Ventilator blower pressure lift control method and apparatus

Abstract

The ventilator fan pressure lifting control method comprises the following steps: S301: establishing a multiple fitting formula of a pressure correction value of a patient end according to a leakage amount; S302: reading a temperature and humidity pressure and a differential pressure flow sensor value, and compensating and correcting the flow; S303: identifying a breathing switching state; S304: performing pressure lifting control in an inhalation state; and S305: performing pressure lowering control in an exhalation state. The ventilator fan pressure lifting control device comprises a fan control module, a temperature and humidity pressure sensor, a safety valve, a pressure sensor, a differential pressure sensor, a leakage module and an air path. The method and the device mainly avoid the situation that the original inhalation is converted into exhalation by inertia rotation, the pressure rising time is slow when the exhalation is switched into the inhalation state, and the airflow overshoot phenomenon may occur in the breathing switching process.

Description

Method and device for controlling the booster and depressurization of the ventilator fan Technical Field

[0001] This invention relates to the field of medical devices and control methods for medical devices, specifically to a method and apparatus for controlling the booster and depressurization of a ventilator fan. Background Technology

[0002] A ventilator is used to replace, control, or modify spontaneous breathing movements. This mechanical device establishes a pressure difference between the external environment and the lungs, thereby enhancing the patient's breathing and reducing the load on the respiratory muscles. When the patient has the ability to breathe spontaneously, the ventilator does less work than the patient; in this case, the ventilator provides assisted ventilation. A key indicator for evaluating the effectiveness of this mode is patient-ventilator synchrony. Patient-ventilator synchrony reflects the degree of matching between the patient and the ventilator during the transition between inspiratory and expiratory states. Asynchrony between the patient and the ventilator can lead to prolonged mechanical ventilation time, reduced patient comfort, and an increased risk of diaphragmatic muscle injury.

[0003] Factors affecting the synchronicity of a ventilator include the clinical settings for assistive pressure, respiratory trigger sensitivity settings, and pressure control performance. These clinical settings or the pressure regulation of the ventilator are also affected by external interferences such as airway leakage, patient secretions, and airway obstruction.

[0004] Pressure control is a key factor reflecting human-machine synchronization performance, and its regulation is particularly important. Existing technology (patent number 103977491A) discloses a method and device for improving CPAP comfort, which cuts off the power when transitioning from inhalation to exhalation to allow the motor to rotate due to inertia; and increases the motor speed when transitioning from exhalation to inhalation to allow the airway to reach a higher pressure suitable for inhalation.

[0005] The problems with the above-mentioned situation are: the inertial rotation is used when transitioning from inhalation to exhalation, and the large inertia of the motor makes the descent speed slow, which affects the exhalation process; the pressure rise time when switching from exhalation to inhalation is not fast enough; airflow overrush may occur during the breathing transition; and the existing technology does not consider the impact of external airway interference such as leakage or blockage, which increases the possibility of breathing asynchrony during patient use. Summary of the Invention

[0006] To overcome the shortcomings of the existing technology, this invention proposes a method and device for controlling the fan pressure rise and fall of a ventilator. By integrating external interference data of the airway, it better matches the patient's exhalation process during expiratory control and better matches the inspiratory pressure rise during inspiratory control, thus achieving a high degree of synchronization with the patient's breathing overall.

[0007] To achieve the above objectives, the present invention provides a method for controlling the pressure rise and fall of a ventilator fan, characterized by comprising the following steps:

[0008] S301: Establish a multinomial fitting formula for the pressure correction value at the patient end based on the amount of leakage at the mouth and nose mask end;

[0009] S302: Read the values ​​of temperature, humidity, pressure and differential pressure flow sensors, and perform flow compensation and calibration;

[0010] S303: Respiratory switching status recognition;

[0011] S304: Pressure boost control during inhalation;

[0012] S305: Controls blood pressure during exhalation;

[0013] S306: Judgment of monitoring pressure value being less than P_HighValue; when the monitored pressure value is less than P_HighValue, it indicates that the pressure is within the safe limit and the patient is comfortable, then proceed to step S307; otherwise, proceed to step S308;

[0014] S307, return to step S301: perform the cycle back and forth to periodically assist patient ventilation;

[0015] S308, safety valve leaks, alarm sounds and ventilator stops operating.

