An air conditioning control system with safety control based on FPGA

Abstract

This invention relates to the fields of intelligent services and data processing, specifically to an air-conditioning control system with safety control based on FPGA implementation. The system comprises a main card module, an I / O card module, a safety logic control module, a sensor module, and an actuator module. The main card module collects internal vehicle parameters via sensors and adjusts the air-conditioning equipment's operating strategy based on calculation and analysis. The I / O card module assumes control tasks in safety mode when the main card fails. The safety logic control module ensures that the air-conditioning system can maintain basic functions in safety mode. The sensor module senses environmental changes and converts and transmits signals. The actuator module converts the control system's output commands into physical controls for the air-conditioning equipment. The invention addresses the shortcomings of traditional air-conditioning systems in safety control, energy efficiency optimization, safety, and fault diagnosis, and enhances the air-conditioning's intelligence and user experience.

Description

Technical Field

[0001] The present invention relates to the fields of intelligent services and data processing, and in particular to an air-conditioning control system with safety control implemented based on FPGA. Background Art

[0002] The air-conditioning system in subway trains usually includes multiple functions such as temperature control, humidity control, and ventilation, and the normal implementation of these functions depends on the stable operation of the control system.

[0003] The control core of an air conditioning system typically consists of a main card and multiple I / O cards. The main card is responsible for the entire air conditioning system's logical operations, command processing, data analysis, and communication with the train control and management system. The I / O cards, on the other hand, manage signal input and output, transmitting commands from the main card to the air conditioning equipment's execution unit and acquiring environmental data from sensor modules.

[0004] However, during subway train operation, the master card may fail due to malfunction, damage, or power outage, causing a complete loss of control over the air conditioning system. If the backup control system cannot be restored or activated in a timely manner, the air conditioning equipment will not function properly, affecting passenger comfort and potentially causing serious safety issues.

[0005] Traditional air conditioning control systems typically rely on a single master card for operation. A failure of this card can paralyze the entire system. Therefore, ensuring the system's basic functionality in the event of a master card failure, particularly maintaining optimal temperature and humidity levels during critical moments, presents a pressing technical challenge. Summary of the Invention

[0006] In view of the above problems, the present invention aims to provide an air-conditioning control system with safety control implemented based on FPGA to solve the problems raised in the above background technology.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] The present invention provides an air-conditioning control system with safety control implemented based on FPGA, including a main card module, an IO card module, a safety logic control module, a sensor module and an actuator module. The main card module collects the temperature, humidity, pressure and flow parameters inside the car through sensors, determines the operating mode of the air-conditioning system based on calculation and analysis, adjusts the operating strategy of the air-conditioning equipment, and ensures passenger comfort; the IO card module assumes the control task in the safety mode when the main card fails, and can quickly respond to input changes to ensure the stability of the system; the safety logic control module ensures that the air-conditioning system can still maintain basic functions in the safety mode to prevent the system from being completely paralyzed; the sensor module senses changes in the environment, converts relevant information into electrical signals, and then outputs them to the control system in the form of analog or digital signals; the actuator module converts the instructions output by the control system into physical control of the air-conditioning equipment, ensuring that the system can make appropriate responses according to environmental changes.

[0009] Furthermore, the main card module collects the temperature, humidity, pressure, and flow parameters inside the car through sensors, and determines the operating mode of the air-conditioning system based on calculation and analysis. According to the acceleration, deceleration, and stop operation status of the train, the operating strategy of the air-conditioning equipment is adjusted to ensure passenger comfort while improving energy utilization efficiency. The main card module communicates with the train control and management system, receives instructions from the overall train control system, and adjusts the operating mode of the air-conditioning according to the instructions. The main card module manages all air-conditioning-related logical controls, including the start and stop and speed regulation of the fan, the operating mode switching of the compressor, and the status management of the condenser and evaporator. It uses computer algorithms to determine when to start and close the solenoid valve and control the flow of refrigerant to achieve control decisions.

