| Compared with AC transmission,HVDC has the advantages of low cost and low power consumption,it has been a hot topic for domestic and foreign scholars.In recent years,with the rise of distributed power and electric vehicles,more and more attention has been paid to the DC micro-grid.DC micro-grid can effectively integrate various distributed power supplies,loads,energy storage devices and energy conversion devices together,and it will be an important model for future power supply.The bidirectional DC/DC converter plays a role in realizing the energy flow between the distributed power supply and the DC bus,so it has a good prospect.On this background,this paper discussed the current situation of DC micro-grid at home and abroad,and also introduced the topology of bidirectional DC/DC converter.Then this article analyzed the working principle of the bidirectional full bridge DC/DC converter,and calculated the parameters of the main circuit power device,also designed the control circuit related to the converter.In order to get the system transfer function,the mathematical model of bidirectional full bridge DC/DC converters was established based on the small signal model of Buck and Boost converters.According to the type of converter system function,the theoretical analysis and the SISOTOOL tool in Matlab were used to design the PI controller of the system,and the closed-loop system simulation of the converter was realized in Matlab/Simulink.Finally,the bidirectional full bridge DC/DC converter was connected to the DC micro-grid experimental platform.The experimental result showed that the bidirectional full-bridge DC/DC converter could increase the voltage of the energy storage device or decrease DC bus to the target voltage.It could also coordinate with other DC/DC converters,making the DC bus voltage stability in a certain range. |
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