Ventilation equipment closed loop control method in response to air quality data

Abstract

The present application relates to the field of ventilation control and environmental monitoring, in particular to a ventilation equipment closed-loop control method in response to air quality data, comprising: obtaining raw concentration data of air quality sensors in each region and calibrating the raw concentration data according to a sensitivity decay value to obtain a modified concentration; generating an initial air volume based on a pollution source equipment power supply loop current detection equipment start signal; distributing target air volumes of each region according to the modified concentration, target concentration requirements and total air volume limits; combining real-time wind speed and pipeline length to calculate gas diffusion lag time, pre-compensating the modified concentration and superimposing the initial air volume output variable frequency command through proportional integral adjustment; and performing abnormal detection and triggering safety protection according to wind speed deviation rate, sensor sensitivity decay value or comparator voltage signal during execution. The present application can take into account multi-region air volume distribution, sensor aging compensation and abnormal protection.

Description

Technical Field

[0001] This invention relates to the field of ventilation control and environmental monitoring, specifically to a closed-loop control method for ventilation equipment in response to air quality data. Background Technology

[0002] Currently, workshop ventilation control typically relies solely on real-time concentration feedback from air quality sensors for adjustment. This makes it difficult to promptly identify sensor aging, duct delivery delays, and transient exhaust demands when pollution sources are first activated, easily leading to control lag or unreasonable airflow distribution. At the same time, existing multi-zone ventilation systems often lack rapid protection mechanisms that work in conjunction with software control when actuators malfunction, sensors fail, or concentrations rise rapidly, making it difficult to ensure both air quality and system operational safety. Summary of the Invention

[0003] The purpose of this invention is to provide a closed-loop control method for ventilation equipment that responds to air quality data, shortens the control lag caused by sensor feedback lag, makes the feedback value closer to the pollution concentration in the air, can still take into account air quality requirements and fan operation control under the condition of limited total air volume, and still maintains controllable operation when the actuator or sensor is abnormal.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A closed-loop control method for ventilation equipment in response to air quality data is used in a multi-zone ventilation system. The multi-zone ventilation system includes multiple independent ventilation control zones. Each independent ventilation control zone is equipped with a pollution source device, an air quality sensor, a duct wind speed sensor, and a current detection module connected to the power supply circuit of the pollution source device. Each independent ventilation control zone also includes a fan and a fan frequency converter electrically connected to the fan.

[0006] The raw concentration data collected by the air quality sensors in the multiple independent ventilation control areas are acquired, and the raw concentration data is calibrated to obtain the corrected concentration.

[0007] Acquire the power supply circuit current data collected by the current detection module in each of the independent ventilation control areas; when the equipment start signal of the pollution source equipment is detected based on the power supply circuit current data, generate the initial air volume of the corresponding independent ventilation control area.

[0008] Based on the corrected concentration, the preset target concentration requirement, and the preset total air volume limit requirement, determine the target air volume for each of the independent ventilation control zones;

[0009] The system acquires real-time wind speed data for each independent ventilation control zone, determines the gas diffusion lag time based on the real-time wind speed data and preset duct length data, uses the gas diffusion lag time to pre-compensate the correction concentration, and outputs a fan frequency conversion command based on the pre-compensated correction concentration and the target air volume.

[0010] During the execution of the wind turbine frequency conversion command, anomaly detection is performed, a corresponding status flag is generated, and a safety protection action is triggered when an abnormal status is determined.

[0011] Preferably, calibrating the original concentration data to obtain the corrected concentration includes: acquiring original concentration data of a preset number of sampling points, extracting the real-time signal intensity corresponding to the original concentration data, determining the sensor sensitivity attenuation value based on the real-time signal intensity and a preset standard signal intensity; and generating a maintenance alarm data packet when the sensor sensitivity attenuation value is less than a preset aging threshold.

[0012] When the sensor sensitivity decay value is greater than or equal to the preset aging threshold, the original concentration data is compensated to obtain the corrected concentration.

[0013] Preferably, generating the initial air volume for the corresponding independent ventilation control zone includes: monitoring the power supply circuit current data in real time using a current detection module installed on the power supply circuit of the pollution source equipment as the equipment operating current;

[0014] When the device operating current is detected to be greater than or equal to a preset starting current threshold within a preset time window and the current peak value is within a preset peak range, the device start signal is determined to be active, and the initial air volume is determined according to the preset rated air volume parameters of the pollution source device; otherwise, the device start signal is determined to be inactive, and the initial air volume is set to zero.

[0015] Preferably, the target airflow for each of the independent ventilation control zones is determined based on the corrected concentration, the preset target concentration requirement, and the preset total airflow limit requirement, including:

[0016] Establish a mapping relationship between the power consumption and air volume of the fan driven by the fan inverter, allocate air volume based on the mapping relationship, the target concentration requirement and the total air volume limit requirement, output the target air volume of each independent ventilation control zone and set the lower limit corresponding to the target air volume;

[0017] When the device start signal is detected, the target air volume lower limit of the independent ventilation control area is adjusted to the initial air volume.

[0018] Preferably, the advance compensation includes: extracting historical correction concentrations and calculating the concentration change rate, combining the gas diffusion lag time with the concentration change rate to calculate an equivalent concentration value, and using the equivalent concentration value as the correction concentration after advance compensation.

[0019] Preferably, the anomaly detection includes: within a preset time period after the output of the fan frequency conversion command, acquiring real-time wind speed data through the duct wind speed sensor, and calculating the theoretical wind speed value based on the target air volume corresponding to the fan frequency conversion command and the preset duct cross-sectional area parameters.

[0020] Based on the real-time wind speed data and the theoretical wind speed value, the wind speed deviation rate is calculated;

[0021] When the wind speed deviation rate is greater than the preset maximum allowable deviation, a first state flag indicating a fault in the equipment is generated, and the independent ventilation control area is switched to the preset maximum airflow operation mode, and the target airflow for the independent ventilation control area is adjusted; when the wind speed deviation rate is less than or equal to the preset maximum allowable deviation, a second state flag indicating normal operation is generated.

[0022] Preferably, each of the independent ventilation control areas is equipped with two air quality sensors, and the anomaly detection further includes: obtaining the sensor sensitivity attenuation values ​​of the two air quality sensors in the same independent ventilation control area, and determining the consistency deviation based on the absolute value of the difference between the sensor sensitivity attenuation values ​​of the two air quality sensors;

[0023] When the consistency deviation is greater than the preset consistency threshold, the sensor sensitivity attenuation values ​​of the two air quality sensors are compared. The air quality sensor with the smaller sensor sensitivity attenuation value is identified as a failure node, and the status flag is updated. The sampling data of the failure node is removed in the subsequent closed-loop control adjustment.

[0024] When the consistency deviation is less than or equal to the preset consistency threshold, the air quality sensor is determined to be in normal consistency, and the current control mode is maintained.

[0025] When the sensor sensitivity decay values ​​of both air quality sensors are less than the preset aging threshold, the system switches to forced ventilation mode based on the device start signal and limits the target air volume of the independent ventilation control area to the preset upper limit value.

[0026] Preferably, the air quality sensor includes a signal output terminal, and the anomaly detection further includes: acquiring a voltage signal by a comparator circuit connected in parallel with the signal output terminal;

[0027] When the voltage signal exceeds the preset voltage safety threshold, a voltage over-limit anomaly is determined. Within a predetermined response time, a hardware relay electrically connected to the comparator circuit triggers all fans in the multi-zone ventilation system driven by the fan frequency converter to switch to the preset maximum airflow operation mode, and generates an emergency alarm message as a status marker.

