High-low voltage output control circuit of explosion-proof quick-change power box for coal mine

Abstract

The invention provides a coal mine explosion-proof quick-change power box high-low voltage output control circuit which comprises a power conversion module, a voltage acquisition module and a reference voltage module. The voltage comparison module is used for simultaneously comparing the voltage output by the voltage acquisition module with the two reference voltages generated by the reference voltage module and simultaneously outputting two corresponding control signals; the high-voltage control module is used for controlling the on-off of a high-voltage contact of the explosion-proof quick-change power box according to the control signal and a control signal output by a BMS (Battery Management System) of the explosion-proof quick-change power box; the low-voltage control module is used for controlling the on-off of a low-voltage contact of the explosion-proof quick-change power box according to the control signal; and the CC2 mirror image module is used for detecting and judging whether a charger plug is connected or not for the BMS under the control of the control signal. According to the explosion-proof quick-change power supply box, the specially designed hardware circuit is additionally arranged in the existing explosion-proof quick-change power supply box, so that four technical problems of the existing explosion-proof quick-change power supply box can be effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply control for mining new energy vehicles, and in particular to a high and low voltage output control circuit of a coal mine explosion-proof quick-change power supply box. Background Art

[0002] At present, electric vehicles powered by power boxes are increasingly being used in coal mines as new energy vehicles, replacing traditional diesel vehicles. In order to improve the efficiency of various electric vehicles in coal mines, coal mine electric vehicles generally use integrated and quickly replaceable explosion-proof power boxes as the power source of electric vehicles. The structure of the explosion-proof quick-change power box commonly used in coal mine electric vehicles is as follows: Figure 1 As shown, it has a box, a socket fixed on the box, a battery pack for total power supply in the box, a switching power supply for obtaining power from the battery pack and converting it into low-voltage working power (24V), a BMS (battery management system) for battery management obtained from the switching power supply, a diode D for preventing the auxiliary power of the charger from backflowing into the low-voltage power (A+, A-) of the switching power supply in the power box during charging, and a maintenance switch K for controlling the output of high-voltage power (DC+, DC-) of the battery pack. When the explosion-proof quick-change power box needs to be charged, its socket is plugged into the plug of the matching charger to realize charging of the battery pack; when the explosion-proof quick-change power box is used on a new energy vehicle, its socket is plugged into the vehicle power plug of the new energy vehicle to realize power supply to the vehicle.

[0003] The existing explosion-proof quick-change power box has the following problems during use: First, since the vehicle plug is relatively large and heavy, when the operator plugs the vehicle plug into the socket of the explosion-proof quick-change power box, the A+ and A- contacts on the power box socket are repeatedly connected and disconnected with the low-voltage circuit of the vehicle due to unstable connection, which can easily damage the low-voltage equipment of the vehicle and even generate electric sparks, posing a huge safety hazard; second, when the socket of the explosion-proof quick-change power box is plugged into the plug of the charger, the low-voltage auxiliary power supply of the charger is connected to the switching power supply inside the power box through the A+ and A- contacts. Although the diode D provided can prevent the auxiliary power current from being fed back to the switching power supply by its unidirectionality, when the voltage of the auxiliary power supply is lower than the switching power supply voltage, it will cause the switching power supply to output current to the auxiliary power supply, and the power supply The switch power supply inside the box will still be disturbed, causing abnormal power supply of BMS, which will affect the normal charging and even cause danger; third, when the explosion-proof quick-change power box is replaced or stored, after the socket is separated from the charger plug or the vehicle plug, all contacts on the socket should be strictly prohibited from being energized according to regulations to avoid danger. In the prior art, this is achieved by manually disconnecting the maintenance switch K, but it relies on manual operation by relevant personnel, and it is easy to forget the operation, making the suspended high and low voltage contacts energized, which poses a great safety hazard; fourth, the on-off control of the high voltage electricity in the internal and external circuits of the power box is realized by the software built into the microprocessor in the BMS through the BMS control circuit (mainly relays). During the operation, the BMS software may fail or crash, and the use, installation and reliability need to be further improved; Summary of the invention

[0004] The purpose of the present invention is to provide a high and low voltage output control circuit of a coal mine explosion-proof quick-change power supply box, which completely solves the above four technical problems existing in the use of the existing coal mine explosion-proof quick-change power supply box.

[0005] The technical solution of the present invention is: the high and low voltage output control circuit of the coal mine explosion-proof quick-change power supply box of the present invention has the structural characteristics of comprising: The power conversion module is electrically connected to the output terminal of the switching power supply provided in the explosion-proof quick-change power supply box, and is used to convert the DC24V power output by the switching power supply into a DC12V power supply to provide working power; Voltage acquisition module, used to collect and output the voltage V between the detection contact CC2 and the protective ground contact PE of the explosion-proof quick-change power supply box O ; A reference voltage module, used to generate and output two reference voltages Vref1 and Vref2 for comparison and judgment; The voltage comparison module is used to compare the voltage V output by the voltage acquisition module OAt the same time, it compares with two reference voltages Vref1 and Vref2 generated by the reference voltage module, and outputs two corresponding control signals Ctr1 and Ctr2; The high-voltage control module is used to control the on-off of the high-voltage contacts DC+ and DC- of the explosion-proof quick-change power supply box according to the control signal Ctr1 output by the voltage comparison module and the control signal BMS_ctr1 and the control signal BMS_ctr2 output by the BMS of the explosion-proof quick-change power supply box; The low-voltage control module is used to control the on-off of the low-voltage contact A+ of the explosion-proof quick-change power supply box according to the control signal Ctr2 output by the voltage comparison module; The CC2 mirror module is used to provide a mirror resistor for the BMS of the explosion-proof quick-change power box to detect whether a charger plug is connected under the control of the control signals Ctr1 and Ctr2 output by the voltage comparison module.

