Coal mine intrinsic safety direct current power supply protection control system

Abstract

The utility model provides a coal mine intrinsic safety direct current power supply protection control system which comprises a buffer starting circuit and an overvoltage protection circuit. The input end of the overvoltage protection circuit is connected to the positive electrode of the direct-current power supply, the output end of the overvoltage protection circuit is connected to the input end of the buffer starting circuit, and the output end of the buffer starting circuit is connected to the intrinsic safety power supply; the buffer starting circuit comprises a PMOS (P-channel Metal Oxide Semiconductor) tube Q5, a triode Q4, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a buffer capacitor C2 and a starting control circuit; the overvoltage protection detection and the power-on overvoltage protection can be firstly executed during input power-on, and low-current slow start can be realized during power-on, so that the impact of power-on current on the power supply is effectively prevented, the service life of components of the power supply is prolonged, and the reliability of the power supply is improved. And in addition, overvoltage detection and overvoltage protection actions can be executed in the operation process, so that the use safety risk is effectively reduced.

Description

Technical Field

[0001] The utility model relates to a mine power supply circuit, in particular to a coal mine intrinsically safe DC power supply protection control system. Background Art

[0002] In coal mines, intrinsically safe power supplies are required to power equipment. Mine intrinsically safe DC power supplies are used to process ordinary DC power supplies accordingly to obtain the DC power required by DC equipment in mines.

[0003] In the prior art, the input side of the intrinsically safe DC power supply for mines generally has no input protection. When connected to ordinary DC power, the DC power is directly injected into the intrinsically safe power supply for mines, which can easily cause impact damage to the intrinsically safe power supply during connection, thereby reducing the service life of the intrinsically safe power supply for mines and increasing safety risks. Although some intrinsically safe power supplies for mines are equipped with surge protection circuits, which can perform protection when there is an overvoltage shock, the circuit cannot play a buffering role when the DC voltage is normal.

[0004] Therefore, in order to solve the above technical problems, it is urgent to propose a new technical means. Utility Model Content

[0005] In view of this, the purpose of the utility model is to provide a coal mine intrinsically safe DC power supply protection and control system, which can first perform overvoltage protection detection and power-on overvoltage protection when the input is powered on, and can achieve small current slow start when powered on, effectively preventing the power-on current from impacting the power supply of this case, extending the service life of the components of the power supply of this case, and can also perform overvoltage detection and overvoltage protection actions during operation, effectively reducing the safety risk of use.

[0006] The utility model provides a coal mine intrinsically safe DC power supply protection control system, comprising a buffer start circuit and an overvoltage protection circuit;

[0007] The input end of the overvoltage protection circuit is connected to the positive electrode of the DC power supply, the output end of the overvoltage protection circuit is connected to the input end of the buffer startup circuit, and the output end of the buffer startup circuit is connected to the intrinsically safe power supply;

[0008] The buffer startup circuit includes a PMOS tube Q5, a transistor Q4, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a buffer capacitor C2 and a startup control circuit;

[0009] One end of the resistor R10 is connected to the output end of the overvoltage protection circuit as the input end of the buffer startup circuit, the other end of the resistor R10 is connected to the source of the PMOS tube Q5, the drain of the PMOS tube Q5 is grounded through the buffer capacitor C2, the common connection point between the drain of the PMOS tube Q5 and the buffer capacitor C2 is used as the output end of the buffer startup circuit, the source of the PMOS tube Q5 is connected to the gate of the PMOS tube Q5 through the resistor R9, the gate of the PMOS tube Q5 is connected to the collector of the transistor Q4 through the resistor R7, the emitter of the transistor Q4 is grounded, the base of the transistor Q4 is connected to the control output end of the startup control circuit, the source of the PMOS tube Q5 is connected to the drain of the PMOS tube Q5 through the resistor R8, and the startup control circuit is used to detect the voltage of the buffer capacitor C2 and control the transistor Q4 to turn on when the voltage reaches a set value.

