Research On Harmonic Detection And Control Method Of Active Power Filter

With the harmonic control technology becomes more mature, the appeared active power filter will replace the traditional passive filter device gradually, it is a new power electronics device which eliminate harmonic and compensate reactive power, many performances are emerging in practical application, the fast response, the compensation effect and dynamic compensation has a strong advantage. In order to achieve the better performance index of active power filter harmonic filtering, this paper will be optimization and improvement in two aspects of harmonic detection and control strategy of active power filter.Research on a new type of harmonic detection algorithm. In the traditional LMS adaptive algorithm to meet precision requirement by increasing the step size in general, but steady wave also follow change obviously, harmonic-component detection cannot accurately and fast. In view of this shortcoming, proposed a new harmonic detection algorithm. The algorithm by means of active signal separation of original error, to obtain the actual error filter, the tracking error signal as the input of fuzzy controller, the step size has a strong ability following system change, can obtain better tracking results in a shorter period of time, and the tracking precision is improved greatly. The output field values of thickness division, make the system has smaller in the fluctuation.Real time adjustment of hysteresis current control method. In order to make the compensation current can change with the command current signal, make up the traditional hysteresis control method and its shortcomings, this paper put forward the control method of variable ring can keep track of the instruction signal changes in the wider. The algorithm is based on the output of the inverter, the specific formula of the parameters used to calculate the width of ring, the ring width is always changing, and then send it to the more links, used to generate the corresponding PWM signals, switch main circuit response, then get the compensation current.In this paper, on the basis of the oretical analysis, the simulation of the proposed algorithm, the simulation results validate the accuracy of the harmonic detection and control strategy.