Optimum Design Of Multiplexed Bidirectional DC/DC Converter Of Energy Storage In DC Microgrid

Because of the lack of clean energy and low utilization rate of traditional energy,people pay attention to the development of new energy sources,and the utilization of energy has become a hot issue in twenty-first Century.With the rapid development of new energy sources,microgrid technology has been developed unprecedentedly.As an important part of microgrid,energy storage system has attracted more and more scientists' attention and research.With the bi-directional DC/DC Converter(BDC)as a key part of the storage system,it plays an important role in the utilization of new energy.Limited by the device technology,a single bi-directional DC/DC converter has been difficult to meet the needs of high power devices,so the multiple staggered parallel bi-directional DC/DC converter become a research hotspot.The research of multiplexed bidirectional DC/DC converter is of great significance to the improvement of converter power and the optimization of power quality.In this paper,the multiple BDC is used as the analysis object.Firstly,the topology of the four basic BDCs is analyzed,and the multiple BDC is constructed based on the half bridge BDC.The working principle of the half bridge BDC is analyzed.And the small-signal model is established by using the state space averaging method.Secondly,the current ripple of inductance and capacitance of multiplex BDC is analyzed.Based on the MATLAB platform,the multiplicity of the multiplex BDC is optimized by genetic algorithm.Then,according to the average state space model of the bidirectional DC/DC converter,the compound correction of the current and voltage double closed loop control strategy is proposed by means of variable substitution and parameter estimation.According to the standard two order system,the calculation formulas of the parameters are obtained,and the disturbance rejection characteristics of the voltage outer loop are analyzed,which provides a basis for parameter selection.And the circulation problem is analyzed and solved by using the digital current sharing method.Finally,the weight of single BDC and multi BDC model was established by using matlab/simulink,in accordance with the technical indicators completed the design of capacitance and inductance,and completed the design and experiment of single bidirectional DC/DC converter.