Maximum power intrinsic safety charging control method and control circuit for coal mine underground intrinsic safety type inspection robot

Abstract

The invention relates to a maximum power intrinsic safety charging control method and control circuit for an underground coal mine intrinsic safety type inspection robot, and belongs to the technical field of mining inspection robot charging. The circuit comprises an anti-backflow module, a slow start module, an input power detection module, a single-chip microcomputer, a charging control module, a charging current detection module and a charging voltage detection module. The single-chip microcomputer receives an acquisition signal of the input power detection module, calculates the input power of the intrinsic safety power supply, and adjusts the output reference voltage when an intrinsic safety power supply protection mechanism is triggered. The charging control module outputs PWM pulse current according to the charging enable signal output by the single chip microcomputer, and controls the charging current of the battery pack according to the feedback of the charging voltage detection module and the charging current detection module; the charging current detection module detects charging current in real time, converts the charging current into a voltage signal, compares the voltage signal with reference voltage and feeds back a comparison result to the charging control module, so that the charging current is regulated and controlled, and it is ensured that charging power follows the maximum power of the intrinsically safe power supply.

Description

Technical Field

[0001] This invention belongs to the field of charging technology for mining inspection robots, and relates to a maximum power intrinsically safe charging control method and control circuit for an intrinsically safe inspection robot in underground coal mines. Background Technology

[0002] The underground environment in coal mines is dangerous and complex. Inspection robots can replace or assist manual labor in tasks such as monitoring equipment status and detecting environmental parameters (such as gas concentration and temperature), which is of great significance for ensuring safe production and reducing manpower while increasing efficiency. These robots are usually powered by batteries, and their battery life is a key factor limiting their long-term continuous operation.

[0003] Coal mines present explosive hazardous environments such as methane and coal dust, imposing strict explosion-proof requirements on electrical equipment. When intrinsically safe inspection robots are charged underground, the charging power supply must meet intrinsic safety requirements, meaning that its output electrical energy, under any possible fault condition, is insufficient to ignite a specified explosive mixture. This results in strict limitations on the output power of a single intrinsically safe power supply.

[0004] Currently, directly charging robot batteries using intrinsically safe power supplies suffers from low charging efficiency. Traditional constant current (CC) or constant voltage (CV) charging strategies fail to fully utilize the maximum permissible power of the intrinsically safe power supply. In the initial charging phase when the battery voltage is low, even if the charging current reaches the maximum permissible value of the intrinsically safe power supply, the actual charging power (P = Vbat * Ichg) is still far below the power supply's maximum output power capability because the battery voltage is significantly lower than the power supply's maximum output voltage. As the battery voltage increases, in the later stages of charging, the charging current must decrease to avoid exceeding the maximum output voltage limit of the intrinsically safe power supply, again resulting in the actual charging power being lower than the maximum permissible value. This makes the entire charging process excessively time-consuming, severely impacting the effective working time of the inspection robot.

[0005] To address the issue of low charging efficiency of robot batteries, existing technologies have proposed some solutions, such as connecting multiple intrinsically safe power supplies in series to increase output voltage / power, or charging control strategies based on parameters such as temperature and state of charge. However, existing technologies lack specific solutions on how to dynamically adjust the charging current while ensuring intrinsically safe performance, so that the intrinsically safe power supply always operates near its maximum rated output power throughout the entire charging cycle, thereby minimizing charging time. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a method and control circuit for charging an intrinsically safe power supply to an intrinsically safe inspection robot in coal mines, thereby solving the problems of low charging efficiency and long charging time of inspection robots in existing technologies while meeting the intrinsic safety requirements of underground coal mines. This invention significantly shortens charging time and improves the working efficiency and online rate of the inspection robot by dynamically optimizing the charging current and fully utilizing the maximum allowable power output of the intrinsically safe power supply.