[0016] Furthermore, the formula for multinomial fitting is:

[0017] Pr = C1 * Q^3 + C2 * Q^2 + C3 * Q + C4

[0018] Wherein, C1, C2, C3, and C4 are the four coefficients obtained from the experiment, Q is the leakage value, and Pr is the pressure correction value at the patient end.

[0019] Furthermore, in S302, the compensation formula is:

[0020]

[0021] Where C1 is the water vapor density at T0℃ and P0 pressure, ρ0, T0, and P0 are the gas density, absolute temperature, and absolute pressure at T0℃ and P0 pressure, respectively, Z is the gas compressibility coefficient, ρ1, T1, and P1 are the gas density, absolute temperature, and absolute pressure at T1℃ and P1 pressure, respectively, F0 represents the flow rate before correction, and F1 represents the flow rate after correction.

[0022] In S303, the inhalation and exhalation trigger sensitivities are set to obtain the inhalation flow rate level Fin_TH and the exhalation flow rate level Fex_TH. The corrected flow rate F1 is subjected to moving average filtering to obtain the processed flow rate signal F1_Pre. When F1_Pre is greater than Fin_TH, it is determined that inhalation has started and the inhalation state is entered. When F1_Pre is less than Fex_TH, it is determined that exhalation has started and the exhalation state is entered.

[0023] Furthermore, S304 includes the following steps:

[0024] S3041: Reads the user-set ventilator boost time (Trise) and inspiratory pressure value (IPAP), corrects the set pressure to IPAP_Pr, and the corrected inspiratory pressure value (IPAP_Pr) is:

[0025] IPAP_Pr = IPAP + Pr;

[0026] S3042: Within time T1, based on the difference factor between the inspiratory pressure value IPAP and the expiratory pressure value EPAP, the fan performs acceleration control, and the acceleration method is as follows:

[0027] Blower_in=Blower_in+(p1E0 2 +p2E0+p3)*Kp*(E k -E k-1 )+(g1E0 2 +g2E0+g3)*Ki*E k t <T1,Blower_in<=Blower_in_TH

[0028] Wherein, Blower_in represents the fan input control voltage, which is initially zero and gradually accumulates within time T1, within the fan's input setting threshold Blower_in_TH, as the formula iterates; Kp is the proportional coefficient, Ki is the integral coefficient, p1, p2, p3 and g1, g2, g3 are constants, the difference factor between inspiratory pressure value IPAP and expiratory pressure value EPAP is E0, and the difference between the actual monitored airway pressure and the set pressure correction value IPAP_Pr is represented by E. k E k-1 It is expressed as the difference between the last actual monitored airway pressure value and the set pressure correction value IPAP_Pr. The selection of the T1 value depends on the set boost time Trise. As Trise decreases, T1 will increase.

[0029] S3043: During the Trip-T1 time period, based on the fan input value PWM_M calculated using the IPAP fitting model, the fan executes deceleration control to bring the pressure up to the set pressure correction value IPAP_Pr. The deceleration control method is as follows:

[0030] Blower_in=Blower_in+Kp2*(E k -E k-1 )+Ki2*E k Blower_in<=PWM_M+Th

[0031] Wherein, Blower_in represents the fan input control voltage, and the fan input control voltage at the initial moment is the fan input control voltage value at time T1 in S3042, Kp2 is the proportional coefficient, and Ki2 is the integral coefficient.

[0032] Furthermore, S305 includes the following steps:

[0033] S3051: Read the user-set ventilator depressurization time Tfall and expiratory pressure value EPAP, and correct the set pressure to EPAP_Pr: Expiratory pressure EPAP_Pr is corrected to: EPAP_Pr=EPAP+Pr.

[0034] S3052: During time T2, the fan performs first-stage deceleration control: First-stage deceleration control method: Applying a reverse fan input signal or opening the current dissipation resistor path enables the fan to achieve a faster descent speed. The form of the reverse fan input signal is:

[0035] Blower_in=A t *E0

[0036] Blower_in represents the wind turbine control input value that changes over time during time T2, A is a negative constant, and E0 is the difference factor between IPAP and EPAP.

