Aircraft electric heating control system and fault monitoring method based on BITE health management

Abstract

The application belongs to the field of water / sewage system electromechanical equipment of civil aviation, and relates to an aircraft electric heating control system and a fault monitoring method based on BITE health management. The system comprises a plurality of independent electric heating control valves arranged on the water / sewage system. Any electric heating control valve comprises an electric mechanism, a valve body and a heating assembly. The electric mechanism is used to drive the valve body to rotate to control the flow of the passage. The valve body is arranged in the passage, and the periphery of the valve body is provided with the heating assembly according to the requirement, which is used to control the temperature of the valve body. The electric mechanism is further integrated with a controller, the controller is integrated with a fault monitoring module, and the controller is in real-time communication with an upper computer, which is used to realize the control of the electric mechanism, the temperature control of the heating assembly and the fault monitoring. The application integrates the functions of valve opening and closing control, position feedback, electric heating, overheating protection and health management, has high component integration degree, reduces the control complexity of the upper system controller and improves the reliability of the system.

Description

Technical Field

[0001] This invention belongs to the field of electromechanical equipment for civil aviation water / sewage systems, and relates to an aircraft electric heating control valve based on BITE health management. Background Technology

[0002] The water / wastewater system includes a water subsystem, a wastewater treatment subsystem, and a laundry wastewater subsystem. The electromechanical control valves involved mainly include filler / drain valves (water system), front / rear laundry wastewater discharge valves (wastewater treatment system), and front / rear in-flight drain valves (laundry wastewater system). These three types of electromechanical valves have similar functional structures, with the front / rear in-flight drain valve being a typical example. The function of the front / rear in-flight drain valve is to automatically lock the remaining water discharge function when the aircraft's daily operation ends by pressing the drain button located on the control panel at the top of the cockpit. The drain button transmits discrete signals to the system controller, which controls the opening and closing of the in-flight drain valve. The external drain boom should be equipped with a temperature sensor; when the temperature sensor on the external drain boom measures a temperature below 5°C, it should automatically lock the remaining water discharge function. Based on the operating scenario and safety and reliability requirements, the front / rear in-flight drain valve is required to have functions such as electric heating, overheat protection, valve opening / closing, opening / closing position feedback, and health management (BITE activation, periodic IFBIT, and fault reporting). Traditional control valves, which are heated through pipelines, do not have fault identification and reporting functions. This invention, an aircraft electric heating control valve based on BITE health management, adds electric heating, overheat protection, and health management functions, and has higher requirements for integration, complexity, and reliability. Summary of the Invention

[0003] The purpose of this invention is:

[0004] This invention provides a modular, highly integrated, and highly reliable water / sewage system control valve with functions such as electric heating, overheat protection, valve opening / closing, opening / closing position feedback, and health management (start-up BITE, periodic BITE, and fault reporting), which solves the problem of valve icing under freezing test and low-temperature operating conditions.

[0005] To solve this technical problem, the technical solution of the present invention is as follows:

[0006] This invention proposes an aircraft electric heating control system based on BITE health management, comprising several independent electric heating control valves installed on a water / sewage system. Each electric heating control valve includes an electric mechanism, a valve body, and a heating component. The electric mechanism drives the valve body to rotate to control the flow rate of the channel. The valve body is placed inside the channel, and a heating component is installed around the valve body as needed to control the temperature of the valve body. The electric mechanism also integrates a controller, which integrates a fault monitoring module. The controller communicates with a host computer in real time to realize the control of the electric mechanism, the temperature control of the heating component, and fault monitoring.

[0007] Furthermore, the heating component employs a highly reliable temperature protection design;

[0008] The electric heating design features triple thermal protection to prevent icing and blockage caused by low temperatures and overheating caused by overheating.

[0009] First layer of thermal protection:

[0010] The heating pad should be equipped with a temperature sensor, which transmits the sensed temperature signal to the system controller through a socket. The system controller controls the heating of the heating pad. Heating is started when the temperature is below 5℃±5℃, and the heating circuit is cut off and heating is stopped when the temperature reaches the preset value of 20℃±5℃.

[0011] Second layer of thermal protection:

[0012] When the temperature sensor fails, the temperature relay will disconnect when the temperature reaches 50±5℃; and will close when the temperature drops to 35±5℃.

