Air conditioner control system for realizing safety control based on FPGA (Field Programmable Gate Array)

Abstract

The invention relates to the field of intelligent service and data processing, in particular to an air conditioner control system for safety control based on an FPGA (Field Programmable Gate Array), which comprises a main card module, an IO (Input / Output) card module, a safety logic control module, a sensor module and an actuator module, adjusting an operation strategy of the air conditioning equipment based on calculation and analysis; the IO card module undertakes a control task in a safety mode when the main card fails; the safety logic control module ensures that the air conditioning system can still maintain basic functions in a safety mode; the sensor module converts and transmits a signal by sensing the change of an environment; the actuator module converts an instruction output by the control system into physical control over the air conditioner equipment. The method has the beneficial effects that the defects of a traditional air conditioner system in the aspects of safety control, energy efficiency optimization, safety and fault diagnosis are overcome, and the intelligent degree of the air conditioner and the user experience are improved.

Description

Technical Field

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

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

[0003] The control core of the air-conditioning system usually consists of a main card and multiple IO cards. The main card is responsible for the logical operation, instruction processing, data analysis of the entire air-conditioning system, and communication with the train control and management system. The IO card is responsible for the management of signal input and output. It transmits the instructions issued by the main card to the execution part of the air-conditioning equipment and obtains environmental data from the sensor module.

[0004] However, during the operation of the subway train, the main card may fail due to reasons such as faults, damages, or power outages, resulting in the interruption of the control of the entire air-conditioning system. At this time, if the backup control system cannot be restored or enabled in time, the air-conditioning equipment will not work properly, which will affect the comfort of passengers and may even cause serious safety problems.

[0005] Traditional air-conditioning control systems usually rely on a single main card for operation. Once the main card fails, the entire system may be paralyzed. Therefore, how to ensure the basic functions of the air-conditioning system when the main card fails, especially to maintain the appropriate range of temperature and humidity at critical moments, has become an urgent technical problem to be solved. Summary of the Invention

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

[0007] The object of the present invention is achieved by the following technical solutions:

[0008] The present invention provides an air-conditioning control system for safety control implemented based on FPGA, which includes 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 temperature, humidity, pressure, and flow parameters inside the carriage through sensors, determines the operating mode of the air-conditioning system based on calculations and analyses, adjusts the operating strategy of the air-conditioning equipment, and ensures passenger comfort. The IO card module undertakes the control tasks in the safety mode when the main card fails, can quickly respond to input changes, and 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 and prevents the system from complete paralysis. The sensor module senses environmental changes, 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 temperature, humidity, pressure, and flow parameters inside the carriage through sensors, determines the operating mode of the air-conditioning system based on calculations and analyses, adjusts the operating strategy of the air-conditioning equipment according to the acceleration, deceleration, and stop operation states of the train, ensures passenger comfort, and improves energy utilization efficiency at the same time. 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 logic controls, including the start, stop, and speed regulation of the fan, the switching of the compressor operating mode, the state management of the condenser and evaporator, and judges when to start and close the solenoid valve through computer algorithms to control the refrigerant flow to achieve control decisions.

[0010] Furthermore, the main card module formulates the control strategy of the air-conditioning system and realizes 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 as , the actual indoor temperature is , the external environmental temperature is , and the control objective of the air-conditioning system is to adjust the cooling and heating capacity of the air-conditioning according to the temperature difference between and :

[0011] , where is the air mass flow rate, is the specific heat capacity of the air, is the cooling power of the air-conditioning system, is the heating power of the air-conditioning system, is the environmental heat load, is the actual indoor temperature change rate. To achieve precise temperature regulation, the air-conditioning system monitors the indoor temperature and the set temperature , feedback control is performed based on the error between them, and the temperature error is defined as :

[0012]

[0013] Temperature error will directly affect the control strategy of the air conditioner. Within different error ranges, the cooling or heating capacity of the air conditioner will be dynamically adjusted. To achieve a smooth transition and avoid over-regulation, a dynamic weighting mechanism is adopted for error adjustment:

[0014]