[0037] S3053: Based on the fan input value PWM_N calculated using the IPAP fitting model, the fan executes two-stage deceleration control to bring the pressure up to the set pressure correction value EPAP_Pr: Fan input value PWM_N = f(EPAP_Pr), the two-stage deceleration method is as follows:

[0038] Blower_in=Blower_in+Kp3*(G k -G k-1 )+Ki3*G k Blower_in>=PWM_N-Th

[0039] Where Blower_in represents the fan input control voltage, which gradually decreases within the time interval Tfall-T2 and is greater than the fan input value PWM_N-Th, as the formula iterates. Th is the set threshold. The difference between the actual monitored airway pressure and the set pressure correction value EPAP_Pr is represented by G. k The difference between the last actual monitored airway pressure and the set pressure correction value EPAP_Pr is expressed as G. k-1 Kp3 is the proportional coefficient, and Ki3 is the integral coefficient.

[0040] The paper also proposes a fan pressure boosting control device, which includes a fan control module, a temperature, humidity and pressure sensor, a safety valve, a pressure sensor, a differential pressure sensor, a leakage module, and a gas path. The fan control module is electrically connected to the pressure sensor, differential pressure flow sensor, temperature, humidity and pressure sensor, safety valve, and leakage module. The fan control module, temperature, humidity and pressure sensor, safety valve, pressure sensor, differential pressure sensor, and leakage module are all connected to the gas path through pipelines.

[0041] Furthermore, the wind turbine control module consists of a power supply, a main controller, an overcurrent protection module, a bus current detection module, a PWM shaping module, a Hall effect detection and processing module, a wind turbine drive module, an H-bridge drive module, and a wind turbine. The power supply, overcurrent protection module, bus current detection module, PWM shaping module, and Hall effect detection and processing module are all electrically connected to the main controller. The wind turbine drive module is electrically connected to the PWM shaping module, bus current detection module, and H-bridge drive module. The wind turbine is electrically connected to the H-bridge drive module and the Hall effect detection and processing module.

[0042] Beneficial effects: By taking into account leakage, the pressure of the ventilator during the inspiratory and expiratory phases is adjusted to avoid the situation where inertial rotation is used when switching from inspiratory to expiratory, and the pressure rise time when switching from expiratory to inspiratory states is slow, which may cause airflow overrush during the breathing transition. Attached Figure Description

[0043] The invention will now be further described and explained with reference to the accompanying drawings.

[0044] Figure 1 is a flowchart of the fan pressure control method for a ventilator according to a preferred embodiment of the present invention;

[0045] Figure 2 is a schematic diagram of the fan pressure control device of the ventilator;

[0046] Figure 3 is a schematic diagram of the wind turbine control module.

[0047] Reference numerals: 1. Fan control module; 2. Temperature, humidity and pressure sensor; 4. Safety valve; 3. Pressure sensor; 7. Differential pressure sensor; 6. Leakage module; 5. Gas path; 100. Power supply; 101. Main controller; 102. Overcurrent protection module; 103. Bus current detection module; 104. PWM shaping module; 105. Hall effect detection and processing module; 106. Fan drive module; 107. H-bridge drive module; 108. Fan. Detailed Implementation

[0048] The technical solution of the present invention will be more clearly and completely explained below with reference to the accompanying drawings and through the description of preferred embodiments of the present invention.

[0049] As shown in Figure 1, the fan pressure control method for a ventilator according to the preferred embodiment of the present invention includes the following steps.

[0050] S301: Monitor the amount of leakage and use the amount of leakage to establish a multinomial fitting formula for the pressure correction value at the patient end.

[0051] Because the amount of leakage affects the final pressure delivered to the patient's nasal mask, pressure correction values ​​at the patient's end were recorded experimentally for different leakage amounts, and multiple fitting formulas were established:

[0052] Pr = C1 * Q^3 + C2 * Q^2 + C3 * Q + C4

[0053] Wherein, C1, C2, C3, and C4 are four constant coefficients obtained from the experiment, Q is the leakage amount, and Pr is the pressure correction value at the patient end.