[0007] To achieve the above objectives, the first aspect of the present invention provides a maximum power intrinsically safe charging control circuit connected between an intrinsically safe power supply and a battery pack of an inspection robot. The circuit includes an anti-backflow module, a soft-start module, an input power detection module, a microcontroller, a charging control module, a charging current detection module, and a charging voltage detection module.

[0008] The backflow prevention module is connected to the intrinsically safe power supply output terminal to prevent current backflow. The soft-start module is connected to the output terminal of the anti-backflow module to smoothly start the charging process; The input power detection module is connected to the output of the soft-start module to detect the input voltage and current of the intrinsically safe power supply in real time. The microcontroller is connected to the input power detection module, receives the acquisition signal from the input power detection module and calculates the input power of the intrinsically safe power supply, and adjusts the output reference voltage when the intrinsically safe power supply protection mechanism is triggered. The charging control module is connected to the microcontroller, outputs a charging current in the form of PWM pulses according to the charging enable signal output by the microcontroller, and controls the charging current of the battery pack according to the feedback from the charging voltage detection module and the charging current detection module. The charging current detection module is connected between the output of the charging control module and the battery pack. It detects the charging current in real time, converts the charging current into a voltage signal, compares it with a reference voltage, and then feeds the comparison result back to the charging control module. The charging voltage detection module is connected to the output of the charging control module, which detects the battery pack charging voltage in real time and feeds it back to the charging control module.

[0009] Furthermore, the anti-backflow module includes diodes D1 and D2 connected in series. The positive terminal of diode D1 is connected to an intrinsically safe power supply, and the negative terminal is connected to the positive terminal of diode D2. The negative terminal of diode D2 outputs electrical energy to the subsequent circuit.

[0010] Furthermore, the soft-start module includes capacitor C3, resistor R3, resistor R5, and PMOS transistor Q1; capacitor C3 and resistor R3 form an RC circuit, the first end of capacitor C3 is connected to the output terminal of the anti-backflow module, the second end of capacitor C3 is connected to the second end of resistor R3, the first end of resistor R3 is connected to the output terminal of the anti-backflow module, the second end of resistor R3 is connected to the first end of resistor R5, and the second end of resistor R5 is grounded; the source of PMOS transistor Q1 is connected to the output terminal of the anti-backflow module, the gate is connected to the first end of resistor R5, and the drain outputs power to subsequent circuits.

[0011] Furthermore, the charging current detection module includes a current sensing resistor R8, a current amplification chip U1, and operational amplifiers U2A and U2B. The current sensing resistor R8 is connected between the battery pack and ground. The Vin+ and Vin- pins of the current amplification chip U1 are connected to the two ends of the current sensing resistor R8, respectively, and the OUT pin is connected to the inverting input of the operational amplifier U2B through the operational amplifier U2A. The non-inverting input of the operational amplifier U2B receives the reference voltage Vref output by the microcontroller, and the output is connected to the charging control module through diode D4.

[0012] Furthermore, the two ends of the current sensing resistor R8 are respectively connected to the charging control module to feed back the voltage difference to the charging control module.

[0013] The second aspect of the present invention provides a maximum power intrinsically safe charging control method, which is applied to the maximum power intrinsically safe charging control circuit described in the first aspect. The method includes: connecting the intrinsically safe charging control circuit between the intrinsically safe power supply and the battery pack of the inspection robot, and initiating the charging process. The input voltage and input current of the intrinsically safe power supply are detected in real time by the input power detection module, and the detection signal is transmitted to the microcontroller. The microcontroller calculates the input power of the intrinsically safe power supply in real time based on the signal collected by the input power detection module. At the same time, when the intrinsically safe power supply triggers the protection mechanism, it records the charging current of the battery pack and reduces the reference voltage Vref. The charging control module outputs PWM pulses periodically based on the charging enable signal output by the microcontroller, and controls the charging current of the battery pack based on feedback from the charging voltage detection module and the charging current detection module. The charging current is detected in real time by the charging current detection module, the charging current is converted into a voltage signal and compared with the reference voltage Vref. The comparison result is fed back to the charging control module to regulate the charging current so that the charging power of the battery pack does not exceed the maximum power of the power supply. The charging voltage detection module detects the battery pack charging voltage in real time and feeds it back to the charging control module to regulate the charging current.