[0028] When the voltage signal is less than or equal to the preset voltage safety threshold, maintain the current normal status flag.

[0029] The beneficial effects of this invention are:

[0030] 1. This invention allocates target air volume to each area by combining the corrected concentration, target concentration requirements and total air volume limit requirements, and adjusts the lower limit of target air volume to the initial air volume when the equipment start signal is activated. This can take into account the air quality control of multiple areas and the allocation of system resources under the condition of limited total air volume, and avoid unreasonable air volume and insufficient exhaust due to average allocation or local underestimation.

[0031] 2. This invention calculates the gas diffusion lag time based on real-time wind speed data and pipeline length data, and adjusts the correction concentration in advance in the time dimension. This allows the control input to be corrected to a level closer to the arrival state of the pollutants, reducing the impact of delivery delay on the adjustment results and improving the timeliness and stability of closed-loop control.

[0032] 3. After outputting the frequency conversion command of the fan, the present invention performs execution verification by the deviation rate between the wind speed and the theoretical wind speed, and performs anomaly detection by combining the sensor sensitivity attenuation value and the voltage signal output by the comparator circuit. It can simultaneously identify different risks such as actuator abnormality, sensor failure and rapid increase in concentration, forming a multi-level status marking and protection mechanism, and improving the system's ability to identify abnormal operating conditions. Attached Figure Description

[0033] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0034] Figure 1 This is a flowchart of the closed-loop control method for ventilation equipment in response to air quality data according to the present invention. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Please see Figure 1 This embodiment is applicable to workshop ventilation systems with multiple independent ventilation control zones; each independent ventilation control zone is equipped with pollution source equipment, air quality sensors, duct wind speed sensors, and a current detection module connected to the power supply circuit of the pollution source equipment, and each independent ventilation control zone is equipped with a fan and a fan frequency converter electrically connected to the fan.

[0037] The sensor sensitivity decay value is the ratio of the current signal quality of the air quality sensor to the signal quality in the initial calibration state;

[0038] The corrected concentration is the original concentration data after sensor aging compensation; the initial air volume is the preset basic exhaust volume applied to the corresponding area when the equipment start signal of the detected pollution source device is activated.

[0039] A closed-loop control method for ventilation equipment in response to air quality data, used in multi-zone ventilation systems, including:

[0040] The system acquires raw concentration data from air quality sensors in multiple independent ventilation control areas and calibrates the raw concentration data to obtain corrected concentrations.

[0041] Acquire the power supply circuit current data collected by the current detection module in each independent ventilation control area. When the equipment start signal of the pollution source equipment is detected based on the power supply circuit current data, the initial air volume of the corresponding independent ventilation control area is generated.

[0042] The target air volume for each independent ventilation control zone is determined based on the corrected concentration, the preset target concentration requirements, and the preset total air volume limit requirements.

[0043] The system acquires real-time wind speed data for each independent ventilation control zone, determines the gas diffusion lag time based on the real-time wind speed data and preset duct length data, uses the gas diffusion lag time to pre-compensate the correction concentration, and outputs fan frequency conversion commands based on the pre-compensated correction concentration and target air volume.

[0044] During the execution of wind turbine frequency conversion commands, anomaly detection is performed, corresponding status flags are generated, and safety protection actions are triggered when an abnormal status is determined.

[0045] The original concentration data is calibrated to obtain the corrected concentration, including: acquiring the original concentration data of a preset number of sampling points, extracting the real-time signal intensity corresponding to the original concentration data, and determining the sensor sensitivity attenuation value based on the real-time signal intensity and the preset standard signal intensity.

[0046] When the sensor sensitivity decay value is less than the preset aging threshold, a maintenance alarm data packet is generated; when the sensor sensitivity decay value is greater than or equal to the preset aging threshold, the original concentration data is compensated to obtain the corrected concentration.

[0047] The initial air volume for the corresponding independent ventilation control zone is generated by: real-time monitoring of the power supply circuit current data as the equipment operating current through a current detection module installed on the power supply circuit of the pollution source equipment;

[0048] When the device operating current is detected to be greater than or equal to the preset starting current threshold within a preset time window and the current peak value is within a preset peak range, the device start signal is determined to be active, and the initial air volume is determined according to the preset rated air volume parameters of the pollution source device; otherwise, the device start signal is determined to be inactive, and the initial air volume is set to zero.

[0049] During each control cycle of the system operation, the air quality sensors in each independent ventilation control zone, such as particulate matter sensors and volatile organic compound sensors, output raw concentration data according to a fixed sampling rate. The zone controller first buffers the raw concentration data of a number of consecutive preset sampling points.

[0050] The preset number of sampling points is represented by a sliding sampling window, which covers multiple consecutive system sampling periods;

[0051] The area controller is configured to enable the sliding sampling window during a constant background period when the pollution source equipment in the corresponding area is inactive and has undergone a preset emptying time.

[0052] During this background period, the standard deviation of the raw concentration data fluctuation mainly characterizes the inherent background electrical noise of the sensor, while the mean characterizes the baseline response. The area controller calculates the mean and standard deviation of the raw concentration data within this sliding sampling window, and uses the ratio of the mean to the standard deviation as the real-time signal strength, which serves as an objective measure of the sensor's inherent signal-to-noise ratio.

[0053] To avoid ratio distortion when the standard deviation is close to zero, the area controller presets a minimum noise lower limit; when the calculated standard deviation is less than this minimum noise lower limit, the minimum noise lower limit is used instead of the standard deviation in the real-time signal strength calculation.

[0054] The built-in calculation and processing sequence of the area controller is as follows: take the sample set formed by adjacent sampling points, calculate the mean and standard deviation of the sample set, and use the value of the mean divided by the standard deviation as the calculation parameter of the real-time signal strength;

[0055] The minimum noise limit is determined based on the calibration of the maximum tolerance range of the baseline output noise of the air quality sensor in an ideal clean environment;

[0056] As the sensor ages, the signal gain decreases and the noise floor increases, resulting in a reduction in the real-time signal strength. During the initial calibration, a standard signal strength is pre-stored. The area controller uses the ratio of the currently calculated real-time signal strength to the preset standard signal strength to determine the sensor sensitivity attenuation value.

[0057] The closer this ratio is to the preset upper limit, the closer the sensor output is to the initial state; the lower this ratio, the more obvious the sensor aging. To ensure consistency in subsequent judgments, the standard signal strength, aging threshold, and minimum noise lower limit are pre-calibrated and stored under the same sensor type and the same sampling rate.

[0058] Specifically, the preset emptying time is determined according to the time required for the corresponding area to maintain basic ventilation continuously after the pollution source equipment stops. The calibration method is as follows: during the installation and commissioning phase, the pollution source equipment in the corresponding area is shut down, and the area is kept continuously ventilated at the preset minimum operating air volume. The time it takes for the air quality sensor output to fall back to the stable background range is recorded.

[0059] After repeating at least three rounds of shutdown and fallback tests, the maximum value is taken as the preset clearing time for the area; the stable background range is determined by the difference between the maximum and minimum values ​​of the original concentration data in multiple adjacent sampling periods not exceeding the allowable background fluctuation value. The allowable background fluctuation value and the minimum noise lower limit are jointly calibrated under the same sensor type.