[0010] Furthermore, the main card module formulates the control strategy of the air conditioning system and implements the control decision, including the temperature control algorithm and the safety control algorithm. For the temperature control algorithm, the target temperature of the air conditioning system is set to , the actual indoor temperature is , the external ambient temperature is , the control target of the air conditioning system is based on and Adjust the cooling and heating capacity of the air conditioner based on the temperature difference between:

[0011] ,in is the air mass flow rate, is the specific heat capacity of air, is the cooling power of the air conditioning system, is the heating power of the air conditioning system, is the ambient heat load, The actual indoor temperature change rate, in order to achieve accurate temperature regulation, the air conditioning system monitors the indoor temperature and set temperature , the error between them is used for feedback control, and the temperature error is defined as :

[0012]

[0013] Temperature error This directly affects the air conditioner's control strategy. Within different error ranges, the air conditioner's cooling or heating capacity will be dynamically adjusted. To ensure a smooth transition and avoid over-adjustment, the error adjustment adopts a dynamic weighting mechanism:

[0014]

[0015] in: is the control signal, 、 is the dynamic weight coefficient, which represents the influence of temperature error and error change rate on the control signal. is the rate of change, further, we have: in, , is the initial weight coefficient, , , , To adjust the parameters and control the dynamic response strength of the weight coefficient, when the temperature error is large, the system will increase The value of makes the control signal more sensitive to the error; when the temperature changes rapidly, increasing The adjustment of the error change rate can be enhanced to avoid over-response. In order to ensure the stability of the temperature control system, the stability condition of the system is introduced. The temperature dynamic equation of the system is: in,( , , ) is the external environmental disturbance, is wind speed, is humidity. According to Lyapunov stability theory, if the system satisfies , then the temperature error of the system Will tend to zero, ensuring the stability of temperature control.

[0016] Furthermore, the safety control algorithm can timely perform protective shutdown or alarm under abnormal circumstances to prevent the air-conditioning equipment from overloading, overvoltage, and overheating safety hazards. When the current sensor detects that the current of the air-conditioning equipment exceeds the safe range, the system will automatically cut off the power supply, stop the compressor, and trigger an alarm signal to prompt the user to check the equipment. The pressure sensor will also monitor the pressure changes in the air-conditioning system in real time. When the system has an overvoltage or low-pressure fault, the system will automatically adjust the operating status of the compressor, or even directly shut down the equipment in extreme cases, thereby avoiding damage or safety accidents. Assume that the system state is represented by the state vector Expressed as, the system state dynamic equation Expressed as: in, is the system state vector, is the actual humidity, is the rate of change of actual humidity, 、 、 Describe the state coupling relationship, the impact of control input on the state, and the propagation of external disturbances respectively. To ensure system safety, it is necessary to optimize the state under the following safety constraints: , is the safety range of the state, To control the safety range of the signal, there are constraints: in, Lower temperature limit, is the upper temperature limit, is the lower limit of humidity, The upper limit of humidity, is the lower power limit, is the power limit, in order to cope with environmental disturbances ( , , ) uncertainty, the algorithm designs a robust controller to generate control inputs in real time : , is the regularization factor. Considering the nonlinear relationship between the control input and the state of the air-conditioning system, the robust controller uses nonlinear optimization technology to solve the state optimization problem under the safety constraints. The objective function is designed as a multi-objective weighted form: in, , , is the target weight coefficient, which is used to balance the temperature, humidity and power targets. The objective function and constraints are integrated into a Lagrangian function through the Lagrangian multiplier method: in, is the Lagrangian operator, is the Lagrangian function, The inequality function vector used to describe the safety constraints satisfies the KKT conditions as follows: .

[0017] Furthermore, the IO card module assumes the control tasks in the safe mode when the main card fails. The FPGA chip on the IO card processes temperature, humidity, pressure, and flow parameters. Under normal working conditions, the IO card acts as the execution unit of the main card and performs air-conditioning control tasks according to the instructions sent by the main card, including turning on and off the compressor, adjusting the inverter frequency, and switching the solenoid valve status. The control signal is forwarded to the corresponding actuator through the IO card. When the main card fails, the IO card will not detect the heartbeat signal of the main card and will automatically enter the safe mode. In the safe mode, the FPGA controls the output according to the current input signal based on the preset truth table logic. Since the FPGA's logic control is based on hardware implementation, the IO card can quickly respond to input changes in the safe mode to ensure the stability of the system.

