Small size 4-way output mine intrinsic safety power supply

Abstract

This utility model relates to the field of mining power supply technology, and in particular to a small-sized, four-output intrinsically safe mining power supply. It includes a flame-retardant protective shell, a circuit board, a base plate, injection holes, wiring studs, anti-loosening wiring nuts, hexagonal nuts, a first through hole, a second through hole, a third through hole, and a fourth through hole. The circuit board includes an input protection circuit and four DC / DC conversion circuits. This utility model is small in size, requiring neither an explosion-proof shell nor adhesive sealing, facilitating installation and maintenance, and meeting the lightweight requirements of underground equipment. An input protection circuit at the DC input terminal provides both reverse polarity protection and suppression of instantaneous current surges during startup, offering dual protection. It can simultaneously power different intrinsically safe devices, simplifying the layout of underground power supply systems, and can perform efficient and safe voltage conversion.

Description

Technical Field

[0001] This utility model relates to the field of mining power supply technology, and in particular to a small-sized, four-output intrinsically safe mining power supply. Background Technology

[0002] In the underground coal mine environment, safe production is one of the most critical challenges. Because of the mixture of coal dust and flammable and explosive gases such as methane and carbon monoxide, even a tiny electrical spark or high temperature can trigger a serious explosion, threatening the lives of miners and mine facilities. Therefore, electrical equipment in mines, especially the power supplies for monitoring, communication, instrumentation, and automation systems, must meet stringent explosion-proof requirements to ensure safe and reliable operation even in extreme environments.

[0003] Traditional explosion-proof power supplies typically employ flameproof enclosures or increased safety designs, preventing internal explosions from spreading to the external environment through physical isolation or enhanced structural strength. However, these methods have limitations such as large size, heavy weight, and complex maintenance, making it difficult to meet the requirements of lightweight and high reliability for downhole equipment. In contrast, intrinsically safe explosion-proof technology limits energy at the circuit design level, ensuring that electrical sparks or thermal effects generated by the equipment during normal operation and under any protective conditions are insufficient to ignite surrounding explosive gases, thereby fundamentally eliminating the risk of explosion.

[0004] Among the existing designs of intrinsically safe explosion-proof power supplies for mining, patent CN218888397U discloses an explosion-proof and intrinsically safe DC regulated power supply for coal mines. It obtains a stable DC voltage through a DC / DC isolation module, and then provides an intrinsically safe power output after passing through a voltage and overcurrent protection circuit. It has high reliability, but the power supply is equipped with an explosion-proof enclosure. Patent CN212435575U discloses an intrinsically safe solenoid valve power supply protection device. It protects the power supply by weakening the voltage surge generated when the intrinsically safe solenoid valve coil is working. It has high safety, but the improvement is limited to intrinsically safe solenoid valves. Patent CN207652332U discloses an intrinsically safe power supply, which makes improvements to power and soft-start function, but does not involve corresponding optimizations to the power supply equipment.

[0005] Based on existing technologies, in order to improve the reliability and portability of power supply equipment in the underground working environment of coal mines, it is necessary to design an intrinsically safe power supply for mining that does not require the installation of an explosion-proof enclosure, and can achieve lightweight and convenient installation and maintenance while realizing intrinsically safe output. Utility Model Content

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a small-sized, four-output intrinsically safe power supply for mining applications.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A small-sized, four-output intrinsically safe power supply for mining includes a flame-retardant protective shell, a circuit board, a base plate, glue injection holes, wiring studs, anti-loosening wiring nuts, hexagonal nuts, a first through hole, a second through hole, a third through hole, and a fourth through hole;

[0009] The first through hole is located on the flame-retardant protective shell; the second and third through holes are located on the circuit board; the fourth through hole is located on the base plate;

[0010] The flame-retardant protective shell is connected to the circuit board via wiring studs; the circuit board is connected to the base plate via hexagonal nuts.

[0011] Furthermore, the bottom end of the wiring stud is fixed to the circuit board by extending into the second through hole, and the top end extends into the first through hole and is fixed to the flame-retardant protective shell by an anti-loosening wiring nut.