[0060] The preset aging threshold is determined as follows: new sensors, slightly aged sensors, and sensors nearing failure are selected from the same type of sensors for comparative testing. The sensor sensitivity attenuation value corresponding to the minimum resolution required for control is used as the aging threshold. The minimum noise lower limit is taken from the lower quartile of the standard deviation of the same type of sensor obtained from multiple rounds of sampling in a clean environment, so as to avoid the abnormal amplification of real-time signal strength due to accidental low noise.

[0061] When the sensor sensitivity attenuation value calculated by the area controller is less than the preset aging threshold, it indicates that the sensor has entered the severe degradation range. The area controller generates a maintenance alarm data packet and sends it to the edge controller and the upper monitoring terminal through the communication bus.

[0062] The maintenance alarm data packet includes at least the corresponding area identifier, sensor type, current sensitivity attenuation value, and alarm generation cycle, which is used by maintenance personnel to arrange replacement or verification; in this case, the sensor output is no longer used as a high-reliability feedback quantity to directly participate in fine adjustment.

[0063] When the sensor sensitivity attenuation value is greater than or equal to the preset aging threshold but less than the normal upper limit, the area controller performs compensation processing on the original concentration data; the compensation method adopts multiplicative compensation, that is, the original concentration data is divided by the sensor sensitivity attenuation value to obtain the corrected concentration;

[0064] To ensure that the compensation path has a clear input-output relationship, the area controller first determines whether the current sampling round is in a valid buffer state when performing compensation. If the aforementioned valid buffer condition is not met, the correction concentration is not output temporarily, and the valid correction concentration of the previous round is used. A buffer delay mark is added to the result of this round until the valid buffer condition is met in the next round, and then the update is resumed.

[0065] By correcting the reduction in output amplitude caused by sensor aging, subsequent airflow distribution and local adjustment are all performed based on the corrected concentration.

[0066] To avoid a sudden increase in compensation results when the sensor sensitivity decay value approaches the aging threshold, the area controller also sets a preset upper limit constraint on the correction concentration when performing compensation processing; when the compensated value exceeds the preset upper limit constraint, it outputs according to the preset upper limit constraint and simultaneously retains the maintenance alarm status.

[0067] The normal upper limit is used to define the healthy range of the sensor, where no compensation is required or only a small amount of compensation is needed. During calibration, it is preferable to select the upper boundary value of the sensor sensitivity decay value that is close to the initial calibration state.

[0068] When the current sensor sensitivity decay value is greater than or equal to the normal upper limit, the area controller keeps the original concentration data as the corrected concentration output and only records that the sensor is in normal condition without triggering a maintenance alarm.

[0069] The preset upper limit constraint of the corrected concentration is determined according to the minimum value among the upper limit of the corresponding sensor range, the upper limit of the target pollutant safety control, and the input range of the area controller, so as to ensure that the compensated feedback quantity does not exceed the effective characterization range of the sensor or the processing range of the subsequent control module.

[0070] Meanwhile, the current detection module installed on the power supply circuit of the pollution source equipment continuously outputs the power supply circuit current data as the equipment operating current; the current detection module can be composed of a current transformer and a data acquisition unit, and its output first enters the area controller; the area controller periodically samples the power supply circuit current data and judges the current change characteristics within a preset time window;

[0071] The triggering condition for the device start signal is: the power supply circuit current is greater than or equal to the preset start current threshold within the preset time window, and the current peak value is within the preset peak range.

[0072] Based on the starting current threshold and the preset peak range, the normal starting inrush current and short-term current fluctuation signals are distinguished by feature;

[0073] The area controller continuously reads multiple current sample values ​​at fixed sampling intervals within a preset time window, and is configured to verify that the current peak value falls within a preset peak range when multiple consecutive sample values ​​meet the start-up current threshold condition.

[0074] The starting current threshold and peak range are determined before the equipment is put into operation based on the test results of the no-load current, steady-state operating current and normal starting inrush current of the corresponding pollution source equipment: the starting current threshold is taken as the middle value that is higher than the upper limit of the no-load current fluctuation and not higher than the lower limit of the steady-state operating current, and the preset peak range covers the statistical distribution range of normal starting inrush current and avoids the short-term noise peak range.

[0075] The preset time window is calibrated according to the duration of the inrush current from its appearance to its decay and entry into a steady state. The fixed sampling interval is set according to the refresh cycle of the current detection module to cover at least five consecutive sampling points, so as to ensure that the judgment of multiple consecutive sampling values ​​is repeatable.

[0076] When the above two current determination conditions are met simultaneously, the area controller determines that the equipment start signal corresponding to the pollution source equipment is in an active state, and retrieves the preset rated air volume parameters of the pollution source equipment that are stored in advance.

[0077] The rated air volume parameter corresponds to the theoretical exhaust capacity required by the pollution source equipment under normal exhaust conditions; the area controller then multiplies the rated air volume parameter by the preset feedforward gain to calculate the initial air volume of the independent ventilation control area, and immediately writes it into the control output buffer of this area, while uploading the activation status to the edge controller; the preset feedforward gain is pre-configured by the control system based on the historical operation data of the equipment and stored in the local register.

[0078] Before pollutants are transmitted to the air quality sensor, the initial air volume is superimposed on the device start signal based on the activated state to compensate for the physical transport lag time of concentration feedback.

[0079] The preset feedforward gain is determined according to the capture efficiency requirements of the corresponding pollution source equipment under standard production load: first, the rated air volume parameter is used as the benchmark air volume for trial operation, and then the feedforward gain is gradually increased or decreased according to the preset step size set based on the percentage of the rated air volume parameter. The peak value of the corrected concentration during the preset observation period after the pollution source is started is compared to the target concentration requirement.

[0080] The gain point that meets the target concentration requirement and minimizes the increase in total air volume per unit time is taken as the preset feedforward gain for the pollution source equipment.

[0081] When the preset rated air volume parameter of a certain pollution source device is found to be empty, the area controller calls the default rated air volume parameter of the same type of device and generates a parameter missing prompt mark.

[0082] When the power supply circuit current data does not meet the starting current threshold condition, or although it reaches the threshold but the peak value is not within the preset peak range, the area controller determines that the equipment start signal is inactive and sets the initial air volume to zero; at this time, the subsequent air volume control in this area is mainly based on air quality feedback and does not add up the start feedforward amount.

[0083] After receiving the corrected concentration, sensor sensitivity attenuation value and equipment start signal uploaded by each independent ventilation control zone, the edge controller calculates the target air volume for each zone according to the preset target concentration requirements and preset total air volume limit requirements.

[0084] The preset target concentration requirement is the upper limit threshold of the preset concentration that the air quality in each independent ventilation control area can reach; the preset total air volume limit requirement is the upper limit of the total air volume that the multi-zone ventilation system can call.

[0085] The edge controller reads the pre-established mapping relationship between power consumption and air volume of the fan driven by the fan frequency converter, and then uses the difference between the corrected concentration of each area and its target concentration requirement as the basis for air volume demand.

[0086] For regions where the corrected concentration is greater than the preset target concentration requirement and the device start signal is active, their allocation priority is increased.

[0087] For areas where the corrected concentration is less than or equal to the preset target concentration requirement and the equipment start signal is inactive, reduce their allocation priority; complete the air volume allocation of each area within the total air volume limit requirement, output the target air volume of each independent ventilation control area and set the lower limit corresponding to the target air volume.