[0018] Furthermore, the IO card has electrical isolation and anti-interference capabilities to adapt to the complex electromagnetic environment of subway trains: the FPGA has redundant logic inside. When the input signal is abnormal or short-term interference occurs, the FPGA can automatically filter the abnormal signal to avoid misoperation. In addition, the IO card has a fault detection function to monitor whether the actuator is responding normally to control instructions. If an abnormality is found, the FPGA will adopt corresponding safety strategies. The safety strategies include: stopping the abnormal actuator or switching to the default safety state to prevent system damage. Since public network connection is not allowed on the train, all inputs and outputs of the IO card are connected to the main card and external devices via wired mode.

[0019] Furthermore, the safety logic control module ensures that the air-conditioning system can still maintain basic functions in safety mode to prevent the system from being completely paralyzed. The FPGA runs on the IO card. When the main card is working normally, the FPGA acts as the execution unit for signal processing and performs logical operations and signal transmission according to the instructions issued by the main card to ensure that each actuator operates according to the predetermined logic. In the event of failure of the main card, the safety logic control module must work independently. It will first determine whether the main card is operating normally by detecting the heartbeat signal of the main card. Once the heartbeat signal of the main card is not received within the set time window, the FPGA will switch to safety mode and take over the basic control tasks of the air-conditioning system. In safety mode, the FPGA relies on a predefined truth table for logic control. Since the truth table is fixed, the control logic of the FPGA will not be interfered with by the external environment and can maintain stable operation even under extreme conditions.

[0020] Furthermore, the sensor module includes a temperature sensor, a humidity sensor, a pressure sensor, and a flow sensor, which sense changes in the environment, convert relevant information into electrical signals, and then output them to the control system in the form of analog or digital signals.

[0021] Furthermore, the actuator module converts the instructions output by the control system into physical control of the air-conditioning equipment to ensure that the system can respond appropriately to environmental changes. The actuator module includes a compressor controller, a fan controller, a solenoid valve, a heater, and an inverter controller. After receiving the signal from the control system, the actuator will adjust the working state of the equipment according to the instructions to achieve the environmental control effect.

[0022] The beneficial effects of the present invention are as follows: the main card module collects the temperature, humidity, pressure, and flow parameters inside the car through sensors, and determines the operating mode of the air-conditioning system based on calculation and analysis, thereby optimizing the operating strategy of the air-conditioning equipment to ensure passenger comfort.

[0023] The safety logic control module ensures the air conditioning system maintains basic functionality in safe mode, preventing complete system failure. When the main card is operating normally, the FPGA, acting as the signal processing execution unit, is responsible for logical operations and signal transmission, ensuring that each actuator operates according to the predefined logic. If the main card fails, the safety logic control module operates independently, detecting the main card's heartbeat signal to determine its operating status. If the main card experiences an anomaly, the FPGA takes over basic control of the air conditioning system, relying on a predefined truth table for logical control. Because this control logic is unaffected by the external environment, the system maintains stable operation even under extreme conditions. To adapt to the complex electromagnetic environment of subway trains, the I / O card features electrical isolation and interference immunity, along with built-in redundant logic that effectively filters short-term interference from input signals to prevent misoperation. Furthermore, the IO card includes fault detection, monitoring whether actuators are responding properly to control commands. If an anomaly is detected, the FPGA implements appropriate safety measures, such as stopping the faulty actuator or switching to a default safe state, to prevent system damage. Because public network connections are not permitted on trains, all input and output connections to the main card and external devices are wired to ensure secure and reliable data transmission.

[0024] This paper also proposes temperature control and safety control algorithms. Robust control theory is employed in safety control, incorporating the uncertainty of environmental disturbances and the multivariable nature of the system to formulate a robust optimization problem. By solving this robust optimization problem, the controller can adjust control inputs in real time in the face of complex external disturbances, ensuring safe and stable system operation under all circumstances. This algorithm innovatively applies Lyapunov stability theory to the safety control of air conditioning systems. By constructing appropriate Lyapunov functions, it analyzes and ensures that the system maintains a stable state in the face of external disturbances. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The invention is further illustrated by the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the invention. A person skilled in the art can obtain other drawings based on the following drawings without making any creative effort.

