Research On Topology And Control Of Multi-phase Interleaved Bidirectional DC/DC Converter With Coupled Inductors

With the rapid development of new energy and modern power grid,interleaved bidirectional DC/DC converters(IBDC)play an increasingly important role in electrical field and are widely used in fuel cells,hybrid vehicles,photovoltaics and wind power generation.In order to simultaneously improve the steady-state and transient-state performances of the converter and reduce the volume of magnetic components,magnetic integration and reverse coupling technique are introduced in IBDC.Therefore,the research on multi-phase IBDC with coupled inductor(CI)is of great significance.With the number of phases increasing,however,this may suffer several issues,such as asymmetry of magnetic components,difficulties of designing suitable multi-phase magnetic core,large DC flux and so on.To solve these issues,a multi-phase IBDC with two-winding coupled inductors is proposed and analyzed.Two four-phase IBDC are taken as an example in this paper,where four CIs are used to replace the single-core coupled inductor.The steady-state and transient-state performances of the proposed converter are studied in detail.The advantages of the two topologies are compared.The superiority and practicability of the proposed converter are first verified by the theoretical analysis.In order to reduce the switching loss of the switches and improve the efficiency of the converter,soft-switching technology is applied to the proposed converter.Without changing the any hardware of the proposed converter,ZVS can be achieved by reasonably controlling the value of peak phase-current and the dead-time.The realization conditions of ZVS are then analyzed in more detail.Due to the difference of the parasitic parameters among phases,the proposed converter may also suffer the issue of current unbalance among phases,which might deteriorate the converter reliability.Therefore,a current sharing control strategy based on phase current decoupling technique is proposed to solve this issue.The voltage and current dual-closed-loop control,as well as PI regulators parameters,are then designed and given.The correctness of the theoretical analysis and control strategy about the proposed converter is initially verified by PSIM and MATLAB Simulations.An experimental prototype of four-phase IBDC with coupled inductors is then built,which is controlled by TI DSP28335,and the corresponding hardware design and DSP software programming are thereafter performed.The superiority and practicability of the proposed converter,soft-switching performance and current sharing control strategy are finally verified by the prototype experiments.