[0054] S302: Reads the values ​​from the temperature, humidity, pressure, and differential pressure flow sensors, and performs flow compensation calibration. The compensation formula is:

[0055]

[0056] Where C1 is the water vapor density at T0℃ and P0 pressure, a known constant value; ρ0, T0, and P0 are the gas density, absolute temperature, and absolute pressure at T0℃ and P0 pressure, respectively, all constant values; H is the absolute humidity of the gas; and Z is the gas compressibility coefficient. Given the absolute temperature, absolute pressure, and gas density, the absolute humidity and gas compressibility coefficient can be calculated using existing formulas. ρ1, T1, and P1 are the gas density, absolute temperature, and absolute pressure at T1℃ and P1 pressure, respectively; F0 represents the flow rate before correction, and F1 represents the flow rate after correction.

[0057] S303: Recognition of breathing switching status.

[0058] The first step is to set the inspiratory and expiratory trigger sensitivity values ​​for the ventilator, namely the inspiratory flow rate level Fin_TH and the expiratory flow rate level Fex_TH, respectively.

[0059] The second step is to process the compensated gas flow rate F1 in the aforementioned ventilator tubing using an average filtering method to obtain the processed flow signal F1_Pre, and then compare F1_Pre with the inspiratory flow rate level Fin_TH and the expiratory flow rate level Fex_TH.

[0060] When F1_Pre is greater than Fin_TH, it is determined that inspiration has begun and the ventilator enters the inspiration state; when F1_Pre is less than Fex_TH, it is determined that expiration has begun and the ventilator enters the expiration state.

[0061] As can be seen from the above, the inhalation and exhalation states of the ventilator are controlled by the initial tracheal flow rate F0, and are directly controlled by the compensated tracheal flow rate F1.

[0062] S304: The ventilator determines that the patient is in an inspiratory state based on S303 and provides inspiratory pressure compensation to the patient, that is, the ventilator performs pressure control.

[0063] Specifically, this manifests in the following steps:

[0064] S3041: Read the ventilator boost time (Trise) and inspiratory pressure value (IPAP) set for the patient. Make a pressure correction based on the inspiratory pressure value (IPAP). The corrected inspiratory pressure is:

[0065] IPAP_Pr = IPAP + Pr

[0066] Where Pr is the pressure correction value described in S301. Therefore, the control of the ventilator's inspiratory pressure takes into account the amount of leakage at the patient end, so that the compensated inspiratory pressure value of the ventilator more closely matches the patient's original inspiratory pressure.

[0067] S3042: Within time T1, based on the difference factor between IPAP (inspiratory pressure) and EPAP (expiratory pressure), the fan performs acceleration control. The fan acceleration control adopts the following acceleration method:

[0068] Blower_in=Blower_in+(p1E0 2 +p2E0+p3)*Kp*(E k -E k-1 )+(g1E0 2 +g2E0+g3)*Ki*E k t <T1,Blower_in<=Blower_in_TH

[0069] Wherein, Blower_in represents the fan input control voltage, which is initially zero and gradually accumulates within time T1, within the fan's input setting threshold Blower_in_TH, as the formula iterates; Kp is the proportional coefficient, Ki is the integral coefficient, p1, p2, p3 and g1, g2, g3 are constant terms, the difference factor between IPAP and EPAP is represented by E0, and the difference between the actual monitored airway pressure and the set pressure correction value IPAP_Pr is represented by E... k E k-1 It is expressed as the difference between the last actual monitored airway pressure value and the set pressure correction value IPAP_Pr. The selection of the T1 value depends on the set boost time Trise. As Trise decreases, T1 will increase.

[0070] As can be seen from the above description, the acceleration control of the fan also incorporates the pressure correction value IPAP_Pr, which is calculated in conjunction with the leakage rate. Therefore, the overall acceleration control of the fan incorporates the leakage rate, which makes it more closely match the patient's inhalation state and more synchronized with the patient's inhalation pressure.

