Characteristic Analysis And Loss Model Of Series Resonant Three-phase Dual Active Bridge Converter

The three-phase dual active bridge(Dual Active Bridge,DAB)converter has the advantages of bidirectional energy flow,high reliability,and high power density;and compared with the single-phase DAB converter,the input and output current ripple is smaller,The voltage and current stress of the switching device is smaller,so it has higher reliability.Studying the operating characteristics of a three-phase DAB converter and guiding the circuit optimization by analyzing its loss model is of great significance for improving the utilization rate of new energy.In this work first introduces the application background and research significance of the three-phase dual active bridge converter,and outlines the research status and basic control methods of this type of topology.Among them,the series resonant three-phase dual active bridge converter,because the circuit structure is simple and the forward and reverse symmetry,has a resonant current similar to a sine wave,and can exhibit higher circuit efficiency than the non-resonant DAB converter,so this article Research object.Secondly,the effects of three-phase transformers on the main circuit operating characteristics under the three connection modes of star-star,angle-angle and star-angle are analyzed,and the current and power expressions and soft switching conditions under various connections are deduced in detail.;And compared the active power,soft switching range,and current stress of the switching device of the series resonance three-phase DAB under the three connection modes of the transformer.Then,specifically for the star-angle connection circuit topology,the working mode of the converter is analyzed in detail,and the converter model is greatly simplified by converting the transformer secondary circuit to the primary side.On this basis The influence of resonance parameters on the converter is analyzed,and the hardware parameters of the series resonant three-phase converter are designed.In this work also introduces phase shift + asymmetric duty cycle modulation,and compares this modulation method with single phase shift modulation.The effective value of the primary current of the transformer,through comparison,finds the phase shift + asymmetric duty cycle A combination of duty cycle and phase shift angle that minimizes the effective value of the primary current of the transformer under modulation.In this work also models and simulates the losses of magnetic components such as transformers and inductors of series resonant three-phase converters,analyzes the on-statelosses and switching losses of the switch tubes,and establishes the losses of series resonant three-phase DAB converters model.Finally,a 500 W experimental prototype was designed to verify the accuracy of the above theoretical analysis and loss model.