A Parallel Hybrid Active Power Filter

With the rapid development of the electronic technology, a deal electric equipment has been applied in each field and it results in many accidents such as switch trip, massive blackout and so on. Therefore, how to deal with the harmonic pollution becomes a realistic research subject.The advantage of active power filter as a restraining dynamic harmonic power electronic device is incomparable. The detecting algorithm of harmonic current, method of current control and the compensation character to harmonic resources of the active power filter is studied in this paper. It provides the basic theory and reference value for the parallel hybrid active power filter which has lower cost and higher performance. Details are as follows:First, the harmonic current detection method based on instantaneous reactive power theory is mainly researched, and then an improved i p ? iq detecting method is proposed which is suitable for the parallel hybrid active power filter. APF can be put into use at any time in this method.Secondly, comparison of various tracking control method to converter current are analyzed. The advantages and disadvantages of each are summarized. Triangle wave comparison current control is used in this paper. It is verified by simulation.Thirdly, occurrence of resonance in LC filter is analyzed then principles and steps are proposed to design of passive parameters. The active algorithm is described in detail such as capacity of the main circuit, DC bus voltage, DC side capacitor design.Fourthly, a soft start approach is designed based on the features of PHAPF. The overall system is analyzed by MATLAB/Simulink. The results of simulation show PHAPF system is effective and can reduce costs effectively. Besides, it has some practical value. The correctness of the program is verified.