The Synthesis Methodology And Performance Analysis Of Integrated Multi-port DC/DC Converters

Power electronic converters gain more and more attention in the distributed energy system,especially multi-port DC/DC converter which can realize the multi-connection of source,energy storage element and load.In addition,multi-port DC/DC converters are generally required in the vehicles electrics,stand-by power supplies,bias supplies,LED drivers,multilevel inverters and communication system,etc.The employment of the existing multi-port DC/DC converter is limited due to the large device number,poor cross regulation and low efficiency.A comprehensive review of the existing multi-port DC/DC converter is summarized,based on which a novel synthesis methodology of multiplex-switch multi-port DC/DC converter is proposed in the paper.The conventional separate bidirectional multi-port converters require 2N switches to generate N outputs,and the conventional unidirectional N-outputs converters require N switches and N diodes.But theoretically,N outputs are determined by N control variables and thus only N+1 switches are needed.In this paper,a family of multiplex-switch multi-port DC/DC converters is derived from the proposed synthesis methodology which can obtain N independent ports with only N+1 switches.Both isolated and non-isolated modules are extracted from the conventional basic isolated and non-isolated DC/DC converters in this paper.And the proposed synthesis method integrates the modules with conventional DC/DC converters.A family of non-isolated multi-port DC/DC converters can be derived by integrating non-isolated converters with non-isolated modules.Similarly,a family of isolated multi-port DC/DC converters can be obtained by integrating isolated converters with isolated modules.Besides,a family of mixed multi-port DC/DC converters also can be derived.There are two different connection manners of the modules in the integrated multi-port DC/DC converters,and they can be combined in one converter.The proposed converter can satisfy different requirements with appropriate connection in various applications.Then the integrated dual-output buck converter is analyzed as an example of non-isolated mul-port DC/DC converter.The proposed integrated buck converter is composed of a conventional synchronous buck converter and a buck module.The two outputs can be controlled independently by three switches.The switch count is reduced in this converter,and zero-voltage-switching(ZVS)operation is retained for one switch which reduces the switching loss.Besides,the equivalent mode of the circuit is derived,which is basis of close-loop control.The design method of the integrated dual-output buck converter is given in this paper,based on which a prototype is built to verify the theories.In order to reduce the volume and component number,magnetic coupling which integrates two inductors into one magnetic core is applied in this converter.The design method of parameters and control loop is discussed.Finally,a prototype is built to validate the correctness and feasibility of the theories.The integrated dual-output flyback converter is analyzed as an example of isolated mul-port DC/DC converter.The proposed integrated flyback converter is composed of a conventional asymmetric flyback converter and an asymmetric flyback module.Three switches are soft-switching which reduces the loss.In the meanwhile,the integrated dual-output buck-flyback converter is analyzed as an example of mixed mul-port DC/DC converter.The proposed integrated buck-flyback converter is composed of a conventional synchronous buck converter and an asymmetric flyback module.The theories and experiment results of the integrated dual-output flyback converter and the integrated dual-output buck-flyback converter are given to validate the topology synthesis methodology.