Study On Novel Y-source Bidirectional DC-DC Converter

Nowadays,with the rapid development of the world economy,the storage of fossil energy such as coal and natural gas are decreasing day by day,and the environmental damage is becoming more and more serious.Under this background,the demand for new energy technology is getting higher and higher.As the key equipment of electrical energy conversion,the research of bidirectional DC-DC converter is widely concerned by experts and scholars at home and abroad.Bidirectional DC-DC converter is an important part of power electronic technology.It can realize bidirectional power flow and adjust voltage according to demand.However,the traditional bidirectional DC-DC converter still has some defects,such as insufficient boost capacity,dead time,discontinuous input current and so on,which seriously limits its application range.Compared with the traditional bidirectional DC-DC converter,Y-source bidirectional DC-DC converter has the advantages of simple structure,high boost capacity,flexible voltage regulation mode and so on.It has been a research hotspot in this field in recent years.First of all,this thesis analyzes the shortcomings of the traditional bidirectional DC-DC converter,enumerates the working principle,advantages and disadvantages of the traditional Z-source and the Quasi-Z-source bidirectional DC-DC converter,and provides the idea for the design of the new topology.According to the problems of discontinuous input current and large leakage inductance in Y-source topology,two novel Y-source bidirectional DC-DC converters are designed,in which input inductor is added to ensure the continuity of input current and higher boost capability.The working principle is analyzed respectively and the expression of equivalent circuit diagram under different conditions is formulated,and the boost factor and capacitor voltage stress are deduced,and compare five converter characteristics.Secondly,the state space averaging method and the small signal method are used to analyze the main circuits of the two new Y-source bidirectional DC-DC converters.The small signal model is established,the transfer function is derived,and the output voltage closed-loop control strategy based on capacitor voltage feedback is designed.Finally,according to its working principle,the parameters are designed,and the simulation of the converter is carried out with MATLAB/Simulink software,and the experimental prototype is built.Combined with simulation data and experimental data,it is compared with theoretical analysis.The correctness of theoretical analysis,formula derivation and validity of converter are verified.