[0013] Third layer of thermal protection:

[0014] When the temperature relay fails, the fuse blows and the circuit is broken when the temperature reaches 95±5℃.

[0015] Furthermore, the electric mechanism includes a motor, a reduction mechanism, and a motor controller, which can realize motor drive, switch feedback, BITE fault monitoring, and CAN data communication functions.

[0016] Furthermore, the valve body includes a valve housing, a shaft, and a valve core, which can realize mechanical switching and sealing functions. The valve core is disposed inside the housing and deflects under the drive of the shaft to control the flow rate in the channel.

[0017] Furthermore, the heating assembly includes a heating wire, a circuit board, and a heat insulation cover assembly. The heating wire is arranged inside the heat insulation cover assembly. The heating wire is controlled by the circuit board, and the controller enables electric heating, thermal protection, and thermal isolation functions.

[0018] Furthermore, the heating assembly consists of an upper heating pad assembly, a lower heating pad assembly, a protective cap, an insulation sleeve, a heating wire, a temperature relay, a thermal protector, a temperature sensor, and an electrical connector. The upper and lower heating pad assemblies are the main functional components of the heating pad, consisting of an internal heating wire and an external rubber layer, enabling effective heat transfer and protecting the internal heating wire. The temperature relay, thermal protector, and temperature sensor ensure the sensing and control of temperature, and the electrical connector connects to the power supply. All components of the heating pad work together to achieve low-temperature heating, overheat protection, and thermal insulation.

[0019] In another aspect, this invention also proposes a fault monitoring method for the aforementioned aircraft electric heating control valve. Several independent electric heating control valves installed on the water / sewage system operate independently under the control of a host computer and their own controllers. The health status of the control valves is detected according to different fault modes. These fault modes are categorized based on the structural characteristics of the control valves as digital communication faults, power input faults, CAN communication faults, motor faults, valve actuation faults, and host computer connection faults. During the operation of the control valves, each functional component communicates with the controller in real time via CAN communication and hardwired connections.

[0020] Digital communication fault monitoring:

[0021] The controller determines whether digital communication is normal by testing whether the instructions can be executed correctly. If more than three arithmetic and logical operations are performed and the result is inconsistent with the expected result more than three times, it is determined to be a digital communication failure.

[0022] Power input fault detection:

[0023] The controller samples the power supply voltage once in each sampling cycle. If the sampled power supply voltage value is within the threshold range, the power supply is considered normal. If the sampled power supply voltage is outside the threshold range for multiple consecutive sampling cycles, the power supply input is considered faulty.

[0024] CAN communication fault detection:

[0025] If the CAN communication between the controller inside the control valve and the host computer is interrupted for more than the set threshold time, the CAN communication is determined to be faulty. If the communication is restored, the software will resume normal operation.

[0026] Motor fault detection:

[0027] The monitoring module inside the controller collects the motor's HALL signal A, HALL signal B, and HALL signal C once per sampling cycle, and performs five consecutive tests. If more than three of the collected signals output all 0 or all 1, the motor's HALL is determined to be faulty.

[0028] Valve actuation fault detection:

[0029] The controller checks the status of the photoelectric switch once per sampling cycle. If the extended and retracted state is detected to be effective for a certain period of time, the photoelectric switch is determined to be faulty.

[0030] Host computer connection fault monitoring:

[0031] The system uses four I / O interfaces to determine the identity ID and connection status of the control valve. A protocol table for high and low potential combinations of the four I / O interfaces is established to assign an identity ID to each control valve. Each time the device is connected and powered on, the control valve determines its installation location and valve identity through the data combination of the four I / O interfaces connected to the host computer. When the control valve is connected normally, the host computer will receive the control valve's identity information. When the control valve connection fails, the control valve's identity information will be lost, and the corresponding control valve fault will be indicated.

[0032] Furthermore, the controller comprises a control module and a drive control circuit, a power conversion circuit, a power drive circuit, a position feedback signal acquisition circuit, a control circuit, and a power drive circuit.

[0033] The drive control circuit includes a power secondary conversion circuit, a motor rotation direction determination circuit, a position feedback signal acquisition circuit, an extreme position determination circuit, an extreme position indication circuit, a motor control circuit, and a power control circuit.