[0012] Furthermore, the hexagonal nut extends sequentially into the third and fourth through holes to fix the circuit board to the base plate.

[0013] Furthermore, the injection hole is located at the top of the flame-retardant protective shell and is used to inject epoxy resin through the injection hole to seal the inside of the power supply.

[0014] Furthermore, the circuit board includes an input protection circuit and a 4-channel DC / DC conversion circuit;

[0015] The input protection circuit includes MOSFET Q1, MOSFET Q2, diode D1, diode D2, resistors R1, R2, R3, R4, R5, R6, R7 and capacitor C1.

[0016] The four-channel DC / DC conversion circuit includes four independent DC / DC conversion circuits. Each DC / DC conversion circuit includes an electromagnetic filter module, a PWM control module, a switching module, an overload protection module, a rectification / filtering module, a transformer, an output voltage detection module, an optocoupler, a current detection module, an MCU control module, a first switch, a second switch, and an over-temperature / over-voltage protection module.

[0017] The input protection circuit has a DC input terminal, including a positive and a negative terminal, and the input voltage is a DC voltage; the output terminal is connected to the input terminal of a 4-channel DC / DC conversion circuit.

[0018] Furthermore, in the input protection circuit, MOSFET Q1 is an N-type MOSFET with its drain grounded and its gate connected sequentially to resistors R4 and R1 and the positive terminal of the DC input terminal; MOSFET Q2 is an N-type MOSFET with its source connected to the source of MOSFET Q1, its drain connected to the negative terminal of the DC input terminal, and its gate connected sequentially to resistors R3 and R2 and the positive terminal of the DC input terminal; the anode of diode D1 is connected to the source of MOSFET Q2, and its cathode is connected between resistors R2 and R3; the anode of diode D2 is connected to the source of MOSFET Q1, and its cathode is connected between resistors R1 and R4; resistor R5 is connected in parallel with diode D1; resistor R6 is connected in parallel with diode D2; capacitor C1 is connected in parallel with resistor R6; and the two ends of resistor R7 are connected to the source and drain of MOSFET Q1, respectively.

[0019] Furthermore, the input terminal of the electromagnetic filter module is connected to the output terminal of the input protection circuit, and the output terminal is connected to the PWM control module; the input terminal of the PWM control module is connected to the overload protection module, and the output terminal is connected to the switching module; the input terminal of the overload protection module is connected to the switching module; the switching module and the rectification / filtering module are isolated by a transformer; the output voltage detection module transmits a feedback signal to the PWM control module through an optocoupler; the MCU control module is connected to the output voltage detection module through a first switch and to the current detection module through a second switch; the output terminal of the over-temperature / over-voltage protection module is connected to the MCU control module; both the first and second switches are connected to the voltage output terminal.

[0020] Furthermore, the input of the four-channel DC / DC conversion circuit is a single group of DC inputs, sharing an input protection circuit; the output is a power output, including four independent 12V outputs that are isolated from each other and have the same circuit structure.

[0021] Furthermore, when the positive and negative terminals of the DC input terminal of the input protection circuit are connected normally, the power output is normal; when the polarity of the DC input terminal is reversed, there is no power output.

[0022] The beneficial effects of this utility model are as follows:

[0023] (1) This utility model connects the components through studs, nuts and through holes, and seals them by injecting epoxy resin. It is small in size and does not require an explosion-proof shell or glue sealant during use, making it easy to install and maintain, and meeting the requirements for lightweight downhole equipment.

[0024] (2) The present invention has an input protection circuit at the DC input terminal, which can realize polarity reverse connection protection by using the conduction and turn-off of the MOS transistor, and suppress the current surge at the moment of power-on by the resistor connected to the DC input terminal, thus playing a dual protection role.

[0025] (3) This utility model outputs isolated DC voltage through 4 independent DC / DC conversion circuits, which can simultaneously power different intrinsically safe equipment, improve the cumbersome structure of traditional single power supply that requires multiple devices to be connected in parallel, and simplify the layout of the underground power supply system.

