Research On Performance Optimization Of Dualactive Bridge Converter Based On Triple Phase Shift Control

In the past ten years,the generation and demand of renewable energy have grown steadily,and electric vehicles powered by renewable energy have also received more and more attention.The Dual Active Bridge converter as a key interface between renewable energy and new energy vehicles has great practical application prospects and academic research value.The Dual Active Bridge converter is widely concerned by academia due to its advantages of symmetrical structure,zero-voltage switching capability,and flexible control methods.However,the disadvantages of high backflow power ratio,high current stress of the switch tube,and narrow soft switching range at light load make the dual active bridge limited in practical applications.This dissertation takes the dual active bridge as the research object,gives solutions to the above shortcomings,and optimizes the performance of the Dual Active Bridge.In order to solve the problem of high current stress of the switch tube of the dual active bridge converter and optimize the performance of the dual active bridge converter,a control strategy for minimizing the peak value of the inductor current based on triple phase shift control is designed in this dissertation.This strategy uses Lagrange multiplier method to minimize the peak value of the inductor current of the dual active bridge,and then divides the working interval according to the soft switching conditions.Under the premise of ensuring soft switching,this strategy optimizes the peak inductor current in the full gain range and improves the performance of the dual active bridge.In order to solve the problem of high proportion of backflow power of dual active bridge converters,a method for minimizing backflow power based on triple phase shift control is proposed.This method uses the Lagrangian multiplier method to minimize the backflow power of the dual active bridge,and then divides the working interval according to the soft switching conditions.This method optimizes the backflow power to 0 in the low and medium power range,minimizes the backflow power in the high power range(the minimum can be 0),and guarantees the zero voltage turn-on of the full active switch of the dual active bridge.In order to solve the problems of low efficiency and narrow soft switching range of the dual active bridge converter,a control strategy for minimizing the effective value of the inductor current based on triple phase shift control is proposed.Due to the complicated expression of the inductor current effective value,it cannot be optimized by the Lagrange multiplier method,so thedifferential perturbation method is used to solve the relationship between the three phase shift angles when the current effective value is the smallest,and then obtained by decoupling.This strategy ensures that the dual active bridge works under the premise of soft switching,optimizes the effective value of the inductor current,and improves the performance of the dual active bridge.