Air quality monitoring and intelligent control system

Abstract

The invention relates to the technical field of indoor air monitoring, and discloses an air quality monitoring and intelligent control system, which comprises a power supply bottom plate used for providing stable power supply required by the system; the main control panel is used as an interface for interaction between a user and the system; the two WIFI Bluetooth modules are connected with the main control panel and external equipment and are used for realizing communication connection between the system and the external equipment; the air quality monitoring module is connected with the main control panel and used for monitoring the indoor air quality and evaluating the indoor air quality; and the air conditioning system control module is connected with the main control panel and the power supply bottom plate, and is used for controlling the operation of the air conditioning system and realizing the adjustment of the indoor temperature. By additionally arranging the two WIFI Bluetooth modules, the relay and the RES485 communication module, three-in-one integrated control over floor heating, fresh air and air conditioning is achieved, the system can intelligently manage and control different devices, the overall efficiency and convenience are improved, one machine has multiple purposes, and functionality is high.

Description

Technical Field

[0001] The present invention relates to the technical field of indoor air monitoring, and particularly to an air quality monitoring and intelligent control system. Background Art

[0002] With the support of the Internet of Things technology, people have been able to achieve wireless communication between different devices. This convenient communication technology has made remarkable progress in the fields of transportation, energy, and construction in terms of remote monitoring and control. In the built environment field, commercial indoor air quality (IAQ) sensors have also made significant improvements in recent years. They can collect monitoring information through the Internet of Things technology and send it to the cloud server. In recent years, a large number of studies have used commercial indoor air quality sensors and the Internet of Things technology for daily monitoring of indoor air quality. With the gradual in-depth research of the Internet of Things technology in the field of indoor air quality control, in recent years, the number of published papers on the development or application of the Internet of Things platform to carry out indoor air quality research has shown an increasing trend. Air quality monitoring refers to the process of real-time monitoring and evaluation of various air pollutants and pollutant concentrations in the environment. And the air quality monitoring and intelligent control system is a system that combines sensing technology, data processing, intelligent algorithms, and control strategies, aiming to real-time monitor and evaluate the environmental air quality, and adjust and optimize the air quality through intelligent control means.

[0003] At present, traditional thermostats only have single or two-in-one control functions and cannot achieve the integrated control of floor heating, fresh air, and air conditioning. Each thermostat works independently, lacking overall coordination and integrated control capabilities. Moreover, traditional thermostats usually adopt conventional control panels and pure mechanical switch designs, lacking intelligent and network connection functions, and unable to achieve remote control and intelligent adjustment. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides an air quality monitoring and intelligent control system, which solves the problems that the traditional thermostat system only has single or two-in-one control functions, each thermostat works independently, lacking overall coordination and integrated control capabilities, and lacking intelligent and network connection functions, and unable to achieve remote control and intelligent adjustment.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions: An air quality monitoring and intelligent control system, comprising:

[0006] A power supply base plate, which is used to provide a stable power supply required by the system;

[0007] A main control panel, which is used as an interface for users to interact with the system;

[0008] Two Wi-Fi Bluetooth modules, which are connected to the main control panel and external devices, and are used to realize the communication connection between the system and external devices;

[0009] An air quality monitoring module, which is connected to the main control panel and is used to monitor and evaluate the indoor air quality;

[0010] An air-conditioning system control module, which is connected to the main control panel and the power supply base plate, and is used to control the operation of the air-conditioning system to realize the adjustment of the indoor temperature;

[0011] A floor heating control module, which is connected to the main control panel and is used to control the start and stop of the floor heating system to maintain the indoor temperature.

[0012] Preferably, the power supply base plate includes an EMC protection circuit, a rectification circuit with isolated switch power supply voltage bias, a transformer, a step-down circuit and a feedback circuit. The EMC protection circuit is used to protect the circuit from electromagnetic interference;

[0013] The rectification circuit with isolated switch power supply voltage bias is used to convert alternating current into direct current and keep it stable;

[0014] The transformer and the step-down circuit are used to provide different voltage outputs;

[0015] The feedback circuit is used to detect the change of the transformer output load and ensure the stability of the output voltage by adjusting the control signal.

[0016] Preferably, the EMC protection circuit is connected to the main circuit board of the power supply base plate, the rectification circuit with isolated switch power supply voltage bias is connected to the input end of the transformer, and the feedback circuit is connected to the input end of the transformer.

