Mining self-adaptive constant air volume control method without sensor detection and air supply device

Abstract

The invention relates to a mining self-adaptive constant-air-volume control air supply device without sensor detection, which is characterized by comprising a main machine rear cover (2), a fan rear cover (4), a fan (3), a filter device (110) and a main machine front cover (1) which are sequentially connected together, a vibration motor (6) and an electric control board (8) are arranged on two sides of the fan (3), and the filter device (110) is arranged on the main machine front cover (1). The fan (3), the electric control board (7) and the vibration motor (6) are fixed in an internal space set by the main machine front cover (1) through screws; the LED light guide plate (5) is mounted at the top of the fan (3), and a display control plate (8) is further mounted on the LED light guide plate (5); a battery box cover (15), a lithium battery (16) and a battery box (14) are sequentially mounted at the bottom of the fan (3) downwards; a charging interface is formed in the side surface of the battery box (14); due to the design of high filtration, miniaturization, light weight and portability, the equipment is suitable for being worn by individual protection equipment, and is convenient and practical.

Description

Technical Field

[0001] The present invention relates to the technical field of mining safety equipment, particularly a sensorless, adaptive constant air volume control method and air supply device for mining. This device is primarily used for individual protection of underground workers. By intelligently regulating air volume, it ensures that miners can breathe sufficient and fresh air in the harsh underground environment, safeguarding their lives. Technical Background

[0002] In underground mining environments like coal mines, miners must wear specialized protective gear to ensure their safety due to the presence of hazardous gases and substances such as gas and dust. Powered ventilation products are a crucial component of miners' personal protective equipment. They are secured to the miner's waist via a belt, filter the underground air through a filtration system, and then, through the rotation of a fan, deliver the filtered air into the miner's hood, providing a clean breathing environment.

[0003] However, as the filter material clogs, air flow gradually decreases, impacting not only miners' breathing comfort but also potentially reducing their work efficiency and even threatening their lives. Traditionally, underground workers rely on half-masks or ordinary filter masks for passive breathing, which can cause facial discomfort and even allergic reactions, making them inadequate for the complex and ever-changing working environment.

[0004] Furthermore, due to the unique operating environments, mining powered ventilation products place extremely high demands on performance and safety. First, all components must possess excellent flame retardancy and anti-static properties to prevent fires or explosions caused by electrical failures. Second, all electrical components and assemblies must pass mandatory explosion-proof safety certification to ensure safe and stable operation in the harsh underground environment. Finally, since miners often wear and move around for extended periods, ventilation systems must be miniaturized and integrated to reduce their workload and improve work efficiency.

[0005] To address these issues, the present invention proposes a sensorless adaptive constant air volume control method and air supply device for mining. This method utilizes sensorless technology to detect parameters such as three-phase current to determine the blockage of the filter material and adjust the fan speed in real time to maintain a constant air volume. This product accurately adjusts the air volume in real time based on the blockage of the filter material, without any contact with the face. Furthermore, the device incorporates a series of advanced technical measures to ensure safe and stable operation in the complex environment of underground mines, providing miners with a continuous, clean breathing environment. Summary of the Invention

[0006] A sensorless mine-use adaptive constant air volume control air supply device, characterized in that it includes a main unit rear cover 2, a fan rear cover 4, a fan 3, a filter device 110, and a main unit front cover 1 connected together in sequence, wherein a vibration motor 6 and an electric control board 8 are on both sides of the fan 3, and the fan 3, the electric control board 7, and the vibration motor 6 are fixed to the internal space defined by the main unit front cover 1 by screws; an LED light guide plate 5 is mounted on the top of the fan 3, and a display control board 8 is also mounted on the LED light guide plate 5; a battery box cover 15, a lithium battery 16, and a battery box 14 are sequentially mounted downward from the bottom of the fan 3; a charging port is provided on the side of the battery box 14;

[0007] The electronic control board 7 includes an input module, a central control module, an output module, a current acquisition module, a motor drive module, a vibration motor drive module, a buzzer drive module and an LED drive module; wherein the input module, the output module, the current acquisition module, the motor drive module, the vibration motor drive module, the buzzer drive module and the LED drive module are respectively connected to the central control module.