[0026] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] See also Figure 1 , the present invention is further described in conjunction with the following examples.

[0029] See also Figure 1 The present invention aims to provide an air-conditioning control system with safety control based on FPGA, including a main card module, an IO card module, a safety logic control module, a sensor module and an actuator module. The main card module collects the temperature, humidity, pressure and flow parameters inside the car through sensors, determines the operation mode of the air-conditioning system based on calculation and analysis, adjusts the operation strategy of the air-conditioning equipment, and ensures passenger comfort; the IO card module assumes the control task in the safety mode when the main card fails, and can quickly respond to input changes to ensure the stability of the system; the safety logic control module ensures that the air-conditioning system can still maintain basic functions in the safety mode to prevent the system from being completely paralyzed; the sensor module converts the relevant information into electrical signals by sensing changes in the environment, and then outputs it to the control system in the form of analog or digital signals; the actuator module converts the instructions output by the control system into physical control of the air-conditioning equipment to ensure that the system can make appropriate responses according to environmental changes.

[0030] Specifically, the main card module collects the temperature, humidity, pressure, and flow parameters inside the car through sensors, determines the operating mode of the air-conditioning system based on calculation and analysis, and adjusts the operating strategy of the air-conditioning equipment according to the acceleration, deceleration, and stop status of the train to ensure passenger comfort while improving energy utilization efficiency. The main card module communicates with the train control and management system, receives instructions from the train's overall control system, and adjusts the operating mode of the air-conditioning according to the instructions.

[0031] Operational modes include reducing power consumption in emergency situations or increasing cooling capacity during high occupancy conditions.

[0032] Specifically, the main card module manages all air-conditioning-related logic controls, including fan start / stop and speed regulation, compressor operating mode switching, and condenser and evaporator status management. It uses computer algorithms to determine when to start and close the solenoid valve and control the flow of refrigerant to implement control decisions.

[0033] Specifically, the main card module formulates the control strategy of the air conditioning system and implements the control decision, including the temperature control algorithm and the safety control algorithm. For the temperature control algorithm, the target temperature of the air conditioning system is set to , the actual indoor temperature is , the external ambient temperature is , the control target of the air conditioning system is based on and Adjust the cooling and heating capacity of the air conditioner based on the temperature difference between: ,in is the air mass flow rate, is the specific heat capacity of air, is the cooling power of the air conditioning system, is the heating power of the air conditioning system, is the ambient heat load, The actual indoor temperature change rate, in order to achieve accurate temperature regulation, the air conditioning system monitors the indoor temperature and set temperature , the error between them is used for feedback control, and the temperature error is defined as : Temperature error This directly affects the air conditioner's control strategy. Within different error ranges, the air conditioner's cooling or heating capacity will be dynamically adjusted. To ensure a smooth transition and avoid over-adjustment, the error adjustment adopts a dynamic weighting mechanism: in: is the control signal, 、 is the dynamic weight coefficient, which represents the influence of temperature error and error change rate on the control signal. Further for the rate of change, we have: in, , is the initial weight coefficient, , , , To adjust the parameters and control the dynamic response strength of the weight coefficient, when the temperature error is large, the system will increase The value of makes the control signal more sensitive to the error; when the temperature changes rapidly, increasing The adjustment of the error change rate can be enhanced to avoid over-response. In order to ensure the stability of the temperature control system, the stability condition of the system is introduced. The temperature dynamic equation of the system is: in,( , , ) is the external environmental disturbance, is wind speed, is humidity. According to Lyapunov stability theory, if the system satisfies , then the temperature error of the system Will tend to zero, ensuring the stability of temperature control.