[0071] S3043: During the Trip-T1 time period, based on the fan input value PWM_M calculated by the IPAP fitting model, the fan executes deceleration control to make the pressure reach the set pressure correction value IPAP_Pr.

[0072] By combining experimental data, the relationship between the air path monitoring pressure and time under the PWM input of the fan was obtained. Multiple sets of relationship curves were obtained under different PWM experiments. By fitting these curves, a functional relationship could be established, yielding PWM_M = f(IPAP_Pr). Specifically, the deceleration / acceleration control method adopted is:

[0073] Blower_in=Blower_in+Kp2*(E k -E k-1 )+Ki2*E k t <Trise-T1,Blower_in<=PWM_M+Th

[0074] Wherein, Blower_in represents the fan input control voltage. At the initial moment, the fan input control voltage is the fan input control voltage value at time T1 in S3042. As the formula iterates, it will gradually accumulate within the time Trise-T1 and within the time less than the fan input value PWM_M+Th, where Th is the set threshold, Kp2 is the proportional coefficient, and Ki2 is the integral coefficient.

[0075] As shown in S3042 and S3043, the Trip time is divided into two segments: the first segment is within T1 time, and the second segment is within Trip-T1 time. The two segments use different fan acceleration methods. The purpose is twofold: first, the acceleration within T1 time can better match the inspiratory pressure requirements of the patient during breathing; second, the deceleration control within Trip-T1 time ensures that the end-inspiratory pressure reaches the set value smoothly and is used to meet the ventilator's expiratory control when the exhalation process arrives, avoiding possible airflow overrush during the breathing transition.

[0076] S305: The ventilator determines that the patient is in an expiratory state based on S303 and begins to lower blood pressure.

[0077] Specifically, this is manifested in the following steps.

[0078] S3051, Read the user-set ventilator depressurization time Tfall and expiratory pressure value EPAP, and correct the set pressure to EPAP_Pr: The corrected expiratory pressure is:

[0079] EPAP_Pr = EPAP + Pr.

[0080] The pressure correction for ventilator depressurization is similar to the pressurization process and is also controlled by leakage. Pr is the pressure correction value described in S301.

[0081] S3052: During time T2, the fan performs first-stage deceleration control. The first-stage deceleration control method involves applying a reverse fan input signal or opening the current dissipation resistor path, enabling the fan to achieve a faster descent speed. The form of the reverse fan input signal is as follows:

[0082] Blower_in=A t *E0,t <T2 Blower_in<PWM_M

[0083] Blower_in represents the wind turbine control input value that varies with time during time T2, and this value is less than PWM_M, where PWM_M = f(IPAP_Pr); A is a negative constant, and E0 is the difference factor between IPAP and EPAP.

[0084] S3053, during the time interval Tfall-T2, based on the fan input value PWM_N calculated using the IPAP fitting model, the fan executes two-stage deceleration control to bring the pressure up to the set pressure correction value EPAP_Pr. The fan input value PWM_N = f(EPAP_Pr), and the two-stage deceleration method is as follows:

[0085] Blower_in=Blower_in+Kp3*(G k -G k-1 )+Ki3*Gk t <Tfall-T2,

[0086] Blower_in>=PWM_N-Th

[0087] Where Blower_in represents the fan input control voltage, initially set to Blower_in(T2). As the formula iterates, this voltage gradually decreases within the time interval Tfall-T2, provided the fan input value is greater than PWM_N-Th. Here, Th is the set threshold, Kp3 is the proportional coefficient, and Ki3 is the integral coefficient. The difference between the actual monitored airway pressure and the set pressure correction value EPAP_Pr is represented by G. k The difference between the last actual monitored airway pressure and the set pressure correction value EPAP_Pr is expressed as G. k-1 .

[0088] As can be seen from the above description, during the expiratory phase of the ventilator, the present invention has two pressure adjustment methods: the first stage involves the fan slowing down in the reverse direction during the T2 time interval, which aims to enable the ventilator to quickly assist in exhaustion; the second stage involves decelerating exhaustion during the Tfall-T2 time interval, which aims to meet the inspiratory pressurization of the next stage, so that the ventilator can quickly pressurize after switching to the inspiratory state; it also helps to avoid airflow overshoot that may occur during the breathing switch.