[0088] When an activated device starts up in a certain area, the edge controller will also raise the lower limit constraint of the target air volume in that area to no less than the initial air volume.

[0089] When the air volume requirement corresponding to the corrected concentration in the corresponding area is less than the initial air volume, the lower limit of the target air volume will be constrained to be no less than the initial air volume.

[0090] After receiving the target air volume from the edge controller, each area controller enters the local control execution phase. The area controller first reads the pre-acquired real-time wind speed data and the preset duct length data, and calculates the gas diffusion lag time based on the ratio of the two.

[0091] Real-time wind speed data is the fluid flow velocity in the duct collected by the duct wind speed sensor; preset duct length data is the effective physical fluid path length from the pollution source equipment to the air quality sensor sampling location.

[0092] The area controller uses the relationship between path length and real-time wind speed to obtain the transmission delay experienced by pollutants from the release point to the sensor sampling point, and compensates for the correction concentration in advance accordingly.

[0093] The advance compensation is based on the gas diffusion lag time to convert the current correction concentration to a time base and generate an equivalent concentration value for the feedback input of closed-loop control.

[0094] When the real-time wind speed data is lower than the preset minimum effective wind speed, in order to avoid abnormal amplification of the gas diffusion lag time, the area controller uses the preset minimum effective wind speed in the calculation and marks the current area as a low wind speed delay compensation state.

[0095] The preset minimum effective wind speed is determined as follows: During the installation and commissioning phase, the sensor response delay and wind speed measurement stability are recorded at different wind speeds. When the wind speed continues to decrease, causing the delay estimation fluctuation of multiple adjacent control cycles to exceed the preset allowable fluctuation range, the corresponding wind speed is determined as the preset minimum effective wind speed. The allowable fluctuation range is determined based on the degree of dispersion of the delay time measured in multiple rounds under stable operating conditions in the same duct.

[0096] After obtaining the pre-compensated corrected concentration, the area controller compares the concentration with the preset target concentration requirement to obtain the concentration deviation, and maps it to the airflow deviation based on the preset concentration-to-airflow conversion gain coefficient.

[0097] The airflow deviation is input to the proportional-integral (PI) control unit, where the microprocessor calculates the control airflow correction value using a discrete position PI algorithm. The specific formula is as follows:

[0098]

[0099] in, For the first The output corrected air volume for each control cycle. This represents the current airflow deviation. For the summation operator, From 1 to The control cycle historical time accumulated index variable, For the first Wind volume deviation at a historical moment This is the proportional adjustment coefficient. This is the integral adjustment coefficient;

[0100] The proportional part of the first term quickly corrects the fan control quantity based on the current deviation, while the integral part of the second term accumulates the deviation over multiple control cycles to eliminate persistent errors.

[0101] The area controller then combines the control output obtained from proportional-integral regulation with the target air volume and outputs a fan frequency conversion command. This fan frequency conversion command is converted into a corresponding output frequency signal by the frequency converter, which increases or decreases the fan speed, thereby causing the area air volume to gradually converge to the target air volume allocated by the edge controller.

[0102] During the execution of the fan frequency conversion command, the system does not directly assume that the execution result is valid, but continues to perform anomaly detection. The first type of anomaly detection is performed by the area controller reading the real-time wind speed data returned by the duct wind speed sensor, converting the theoretical wind speed value according to the target air volume corresponding to the fan frequency conversion command, calculating the absolute value of the difference between the real-time wind speed data and the theoretical wind speed value, and then calculating the ratio of the absolute value to the theoretical wind speed value to obtain the wind speed deviation rate.

[0103] If the wind speed deviation rate is greater than the preset maximum allowable deviation, it indicates that there may be mechanical transmission failure, abnormal increase in airflow resistance, or mismatch in the response of the actuator in the fan, valve, or pipeline. The area controller determines that the equipment is malfunctioning and generates a first status flag as a status flag. If the wind speed deviation rate is less than or equal to the maximum allowable deviation, it determines that the operation is normal and generates a second status flag as a status flag.

[0104] The second type of anomaly detection directly utilizes the aforementioned sensor sensitivity attenuation value. For example, when multiple sensors are configured in the same area, when an abnormal sensor is determined to be faulty, the area controller updates the status flag to shield the faulty sensor.

[0105] The third type of anomaly detection is achieved by a comparator circuit connected in parallel to the signal output terminal of the air quality sensor. When the voltage signal is greater than the preset voltage safety threshold, it is determined that a voltage over-limit anomaly has occurred, indicating that a rapidly rising dangerous concentration may occur in the air at the scene. The comparator circuit directly outputs a trigger signal to the hardware relay and simultaneously generates an emergency alarm message as a status marker.

[0106] When any status flag is determined to be in an abnormal state, the system immediately executes a safety protection action; for abnormal wind speed deviation, the area controller will switch the corresponding independent ventilation control area to the preset maximum air volume operation mode and feed the switching result back to the edge controller so that the target air volume of the independent ventilation control area can be adjusted in the next round to reduce the reliability of the area model;

[0107] In the event of severe aging and failure of a sensor, the system will stop using that sensor as the primary control basis and retain the maintenance alarm; or switch to a forced ventilation mode based on the device start signal.

[0108] In case of voltage over-limit abnormality, the hardware relay directly drives all fans in the relevant multi-zone ventilation system to switch to the preset maximum air volume operation mode to prioritize the rapid discharge of pollutants.

[0109] Through the above processing, the sampling, calibration, feedforward judgment, target allocation, local adjustment and anomaly protection in the system form a continuous data flow and control flow, so that air quality control utilizes both sensor feedback and pollution source equipment start signals, and still maintains controllable operation when actuators or sensors malfunction.

[0110] In a preferred embodiment of the present invention, the calculation of the target air volume for each independent ventilation control area according to the corrected concentration, the preset target concentration requirement and the preset total air volume limit requirement includes: establishing a mapping relationship between the power consumption and air volume of the fan driven by the fan frequency converter, allocating air volume based on the mapping relationship, the target concentration requirement and the total air volume limit requirement, outputting the target air volume for each independent ventilation control area and setting the lower limit corresponding to the target air volume.

[0111] When a device start signal is detected, the target air volume lower limit for the independent ventilation control zone is adjusted to the initial air volume;

[0112] The advance compensation includes: extracting historical correction concentrations and calculating the concentration change rate, combining the gas diffusion lag time with the concentration change rate to calculate the equivalent concentration value, and using the equivalent concentration value as the correction concentration after advance compensation.

[0113] The edge controller pre-stores the power consumption and air volume mapping relationship for each fan driven by the fan inverter; this mapping relationship is obtained by fitting a cubic polynomial function using the least squares method based on measurement data of the fan under multiple typical operating conditions. The specific formula is as follows:

[0114]

[0115] in, For the corresponding power consumption, For the allocated air volume, To match the fitting coefficients of the corresponding power dimension, they are pre-calibrated and stored in non-volatile memory during the factory testing phase;

[0116] The edge controller's internal storage area is pre-programmed with multiple sets of nonlinear mapping relationships between power consumption and air volume parameters of the fans driven by the fan frequency converter.

[0117] To this end, the edge controller reads the corrected concentration, target concentration requirements, total air volume limit requirements, and equipment start signals for each region in each optimization cycle, and substitutes these data into the air volume allocation model.