[0034] The power conversion circuit performs secondary power conversion on the aircraft's 28V power supply, converting it to +15V power to provide power to the control circuit, drive circuit, limit switches, and Hall sensors in the actuator.

[0035] The power drive circuit adopts a three-phase bridge inverter drive circuit to complete the functions of driving power components and power inversion, and drive the permanent magnet brushless DC motor on the corresponding channel to work.

[0036] In the position feedback signal acquisition circuit, the position feedback of the actuator adopts a photoelectric switch assembly, which is installed on the output shaft of the actuator to detect the position of the output shaft of the actuator in real time;

[0037] The limit position discrimination and indication circuit compares the collected position feedback signal with a comparator. When the position feedback signal voltage is greater than a certain value, it determines that the mechanism has reached the closed limit position and reports the closed limit position signal to the host computer. When the position feedback signal voltage is less than a certain value, it determines that the mechanism has reached the open limit position and reports the open limit position signal to the host computer.

[0038] The main function of the control circuit is to collect forward and reverse commands sent by the host computer, position indication signals and Hall signals fed back by the actuator, and output control commands for the permanent magnet brushless DC motor and open or close limit position signals after performing logical combination judgments.

[0039] The power drive circuit adopts a three-phase bridge inverter drive circuit to complete the functions of driving power components and power inversion, and drive the permanent magnet brushless DC motor on the corresponding channel to work.

[0040] Furthermore, each control valve installed on the water / sewage system has a consistent electrical design, and error prevention is implemented through the control valve mechanical interface to ensure that the identity ID of each control valve corresponds one-to-one with its corresponding setting location when the host computer connects to the fault monitoring system.

[0041] Technical effects of the present invention:

[0042] The present invention provides an aircraft electric heating control valve based on BITE health management, which has four main advantages:

[0043] 1) This invention integrates valve switching control, position feedback, electric heating, overheat protection, and health management functions into one unit. The high degree of component integration reduces the control complexity of the upper system controller and improves the reliability of the system.

[0044] 2) This invention is equipped with an electric heating and overheat protection module, which solves the problems of low-temperature operation and freezing test of valves, as well as short circuit and fire caused by overheating;

[0045] 3) This invention features BITE health detection. Through PBIT, IFBIT, and fault reporting, it can dynamically monitor the health status of an aircraft electric heating control valve based on BITE health management and report the cause of the fault to the aircraft host computer to achieve fault isolation. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0047] Figure 2 , Figure 3 This is a schematic diagram of the structure of the present invention;

[0048] Figure 4 This is a schematic diagram of the heating pad structure of the present invention;

[0049] Figure 5 This is a schematic diagram of the electrical interface principle of the present invention;

[0050] Figure 6 This is a block diagram of the fault monitoring architecture of the present invention;

[0051] Figure 7 This is a schematic diagram of the filtering function of the present invention. Detailed Implementation

[0052] The present invention will now be described in further detail with reference to the accompanying drawings. See also: Figure 1The present invention specifically designs an aircraft electric heating control valve based on BITE health management, which includes a ball valve 1, a gasket 2, an adjusting gasket 3, a butterfly spring 4, a pipe joint I 5, a sealing ring I 6, a housing 7, a mounting base assembly 8, a hole elastic retaining ring 9, a retaining ring 10, a sealing ring II 11, a wear-resistant gasket 12, a rotating shaft 13, a sealing ring III 14, a valve seat 15, a pipe joint II 16, a screw 17, a washer 18, an electric mechanism 19, a hexagonal screw 20, a cross screw 21, a sealing ring IV 22, a plug 23, a heating pad 24, and a plug 25.

[0053] The housing 7 is connected to pipe joint I5 and pipe joint II16 by screws 17 and washers 18. The mounting base assembly 8 is connected to the housing 7 and the electric mechanism 19 by washers 18, hexagonal screws 20 and Phillips screws 21. The plug caps 23 and 25 are mainly used for interface protection.