[0089] Compared with the inertial method of pressurization and depressurization in existing ventilators, this invention uses leakage as a reference data and actively assists the ventilator in the exhalation process, making it easier to synchronize with the patient's breathing. It also provides two different pressurization stages during the inhalation phase, avoiding airflow overshoot caused by the switching of the breathing process.

[0090] S306: Judgment of monitoring pressure value less than P_HighValue. When the monitored pressure value is less than P_HighValue (maximum safe and comfortable pressure value), it indicates that the pressure is within the safe limit and within the range of patient comfort. In this case, proceed to step S307; otherwise, proceed to step S308.

[0091] S307, return to step S301. Perform the cycle back and forth to periodically assist patient ventilation.

[0092] S308, safety valve leaks, alarm sounds and ventilator stops operating.

[0093] The present invention also proposes a fan pressure control device for a ventilator, including a fan control module 1, a temperature, humidity and pressure sensor 2, a safety valve 4, a pressure sensor 3, a differential pressure sensor 7, a leakage module 6, and an air path 5; the fan control module 1, pressure sensor 3, differential pressure flow sensor, temperature, humidity and pressure sensor 2, safety valve 4, and leakage module 6 are all electrically connected, and the fan control module 1, temperature, humidity and pressure sensor 2, safety valve 4, pressure sensor 3, differential pressure sensor 7, and leakage module 6 are all connected to the air path 5 module via pipelines.

[0094] Temperature, humidity and pressure sensor 2 collects real-time environmental data from the air path module 5, including temperature, humidity and pressure. Specifically, it can be an integration of BME280, BMP280 or discrete temperature, humidity and pressure modules (MPL3150A2, SHT20).

[0095] The differential pressure flow sensor reads the pressure difference across the throttling device. The throttling device and the gas path 5 pipeline are connected in a bypass manner. The real-time flow rate in the gas path 5 is calculated through a fitting model of differential pressure and flow rate.

[0096] The data from temperature, humidity and pressure sensor 2 is used to compensate for the flow rate monitored in real time by the differential pressure flow sensor to obtain a more accurate flow rate value under actual working conditions.

[0097] Pressure sensor 3 reads the relative pressure value in the air path 5 in real time. This relative pressure value is further corrected by the monitoring value of leakage module 6. The corrected pressure truly reflects the pressure of the gas reaching the patient's mouth and nose mask end.

[0098] The leakage module 6 monitors the real-time leakage in the gas path 5. Specifically, it installs a flow monitoring unit at the end of the gas path 5, calculates the integral of the flow rate, and performs a difference calculation with the flow integral of the differential pressure flow sensor to obtain the leakage amount. The leakage amount and the real-time pressure are used to establish a multinomial fitting relationship. The fitting model is used to calculate the pressure value that the actual patient needs to increase or decrease.

[0099] Safety valve 4 has mechanical automatic venting and electromagnetic switch functions. When the pressure exceeds the threshold, the mechanical device will activate to divert the gas. When the pressure value monitored by the fan control module 1 is still greater than the threshold within a certain period of time, the electromagnetic switch valve will open, allowing the gas to be completely discharged from the outlet of safety valve 4.

[0100] The fan control module 1 consists of a power supply 100, a main controller 101, an overcurrent protection module 102, a bus current detection module 103, a PWM shaping module 104, a Hall detection and processing module 105, a fan drive module 106, an H-bridge drive module 107, and a fan 108.

