摘要：煤炭是我国国民工业生产和经济增长不能或缺的重要能源之一，我国的煤炭产出和消耗都位居世界前列。因为我国煤炭产量的几何上升以及当代科技的蓬勃发展，机械制造及其自动化水平持续改善，各种易燃易爆的场合中都普及了新型的高度集成智能化电气设备，不合规范的使用电气设备或者电路元件的老化问题都很容易引起短路且产生放电火花，引爆可燃气体混合物，对生产生活的影响非常严重并有可能造成重大损失。本安防爆技术是当今运用最为广泛的一种技术，本课题通过理解运用本安防爆技术，基于反激式变换器，研制了一款恒流型本安开关电源。

首先，本文由研究本质安全理论进行入手。通过了解研究爆炸要素和危险环境的分级等相关知识，引入本质安全理论的介绍。对电容性电路的放电形式和放电特性进行分析，得知电容短路时，会以电火花的形式进行多余能量的集中释放。所以要求设计电源时能够最大可能限制故障时产生的火花能量，使其不能满足点燃爆炸性混合气体的前提。然后通过参考煤矿下的环境情况，确定本安电源相比与其他电源必须拥有的功能或特殊要求，以此确定本安电路的设计架构与功能模块。

然后进行本安电源电路设计，包含主电路，开关控制电路，过压过流保护电路等的设计。结合本安要求和电气性能双指标优化变压器和滤波电容等，实现降低纹波。在控制电路中运用PWM控制芯片UC3842和双运算放大器LM358，以此实现输出过压和恒流控制。在保护电路中，为了加速故障保护，缩短火花放电时间，提高输出功率，采用电流变化率检测，驱动方式采用图腾柱式。

最后的任务就是搭建系统仿真平台，通过利用MATLAB仿真软件对数学表达式进行仿真，验证电容串联电阻有利于抑制电容短路时的放电能量。利用simulink建立电路仿真模型，联系实验结果验证理论方法和设计的有效性。

关键词：本安直流电源；开关电源；本质安全型；反激式；过压过流保护；

Abstract：Coal is one of the most important energy sources in Chinese national industrial production and economic growth. Chinese coal output and consumption are among the highest in the world. Because of the geometric rise of our country’s coal production,the vigorous development of contemporary technology as well as the continuous improvement of the level of machinery manufacturing and its automation, all kinds of flammable and explosive occasions are popular in the new highly integrated intelligent electrical equipment.Substandard use of electrical equipment or the aging of circuit components are prone to short-circuit,and it will produce spark discharge, then detonate combustible gas mixture.The impact of production and life due to it is very serious and may cause significant losses.Intrinsically safe and explosive technology is the most widely used technology.Through the understanding of the use of intrinsically safe explosion-proof technology,this subject,based on flyback converter, developes a constant current intrinsically safe switching power supply.

First of all, this paper starts from the study of  intrinsically  safe theory. Through the study of explosive elements,dangerous environment classification and other related knowledge, the intrinsic safety theory is introduced. The discharge mode and discharge characteristics of the capacitive circuit are analyzed to show that when the capacitor is short-circuited, the concentration of excess energy is released in the form of spark. So it requires that the design of the power supply can be the most likely to limit the generated energy to the spark, so that it can not meet the premise of igniting the explosive gas mixture. And then by reference to the the environmental conditions in coal mines , we can find that compared with other power supply,the intrinsically safe power supply must have the specific function or special requirements, in order to determine the safety of the circuit design and function modules.