[0034] Specifically, the safety control algorithm can perform protective shutdown or alarm in time under abnormal circumstances to prevent the air-conditioning equipment from overloading, overvoltage, and overheating safety hazards. When the current sensor detects that the current of the air-conditioning equipment exceeds the safe range, the system will automatically cut off the power supply, stop the compressor, and trigger an alarm signal to prompt the user to check the equipment. The pressure sensor will also monitor the pressure changes in the air-conditioning system in real time. When the system has an overvoltage or low-pressure fault, the system will automatically adjust the operating status of the compressor, or even directly shut down the equipment in extreme cases, thereby avoiding damage or safety accidents. Assume that the system state is represented by the state vector The system state dynamic equation is expressed as Expressed as: in, is the system state vector, is the actual humidity, is the rate of change of actual humidity, 、 、 Describe the state coupling relationship, the impact of control input on the state, and the propagation of external disturbances respectively. To ensure system safety, it is necessary to optimize the state under the following safety constraints: , is the safety range of the state, To control the safety range of the signal, there are constraints: in, is the lower limit of temperature, is the upper temperature limit, is the lower limit of humidity, The upper limit of humidity, is the lower power limit, is the power limit, in order to cope with environmental disturbances ( , , ) uncertainty, the algorithm designs a robust controller to generate control inputs in real time : , is the regularization factor. Considering the nonlinear relationship between the control input and the state of the air-conditioning system, the robust controller uses nonlinear optimization technology to solve the state optimization problem under the safety constraints. The objective function is designed as a multi-objective weighted form: in, , , is the target weight coefficient, which is used to balance the temperature, humidity and power targets. The objective function and constraints are integrated into a Lagrangian function through the Lagrangian multiplier method: in, is the Lagrangian operator, is the Lagrangian function, The inequality function vector used to describe the safety constraints satisfies the KKT conditions as follows: .

[0035] Specifically, the IO card module assumes control tasks in safety mode when the main card fails. The FPGA chip on the IO card processes temperature, humidity, pressure, and flow parameters. Under normal working conditions, the IO card serves as the execution unit of the main card and performs air conditioning control tasks according to the instructions sent by the main card, including turning on and off the compressor, adjusting the inverter frequency, and switching the solenoid valve status. The control signal is forwarded to the corresponding actuator through the IO card.

[0036] Specifically, when the main card fails, the IO card cannot detect the heartbeat signal of the main card and automatically enters the safe mode.

[0037] Specifically, in safe mode, the FPGA controls the output according to the current input signal based on the preset truth table logic. For example, when the temperature sensor detects that the temperature is too high, the FPGA will start the compressor and fan according to the truth table to reduce the temperature. If the temperature is moderate, the system will maintain a low-power operating state.

[0038] Specifically, since the logic control of the FPGA is implemented based on hardware, the IO card can quickly respond to input changes in safe mode to ensure system stability.

[0039] Specifically, the IO card has electrical isolation and anti-interference capabilities to adapt to the complex electromagnetic environment of subway trains: the FPGA is equipped with redundant logic inside. When the input signal is abnormal or short-term interference occurs, the FPGA can automatically filter the abnormal signal to avoid misoperation.

[0040] Specifically, the IO card has a fault detection function to monitor whether the actuator responds normally to the control instructions. If an abnormality is found, the FPGA will adopt the corresponding safety strategy.

[0041] Specifically, the safety strategy includes stopping abnormal actuators or switching to the default safety state to prevent system damage. Since public network connections are not allowed on trains, all inputs and outputs of the IO card are connected to the main card and external devices via wired connections.

[0042] Specifically, the safety logic control module ensures that the air-conditioning system can still maintain basic functions in safety mode to prevent the system from being completely paralyzed. The FPGA runs on the IO card. When the main card is working normally, the FPGA acts as the execution unit for signal processing, performing logical operations and signal transmission according to the instructions issued by the main card to ensure that each actuator operates according to the predetermined logic. In the event of failure of the main card, the safety logic control module must work independently.

[0043] Specifically, the safety logic control module will first determine whether the main card is operating normally by detecting the heartbeat signal of the main card. Once the heartbeat signal of the main card is not received within the set time window, the FPGA will switch to safety mode and take over the basic control tasks of the air-conditioning system.

[0044] Specifically, in safe mode, the FPGA relies on a predefined truth table for logic control. Since the truth table is fixed, the FPGA's control logic will not be disturbed by the external environment and can maintain stable operation even under extreme conditions.

