| In the process of the practical applications in many electronic facilities, sometimes because the output parameters(for example voltage, current, power) of the only one DC power supply don't satisfy the demand or go fault. It could lead to the low efficiency and yet break down in entire system. Therefore, we usually adopt multi-module power supplies parallel connection in practice. The technique of parallel current-sharing is a tendency of the power electronics, and the middle or low multi-module power supplies combination can satisfy many different power load in use of changing the number of the modules, and then each module could support the lesser electrical stress. So the parallel current-sharing system of high power switch supply can keep the higher efficiency and the quicker dynamic response, can well satisfy the need of high-power supply on characteristic, capacity, weight, volume, efficiency and reliability.In this paper, a high power switch supply is designed using push-pull PWM DC/DC converter circuit and the current-sharing circuit is designed for parallel operation of mufti-module. The relative operation principle is analyzed and the circuit parameters are designed. At last, a prototype is developed to validate the results.Firstly, the theory of push-pull PWM DC/DC converter circuit is studied and the controller SG3525 is used for control circuit. Secondly, the maximum current automatic current-sharing method has also been discussed in detail in the paper. According to the features of the maximum current-sharing method, three loops control have been adopted and the small-signal analysis method has been utilized. The current-sharing controller UC3907 is adopted to design current-sharing circuit for power supply, it can realize parallel multi-module to compose power supply system much more huge than one module. Finally, experimental results of the prototype are presented in the paper and the results of paralleling operation for two-power supply are presented. |
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