[0006] A further solution is: the voltage acquisition module is composed of a voltage dividing resistor R1, one end of the voltage dividing resistor R1 is connected to the DC12V output end of the power conversion module, and the other end of the voltage dividing resistor R1 and the common contact of the detection contact CC2 of the explosion-proof quick-change power box constitute the voltage V of the voltage acquisition module O output end; accordingly, a matching resistor for collection and detection is preset in the vehicle plug of the new energy vehicle used in the explosion-proof quick-change power box.

[0007] A further solution is: the above-mentioned reference voltage module is composed of resistors R2, R3, R4, and R5, each end of the resistors R2 and R4 is electrically connected to the DC12V power output end of the power conversion module, each end of the resistors R3 and R5 is electrically connected to the protective ground contact PE of the explosion-proof quick-change power supply box, the other end of the resistor R2 and the other end of the resistor R3 have a common contact, and the common contact serves as the output end of the reference voltage Vref1, and the other end of the resistor R4 and the other end of the resistor R5 have a common contact, and the common contact serves as the output end of the reference voltage Vref2.

[0008] A further solution is that the voltage comparison module is composed of a dual voltage comparator integrated chip U1, and the No. 3 and No. 5 pins of the integrated chip U1 are connected to the voltage V O The output end is electrically connected, pins 2 and 6 of the integrated chip U1 are electrically connected to the reference voltage Vref1 and Vref2 output ends of the reference voltage module respectively, and pins 1 and 7 of the integrated chip U1 are used as output ends of control signals Ctr1 and Ctr2 respectively.

[0009] A further solution is: the high-voltage control module includes current limiting resistors R6 and R7, optocouplers U2 and U3, voltage dividing resistors R8, R9, R10 and R11, P-type MOS tubes Q1 and Q3 and a BMS control circuit, and the BMS control circuit includes relays K1 and K2, N-type MOS tubes Q2 and Q4 and pull-down resistors R12 and R13; The moving contact of relay K1 is electrically connected to the positive output terminal of the battery pack of the explosion-proof quick-change power supply box through the maintenance switch K of the explosion-proof quick-change power supply box, the static contact of relay K1 is electrically connected to the high-voltage positive contact DC+ of the explosion-proof quick-change power supply box, the negative terminal of the relay K1 coil is electrically connected to the No. 3 pin of the N-type MOS tube Q2, the No. 1 pin of the N-type MOS tube Q2, the control signal BMS_ctr1 output terminal of the BMS and one end of the pull-down resistor R12 have a common contact, the No. 2 pin of the N-type MOS tube Q2 and the other end of the pull-down resistor R12 are electrically connected to the negative pole of the 24V power output terminal of the switching power supply, and the relay K1 coil The positive terminal of the optocoupler U2 is electrically connected to the No. 3 pin of the P-type MOS tube Q1, the No. 2 pin of the P-type MOS tube Q1 and one end of the voltage-dividing resistor R8 are both electrically connected to the positive electrode of the 24V power output terminal, the No. 1 pin of the P-type MOS tube Q1, the other end of the voltage-dividing resistor R8 and one end of the voltage-dividing resistor R9 have a common contact, the other end of the voltage-dividing resistor R9 is electrically connected to the No. 4 pin of the optocoupler U2, and the No. 3 pin of the optocoupler U2 is electrically connected to the negative electrode of the 24V power output terminal of the switching power supply; the No. 1 pin of the optocoupler U2 is connected to the DC12V power output terminal of the power conversion module, and the No. 2 pin of the optocoupler U2 is connected to the output terminal of the control signal Ctr1 of the voltage comparison module through the current-limiting resistor R6; The moving contact of relay K2 is electrically connected to the negative output terminal of the battery pack, the static contact of relay K2 is electrically connected to the high-voltage negative contact DC- of the explosion-proof quick-change power supply box, the negative terminal of the relay K2 coil is electrically connected to pin 3 of the N-type MOS tube Q4, pin 1 of the N-type MOS tube Q4, the output terminal of the control signal BMS_ctr2 of the BMS, and one end of the pull-down resistor R13 have a common contact, pin 2 of the N-type MOS tube Q4 and the other end of the pull-down resistor R13 are both electrically connected to the negative pole of the 24V power output terminal of the switching power supply, and the positive terminal of the relay K2 coil is electrically connected to the P-type MOS tube Q3 Pin 3 of the optocoupler U3 is electrically connected, pin 2 of the P-type MOS tube Q3 and one end of the voltage-dividing resistor R10 are both electrically connected to the positive electrode of the 24V power supply output terminal, pin 1 of the P-type MOS tube Q3, the other end of the voltage-dividing resistor R10 and one end of the voltage-dividing resistor R11 have a common contact, the other end of the voltage-dividing resistor R11 is electrically connected to pin 4 of the optocoupler U3, and pin 3 of the optocoupler U3 is electrically connected to the negative electrode of the 24V power supply output terminal of the switching power supply; pin 1 of the optocoupler U3 is connected to the DC12V power supply output terminal of the power conversion module, and pin 2 of the optocoupler U3 is connected to the control signal Ctr1 output terminal of the voltage comparison module through the current-limiting resistor R7.

[0010] A further solution is: the above-mentioned low-voltage control module includes an optical coupler U4, an N-type MOS tube Q5, a relay K3 and a self-locking relay K4, a self-recovery button SW1, a current limiting resistor R14, and voltage-dividing resistors R15 and R16; The moving contact of relay K3 and the positive terminal of the coil and one end of the voltage-dividing resistor R15 are all connected to the 24V power output end of the switching power supply. The stationary contact of relay K3 and the positive terminal of the coil of self-locking relay K4 are all electrically connected to the low-voltage contact A+ of the explosion-proof quick-change power supply box. The negative terminal of the coil of relay K3, one end of the self-recovery button SW1 and the moving contact of self-locking relay K4 have a common contact. The stationary contact of self-locking relay K4, the other end of the self-recovery button SW1 and pin 3 of N-type MOS tube Q5 have a common contact. Pins 1 and 2 of N-type MOS tube Q5 are connected to the positive terminal of the coil of relay K3 and the positive terminal of the coil of self-locking relay K4. One end of the voltage-dividing resistor R16 and pin 3 of the optocoupler U4 have a common contact, pin 4 of the optocoupler U4 is electrically connected to the other end of the voltage-dividing resistor R15, pin 2 of the N-type MOS tube Q5, the other end of the voltage-dividing resistor R16, the negative terminal of the coil of the self-locking relay K4, the low-voltage contact A- of the explosion-proof quick-change power supply box and the negative pole of the 24V power output terminal of the switching power supply have a common contact, pin 1 of the optocoupler U4 is connected to the positive pole of the DC12V power output terminal of the power conversion module, and pin 2 of the optocoupler U4 is connected to the control signal Ctr2 output terminal of the voltage comparison module through the current limiting resistor R14.