[0008] The filtering device 110 includes a filter box 13, a primary filter cotton 12 and a metal filter screen 11; the charging interface on the side of the battery box 14 is provided with a waterproof and dustproof sealing plug.

[0009] The display and control board 8 is provided with a display and control LED; and a light-transmitting soft board 10 is sealed and mounted on the display and control board 8 .

[0010] The central control module collects the three-phase working current signal of the fan motor in real time through the current acquisition module, and the motor drive module obtains a smooth current through modulation; the vibration motor drive module turns on vibration at a high level and turns off vibration at a low level; the buzzer drive module is mainly used for reminders and alarms.

[0011] The current acquisition module amplifies and acquires the three-phase current through the GS8634-TR low-noise operational amplifier. Specifically:

[0012] 1) Use Hall current sensor to collect the three-phase working current of the fan motor in real time;

[0013] 2) Configure signal conditioning circuit, including filtering, amplification and AD conversion units;

[0014] 3) Communicate data with the main control chip through the SPI interface;

[0015] 4) Establish the current-air volume characteristic model: I = k × Q 2 +b, where Q is the air volume, k and b are the operating coefficients.

[0016] The motor drive module receives the output signal of the main chip and obtains a high-quality smooth current through a three-phase current acquisition algorithm. Specifically:

[0017] 1) IGBT-based three-phase inverter circuit, including overcurrent protection and soft start unit;

[0018] 2) Receive the PWM speed regulation signal output by the main control chip, where the frequency range is 0-5kHz;

[0019] 3) Realize stepless adjustment of fan speed, and the speed can be adjusted between 0-10000rpm;

[0020] 4) Configure hardware watchdog circuit to ensure drive safety.

[0021] The vibration motor driving module is controlled by outputting high and low levels through the main chip GPIO. A high level turns on vibration, and a low level turns off vibration.

[0022] The buzzer driver module is mainly used for reminders and alarms. The main working states are: when the system is in the shutdown state, long press the power button for 2 seconds and the buzzer will beep; when the system is in the normal working state of the power on state, long press the power button for 2 seconds and the buzzer will beep for a long time to remind the system is shutting down;

[0023] The LED driver module controls the on / off of four battery indicator LEDs and three system congestion LEDs via GPIO outputs. The four battery indicator LEDs indicate battery voltage levels: if only one illuminates, the battery voltage is low and needs to be recharged; if all four illuminate, the battery is nearly fully charged. The three system congestion LEDs indicate the severity of system congestion: if only one illuminates, the system can operate normally with minimal congestion; if all three illuminate, the system is severely congested and requires filter replacement.

[0024] The method for controlling air volume by using the sensorless mine-used adaptive constant air volume control air supply device is characterized in that:

[0025] Step S1: real-time acquisition of the three-phase operating current signal of the brushless DC motor;

[0026] Step S2: Dynamically suppressing noise on the current signal using a Kalman filter algorithm;

[0027] Step S3: Establish a current-air volume mapping model: I = k·Q 2 +b, where Q is the air volume, I is the current value, k and b are the operating coefficients;

[0028] Step S4: adopting a cascade PID controller, wherein: the speed loop transfer function is Gc1(s)=Kp1+Ki1 / s+Kd1s;

[0029] Where G_{c1}(s) is the transfer function of the speed loop controller, s is a complex frequency domain variable, K_{p1} is the speed loop proportional gain coefficient, K_{i1} is the speed loop integral gain coefficient, and K_{d1} is the speed loop differential gain coefficient;

[0030] The current loop transfer function is Gc2(s)=Kp2+Ki2 / s

[0031] Where G_{c2}(s) is the current loop controller transfer function, K_{p2} is the current loop proportional gain coefficient, and K_{i2} is the current loop integral gain coefficient;

[0032] Step S5: When the detected current characteristic value exceeds the threshold, the vibration motor and the LED graded alarm are activated;

[0033] Step S6: adjusting the PWM duty cycle through the IGBT drive module to achieve speed compensation.