[0045] Specifically, after entering the safe mode, the FPGA will decide whether to start the compressor based on the current input signal, such as the data from the temperature sensor, and adjust the output frequency of the inverter according to the set logic to control the speed of the fan, thereby achieving basic regulation of the vehicle compartment temperature.

[0046] Specifically, in addition, the FPGA manages the switching state of the solenoid valve to ensure that the flow direction of the refrigerant meets the preset logical requirements, thereby ensuring that the system can maintain the minimum cooling or heating function.

[0047] Specifically, in safe mode, the FPGA only performs the most basic logical judgments and does not perform advanced data analysis or prediction. This simplified design helps improve system reliability while reducing FPGA hardware resource consumption.

[0048] Specifically, the sensor module includes a temperature sensor, a humidity sensor, a pressure sensor, and a flow sensor. By sensing changes in the environment, it converts relevant information into electrical signals, and then outputs them to the control system in the form of analog or digital signals.

[0049] Specifically, the actuator module converts the instructions output by the control system into physical control of the air-conditioning equipment to ensure that the system can respond appropriately to environmental changes. The actuator module includes a compressor controller, a fan controller, a solenoid valve, a heater, and an inverter controller. After receiving the signal from the control system, the actuator will adjust the working state of the equipment according to the instructions to achieve the environmental control effect.

[0050] Specifically, the compressor controller has the functions of cooling and heating, and the opening and closing of the compressor controller directly affects the cooling and heating efficiency of the air-conditioning system.

[0051] Specifically, the fan controller adjusts the speed and start and stop of the fan. By controlling the speed of the fan, the intensity of the air circulation can be adjusted, thereby affecting the temperature and humidity distribution in the room.

[0052] Specifically, the solenoid valve regulates the flow of refrigerant, and the system can accurately regulate the flow of refrigerant in different working modes to achieve the best cooling or heating effect.

[0053] Specifically, the inverter controller achieves flexible adjustment of the compressor by changing the operating frequency of the compressor, thereby controlling the cooling or heating effect of the air-conditioning system, avoiding energy waste and equipment loss caused by frequent starting and stopping of the compressor.

[0054] The beneficial effects of the present invention are as follows: the main card module collects the temperature, humidity, pressure, and flow parameters inside the car through sensors, and determines the operating mode of the air-conditioning system based on calculation and analysis, thereby optimizing the operating strategy of the air-conditioning equipment to ensure passenger comfort.

[0055] The safety logic control module ensures the air conditioning system maintains basic functionality in safe mode, preventing complete system failure. When the main card is operating normally, the FPGA, acting as the signal processing execution unit, is responsible for logical operations and signal transmission, ensuring that each actuator operates according to the predefined logic. If the main card fails, the safety logic control module operates independently, detecting the main card's heartbeat signal to determine its operating status. If the main card experiences an anomaly, the FPGA takes over basic control of the air conditioning system, relying on a predefined truth table for logical control. Because this control logic is unaffected by the external environment, the system maintains stable operation even under extreme conditions. To adapt to the complex electromagnetic environment of subway trains, the I / O card features electrical isolation and interference immunity, along with built-in redundant logic that effectively filters short-term interference from input signals to prevent misoperation. Furthermore, the IO card includes fault detection, monitoring whether actuators are responding properly to control commands. If an anomaly is detected, the FPGA implements appropriate safety measures, such as stopping the faulty actuator or switching to a default safe state, to prevent system damage. Because public network connections are not permitted on trains, all input and output connections to the main card and external devices are wired to ensure secure and reliable data transmission.

[0056] This paper also proposes temperature control and safety control algorithms. Robust control theory is employed in safety control, incorporating the uncertainty of environmental disturbances and the multivariable nature of the system to formulate a robust optimization problem. By solving this robust optimization problem, the controller can adjust control inputs in real time in the face of complex external disturbances, ensuring safe and stable system operation under all circumstances. This algorithm innovatively applies Lyapunov stability theory to the safety control of air conditioning systems. By constructing appropriate Lyapunov functions, it analyzes and ensures that the system maintains a stable state in the face of external disturbances.

