Modulation Optimization Of Four-winding Dual Active Bridge DC/DC Converter

The dual active bridge DC / DC converter has become an isolated DC / DC converter commonly used in renewable energy generation and smart grids due to its simple topology,easy control,bidirectional power transmission,and easy implementation of soft switching.Therefore,the research on DAB converter has become a hot research direction in academic circles in recent years.Under the above background,this paper intends to propose an improved DAB converter and design an optimized control scheme to expand the soft switching range of the converter without ignoring the parasitic parameters of the power device and improving the working efficiency in the full power range.In order to achieve the above research goals,this paper first proposes an improved dual active bridge DC / DC converter topology with a four-winding structure by improving the traditional DAB topology,and the current and power characteristics of the topology under extended phase shift modulation and triple phase shift modulation are derived.Then its soft switching conditions are analyzed,a soft switching control scheme suitable for the full power range is proposed and verified by simulation.Then,the average current characteristics under EPS and TPS modulation are derived respectively,and detailed calculation methods of switching loss and conduction loss are given.Based on the analysis results,a hybrid phase shift modulation scheme is proposed to further optimize the converter's operating efficiency on the premise of implementing soft switching.Finally,a 1000 W experimental platform was set up,and the correctness of the theoretical analysis was verified by analyzing the steady-state waveform,soft-switching waveform and efficiency of the converter.