Single-phase Parallel Active Filter Based On Three Level Dual Buck Full Bridge Inverter

With the rapid development of power electronic technology and the wide application of power electronic devices, harmonic pollution is becoming more and more serious. At present, there are two main ways to solve the problem of electric power harmonic pollution. One kind is "prevention" method which reduces the harmonic by optimizing the product performance. The method reduces the harmonic source pollution to power network by improving the performance of electric equipment. But the power systems are very complex, the switch working state of power electronics device used in the power grid inevitably produce larger harmonic pollution. So the another way by installing harmonic suppression device in power grid must be adopted.Passive and active power filter are the two kinds of harmonic suppression device. Although the passive power filter has simple structure, high reliability, low operating cost, its efficiency is low and the performance of dynamic compensation is poor. So, passive power filter is gradually replaced by the excellent active filter. On the basis of the traditional Active Filter design, the tri-level dual Buck full bridge inverter is used as the main topology to implement modular Active Filter(Active Power Filter, APF) function in this study. In this paper, at first, we analyzed the main topology scheme in a variety of active filter, and summarized the advantages and weaknesses of the various topologies. The paper demonstrates that when the tri-level dual Buck full bridge inverter is used as the main topology, there is no shoot-through problem and no reverse recovery problem of the body diode of power switch which reduces the switching loss and optimizes the system efficiency. After that we select the best detection and control scheme for system. Then the paper respectively expounds the design of hardware and software part of this study. Finally, the paper gives the main test results of the principle prototype in this study and puts forward the corresponding improvement plan.According to the study of the experimental test results, it shows that: the principle of active filter prototype that is designed in this topic is not only satisfying the indices such as output power, harmonic content and THD of every phase, but also has a good stability and the Man-Machine conversation function.