Research On Active Power Filter Based On Adaptive LMS

In recent years, due to the rapid improvement of modern scientific research level, process level of power electronic devices get rapid development, a corresponding semiconductor device to meet the industrial transformation of electrical energy demand, the same to the electric power system caused should not be ignored in the harm of harmonics. The power supply quality serious decline, a threat to the safety of electric power system. Active power filter is a can realize dynamic and real-time harmonic resistance, new power electronic device of reactive power compensation, to make up for the shortcomings of the traditional passive filter, so it has been paid much attention.This paper describes electric power system of harmonic the definition, source and harm of power supply network, expounds the active power filter historical progress, international and our country of harmonic research and common classifications, briefly introduces the current harmonic current detection of commonly used algorithm.Harmonic detection as a measure of one of the key processes of the work performance of active power filter, this paper in the traditional adaptive harmonic current detection algorithm based on, considering the traditional algorithm in step for a certain value and need to consider the algorithm between the calculation speed and calculation accuracy of the contradiction, this kind of to reduce algorithm is used. Therefore, in this paper improved design a new improved variable step size adaptive harmonic detection algorithm, by Sliding Integrator filter to the feedback signal inside the high-order components, with real error signal to adjust the weights change, enhanced detection accuracy, and by increasing the dynamic factor to adjust the step size, so as to improve the harmonic detection of the speed of dynamic response and steady-state accuracy. After the algorithm simulation, its correctness is proved.The working principle of shunt active power filter are briefly introduced, and focuses on the analysis of DC side capacitor voltage control strategy by using the theory of instantaneous reactive power method, from the energy of the active power filter in the AC side and DC side transmission angle analysis, proposed on DC side voltage control of the improved method, and its mathematic model is established, and the combination of the improved adaptive harmonic detection, can effectively maintain the stability of the DC side voltage of filter.Finally, the selection of key parameters of the whole system are analyzed, the simulation of shunt active power filter model using MATLAB/SIMULINK simulation. The result of simulation shows that the improved algorithm proves the validity of the algorithms presented in the paper.