Optimal Control Of Dual Active Bridge Resonant Converter Based On Asymmetric Tap Transformer

With the improvement of power grid and the widespread application of electric vehicles,more and more attention has been paid to the research of electric vehicles.Among them,Dual Active Bridge(DAB)is widely used in the field of electric vehicles because of its simple structure,high power density,soft switching and bidirectional energy flow.Therefore,in-depth study of the potential advantages of this kind of topology and efforts to improve its transmission efficiency and power density are of great significance to improve energy efficiency and reduce the consumption of non-renewable resources.In this paper,the application background and research significance of the dual active bridge converter are given firstly.The typical topology and classical control mode of the converter are briefly introduced.Then the dual active bridge series resonant converter(Dual)is summarized.Active Bridge Series Resonant Converter(DBSRC)research status of topology and control strategy;due to existing research,DBSRC based on asymmetric tapped transformer has larger power transmission range than traditional DBSRC under the same phase shift modulation,voltage gain And the soft switch range is also wider.Therefore,this paper takes the double-active bridge series resonant converter based on asymmetric tapped transformer as the research object.After a brief introduction to the basic characteristics of the dual-active bridge series resonant converter based on the asymmetric tapped transformer,the topology is simplified and a mathematical model is established to obtain the steady-state expressions of active power,reactive power and voltage gain.Then the influence of topological parameters on active power,reactive power,soft switching,and the effect of reactive power on the transmission efficiency of the converter are analyzed.The reactive power of the converter is taken as the objective function to be optimized,the active power expression is taken as the equality constraint condition,and the soft switching expression is taken as the inequality constraint condition.After appropriately simplifying the objective function,a control strategy to minimize reactive power is proposed,which aims to ensure that zero-voltage switching(ZVS)and reactive power minimization can always be achieved when the converter transmits any active value.Then,according to the reactive power optimization control flow chart,all the optimal reactive power control points in a certain voltage and power range are obtained by programming software,and these control points are recorded in the table with voltage as row and power as column.Finally,the controller can index the optimal control points by looking up the table.Then a complete system control scheme is given,and simulation software is used to verify the feasibility of the control strategy.At the same time,in order to illustrate that the control scheme may be applicable to other converters of the same type,a control flow suitable for this topology is designed by taking the traditional LC DBSRC as an example.Finally,the parameters of the main circuit are analyzed and selected.The design process of the magnetic components required by the experimental platform and other device selection processes are given.The control strategies proposed in this paper are analyzed and verified by simulation and experiment.