[0034] Technical problems to be solved by the present invention

[0035] 1. It solves the problems of rapid filtration efficiency degradation and poor air supply stability of traditional oxygen supply equipment in complex underground working conditions. Through the synergistic effect of the multi-stage composite filtration mechanism and the adaptive compensation system, it maintains a continuous filtration efficiency of more than 99.9% in the mine environment with dynamically changing dust concentration, ensuring the breathing safety of deep mining workers.

[0036] 2. Break through the technical limitations of traditional air volume control devices that rely on physical sensors, establish a sensorless detection model based on operating condition characteristic parameters, and through real-time perception of human metabolic needs and equipment operating status, realize dynamic air volume compensation of the air supply system under multiple disturbance conditions such as personnel movement, changes in labor intensity, and gradual filter clogging, and control the air supply volume fluctuation within ±3%.

[0037] 3. To overcome the response hysteresis defect of existing mining respiratory protection equipment under abnormal working conditions, a multi-parameter coupled intelligent diagnostic algorithm is constructed. When a sudden surge in dust concentration or abnormal airflow disturbance is detected, the air supply mode can be switched within 200ms, and the linkage mechanism of the backup filter unit can be triggered simultaneously to form multiple safety protections.

[0038] 4. This system addresses the risk of secondary contamination caused by untimely filter element replacement in traditional constant air volume devices. By analyzing the dynamic patterns of airflow characteristic parameters, it predicts the risk of filter component failure in advance and reminds miners of the replacement progress through a display panel, buzzer, and vibration motor.

[0039] 5. The present invention is designed according to the mandatory requirements for fans, batteries, and circuit boards in GB3836.4 to meet the Class I explosion-proof standards for mining.

[0040] 6. The sensorless air volume adaptive control algorithm used in this invention is based on the phase current parameters of the brushless DC motor. The airflow state is inferred by real-time acquisition of the motor current and voltage parameters. A fuzzy PID controller is also introduced to establish a three-dimensional mapping relationship table between pressure difference, flow rate and speed, achieving dynamic compensation for ±3% air volume deviation.

[0041] 7. This invention implements a low-power intelligent management strategy, namely, a respiratory rhythm prediction model based on the Kalman filter algorithm, dynamically adjusting the air supply volume (adjustable from 30-200 L / min), reducing power consumption by 40%, and allowing continuous operation for more than 17 hours;

[0042] 8. The device of the present invention can be used in explosion-proof environments in mines. Unlike existing materials, the device housing is made of flame-retardant and anti-static materials, which meets mining standards.

[0043] 9. This invention is the first to use sensor-free adaptive constant air volume control technology, which not only helps reduce the weight of the main unit, but also saves costs and reduces system power consumption, making it easier to pass underground mine safety inspections.

[0044] 10. The present invention is designed to have high filtration, miniaturization, lightness and portability, so the equipment is suitable for wearing as personal protective equipment, which is convenient and practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 , block diagram of the cascade PID control system of the present invention;

[0046] Figure 2 , workflow diagram of the present invention;

[0047] Figure 3 , the vibration alarm working process diagram of the present invention;

[0048] Figure 4 , the blockage alarm workflow of the present invention;

[0049] Figure 5 , electrical connection block diagram of the system of the present invention;

[0050] Figure 6 , schematic diagram of fan speed following conditions with different blockage ratios using the adaptive algorithm of the present invention;

[0051] Figure 7 , a schematic diagram of the control architecture of the present invention;

[0052] Figure 8 , main unit structure diagram of the air supply device of the present invention;

[0053] Figure 9 , main unit structure diagram of the air supply device of the present invention.