[0015] Where: is the control signal, , are the dynamic weight coefficients, indicating the influence of the temperature error and the error change rate on the control signal, is the change rate. Further, there is: Where, , is the initial weight coefficient, , , , is the adjustment parameter, controlling the dynamic response intensity of the weight coefficient. When the temperature error is large, the system will increase the value, making the response of the control signal to the error more sensitive; when the temperature changes rapidly, increasing can enhance the adjustment of the error change rate and avoid over-response. 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: Where, ([[]]END]] , , ) is the external environmental disturbance, is the wind speed, is the humidity. According to the 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] Further, the safety control algorithm can perform protective shutdown or alarm in a timely manner in case of anomalies, preventing safety hazards such as overload, overvoltage, and overheating of air-conditioning equipment. 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 from working, 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 overpressure or low-pressure faults occur in the system, the system will automatically adjust the operating state of the compressor and even directly shut down the equipment in extreme cases, thus avoiding damage or safety accidents. Suppose the system state is represented by the state vector and the system state dynamic equation is expressed as: where, is the system state vector, is the actual humidity, is the change rate of the actual humidity, , , describe the state coupling relationship, the influence 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 constraint conditions: , is the safe range of the state, is the safe range of the control signal, and there are constraint conditions: where, is the temperature lower limit, is the temperature upper limit, is the humidity lower limit, is the humidity upper limit, is the power lower limit, is the power upper limit. To cope with the uncertainty of environmental disturbances ( , , ), the algorithm designs a robust controller to generate the control input in real time: , is the regularization factor. Considering the non-linear relationship between the control input and the state of the air-conditioning system, the robust controller uses non-linear optimization techniques to solve the problem of optimizing the state under the above-mentioned safety constraint conditions. The objective function is designed in the form of multi-objective weighting: where, , , are the objective weight coefficients used to balance the temperature, humidity, and power objectives. Through the Lagrange multiplier method, the objective function and constraints are integrated into the Lagrangian function: where, is the Lagrange operator, is the Lagrangian function, The vector of inequality functions used to describe the security constraints satisfies the KKT conditions as follows: .

[0017] Furthermore, the IO card module undertakes the control task in the safe mode when the main card fails. The FPGA chip on the IO card processes parameters such as temperature, humidity, pressure, and flow rate. In the normal working state, the IO card serves as the execution unit of the main card and executes the air-conditioning control tasks according to the instructions sent by the main card, including turning on and off the compressor, adjusting the frequency of the frequency converter, switching the state of the solenoid valve, and forwarding the control signal 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 thus automatically enter the safe mode. In the safe mode, the FPGA controls the output according to the preset truth table logic based on the current input signal. Since the logic control of the FPGA is hardware-based, the IO card can quickly respond to input changes in the safe mode, ensuring 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: redundant logic is provided inside the FPGA. When the input signal is abnormal or there is a short-term interference, the FPGA can automatically filter out the abnormal signal to avoid misoperation. In addition, the IO card has a fault detection function to monitor whether the actuator responds normally to the control instruction. If an abnormality is found, the FPGA will adopt corresponding safety strategies, including stopping the abnormal actuator or switching to the default safe 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 by wired means.

[0019] Furthermore, the safety logic control module ensures that the air-conditioning system can still maintain its basic functions in the safe mode, preventing the system from complete paralysis. The FPGA runs on the IO card. When the main card is working properly, the FPGA serves as the execution unit for signal processing, performs logical operations and signal transmission according to the instructions issued by the main card, ensuring that each actuator operates according to the predetermined logic. In the case of the failure of the main card, the safety logic control module must work independently. It first judges 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 the safe mode and take over the basic control tasks of the air-conditioning system. In the safe mode, the FPGA relies on the predefined truth table for logical control. Since the truth table is fixed, the control logic of the FPGA will not be interfered 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. By sensing environmental changes, it converts relevant information into electrical signals and then outputs 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 make appropriate responses according to environmental changes. The actuator module includes a compressor controller, a fan controller, a solenoid valve, a heater, and a frequency converter controller. After receiving signals from the control system, the actuator adjusts the working state of the equipment according to the instructions to achieve the environmental control effect.