[0014] Furthermore, in the charging current detection module, the charging current flowing through the current sensing resistor R8 is converted into a voltage signal by the current amplification chip U1. The voltage signal is output to the inverting input terminal of the operational amplifier U2B via the operational amplifier U2A. After being compared with the reference voltage Vref at the non-inverting input terminal of the operational amplifier U2B, the signal is output to the charging control module to regulate the charging current.

[0015] In addition, the two ends of the current sensing resistor R8 can be directly connected to the charging control module to feed back the voltage across the two ends to the charging control module. The charging control module then compares the voltage difference across the current sensing resistor R8 with the preset threshold voltage and controls the PWM pulse output based on the comparison result.

[0016] The beneficial effects of this invention are as follows: 1) This invention monitors the input power of the intrinsically safe power supply in real time and dynamically adjusts the charging current, so that the intrinsically safe power supply always works near the maximum allowable power output point throughout the entire charging cycle. This avoids the problem of insufficient charging power caused by battery voltage changes in traditional constant current or constant voltage charging strategies, thereby fully tapping the potential of the intrinsically safe power supply, effectively improving energy utilization efficiency, significantly reducing the charging time of the inspection robot, and improving its recovery speed.

[0017] 2) The control circuit is designed with multiple safety protection mechanisms, including an anti-backflow module to prevent reverse current flow, a soft-start module to smooth the starting current and avoid instantaneous impact, and dual-path charging current detection and regulation. Even if the microcontroller experiences a program failure, the charging control module can still limit the charging current in real time through the hardware path to prevent the battery pack from overcharging or short-circuiting, strictly meeting the intrinsic safety requirements of the explosive environment in underground coal mines, and improving the overall stability and accident prevention capabilities of the system.

[0018] 3) This invention uses a microcontroller to calculate the maximum output power of the intrinsically safe power supply in real time and adjusts the reference voltage accordingly to precisely control the charging current, ensuring that the battery pack charging power always follows the maximum power output of the intrinsically safe power supply. This dynamic optimization mechanism ensures full utilization of power resources, avoids overload risks, maintains the stability and continuity of the charging process, and improves the adaptability and efficiency of the charging strategy.

[0019] 4) The control circuit proposed in this invention adopts a modular structure, with universal components and a reasonable layout, making it easy to integrate into existing inspection robot systems without the need for complex external equipment, thus reducing the complexity of installation and maintenance.

[0020] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the maximum power intrinsically safe charging control circuit for an intrinsically safe inspection robot in an underground coal mine, provided in an embodiment of the present invention. Figure 2 for Figure 1 The schematic diagram of the circuit structure shown is shown. Detailed Implementation

[0022] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0023] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0024] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0025] Example 1 To address the issues of low charging efficiency and long charging time for inspection robots in existing technologies while meeting the intrinsic safety requirements of underground coal mines, this embodiment provides a maximum power intrinsically safe charging control circuit. By dynamically optimizing the charging current, it fully utilizes the maximum allowable power output of the intrinsically safe power supply, significantly shortening the charging time and improving the working efficiency and online rate of the inspection robot.

[0026] like Figure 1 As shown, this embodiment provides a maximum power intrinsically safe charging control circuit, which includes an anti-backflow module, a soft-start module, an input power detection module, a microcontroller, a charging control module, a charging current detection module, and a charging voltage detection module.