[0054] The retaining rings 9 and 10 are used to pre-tighten the shaft 13 and the housing 7; the wear-resistant gasket 12 is installed between the shaft 13 and the housing 7 to provide transition friction; the sealing rings I6, II11, III14, and IV22 are sealing elements to achieve assembly sealing of the connecting parts. Pipe fittings I5 and II16 provide installation positions for other components, used to connect system pipelines and products, and to connect or close system pipelines.

[0055] Adjusting shims 3 and butterfly springs 4 achieve pre-tightening of the ball valve 1 and valve seat 15, thus achieving a sealing function. The housing 7, valve seat 15, pipe joint I 5, and pipe joint II 16 together fix the ball valve 1, achieving a sealing function and preventing external leakage; the rotating shaft 13 outputs power from the electric mechanism to the ball valve 1; the electric mechanism 19 enables the product to achieve the fully open and fully closed functions of the valve. The heating pad 24 is mainly composed of components such as an upper heating pad assembly 26, a lower heating pad assembly 27, a protective cap 28, an insulation sleeve 29, a heating wire 30, a temperature relay 31, a thermal protector 32, a temperature sensor 33, and an electrical connector 34. The upper heating pad assembly 26 and the lower heating pad assembly 27 are the main functional components of the heating pad 24, consisting of an internal heating wire 30 and an external rubber, which realizes effective heat transfer and protects the internal heating wire. The temperature relay 31, the thermal protector 32, and the temperature sensor 33 ensure the realization of temperature sensing and control functions, and the electrical connector 34 connects to the power supply. All components of the heating pad 24 work together to achieve low-temperature heating, overheat protection, heat insulation, and prevent freezing, jamming, and overheating short circuits.

[0056] The working principle of this invention is:

[0057] A ball valve-type aircraft electric heating control valve based on BITE health management is provided. The ball valve 1 is integrated into a housing 7 and is opened and closed by an electric mechanism 19. A handle is also provided for opening / closing the valve. The housing 7 is covered with a heating pad 24. When the temperature is too low, the heating pad 24 receives a signal from the system controller and activates the electric heating function. The electric heating pad 24 is equipped with a three-level temperature protection function. The system controller cuts off the power supply upon receiving an overheat signal from the temperature sensor 33, or the electric heating control valve achieves overheat protection through a temperature relay 31 and a thermal protector 32. The heating pad 24 is covered with a PVDF insulation cover to reduce heat loss from the electric heating control valve. During the start-up or operation of the electric heating control valve, if a fault signal from the valve body is detected, the controller can report a 28V signal (+16V to +32V) to the host computer via CAN data communication or hardwired connection to reflect the product fault.

[0058] In the specific implementation process, the fault monitoring method for the aircraft electric heating control system based on BITE health management includes the following monitoring contents:

[0059] A BITE-based aircraft electric heating control valve can detect the valve's health status according to the cause of the fault. Fault modes can be mainly categorized into DSP faults (digital communication faults), power input faults, CAN communication faults, motor faults, valve actuation faults, and host computer connection faults. Fault detection methods include BITE health checks, specifically PBIT (Internal Motor Test) and IFBIT (Internal Flight Test). Monitoring signal transmission utilizes both CAN communication and hard-wired connections, ensuring ample communication margin.

[0060] DSP fault detection:

[0061] The software determines whether the DSP is working properly by testing whether the instructions can be executed correctly. If the arithmetic and logical operations are executed more than 3 times and the result is inconsistent with the expected result more than 3 times, the DSP is judged to be faulty.

[0062] Power input (voltage) fault detection:

[0063] The software collects the 28V power supply voltage every 10ms. If the collected 28V power supply voltage value is within the threshold range (13V-32V), the 28V power supply is considered normal. If the collected 28V power supply voltage is outside the threshold range for 50 consecutive ms, the 28V power supply detection is considered faulty.

[0064] CAN communication fault detection:

[0065] If the CAN communication with the host computer is interrupted for more than 500±10ms, the CAN communication is considered to be faulty. If the communication is restored, the software will resume normal operation.

[0066] Hall fault detection:

[0067] The software collects the motor's HALL signal A, HALL signal B, and HALL signal C every 20ms, performing 5 checks. If more than 3 of the collected signals output all 0 or all 1, the motor's HALL is determined to be faulty.