[0101] The main controller 101 generates six complementary PWM signals. After interference signals are filtered out by the PWM shaping module 104, a clean PWM signal is obtained. This signal is then transformed by the timing control logic inside the fan drive module 106 and drives the MOSFETs in the H-bridge drive module 107 to turn on and off. The Hall effect detection processing module 105, installed inside the fan 108, detects the fan speed measurement signal. Based on the three-phase speed signal generated by the Hall sensor, the main controller locates the position of the rotor inside the fan 108 and drives the MOSFETs in the H-bridge drive module 107 to operate in the specified direction. The operating speed of the fan 108 is determined by the frequency of the 6-channel PWM generated inside the main controller 101; the bus current detection module 103 detects the total current flowing through the 3-phase windings of the fan and is used to suppress torque fluctuations of the fan 108; the overcurrent protection module 102 sets the current threshold by adjusting the resistance value. When the operating current of the fan 108 exceeds the set current threshold, the fan control module 1 is shut down, causing the fan to stop operating; the power supply module 100 supplies power to the entire system, meeting the different voltage and current requirements of the sensors, safety valve 4, and fan 108. The power supply module 100 is required to provide a large instantaneous current.

[0102] The above-described specific embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Various modifications, substitutions, and improvements made by those skilled in the art to the technical solutions of the present invention based on the provided textual description and drawings, without departing from the design concept and spirit of the present invention, should all fall within the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

Claims

1. A fan pressure control device for a ventilator, characterized in that, The device includes a fan control module, a temperature, humidity, and pressure sensor, a safety valve, a pressure sensor, a differential pressure sensor, a leakage module, and an air path. The fan control module, pressure sensor, differential pressure flow sensor, temperature, humidity, and pressure sensor, safety valve, and leakage module are all electrically connected. The fan control module, temperature, humidity, and pressure sensor, safety valve, pressure sensor, differential pressure sensor, and leakage module are all connected to the air path via pipelines. The control method for the fan pressure control device of the ventilator includes the following steps: S301: Establishing a multinomial fitting formula for the pressure correction value at the patient end based on the leakage amount at the oronasal mask end. The multinomial fitting formula is: Pr=C1*Q^3+C2*Q^2+C3*Q+C4, where C1, C2, C3, and C4 are four coefficients obtained experimentally, Q is the leakage amount, and Pr is the pressure correction value at the patient end; S302: Reading the values ​​of the temperature, humidity, and pressure sensor and the differential pressure flow sensor, and performing flow compensation correction. The compensation formula is: Where C1 is the water vapor density at T0℃ and P0 pressure, ρ0, T0, and P0 are the gas density, absolute temperature, and absolute pressure at T0℃ and P0 pressure, respectively, Z is the gas compressibility coefficient, ρ1, T1, and P1 are the gas density, absolute temperature, and absolute pressure at T1℃ and P1 pressure, respectively, F0 represents the flow rate before correction, and F1 represents the flow rate after correction; S303: Breathing switch state recognition, setting the inspiratory and expiratory trigger sensitivities, obtaining the inspiratory flow rate level Fin_TH and the expiratory flow rate level Fex_TH, performing moving average filtering on the corrected flow rate F1 to obtain the processed flow rate signal F1_Pre; when F1_Pre is greater than Fin_TH, it is determined that inspiration has started. The system enters the inspiratory state; when F1_Pre is less than Fex_TH, it is determined that expiration has begun and the system enters the expiratory state; S304: During the inspiratory state, pressure boosting control is performed, which includes the following steps: S3041: The user-set ventilator pressure boosting time Trise and inspiratory pressure value IPAP are read, and the set inspiratory pressure correction value is corrected to IPAP_Pr, wherein the set inspiratory pressure correction value IPAP_Pr is: IPAP_Pr = IPAP + Pr; S3042: During time T1, the fan performs acceleration control based on the difference factor between the inspiratory pressure value IPAP and the expiratory pressure value EPAP; S3043: During time Trise-T1, IPAP fitting is performed. The model calculates the fan input value PWM_M, and the fan performs deceleration control to make the pressure reach the set inspiratory pressure correction value IPAP_Pr; S305: During the expiratory state, pressure reduction control is performed, which includes the following steps: S3051: Read the user-set ventilator pressure reduction time Tfall and expiratory pressure value EPAP, and correct the set expiratory pressure correction value to EPAP_Pr: The set expiratory pressure correction value EPAP_Pr is corrected to: EPAP_Pr = EPAP + Pr; S3052: During time T2, the fan performs first-stage deceleration control: The first-stage deceleration control method is to apply a reverse fan input signal or open the current dissipation resistor path, so that the fan achieves A relatively fast descent rate; S3053: Based on the fan input value PWM_N calculated using the IPAP fitting model, the fan performs secondary deceleration control to bring the pressure up to the set expiratory pressure correction value EPAP_Pr: fan input value PWM_N = f(EPAP_Pr); S306: Judgment of monitoring pressure value less than P_HighValue; When the monitored pressure value is less than P_HighValue, it indicates that the pressure is within the safe limit and the patient is comfortable, and step S307 is executed; otherwise, step S308 is executed; S307: Return to step S301 to execute: perform the cycle back and forth to periodically assist patient ventilation; S308: Safety valve depressurizes, alarm is sounded and ventilator operation is stopped.