[0010] Further, the startup control circuit includes a resistor R13, a resistor R11, a resistor R12, a resistor R6, a transistor Q2 and a transistor Q3;

[0011] The transistor Q3 is a P-type transistor, the emitter of the transistor Q3 is connected to the common connection point between the resistor R9 and the gate of the PMOS tube Q5, the collector of the transistor Q3 is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the base of the transistor Q4 as the control output end of the startup control circuit, one end of the resistor R13 is connected to the common connection point between the resistor R10 and the output end of the overvoltage protection circuit, the other end of the resistor R13 is connected to the collector of the transistor Q2 through the resistor R12, the emitter of the transistor Q2 is grounded, the base of the transistor Q2 is connected to one end of the resistor R13, the other end of the resistor R13 is connected to the common connection point between the drain of the PMOS tube Q5 and the capacitor C2 as the detection input end of the startup control circuit, and the common connection point between the resistor R13 and the resistor R12 is connected to the base of the transistor Q3.

[0012] Furthermore, the overvoltage protection circuit includes an overvoltage detection circuit and an overvoltage protection execution circuit, wherein the overvoltage detection circuit is used to detect whether the output voltage of the DC power supply is overvoltage, and input a control signal to the control input terminal of the overvoltage protection execution circuit when the output voltage is overvoltage;

[0013] The overvoltage protection execution circuit includes a normally open relay, a resistor R3, a resistor R4, a resistor R5, a resistor R14, a capacitor C1, a transistor Q1 and a thyristor SCR1;

[0014] One end of the normally open switch K1 of the normally open relay is connected to the positive electrode of the DC power supply as the input end of the overvoltage protection circuit, and the other end of the normally open switch K1 is connected to one end of the resistor R10 as the output end of the overvoltage protection circuit; the output end of the excitation coil J1 of the normally open relay is grounded, the input end of the excitation coil J1 of the normally open relay is connected to the emitter of the transistor Q1 through the resistor R4, one end of the resistor R3 is connected to the common connection point between the positive electrode of the DC power supply and the normally open switch K1, the other end of the resistor R3 is connected to the anode of the thyristor SCR1, the cathode of the thyristor SCR1 is grounded, the control electrode of the thyristor SCR1 serves as the control input end of the overvoltage protection execution circuit, the collector of the transistor Q1 is connected to the anode of the thyristor SCR1 through the resistor R14, the base of the transistor Q1 is connected to the anode of the thyristor SCR1 through the resistor R5, and the anode of the thyristor SCR1 is grounded through the capacitor C1.

[0015] Further, the overvoltage detection circuit includes a resistor R1, a voltage regulator tube ZD1, a voltage regulator tube ZD2 and a resistor R2;

[0016] One end of the resistor R1 is connected to the common connection point between the normally open switch K1 of the normally open relay and the positive electrode of the DC power supply as the input end of the overvoltage detection circuit, and the other end of the resistor R1 is connected to the negative electrode of the Zener diode ZD1, the positive electrode of the Zener diode ZD1 is connected to the negative electrode of the Zener diode ZD2, the positive electrode of the Zener diode ZD2 is grounded, the negative electrode of the Zener diode ZD2 is connected to one end of the resistor R2, and the other end of the resistor R2 serves as the output end of the overvoltage detection circuit.

[0017] Furthermore, the overvoltage detection circuit also includes a voltage regulator tube ZD3 and a light emitting diode LED1;

[0018] The cathode of the light-emitting diode LED1 is connected to the anode of the voltage-stabilizing tube ZD2, the anode of the light-emitting diode LED1 is grounded, the cathode of the voltage-stabilizing tube ZD3 is connected to the cathode of the voltage-stabilizing tube ZD2, the anode of the voltage-stabilizing tube ZD3 is connected to one end of the resistor R2, and the other end of the resistor R2 serves as the output end of the overvoltage detection protection circuit.

[0019] Furthermore, it also includes a bidirectional transient suppression diode TVS1, one end of which is connected to the common connection point between the normally open switch K1 and the positive electrode of the DC power supply, and the other end is grounded.

