The Design Of Flame-proof&Intrinsically Uninterruptible Power Supply In Coal Mines

Due to the rapid development of modern science and technology,there is a growing numbers of coal,which will inevitably lead to the high integration of the new intelligent electrical equipment widely applied to such as coal mine inflammable and explosive situation, these electronic equipments need to be powered by underground power supply, power supply as the "heart" of the electrical equipment, it’s intrinsic safety play a crucial role to the whole circuit.This paper will use the mature switching power supply technology applied to the study of intrinsically safe circuits, and develop a intrinsically safe DC power output with21V/300mA. The power supply has the advantage of small volume, low cost, input and output with electrical isolation, it can realize multiple intrinsically safe output, it also can provide different voltage operating voltage for various electrical devices which work in dangerous environment.When the capacitor short-circuit,the spark will appears.It release the redundant energy,so in design the intrinsically safe power supply we should be strictly controlled the spark energy when there is a fault,makes it don’t have the condition of ignited combustible gas mixture.The rectification filter circuit of input stored large energy in the entire power system.This paper will set out to explore this part of the circuit, threaded a resistor on the input filter capacitor to reduce the capacitance transient discharge current of short circuit, thereby to limit the spark discharge energy and increase its intrinsic safety characteristics.The Analysis of discharge Characteristic of capacitive intrinsic safety type circuit provides a favorable theoretical support for intrinsically safe power supply. For the design of the intrinsically safe circuit,it’s effective to reduce the discharge sparks.But appear unknown circuit fault lead to spark produce is inevitable,it is necessary to design a explosion-proof shell for power supply,adds a security for power supply.The next task is to carry on the intrinsically safe Explosion-proof DC power with system research,this paper analyzes the circuit design, the basic principle and method of calculation and determine the technical parameters of the intrinsically safe circuit.This paper discusses the intrinsically safe circuit and the immaterial safety circuit and anti-jamming measures of processing.Then complete draw the schematic diagram of the Design of Flame-proof&intrinsically Un-interruptible Power Supply in underground coal mines、and PCB design、the important components of the selection, welding, circuit commissioning work,and then completed to test the output of intrinsically safe power supply.According to the experimental data shows that the project design of intrinsically safe uninterrupted power supply of the main circuit and overcurrent-overvoltage circuit working properly, the power’s output is stable and the ripple voltage is small, can achieve the basic requirement of design.