[0026] (4) Through the modular design of the DC / DC conversion circuit, this utility model enables each DC output to have an independent overcurrent, overvoltage and overcurrent protection module. Closed-loop control is achieved through the PWM control module and MCU control module, which can complete efficient and safe voltage conversion. Attached Figure Description

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0029] Figure 2 This is a schematic block diagram of the circuit board and module structure in this utility model.

[0030] Figure 3 This is a schematic diagram of the input protection circuit in this utility model.

[0031] In the diagram: 1. Flame-retardant protective shell, 2. Circuit board, 3. Base plate, 4. Injection hole, 5. Wiring stud, 6. Anti-loosening wiring nut, 7. Hex nut, 01. First through hole, 02. Second through hole, 03. Third through hole, 04. Fourth through hole. Detailed Implementation

[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. It should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "fixing", and "connection" should be interpreted broadly. For those skilled in the art, the specific meaning of the above terms in this patent can be understood according to the specific circumstances.

[0033] like Figure 1 As shown, a small-sized, four-output intrinsically safe power supply for mining includes a flame-retardant protective shell 1, a circuit board 2, a base plate 3, an injection hole 4, a terminal stud 5, a locking nut 6, a hexagonal nut 7, a first through hole 01, a second through hole 02, a third through hole 03, and a fourth through hole 04. The first through hole 01 is located on the flame-retardant protective shell 1, the second and third through holes 02 and 03 are located on the circuit board 2, and the fourth through hole 04 is located on the base plate 3.

[0034] In the specific connection method, the bottom end of the wiring stud 5 is fixed to the circuit board 2 by extending into the second through hole 02, and the top end extends into the first through hole 01 and is fixed to the flame-retardant protective shell 1 by the anti-loosening wiring nut 6, thereby connecting the flame-retardant protective shell 1 to the circuit board 2; the hexagonal nut 7 extends into the third through hole 03 and the fourth through hole 04 in sequence, thereby connecting the circuit board 2 to the base plate 3. This connection method fixes the circuit board 2 inside the power supply equipment, with a compact structure that facilitates installation, disassembly, and maintenance. Moreover, epoxy resin can be injected into the power supply equipment through the injection hole 4 at the top of the flame-retardant protective shell 1 to prevent underground coal dust and combustible gases from entering. While providing good sealing performance, it eliminates the need for additional mechanical explosion-proof components or metal explosion-proof shells. The power supply is small in size, easy to carry, and meets the requirements for lightweight underground equipment.

[0035] like Figure 2 As shown, circuit board 2 consists of an input protection circuit and a 4-channel DC / DC conversion circuit. The 4-channel DC / DC conversion circuit comprises four independent DC / DC conversion circuits, each consisting of an electromagnetic filter module, a PWM control module, a switching module, an overload protection module, a rectification / filtering module, a transformer, an output voltage detection module, an optocoupler, a current detection module, an MCU control module, a first switch, a second switch, and an over-temperature / over-voltage protection module. Figure 3 As shown, the input protection circuit consists of MOSFET Q1, MOSFET Q2, diode D1, diode D2, resistors R1, R2, R3, R4, R5, R6, R7 and capacitor C1.

[0036] It should be noted that the input voltage of the input protection circuit at the DC input terminal is preferably 18-36V DC voltage. Its output is a single DC input, which is shared by four mutually isolated DC / DC conversion circuits with the same circuit structure. Therefore, the final power output is divided into four channels, and the DC output of each channel is preferably 12V / 1.4A DC, which can simultaneously meet the power supply requirements of multiple intrinsically safe devices.

[0037] Specifically, in the input protection circuit, MOSFET Q1 is an N-type MOSFET with its drain grounded and its gate connected in sequence to resistors R4 and R1 and the positive terminal of the DC input. MOSFET Q2 is also an N-type MOSFET with its source connected to the source of MOSFET Q1, its drain connected to the negative terminal of the DC input, and its gate connected in sequence to resistors R3 and R2 and the positive terminal of the DC input. The anode of diode D1 is connected to the source of MOSFET Q2, and its cathode is connected between resistors R2 and R3. The anode of diode D2 is connected to the source of MOSFET Q1, and its cathode is connected between resistors R1 and R4. Resistor R5 is connected in parallel with diode D1. Resistor R6 is connected in parallel with diode D2. Capacitor C1 is connected in parallel with resistor R6. The two ends of resistor R7 are connected to the source and drain of MOSFET Q1, respectively.

