(整理)开关电源模块并联供电系统3

赛题号：A 参赛队号：20110092

开关电源模块并联供电系统

摘要: 在电源的实际使用过程中，各种负载对于供电的可靠性要求不同，当单台电源不能提供负载的全部容量的时，就需要多个电源模块并联使用，以提高电源的容量和运行的可靠性。

在实际的使用过程并不是简单的把各个电源并联使用就可以让电源平均承担功率。这是由于电源各自参数的分散性，使得每个电源的开路电压和内阻均会存在差异，通常开关电源的内阻都非常小，因此开路电压很小的差异就会导致各电源的输出电流有较大的差异，这种状态会导致各个电源的寿命衰减不一致，达不到电源的可靠性和稳定性的要求，这就要求在电源并联使用过程中使用均流技术。

对设计工程师来说，环流会造成毁灭性灾难，无论你的设备是计算机还是通信系统。有些工程师缺乏对环流的正确认识，因为在原理图上一般用一个接地符号或公共符号表示所有电路的返回路径。初级工程师经常错误理解这个符号，认为它代表零阻抗。情况并非如此，接地符号只表示你原理图上的一种线路。如果接地连接中的电流足够大，或者变化得足够快，就会产生一个相当大的电压，该电压可能影响到电源的精度。另外，在仪表应用中，该电压还会造成测量误差，数字系统工程师必须努力应对接地弹跳问题。音频缓冲器会出现可怕的接地环路中的环流效应，它会引起蜂鸣和哼声。

关键词：BUCK DC-DC变换 LM2576 LM331 PWM调压

Abstract: In the power of the actual use of the process, various load for power supply reliability requirements are different, when a single power supply can not provide the full load capacity, we need more power modules in parallel, in order to improve the power supply capacity and reliability.

In actual using process it is not simple to various power supply in parallel using can make the power to bear an average power. This is due to the power source to the respective parameters of the dispersion, such that each power supply voltage and internal resistance will exist differences, usually switch power source internal resistance is very small, so the open-circuit voltage is a very small difference will lead to the power of the output current has bigger difference, this condition leads to various power lifetime decay inconsistent, amounted to the power supply reliability and stability requirements, this requires that the power supply in parallel using a process using current technology.

For design engineers, circulation can cause catastrophic, whether you device is a computer or communication systems. Some engineers lack correct understanding of

circulation, as in the diagram with a grounding symbols or public symbols representing all circuit return path. Junior engineer often wrong understanding of this symbol, it represents a zero impedance. That is not the case, an earth symbol just means you diagram on a line. If the ground connection of current is large enough, or the change fast enough, will produce a large voltage, the voltage may affect the power of the precision. In addition, the instrumentation applications, the voltage will result in measurement error, digital systems engineer must try to cope with the problem of ground bounce. Audio buffer will be terrible in the ground loop circulation effect, it would cause a buzz and hum.

KEY WORD:：BUCK DC-DCtransform LM2576 LM331 PWM booster

引言

1）任务

设计并制作一个由两个额定输出功率均为 16W 的 8V DC/DC 模块构成的并联供电系统（见图 1）。

2）要求

1.基本要求

（1）调整负载电阻至额定输出功率工作状态，供电系统的直流输出电压U O=8.0±0.4V。

（2）额定输出功率工作状态下，供电系统的效率不低于 60%。

（3）调整负载电阻，保持输出电压U O=8.0±0.4V，使两个模块输出电流之

和I O =1.0A且按I1:I2=1:1模式自动分配电流，每个模块的输出电流的相