2. The fan pressure control device for a ventilator according to claim 1, characterized in that, S3042: The acceleration method is: Blower_in = Blower_in + (p1E0 2 + p2E0 + p3) * Kp * (E k - E k-1 ) + (g1E0 2 + g1E0 + g3) * Ki * E k When t < T1, Blower_in <= Blower_in_TH. Here, Blower_in represents the blower input control voltage. The initial blower input control voltage is zero. As the formula iterates, it will gradually accumulate within T1 time and less than the blower input set threshold Blower_in_TH. Kp is the proportionality coefficient, Ki is the integral coefficient, p1, p2, p3, and g1, g2, g3 are constant terms. The difference factor between the inspiratory pressure value IPAP and the expiratory pressure value EPAP is E0. The difference between the actual monitored airway pressure and the set inspiratory pressure correction value IPAP_Pr is represented as E k , E k-1 is represented as the difference between the previous actual monitored airway pressure value and the set inspiratory pressure correction value IPAP_Pr. The selection of the T1 value depends on the set pressure rise time Trise, and as Trise decreases, T1 will increase. S3043: The deceleration and acceleration control method is: Blower_in = Blower_in + Kp2 * (E k - E k-1 ) + Ki2 * E k , when t < Trise - T1, Blower_in <= PWM_M + Th. Here, Blower_in represents the blower input control voltage. The initial blower input control voltage is the blower input control voltage value at the T1 moment described in S3042. As the formula iterates, it will gradually accumulate within Trise - T1 time and less than the blower input value PWM_M + Th. Here, Th is the set threshold, Kp2 is the proportionality coefficient, and Ki2 is the integral coefficient.

3. The fan pressure control device for a ventilator according to claim 1, characterized in that, S3052: The form of the reverse blower input signal is: Blower_in = A t *E0, t < T2 Blower_in < PWM_M where Blower_in represents the blower control input value that changes with time within T2, and this value is less than PWM_M, where PWM_M = f(IPAP_Pr), A is a negative constant, and E0 is the difference factor between IPAP and EPAP; S3053: The secondary deceleration method is: Blower_in = Blower_in + Kp3*(G k -G k-1 ) + Ki3*G k , t < Tfall - T2 Blower_in >= PWM_N - Th where Blower_in represents the blower input control voltage. The initial blower input control voltage is Blower_in(T2). As the formula iterates, it will gradually decrease within the time of Tfall - T2 and be greater than the blower input value PWM_N - Th. Th is the set threshold, and the difference between the actual monitored airway pressure and the set expiratory pressure correction value EPAP_Pr is represented as G k , the difference between the previous actual monitored airway pressure and the set expiratory pressure correction value EPAP_Pr is represented as G k-1 , Kp3 is the proportionality coefficient, and Ki3 is the integral coefficient.

4. The fan pressure boosting control device according to claim 1, characterized in that, The fan control module consists of a power supply, a main controller, an overcurrent protection module, a bus current detection module, a PWM shaping module, a Hall effect detection and processing module, a fan drive module, an H-bridge drive module, and a fan. The power supply, overcurrent protection module, bus current detection module, PWM shaping module, and Hall effect detection and processing module are all electrically connected to the main controller. The fan drive module is electrically connected to the PWM shaping module, bus current detection module, and H-bridge drive module. The fan is electrically connected to the H-bridge drive module and the Hall effect detection and processing module.

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