[0011] A further solution is: the above-mentioned CC2 mirror module includes optocouplers U5 and U6 and resistors R17, R18, and R19; pin 1 of the optocoupler U5 is connected to the positive pole of the DC12V power output terminal of the power conversion module, pin 2 of the optocoupler U5 is connected to the Ctr1 control signal output terminal of the voltage comparison module through resistor R17, pin 1 of the optocoupler U6 is connected to the Ctr2 control signal output terminal of the voltage comparison module through resistor R18, pin 2 of the optocoupler U6 is connected to the protective ground contact PE of the explosion-proof quick-change power box, pin 3 of the optocoupler U5 is connected to pin 4 of the optocoupler U6 through resistor R19, and pin 4 of the optocoupler U5 and pin 3 of the optocoupler U6 are electrically connected to the BMS to provide the BMS with a detection signal for detecting whether the charger plug is plugged into the socket of the explosion-proof quick-change power box.

[0012] The present invention has positive effects: (1) The high and low voltage output control circuit of the coal mine explosion-proof quick-change power supply box of the present invention can effectively solve the four technical problems existing in the coal mine explosion-proof quick-change power supply box in the prior art through the design of the overall structure, specifically: Firstly, the high and low voltage output control circuit of the present invention is provided with a low voltage control module, and the low voltage control module works under the control of the control signal output by the voltage comparison module. Before the vehicle plug and the socket of the explosion-proof quick-change power box are not stably plugged in, the low voltage control module makes the low voltage A+ contact of the explosion-proof quick-change power box without electricity. Only after the plugging is stable, the self-recovery switch of the low voltage control module is pressed to make the self-locking relay self-lock, and then the low voltage A+ and A- contacts of the explosion-proof quick-change power box can be powered and output stably, thereby effectively solving the technical problem in the prior art that the vehicle plug is relatively large and heavy, and the operator will generate the A+ and A- contacts on the power box socket and the low voltage circuit of the vehicle repeatedly connected and disconnected due to unstable connection during the process of plugging the vehicle plug and the socket of the explosion-proof quick-change power box, which is easy to damage the low voltage equipment of the vehicle, and even generate electric sparks to bring huge safety hazards; Secondly, when the socket of the explosion-proof quick-change power box is connected to the plug of the charger, the low-voltage control module, under the control of the control signal output by the voltage comparison module, disconnects the low-voltage A+ contact of the explosion-proof quick-change power box from the internal switching power supply, thereby effectively solving the technical problem in the prior art that when the voltage of the auxiliary power supply is lower than the voltage of the switching power supply, the switching power supply outputs current to the auxiliary power supply, and the switching power supply inside the power box is still disturbed, causing abnormal power supply of the BMS, thereby affecting the normal charging and even causing dangerous technical problems; Thirdly, when the high and low voltage output control circuit of the present invention detects that the explosion-proof quick-change power supply box is being replaced or stored, that is, when the contacts of the explosion-proof quick-change power supply box are suspended, the high voltage control module and the low voltage control module control the two high voltage contacts DC+ and DC- and the low voltage contact A+ of the explosion-proof quick-change power supply box through the hardware circuit to be de-energized, thereby effectively solving the technical problem in the prior art that the operation of disconnecting the maintenance switch K by manual operation is prone to forgetting the operation, making the suspended high and low voltage contacts energized, thereby posing a great safety hazard; Fourthly, the high-voltage control module of the high- and low-voltage output control circuit of the present invention makes further improvements to the circuit on the basis of retaining the existing BMS control circuit, thereby adding a redundant backup of safety and reliability for the on-off control of the high-voltage electricity inside and outside the existing power box, thereby effectively solving the technical problem in the prior art that the on-off of the high-voltage electricity inside and outside the power box is realized only by the software built into the microprocessor in the BMS through the BMS control circuit, and the installation and reliability of the high-voltage electricity on-off need to be further improved due to failure or crash of the BMS software.

[0013] (2) The high and low voltage output control circuit of the explosion-proof quick-change power box of the coal mine of the present invention outputs different voltage signals according to the different resistances between the CC2 contact and the PE contact of the explosion-proof quick-change power box by setting a voltage acquisition module, so as to distinguish whether the socket inserted into the explosion-proof quick-change power box is connected to the charger plug or the vehicle plug or is left hanging. The voltage comparison module combines the reference voltage output by the reference voltage reference module to output different high and low level combination control signals to control the high voltage control module and the low voltage control module to perform corresponding control actions. The whole circuit is a pure hardware circuit, which does not rely on a microcontroller or a program, has good real-time performance and high reliability.