[0054] Among them, 1 is the front cover of the main unit, 2 is the back cover of the main unit, 3 is the fan, 4 is the back cover of the fan (the front cover of the fan and the back cover of the main unit are designed as one body, so they are not shown), 5 is the LED light guide plate, 6 is the vibration motor, 7 is the electric control board, 8 is the display control board, 9 is the display control board LED, 10 is the light-transmitting soft board, 11 is the metal filter, 12 is the primary filter cotton, 13 is the filter box, 14 is the battery box, 15 is the battery box cover, 16 is the lithium battery, 17 is the charging port, 18 is the waterproof and dustproof sealing plug, and 110 is the filtering device. DETAILED DESCRIPTION

[0055] A sensorless mine adaptive constant air volume control method, characterized by comprising:

[0056] Step S1: real-time acquisition of the three-phase operating current signal of the brushless DC motor;

[0057] Step S2: Dynamically suppressing noise on the current signal using a Kalman filter algorithm;

[0058] Step S3: Establish a current-air volume mapping model: I = k·Q 2 +b, where Q is the air volume, I is the current value, k and b are the operating coefficients;

[0059] Step S4: adopting a cascade PID controller, wherein: the speed loop transfer function is Gc1(s)=Kp1+Ki1 / s+Kd1s;

[0060] The current loop transfer function is Gc2(s)=Kp2+Ki2 / s;

[0061] Step S5: When the detected current characteristic value exceeds the threshold, the vibration motor and the LED graded alarm are activated;

[0062] Step S6: adjusting the PWM duty cycle through the IGBT drive module to achieve speed compensation.

[0063] The overall structure of the host of the present invention includes three major components: the host, the air supply duct and the helmet. The air outlet of the host is connected to the ventilation duct through a rotary bayonet, and the other end of the ventilation duct is connected to the helmet through a quick-release interface.

[0064] The present invention provides a sensorless, adaptive constant air volume control method and air supply device for mining. This control method requires no additional sensors or diagnostic devices, boasts a simple structure and assembly, and can achieve constant air volume control under various operating conditions. In the event of a system failure, accurate judgment and corresponding response strategies can be implemented, effectively reducing failure rates and maintenance costs.

[0065] The host structure includes: 1 is the host front cover, 2 is the host rear cover, 3 is the fan, 4 is the fan rear cover (the fan front cover and the host rear cover are designed as an integrated whole and are therefore not shown), 5 is the LED light guide plate, 6 is the vibration motor, 7 is the electric control board, 8 is the display control board, 9 is the display control board LED, 10 is the light-transmitting soft board, 11 is the metal filter, 12 is the primary filter cotton, 13 is the filter box, 14 is the battery box, 15 is the battery box cover, 16 is the lithium battery, 17 is the charging interface, and 18 is the waterproof and dustproof sealing plug.

[0066] Next, we'll explain the connection and assembly relationships of all the structural components, especially those related to the electrical components. To reduce the overall weight of the main unit, an innovative design embeds the fan rear cover 4 within the main unit rear cover 2, creating an integrated design. The fan 3 is inserted through the main unit front cover 1 and secured with three self-tapping screws. The assembled main unit front cover 1 is then assembled with the fan rear cover 4 and secured with self-tapping screws. On one side of the fan 3 is the electrical control board 7, which is tightened and secured through the reserved threaded holes in the main unit rear cover 2. The fan's 8-pin electrical interface is inserted into the electrical control board 7, completing the hardware connection of the fan 3. On the other side of the fan 3 is the vibration motor 6, which is secured through the reserved base in the main unit rear cover 2. Above it is the display control board 8, which is integrated by placing the LED light guide plate 5 onto the display control board 8 and clamped in place by the main unit front cover 1 and rear cover 2. The control button cables, LED control cables, fan control cables, and vibration motor 6 control cables on the display control board 8 are all reliably connected to the electrical control board 7 via the electrical interface on the control board 7.

[0067] The air supply duct is made of a pleated flexible material, and the rubber cover at the interface is completely isolated from the outside air. By plugging and tightening, it can be reliably connected to the main blower outlet and quickly assembled and disassembled.

[0068] Quick installation and removal with the helmet interface can be achieved by pressing.

[0069] The helmet is not the main content of this patent, and it only explains that the interface with the ventilation hose is a quick-release interface.

[0070] The control method of the present invention is studied in the host computer, wherein the main components involved in the control method include: electric control board, fan, battery, buzzer, vibration motor, and LED.

[0071] The electric control board includes a current acquisition module, a motor drive module, a vibration motor drive module, a buzzer drive module, an LED drive module and the like.