[0017] Preferably, the main control panel includes a touch key unit, an LCD screen and a backlight, and an RS485 communication circuit. The touch key unit is used for users to interact with the system;

[0018] The LCD screen and the backlight are used to be controlled by the MCU through the LCD driver chip to display the system status and information;

[0019] The RS485 communication circuit is used to connect to the air-conditioning line panel to realize the control of the central air-conditioning system.

[0020] Preferably, the touch key unit is connected to the control circuit board of the main control panel through a flexible cable, the LCD screen and the backlight are connected to the LCD driver chip of the main control panel through a flexible cable, and the RS485 communication circuit is connected to the communication interface of the main control panel.

[0021] Preferably, the air quality monitoring module includes a sensor unit, a fuzzy logic reasoning unit, an air quality index generation unit, and a fuzzy logic controller. The sensor unit is used to collect data related to indoor air quality;

[0022] The fuzzy logic reasoning unit is used to analyze the collected indoor air quality by using the fuzzy logic reasoning method;

[0023] The air quality index generation unit is used to calculate and generate an indoor air quality index according to the result of fuzzy logic reasoning;

[0024] The fuzzy logic controller is used to identify the clustering index of the air quality index and perform control according to the evaluation result of the air quality parameters.

[0025] Preferably, the air conditioning system control module includes a temperature error calculation unit, a control strategy judgment unit, a PID parameter tuning unit, a feedforward control unit, and a lag compensation control unit. The temperature error calculation unit is used to calculate the error between the actual indoor temperature and the set temperature;

[0026] The control strategy judgment unit is used to judge which control strategy to adopt according to the magnitude of the temperature error and the stage of the system;

[0027] The PID parameter tuning unit is used to tune the parameters of the PID controller by using the critical ratio method;

[0028] The feedforward control unit is used to output a signal to control the opening degree of the air conditioning coil electric valve according to the change range of temperature and flow rate;

[0029] The lag compensation control unit is used to design a lag compensation control rule according to the time-delay characteristics of the system, so that the control variable is adjusted according to the change of the error.

[0030] Preferably, the temperature error calculation unit is connected to the main control panel, the PID parameter tuning unit is connected to the control strategy judgment unit, the feedforward control unit is connected to the main control panel and the power supply base plate, and the lag compensation control unit is connected to the main control panel and the power supply base plate.

[0031] Preferably, the data related to indoor air quality collected by the sensor unit includes PM2.5, PM10, TVOC, CO2, HCHO, temperature, and humidity.

[0032] Working principle: Data is collected through sensors, all input values are checked, and further processing is performed on the fuzzy logic block. The digital input data is fuzzified, which is completed using predefined input fuzzy sets. Fuzzy rules are used to infer the fuzzified data, and at the same time, centroid defuzzification is used to convert the fuzzy output into a crisp output, obtaining AQI 1 (C02 and HCHO), AQI2 (TVOC), AQI3 (PM2.5 and PM10), and AQI4 (temperature and humidity). Subsequently, the sum of the 4 clustering index values is obtained as the E IAQI value, and the opening and closing of the output system are determined by the EIAQI value. The EIAQI serves as an index reference for the automatic control system. When the seven-in-one air quality detector is used in conjunction with the three-in-one intelligent thermostat, the sensors in the air quality detector collect air quality parameters and send the collected data to the thermostat. The thermostat receives the data, processes it through the intelligent algorithm of the software, and controls the actuator to work, realizing the intelligent control of the product. Without manual control, the system can automatically adjust the air volume of the fresh air system according to the output indoor air quality grade signal. At the same time, based on the intelligent PID control air conditioning system, according to the error and the difference of the error between the actual indoor temperature and the set temperature. Taking summer cooling as an example, through 4 stages of indoor temperature change under cooling conditions, the intelligent PID control algorithm is adopted to select the PID parameters Kp, Ki, and Kd. The critical ratio method is used for parameter tuning to solve the problem of non-constant PID parameters, and feedforward control and system lag compensation control rules are added. According to the intelligent algorithm of the software, without manual control, the thermostat can automatically set the operation of the air conditioner according to the room temperature change. And the floor heating control system will control the start of the floor heating according to the rules. If the room temperature < the set temperature, the floor heating starts to heat; if the room temperature > the set temperature, the floor heating stops working. According to the set conditions of the software, without manual control, the thermostat can automatically control the operation of the floor heating.