[0027] The intrinsically safe power input, after passing through the anti-backflow module and the soft-start module, controls the current of the inspection robot's battery pack during the charging process through the charging control module to achieve constant current charging. During the charging process, the input power detection module detects the power input provided by the intrinsically safe power supply in real time and transmits it to the microcontroller. The microcontroller triggers an action according to the protection mechanism of the intrinsically safe power supply. When the protection mechanism is triggered, the microcontroller adjusts the reference voltage Vref. At the same time, the microcontroller also provides a charging enable signal to the charging control module, thereby enabling the charging control module to periodically output PWM pulses to charge the robot's battery pack in a PWM pulse manner.

[0028] In addition, during the charging process, the charging current detection module and the charging voltage detection module detect the charging current and charging voltage of the battery pack in real time, and simultaneously feed them back to the charging control module so that the charging control module can control the charging current.

[0029] The charging current detection module feeds back to the charging control module via two paths. One path feeds back the voltage across a current-sensing resistor to the charging control module, controlling the charging current based on the voltage difference between the two ends compared to a preset threshold voltage. The other path uses a current amplifier chip to collect the charging current flowing through the current-sensing resistor, converts it into a voltage signal, inputs it to the input of an operational amplifier, compares it with a reference voltage Vref output by the microcontroller, and then transmits the operational amplifier's output signal to the charging control module. The reference voltage Vref is adjusted and reduced when the intrinsically safe power supply protection mechanism is triggered; that is, when the battery pack charging power exceeds the intrinsically safe power supply input power, the reference voltage is lowered to regulate the battery pack charging current, thus ensuring the battery pack charging power follows the intrinsically safe power supply input power and improving charging efficiency. By using these two paths to detect and regulate the charging current, the charging control circuit can still control the charging current even in the event of a microcontroller program failure, preventing uncontrolled battery charging and potential safety accidents.

[0030] Example 2 like Figure 2 The diagram shows the specific circuit structure of the maximum power intrinsically safe charging control circuit provided in this embodiment.

[0031] The backflow prevention module includes diodes D1 and D2 connected in series. The positive terminal of diode D1 is connected to an intrinsically safe power supply, and the negative terminal is connected to the positive terminal of diode D2. The negative terminal of diode D2 outputs electrical energy to the subsequent circuit.

[0032] The soft-start circuit includes capacitor C3, resistors R3 and R5, and PMOS transistor Q1. Capacitor C3 and resistor R3 form an RC circuit. Utilizing the charging and discharging characteristics of the RC circuit, the gate-source voltage (Vgs) of PMOS transistor Q1 is controlled to rise slowly, thus allowing the MOS transistor to turn on slowly. This achieves a gradual increase in output voltage and current, preventing the intrinsically safe power supply from instantaneously charging the large capacitor in the circuit, providing overcurrent protection. Specifically, the first terminal of resistor R3 is connected to the negative terminal of diode D2, and the second terminal of R3 is connected to the first terminal of resistor R5; the first terminal of capacitor C3 is connected to the negative terminal of diode D2, and the second terminal of C3 is connected to the first terminal of resistor R5; the second terminal of resistor R5 is grounded; the source of PMOS transistor Q1 is connected to the negative terminal of diode D2, the gate is connected to the first terminal of resistor R5, and the drain is connected to the subsequent circuitry.

[0033] The input power detection module includes resistors R1 and R6, and a Hall current sensor SR1. The Hall current sensor SR1 detects the intrinsically safe power supply input current. Resistors R1 and R6 form a voltage detection circuit, with a voltage detection point between R1 and R6 used to detect the intrinsically safe power supply input voltage. Specifically, resistors R1 and R6 are connected in series and then in parallel between the intrinsically safe power supply and ground. The Hall current sensor SR1 is connected to the drain of the PMOS transistor Q1.

[0034] After receiving the current and voltage detection signals from the input power detection module, the microcontroller calculates the input power of the intrinsically safe power supply. Simultaneously, the microcontroller also generates a charging enable signal, causing the charging control module to periodically output PWM pulses to charge the robot's battery pack, facilitating control of the charging current.

