Study On The Stability Of Battery Formation System With Energy Feedback Function

With the rapid development of battery formation system, modular and high performances have been become an inevitable trend. In this design, the structure adopts two-level DC/DC converter cascade through the DC bus, so the system stability need to be analyzed in the case of energy two-way flow with the battery charging and discharging number changes, that is, achieve stability analysis with energy feedback systems function.Firstly, according to the working principle of three level half bridge current doubler DC/DC converter and non-isolated DC/DC converter with coupled inductor, the paper study the small signal modeling and related closed-loop design along with energy two-way flow, at the same time, the paper has got the closed-loop transfer functions.Furthermore, this paper studies the closed loop impedance characteristics of three level half bridge current doubler DC/DC converter and non-isolated DC/DC converter with coupled inductor in the condition of two-way flow of energy. Under this analysis, the factors affecting the closed loop impedance have been analysised, summed up corresponding rules to lay the foundation for the next cascade design guidelines designed.In the analysis of the stability of low voltage DC bus, the system is divided into two cases according to the direction of energy flow three level half bridge current doubler DC/DC converter, and in each case it has been analysised the largest battery charging and discharging number on the DC bus. Then analyze improve way under the conditions of two-stage DC/DC fixed parameter, get the conclusion of the improve stability effect of increasing capacitance filter at the DC bus side.Finally, utilising the network analyzer to achieve the associated impedance test, combined with matlab/simulink to simulation to verify the correctness of the related conclusion.