[0014] (3) The high and low voltage output control circuit of the coal mine explosion-proof quick-change power supply box of the present invention solves the problem that in the prior art, the resistor between the CC2 contact and the PE contact on the charging plug is connected to the BMS for the BMS to determine whether a charger is connected, but in the circuit of the present invention, a voltage sampling module is connected between the CC2 contact and the PE contact. A CC2 mirror module is creatively provided to generate a "mirror" resistor according to a control signal for the BMS to detect and determine whether a charging plug is connected, thereby solving this problem. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the structure of the explosion-proof quick-change power supply box currently commonly used in coal mines, and the figure also schematically shows its connection relationship with the charger during charging; Figure 2 It is a structural schematic diagram of an explosion-proof quick-change power supply box adopting the high and low voltage output control circuit of the present invention; Figure 3 for Figure 2 The electrical schematic diagram of the medium voltage acquisition module. At this time, the socket of the explosion-proof quick-change power supply box is suspended, and the detection contact CC2 of the socket is disconnected from the protective ground contact PE; Figure 4 for Figure 2 The electrical schematic diagram of the medium voltage acquisition module. At this time, the socket of the explosion-proof quick-change power supply box is plugged into the plug of the charger, and the 1kΩ resistor built into the charger is connected between the detection contact CC2 of the socket and the protective ground contact PE; Figure 5 for Figure 2 The electrical schematic diagram of the medium voltage acquisition module. At this time, the socket of the explosion-proof quick-change power box is plugged into the vehicle plug, and a 200Ω resistor pre-set in the vehicle plug is connected between the detection contact CC2 of the socket and the protective ground contact PE; Figure 6 for Figure 2 An electrical schematic diagram of a reference voltage module; Figure 7 for Figure 2An electrical schematic diagram of a medium voltage comparison module; Figure 8 for Figure 2 An electrical schematic diagram of a medium and high voltage control module. The dashed box in the figure shows the existing BMS control circuit of the explosion-proof quick-change power supply box; Fig. 9 for Figure 2 An electrical schematic diagram of a medium and low voltage control module; Fig.10 for Figure 2 An electrical schematic diagram of the CC2 mirror module. DETAILED DESCRIPTION

[0016] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0017] (Example 1) See Figure 2 The high and low voltage output control circuit of the coal mine explosion-proof quick-change power supply box of this embodiment is installed in the existing explosion-proof quick-change power supply box when in use. It is mainly composed of a power conversion module, a voltage acquisition module, a reference voltage module, a voltage comparison module, a high voltage control module, a low voltage control module, and a CC2 mirror module.

[0018] The power conversion module is electrically connected to the output terminal of the existing switching power supply in the explosion-proof quick-change power supply box, and is used to convert the DC24V power output by the switching power supply into a DC12V power supply to provide working power for the control circuit of the present invention. The power conversion module is a mature prior art, and its specific circuit structure is not described in detail.

[0019] See also Figures 3 to 5 , voltage acquisition module, used to collect and output the voltage V between the detection contact CC2 and the protective ground contact PE of the explosion-proof quick-change power box O And according to different voltage V O To distinguish the connection object of the explosion-proof quick-change power supply box; as a specific implementation, in this embodiment, the voltage acquisition module is composed of a 1kΩ voltage-dividing resistor R1, one end of the voltage-dividing resistor R1 is connected to the DC12V output end of the power conversion module, and the other end of the voltage-dividing resistor R1 and the common contact of the detection contact CC2 of the explosion-proof quick-change power supply box constitute the voltage acquisition output end of the voltage acquisition module. Figure 3 As shown in the figure, when the detection contact CC2 of the explosion-proof quick-change power supply box is suspended with the protective ground contact PE, the output voltage V O For DC12V; Figure 4 As shown in the figure, when the charger plug is connected to the socket of the explosion-proof quick-change power box, a 1kΩ resistor (according to the national standard) built into the charger plug is connected between the detection contact CC2 of the explosion-proof quick-change power box and the protective ground contact PE. At this time, the output voltage V OFor DC6V; Figure 5 As shown, the present invention presets a 200Ω resistor in the vehicle plug (specially set up by the present invention). When the vehicle plug is plugged into the socket of the explosion-proof quick-change power box, a 200Ω resistor is connected between the detection contact CC2 and the protective ground contact PE of the explosion-proof quick-change power box. At this time, the output voltage V O It is DC2V.

[0020] The reference voltage module is used to generate two reference voltages Vref1 and Vref2 for comparison and judgment. As a specific implementation, in this embodiment, Figure 6 As shown, the reference voltage module is composed of resistors R2, R3, R4, and R5. One end of each resistor R2 and R4 is electrically connected to the DC12V power output end of the power conversion module, and one end of each resistor R3 and R5 is electrically connected to the protective ground contact PE of the explosion-proof quick-change power supply box. The other end of the resistor R2 and the other end of the resistor R3 have a common contact as the output end of the reference voltage Vref1, and the other end of the resistor R4 and the other end of the resistor R5 have a common contact as the output end of the reference voltage Vref2. In this embodiment, the resistance values ​​of the resistors R2, R3, R4, and R5 are selected to be 1kΩ, 2kΩ, 1kΩ, and 500Ω, and the corresponding output reference voltages Vref1 and Vref2 are 8V and 4V.

[0021] The voltage comparison module is used to compare the output voltage V O At the same time, the reference voltage module compares the two reference voltages Vref1 and Vref2 generated by the reference voltage module and outputs two corresponding control signals Ctr1 and Ctr2. Figure 7 As shown, the voltage comparison module is composed of a dual voltage comparator integrated circuit U1 of the LM393 model (i.e., LM393 integrated chip U1). The 3rd and 5th pins of the LM393 integrated chip U1 are both connected to the voltage V O The output end is electrically connected, the 2nd and 6th pins of the LM393 integrated chip U1 are electrically connected to the reference voltages Vref1 and Vref2 generated by the reference voltage module, and the 1st and 7th pins of the LM393 integrated chip U1 output Ctr1 and Ctr2 control signals respectively. When the charger plug is plugged into the socket of the explosion-proof quick-change power box, the voltage sampling module outputs the voltage V O 6V( Figure 4 ), at this time Ctr1 outputs low level, Ctr2 outputs high level; when the vehicle plug is plugged into the explosion-proof quick-change power box, the voltage sampling module outputs the voltage V O 2V( Figure 5), at this time, Ctr1 and Ctr2 output low level at the same time; when the explosion-proof quick-change power supply box is suspended, that is, there is no connected device, the voltage sampling module outputs voltage V O 12V( Figure 3 ), at this time, Ctr1 and Ctr2 output high level at the same time. The voltage comparison module controls the operation of the next level high voltage control module, low voltage control module and CC2 mirror module through the output Ctr1 and Ctr2 level signals.

