Characterization And Equalization Control Of Three-Phase Staggered Parallel Dual Active Bridge Series Resonant Converter

The three-phase interleaved parallel dual active bridge series resonant converter has the advantages of electrical isolation,bi-directional flow of energy,high stand-alone power,high power density,small filter capacitance,etc.,and it can work at higher switching frequency and reduce the converter volume.It is widely used in wind power,photovoltaic,electric vehicles and other new energy fields.In this paper,a combination of theoretical derivation,simulation analysis and experimental verification is used to study the three-phase interleaved parallel dual active bridge series resonant type converter.This paper summarizes the current research status of bi-directional DC-DC circuits at home and abroad,comparatively analyzes the advantages and disadvantages of several typical bi-directional DC-DC topologies,and selects the three-phase interleaved shunt dual active bridge series resonant DC-DC converter as the research object.Firstly,the total harmonic distortion,power factor and output current ripple of the resonant voltage and input current of the multiphase series resonant circuit are analyzed,and the advantages of the three-phase interleaved shunt dual active bridge series resonant converter are given and its working principle is analyzed.Based on the frequency domain analysis results of the three-phase interleaved parallel dual active bridge series resonant converter,the voltage gain,quality factor and other related parameters of the converter are designed.A small-signal model of the converter based on reduced order is derived,which lays the foundation for the design of the closed-loop control of the converter.The voltage closed-loop control is designed so that the output voltage dynamic characteristics of the three-phase staggered parallel dual active bridge series resonant converter are significantly improved.Due to the differences in the resonant parameters of each phase of the resonant converter,the current imbalance of each phase is caused.In this paper,a three-phase interleaved parallel dual active bridge series resonant converter with the primary and secondary edges of the transformer connected in a star pattern is taken as the object of study,and the influence of each resonant parameter on the current equalization degree of the resonant circuit is analyzed in detail,and an equalization control strategy based on the trigonometric method is investigated,which utilizes the cosine theorem to solve the phase relationship of the resonant currents,and then the phase of the currents is controlled by controlling the phase of the drive signal of the switching tubes to realize the current equalization,and the theory is verified by simulation.equalization,and verify the feasibility of the theoretical analysis through simulation.Finally,this paper selects the components of the converter,completes the design of the transformer,inductor and other magnetic components in the three-phase staggered parallel dual active bridge series resonant converter,and builds a 500 W experimental prototype to verify the validity of the above theoretical analysis.