[0020] The beneficial effects of the utility model are as follows: through the utility model, overvoltage protection detection and power-on overvoltage protection can be performed first when the input is powered on, and a small current slow start can be achieved when the power is powered on, effectively preventing the impact of the power-on current on the power supply of this case, extending the service life of the components of the power supply of this case, and overvoltage detection and overvoltage protection actions can also be performed during operation, effectively reducing the safety risk of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The utility model is further described below in conjunction with the accompanying drawings and embodiments:

[0022] Figure 1 This is a circuit schematic diagram of the utility model. DETAILED DESCRIPTION

[0023] The utility model is further described in detail below:

[0024] The utility model provides a coal mine intrinsically safe DC power supply protection control system, comprising a buffer start circuit and an overvoltage protection circuit;

[0025] The input end of the overvoltage protection circuit is connected to the positive electrode of the DC power supply, the output end of the overvoltage protection circuit is connected to the input end of the buffer startup circuit, and the output end of the buffer startup circuit is connected to the intrinsically safe power supply;

[0026] The buffer startup circuit includes a PMOS tube Q5, a transistor Q4, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a buffer capacitor C2 and a startup control circuit;

[0027] One end of the resistor R10 is connected to the output end of the overvoltage protection circuit as the input end of the buffer startup circuit, the other end of the resistor R10 is connected to the source of the PMOS tube Q5, the drain of the PMOS tube Q5 is grounded through the buffer capacitor C2, the common connection point between the drain of the PMOS tube Q5 and the buffer capacitor C2 is used as the output end of the buffer startup circuit, the source of the PMOS tube Q5 is connected to the gate of the PMOS tube Q5 through the resistor R9, the gate of the PMOS tube Q5 is connected to the collector of the transistor Q4 through the resistor R7, the emitter of the transistor Q4 is grounded, the base of the transistor Q4 is connected to the control output end of the startup control circuit, the source of the PMOS tube Q5 is connected to the drain of the PMOS tube Q5 through the resistor R8, and the startup control circuit is used to detect the voltage of the buffer capacitor C2 and control the transistor Q4 to turn on when the voltage reaches a set value. Through the above structure, overvoltage protection detection and power-on overvoltage protection can be performed first when the input is powered on, and a small current slow start can be achieved when powered on, effectively preventing the power-on current from impacting the power supply of this case, extending the service life of the components of the power supply of this case, and overvoltage detection and overvoltage protection actions can also be performed during operation, effectively reducing the safety risk of use.

[0028] In this embodiment, the startup control circuit includes a resistor R13, a resistor R11, a resistor R12, a resistor R6, a transistor Q2 and a transistor Q3;

[0029] The transistor Q3 is a P-type transistor. The emitter of the transistor Q3 is connected to the common connection point between the resistor R9 and the gate of the PMOS tube Q5. The collector of the transistor Q3 is connected to one end of the resistor R6. The other end of the resistor R6 is connected to the base of the transistor Q4 as the control output end of the start control circuit. One end of the resistor R13 is connected to the common connection point between the resistor R10 and the output end of the overvoltage protection circuit. The other end of the resistor R13 is connected to the collector of the transistor Q2 through the resistor R12. The base of the transistor Q2 is grounded, the base of the transistor Q2 is connected to one end of the resistor R13, the other end of the resistor R13 is connected to the common connection point between the drain of the PMOS tube Q5 and the capacitor C2 as the detection input end of the startup control circuit, and the common connection point between the resistor R13 and the resistor R12 is connected to the base of the transistor Q3. Through the above structure, the conduction of the PMOS tube Q5 can be accurately controlled, and no active device is used in the control circuit, so that the structure of the entire circuit can be simplified and the use cost is lower.