[0038] It should be noted that the input protection circuit has dual protection functions: reverse polarity protection and power-on surge current limitation. The circuit working principle is as follows:

[0039] When the DC input is connected with normal polarity (positive to positive, negative to negative), the voltage output is normal. In this case, the positive terminal of the DC input provides a positive voltage to the gate of MOSFET Q1 through resistors R1 and R4, turning on MOSFET Q1; and provides a positive voltage to the gate of MOSFET Q2 through resistors R2 and R3, turning on MOSFET Q2. At this time, diodes D1 and D2 are reverse-biased and cut off; resistors R1, R2, R3, and R4 limit the gate charging current; and capacitor C1 slows down the rise time of the gate voltage of MOSFET Q1, thereby suppressing the power-on surge.

[0040] When the polarity of the DC input terminals is reversed, i.e., the positive terminal is connected to the negative terminal and the negative terminal to the positive terminal, there is no voltage output. In this case, the gate voltage of MOSFET Q1 is less than its source voltage, causing MOSFET Q1 to be turned off; the gate of MOSFET Q2 is pulled low through resistors R2 and R3, causing MOSFET Q2 to be turned off. Therefore, both current paths through MOSFETs Q1 and Q2 are cut off, and no voltage can be output. At this time, diodes D1 and D2 provide discharge paths, quickly releasing the gate charge, thereby accelerating the turn-off of MOSFETs Q1 and Q2; resistors R5 and R6 are connected in parallel with diodes D1 and D2 respectively, ensuring that the gate voltage can be pulled low and preventing the gate from floating; capacitor C1 and resistor R6 form an RC delay, thereby suppressing the gate voltage fluctuation at the moment of power-on; resistor R7 provides a discharge path to ground for the source of MOSFET Q1, preventing static electricity accumulation.

[0041] Specifically, in the DC / DC conversion circuit, the input terminal of the electromagnetic filter module is connected to the output terminal of the input protection circuit, and the output terminal is connected to the PWM control module; the input terminal of the PWM control module is connected to the overload protection module, and the output terminal is connected to the switching module; the input terminal of the overload protection module is connected to the switching module; the switching module and the rectification / filtering module are isolated by a transformer; the output voltage detection module transmits feedback signals to the PWM control module through an optocoupler; the MCU control module is connected to the output voltage detection module through a first switch and to the current detection module through a second switch; the output terminal of the over-temperature / over-voltage protection module is connected to the MCU control module; both the first and second switches are connected to the voltage output terminal.

[0042] It should be noted that the preferred overcurrent protection threshold is 1.5A, the preferred overvoltage protection threshold is 14V, and the preferred overtemperature protection threshold is 107℃. When the output current exceeds 1.5A, the overload protection module forces the duty cycle of the PWM control module to zero, and the switching module drives the transformer to stop working. When the output voltage exceeds 14V, the MCU control module disconnects the first switch, cutting off the power output. Simultaneously, the overvoltage detection module feeds back an overvoltage signal to the PWM control module via an optocoupler, and the PWM control module adjusts its duty cycle. When the temperature exceeds 107℃, the MCU control module disconnects the second switch, cutting off the power output. This modular design forms a closed-loop control structure of "output-feedback-adjustment" for the output voltage, achieving efficient and safe voltage conversion. Actual testing shows that it passes the short-circuit discharge spark test.

[0043] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A small-sized, four-output intrinsically safe power supply for mining, characterized in that: It includes a flame-retardant protective shell (1), a circuit board (2), a base plate (3), an injection hole (4), a wiring stud (5), an anti-loosening wiring nut (6), a hexagonal nut (7), a first through hole (01), a second through hole (02), a third through hole (03), and a fourth through hole (04); The first through hole (01) is located on the flame-retardant protective shell (1); the second through hole (02) and the third through hole (03) are located on the circuit board (2); the fourth through hole (04) is located on the base plate (3); The flame-retardant protective shell (1) is connected to the circuit board (2) via a wiring stud (5); the circuit board (2) is connected to the base plate (3) via a hexagonal nut (7).