[0068] Valve actuation fault detection (photoelectric switch status detection):

[0069] The software checks the status of the photoelectric switch every 10ms. If the extended and retracted state is detected to be effective for 100ms, the photoelectric switch is determined to be faulty.

[0070] Host computer connection (control valve connection fault status detection):

[0071] The control valve's identity ID and connection status are determined using four I / O ports: CPIOC8, CPIOC9, CPIOC10, and CPIOC11. Specifically, a high / low voltage combination protocol for these four I / O ports is defined to establish the identity ID for each control valve. Each time the device is connected and powered on, the control valve determines its installation location and valve identity by combining data from the four I / O ports connected to the host computer (each control valve has a consistent electrical design; error prevention is primarily achieved through the control valve's mechanical interface).

[0072] When the control valve is connected normally, the host computer will receive the control valve's identification information; when the control valve is connected incorrectly, the control valve's identification information will be lost (generally, the IO port information is 0000 or 1111).

[0073] Example 1: Taking a certain type of control valve assembly as an example, the specific connection judgment is as follows: When the four IO ports CPIOC8, CPIOC9, CPIOC10, and CPIOC11 send data 0111 to the host computer, it indicates that the connection is normal and the connected device is the front air drain valve. When the product is working, when the four IO ports CPIOC8, CPIOC9, CPIOC10, and CPIOC11 send data 0000 or 1111, it indicates that the product has a connection failure. Similarly, when the four IO ports CPIOC8, CPIOC9, CPIOC10, and CPIOC11 send data 1011 to the host computer, it indicates that the connection is normal and the connected device is the rear air drain valve. When the product is working, when the four IO ports CPIOC8, CPIOC9, CPIOC10, and CPIOC11 send data 0000 or 1111, it indicates that the product has a connection failure.

[0074]

[0075]

[0076] In the design of the heating components, both electric heating and thermal protection adopt a modular design.

[0077] 1) Structural design of electric heating and thermal protection module:

[0078] This invention relates to an electric heating and thermal protection module comprising a PT100 temperature sensor, a heating pad, a temperature relay, a thermal protector, and an insulation sleeve. The heating pad mainly consists of an upper heating pad assembly, a lower heating pad assembly, a protective cap, an insulation sleeve, heating wires, a temperature relay, a thermal protector, an electrical connector, and a grounding wire. The upper and lower heating pad assemblies are the main functional components of the heating pad, consisting of internal heating wires and external rubber, ensuring effective heat transfer and protecting the internal heating wires.

[0079] The heating wire generates heat to achieve the heating function; the heating wire is vulcanized in the middle of the rubber; the temperature relay and thermal protector ensure the function of temperature sensing and control; the wires and electrical connectors connect to the power supply; the insulation sleeve reduces heat loss to the surrounding environment, allowing the internal water to remain above 0°C for a longer period of time, avoiding frequent electric heating and reducing power consumption. The insulation sleeve is cut and sewn into the required shape and wrapped around the outer layer of rubber; Velcro fasteners secure the heating pad to the valve.

[0080] 2) High-reliability temperature protection design:

[0081] The electric heating and temperature control thermal protection system is rated DAL B. Since the electric heating element itself is a consumable component, it is designed with triple thermal protection to prevent icing and blockage caused by low temperatures and overheating caused by overheating.

[0082] First layer of thermal protection:

[0083] A temperature sensor should be installed inside the heating pad. The sensed temperature signal is transmitted to the system controller through the socket. The system controller controls the heating of the heating pad. Heating is started when the temperature is below 5℃±5℃, and the heating circuit is cut off and heating is stopped when the temperature reaches the preset value of 20℃±5℃.

[0084] Second layer of thermal protection:

[0085] When the temperature sensor fails, the temperature relay will disconnect when the temperature reaches 50±5℃; and will close when the temperature drops to 35±5℃.

[0086] Third layer of thermal protection:

[0087] When the temperature relay fails, the fuse blows and the circuit is broken when the temperature reaches 95±5℃.

