Research On Stability Of Cascaded DC/DC Converters

With the development of power electronics devices,power electronics has become a key technology in the electric power transformation.Various demands are needed in different fields such as the spaceflight,satellite system,power transmission.Recent years many researches are focused on distributed power systems because of the high flexibility,reliability,control accuracy and good redundancy.The stability of cascaded DC/DC converters has become a key point of the research.The Stability of cascaded DC/DC converters problems are discussed in the article.Then a new control scheme is promoted in the MR16 lighting system.The stability problem of cascaded system is solved with the new scheme.In the beginning,the modeling methods and the stability criteria are analyzed.The small signal models are obtained for different topologies.Based on the models,the close loop impedance characteristics are analyzed.The effects of bandwidth and phase margin to the close loop impedance characteristics are discussed in detail.Then design methods of bandwidth and phase margin are promoted.Then the compatible problems in the MR 16 lighting systems are analyzed.Based the analysis,the peak current control scheme is promoted.The main work is focused on the design of the bandwidth.Reasonability is presented with the theoretical analysis.In the last part of the article,the experimental prototypes are built and tested.The experimental results verify the theoretical analysis.The promoted scheme solves the compatible problems in the MR16 lighting system.Meanwhile,the stability of the system is also ensured in the parallel conditions.The power factor is better with the new scheme.