[0030] When the power is just turned on, the current charges the capacitor C2 through the resistors R10 and R8. At this time, due to the common current limiting effect of R10 and R8, it is not enough to make the intrinsically safe power supply enter the working state. Moreover, since the terminal voltage of the capacitor C2 is not enough to turn on the transistor Q2, the transistor Q2 is turned off, the transistor Q3 is turned off, the transistor Q4 is turned off, and the PMOS tube Q5 is turned off. The capacitor C2 is charged so that its terminal voltage rises slowly, thereby preventing the impact on the intrinsically safe power supply. When the voltage of the capacitor C2 increases to the point where the transistor Q2 can still be turned on after the voltage is divided by the resistor R3, the transistor Q2 is turned on, the base potential of the transistor Q3 is lowered, the transistor Q3 is turned on, and then the transistor Q4 is turned on, the PMOS tube Q5 is turned on, and the resistor R8 is short-circuited. The intrinsically safe power supply can be powered normally, thereby realizing that the power-on process of the intrinsically safe power supply is a buffer process from small current to large current.

[0031] In this embodiment, the overvoltage protection circuit includes an overvoltage detection circuit and an overvoltage protection execution circuit, wherein the overvoltage detection circuit is used to detect whether the output voltage of the DC power supply is overvoltage, and input a control signal to the control input terminal of the overvoltage protection execution circuit when the output voltage is overvoltage;

[0032] The overvoltage protection execution circuit includes a normally open relay, a resistor R3, a resistor R4, a resistor R5, a resistor R14, a capacitor C1, a transistor Q1 and a thyristor SCR1;

[0033] One end of the normally open switch K1 of the normally open relay is connected to the positive electrode of the DC power supply as the input end of the overvoltage protection circuit, and the other end of the normally open switch K1 is connected to one end of the resistor R10 as the output end of the overvoltage protection circuit; the output end of the excitation coil J1 of the normally open relay is grounded, and the input end of the excitation coil J1 of the normally open relay is connected to the emitter of the transistor Q1 through the resistor R4, one end of the resistor R3 is connected to the common connection point between the positive electrode of the DC power supply and the normally open switch K1, and the other end of the resistor R3 is connected to the positive electrode of the DC power supply and ... The anode of the thyristor SCR1 and the cathode of the thyristor SCR1 are grounded, the control electrode of the thyristor SCR1 serves as the control input end of the overvoltage protection execution circuit, the collector of the transistor Q1 is connected to the anode of the thyristor SCR1 through the resistor R14, the base of the transistor Q1 is connected to the anode of the thyristor SCR1 through the resistor R5, and the anode of the thyristor SCR1 is grounded through the capacitor C1; in practice, it also includes a light emitting diode LED2, whose positive electrode is connected to the cathode of the thyristor SCR1 and whose negative electrode is grounded.

[0034] Wherein: the overvoltage detection circuit includes a resistor R1, a voltage regulator tube ZD1, a voltage regulator tube ZD2 and a resistor R2;

[0035] One end of the resistor R1 is connected to the common connection point between the normally open switch K1 of the normally open relay and the positive electrode of the DC power supply as the input end of the overvoltage detection circuit, and the other end of the resistor R1 is connected to the negative electrode of the Zener diode ZD1, the positive electrode of the Zener diode ZD1 is connected to the negative electrode of the Zener diode ZD2, the positive electrode of the Zener diode ZD2 is grounded, the negative electrode of the Zener diode ZD2 is connected to one end of the resistor R2, and the other end of the resistor R2 serves as the output end of the overvoltage detection circuit.

[0036] The overvoltage detection circuit also includes a voltage regulator tube ZD3 and a light emitting diode LED1;