[0035] The charging control module includes capacitor C4, power management chip U3, inductor L1, capacitors C1 and C2, resistor R2, capacitor C5, and fuse FU1. Resistor R2 serves as an enable control resistor; its first end is connected to the drain of PMOS transistor Q1 and the VIN pin of chip U3, and its second end is connected to the enable signal output of the microcontroller and the UVLO pin of chip U3. Inductor L1 is connected to the SW1 and SW2 pins of power management chip U3, serving as an energy storage element for storing and transferring energy. Capacitor C1 has its first end connected to the BOOT1 pin of chip U3 and its second end connected to the first end of inductor L1. Capacitor C2 has its first end connected to the BOOT2 pin of chip U3 and its second end connected to the second end of inductor L1. Capacitors C1 and C2 are bootstrap capacitors, providing power storage for the internal MOS switches, thus ensuring the normal operation of power management chip U3. One end of capacitor C4 is connected to the VIN pin of chip U3, and the other end is grounded. One end of capacitor C5 is connected to the VOUT pin of chip U3, and the other end is grounded. Capacitors C4 and C5 can regulate the input and output voltage. One end of fuse FU1 is connected to the VOUT pin of chip U3, and the other end is connected to the battery pack. Fuse FU1 can protect the battery pack in case of a fault in the charging circuit, preventing large current from flowing through and damaging the battery pack.

[0036] The charging voltage detection module includes resistors R4 and R7. R4 and R7 are connected in series and then connected in parallel between the VOUT pin of chip U3 and ground. A connection point is taken between R4 and R7, which is connected to the FB pin of chip U3 and the battery voltage detection port of the microcontroller.

[0037] The charging current detection module includes resistors R8, R9, R10, and R11, capacitors C6 and C7, diode D4, current amplifier chip U1, and operational amplifier. Resistor R8 serves as the current sensing resistor, connected between the robot battery pack and ground. Both ends of resistor R8 are connected to the ISP and ISN pins of chip U3, respectively. The Vin+ and Vin- pins of current amplifier chip U1 (INA138 in this embodiment) are connected to both ends of resistor R8, the V+ pin is connected to the power supply VCC, the GND pin is grounded, and the OUT pin is connected to operational amplifier U2A. One end of resistor R10 is connected to the OUT pin of chip U1, and the other end is grounded. Operational amplifier U2A, resistor R11, and capacitor C7 form a filter network. The non-inverting input of operational amplifier U2A is connected to the OUT pin of chip U1. Resistor R11 and capacitor C7 are connected in parallel between the output and inverting input of operational amplifier U2A. The output of operational amplifier U2A is connected to the inverting input of operational amplifier U2A. Resistor R9 and capacitor C6 form a filter circuit that filters the reference voltage Vref output by the microcontroller before outputting it to the non-inverting input of U2B. The output of operational amplifier U2B is connected to the FB pin of chip U3 through diode D4.

[0038] Example 3 Based on the specific circuit structure of the maximum power intrinsically safe charging control circuit described in Embodiment 2, this embodiment provides a charging control method, as follows: After connecting the intrinsically safe charging control circuit between the intrinsically safe power supply and the robot's battery pack, the battery pack begins charging. During this process, the microcontroller, chip U3, charging current detection module, charging voltage detection module, and input power detection module operate in real time.