[0033] The present invention provides an air quality monitoring and intelligent control system. It has the following beneficial effects:

[0034] 1. Through the design of a 5V isolated power supply circuit and measures such as an EMC protection circuit and a buck circuit, the high-voltage circuit is converted into a low-voltage power supply circuit in the present invention, realizing electrical isolation, safety protection, and voltage regulation, and improving the safety of the system.

[0035] 2. By adding two WI F I Bluetooth modules in the present invention, using voice control technology for voice recognition, remote wireless intelligent control via mobile phone APP and small programs, voice prompts, alarm prompts for mobile phone APP and small programs, functions such as voice query and timing, and adding relays and a RES485 communication module, integrated control of floor heating, fresh air, and air conditioning is realized, enabling the system to intelligently manage and control different devices, improving the overall efficiency and convenience, being multi-functional in one machine, and having strong functionality.

[0036] 3. The present invention is used in conjunction with a seven-in-one air quality detector to monitor air quality parameters in real time, and automatically adjust the operation of the fresh air system according to the indoor air quality level, ensuring indoor air quality safety, reflecting the function of intelligent linkage, and maximizing product performance.

[0037] 4. By adding intelligent algorithms such as fuzzy logic reasoning, intelligent PID control, and heating rule setting, the system can be intelligently and automatically controlled without manual operation, and can control the operation of fresh air, air conditioning, and floor heating according to the actual indoor situation, improving the intelligence level and efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is the framework diagram of the system of the present invention;

[0039] Figure 2 is the classification diagram of the AQI clustering index of the present invention;

[0040] Figure 3 is the framework diagram of the four stages of the present invention;

[0041] Figure 4 is the flow chart of the working principle of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] The technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0043] Embodiment:

[0044] Please refer to the appendix Figure 1 , the embodiment of the present invention provides an air quality monitoring and intelligent control system, including:

[0045] A power supply base plate for providing a stable power supply required by the system;

[0046] A main control panel for serving as an interface for users to interact with the system;

[0047] Two WI-FI Bluetooth modules, which are connected to the main control panel and external devices, are used to achieve communication connections between the system and external devices. Among them, Bluetooth is used to connect to the Xiaodu central control screen and Xiaodu speaker, and WI-FI is used to connect to the mobile phone APP and mini-program. The signal is received through a 2.4G wireless receiving module. Through the mobile phone APP and mini-program, the real-time indoor temperature and humidity values, other air quality parameter values, and indoor air quality grades can be viewed, and the floor heating, fresh air, and air conditioner can be remotely controlled wirelessly through the mobile phone APP and mini-program, and voice timing can be set. The timing time can be set through the mobile phone APP and mini-program. For example, flexible usage methods such as floor heating for 5 hours, fresh air at medium speed for 2 hours, and air conditioner cooling for 1 hour.

[0048] An air quality monitoring module, which is connected to the main control panel and is used to monitor and evaluate the indoor air quality;

[0049] An air conditioner system control module, which is connected to the main control panel and the power supply base plate and is used to control the operation of the air conditioner system to achieve the adjustment of the indoor temperature;

[0050] A floor heating control module, which is connected to the main control panel and is used to control the start and stop of the floor heating system to maintain the indoor temperature. If the room temperature < the set temperature, the floor heating starts; if the room temperature > the set temperature, the floor heating stops working.

[0051] The power supply base plate includes an EMC protection circuit, a rectification circuit with a voltage bias for the isolated switch power supply, a transformer, a step-down circuit, and a feedback circuit. The EMC protection circuit is used to protect the circuit from the influence of electromagnetic interference;

[0052] The rectification circuit with a voltage bias for the isolated switch power supply is used to convert alternating current into direct current and keep it stable;

[0053] The transformer and the step-down circuit are used to provide different voltage outputs;

[0054] The feedback circuit is used to detect the change in the transformer output load and ensure the stability of the output voltage by adjusting the control signal.

[0055] Specifically, the power circuit design part of the power supply base plate includes an EMC protection circuit, a rectification circuit with a voltage bias for the isolated switch power supply, a transformer, and a step-down circuit, including DC 5V and DC 3.3V. Among them, the relay drive circuit is powered by 5V, and the others are powered by 3.3V. In addition, by giving the transformer a feedback circuit, when the transformer output load changes, the feedback circuit can detect this change and ensure the stability of the output bias supply voltage by adjusting the control signal of the transformer.