[0088] 3) High temperature resistant and fireproof design:

[0089] To reduce heat dissipation between the heating pad and the environment, and to avoid fire resistance and insulation failures caused by prolonged high-temperature operation, non-metallic materials are selected that meet combustion performance requirements. The main material, silicone rubber, incorporates flame-retardant materials, making it flame-retardant, non-toxic, and pollution-free. The insulation sleeve uses materials with good insulation and chemical stability, meeting fire resistance requirements. The conductors are AF250 high-temperature resistant conductors, with an operating temperature range of -65℃ to 200℃, and are flame-retardant and non-toxic. To prevent high temperatures, the heating wires are evenly distributed inside the heating pad, and their distribution is inspected using an X-ray machine to avoid localized high temperatures caused by uneven distribution. For excellent heat transfer, the heating pad's shape matches the air drain valve's shape, and the two are tightly fitted together using Velcro. After installation, this ensures that heat is quickly and evenly transferred to the air drain valve surface, preventing the heating pad from overheating.

[0090] 4) Insulation and dielectric design:

[0091] When a 500VDC voltage is applied between the heating circuit and the rubber, the insulation resistance should not be less than 20MΩ; when a 50VDC voltage is applied between the temperature sensor and the rubber, the insulation resistance should not be less than 10MΩ. When a 1500VAC RMS voltage is applied between the heating circuit and the rubber, the leakage current should not exceed 2mA. The following measures should be taken:

[0092] a) After wrapping the heating wire with insulating fiber cloth, the heating wire is sealed in rubber by vulcanization, so that the heating wire is not exposed and is isolated from the outside world;

[0093] b) When performing X-ray inspection, the heating wire should be evenly distributed in the middle of the rubber;

[0094] c) The junction of the heating wire should be smooth, free of burrs and protrusions;

[0095] d) The heating wire is arranged in a large arc without any sharp points in the middle of the rubber;

[0096] e) The temperature relay and temperature sensor are sealed in the groove of the heating pad assembly, isolated from the outside world;

[0097] f) Rubber itself has good insulation properties, with a volume resistivity of 10¹⁶~10¹⁸ Ω·cm and a withstand voltage of 18kV.

[0098] Secondary design features of this invention: Complex hardware and software design based on DO178 and DO254:

[0099] 1) Controller circuit design

[0100] The controller consists of control software and drive control circuit, power conversion circuit, power drive circuit, position feedback signal acquisition circuit, control circuit, and power drive circuit.

[0101] The drive control circuit includes a power secondary conversion circuit, a motor rotation direction determination circuit, a position feedback signal acquisition circuit, an extreme position determination circuit, an extreme position indication circuit, a motor control circuit, and a power control circuit.

[0102] The main function of the power conversion circuit is to perform secondary power conversion on the aircraft's 28V power supply, converting it to +15V power to provide power for the control circuit, drive circuit, limit switches, and Hall sensors in the actuator.

[0103] The power drive circuit adopts a three-phase bridge inverter drive circuit to complete the functions of driving power components and power inversion, and drive the permanent magnet brushless DC motor on the corresponding channel to work.

[0104] In the position feedback signal acquisition circuit, the position feedback of the actuator adopts a photoelectric switch assembly, which is installed on the output shaft of the actuator to detect the position of the output shaft of the actuator in real time.

[0105] The limit position discrimination and indication circuit compares the collected position feedback signal with a comparator. When the position feedback signal voltage is greater than a certain value, it determines that the mechanism has reached the closed limit position and reports the closed limit position signal (ground / open signal) to the host computer. When the position feedback signal voltage is less than a certain value, it determines that the mechanism has reached the open limit position and reports the open limit position signal (ground / open signal) to the host computer.

[0106] The main function of the control circuit is to collect the forward and reverse commands sent by the host computer, the position indication signals and Hall signals fed back by the actuator, and after performing logical combination judgment, output the control commands of the permanent magnet brushless DC motor and the open (or close) limit position signals.

[0107] The power drive circuit adopts a three-phase bridge inverter drive circuit to complete the functions of driving power components and power inversion, and drive the permanent magnet brushless DC motor on the corresponding channel to work.

