Design And Control Of Bidirectional DC/DC Converter In DC Microgrid

In recent years,with the development of renewable energy and electric vehicles,DC microgrid has attracted more and more attention.Due to the limitation of traditional AC power grid,the research of DC microgrid is not as deep as AC microgrid.But compared with AC microgrid,DC microgrid is more friendly to access distributed power supply.The increasing DC load also makes it more efficient to integrate distributed power supply,load and energy storage system in the form of DC microgrid.Bi-directional DC/DC converter is an important component to realize bidirectional energy flow in DC microgrid energy storage system.It plays an important role in improving the power quality of DC microgrid and enhancing the reliability of DC microgrid.Therefore,it is worth studying.This design mainly studies the bidirectional DC/DC converter of DC microgrid energy storage system.Firstly,the research discusses the research status of DC microgrid and bidirectional DC/DC converter,and the principle of the selected bidirectional DC/DC converter topology is analyzed.In view of the bus voltage control target,it is pointed out that the converter uses DC bus voltage as the outer loop in buck mode,and adds current inner loop in order to limit charging current.In boost mode,in order to improve the inertia of the system,virtual inertia control strategy can be introduced.Because the setting of virtual parameters is more flexible,virtual parameters can be adjusted according to the actual situation of DC bus voltage to achieve better control effect.According to the proposed control strategy and the small signal model of the converter,the relevant parameters of the controller are designed,and the different operation modes of the converter are simulated and analyzed by using simulink.Finally,in order to build the experimental platform of DC microgrid,the hardware circuit of bidirectional DC/DC converter is designed,the specific parameters of the main circuit and auxiliary circuit are calculated and selected,and the relevant program is compiled according to the proposed control strategy,and the proposed control strategy is verified by experiments.The simulation and experimental results show that the bidirectional DC/DC converter can achieve the goal of stabilizing DC bus voltage under different operating conditions,and the virtual inertial control can achieve better control effect.