[0056] The EMC protection circuit is connected to the main circuit board of the power supply base plate. The rectification circuit with the isolated switch power supply voltage bias is connected to the input end of the transformer. The feedback circuit is connected to the input end of the transformer.

[0057] The main control panel includes a touch button unit, an LCD screen and a backlight, and an RS485 communication circuit. The touch button unit is used for users to interact with the system.

[0058] The LCD screen and the backlight are used to be controlled by the MCU through the LCD driver chip to display the system status and information.

[0059] The RS485 communication circuit is used to connect to the air conditioner line panel to realize the control of the central air-conditioning system.

[0060] Specifically, there are 5 touch buttons on the main control panel, namely mode, up, down, switch and function. The 5 touch buttons on the temperature control panel are used to realize mode selection, value addition, value subtraction, switch and function setting. It can be voice-controlled. Voice commands such as "turn on floor heating for heating", "turn on fresh air at high speed", and "turn on air conditioner for cooling" can be issued for control. In addition to temperature control and harmful gas removal, it also has a timing function. The timing can be set through the touch buttons on the temperature control panel. The LCD screen is added with a backlight, and the MCU controls the LCD screen through the LCD driver chip. This temperature control panel is equipped with an RS485 communication circuit, and its interface is connected to the air conditioner line panel for controlling the central air-conditioning system. A bidirectional level conversion circuit is added between the MCU and the relay drive circuit for voltage conversion between 3.3V and 5V. There are 5 groups of relays in the execution circuit, and their corresponding interfaces are respectively connected to the high speed, medium speed and low speed of the fresh air system. The cold valve is connected to the fresh air system, and the hot valve is connected to the floor heating.

[0061] The touch button unit is connected to the control circuit board of the main control panel through a flexible cable. The LCD screen and the backlight are connected to the LCD driver chip of the main control panel through a flexible cable. The RS485 communication circuit is connected to the communication interface of the main control panel.

[0062] Please refer to the appendix Figures 2-4 , the air quality monitoring module includes a sensor unit, a fuzzy logic reasoning unit, an air quality index generation unit and a fuzzy logic controller. The sensor unit is used to collect data related to the indoor air quality.

[0063] The fuzzy logic reasoning unit is used to analyze the collected indoor air quality by using the fuzzy logic reasoning method.

[0064] The air quality index generation unit is used to calculate and generate the indoor air quality index according to the result of the fuzzy logic reasoning.

[0065] The fuzzy logic controller is used to identify the clustering index of the air quality index and conduct control based on the evaluation results of air quality parameters.

[0066] Specifically, the sensor unit is responsible for collecting data related to indoor air quality, including seven air quality parameters such as PM2.5, PM10, TVOC, CO2, HCHO, temperature, and humidity. These sensors provide real-time data support for the system by continuously monitoring the air quality parameters in the room. The fuzzy logic inference unit analyzes the indoor air quality data collected by the sensors using fuzzy logic inference methods. Through the set fuzzy logic rules and membership functions, the air quality parameters are classified and judged for further processing and control. The air quality index generation unit calculates and generates the indoor air quality index (AQI) based on the results of fuzzy logic inference. According to different air quality parameters and their weights, the level of indoor air quality is comprehensively evaluated and converted into specific index values. The fuzzy logic controller identifies the clustering index of the air quality index and conducts control based on the evaluation results of air quality parameters. According to the pre-set fuzzy rule base, the air quality index is classified and judged, and then corresponding control actions are triggered, such as turning on the fresh air system, alarm prompts, etc. In summary, the intelligent temperature controller of this air quality monitoring module uses fuzzy logic inference methods to analyze the indoor air and classify it according to the inference rules. Rule-based fuzzy logic is executed based on the data collected by the sensors, and the sensors collect seven air quality parameters in the air, namely PM2.5, PM10, TVOC, CO2, HCHO, temperature, and humidity. The seven detected data are combined for the judgment of air quality level classification. As attached Figure 2As shown, a fuzzy logic controller is used to identify the clustering index, generating Clustering Index I, Clustering Index II, Clustering Index III, and Clustering Index IV. The fuzzy logic inference method uses two types of membership functions, triangular and trapezoidal, to represent the intermediate level and high and low levels of the air quality parameter concentration respectively. The system input signal is the air quality parameters collected by the sensor, and the output signal is the indoor air quality index AQI. There are 4 clustering indexes, with 2 input membership function parameters and 1 output membership function for each index. The Sigma operator is used to statistically evaluate the air parameter concentration within the range of [0,1]. After allocating the fuzzy parameters and membership functions, the IF-THEN fuzzy rule base is displayed, and the clustering index contains 16 rules. When the sensor unit detects air quality parameters such as formaldehyde, CO2, PM2.5, PM10, TVOC, temperature, and humidity in the air, its signal collector will wirelessly send the detected data to the intelligent temperature controller. The intelligent temperature controller receives this data through a 2.4G wireless receiving module and displays it in real time on the temperature control panel, mobile phone APP, and mini-program. The air quality parameter values can be read in real time through the temperature control panel, mobile phone APP, and mini-program. When the air quality parameters exceed the standard, the temperature controller will automatically turn on the fresh air system according to the indoor air quality level. And it will give an alarm prompt through voice broadcast, mobile phone APP, and mini-program. According to the indoor air quality level, the temperature controller automatically adjusts the fresh air speed to maintain the safety of the indoor air quality and achieve the intelligent linkage of the product. The fresh air operation can also be adjusted through voice control, mobile phone APP, and mini-program.

