Development Of 3kW Energy Storage Converter Based On Bidirectional CLLLC Resonance

In order to promote the development of new energy and reduce the pollution caused by traditional fossil energy to the environment,two-way DC/DC converter,as a key link of energy conversion,has been actively promoted in the fields of distributed energy,uninterruptible power system and new energy storage system.The bidirectional DC converter has the advantages of low voltage stress,high power conversion efficiency and high power transmission.In this paper,the bidirectional CLLLC resonant converter is deeply studied.Through the analysis of its circuit structure and operation principle,the digital control technology is adopted to further improve the efficiency and accuracy of the converter,which will play a positive role in promoting the development and application of bidirectional DC converter in the field of new energy.Firstly,in this paper,the working principle of the bidirectional CLLLC resonant converter is analyzed,and then the equivalent model of the converter is constructed by using the fundamental wave approximation method,so as to facilitate the gain analysis of the converter.According to the reasonable selection of quality factor Q and inductance coefficient K,the resonant parameters of the converter are designed.Secondly,in order to make the resonant converter run stably,small signal modeling is carried out on the converter,on the basis of which the PI controller is designed,and the positive and negative closed-loop simulation verification is carried out,and the reversing control strategy based on the current and voltage judgment is proposed.Finally,the hardware system parameters of the converter are designed,the main circuit components of the converter are selected according to the requirements,and the loss analysis is carried out.On the basis of the above,a 3k W experimental platform is built to complete the positive and negative experimental verification.The experimental simulation is consistent with the theoretical results,which proves the correctness of the theoretical analysis.