[0039] Chip U3 detects the charging current in real time through two paths. One path involves chip U3's ISP and ISN pins acquiring the voltage across resistor R8, calculating the voltage difference, and comparing it in real time with a preset threshold voltage. When the voltage difference reaches or exceeds the threshold voltage, chip U3 immediately terminates the current cycle's PWM output pulse, effectively turning off the internal switching transistor to achieve pulse-by-pulse current limiting and regulate the charging current. The other path involves chip U1 converting the current flowing through resistor R8 into a voltage, which is then output to the non-inverting input of operational amplifier U2A via its OUT pin. The voltage output from its OUT pin is... , The charging current flowing through resistor R8, and the voltage The voltage is obtained after passing through a filter network (composed of operational amplifier U2A, resistor R11, and capacitor C7). , The input is given to the inverting input of operational amplifier U2B and compared with the reference voltage Vref at the non-inverting input. When Vref > When the U2B outputs a high level to the FB pin of chip U3, the FB pin is set to a high level, thus temporarily shutting down the charging output of chip U3. Both paths jointly regulate the charging current. In the event of a microcontroller program failure, the intrinsically safe charging control circuit can also achieve regulation through the ISP and ISN pins, improving the safety redundancy of the charging process.

[0040] The microcontroller calculates the input power of the intrinsically safe power supply in real time based on the signals acquired by the input power detection module. The microcontroller adjusts its output voltage Vref. Specifically, the maximum power output of the intrinsically safe power supply decreases as the operating time increases. When the robot's battery pack charging power exceeds the maximum power of the intrinsically safe power supply, i.e., when the intrinsically safe power supply triggers its protection mechanism, the output voltage of the intrinsically safe power supply is zero, and the microcontroller records the battery charging current at this time. At the same time, the Vref value is reduced. Because the Vref value is reduced, the voltage required for the operational amplifier U2B to output a high level next time is reduced. It will also decrease, so the allowable charging current will be reduced. Comparison Decrease By making these continuous adjustments, the charging power can be adjusted to match the output power of the intrinsically safe power supply, thereby ensuring that the intrinsically safe power supply always operates near its maximum power output point and shortening battery charging time.

[0041] In summary, this invention proposes a method and circuit for controlling the maximum power intrinsically safe charging of an intrinsically safe inspection robot in coal mines. By employing a microcontroller to monitor the maximum power of the intrinsically safe power supply in real time and adjusting the microcontroller's output reference voltage, the charging current at the robot's battery pack is limited. This ensures that the battery pack's power never exceeds the maximum power of the intrinsically safe power supply, meaning that the battery pack's power follows the maximum power of the intrinsically safe power supply during charging. This ensures that the intrinsically safe power supply always operates near its maximum power output point, shortening battery charging time. Furthermore, the control circuit includes voltage and current detection circuits. By detecting the charging voltage and current of the battery pack in real time and comparing them with preset thresholds in the power management chip, the current output of the power management chip is controlled, regulating the charging current and thus collaboratively ensuring that the battery pack's charging power follows the maximum power of the intrinsically safe power supply.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A maximum power intrinsically safe charging control circuit, connected between an intrinsically safe power supply and the battery pack of an inspection robot, characterized in that, It includes an anti-backflow module, a soft-start module, an input power detection module, a microcontroller, a charging control module, a charging current detection module, and a charging voltage detection module; The backflow prevention module is connected to the intrinsically safe power supply output terminal to prevent current backflow. The soft-start module is connected to the output terminal of the anti-backflow module to smoothly start the charging process; The input power detection module is connected to the output of the soft-start module to detect the input voltage and current of the intrinsically safe power supply in real time. The microcontroller is connected to the input power detection module, receives the acquisition signal from the input power detection module and calculates the input power of the intrinsically safe power supply, and adjusts the output reference voltage when the intrinsically safe power supply protection mechanism is triggered. The charging control module is connected to the microcontroller, outputs a charging current in the form of PWM pulses according to the charging enable signal output by the microcontroller, and controls the charging current of the battery pack according to the feedback from the charging voltage detection module and the charging current detection module. The charging current detection module is connected between the output of the charging control module and the battery pack. It detects the charging current in real time, converts the charging current into a voltage signal, compares it with a reference voltage, and then feeds the comparison result back to the charging control module. The charging voltage detection module is connected to the output of the charging control module, which detects the battery pack charging voltage in real time and feeds it back to the charging control module.