[0108] 2) Lightning protection design:

[0109] In lightning induced transient sensitivity testing, pin-injection testing carries greater energy than cable testing. Furthermore, pin-injection testing considers the direct protection design of the product circuitry, while cable testing considers the overall product design. Therefore, circuit design should focus on energy protection design for pin-injection testing of interface circuits. A differential-mode protection circuit is used. Under normal conditions, the transient suppression diode is in the off state, with leakage current only a few microamps, and the lightning protection branch is not conductive. When an induced lightning overvoltage occurs, the voltage across the transient suppression diode rises and breaks down, rapidly becoming a low-resistance state, absorbing surge energy and clamping the voltage to a lower level. For voltages exceeding the device's withstand voltage, the subsequent surge suppressor absorbs the energy.

[0110] 3) Lightning protection, filtering, and surge protection module design:

[0111] The filtering component consists of three circuits (modules) with different functions: lightning protection (absorbing peak voltage) circuit, power supply filtering module, and surge module.

[0112] Its workflow is as follows: After the 28V DC power supply line and signal line pass through the electrical connector, spike voltage suppression (lightning protection) is first applied to the power supply line and signal line to protect the subsequent circuit from breakdown damage, meeting the relevant requirements of power supply compatibility and lightning induction sensitivity A3J3L3 in RTCA / DO-160G; then, the power supply line and signal line are filtered to ensure that interference generated by the electric mechanism does not enter the power supply line and signal line through conducted coupling, meeting the relevant requirements of electromagnetic compatibility in RTCA / DO-160G; finally, surge protection is applied to the 28V DC power supply line to suppress surge voltages and clamp them below the breakdown voltage value of the subsequent circuit, thereby protecting the circuit. Simultaneously, the surge module includes reverse voltage protection to prevent damage to the subsequent circuit when the positive and negative polarities of the power supply line are reversed.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. An aircraft electric heating control system based on BITE health management, characterized in that, The system includes several independent electrically heated control valves installed on a water / sewage system. Each electrically heated control valve includes an electric mechanism, a valve body, and a heating component. The electric mechanism drives the valve body to rotate to control the flow rate of the channel. The valve body is placed inside the channel, and a heating component is installed around the valve body as needed to control the temperature of the valve body. The electric mechanism also integrates a controller, which integrates a fault monitoring module. The controller communicates with a host computer in real time to realize the control of the electric mechanism, the temperature control of the heating component, and fault monitoring. The heating component adopts a high-reliability temperature protection design. The electric heating design features triple thermal protection to prevent freezing and blockage caused by low temperatures and overheating caused by overheating. First layer of thermal protection: The heating pad should be equipped with a temperature sensor, which transmits the sensed temperature signal to the system controller through a socket. The system controller controls the heating of the heating pad. Heating is started when the temperature is below 5℃±5℃, and the heating circuit is cut off and heating is stopped when the temperature reaches the preset value of 20℃±5℃. Second layer of thermal protection: When the temperature sensor fails, the temperature relay will disconnect when the temperature reaches 50±5℃; and will close when the temperature drops to 35±5℃. Third layer of thermal protection: When the temperature relay fails, the fuse blows and the circuit is broken when the temperature reaches 95±5℃. The heating assembly includes a heating wire, a circuit board, and a heat insulation cover assembly. The heating wire is arranged inside the heat insulation cover assembly. The heating wire is controlled by the circuit board, and the controller realizes the functions of electric heating, thermal protection, and thermal isolation. The heating assembly consists of an upper heating pad assembly, a lower heating pad assembly, a protective cap, a heat insulation sleeve, a heating wire, a temperature relay, a thermal protector, a temperature sensor, and an electrical connector assembly. The upper and lower heating pad assemblies are the main functional components of the heating pad, consisting of an internal heating wire and an external rubber, realizing effective heat transfer and protecting the internal heating wire. The temperature relay, thermal protector, and temperature sensor ensure the realization of temperature sensing and control functions, and the electrical connector is connected to the power supply. All components of the heating pad work together to achieve low-temperature heating, overheat protection, and heat insulation.

2. The aircraft electric heating control system based on BITE health management as described in claim 1, characterized in that, The electric mechanism includes a motor, a reduction mechanism, and a motor controller, which can realize motor drive, switch feedback, BITE fault monitoring, and CAN data communication functions.

3. The aircraft electric heating control system based on BITE health management as described in claim 1, characterized in that, The valve body includes a valve housing, a shaft, and a valve core, and can realize mechanical switching and sealing functions. The valve core is disposed inside the housing and deflects under the drive of the shaft to control the flow rate in the channel.

