The Research On The Electro-magnetic Components Integration In The Grid-connected Inverters

With widespread use of new sources,especially the solar energy,tremendous photovoltaic grid-connected inveters play an important role to realize the power conversion.As to distributed generation system,sometimes,power density of the system is same important as the conversion efficiency as a crucial performance indicator,when the environment and installation condition of the grid inverter are taken into consideration.Thus,its meaningful to improve the power density of the grid-connected power applications.According to the inverters proposed in this paper,to optimize the space occupied by the passive components including output filters,transformer and capacitor in these topologies,etc.several integrated structures proposed based on flexible multi-layer foil(FMLF)technique,with proper integrated magnetic circuit design,the total volume of these passive components had reduced.In the first chapter,focusing on power density,starting from introducing the development of new industries and new energy sources,the influence of new topologies and new devices on power density of converters is introduced.Next,aiming at the optimization of the volume of passive components in the system,the magnetic circuit integration technology is presented at first.Then,two kinds of passive components integration technology: PCB integration technology and flexible multi-layer foils integration technology are introduced,and the characteristics of these two techniques are described respectively.Then,related to the design in this paper with FMLF technique,the revelant problems about the structures of the integrated design,the distributed components model for the FML foils are introduced in detail.The significance of optimizing the volume occupied by passive components in the inverters is also explained.Inverter is a very important link in the process of electrical energy transformation.The output filters and transformers in the inverters usually occupy a considerable volume due to the use of discrete components.From Chapter two to Chapter four,several passive integrated structures are proposed for the output filter,the output filter and transformer in the inverters with FMLF technique.By establishing the distributed electro-magnetic model,the transmission characteristics of the integrated structure can be estimated with relatively high accuracy when different terminals of the structure are connected to outer circuit.Proper magnetic circuit integration design is used to further reduce the space taken by the proposed design.Then,prototypes are established and the performances are verified by the experiments.Finally,the main contribution of the thesis is summarized.The further works are presented.