[0022] Advantages of the present invention: The main card module collects the temperature, humidity, pressure, and flow parameters inside the carriage through sensors, and determines the operating mode of the air-conditioning system based on calculations and analyses, thereby optimizing the operating strategy of the air-conditioning equipment to ensure passenger comfort.

[0023] The safety logic control module ensures that the air-conditioning system can still maintain basic functions in the safe mode to prevent the system from completely paralyzing. When the main card is working properly, the FPGA serves as the execution unit for signal processing, responsible for logical operations and signal transmission to ensure that each actuator operates according to the predetermined logic. When the main card fails, the safety logic control module operates independently. It judges the working state of the main card by detecting the heartbeat signal of the main card. Once the main card is abnormal, the FPGA will take over the basic control tasks of the air-conditioning system and perform logical control relying on the predefined truth table. Since this control logic is not affected by the external environment, the system can still operate stably even under extreme conditions. To adapt to the complex electromagnetic environment of the subway train, the IO card has electrical isolation and anti-interference capabilities, and built-in redundant logic, which can effectively filter short-term interference in the input signal and avoid misoperations. In addition, the IO card also has a fault detection function, which can monitor whether the actuator responds normally to the control instructions. Once an abnormality is found, the FPGA will take corresponding safety measures, such as stopping the abnormal actuator or switching to the default safe state, to prevent system damage. Since public network connections are not allowed on the train, all inputs and outputs of the IO card are connected to the main card and external devices by wired means to ensure the security and reliability of data transmission.

[0024] The present invention also proposes a temperature control algorithm and a safety control algorithm. In safety control, the robust control theory is adopted, combining the uncertainty of environmental disturbances and the multivariable characteristics of the system, and a robust optimization problem is designed. By solving the robust optimization problem, the controller can adjust the control input in real time when facing complex external disturbances, ensuring that the system can maintain safe and stable operation in all situations. This algorithm innovatively applies the Lyapunov stability theory to the safety control of the air-conditioning system. By constructing an appropriate Lyapunov function, it analyzes and ensures that the system can maintain a stable state when facing external disturbances. Description of the Drawings

[0025] The invention is further described with reference to the accompanying drawings. However, the embodiments in the drawings do not constitute any limitation to the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to the following drawings without creative efforts.

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

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments 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. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0028] Please refer to Figure 1 , and the present invention will be further described in combination with the following examples.

[0029] Refer to Figure 1 , the present invention aims to provide an air-conditioning control system for 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 carriage through sensors, determines the operating mode of the air-conditioning system based on calculations and analyses, adjusts the operating strategy of the air-conditioning equipment, and ensures passenger comfort; the IO card module undertakes the control task in the safety mode when the main card fails, can quickly respond to input changes, and 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 and prevents the system from complete paralysis; the sensor module senses environmental changes, 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.

[0030] Specifically, the main card module collects the temperature, humidity, pressure, and flow rate parameters inside the carriage through sensors, determines the operating mode of the air conditioning system based on calculations and analyses, 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 and improve 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.

[0031] The operating modes include reducing power consumption in emergency situations or enhancing the cooling capacity in high passenger load conditions.