[0067] The air-conditioning system control module includes a temperature error calculation unit, a control strategy judgment unit, a PID parameter tuning unit, a feedforward control unit, and a lag compensation control unit. The temperature error calculation unit is used to calculate the error between the actual indoor temperature and the set temperature.

[0068] The control strategy judgment unit is used to judge which control strategy to adopt according to the magnitude of the temperature error and the stage the system is in.

[0069] The PID parameter tuning unit is used to tune the parameters of the PID controller using the critical ratio method.

[0070] The feedforward control unit is used to output a signal to control the opening degree of the air-conditioning coil electric valve according to the change range of temperature and flow.

[0071] The lag compensation control unit is used to design a lag compensation control rule according to the time-delay characteristics of the system, so that the control variable is adjusted according to the change of the error.

[0072] Specifically, 1. The temperature error calculation unit and the control strategy judgment unit adopt different temperature control strategies for this system to control the temperature error within a limited range. Select the PID parameters K p 、Ki , K d , according to the error between the actual indoor temperature and the set temperature e = T A -T S , error difference △e=(e(k)-e(k-1)) / △t. Here TA is the actual indoor temperature, TS is the set temperature, and △t is the sampling time 15-20s.

[0073] Taking summer cooling as an example, it can be roughly divided into four stages, as shown in the following: Figure 3 shown.

[0074] Stage 1. Decreasing from room temperature to a stable state;

[0075] Stage 2. Steady state;

[0076] Stage 3. When there is interference, the indoor temperature drops;

[0077] Stage 4: When there is a disturbance, the indoor temperature rises.

[0078] 2. PID parameter tuning unit: Considering the instability of the selected PID parameters Kp, Ki, and Kd, the critical proportion method is proposed to be used for parameter tuning. The steps are as follows:

[0079] S1. Preselect a sampling period that is short enough for the system to operate. Here, the sampling time is 15-20s.

[0080] S2. Only add the proportional control link until the system shows critical oscillation in response to the input step, and record the proportional amplification factor and critical oscillation period at this time;

[0081] S3. Calculate the PID controller parameters by formula under a certain control degree.

[0082] The feedforward control unit outputs a signal to increase the opening of the air conditioning coil electric valve when the temperature and flow rate change greatly; otherwise, the electric valve opening is reduced.

[0083] Lag compensation control unit, due to the time lag of the system, the lag compensation control rules of the air conditioning system are designed as follows:

[0084] 3. When △e changes from negative to positive and e<0, reduce the control variable to make the temperature rise sharply due to hysteresis; when △e changes from negative to positive and e≥0, increase the control variable to make the error between the actual temperature and the set temperature continue to increase.

[0085] The temperature error calculation unit is connected to the main control panel, the PID parameter setting unit is connected to the control strategy judgment unit, the feedforward control unit is connected to the main control panel and the power base plate, and the lag compensation control unit is connected to the main control panel and the power base plate.

