可调电流比例开关电源模块并联供电系统

A switching power supply module parallel power supply system with adjustable current ratios

为了满足大功率负载的供电需求,电源系统往往需要多个开关电源模块并联。由于不同电源模块之间的外特性有差异,直接并联不能保证供电系统正常工作,需要按各模块的输出能力分担电流。为此,采用主从设置法设计一款开关电源模块并联供电系统。设计主要部分是两个DC-DC开关稳压电源模块和电流测控系统。其中,开关电源模块的核心器件为LM2596调节器;集成运算放大器LM358用于电流信号的放大;电压比较器LM393用于比较主模块和从模块的电流值,并将比较结果返回从模块,从而起到控制两路电流比例的作用。当系统的总电流超过设定值时,启动过流保护功能。经过测试,该设计能够很好地实现两路电流比为2∶1,1∶1及其他比例的分配,电流相对误差小于2%,效率达到70%以上。

Multiple switch power supply modules need to be connected in parallel in the power supply system to meet the power supply demand of high-power load. As there exist differences between the external characteristics of different power supply modules,a direct parallel connection cannot guarantee the normal work of the power supply system,and the current should be distributed according to output capability of each module. Therefore,a power supply system with parallel connection of switching power supply modules is designed by using the master-slave setting method. The main part of the design is composed of two DCDC switching stabilized voltage power supply modules and the current measurement and control system. The core device of the switching power supply module is LM2596 regulator. The integrated operational amplifier LM358 is used to amplify the current signal. The voltage comparator LM393 is used to compare the current values of the master module and slave module and return the comparison results to the slave module,so as to control the ratios of two currents. When the total current of the system is higher than the set value,the over-current protection function is enabled. The test results show that the design can realize the distribution of 2∶1,1∶1 and other ratios of two currents,with relative errors of currents lower than 2% and efficiencies over70%.