Research On Harmonic Current Detection Technology Based On Improved LMS Adaptive

A lot of power electronic devices are being used in the power system, such as rectifier, inverter, switching power supply and so on. In the power system, using the nonlinear load let it inject a large amount of harmonics into the power system, so that the current waveform of the power system is distorted. The power quality of the electric power system has been seriously affected. In power electronics, the heat of the power system harmonic control is rising in recent years, especially for the study of active power filter, which makes it a new way to control the power system harmonics. But how to through the improvement of key control algorithm for harmonic detection and current tracking algorithm of the two active power filter, so that the utilization efficiency of the active power filter is more efficient, and is still a hot topic of research.The accuracy and real-time performance are the most important indexes to test the filter performance of the active power filter. The accuracy of the harmonic current detection in power system is directly related to the performance of the system.Firstly, this paper introduces the definition of harmonic and its harm on electric power system, one of the most serious problems is the distortion of voltage and current waveform of power system due to harmonic injection into the current electric power system. Through the research and exploration of the harmonic control technology, the harmonic content is reduced to meet the national standard requirementsSecondly, this paper studies the most widely used active power filter type, that is, the shunt active power filter, and the mathematical model of APF is established, the principle of the harmonic current detection circuit and the principle of the current tracking control circuit are analyzed through the mathematical model.Again, in the harmonic current detection, the traditional detection principle, especially the instantaneous reactive power theory, which is the most important detection principle is discussed in this paper. The shortcomings of instantaneous reactive power theory are summarized, and the harmonic current detection algorithm based on LMS adaptive harmonic detection theory is proposed, which can improve the efficiency of harmonic current detection.Finally, in the simulation platform of three different harmonic current detection algorithm were programming and simulation, and set up the simulation model of shunt active power filter, through the simulation to verify the improved based on variable step size adaptive filtering algorithm for harmonic current detection and change in the traditional variable step filtering algorithm of harmonic current detection technology for the feasibility of power system harmonic filtering. The simulation results also prove that the improved algorithm is very significant to improve the performance of the active power filter.