2. The maximum power intrinsically safe charging control circuit according to claim 1, characterized in that, The backflow prevention module includes diodes D1 and D2 connected in series. The positive terminal of diode D1 is connected to an intrinsically safe power supply, and the negative terminal is connected to the positive terminal of diode D2. The negative terminal of diode D2 outputs electrical energy to the subsequent circuit.

3. The maximum power intrinsically safe charging control circuit according to claim 1, characterized in that, The soft-start module includes capacitor C3, resistor R3, resistor R5, and PMOS transistor Q1. Capacitor C3 and resistor R3 form an RC circuit. The first end of capacitor C3 is connected to the output terminal of the anti-backflow module, and the second end is connected to the second end of resistor R3. The first end of resistor R3 is connected to the output terminal of the anti-backflow module, and the second end of resistor R3 is connected to the first end of resistor R5. The second end of resistor R5 is grounded. The source of PMOS transistor Q1 is connected to the output terminal of the anti-backflow module, the gate is connected to the first end of resistor R5, and the drain outputs power to subsequent circuits.

4. The maximum power intrinsically safe charging control circuit according to claim 1, characterized in that, The charging current detection module includes a current sensing resistor R8, a current amplification chip U1, and operational amplifiers U2A and U2B. The current sensing resistor R8 is connected between the battery pack and ground. The Vin+ and Vin- pins of the current amplification chip U1 are connected to the two ends of the current sensing resistor R8, respectively. The OUT pin is connected to the inverting input of the operational amplifier U2B through the operational amplifier U2A. The non-inverting input of the operational amplifier U2B receives the reference voltage Vref output by the microcontroller, and the output is connected to the charging control module through diode D4.

5. The maximum power intrinsically safe charging control circuit according to claim 4, characterized in that, The two ends of the current sensing resistor R8 are connected to the charging control module to provide feedback of the voltage difference to the charging control module.

6. A maximum power intrinsically safe charging control method, applied to the maximum power intrinsically safe charging control circuit according to any one of claims 1 to 5, characterized in that, The method includes: connecting the intrinsically safe charging control circuit between the intrinsically safe power supply and the battery pack of the inspection robot to initiate the charging process; The input voltage and input current of the intrinsically safe power supply are detected in real time by the input power detection module, and the detection signal is transmitted to the microcontroller. The microcontroller calculates the input power of the intrinsically safe power supply in real time based on the signal collected by the input power detection module. At the same time, when the intrinsically safe power supply triggers the protection mechanism, it records the charging current of the battery pack and reduces the reference voltage Vref. The charging control module outputs PWM pulses periodically based on the charging enable signal output by the microcontroller, and controls the charging current of the battery pack based on feedback from the charging voltage detection module and the charging current detection module. The charging current is detected in real time by the charging current detection module, the charging current is converted into a voltage signal and compared with the reference voltage Vref. The comparison result is fed back to the charging control module to regulate the charging current so that the charging power of the battery pack does not exceed the maximum power of the power supply. The charging voltage detection module detects the battery pack charging voltage in real time and feeds it back to the charging control module to regulate the charging current.

7. The maximum power intrinsically safe charging control method according to claim 6, characterized in that, In the charging current detection module, the charging current flowing through the current sensing resistor R8 is converted into a voltage signal by the current amplification chip U1. The voltage signal is output to the inverting input terminal of the operational amplifier U2B via the operational amplifier U2A. After being compared with the reference voltage Vref at the non-inverting input terminal of the operational amplifier U2B, the signal is output to the charging control module to regulate the charging current.

8. The maximum power intrinsically safe charging control method according to claim 7, characterized in that, The two ends of the current sensing resistor R8 are directly connected to the charging control module. The charging control module compares the voltage difference across the current resistor R8 with a preset threshold voltage and controls the PWM pulse output based on the comparison result.

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