[0118] The preset target concentration requirement is determined based on the occupational health limits of the corresponding area, the process allowable residual concentration, and the background ventilation capacity. The upper limit of the concentration corresponding to the most stringent one is selected as the control target. The preset total air volume limit requirement is determined based on the minimum permissible value among the current power supply capacity, the rated capacity of the fan, and the upper limit of the allowable pressure drop of the main pipeline. The edge controller is allowed to update the limit in a time-sharing manner according to the shift load or power supply control logic.

[0119] The edge controller first calculates the exhaust volume requirement for each area based on the difference between the current corrected concentration and the target concentration requirement. The specific algebraic conversion formula is as follows:

[0120]

[0121] in, For ventilation demand, The preset minimum operating air volume for the corresponding area. For the current corrected concentration, To meet the target concentration requirements, This is the preset concentration-to-airflow conversion gain coefficient. This is a function that takes the maximum value among the terms within the parentheses.

[0122] If the difference between the corrected concentration in a certain area and the preset target concentration requirement is greater than the preset first concentration difference threshold, then the air volume demand parameter for that area in the current allocation cycle is set to the first preset air volume level; if the difference is less than or equal to the preset second concentration difference threshold, then the air volume demand parameter is set to the second preset air volume level; wherein, the preset first concentration difference threshold and the preset second concentration difference threshold are pre-calibrated and stored based on the statistical analysis of pollutant diffusion rate and environmental tolerance in the historical on-site operation data;

[0123] The edge controller calls the power consumption and air volume mapping relationship of the corresponding fan and allocates air volume to all independent ventilation control areas without exceeding the total air volume limit.

[0124] The edge controller executes an optimization algorithm based on the mapping relationship, outputs the target air volume for each independent ventilation control zone, and sets the lower limit corresponding to the target air volume. The constraints include: the corrected concentration in each zone is less than the preset target concentration requirement, and the total fan operating power consumption parameter is lower than the preset power consumption upper limit.

[0125] To make the air volume allocation rules clearer, the edge controller first generates candidate target air volumes based on the exhaust air demand of each area within the same allocation cycle, and then checks whether the sum of all candidate target air volumes exceeds the total air volume limit; if it does not exceed the limit, the candidate target air volume is kept as the output result.

[0126] When the demand exceeds the limit, the reduction is performed according to the allocation weight corresponding to the exhaust demand of each area; to avoid the risk of millisecond-level time-series allocation timeout caused by multiple rounds of loop verification, the edge controller adopts a deterministic one-dimensional proportional reduction rule during reduction:

[0127] The remaining allocable air volume is obtained by subtracting the sum of the preset minimum operating air volume of all areas from the total air volume limit requirement. The dynamic excess demand is obtained by subtracting the preset minimum operating air volume from the candidate target air volume of each area. The remaining allocable air volume is multiplied by the ratio of the dynamic excess demand of a single area to the sum of the dynamic excess demand of all over-limit areas, and then added to the preset minimum operating air volume of that area. The reduced target air volume is calculated in one go to ensure that the control algorithm completes the allocation within a single machine cycle.

[0128] For areas where the corrected concentration is lower than the target concentration requirement and there is no equipment start signal, the edge controller allows its target air volume to be kept above the preset minimum operating air volume in order to maintain basic ventilation.

[0129] The weighting is not an arbitrary combination of different physical quantities, but rather a ranking and determination of the priority of exhaust demand under the same dimension. Specifically, it is given in the following order: compare the degree of exceedance of the target concentration requirement by the corrected concentration in each area, and the higher the degree of exceedance, the higher the priority.

[0130] When the concentration values ​​exceeding the standard are within the same preset priority range, if the equipment start signal is in an active state, the first priority is assigned weight; if the active states are the same, the air volume gap values ​​of each area in the previous control cycle are compared, and the one with the larger air volume gap value is assigned weight as the second priority.

[0131] After assigning weights to each region in the above order, the edge controller first satisfies the candidate target air volume of the high priority region, and then allocates the remaining air volume in order of priority from high to low until the total air volume limit requirement is met.

[0132] The preset minimum operating air volume is determined according to the lower limit of the air exchange rate of the corresponding area or the basic ventilation specifications on site, and the larger value that can maintain the background air renewal during non-production periods is selected to prevent individual areas from being below the basic ventilation level for a long time when the total volume is compressed.

[0133] When an activated device starts up in a certain area, the edge controller will not simply make a static allocation based on the corrected concentration uploaded by the current sensor, but will further check the initial air volume corresponding to that area; if the target air volume calculated based on the concentration feedback is lower than the initial air volume, the lower limit of the target air volume of the independent ventilation control area will be adjusted to the initial air volume.

[0134] If the target air volume calculated based on concentration feedback is already higher than the initial air volume, then the higher value will be maintained as the target air volume for that area.

[0135] By raising the target airflow lower limit to the initial airflow, the physical transport delay from equipment startup to the arrival of pollutants at the sensor sampling point is compensated;

[0136] If multiple regions simultaneously have activated device start signals, the edge controller first applies a lower limit constraint of no less than the initial air volume to each region, and then performs a total balance allocation of the remaining allocable air volume.

[0137] If the sum of the initial air volume of multiple activated areas is greater than or equal to the total air volume limit requirement, the edge controller retrieves the preset safety risk level sorting list, sets the lower limit of the air volume of the top-ranked area as the initial air volume of that area, and the remaining areas maintain at least the preset minimum operating air volume. At the same time, a total limited alarm flag is generated to indicate that the current system is in a limited protection allocation state, thereby avoiding the situation where the total allocation result alone masks the obvious insufficient exhaust in local areas under extreme working conditions.

[0138] After the edge controller completes the target air volume allocation, it sends the target air volume of each area to the corresponding area controller. After receiving the target air volume, the area controller does not directly convert it into the inverter output, but first performs advance compensation processing. The real-time wind speed data used for advance compensation is provided by the duct wind speed sensor, and the preset duct length data is stored in the parameter area of ​​the area controller.

[0139] The pipeline length data corresponds to the effective transport path length of pollutants from the location of the pollution source equipment to the sampling location of the air quality sensor; the area controller reads real-time wind speed data and pipeline length data within the current control cycle, and updates the gas diffusion lag time based on the relationship between the two.

[0140] The gas diffusion lag time is negatively correlated with real-time wind speed data; the preset pipeline length data is written into the parameter area in combination with the on-site pipeline layout diagram and measurement results during the system debugging phase; when there are multiple bends, branch convergences, or sensor sampling branches in the pipeline, the effective transport path length is determined by the cumulative mainstream flow path of pollutants from the pollution source equipment to the sampling point, rather than simply taking the straight-line distance in the plane;

[0141] The area controller updates the gas diffusion lag time based on the ratio of preset pipe length data to real-time wind speed data, and rounds the lag time up to the corresponding number of control cycles. When the real-time wind speed data is lower than the preset minimum effective wind speed, the preset minimum effective wind speed is used in the ratio calculation to avoid excessive amplification of the lag time.

[0142] After obtaining the updated gas diffusion lag time, the area controller extracts the historical control quantity and historical compensation concentration data for the corresponding time period from the local cache, and makes advance compensation adjustments to the current correction concentration in the time dimension.

[0143] In specific processing, the regional controller extracts the historical corrected concentration in the local cache based on the first-order trend prediction principle to calculate the rate of change of the current corrected concentration, and combines the current corrected concentration with the rate of change and the gas diffusion lag time. In this way, it uses the difference between the prediction value without delay and the prediction value with delay to construct an equivalent feedback quantity that is closer to the pollution state of the pollution source.

