| DPS (distributed power system) has been applied more and more widely because of large-power application requirements. And multi-module paralleled power supply is in more common use. But current-sharing control must be introduced in the paralleled system to balance power distribution, because every power module has various electric characteristic. Current-sharing technique is one of key techniques in the paralleled system.There are many Current-sharing methods at present. Automatic current-sharing technique and droop method is widely in use in the numerous methods. Firstly, DPS and several current-sharing methods usually used are simply introduced. Secondly, the theory of these two methods is differently analyzed in detail. The result is validated through simulation in the end.The droop current-sharing method has many practical realizing modes. The principles of three methods are analyzed in detail, based on complexity, cost, modularity, reliability, and current-sharing performance etc. The three methods' small signal models are listed. A detailed comparison between these methods through the simulation of two Buck low power level modules paralleled. Drawing a conclusion that active droop method has good current-sharing effect.Automatic current-sharing technique is widely in use in the numerous methods for its high control precision and easy realization. At the same time, the method's current-sharing purpose is not good and a big range surge will come forth in its current in dynamic procession. In order to improve the transient response of current sharing, this paper develops an improved automatic current-sharing technique with average-current mode control. The control system has three control loops. The paper advances the design principle for current loop voltage loop and current-sharing loop. Set up the theory foundation for the paralleled system. Finally, a prototype with two Buck modules is set up and emulation data verify the performance of current sharing.
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