[0057] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to replace some of the technical features therein. Any modifications, replacements, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An air conditioning control system based on FPGA-based safety control, including a main card module, an IO card module, a safety logic control module, a sensor module, and an actuator module. The main card module collects the temperature, humidity, pressure, and flow parameters inside the vehicle compartment through sensors, determines the operating mode of the air conditioning system based on calculation and analysis, and adjusts the operating strategy of the air conditioning equipment; the IO card module assumes the control task in the safety mode when the main card fails, and can quickly respond to input changes; the safety logic control module ensures that the air conditioning system can still maintain basic functions in the safety mode; the sensor module senses changes in the environment and converts the relevant information into electrical signals, which are then output to the control system in the form of analog or digital signals; the actuator module converts the instructions output by the control system into physical control of the air conditioning equipment; the main card module collects the temperature, humidity, pressure, and flow parameters inside the vehicle compartment through sensors The temperature, humidity, pressure, and flow parameters of the entire train are calculated and analyzed to determine the operating mode of the air-conditioning system. According to the acceleration, deceleration, and stop status of the train, the operating strategy of the air-conditioning equipment is adjusted to ensure passenger comfort and improve energy efficiency. The main card module communicates with the train control and management system, receives instructions from the overall train control system, and adjusts the operating mode of the air-conditioning according to the instructions. The main card module manages all air-conditioning-related logical controls, including the start and stop and speed regulation of the fan, the operating mode switching of the compressor, and the status management of the condenser and evaporator. It uses computer algorithms to determine when to start and close the solenoid valve and control the flow of refrigerant to achieve control decisions. The main card module formulates the control strategy of the air-conditioning system and implements control decisions, including temperature control algorithms and safety control algorithms. For the temperature control algorithm, the target temperature of the air-conditioning system is set to , the actual indoor temperature is , the external ambient temperature is , the control objective of the air conditioning system is based on and Adjust the cooling and heating capacity of the air conditioner based on the temperature difference between: ,in is the air mass flow rate, is the specific heat capacity of air, is the cooling power of the air conditioning system, is the heating power of the air conditioning system, is the ambient heat load, The actual indoor temperature change rate, in order to achieve accurate temperature regulation, the air conditioning system monitors the indoor temperature and set temperature , the error between them is used for feedback control, and the temperature error is defined as : Temperature error This directly affects the air conditioner's control strategy. Within different error ranges, the air conditioner's cooling or heating capacity will be dynamically adjusted. To ensure a smooth transition and avoid over-adjustment, the error adjustment adopts a dynamic weighting mechanism: in: u(t) is the control signal, 、 is the dynamic weight coefficient, which represents the influence of temperature error and error change rate on the control signal. is the rate of change Furthermore, there are: in, , is the initial weight coefficient, , , , To adjust the parameters and control the dynamic response strength of the weight coefficient, when the temperature error is large, the system will increase The value of makes the control signal more sensitive to the error; when the temperature changes quickly, increasing The adjustment of the error change rate can be enhanced to avoid over-response. In order to ensure the stability of the temperature control system, the stability condition of the system is introduced. The temperature dynamic equation of the system is: in, For external environmental disturbances, is wind speed, is humidity. According to Lyapunov stability theory, if the system satisfies , then the temperature error of the system Will tend to zero, ensuring the stability of temperature control.