[0022] The high voltage control module is used to control the on and off of the high voltage contacts DC+ and DC- of the explosion-proof quick-change power supply box according to the control signal Ctr1 output by the voltage comparison module and the control signal BMS_ctr1 and the control signal BMS_ctr2 output by the BMS of the explosion-proof quick-change power supply box. As a specific implementation, in this embodiment, the high voltage control module is as follows Figure 8 As shown, on the basis of the existing BMS control circuit, current limiting resistors R6 and R7, optocouplers U2 and U3, voltage divider resistors R8, R9, R10 and R11, and P-type MOS tubes Q1 and Q3 are added. The existing BMS control circuit is composed of relays K1 and K2, N-type MOS tubes Q2 and Q4, and pull-down resistors R12 and R13. In this embodiment, optocouplers U2 and U3 preferably use TLP185 type optocouplers, P-type MOS tubes Q1 and Q3 use IRFR9024NTRPBF type MOS tubes, and N-type MOS tubes Q2 and Q4 use NTD3055L104T4G type MOS tubes.

[0023] The moving contact 11 of the relay K1 is electrically connected to the positive output terminal Batt+ of the battery pack through the maintenance switch K, the static contact 14 of the relay K1 is electrically connected to the high-voltage positive contact DC+ of the explosion-proof quick-change power supply box, the negative terminal A1 of the relay K1 coil is electrically connected to the No. 3 pin of the N-type MOS tube Q2, the No. 1 pin of the N-type MOS tube Q2, the control signal BMS_ctr1 output terminal of the BMS and one end of the pull-down resistor R12 have a common contact, the No. 2 pin of the N-type MOS tube Q2 and the other end of the pull-down resistor R12 are electrically connected to the negative pole of the 24V power output terminal of the switching power supply, that is, 24VGND, which is different from the prior art in which the positive terminal A2 of the relay K1 coil is directly connected to the positive pole of the 24V power output terminal, that is, +24V The difference is that, in this embodiment, the positive electrode terminal A2 of the relay K1 coil is electrically connected to the No. 3 pin of the P-type MOS tube Q1, the No. 2 pin of the P-type MOS tube Q1 and one end of the voltage-dividing resistor R8 are both electrically connected to the positive electrode of the 24V power supply output terminal, that is, +24V, the No. 1 pin of the P-type MOS tube Q1, the other end of the voltage-dividing resistor R8 and one end of the voltage-dividing resistor R9 have a common contact, the other end of the voltage-dividing resistor R9 is electrically connected to the No. 4 pin of the optocoupler U2, and the No. 3 pin of the optocoupler U2 is electrically connected to the negative electrode of the 24V power supply output terminal of the switching power supply; the No. 1 pin of the optocoupler U2 is connected to the positive electrode +12V of the DC12V power supply output terminal of the power conversion module, and the No. 2 pin of the optocoupler U2 is connected to the output end of the control signal Ctr1 of the voltage comparison module through the current-limiting resistor R6.

[0024] Basically the same, the moving contact 11 of the relay K2 is electrically connected to the negative output terminal Batt- of the battery pack, the static contact 14 of the relay K2 is electrically connected to the high-voltage negative contact DC- of the explosion-proof quick-change power supply box, the negative terminal A1 of the relay K2 coil is electrically connected to the No. 3 pin of the N-type MOS tube Q4, the No. 1 pin of the N-type MOS tube Q4, the BMS control signal BMS_ctr2 output terminal and one end of the pull-down resistor R13 have a common contact, and the No. 2 pin of the N-type MOS tube Q4 and the other end of the pull-down resistor R13 are electrically connected to the negative pole of the 24V power output terminal of the switching power supply, that is, 24VGND, which is different from the prior art in which the positive terminal A2 of the relay K2 coil is directly electrically connected to the positive pole of the 24V power output terminal, that is, +24V. In this embodiment, the positive electrode terminal A2 of the relay K2 coil is electrically connected to the No. 3 pin of the P-type MOS tube Q3, the No. 2 pin of the P-type MOS tube Q3 and one end of the voltage-dividing resistor R10 are both electrically connected to the positive electrode of the 24V power output terminal, that is, +24V, the No. 1 pin of the P-type MOS tube Q3, the other end of the voltage-dividing resistor R10 and one end of the voltage-dividing resistor R11 have a common contact, the other end of the voltage-dividing resistor R11 is electrically connected to the No. 4 pin of the optocoupler U3, and the No. 3 pin of the optocoupler U3 is electrically connected to the negative electrode of the 24V power output terminal of the switching power supply; the No. 1 pin of the optocoupler U3 is connected to the positive electrode +12V of the DC12V power output terminal of the power conversion module, and the No. 2 pin of the optocoupler U3 is connected to the output end of the control signal Ctr1 of the voltage comparison module through the current-limiting resistor R7.

[0025] The working principle of the high-voltage control module of this embodiment is explained by taking the control of the power on and off of the high-voltage positive contact DC+ of the explosion-proof quick-change power box as an example: when the socket of the explosion-proof quick-change power box is not connected to the charger plug or the vehicle plug, that is, the socket of the explosion-proof quick-change power box is suspended, as mentioned above, since the control signal Ctr1 remains at a high level (+12V), the optocoupler U2 is cut off, and the P-type MOS tube Q1 also remains cut off. At this time, even if the control signal BMS_ctr1 sent by the BMS turns on the N-type MOS tube Q2, since the coil of the relay K1 is not energized, the moving contact 11 and the static contact 14 of the relay K1 still cannot be closed. This ensures that the socket of the explosion-proof quick-change power box is not connected to a charger plug or a vehicle plug, that is, when the socket is suspended, the positive high-voltage contact DC+ of the socket is not energized; when the socket of the explosion-proof quick-change power box is connected to a charger plug or a vehicle plug, as mentioned above, since the level signal Ctr1 remains at a low level, the optocoupler U2 is turned on, and the P-type MOS tube Q1 also remains on. At this time, the BMS can control the cutoff or conduction of the N-type MOS tube Q2 through the control signal BMS_ctr1, and the corresponding control relay K1 is turned on and off, thereby controlling the positive high-voltage contact DC+ of the socket to be turned on or off, that is, energized or not energized. The control principle of the high-voltage control module for the negative high-voltage contact DC- of the socket to be turned on or off, that is, energized or not energized is the same as DC+, and will not be repeated.

