The Study Of Digital Soft Switching Bidirectional DC/DC

With the development of technology in recent years,the Bidirectional DC/DC converter has been widely used in the field of renewable energy generation system,electric vehicle energy management system,aerospace electrical power system,DC unremitting power source system and received extensive attention.The isolated bidirectional full-bridge DC/DC converter has a symmetrical topology structure,so through the corresponding control we can achieve bidirectional energy transfer and zero voltage switching,so build a bridge of energy exchange between the storage unit and the DC bus.This paper mainly focuses on the control algorithm to improve the steady state performance of the converter.In this paper,beside the topology of the bidirectional full-bridge isolated DC/DC converter,the traditional phase-shift control,dual phase-shift control and triple phase-shift control has been further studied.The working process of the bidirectional DC/DC converter under different control strategies has been analyzed and the corresponding mathematical model is established.Based on the mathematical model,analyzed the characteristics of three kinds of phase-shifting control systems,such as transmission power,backflow power,current stress and soft switching range.Clearly the traditional phase-shift control system of power transmission has minimum flexibility and backflow power can not be eliminated.The dual phase-shift and tripe-phase shift control technology is able to reduce the backflow power of the system on the basis of increasing the flexibility of transmission power,and the tripe phase-shifr control technology can reduce the current stress.According to the influence of the backflow power to the system,the optimal control strategy of the minimum backflow power in the soft switching range is proposed on the basis of the double phase-shift and the tirpe phase-shift control.The simulation results of three control algorithms and the optimal control strategy of minimum backflow power are verified by Matlab/Simulink platform.Finally,the hardware and software are designed,and the experimental platform of bidirectional DC/DC converter system is built.TMS320F28335 is selected as the digital control chip of the whole system.The correctness of the algorithm and the rationality of the hardware and software design are verified by the experimental results.The experimental results coincide with the theoretical analysis.