Research On Optical Storage Three-port DC Converter Based On GaN Device

With the increasing global energy crisis and environmental pollution problems,the distributed power generation technology of photovoltaic and energy storage has received extensive attention and research from domestic and foreign scholars.Compared with the traditional multi-level converter,the three-port optical storage converter realizes topology reconstruction through power device sharing,which improves the power density of the system.Based on the dual active bridge converter,this paper designs an integrated three-port DC/DC converter with interleaved parallel bidirectional Buck/Boost circuit in the front stage and dual active full bridge circuit in the back stage.It has the characteristics of flexible buck-boost and bidirectional power flow of dual active bridge circuits with interleaved parallel bidirectional Buck/Boost circuits,simple structure,and suitable for various photovoltaic energy storage microgrid systems.First of all,through the analysis of the main part of three port converter dual active bridge circuit control mode,working mode and detailed analysis of the steady-state operating characteristics,using multi-objective particle swarm optimization(pso)algorithm,the reflux power and inductance current RMS as the optimization goal,compared to move as optimization variables,get the best move in combination,established the dual active bridge circuit of small signal model and design the MOPSO controller,to control of converter,reduces inductance current RMS system with reflux power,improve the efficiency of converter.The small signal model of lifting voltage circuit is established for the front stagger parallel bidirectional Buck/Boost circuit,and the PI controller parameters are designed based on the model.Combined with the shift-phase control of back-stage DAB,the duty ratio control method is adopted to expand the range of input voltage of DAB,ensure the stability of input voltage of back-stage circuit,improve the freedom degree of system control,and realize the three-port power flow function.Finally,the integrated three port converter in duty ratio and phase shifting control strategy under the steady working mode and power transfer characteristic has carried on the thorough analysis,built in the Matlab simulation model,validation of two-stage type three port system design feasibility and accuracy of control method,and based on the third generation of wide bandgap semiconductor gallium nitride devices to build system prototype,and through the hardware-in-the-loop simulation platform d SPACE combined with prototype,through hardware in loop simulation verified the feasibility and effectiveness of the new three port converter system.