[0026] The low voltage control module is used to control the on / off of the low voltage contact A+ of the explosion-proof quick-change power supply box according to the control signal Ctr2 output by the voltage comparison module. As a specific implementation, in this embodiment, the low voltage control module is as follows Fig. 9 As shown, it is mainly composed of an optical coupler U4, an N-type MOS tube Q5, a relay K3 and a self-locking relay K4, a self-recovery button SW1, a current limiting resistor R14, and voltage-dividing resistors R15 and R16. In this embodiment, the optical coupler U4 preferably adopts a TLP185 optical coupler, and the N-type MOS tubes Q2 and Q4 adopt NTD3055L104T4G MOS tubes.

[0027] The moving contact 11 of the relay K3 and the positive terminal A2 of the coil and one end of the voltage-dividing resistor R15 are all connected to the positive pole of the 24V power output terminal of the switching power supply. The stationary contact 14 of the relay K3 and the positive terminal A2 of the coil of the self-locking relay K4 are all electrically connected to the low-voltage contact positive pole A+ of the explosion-proof quick-change power supply box. The negative terminal A1 of the coil of the relay K3, one end of the self-recovery button SW1 and the moving contact 11 of the self-locking relay K4 have a common contact. The stationary contact 14 of the self-locking relay K4, the other end of the self-recovery button SW1 and the No. 3 pin of the N-type MOS tube Q5 have a common contact. The No. 1 pin, One end of the voltage-dividing resistor R16 and pin 3 of the optocoupler U4 have a common contact, pin 4 of the optocoupler U4 is electrically connected to the other end of the voltage-dividing resistor R15, pin 2 of the N-type MOS tube Q5, the other end of the voltage-dividing resistor R16, the negative terminal A1 of the coil of the self-locking relay K4, the negative pole A- of the low-voltage contact of the explosion-proof quick-change power supply box, and the negative pole of the 24V power output terminal of the switching power supply, i.e., 24VGND, have a common contact, pin 1 of the optocoupler U4 is connected to the positive pole +12V of the DC12V power output terminal of the power conversion module, and pin 2 of the optocoupler U4 is connected to the output end of the control signal Ctr2 of the voltage comparison module through the current-limiting resistor R14.

[0028] The working principle of the low-voltage control module is: when the socket of the explosion-proof quick-change power box is suspended or connected to a charger, as the aforementioned control signal Ctr2 maintains a high level (+12V), the optocoupler U4 is cut off, and the N-type MOS tube Q5 also remains cut off. Regardless of whether the self-resetting switch SW1 is activated or not, the coil of the relay K3 cannot be turned on, and the moving contact 11 and the static contact 14 of K3 remain in the disconnected state, so that the 24V output positive pole of the switching power supply is also disconnected from the A+ contact on the socket of the explosion-proof quick-change power box; and when the socket of the explosion-proof quick-change power box is connected to the vehicle plug, as the control signal Ctr2 mentioned above remains at a low level, the optocoupler U4 is turned on, and the N-type MOS tube Q5 is also turned on. At this time, by pressing the self-resetting switch SW1 again, on the one hand, the coil of the relay K3 is energized, and its moving contact 11 and the static contact 14 are closed, and the output 24V output positive pole of the switching power supply is connected to the A+ contact on the socket of the explosion-proof quick-change power box; at the same time, after the contacts of the relay K3 are closed, the coil of the self-locking relay K4 is energized to close its moving contact 11 and the static contact 14. At this time, the self-resetting switch SW1 is released, and the coil of the relay K3 will still be energized and the contacts will still remain closed. The function of the self-resetting switch SW1 and the self-locking relay K4 is that when the connection between the plug and the socket is not stable during the plug-in and unplugging process, even if the CC2 contacts of the plug and the socket are repeatedly in contact and disconnected, since the self-resetting switch SW1 and the self-locking relay K4 are disconnected, the relay K3 will remain disconnected until the connection between the plug and the socket is stable and the user presses the self-resetting switch SW1, and then the A+ contact on the quick-change power box socket will be turned on, which can effectively solve the technical problem that due to the relatively large and heavy body of the vehicle plug, the operator will produce the technical problem that the A+ and A- contacts on the power box socket and the low-voltage circuit of the vehicle are repeatedly connected and disconnected due to the unstable connection during the plug-in process of the vehicle plug and the explosion-proof quick-change power box, which is easy to damage the low-voltage equipment of the vehicle and even generate electric sparks and bring huge safety hazards. At the same time, it solves the technical problem that when the voltage of the auxiliary power supply of the charger is lower than the voltage of the switching power supply, the switching power supply will still be disturbed when outputting current to the auxiliary power supply, causing abnormal BMS power supply, thus affecting the normal charging and even causing danger.

