Research On Flyback Equalization System Based On Concentric Multi-windings

The power lithium battery is affected by various factors to varying degrees,resulting in different degrees of inconsistency between its own parameters between the monomers.Using equalization technology to control the degree of difference in the working status of the monomer within an acceptable range ensures that the series battery pack use an effective way to work safely and reliably.The ideal equilibrium topology should be reliable,stable,efficient,and easy to control.At present,there are many balanced topologies.However,it is difficult to achieve both balanced speed and balanced efficiency.Therefore,designing a high-performance balanced topology and control strategy becomes the current research on equalization technology hot spots.In this paper,a flyback-type balanced topology based on multi-winding of the same core is constructed.Through the principle analysis and simulation verification of the circuit,it is shown that the topology can achieve direct equalization between any of the cells.In order to deeply analyze the influencing factors of equalization circuit equalization performance,an equivalent circuit model under two different operating modes is established.The influence of parameters such as equivalent resistance,switching frequency,and duty cycle on the equalization efficiency and the equalization speed in an equalized topology is established.Theoretical derivation were performed,and the influence of various parameters on the equilibrium efficiency and equilibrium speed was summarized,which provided theoretical support for the optimization design of balanced topology.By analyzing the causes of battery imbalance and related manifestations,the advantages and disadvantages of current commonly used equilibrium strategy variables are summarized;with the goal of maximizing the available remaining capacity,an optimization control model of the equilibrium process is established,and the solution model is obtained based on the maximum remaining available energy.The balance control parameters,through the relevant theoretical analysis and simulation,verify the effectiveness of the algorithm in improving battery utilization efficiency.The equalizer driver circuit is optimized to improve the equalization speed and efficiency,and the battery management information chip LTC6803 is used to collect information.A six-cell direct equalization system was set up and two different working modes of the equalizer were experimentally verified.Based on the analysis of the influence of various parameters on the equalization performance,a parameter verification experiment was conducted to prove the correctness of the theoretical analysis;Under working conditions,static experiments,charging experiments,and discharge experiments were performed,respectively,and the equilibrium functions of the equalization system under different working conditions were verified.