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

[0033] Specifically, 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 as , the actual indoor temperature is , the external environmental temperature is , and the control objective of the air conditioning system is to adjust the cooling and heating capacity of the air conditioning according to the temperature difference between and : , where is the air mass flow rate, is the specific heat capacity of the air, is the cooling power of the air conditioning system, is the heating power of the air conditioning system, is the environmental heat load, is the actual indoor temperature change rate. To achieve precise temperature regulation, the air conditioning system performs feedback control by monitoring the error between the indoor temperature and the set temperature . The temperature error is defined as : The temperature error will directly affect the control strategy of the air conditioning. Within different error ranges, the cooling or heating capacity of the air conditioning will be dynamically adjusted. To achieve smooth transition and avoid over-regulation, the adjustment of the error adopts a dynamic weighting mechanism: Where: is the control signal, , are the dynamic weighting coefficients, indicating the influence of the temperature error and the error change rate on the control signal, is the change rate. Further, there is: Among them, , is the initial weight coefficient, , , , is the adjustment parameter, which controls the dynamic response intensity of the weight coefficient. When the temperature error is large, the system will increase the value, making the response of the control signal to the error more sensitive; when the temperature changes rapidly, increasing can enhance the adjustment of the error change rate and avoid over-response. To ensure the stability of the temperature control system, the stability conditions of the system are introduced. The temperature dynamic equation of the system is: Among them, ( , , ) is the external environmental disturbance, is the wind speed, is the humidity. According to the 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 a timely manner in case of anomalies, preventing safety hazards such as overload, overvoltage, and overheating of air-conditioning equipment. 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 from working, 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 overpressure or low-pressure faults, the system will automatically adjust the operating state of the compressor, and even directly shut down the equipment in extreme cases, thus avoiding damage or safety accidents. Assuming that the system state is represented by the state vector , the system state dynamic equation is expressed as: Among them, is the system state vector, is the actual humidity, is the change rate of the actual humidity, , , describe the state coupling relationship, the influence of the 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 constraint conditions: , is the safety range of the state, is the safety range of the control signal, and there are constraint conditions: Among them, is the temperature lower limit, is the temperature upper limit, is the lower humidity limit, is the upper humidity limit, is the lower power limit, is the upper power limit. To cope with the uncertainty of environmental disturbances ( , , ), the algorithm designs a robust controller to generate control inputs in real time : , is the regularization factor. Considering the non-linear relationship between the control input and the state of the air-conditioning system, the robust controller uses non-linear optimization techniques to solve the problem of optimizing the state under the above-mentioned safety constraints. The objective function is designed in the form of multi-objective weighting: where, , , are the objective weight coefficients, used to balance the temperature, humidity and power objectives. Through the Lagrange multiplier method, the objective function and the constraints are integrated into the Lagrangian function: where, is the Lagrange operator, is the Lagrangian function, is the vector of inequality functions used to describe the safety constraints, and satisfies the KKT conditions as follows: .

[0035] Specifically, the IO card module undertakes the control task in the safety mode when the main card fails. The FPGA chip on the IO card processes temperature, humidity, pressure and flow parameters. When the IO card is in the normal working state, it acts as an execution unit of the main card and executes the air-conditioning control tasks according to the instructions sent by the main card, including turning on and off the compressor, adjusting the frequency of the frequency converter, switching the state of the solenoid valve, and forwarding the control signal 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 thus automatically enters the safety mode.

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

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

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

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

[0041] Specifically, the safety strategies include: 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 by wired means.

[0042] Specifically, the safety logic control module ensures that the air-conditioning system can still maintain basic functions in the safe mode to prevent the system from complete paralysis. The FPGA runs on the IO card. When the main card is working properly, the FPGA serves 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 case of the main card failure, the safety logic control module must work independently.

[0043] Specifically, the safety logic control module first determines whether the main card is running 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 the safe mode and take over the basic control tasks of the air-conditioning system.

[0044] Specifically, in the safe mode, the FPGA relies on a predefined truth table for logical control. Since the truth table is fixed, the control logic of the FPGA will not be interfered 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 according to the current input signal, such as the data of the temperature sensor, and adjust the output frequency of the frequency converter according to the set logic to control the rotation speed of the fan, so as to realize the basic regulation of the temperature in the carriage.

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

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

[0048] Specifically, the sensor module includes a temperature sensor, a humidity sensor, a pressure sensor, and a flow sensor. By sensing environmental changes, 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 make appropriate responses according to environmental changes. The actuator module includes a compressor controller, a fan controller, a solenoid valve, a heater, and a frequency converter controller. After receiving signals from the control system, the actuator adjusts 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 refrigeration and heating. The on / off of the compressor controller directly affects the refrigeration and heating efficiency of the air-conditioning system.

[0051] Specifically, the fan controller adjusts the speed, start / stop of the fan. By controlling the fan speed, the intensity of 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. The system can accurately regulate the flow of refrigerant in different working modes to achieve the best refrigeration or heating effect.