[0086] The sensor unit collects data related to indoor air quality, including PM2.5, PM10, TVOC, CO2, HCHO, temperature, and humidity.

[0087] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An air quality monitoring and intelligent control system, characterized in that, Comprising: A power supply base plate for providing a stable power supply required by the system; A main control panel for serving as an interface for users to interact with the system; Two WIFI Bluetooth modules, which are connected to the main control panel and external devices and are used to achieve communication connection between the system and external devices; An air quality monitoring module, which is connected to the main control panel and is used to monitor and evaluate the indoor air quality; An air-conditioning system control module, which is connected to the main control panel and the power supply base plate and is used to control the operation of the air-conditioning system to achieve adjustment of the indoor temperature; A floor heating control module, which is connected to the main control panel and is used to control the start and stop of the floor heating system to maintain the indoor temperature.

2. The air quality monitoring and intelligent control system according to claim 1, characterized in that, The power supply base plate includes an EMC protection circuit, a rectification circuit with isolated switch power supply voltage bias, a transformer, a buck circuit and a feedback circuit. The EMC protection circuit is used to protect the circuit from the influence of electromagnetic interference; The rectification circuit with isolated switch power supply voltage bias is used to convert alternating current into direct current and keep it stable; The transformer and the buck circuit are used to provide different voltage outputs; The feedback circuit is used to detect the change of the transformer output load and ensure the stability of the output voltage by adjusting the control signal.

3. An air quality monitoring and intelligent control system according to claim 2, characterized in that, The EMC protection circuit is connected to the main circuit board of the power supply base plate. The rectification circuit with isolated switch power supply voltage bias is connected to the input end of the transformer. The feedback circuit is connected to the input end of the transformer.

4. The air quality monitoring and intelligent control system according to claim 1, characterized in that The main control panel includes a touch button unit, an LCD screen and a backlight, and an RS485 communication circuit. The touch button unit is used for users to interact with the system; The LCD screen and the backlight are used to be controlled by the MCU through the LCD driver chip to display the system status and information; The RS485 communication circuit is used to connect to the air-conditioning line panel to achieve control of the central air-conditioning system.

5. An air quality monitoring and intelligent control system according to claim 4, characterized in that, The touch button unit is connected to the control circuit board of the main control panel through a flexible cable. The LCD screen and the backlight are connected to the LCD driver chip of the main control panel through a flexible cable. The RS485 communication circuit is connected to the communication interface of the main control panel.

6. The air quality monitoring and intelligent control system according to claim 1, characterized in that, The air quality monitoring module includes a sensor unit, a fuzzy logic reasoning unit, an air quality index generation unit and a fuzzy logic controller. The sensor unit is used to collect data related to the indoor air quality; The fuzzy logic reasoning unit is used to analyze the collected indoor air quality by using the fuzzy logic reasoning method; The air quality index generation unit is used to calculate and generate the indoor air quality index according to the result of the fuzzy logic reasoning; The fuzzy logic controller is used to identify the clustering index of the air quality index and perform control according to the evaluation result of the air quality parameters.

7. An air quality monitoring and intelligent control system according to claim 1, characterized in that, The air-conditioning system control module includes a temperature error calculation unit, a control strategy judgment unit, a PID parameter tuning unit, a feedforward control unit and a lag compensation control unit. The temperature error calculation unit is used to calculate the error between the actual indoor temperature and the set temperature; The control strategy judgment unit is used to judge which control strategy to adopt according to the magnitude of the temperature error and the stage in which the system is in; The PID parameter tuning unit is used to tune the parameters of the PID controller by using the critical ratio method; The feedforward control unit is used to output a signal to control the opening degree of the air-conditioning coil electric valve according to the change ranges of temperature and flow rate; The lag compensation control unit is used to design a lag compensation control rule according to the time-delay characteristics of the system, so that the control variable is adjusted according to the change of the error.

8. An air quality monitoring and intelligent control system according to claim 7, characterized in that, The temperature error calculation unit is connected to the main control panel, the PID parameter tuning unit is connected to the control strategy judgment unit, the feedforward control unit is connected to the main control panel and the power supply bottom plate, and the lag compensation control unit is connected to the main control panel and the power supply bottom plate.

9. The air quality monitoring and intelligent control system according to claim 6, characterized in that, The sensor unit collects indoor air quality-related data including PM2.5, PM10, TVOC, CO2, HCHO, temperature and humidity.

Images