2. The air conditioning control system with safety control based on FPGA according to claim 1, characterized in that: The safety control algorithm can perform protective shutdown or alarm in time under abnormal circumstances to prevent the air-conditioning equipment from overloading, overvoltage, and overheating safety hazards. When the current sensor detects that the current of the air-conditioning equipment exceeds the safe range, the system will automatically cut off the power supply, stop the compressor, and trigger an alarm signal to prompt the user to check the equipment. The pressure sensor will also monitor the pressure changes in the air-conditioning system in real time. When the system has an overvoltage or low-pressure fault, the system will automatically adjust the operating status of the compressor, or even directly shut down the equipment in extreme cases, thereby avoiding damage or safety accidents. Assuming that the system state is represented by the state vector x(t), the system state dynamic equation is Expressed as: in, is the system state vector, is the actual humidity, is the rate of change of actual humidity, 、 、 Describe the state coupling relationship, the impact of control input on the state, and the propagation of external disturbances respectively. To ensure system safety, it is necessary to optimize the state under the following safety constraints: is the safety range of the state, To control the safety range of the signal, there are constraints: in, is the lower limit of temperature, is the upper temperature limit, is the lower limit of humidity, The upper limit of humidity, is the lower power limit, As the power limit, in order to cope with environmental disturbances The algorithm designs a robust controller to generate control input in real time. : is the regularization factor. Considering the nonlinear relationship between the control input and the state of the air-conditioning system, the robust controller uses nonlinear optimization technology to solve the state optimization problem under the safety constraints. The objective function is designed as a multi-objective weighted form: in, , , is the target weight coefficient, which is used to balance the temperature, humidity and power targets. The objective function and constraints are integrated into a Lagrangian function through the Lagrangian multiplier method: in, is the Lagrangian operator, is the Lagrangian function, The inequality function vector used to describe the safety constraints satisfies the KKT conditions as follows: 。 3. The air-conditioning control system with safety control based on FPGA according to claim 1, characterized in that: The IO card module assumes control tasks in safe mode when the main card fails. The FPGA chip on the IO card processes temperature, humidity, pressure, and flow parameters. Under normal working conditions, the IO card serves as the execution unit of the main card and performs air conditioning control tasks according to the instructions sent by the main card, including turning on and off the compressor, adjusting the inverter frequency, and switching the solenoid valve status. The control signal is forwarded to the corresponding actuator through the IO card. When the main card fails, the IO card will not detect the heartbeat signal of the main card and will automatically enter safe mode. In safe mode, the FPGA controls the output according to the current input signal based on the preset truth table logic. Since the FPGA's logical control is implemented based on hardware, the IO card can quickly respond to input changes in safe mode to ensure system stability.

4. The air-conditioning control system with safety control based on FPGA according to claim 3, characterized in that: The IO card features electrical isolation and anti-interference capabilities to adapt to the complex electromagnetic environment of subway trains. The FPGA has internal redundant logic. When the input signal is abnormal or short-term interference occurs, the FPGA can automatically filter the abnormal signal to avoid misoperation. The IO card also has a fault detection function to monitor whether the actuator is responding normally to control instructions. If an anomaly is detected, the FPGA will implement appropriate safety strategies, including stopping the abnormal actuator or switching to the default safety state to prevent system damage. Since public network connections are not allowed on trains, all inputs and outputs of the IO card are connected to the main card and external devices via wired connections.

5. The air-conditioning control system with safety control based on FPGA according to claim 1, characterized in that: The safety logic control module ensures that the air-conditioning system can still maintain basic functions in safety mode to prevent the system from being completely paralyzed. The FPGA runs on the IO card. When the main card is operating normally, the FPGA acts as the execution unit for signal processing, performing logical operations and signal transmission according to the instructions issued by the main card to ensure that each actuator operates according to the predetermined logic. In the event of a main card failure, the safety logic control module must work independently. It will first determine whether the main card is operating normally by detecting the heartbeat signal of the main card. Once the heartbeat signal of the main card is not received within the set time window, the FPGA will switch to safety mode and take over the basic control tasks of the air-conditioning system. In safety mode, the FPGA relies on a predefined truth table for logic control. Since the truth table is fixed, the control logic of the FPGA will not be interfered with by the external environment and can maintain stable operation even under extreme conditions.

6. The air-conditioning control system with safety control based on FPGA according to claim 1, characterized in that: The sensor module includes temperature sensors, humidity sensors, pressure sensors, and flow sensors. By sensing changes in the environment, it converts relevant information into electrical signals, and then outputs them to the control system in the form of analog or digital signals.

7. The air conditioning control system with safety control based on FPGA according to claim 1, characterized in that: The actuator module converts the instructions output by the control system into physical control of the air-conditioning equipment, ensuring that the system can respond appropriately to environmental changes. The actuator module includes a compressor controller, a fan controller, a solenoid valve, a heater, and an inverter controller. After receiving the signal from the control system, the actuator will adjust the working state of the equipment according to the instructions to achieve the environmental control effect.

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