[0144] During the specific calculation process, the area controller obtains the current sampling time. The corresponding current correction concentration and the corrected concentration at the previous adjacent complete sampling time. And combined with a fixed control sampling period The rate of change was calculated. :

[0145]

[0146] Utilizing gas diffusion lag time Generate the equivalent feedback concentration for advance compensation:

[0147]

[0148] When calculated When the concentration is lower than the preset system environment background value, the area controller will assign the equivalent concentration to the system environment background value to prevent negative overcompensation.

[0149] The area controller uses the gas diffusion lag time to perform time phase compensation on the correction concentration, which includes the delay, and outputs the equivalent concentration aligned to the current control moment.

[0150] Before calculating the rate of change, the regional controller performs amplitude limiting filtering on the historical corrected concentration. The logic of amplitude limiting filtering is as follows: assuming the current sampled value is... The filter output value at the previous moment was The preset change limit is ;

[0151] when At that time, the current filter output value is ;

[0152] when At that time, the current filter output value is ;

[0153] when At that time, the current filter output value is ;

[0154] Therefore, it does not change the overall direction of change over multiple consecutive control cycles;

[0155] The preset upper limit of change is determined by calibration based on the maximum concentration change allowed within a unit control cycle under normal production switching conditions. During calibration, the upper limit of the normal change peak value in multiple rounds of measured data is used as the basis, and confirmed high-frequency noise jump points of the sensor are removed.

[0156] The length of historical data used for advance compensation should at least cover the number of sampling points corresponding to one gas diffusion lag time. When the local cache length is insufficient to cover the number of sampling points, the area controller uses the most recent complete cache result before the current control cycle as a substitute and simultaneously marks it as a cache degradation compensation state to ensure that the selection conditions between different compensation paths are clear and executable.

[0157] After the pre-compensation adjustment, the area controller compares the target air volume allocated by the edge controller with the correction concentration fed back by the duct wind speed sensor to obtain the air volume deviation used for proportional-integral regulation.

[0158] Proportional-integral control is used to eliminate the static deviation between the regional execution air volume and the target air volume, and to perform dynamic tracking compensation in response to changes in the correction concentration; a multi-region cascaded control architecture is used to synchronously perform global total air volume allocation and single-region local delay compensation.

[0159] After adopting the above method, in the stage when the pollution source is just started and the sensor has not yet fully responded, the target air volume lower limit is limited by the initial air volume as the minimum constraint, so as to avoid the exhaust volume of the area exhaust not meeting the standard in the initial stage.

[0160] During the transmission of pollutants, the gas diffusion lag time, determined by the real-time wind speed and the duct length, makes the application time of the corrected concentration closer to the site, thereby reducing the adjustment lag caused by measurement delay. As a result, the multi-zone ventilation system can still meet air quality requirements and fan operation control under the condition of limited total air volume.

[0161] In a preferred embodiment of the present invention, the anomaly detection includes: within a preset time length after the output of the fan frequency conversion command, acquiring real-time wind speed data through a duct wind speed sensor, and calculating the theoretical wind speed value based on the target air volume corresponding to the fan frequency conversion command and the preset duct cross-sectional area parameters.

[0162] Calculate the wind speed deviation rate based on real-time wind speed data and theoretical wind speed values;

[0163] When the wind speed deviation rate is greater than the preset maximum allowable deviation, a first state flag indicating equipment malfunction is generated, the independent ventilation control area is switched to the preset maximum airflow operation mode, and the target airflow for the independent ventilation control area is adjusted; when the wind speed deviation rate is less than or equal to the preset maximum allowable deviation, a second state flag indicating normal operation is generated.

[0164] Each independent ventilation control area is equipped with two air quality sensors. Anomaly detection also includes: obtaining the sensor sensitivity attenuation value of the two air quality sensors in the same independent ventilation control area, and determining the consistency deviation based on the absolute value of the difference between the sensor sensitivity attenuation values ​​of the two air quality sensors.

[0165] When the consistency deviation is greater than the preset consistency threshold, the sensor sensitivity attenuation values ​​of the two air quality sensors are compared. The air quality sensor with the smaller sensor sensitivity attenuation value is identified as the failure node, and the status flag is updated. The sampling data of the failure node is removed in the subsequent closed-loop control adjustment.

[0166] When the consistency deviation is less than or equal to the preset consistency threshold, the air quality sensor is determined to be in normal consistency, and the current control mode is maintained.

[0167] When the sensor sensitivity decay values ​​of both air quality sensors are less than the preset aging threshold, the system switches to forced ventilation mode based on the device start signal and limits the target air volume of the independent ventilation control area to the preset upper limit value.

[0168] Anomaly detection also includes: obtaining a voltage signal by a comparator circuit connected in parallel with the signal output of the air quality sensor;

[0169] When the voltage signal exceeds the preset voltage safety threshold, an overvoltage abnormality is determined. Within a predetermined response time, a hardware relay electrically connected to the comparator circuit triggers all fans driven by the fan frequency converter in the multi-zone ventilation system to switch to the preset maximum air volume operation mode, and generates an emergency alarm message as a status marker.

[0170] When the voltage signal is less than or equal to the preset voltage safety threshold, maintain the current normal status flag.

[0171] After the area controller outputs the fan frequency conversion command to the frequency converter, the fan enters the corresponding speed operation state; in order to determine whether the actuator works according to the command, the area controller reads the real-time wind speed data returned by the duct wind speed sensor within a preset time length; the preset time length is the preset time interval from the output of the fan frequency conversion command to the fan speed and the airflow in the duct reaching a stable response state;

[0172] At the same time, the area controller calculates the theoretical wind speed value based on the target air volume corresponding to the frequency conversion command of the fan and the preset duct cross-sectional area parameters. Then, the area controller calculates the absolute value of the difference between the real-time wind speed data and the theoretical wind speed value, and further divides it by the theoretical wind speed value to obtain the wind speed deviation rate.

[0173] To avoid amplifying the deviation rate when the theoretical wind speed value is too low, the area controller compares the converted theoretical wind speed value with the preset minimum theoretical wind speed; when the theoretical wind speed value is less than the preset minimum theoretical wind speed, the preset minimum theoretical wind speed is used as the benchmark for calculating the deviation rate.

[0174] The preset time length is determined according to the response time required for the wind turbine to enter the stable range from receiving the frequency conversion command. Specifically, it can be obtained through multiple step speed increase and decrease tests during the commissioning phase, and the time that covers the stable response under most operating conditions is taken as the judgment window.

[0175] The preset maximum allowable deviation is determined based on the upper limit of the wind speed tracking error statistics of the same type of fan, air valve and air duct under normal operating conditions. It is preferred to take the value after retaining a safety margin outside the upper limit of the normal error distribution.

[0176] The preset minimum theoretical wind speed is calculated based on the cross-sectional area of ​​the duct and the preset minimum operating air volume to ensure that the deviation rate calculation is still comparable under low air volume conditions.

[0177] When the wind speed deviation rate is greater than the preset maximum allowable deviation, it means that although the frequency converter has received the command, the execution result of the fan, air valve or air duct does not match the theoretical state.

[0178] This discrepancy may originate from engineering malfunctions such as abnormal mechanical transmission, partial blockage of air ducts, or valves not being in position. In this case, the area controller determines that the equipment is malfunctioning, generates a first status flag, and immediately switches the corresponding independent ventilation control area to the preset maximum airflow operation mode.

