Research On ZVS Control Strategy Of Dual Active Bridge Bidirectional DC/DC Converter For Full Power Range

In the bidirectional DC converter,the Dual Active Bridge Converter(DAB)has a symmetrical structure and flexible control strategy,and has received extensive attention in the development of the energy Internet.In this thesis,the DAB converter is combined with the working principle of the topology to analyze the working characteristics of power bidirectional transmission,and the control strategy of full zero-voltage switching under wide range working conditions is proposed,which can greatly improve the transmission efficiency of the converter,especially the efficiency in the low power section;In addition,it can reduce noise and improve working condition,providing an effective solution for further increasing the operating frequency by using wide bandgap devices.Finally,an experimental prototype which is designed to verify the control strategy was analyzed in the thesis.The main contents of this thesis are as follows:Firstly,several commonly used bidirectional DC/DC converters are summarized,then the advantages and disadvantages of three types of dual active bridge topologies,which are respectively voltage type,current type and resonance type,are analyzed in detail.Secondly,the control method of the voltage-type DAB converter is studied.The working mode and basic principle of the converter under single phase shift(SPS),extended phase shift(EPS)and triple phase shift(TPS)are analyzed in detail.The power transfer expressions under various control modes are presented,and the full zero-voltage switching operating conditions and working ranges under different control methods are analyzed accordingly.Then,the thesis proposes a full zero-voltage switching operation control strategy for different power ranges during power bidirectional transmission.This strategy enables zero-voltage soft-switching control of full-power range for all the devices based on triple phase shift control.At the same time,this strategy enables the converter to have a quasi-minimum reflow power at any given power.Therefore,the transmission efficiency of the converter and the reliability of the converter are improved under the full range of operating conditions.The simulation model is built in the PLECS software to verify the control strategy.In this thesis,the experimental prototype parameters are calculated theoretically,the hardware and software design of the DAB experimental prototype is given,and an experimental prototype is built.This thesis verifies the correctness of the theoretical analysis and the validity of the proposed control strategy.Finally,the work of this paper is summarized and the research direction is prospected.