[0037] The cathode of the light-emitting diode LED1 is connected to the anode of the voltage-stabilizing tube ZD2, the anode of the light-emitting diode LED1 is grounded, the cathode of the voltage-stabilizing tube ZD3 is connected to the cathode of the voltage-stabilizing tube ZD2, the anode of the voltage-stabilizing tube ZD3 is connected to one end of the resistor R2, and the other end of the resistor R2 serves as the output end of the overvoltage detection protection circuit. Whether it is powered on or in normal power supply operation, when the voltage and current are normal, ZD1 and ZD2 are cut off, and the thyristor SCR1 is cut off. At this time, the transistor Q1 is turned on, the excitation coil J1 of the relay is energized, and the normally open switch K1 is energized, thereby supplying power to the subsequent supply. When there is overvoltage or overcurrent (when overcurrent occurs, due to the action of R10, the voltage at the left end of R10 will increase, thereby showing as overvoltage), the voltage regulator ZD1 is turned on, and the voltage regulator ZD3 is turned on, thereby outputting a trigger current to the thyristor SCR1, the thyristor SCR1 is turned on, the light-emitting diode LED2 lights up, and the overvoltage or overcurrent indication warning is executed. After SCR1 is turned on, the three The pole tube Q1 is cut off, the excitation coil J1 of the relay is connected to the mains, and the normally open switch K1 is disconnected, thereby realizing overvoltage or overcurrent protection. Due to the trigger conduction characteristic of SCR1, the power supply can only be restored manually after the fault is eliminated, thereby preventing the reciprocating process of power supply conduction and disconnection (such as voltage fluctuations, short-term voltage recovery to normal in traffic, and repeated overvoltage) to prevent power supply accidents; the reverse conduction voltage of the voltage regulator ZD2 is much larger than the reverse conduction voltage of ZD1 and ZD3. Of course, the selection of ZD1 and ZD3 is determined according to the actual application voltage level of the intrinsically safe power supply, and ZD3 is used to prevent the reverse connection of the DC power supply and mistakenly trigger the thyristor SCR1.

[0038] LED1 is used for reverse connection indication. When the DC power supply is reversed, Figure 1 In the middle, it is positive at the bottom and negative at the top. At this time, a loop is formed from bottom to top for LED1, ZD2, ZD1, and R1, and the light-emitting diode LED1 lights up, indicating that the positive and negative directions of the DC power supply are reversed.

[0039] In this embodiment, a bidirectional transient suppression diode TVS1 is also included. One end of the bidirectional transient suppression diode TVS1 is connected to the common connection point between the normally open switch K1 and the positive electrode of the DC power supply, and the other end is grounded. When the voltage is too high, TVS1 is turned on, thereby providing surge protection. The on-state voltage of TVS1 is higher than the on-state voltage of ZD1. TVS1 and the overvoltage protection circuit described above form a two-stage voltage protection mechanism.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A coal mine intrinsically safe DC power supply protection control system, characterized in that: Including buffer startup circuit and overvoltage protection circuit; The input end of the overvoltage protection circuit is connected to the positive electrode of the DC power supply, the output end of the overvoltage protection circuit is connected to the input end of the buffer startup circuit, and the output end of the buffer startup circuit is connected to the intrinsically safe power supply; The buffer startup circuit includes a PMOS tube Q5, a transistor Q4, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a buffer capacitor C2 and a startup control circuit; One end of the resistor R10 is connected to the output end of the overvoltage protection circuit as the input end of the buffer startup circuit, the other end of the resistor R10 is connected to the source of the PMOS tube Q5, the drain of the PMOS tube Q5 is grounded through the buffer capacitor C2, the common connection point between the drain of the PMOS tube Q5 and the buffer capacitor C2 is used as the output end of the buffer startup circuit, the source of the PMOS tube Q5 is connected to the gate of the PMOS tube Q5 through the resistor R9, the gate of the PMOS tube Q5 is connected to the collector of the transistor Q4 through the resistor R7, the emitter of the transistor Q4 is grounded, the base of the transistor Q4 is connected to the control output end of the startup control circuit, the source of the PMOS tube Q5 is connected to the drain of the PMOS tube Q5 through the resistor R8, and the startup control circuit is used to detect the voltage of the buffer capacitor C2 and control the transistor Q4 to turn on when the voltage reaches a set value.