[0029] The CC2 mirror module is used to provide a mirror resistor for the BMS of the explosion-proof quick-change power box to detect whether a charger plug is connected under the control of the control signals Ctr1 and Ctr2 output by the voltage comparison module. According to the relevant provisions of the national standard "GB / T18487.1-2015", the BMS in the explosion-proof quick-change power box determines whether the explosion-proof quick-change power box is connected to the charger by detecting the resistance between the CC2 contact and the PE contact on the charging plug. When the charging plug is inserted into the socket of the explosion-proof quick-change power box, the resistance between the CC2 contact and the PE contact in the prior art should be connected to the detection interface of the BMS, but in the circuit of the present invention, the voltage sampling module of the present invention is connected between the CC2 contact and the PE contact on the charging plug. Therefore, it is necessary to add another "mirror" resistor for the BMS to detect and determine whether a charging plug is connected. As a specific implementation method, in this embodiment, the CC2 mirror module is as follows Fig.10 As shown, it is mainly composed of optocouplers U5 and U6, and resistors R17, R18, and R19. Pin 1 of the optocoupler U5 is connected to the positive pole +12V of the DC12V power output terminal of the power conversion module, and pin 2 of the optocoupler U5 is connected to the Ctr1 control signal output terminal of the voltage comparison module through resistor R17. Pin 1 of the optocoupler U6 is connected to the Ctr2 control signal output terminal of the voltage comparison module through resistor R18. Pin 2 of the optocoupler U6 is connected to the protective ground contact PE of the explosion-proof quick-change power box, and pin 3 of the optocoupler U5 is connected to pin 4 of the optocoupler U6 through resistor R19. Pin 4 (CC2_out) of the optocoupler U5 and pin 3 (PE_out) of the optocoupler U6 are electrically connected to the resistance detection interface of the BMS, and the resistance value of resistor R19 is 1kΩ. In this embodiment, the optocouplers U5 and U6 preferably use TLP185 model optocouplers.

[0030] The working principle of the CC2 mirror module is: when the charging plug of the charger is inserted into the socket of the explosion-proof quick-change power box, as mentioned above, Ctr1 is low level, Ctr2 is high level, optocouplers U5 and U6 are turned on at the same time, and the 1kΩ resistor R19 is connected to the CC2 detection circuit of the BMS; when the vehicle plug is plugged into the socket of the explosion-proof quick-change power box, since Ctr1 and Ctr2 are both low level, optocoupler U5 is turned on, optocoupler U6 is turned off, and the CC2 detection circuit of the BMS cannot detect the R19 resistor; when the socket of the explosion-proof quick-change power box is suspended, since Ctr1 and Ctr2 are both high level, optocoupler U5 is turned off, optocoupler U6 is turned on, and the CC2 detection circuit of the BMS still cannot detect the R19 resistor. Therefore, by setting the CC2 mirror module, the BMS can accurately judge whether the charging plug of the charger is plugged into the socket of the explosion-proof quick-change power box as in the prior art.

[0031] The above embodiments are descriptions of specific implementation methods of the present invention rather than limitations of the present invention. Technical personnel in the relevant technical field can make various changes and modifications to obtain corresponding equivalent technical solutions without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should be included in the patent protection scope of the present invention.

Claims

1. A high and low voltage output control circuit for a coal mine explosion-proof quick-change power supply box, characterized in that: include: The power conversion module is electrically connected to the output terminal of the switching power supply provided in the explosion-proof quick-change power supply box, and is used to convert the DC24V power output by the switching power supply into a DC12V power supply to provide working power; Voltage acquisition module, used to collect and output the voltage V between the detection contact CC2 and the protective ground contact PE of the explosion-proof quick-change power supply box O ; A reference voltage module, used to generate and output two reference voltages Vref1 and Vref2 for comparison and judgment; The voltage comparison module is used to compare the voltage V output by the voltage acquisition module O At the same time, it compares with two reference voltages Vref1 and Vref2 generated by the reference voltage module, and outputs two corresponding control signals Ctr1 and Ctr2; The high-voltage control module is used to control the on-off of the high-voltage contacts DC+ and DC- of the explosion-proof quick-change power supply box according to the control signal Ctr1 output by the voltage comparison module and the control signal BMS_ctr1 and the control signal BMS_ctr2 output by the BMS of the explosion-proof quick-change power supply box; The low-voltage control module is used to control the on-off of the low-voltage contact A+ of the explosion-proof quick-change power supply box according to the control signal Ctr2 output by the voltage comparison module; The CC2 mirror module is used to provide a mirror resistor for the BMS of the explosion-proof quick-change power box to detect whether a charger plug is connected under the control of the control signals Ctr1 and Ctr2 output by the voltage comparison module.

2. The high and low voltage output control circuit of the coal mine explosion-proof quick-change power supply box according to claim 1 is characterized in that: The voltage acquisition module is composed of a voltage dividing resistor R1, one end of which is connected to the DC12V output end of the power conversion module, and the other end of the voltage dividing resistor R1 and the common contact of the detection contact CC2 of the explosion-proof quick-change power box form the voltage V of the voltage acquisition module. O output end; accordingly, a matching resistor for collection and detection is preset in the vehicle plug of the new energy vehicle used in the explosion-proof quick-change power box.

3. The high and low voltage output control circuit of the coal mine explosion-proof quick-change power supply box according to claim 1 is characterized in that: The reference voltage module is composed of resistors R2, R3, R4, and R5. Each end of the resistors R2 and R4 is electrically connected to the DC12V power output end of the power conversion module, and each end of the resistors R3 and R5 is electrically connected to the protective ground contact PE of the explosion-proof quick-change power supply box. The other end of the resistor R2 and the other end of the resistor R3 have a common contact, which serves as the output end of the reference voltage Vref1. The other end of the resistor R4 and the other end of the resistor R5 have a common contact, which serves as the output end of the reference voltage Vref2.

4. The high and low voltage output control circuit of the coal mine explosion-proof quick-change power supply box according to claim 1 is characterized in that: The voltage comparison module is composed of a dual voltage comparator integrated chip U1. The integrated chip U1 has pins 3 and 5 that are connected to the voltage V of the voltage acquisition module. O The output end is electrically connected, pins 2 and 6 of the integrated chip U1 are electrically connected to the reference voltage Vref1 and Vref2 output ends of the reference voltage module respectively, and pins 1 and 7 of the integrated chip U1 are used as output ends of control signals Ctr1 and Ctr2 respectively.

