Study On One Cycle Controlled DC Side Active Power Filter

A great amount of power harmonic is produced along with the development of power electronics and the wide application of power electronics equipments. Many people have paid much attention to correct power harmonic all over the world. Active power filter(APF) is regarded as an effective way to correct power harmonic. One cycle control theory developed since 1990s is a large signal and nonlinear technology, which features the goodness of simple circuit structure, high control precision, and fast responsevelocity. Active power filter moving from AC side to DC side is a new topology------ DCside active power filter, the active switch amount of which is half of APF's. One cycle controlled DC side APF is the combining of one cycle control theory and DC side APF, so which features the goodness of two technologies.In this thesis, one cycle controlled DC side APF is the main content. The operation principle of one cycle controlled DC side APF is analysed detailed in theory and researched in experiment.First, the control equation of DC side APF is deduced and some features of DC side APF are simulated. System compensation property dropping with the descending of load is found when simulation. In order to solve the problem, an improved one cycle controlled DC side APF is proposed. The steady and dynamic properties of the original and improved one cycle controlled DC side APF is analysed in theory. The results indicate that not only the compensation property is increased, but also the stabilization region is extended of the improved control method.Second, the relationship of the main circuit parameter and compensation property is analyzed and the estimate formulas to determine the main circuit parameter is given, which gives the theory foundation to design one cycle controlled DC side APF. By employing the proposed formulas, the proto type of original and improved control methods is founded and experimented with two different type loads. The experimental results meet with the simulation results and the theoretic analysis.At last, a proximate algorithm is proposed for calculation high frequency chopping switch current stress. By employing this proximate algorithm, the switch utilization ratios of three circuits(DC side active power filter, active power filter and power factor correction) for correcting power harmonic and improving power factor correction areanalyzed and compared in theory. From the view of switch utilization ratio, the theory gist is given for employing which circuit in condition with different total harmonic distortion of load current to correct harmonic current.