2. The coal mine intrinsically safe DC power supply protection control system according to claim 1 is characterized in that: The startup control circuit includes a resistor R13, a resistor R11, a resistor R12, a resistor R6, a transistor Q2 and a transistor Q3; The transistor Q3 is a P-type transistor, the emitter of the transistor Q3 is connected to the common connection point between the resistor R9 and the gate of the PMOS tube Q5, the collector of the transistor Q3 is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the base of the transistor Q4 as the control output end of the startup control circuit, one end of the resistor R13 is connected to the common connection point between the resistor R10 and the output end of the overvoltage protection circuit, the other end of the resistor R13 is connected to the collector of the transistor Q2 through the resistor R12, the emitter of the transistor Q2 is grounded, the base of the transistor Q2 is connected to one end of the resistor R13, the other end of the resistor R13 is connected to the common connection point between the drain of the PMOS tube Q5 and the capacitor C2 as the detection input end of the startup control circuit, and the common connection point between the resistor R13 and the resistor R12 is connected to the base of the transistor Q3.

3. The coal mine intrinsically safe DC power supply protection control system according to claim 2 is characterized in that: The overvoltage protection circuit comprises an overvoltage detection circuit and an overvoltage protection execution circuit, wherein the overvoltage detection circuit is used to detect whether the output voltage of the DC power supply is overvoltage, and input a control signal to the control input terminal of the overvoltage protection execution circuit when the output voltage is overvoltage; The overvoltage protection execution circuit includes a normally open relay, a resistor R3, a resistor R4, a resistor R5, a resistor R14, a capacitor C1, a transistor Q1 and a thyristor SCR1; One end of the normally open switch K1 of the normally open relay is connected to the positive electrode of the DC power supply as the input end of the overvoltage protection circuit, and the other end of the normally open switch K1 is connected to one end of the resistor R10 as the output end of the overvoltage protection circuit; the output end of the excitation coil J1 of the normally open relay is grounded, the input end of the excitation coil J1 of the normally open relay is connected to the emitter of the transistor Q1 through the resistor R4, one end of the resistor R3 is connected to the common connection point between the positive electrode of the DC power supply and the normally open switch K1, the other end of the resistor R3 is connected to the anode of the thyristor SCR1, the cathode of the thyristor SCR1 is grounded, the control electrode of the thyristor SCR1 serves as the control input end of the overvoltage protection execution circuit, the collector of the transistor Q1 is connected to the anode of the thyristor SCR1 through the resistor R14, the base of the transistor Q1 is connected to the anode of the thyristor SCR1 through the resistor R5, and the anode of the thyristor SCR1 is grounded through the capacitor C1.

4. The coal mine intrinsically safe DC power supply protection control system according to claim 3 is characterized in that: The overvoltage detection circuit includes a resistor R1, a voltage regulator tube ZD1, a voltage regulator tube ZD2 and a resistor R2; One end of the resistor R1 is connected to the common connection point between the normally open switch K1 of the normally open relay and the positive electrode of the DC power supply as the input end of the overvoltage detection circuit, and the other end of the resistor R1 is connected to the negative electrode of the Zener diode ZD1, the positive electrode of the Zener diode ZD1 is connected to the negative electrode of the Zener diode ZD2, the positive electrode of the Zener diode ZD2 is grounded, the negative electrode of the Zener diode ZD2 is connected to one end of the resistor R2, and the other end of the resistor R2 serves as the output end of the overvoltage detection circuit.

5. The coal mine intrinsically safe DC power supply protection control system according to claim 4 is characterized in that: The overvoltage detection circuit also includes a voltage regulator tube ZD3 and a light emitting diode LED1; The cathode of the light-emitting diode LED1 is connected to the anode of the voltage-stabilizing tube ZD2, the anode of the light-emitting diode LED1 is grounded, the cathode of the voltage-stabilizing tube ZD3 is connected to the cathode of the voltage-stabilizing tube ZD2, the anode of the voltage-stabilizing tube ZD3 is connected to one end of the resistor R2, and the other end of the resistor R2 serves as the output end of the overvoltage detection protection circuit.

6. The coal mine intrinsically safe DC power supply protection control system according to claim 3 is characterized by: It also includes a bidirectional transient suppression diode TVS1, one end of which is connected to a common connection point between the normally open switch K1 and the positive electrode of the DC power supply, and the other end is grounded.

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