Research On The Control Strategy Of Battery Energy Storage Staggered Parallel Buck Converter

With the rapid development of new energy generation technology,the storage of electric energy has become the focus of attention at home and abroad,and more energy storage technology has been applied to it.In the Direct Current microgrid,battery energy storage has become a popular energy storage method,the charging management of battery energy storage and the guarantee of wide voltage range operation of the battery have become research hotspots.The charging management of the energy storage battery is mainly achieved by the Buck DC-DC converter,and the staggered parallel Buck converter can be adapted to the energy storage system with its various advantages,which has a good engineering application prospect.This paper takes the battery energy storage system as the research background,and takes the staggered parallel buck converter as the research object,the physical mechanism of the converter is analyzed and the mathematical model is established.The control strategy of the converter is mainly studied.Firstly,the energy storage technology and the research status of buck converter are introduced in detail,and the topology and control mode of buck converter are classified and elaborated.Secondly,the working principle of the main circuit of the two-phase interleaved parallel Buck converter is introduced,and the ripple problem of the converter is analyzed.In different working modes,mathematical models are established by state-space averaging method and small-signal model method.A current sharing control scheme is proposed to solve the unbalanced current problem of the converter,and a double closed-loop PI controller is added.The controller parameters are designed by using the pole assignment method.Combined with the actual system,the double closed-loop PI control of the converter is analyzed.Thirdly,due to the shortcomings of traditional PI control,linear active disturbance rejection control technology（LADRC）is introduced in this paper.The principle and performance of LADRC are analyzed in detail,and a double closed-loop control strategy based on LADRC is proposed,the voltage on the energy storage side of the control converter is stable.And adopt the method of current inner loop controller to distribute and share the current to solve the problem of uneven current of the two-phase interleaved parallel Buck converter.Combined with the physical model,a second-order LADRC is designed for the current loop,and a first-order LADRC is designed for the voltage loop.The stability of the control strategy is verified by mathematical analysis.Finally,the simulation model of the control system of the battery energy storage staggered parallel buck converter is established,the simulation and comparison with PI control under different working conditions verifies the effectiveness of the controller designed in this paper.