Research On Dual Phase Shift Control Of Double Active Bridge Bi-directional DC-DC Converter

Dual active bi-directional DC-DC converters have attracted the attention of many experts and scholars in recent years because of their potential use in distributed power generation systems,energy storage systems and intelligent microgrid construction.Because of its high power density,high efficiency,zero voltage switching and modularity,this type of converter is of great significance for its research.The bi-directional DC-DC converter studied in this paper consists of a half-bridge three-level circuit,a full-bridge circuit and a high-frequency isolation transformer.The biggest advantage of this topology is that all the switching tubes on the primary side of the converter only need to withstand half of the input voltage,which is suitable for high-voltage and high-power applications.Since the converter is under the traditional single phase shift control,the converter will generate a large return current and current stress,thereby reducing the transmission efficiency of the converter.In order to solve this problem,this paper mainly optimizes the control of the converter.The main contents of this paper are as follows:Firstly,by analyzing the working principle of the converter during single phase shift control,the working characteristics of the converter are studied,and the transmission power,return power and current stress expression of the converter are obtained,and the visualization is made.In order to solve the large reflow power and current stress in the converter,this paper proposes a new dual phase shift control strategy with the optimal reflow power as the target.When transmitting the same power,by comparing and analyzing the soft switching range,return power and current stress of the converter under different control modes,it can be known that the converter adopts the new dual phase shift control,whether it is the converter current stress or the switch tube ZVS.The working range is better than double phase shift control and single phase shift control.Secondly,the simulation model of the converter is built in MATLAB,and the system simulation is carried out according to the parameters of theoretical analysis.The simulation results are consistent with the theoretical analysis,which verifies the superiority of the new dual phase shift control strategy.Finally,a test prototype with a rated power of 160 W was built for verification.By observing the current stress and return current of the converter under single phase shift control,double phase shift control and new double phase shift control,the converter can be known.When using the new dual phase shift control,the transmission efficiency of the converter is better than the remaining two controls.The experimental results verify the correctness and feasibility of the new dual phase shift control.