| In light of a growing shortage of fossil resources,the development of electric drivenvehicles has become an inevitable trend in recent years,subsequently facilitating advances in power batteries and other energy storage devices.The quality of power batteries is closely related to the process of battery formation,an indispensable process of manufacturing batteries.Currently,enterprises in China are impeded by the limited battery manufacturing technologies in domestic and the high costs of foreign equipment,which makes it necessary to design a new system to enhance battery formation.As one part of the “Transverse” research projects,this thesis designs a small-sized interleaved magnetic integrated bidirectional DC/DC converter of low ripple and high efficiency.Based on the feature of this converter,a new battery formation system is developed.The main research contents are as follows:(1)Researched and analyzed 2-channels interleaved magnetic integrated bidirectional DC/DC converter,and introduced essential technologies in battery formation.Firstly,the concept of formation is explained,and the characteristics of the battery,as well as its method of charging and discharging are introduced respectively.Secondly,the Boost and Buck working states of two channels DC/DC interleaved magnetic integrated bidirectional DC/DC converter are analyzed.The transient and steady-state inductors are anatomized in detail.Above analysis exhibits the advantages of the converter and the feasibility of applying it to the battery formation system.(2)Proposed an “EEEE” shaped coupling inductance.Considering the shortcomings of the traditional coupling inductance,an “EEEE” type coupling inductance is proposed to apply in two channels DC/DC interleaved magnetic integrated bidirectional DC/DC converter.The magnetic circuit model is deduced in detail,which proves to be correct by referencing the simulation results and the inductance prototype.Compared with the traditional “EI” type coupling inductance,this thesis claims that the advantages of “EEEE” shaped coupling inductance is evident.(3)Designed a double closed-loop PI controller of interleaved magnetic integrated bidirectional DC/DC converter.According to the working state of the converter in the state of boost and buck,the state equations are listed respectively.The control model of the system is obtained by using the method of state space averaging.Then,with a further addition of PI compensation,the stable system double closed loop Controller is obtained.(4)Designed and manufactured a battery formation prototype.The module hardware and software design of the prototype are discussed in detail and a prototype is designed and manufactured accordingly.The function of this prototype is verified by formation craft.Consisting of the upper computer software,centralized controller of the back-end and lower computer,the energy-saving bus structure,this battery formation prototype has greatly avoided energy wastes.With its characteristics of high efficiency,low ripple,fast dynamic response,high efficiency and precision,the power battery formation system studied in this paper is easy to expand,able to meet the needs the domestic battery production industry,and hence has a broad market prospects. |
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