Dual-protection circuit for mine intrinsically safe power supply

Abstract

The invention discloses a dual-protection circuit for a mine intrinsically safe power supply. The dual-protection circuit for the mine intrinsically safe power supply comprises a first-level protection circuit and a second-level protection circuit. The input end of the first-level protection circuit is connected to the output ends of sampling circuits and the output end of the first-level protection circuit is connected to a first switch. The positive electrode of an input power supply and the positive electrode of the intrinsically safe output are connected through the first switch. The input end of the second-level protection circuit is connected to the output ends of the sampling circuits and the output end of the second-level protection circuit is connected to a second switch. The negative electrode of the intrinsically safe output and the negative electrode of the input power supply are connected through the second switch. The sampling circuits comprise a current sampling circuit and a voltage sampling circuit. The dual-protection circuit for the mine intrinsically safe power supply can cut off output in the case of overcurrent or overvoltage and is simple in structure, low in cost and capable of reaching the turn-off speed up to 1 us and automatically returning to work after the fault is removed.

Description

technical field [0001] The invention relates to the field of intrinsically safe power supplies, in particular to a dual protection circuit for mine intrinsically safe power supplies. Background technique [0002] In the explosive gas environment of coal mine or petrochemical industry, such as in the environment with explosive mixtures such as methane, gasoline, coal dust, etc., the use of electrical equipment has strict requirements on the voltage and current of the power supply. The normal operation of electrical equipment is of great significance to the safety of underground coal mines. It is directly related to the safe operation of underground coal mines. All electrical equipment must work within the allowable voltage and current range. [0003] The core of the intrinsically safe power supply for mining is the protection circuit. According to relevant standards, the intrinsically safe power supply for mining needs to have dual over-current and over-voltage protection cir...

AI Technical Summary

Problems solved by technology

[0004] The patent "Secondary Protection Circuit for Mining Power Supply Safety" with the application number "CN201110375240.6" can provide protection in the event of over-current and over-voltage, but it only shuts off the positive pole of the intrinsically safe output and does not shut off the intrinsically safe output Once the switch is out of control, it loses its protection function and has low safety performance.

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