Modeling And Control Of DBSRC Converter Based On ISOP

This paper studies the bidirectional DC-DC converter which can be used in V2 G charging pile.An input series output parallel(ISOP)type double-bridge series resonant converter(DBSRC)is studied considering that the electric vehicle charging post has to operate under the conditions of high power,high efficiency and wide output voltage variation range.First,a first-order generalized averaged small signal model of DBSRC is constructed.The method of analyzing the steady-state characteristics of the converter using the active and reactive components of the generalized average model allows the calculation of the expressions for each steady-state quantity in the converter.On this basis,the range of full-bridge soft-switching with different gain is analyzed,and the change trend of resonant current peak on the active curve is also analyzed,which provides theoretical support for the design of the following control scheme.Apply the modeling results of a single DBSRC converter to ISOP-DBSRC and derive the transfer function matrix of the ISOP-type DBSRC converter.Secondly,A dual-loop decoupling control scheme is used to decouple the modules,and then a dual-loop control scheme containing an input voltage equalization loop and an output voltage loop is designed to achieve power balancing between the modules.By using the Lagrange multiplier method,the phase shift angle combination that can minimize the peak value of the resonant current is selected in the soft switching range,and an optimal control scheme to reduce the peak value of the resonant current is proposed.Combined with the above dual-loop decoupling control scheme,a hybrid optimal control strategy is finally proposed.Then,design of parameters for converters with wide gain range.The soft-switching in wide gain range is analyzed,and the maximum range of gain variation in soft-switching range is calculated.Combined with the required gain range of the converter,the range of transformer ratio and gain coefficient satisfying the design conditions is determined.The values of transformer ratio and gain coefficient are determined by comprehensive consideration,and the theoretical values of resonant inductor and resonant capacitor are calculated.Finally,the effectiveness of the hybrid optimal control strategy proposed and the practicability of parameter design in this paper are verified by PSIM simulation software and an 800 W experimental prototype.