forward the future outlook for further research .