[0179] Here, the preset maximum air volume operation mode is configured as follows: the area controller does not use the conventional proportional-integral regulation result, but directly outputs the operation command corresponding to the preset upper limit to the frequency converter to prioritize the exhaust capacity of the area.

[0180] When the system determines that the wind speed deviation rate exceeds the limit and the exhaust volume fails to meet the standard, it provides the maximum negative pressure suction capacity under the current physical channel architecture by outputting the highest preset threshold command, and performs passive fault protection.

[0181] Meanwhile, to avoid damage to the fan back pressure or negative pressure deformation of the pipeline due to unrestricted output of the maximum operating command when facing extreme faults such as complete blockage of the air duct, the preset maximum air volume operating mode is subject to the hard constraint of the inherent overload current protection threshold of the inverter in the underlying electrical circuit. Once the motor operating current reaches the safety limit, it will automatically limit or stop, thus taking into account both maximum personnel protection and basic equipment safety in fault conditions.

[0182] At the same time, the area controller will synchronously send the fault status and current operating mode to the edge controller. The edge controller will then adjust the target air volume of the independent ventilation control area accordingly to avoid subsequent optimizations from allocating an inappropriate air volume to the area based on the normal execution capacity.

[0183] Adjusting the target airflow for this independent ventilation control zone specifically means that the edge controller reduces the confidence weight of this zone calculated based on the conventional model in subsequent allocation cycles, and marks this zone as a fault protection priority zone:

[0184] When the total air volume allows, it maintains its preset maximum air volume operation mode. When the total air volume is limited, it maintains at least the larger of its preset minimum operating air volume and the air volume required for current safety protection. The remaining adjustable air volume is redistributed to other normal areas, so that the adjustment and distribution instructions have a clear execution path.

[0185] When the wind speed deviation rate is less than or equal to the maximum allowable deviation, the area controller determines that the current operation is normal and generates a second status flag.

[0186] At this point, it indicates that the consistency between the fan frequency conversion command and the wind speed meets the requirements, and the area continues to operate according to the original control mode without triggering a forced switch.

[0187] Through this verification process, the system does not only check whether a command has been issued, but further verifies whether the command has actually turned into a change in wind speed, thereby corresponding the control result with the air delivery capacity.

[0188] When each independent ventilation control zone is equipped with at least two air quality sensors, the zone controller also performs a dual-sensor consistency check;

[0189] Specifically: First, calculate the sensor sensitivity attenuation value of each of the two air quality sensors in the same area as described above, and then calculate the absolute value of the difference between the two attenuation values; evaluate the consistency deviation based on the two; this consistency deviation reflects the degree of consistency of the health status of the two sensors;

[0190] If the consistency deviation is greater than the preset consistency threshold, it is determined that the output deviation of at least one of the two sensors is greater than the preset deviation threshold, and the sensor abnormality judgment logic is triggered.

[0191] The consistency threshold is determined by long-term comparative data of two sensors of the same model operating synchronously in the same area. The upper bound of the distribution of the difference in the sensitivity attenuation values ​​of the two sensors under normal conditions is taken and the value after adding the installation position difference margin is added to avoid misjudging reasonable individual differences as failures.

[0192] When the consistency deviation is greater than the preset consistency threshold, the area controller determines that the corresponding abnormal sensor has failed and updates the status flag to mask the failed sensor.

[0193] Shielding is used to remove the sampling node data of the corresponding failed sensor in the subsequent closed-loop control adjustment, and only use the sampling data of the non-failed sensor as the feedback input;

[0194] To determine which sensor is an abnormal node, the area controller can combine the sensitivity decay value and historical trend of each sensor and prioritize the side with the worse health status as the failed node.

[0195] When the consistency deviation between the two is less than or equal to the preset consistency threshold, and the difference between the absolute value of the rate of change of one and the absolute value of the rate of change of the other in multiple consecutive control cycles is greater than the preset fluctuation difference threshold, the side with the larger absolute value of the rate of change is identified as an abnormal node.

[0196] Through the above processing, even if one of the two sensors in the same area shows obvious drift, the system can still maintain basic control capability by relying on the other sensor; the continuous multiple control cycles mentioned here are preferably no less than three continuous control cycles, so as to avoid single-cycle occasional fluctuations directly triggering failure judgment;

[0197] A more pronounced deviation trend means that the same sensor, relative to another sensor in the same region or relative to its own historical stable range, continuously changes in a direction away from the normal attenuation zone, and the cumulative deviation continues to increase.

[0198] When the sensor sensitivity decay values ​​of two air quality sensors in the same area are both less than the preset aging threshold, it indicates that both feedback nodes in the area have entered the severe aging range. At this time, relying on their concentration feedback will significantly reduce the control reliability.

[0199] To avoid continuous interference from distorted feedback, the area controller switches to a forced exhaust mode based on the device start signal and limits the target air volume of the independent ventilation control area to a preset upper limit.

[0200] The forced exhaust mode triggers corresponding control actions based on the equipment start signal and stops the closed-loop continuous adjustment based on the air quality sensor sampling value; by applying a preset upper limit value to limit the output air volume in the forced exhaust mode, the peak value of the corresponding pollutant concentration is controlled when the sensor is determined to be aging and failing.

[0201] The preset upper limit value is determined by taking into account the allowable upper limit of long-term continuous operation of the fan in the corresponding area, the bearing capacity of the duct structure, and the occupational health risk level of the area, and the higher safe air volume value that can take into account both equipment safety and personnel protection is selected.

[0202] In addition to the software judgment mentioned above, the system also sets up a comparator circuit connected in parallel to the signal output terminal of the air quality sensor; the comparator circuit directly acquires the voltage signal output by the air quality sensor and compares it with a preset voltage safety threshold at the hardware level.

[0203] The voltage signal represents the quantitative change in the concentration of pollutants in the air in real time; the comparator circuit, based on hardware level threshold comparison logic, triggers a hardware power-off protection action for concentration step over-limit within the first preset response time threshold.

[0204] When the voltage signal exceeds the preset voltage safety threshold, the comparator circuit directly determines that a voltage over-limit abnormality has occurred, and within a predetermined response time, triggers all fans driven by the fan frequency converter in the multi-zone ventilation system to switch to the preset maximum air volume operation mode through a hardware relay electrically connected to the comparator circuit.

[0205] The predetermined response time is determined by the sum of the maximum electromechanical action delay time required from the time the hardware relay receives the trigger signal to the time the wind turbine inverter completes the switching to the highest operating capacity and the longest staggered acceleration ramp time.

[0206] The trigger signal output by the hardware relay is connected in parallel to the highest priority digital forced input terminal of each wind turbine frequency converter;

[0207] Furthermore, each inverter is pre-set with an alternating and increasing safe acceleration ramp time, thereby converting the hardware electrical signals issued at the same time into staggered electromechanical ramp loads on the grid time axis at the physical execution level, and steadily reaching the preset maximum air volume operation mode while avoiding electrical and physical timing conflicts.

[0208] Meanwhile, the comparator circuit or its connected interface unit generates and reports emergency alarm information to the edge controller and monitoring terminal and saves it as a status flag;

[0209] Since this action does not depend on whether the area controller is executing the program normally, the protection action is directly triggered by the physical path formed by the comparator circuit and the hardware relay electrically connected to it, even when the microprocessor software module has not issued a frequency conversion adjustment command.