[0072] The current acquisition module amplifies and acquires the three-phase current through the GS8634-TR low-noise operational amplifier.

[0073] 1) Use Hall current sensor to collect the three-phase working current of the fan motor in real time;

[0074] 2) Configure signal conditioning circuit (including filtering, amplification, and AD conversion units);

[0075] 3) Communicate data with the main control chip through the SPI interface;

[0076] 4) Innovative establishment of current-air volume characteristic model: I = k × Q 2 +b (Q is the air volume, k and b are the operating coefficients);

[0077] The motor drive module receives the output signal of the main chip and obtains a high-quality smooth current through a three-phase current acquisition algorithm. Specifically:

[0078] 1) IGBT-based three-phase inverter circuit (including overcurrent protection and soft start unit);

[0079] 2) Receive the PWM speed regulation signal (frequency range 0-5kHz) output by the main control chip;

[0080] 3) Realize stepless adjustment of fan speed (0-10000rpm);

[0081] 4) Configure hardware watchdog circuit to ensure drive safety;

[0082] The vibration motor driver module is controlled by the main chip GPIO output high and low levels. A high level turns on vibration, and a low level turns off vibration. The vibration motor in the product mainly works when the battery voltage is extremely low (less than 10.5V).

[0083] The buzzer driver module is mainly used for reminders and alarms. The main working states are: when the system is in the shutdown state, long press the power button for 2 seconds and the buzzer will beep; when the system is in the normal working state of the power on state, long press the power button for 2 seconds and the buzzer will beep for a long time to remind the system is shutting down;

[0084] The LED driver module controls the on / off of four battery indicator LEDs and three system congestion LEDs via GPIO outputs. The four battery indicator LEDs indicate battery voltage levels: if only one illuminates, the battery voltage is low and needs to be recharged; if all four illuminate, the battery is nearly fully charged. The three system congestion LEDs indicate the severity of system congestion: if only one illuminates, the system can operate normally with minimal congestion; if all three illuminate, the system is severely congested and requires filter replacement.

[0085] The main control process of the present invention is as follows: long pressing the external control hardware button to start the fan, slowly starting and gradually reaching the rated speed; the electronic control board starts to detect system parameters in real time to determine whether there is an abnormality; if an abnormality occurs, the type of abnormality is determined and corresponding processing is performed.

[0086] The system is turned on by long pressing the only control button on the host for 2 seconds. Under the power-on condition, the shutdown is also achieved by long pressing the only control button on the host for 2 seconds. The speed regulation is achieved by short pressing (less than 1 second) the only control button on the host to achieve continuous switching. When in the power-on state, short press the button and the system switches to high windshield, and the high windshield LED light lights up. Regardless of high windshield or low windshield, the system has an adaptive air volume adjustment function. After startup, the blockage status will be detected. The blockage status is divided into 3 levels, indicating that the blockage intensity is getting higher and higher. The system will adaptively increase or decrease the air supply according to the blockage situation, and the blockage LED light will light up. If there is no blockage, the 3 LED lights are off. The more serious the blockage, the more blockage LEDs will light up. The maximum is level 3 blockage. If the blockage is at level 3 for a long time, the system will emit intermittent beeps.

[0087] The external control hardware button is the only control button on the host. Its hardware is connected to the I / O pin of the microcontroller on the electronic control board. Its function is mainly to control the system startup, shutdown and speed regulation.

[0088] Adaptive control is one such control method. The mainframe system incorporates two control methods: active speed control and passive speed control. Adaptive control is the active type. Active speed control uses an internal algorithm to calculate the required speed and current using system parameters acquired by the electronic control board. Passive speed control is achieved by long-pressing a single hardware button on the mainframe. The fan is then driven by speed control commands output by the microcontroller I / O pins on the electronic control board.

[0089] The fan is driven by a brushless DC outer rotor motor, offering high efficiency, low noise, and a long lifespan. The blades are made of lightweight, flame-retardant, and anti-static ABS material, with a small radius and low moment of inertia. The blades and impeller are angled in a well-designed manner, ensuring high airflow and low noise. Even if the fan becomes clogged, the flow rate is not significantly affected.