4. A fault monitoring method for an aircraft electric heating control system based on BITE health management as described in any one of claims 1 to 3, characterized in that, Several independent electrically heated control valves installed on the water / sewage system operate independently under the control of a host computer and their own controllers. The health status of the control valves is monitored according to different fault modes, which are categorized based on the valve's structural characteristics as digital communication faults, power input faults, CAN communication faults, motor faults, valve actuation faults, and host computer connection faults. During operation, each functional component communicates with the controller in real time via CAN communication and hardwired connections. Digital communication fault monitoring: The controller determines whether digital communication is normal by testing whether the instructions can be executed correctly. If more than three arithmetic and logical operations are performed and the result is inconsistent with the expected result more than three times, it is determined to be a digital communication failure. Power input fault detection: The controller samples the power supply voltage once in each sampling cycle. If the sampled power supply voltage value is within the threshold range, the power supply is considered normal. If the sampled power supply voltage is outside the threshold range for multiple consecutive sampling cycles, the power supply input is considered faulty. CAN communication fault detection: If the CAN communication between the controller inside the control valve and the host computer is interrupted for more than the set threshold time, the CAN communication is determined to be faulty. If the communication is restored, the software will resume normal operation. Motor fault detection: The monitoring module inside the controller collects the motor's HALL signal A, HALL signal B, and HALL signal C once per sampling cycle, and performs five consecutive tests. If more than three of the collected signals output all 0 or all 1, the motor's HALL is determined to be faulty. Valve actuation fault detection: The controller checks the status of the photoelectric switch once per sampling cycle. If the extended and retracted state is detected to be effective for a certain period of time, the photoelectric switch is determined to be faulty. Host computer connection fault monitoring: The system uses four I / O interfaces to determine the identity ID and connection status of the control valve. A protocol table for high and low potential combinations of the four I / O interfaces is established to assign an identity ID to each control valve. Each time the device is connected and powered on, the control valve determines its installation location and valve identity through the data combination of the four I / O interfaces connected to the host computer. When the control valve is connected normally, the host computer will receive the control valve's identity information. When the control valve connection fails, the control valve's identity information will be lost, and the corresponding control valve fault will be indicated.

5. The fault monitoring method for an aircraft electric heating control system based on BITE health management as described in claim 4, characterized in that, The controller comprises a control module and a drive control circuit, a power conversion circuit, a power drive circuit, a position feedback signal acquisition circuit, a control circuit, and a power drive circuit. The drive control circuit includes a power secondary conversion circuit, a motor rotation direction determination circuit, a position feedback signal acquisition circuit, an extreme position determination circuit, an extreme position indication circuit, a motor control circuit, and a power control circuit. The power conversion circuit performs secondary power conversion on the aircraft's 28V power supply, converting it to +15V power to provide power to the control circuit, drive circuit, limit switches, and Hall sensors in the actuator. In the position feedback signal acquisition circuit, the position feedback of the actuator adopts a photoelectric switch assembly, which is installed on the output shaft of the actuator to detect the position of the output shaft of the actuator in real time; The limit position discrimination and indication circuit compares the collected position feedback signal with a comparator. When the position feedback signal voltage is greater than a certain value, it determines that the mechanism has reached the closed limit position and reports the closed limit position signal to the host computer. When the position feedback signal voltage is less than a certain value, it determines that the mechanism has reached the open limit position and reports the open limit position signal to the host computer. The main function of the control circuit is to collect the forward and reverse commands sent by the host computer, the position indication signals and Hall signals fed back by the actuator, and output the control commands for the permanent magnet brushless DC motor and the open or close limit position signals after performing logical combination judgments. The power drive circuit adopts a three-phase bridge inverter drive circuit to complete the driving and power inversion functions of the power components, and drive the permanent magnet brushless DC motor on the corresponding channel to work.

6. The fault monitoring method for the aircraft electric heating control system as described in claim 4, characterized in that, Each control valve installed on the water / sewage system has a consistent electrical design and is designed with error prevention through the mechanical interface of the control valve to ensure that the identity ID of each control valve corresponds one-to-one with its corresponding setting position when the host computer connects to the fault monitoring.

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