5. The high and low voltage output control circuit of the coal mine explosion-proof quick-change power supply box according to claim 1 is characterized in that: The high-voltage control module includes current-limiting resistors R6 and R7, optocouplers U2 and U3, voltage-dividing resistors R8, R9, R10 and R11, P-type MOS tubes Q1 and Q3, and a BMS control circuit, and the BMS control circuit includes relays K1 and K2, N-type MOS tubes Q2 and Q4, and pull-down resistors R12 and R13; The moving contact of relay K1 is electrically connected to the positive output terminal of the battery pack of the explosion-proof quick-change power supply box through the maintenance switch K of the explosion-proof quick-change power supply box, the static contact of relay K1 is electrically connected to the high-voltage positive contact DC+ of the explosion-proof quick-change power supply box, the negative terminal of the relay K1 coil is electrically connected to the No. 3 pin of the N-type MOS tube Q2, the No. 1 pin of the N-type MOS tube Q2, the control signal BMS_ctr1 output terminal of the BMS and one end of the pull-down resistor R12 have a common contact, the No. 2 pin of the N-type MOS tube Q2 and the other end of the pull-down resistor R12 are electrically connected to the negative pole of the 24V power output terminal of the switching power supply, and the relay K1 coil The positive terminal of the optocoupler U2 is electrically connected to the No. 3 pin of the P-type MOS tube Q1, the No. 2 pin of the P-type MOS tube Q1 and one end of the voltage-dividing resistor R8 are both electrically connected to the positive electrode of the 24V power output terminal, the No. 1 pin of the P-type MOS tube Q1, the other end of the voltage-dividing resistor R8 and one end of the voltage-dividing resistor R9 have a common contact, the other end of the voltage-dividing resistor R9 is electrically connected to the No. 4 pin of the optocoupler U2, and the No. 3 pin of the optocoupler U2 is electrically connected to the negative electrode of the 24V power output terminal of the switching power supply; the No. 1 pin of the optocoupler U2 is connected to the DC12V power output terminal of the power conversion module, and the No. 2 pin of the optocoupler U2 is connected to the output terminal of the control signal Ctr1 of the voltage comparison module through the current-limiting resistor R6; The moving contact of relay K2 is electrically connected to the negative output terminal of the battery pack, the static contact of relay K2 is electrically connected to the high-voltage negative contact DC- of the explosion-proof quick-change power supply box, the negative terminal of the relay K2 coil is electrically connected to pin 3 of the N-type MOS tube Q4, pin 1 of the N-type MOS tube Q4, the output terminal of the control signal BMS_ctr2 of the BMS, and one end of the pull-down resistor R13 have a common contact, pin 2 of the N-type MOS tube Q4 and the other end of the pull-down resistor R13 are both electrically connected to the negative pole of the 24V power output terminal of the switching power supply, and the positive terminal of the relay K2 coil is electrically connected to the P-type MOS tube Q3 Pin 3 of the optocoupler U3 is electrically connected, pin 2 of the P-type MOS tube Q3 and one end of the voltage-dividing resistor R10 are both electrically connected to the positive electrode of the 24V power supply output terminal, pin 1 of the P-type MOS tube Q3, the other end of the voltage-dividing resistor R10 and one end of the voltage-dividing resistor R11 have a common contact, the other end of the voltage-dividing resistor R11 is electrically connected to pin 4 of the optocoupler U3, and pin 3 of the optocoupler U3 is electrically connected to the negative electrode of the 24V power supply output terminal of the switching power supply; pin 1 of the optocoupler U3 is connected to the DC12V power supply output terminal of the power conversion module, and pin 2 of the optocoupler U3 is connected to the control signal Ctr1 output terminal of the voltage comparison module through the current-limiting resistor R7.

6. The high and low voltage output control circuit of the coal mine explosion-proof quick-change power supply box according to claim 1 is characterized in that: The low voltage control module includes an optical coupler U4, an N-type MOS tube Q5, a relay K3 and a self-locking relay K4, a self-recovery button SW1, a current limiting resistor R14, and voltage dividing resistors R15 and R16; The moving contact of relay K3 and the positive terminal of the coil and one end of the voltage-dividing resistor R15 are all connected to the 24V power output end of the switching power supply. The stationary contact of relay K3 and the positive terminal of the coil of self-locking relay K4 are all electrically connected to the low-voltage contact A+ of the explosion-proof quick-change power supply box. The negative terminal of the coil of relay K3, one end of the self-recovery button SW1 and the moving contact of self-locking relay K4 have a common contact. The stationary contact of self-locking relay K4, the other end of the self-recovery button SW1 and pin 3 of N-type MOS tube Q5 have a common contact. Pins 1 and 2 of N-type MOS tube Q5 are connected to the positive terminal of the coil of relay K3 and the positive terminal of the coil of self-locking relay K4. One end of the voltage-dividing resistor R16 and pin 3 of the optocoupler U4 have a common contact, pin 4 of the optocoupler U4 is electrically connected to the other end of the voltage-dividing resistor R15, pin 2 of the N-type MOS tube Q5, the other end of the voltage-dividing resistor R16, the negative terminal of the coil of the self-locking relay K4, the low-voltage contact A- of the explosion-proof quick-change power supply box and the negative pole of the 24V power output terminal of the switching power supply have a common contact, pin 1 of the optocoupler U4 is connected to the positive pole of the DC12V power output terminal of the power conversion module, and pin 2 of the optocoupler U4 is connected to the control signal Ctr2 output terminal of the voltage comparison module through the current limiting resistor R14.

7. The high and low voltage output control circuit of the coal mine explosion-proof quick-change power supply box according to claim 1 is characterized in that: The CC2 mirror module includes optocouplers U5 and U6 and resistors R17, R18, and R19; pin 1 of the optocoupler U5 is connected to the positive pole of the DC12V power output terminal of the power conversion module, pin 2 of the optocoupler U5 is connected to the Ctr1 control signal output terminal of the voltage comparison module through resistor R17, pin 1 of the optocoupler U6 is connected to the Ctr2 control signal output terminal of the voltage comparison module through resistor R18, pin 2 of the optocoupler U6 is connected to the protective ground contact PE of the explosion-proof quick-change power box, pin 3 of the optocoupler U5 is connected to pin 4 of the optocoupler U6 through resistor R19, and pin 4 of the optocoupler U5 and pin 3 of the optocoupler U6 are electrically connected to the BMS to provide the BMS with a detection signal for detecting whether the charger plug is plugged into the socket of the explosion-proof quick-change power box.

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