[0090] The switching mode between the two control modes is: if there is no passive button pressing for a long time (more than 5s), the system will automatically take over and switch to active control (adaptive control); or if there is serious external congestion, it will also actively switch to active control.

[0091] The core of adaptive control lies in the implementation of the control algorithm. A Kalman filter dynamically estimates and predicts current data, combined with a first-order low-pass filter and a sliding mean filter to suppress and smooth noise. Based on the processed current data, the fan speed adjustment is calculated using either a PID control algorithm or a fuzzy control algorithm. This system utilizes a cascaded PID control principle to achieve adaptive control.

[0092] Gc2(s) is the current loop transfer function, Gc1(s) is the speed loop transfer function, and the speed loop output control variable u1 serves as the current loop reference variable R2(s). Synchronous control is used, meaning the speed loop and current loop have the same sampling control period.

[0093] The main advantages of cascade control:

[0094] (1) Add interference to the current loop and suppress it by controlling the current loop.

[0095] (2) The changes in the parameters in the current loop are controlled by the current loop, and the impact on the controlled object Gc1 is greatly reduced.

[0096] (3) The inertia of the current loop is adjusted by the current loop, thereby improving the response speed of the entire system.

[0097] Establish a current-air volume quadratic function model: air volume Q and current I satisfy I=k·Q 2 +b mapping relationship, where:

[0098] I: Real-time collected motor operating current (unit: A)

[0099] Q: Output air volume (unit: m 3 / min)

[0100] k: Fan load characteristic coefficient (calibrated through wind tunnel tests or empirical values)

[0101] b: System no-load current reference value (calibrated by zero flow condition)

[0102] Note: In line with the square torque characteristics of the fan, the current is proportional to the square of the air volume. When the filter is clogged:

[0103] At constant speed, Q↓→load torque decreases→I↓, at this time, the speed needs to be increased to compensate for the air volume→I↑

[0104] 2. The speed loop transfer function is Gc1(s)=Kp1+Ki1 / s+Kd1s. The following is the symbol definition table

[0105]

[0106] 3. Current loop transfer function Gc2(s) = Kp2 + Ki2 / s. The following symbol definition table:

[0107] symbol Physical meaning unit Control function description G_{c2}(s) Current loop controller transfer function - Inner loop controller, receiving current error signal K_{p2} Current loop proportional gain coefficient - Quick response to current fluctuations K_{i2} Current loop integral gain coefficient <![CDATA[s -1 ]]> Ensure current tracking accuracy

Claims

1. A sensorless mine-use adaptive constant air volume control air supply device, characterized in that: The invention comprises a main unit rear cover (2), a fan rear cover (4), a fan (3), a filter device (110) and a main unit front cover (1) which are connected in sequence, wherein a vibration motor (6) and an electric control board (8) are located on both sides of the fan (3), and the fan (3), the electric control board (7) and the vibration motor (6) are fixed in an internal space defined by the main unit front cover (1) by screws; an LED light guide plate (5) is installed on the top of the fan (3), and a display control board (8) is also installed on the LED light guide plate (5); a battery box cover (15), a lithium battery (16) and a battery box (14) are installed downwardly from the bottom of the fan (3); a charging interface is provided on the side of the battery box (14); The electric control board (7) comprises an input module, a central control module, an output module, a current acquisition module, a motor drive module, a vibration motor drive module, a buzzer drive module and an LED drive module; wherein the input module, the output module, the current acquisition module, the motor drive module, the vibration motor drive module, the buzzer drive module and the LED drive module are respectively connected to the central control module.

2. A sensorless mine-use adaptive constant air volume control air supply device according to claim 1, characterized in that: The filtering device (110) comprises a filter box (13), primary filter cotton (12) and a metal filter screen (11); a waterproof and dustproof sealing plug is provided on the charging interface on the side of the battery box (14).

3. The sensorless detection mine-used adaptive constant air volume control air supply device according to claim 1, characterized in that: The display and control board (8) is provided with a display and control LED; and a light-transmitting soft board (10) is sealed and mounted on the display and control board (8).