[0210] To prevent malfunctions caused by transient interference pulses at the sensor input, the voltage over-limit judgment of the comparator circuit also requires the voltage signal to continuously exceed the preset voltage safety threshold for a preset confirmation time before driving the hardware relay to perform switching.

[0211] The preset voltage safety threshold is determined based on the calibration relationship between the output voltage of the air quality sensor and the concentration of the target pollutant, and a voltage value with a safety margin below the corresponding dangerous alarm concentration is selected.

[0212] The preset confirmation time is determined based on the anti-interference test results of the comparator circuit input terminal, and it is required to be longer than the duration of the transient pulse but shorter than the allowable response time when the dangerous concentration accumulates rapidly to the point where emergency ventilation is required.

[0213] When the voltage signal is less than or equal to the preset voltage safety threshold, the comparator circuit does not trigger the relay action, the system maintains the current normal state mark, and continues to operate according to the fan frequency conversion command given by the edge controller and the area controller in coordination.

[0214] Therefore, the wind speed deviation rate is used to verify whether the actuator is in place, the dual sensor consistency is used to identify whether the feedback node is reliable, and the comparator circuit is used to handle the software bypass protection under high-risk concentration. The three correspond to execution abnormality, feedback abnormality and extreme concentration abnormality, respectively. When used together, the multi-zone ventilation system can maintain an operational state under both normal and abnormal operating conditions.

[0215] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A closed-loop control method for ventilation equipment in response to air quality data, used in a multi-zone ventilation system, the multi-zone ventilation system comprising multiple independent ventilation control zones, each of the independent ventilation control zones being equipped with a pollution source device, an air quality sensor, a duct wind speed sensor, and a current detection module connected to the power supply circuit of the pollution source device, and each of the independent ventilation control zones being equipped with a fan and a fan frequency converter electrically connected to the fan, characterized in that, include: The raw concentration data collected by the air quality sensors in the multiple independent ventilation control areas are acquired, and the raw concentration data is calibrated to obtain the corrected concentration. Acquire the power supply circuit current data collected by the current detection module in each of the independent ventilation control areas; when the equipment start signal of the pollution source equipment is detected based on the power supply circuit current data, generate the initial air volume of the corresponding independent ventilation control area. Based on the corrected concentration, the preset target concentration requirement, and the preset total air volume limit requirement, determine the target air volume for each of the independent ventilation control zones; The system acquires real-time wind speed data for each independent ventilation control zone, determines the gas diffusion lag time based on the real-time wind speed data and preset duct length data, uses the gas diffusion lag time to pre-compensate the correction concentration, and outputs a fan frequency conversion command based on the pre-compensated correction concentration and the target air volume. During the execution of the wind turbine frequency conversion command, anomaly detection is performed, a corresponding status flag is generated, and a safety protection action is triggered when an abnormal status is determined.

2. The closed-loop control method for ventilation equipment responding to air quality data according to claim 1, characterized in that, The original concentration data is calibrated to obtain the corrected concentration, including: Obtain raw concentration data for a preset number of sampling points, extract the real-time signal intensity corresponding to the raw concentration data, and determine the sensor sensitivity attenuation value based on the real-time signal intensity and the preset standard signal intensity. When the sensor sensitivity decay value is less than the preset aging threshold, a maintenance alarm data packet is generated; When the sensor sensitivity decay value is greater than or equal to the preset aging threshold, the original concentration data is compensated to obtain the corrected concentration.

3. The closed-loop control method for ventilation equipment responding to air quality data according to claim 1, characterized in that, The initial air volume for generating the corresponding independent ventilation control zone includes: The current data of the power supply circuit is monitored in real time by a current detection module installed on the power supply circuit of the pollution source equipment as the equipment operating current. When the equipment operating current is detected to be greater than or equal to a preset starting current threshold within a preset time window and the current peak value is within a preset peak range, the equipment start signal is determined to be in an active state, and the initial air volume is determined according to the preset rated air volume parameter of the pollution source equipment; otherwise, the equipment start signal is determined to be in an inactive state, and the initial air volume is set to zero.

4. The closed-loop control method for ventilation equipment responding to air quality data according to claim 1, characterized in that, Based on the corrected concentration, the preset target concentration requirement, and the preset total airflow limit requirement, the target airflow for each of the independent ventilation control zones is determined as follows: Establish a mapping relationship between the power consumption and air volume of the fan driven by the fan inverter, allocate air volume based on the mapping relationship, the target concentration requirement and the total air volume limit requirement, output the target air volume of each independent ventilation control area and set the lower limit corresponding to the target air volume; When the device start signal is detected, the target air volume lower limit of the independent ventilation control area is adjusted to the initial air volume.

5. The closed-loop control method for ventilation equipment responding to air quality data according to claim 1, characterized in that, The advance compensation includes: Extract historical corrected concentrations and calculate the concentration change rate. Combine the gas diffusion lag time with the concentration change rate to calculate the equivalent concentration value, and use the equivalent concentration value as the corrected concentration after advance compensation.

6. The closed-loop control method for ventilation equipment responding to air quality data according to claim 1, characterized in that, The anomaly detection includes: Within a preset time period after the fan frequency conversion command is output, the real-time wind speed data is acquired through the duct wind speed sensor, and the theoretical wind speed value is calculated based on the target air volume corresponding to the fan frequency conversion command and the preset duct cross-sectional area parameters; the wind speed deviation rate is calculated based on the real-time wind speed data and the theoretical wind speed value. When the wind speed deviation rate is greater than the preset maximum allowable deviation, a first state flag indicating a fault in the equipment is generated, and the independent ventilation control area is switched to the preset maximum airflow operation mode, and the target airflow for the independent ventilation control area is adjusted; when the wind speed deviation rate is less than or equal to the preset maximum allowable deviation, a second state flag indicating normal operation is generated.

7. The closed-loop control method for ventilation equipment responding to air quality data according to claim 2, characterized in that, Each of the aforementioned independent ventilation control zones is equipped with two of the aforementioned air quality sensors, and the anomaly detection also includes: Obtain the sensor sensitivity attenuation values ​​of two air quality sensors within the same independent ventilation control area, and determine the consistency deviation based on the absolute value of the difference between the sensor sensitivity attenuation values ​​of the two air quality sensors; When the consistency deviation is greater than the preset consistency threshold, the sensor sensitivity attenuation values ​​of the two air quality sensors are compared. The air quality sensor with the smaller sensor sensitivity attenuation value is identified as a failure node, and the status flag is updated. The sampling data of the failure node is removed in the subsequent closed-loop control adjustment. When the consistency deviation is less than or equal to the preset consistency threshold, the air quality sensor is determined to be in normal consistency, and the current control mode is maintained. When the sensor sensitivity attenuation values ​​of both air quality sensors are less than the preset aging threshold, the system switches to a forced exhaust mode based on the device start signal and limits the target airflow of the independent ventilation control area to a preset upper limit value.

8. The closed-loop control method for ventilation equipment responding to air quality data according to claim 1, characterized in that, The air quality sensor includes a signal output terminal, and the anomaly detection further includes: The voltage signal is obtained by a comparator circuit connected in parallel with the signal output terminal; When the voltage signal exceeds the preset voltage safety threshold, an overvoltage anomaly is determined. Within a predetermined response time, a hardware relay electrically connected to the comparator circuit triggers all fans in the multi-zone ventilation system driven by the fan inverter to switch to the preset maximum airflow operation mode, and an emergency alarm message is generated. When the voltage signal is less than or equal to the preset voltage safety threshold, the current normal operation status is maintained.

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