[0053] Specifically, the frequency converter controller realizes the flexible adjustment of the compressor by changing the working frequency of the compressor, thereby controlling the refrigeration or heating effect of the air-conditioning system and avoiding energy waste and equipment wear caused by frequent start / stop of the compressor.

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

[0055] 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 complete paralysis. When the main card is working properly, the FPGA serves as the execution unit for signal processing, responsible for logic operations and signal transmission to ensure that each actuator operates according to the predetermined logic. When the main card fails, the safety logic control module operates independently. It judges the working state of the main card by detecting the heartbeat signal of the main card. Once the main card is abnormal, the FPGA will take over the basic control tasks of the air conditioning system and perform logic control relying on the predefined truth table. Since this control logic is not affected by the external environment, the system can still operate stably even under extreme conditions. To adapt to the complex electromagnetic environment of the subway train, the IO card has electrical isolation and anti-interference capabilities and built-in redundant logic, which can effectively filter short-term interference in the input signal to avoid misoperation. In addition, the IO card also has a fault detection function, which can monitor whether the actuator responds to the control instruction normally. Once an abnormality is found, the FPGA will adopt corresponding safety strategies, such as stopping the abnormal actuator or switching to the default safety state, to prevent system damage. Since public network connections are not allowed on the train, all inputs and outputs of the IO card are connected to the main card and external devices by wired means to ensure the security and reliability of data transmission.

[0056] The present invention also proposes a temperature control algorithm and a safety control algorithm. The robust control theory is adopted in the safety control, combined with the uncertainty of environmental disturbances and the multivariable characteristics of the system, and a robust optimization problem is designed. By solving the robust optimization problem, the controller can adjust the control input in real time when facing complex external disturbances to ensure that the system can maintain safe and stable operation in all cases. This algorithm innovatively applies the Lyapunov stability theory to the safety control of the air conditioning system. By constructing an appropriate Lyapunov function, it analyzes and ensures that the system can maintain a stable state when facing external disturbances.

[0057] Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent substitution on some of the technical features. Any modification, equivalent substitution, and improvement made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An air-conditioning control system with safety control based on FPGA, comprising 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 operation mode of the air-conditioning system based on calculation and analysis, and adjusts the operation 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 converts the relevant information into electrical signals by sensing changes in the environment, 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.

2. According to claim 1, an air conditioning control system with safety control based on FPGA, characterized in that: 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 operation status of the train to ensure passenger comfort while improving energy efficiency. The main card module communicates with the train control 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.

3. According to claim 2, an air conditioning control system with safety control based on FPGA, characterized in that: The main card module formulates the control strategy of the air conditioning system and implements the control decision, including temperature control algorithm and 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 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. To achieve accurate temperature regulation, the air conditioning system monitors the indoor temperature and set temperature The error between the two is used for feedback control. The temperature error is defined as : Temperature error It will directly affect the control strategy of the air conditioner. Within different error ranges, the cooling or heating capacity of the air conditioner will be dynamically adjusted. In order to smooth the 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. 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 the 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.

4. The air conditioning control system based on FPGA for safety control according to claim 3, characterized in that: 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. 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 state 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 It 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 influence of control input on the state, and the propagation of external disturbances respectively. To ensure the safety of the system, 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, is 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 the 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: .

5. The air conditioning control system with safety control based on FPGA according to claim 1, characterized in that: The IO card module assumes the control task in the safe mode when the main card fails. The FPGA chip on the IO card processes temperature, humidity, pressure, and flow parameters. The IO card acts as the execution unit of the main card under normal working conditions 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 state. 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 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 logic control of the FPGA is based on hardware implementation, the IO card can respond quickly to input changes in the safe mode to ensure the stability of the system.

6. The air conditioning control system based on FPGA for safety control according to claim 5, characterized in that: 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. 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 responds to the control command normally. If an abnormality is found, the FPGA will adopt corresponding 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 methods.

7. 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 working normally, the FPGA, as the execution unit of signal processing, 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 affected by the external environment and can maintain stable operation even under extreme conditions.

8. 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. It 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.

9. 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 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.

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