Abstract: In this paper,first,an optimal control mode is selected from three control modes for synchronous rectification through energy consumption calculation,and the current sharing problem of the multi-tube paralleling in high-power synchronous rectification is investigated to overcome the output power limitation of single device and single circuit.Then,the main sensitive parameters affecting the parallel current sharing are determined,and a solution to the optimization of current sharing is presented.Moreover,the generation mechanism of the circulation caused by multi-circuit parallel connection is discussed,and a coordination control method of the duty cycle for preventing the circulation is finally presented.Experimental results show that the theoretical analysis is correct and that the proposed method helps to successfully implement the high-power output of synchronous rectification.

Key words: high-power synchronous rectification, control mode, multi-tube paralleling, multi-circuit paralleling