4. The sensorless detection mine-used adaptive constant air volume control air supply device according to claim 1, characterized in that: The central control module collects the three-phase working current signal of the fan motor in real time through the current acquisition module, and the motor drive module obtains a smooth current through modulation; the vibration motor drive module turns on vibration at a high level and turns off vibration at a low level; the buzzer drive module is mainly used for reminders and alarms.

5. The sensorless detection mine-used adaptive constant air volume control air supply device according to claim 1, characterized in that: The current acquisition module amplifies and acquires the three-phase current through the GS8634-TR low-noise operational amplifier. Specifically: 1) Use Hall current sensor to collect the three-phase working current of the fan motor in real time; 2) Configure signal conditioning circuit, including filtering, amplification and AD conversion units; 3) Communicate data with the main control chip through the SPI interface; 4) Establish the current-air volume characteristic model: I = k × Q 2 +b, where Q is the air volume, k and b are the operating coefficients.

6. The sensorless detection mine-used adaptive constant air volume control air supply device according to claim 1, characterized in that: The motor drive module receives the output signal of the main chip and obtains a high-quality smooth current through a three-phase current acquisition algorithm. Specifically: 1) IGBT-based three-phase inverter circuit, including overcurrent protection and soft start unit; 2) Receive the PWM speed regulation signal output by the main control chip, where the frequency range is 0-5kHz; 3) Realize stepless adjustment of fan speed, and the speed can be adjusted between 0-10000rpm; 4) Configure hardware watchdog circuit to ensure drive safety.

7. The sensorless detection mine-used adaptive constant air volume control air supply device according to claim 1, characterized in that: The vibration motor driving module is controlled by outputting high and low levels through the main chip GPIO. A high level turns on vibration, and a low level turns off vibration.

8. The sensorless detection mine-used adaptive constant air volume control air supply device according to claim 1, characterized in that: The buzzer driver module is mainly used for reminders and alarms. The main working states are: when the system is in the shutdown state, the buzzer will beep after long pressing the power button for 2 seconds; when the system is in the normal working state of power on, long pressing the power button for 2 seconds, the buzzer will emit a long beep to remind the system is shutting down.

9. The sensorless detection mine-used adaptive constant air volume control air supply device according to claim 1, characterized in that: The LED driver module controls the on / off of four battery indicator LEDs and three system congestion LEDs via GPIO outputs. The four battery indicator LEDs indicate battery voltage levels: if only one illuminates, the battery voltage is low and needs to be recharged; if all four illuminate, the battery is nearly fully charged. The three system congestion LEDs indicate the severity of system congestion: if only one illuminates, the system can operate normally with minimal congestion; if all three illuminate, the system is severely congested and requires filter replacement.

10. A method for controlling air volume using the sensorless mine-use adaptive constant air volume control air supply device according to claim 1, characterized in that: Step S1: real-time acquisition of the three-phase operating current signal of the brushless DC motor; Step S2: Dynamically suppressing noise on the current signal using a Kalman filter algorithm; Step S3: Establish a current-air volume mapping model: I = k·Q 2 +b, where Q is the air volume, I is the current value, k and b are the operating coefficients; Step S4: adopting a cascade PID controller, wherein: the speed loop transfer function is Gc1(s)=Kp1+Ki1 / s+Kd1s; Where G_{c1}(s) is the transfer function of the speed loop controller, s is a complex frequency domain variable, K_{p1} is the speed loop proportional gain coefficient, K_{i 1} is the speed loop integral gain coefficient, and K_{d1} is the speed loop differential gain coefficient; The current loop transfer function is Gc2(s)=Kp2+Ki2 / s Where G_{c2}(s) is the current loop controller transfer function, K_{p2} is the current loop proportional gain coefficient, and K_{i2} is the current loop integral gain coefficient; Step S5: When the detected current characteristic value exceeds the threshold, the vibration motor and the LED graded alarm are activated; Step S6: adjusting the PWM duty cycle through the IGBT drive module to achieve speed compensation.

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