2. The small-sized, four-output intrinsically safe power supply for mining as described in claim 1, characterized in that, The bottom end of the wiring stud (5) is fixed to the circuit board (2) by extending into the second through hole (02), and the top end extends into the first through hole (01) and is fixed to the flame-retardant protective shell (1) by the anti-loosening wiring nut (6).

3. A small-sized, four-output intrinsically safe power supply for mining as described in claim 1, characterized in that, The hexagonal nut (7) extends into the third through hole (03) and the fourth through hole (04) in sequence to fix the circuit board (2) onto the base plate (3).

4. A small-sized, four-output intrinsically safe power supply for mining as described in claim 1, characterized in that, The injection hole (4) is located at the top of the flame-retardant protective shell (1) and is used to inject epoxy resin through the injection hole (4) to seal the inside of the power supply.

5. A small-sized, four-output intrinsically safe power supply for mining according to claim 1, characterized in that, The circuit board (2) includes an input protection circuit and a 4-channel DC / DC conversion circuit; The input protection circuit includes MOSFET Q1, MOSFET Q2, diode D1, diode D2, resistors R1, R2, R3, R4, R5, R6, R7 and capacitor C1. The four-channel DC / DC conversion circuit includes four independent DC / DC conversion circuits. Each DC / DC conversion circuit includes an electromagnetic filter module, a PWM control module, a switching module, an overload protection module, a rectification / filtering module, a transformer, an output voltage detection module, an optocoupler, a current detection module, an MCU control module, a first switch, a second switch, and an over-temperature / over-voltage protection module. The input protection circuit has a DC input terminal, including a positive and a negative terminal, and the input voltage is a DC voltage; the output terminal is connected to the input terminal of a 4-channel DC / DC conversion circuit.

6. A small-sized, four-output intrinsically safe power supply for mining according to claim 5, characterized in that, In the input protection circuit, MOSFET Q1 is an N-type MOSFET with its drain grounded and its gate connected in sequence to resistors R4 and R1 and the positive terminal of the DC input. MOSFET Q2 is also an N-type MOSFET with its source connected to the source of MOSFET Q1, its drain connected to the negative terminal of the DC input, and its gate connected in sequence to resistors R3 and R2 and the positive terminal of the DC input. The anode of diode D1 is connected to the source of MOSFET Q2, and its cathode is connected between resistors R2 and R3. The anode of diode D2 is connected to the source of MOSFET Q1, and its cathode is connected between resistors R1 and R4. Resistor R5 is connected in parallel with diode D1. Resistor R6 is connected in parallel with diode D2. Capacitor C1 is connected in parallel with resistor R6. The two ends of resistor R7 are connected to the source and drain of MOSFET Q1, respectively.

7. A small-sized, four-output intrinsically safe power supply for mining according to claim 5, characterized in that, In the DC / DC conversion circuit, the input terminal of the electromagnetic filter module is connected to the output terminal of the input protection circuit, and the output terminal is connected to the PWM control module; the input terminal of the PWM control module is connected to the overload protection module, and the output terminal is connected to the switching module; the input terminal of the overload protection module is connected to the switching module; the switching module and the rectification / filtering module are isolated by a transformer; the output voltage detection module transmits a feedback signal to the PWM control module through an optocoupler; the MCU control module is connected to the output voltage detection module through a first switch and to the current detection module through a second switch; the output terminal of the over-temperature / over-voltage protection module is connected to the MCU control module; both the first and second switches are connected to the voltage output terminal.

8. A small-sized, four-output intrinsically safe power supply for mining according to claim 5, characterized in that, The input of the four-channel DC / DC conversion circuit is a single group of DC inputs, sharing an input protection circuit; the output is a power output, including four independent 12V outputs that are isolated from each other and have the same circuit structure.

9. A small-sized, four-output intrinsically safe power supply for mining according to claim 8, characterized in that, When the positive and negative terminals of the DC input terminal of the input protection circuit are connected normally, the power output is normal. When the polarity of the DC input terminal is reversed, there is no power output.

Images