Research On Loosely Coupled Inductive Of Full-bridge Resonant Converter

Loosely coupled inductive power transmission is a novel power transfer technology, which is based on electromagnetism and coupling theory, modern power transform technology. And it realizes the non-contact power transfer between power source and load equipment.The paper selects full-bridge resonant converter as the main topology and gives theoretical analysis and experimental verification of this novel technology.Firstly, the characteristics, present status, and research direction of loosely coupled inductive power transfer technology are presented. And the application of this technology to high power electric vehicle charging is given.Secondly, the loosely coupled transformer, which acts as the interface between take-apart primary source and secondary load, is studied. The influence of loosely coupled transformer on power transfer capability, over all efficiency and system performance is analyzed. And a novel winding strategy is put forward, and it can provide a larger coupling factor than conventional winding strategy. The simulation analysis based on ANSYS Emulation environment and test results validate the feasibility of the novel winding strategy.The large gap in loosely coupled transformer brings a high stress on the switch, and impacts power transfer capability, and thus reduces the overall efficiency. Through analysis, proper compensation can reduce the above-mentioned influences of the large gap to an accepted level, and increases the feasibility of this novel power transfer means.Due to the addition of the compensation units, the bifurcation phenomenon probably appears, and the system goes into the unsteady state. Thus, the bifurcation is analyzed in detail, and the conditions avoided the bifurcation is deduced.Similar to loosely coupled transformer, the load change also has a great influence on system control and performance. Through comparison, the characteristics of full-bridge converter with load under different compensation strategies is revealed, and it provides a guideline to the proper choice of compensation topology for different applications.Finally, a prototype of full-bridge converter with loosely coupled transformer is fulfilled. The power transfer capabilities under different conditions are characterized, and the overall efficiency is also given, which verify the correctness of the analysis and the conclusion given in previous chapter.