Organ perfusion temperature control method, organ perfusion temperature control system and organ perfusion temperature control equipment with hot reflux prevention dynamic constraint
By constructing a virtual temperature observation mechanism and an inner and outer dual-loop control structure, the problem of heat backflow caused by temperature control failure in the organ perfusion system was solved, achieving high-precision and high-reliability temperature control in the organ perfusion process, and improving the safety and efficiency of organ preservation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TRUEHEALTH (BEIJING) MEDICAL TECHNOLOGY CO LTD
- Filing Date
- 2026-04-17
- Publication Date
- 2026-05-15
AI Technical Summary
Traditional organ perfusion systems are prone to heat backflow due to temperature control failure, which can lead to organ damage and has poor operational safety.
A virtual temperature observation mechanism based on multi-source parameter acquisition and thermodynamic model is adopted, combined with dynamic power upper limit function and inner and outer double-loop cascade control structure, to achieve real-time accurate estimation and zone constraint of hot end temperature, prevent heat backflow risk, and improve temperature control response speed and stability.
It significantly improves the temperature control accuracy and reliability of the organ perfusion process, prevents heat backflow, and enhances the safety and efficiency of organ preservation.
Smart Images
Figure CN122030375A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of medical device technology, and more specifically, to an organ perfusion temperature control method, system, and device with dynamic constraint against heat backflow. Background Technology
[0002] Limb replantation is a crucial field in trauma surgery and microsurgery, and a vital technique in battlefield rescue. Currently, ischemic time exceeding 6 hours after limb amputation leads to irreversible muscle necrosis, nerve degeneration, and vascular endothelial damage, resulting in a replantation failure rate as high as 30%-50%. Organ transplantation is the primary treatment for patients with end-stage organ diseases; however, the shortage of organ donors is a significant global medical problem, with demand far exceeding supply. This results in a large number of patients dying while waiting for suitable organs due to deterioration of their condition or complications.
[0003] In traditional organ transplantation or limb replantation, organ or limb preservation primarily relies on static cryopreservation (e.g., ice at 4°C), which has a limited preservation time and can only slow down metabolism but cannot repair tissue damage. Hypothermic machine perfusion (HMP) mechanically oxygenates organs or limbs at low temperatures, allowing them to maintain activity during preservation and delaying the decline of their physiological functions. Its advantages include significantly extending organ preservation time, reducing damage caused by ischemia and hypoxia, and thus improving transplant success rates. Normothermic machine perfusion (NMP) technology simulates blood circulation under normal physiological conditions, perfusing transplanted organs or limbs at room temperature or near-normal temperature. It aims to extend the effective preservation time of organs or limbs, improve preservation quality, achieve repair and regeneration, and allow for pre-transplantation functional assessment.
[0004] Currently, perfusion systems primarily employ a cascade control architecture to improve response speed. The inner loop (tank temperature) is responsible for quickly eliminating internal disturbances. However, under extremely rapid cooling demands, the outer loop sends a large temperature difference command to the inner loop, causing the inner loop controller to output its maximum power (e.g., 100% PWM). When the hot end of the temperature control module experiences poor heat dissipation or power overload, Joule heating rises sharply and exceeds the Peltier cooling effect, causing heat to flow back into the cold end (i.e., "heat recirculation"), leading to system malfunction. Due to the limited space and insulation requirements inside the medical water tank, it is impossible to install a physical temperature sensor on the hot end of the temperature control module for monitoring, resulting in the controller operating blindly. This makes the perfusion system susceptible to organ damage due to temperature control failure, leading to poor operational safety. Summary of the Invention
[0005] In view of this, the present invention provides an organ perfusion temperature control method, system and device with dynamic constraint against heat backflow, in order to solve the problem that the perfusion system is prone to organ damage due to temperature control failure, resulting in poor operational safety.
[0006] In a first aspect, the present invention provides an organ perfusion temperature control method with dynamic constraint against heat backflow, applied to an organ perfusion system. The organ perfusion system includes: a storage container for storing perfusion fluid; a perfusion pump connected to the storage container and the organ via a perfusion pipeline for drawing perfusion fluid from the storage container and perfusing the organ through the perfusion pipeline; an oxygenator for oxygenating the perfusion fluid and the organ; and a temperature control module for maintaining the temperature of the organ and the perfusion fluid within a set range, the temperature control module including a water tank. The method includes: acquiring the driving signal of the temperature control module in the organ perfusion system. The system collects current information, voltage information, internal water tank temperature information, and current liquid level information in the heat exchange water tank. Based on the driving current information, voltage information, internal water tank temperature information, and preset intrinsic parameters of the temperature control module, it calculates the estimated absolute temperature of the hot end of the temperature control module. Based on the estimated absolute temperature of the hot end and a preset dynamic power upper limit function, it determines the temperature control output power of the temperature control module. Based on the estimated absolute temperature of the hot end, the internal water tank temperature information, and the liquid level information, it determines the theoretical driving power. Based on the temperature control output power and the theoretical driving power, it determines the actual output power command.
[0007] This embodiment provides an organ perfusion temperature control method with dynamic constraints to prevent thermal backflow. By constructing a virtual temperature observation mechanism based on multi-source parameter acquisition and a thermodynamic model, it achieves real-time and accurate estimation of the hot-end temperature without the need for additional hot-end sensors. Furthermore, it incorporates a dynamic power upper limit function to partition the output of the temperature control module, effectively preventing the risk of thermal backflow. Moreover, by introducing an inner and outer dual-loop cascade control structure, it separates system hysteresis from external disturbances, significantly improving the temperature control response speed, stability, and anti-interference capability. Finally, through the fusion of theoretical power and safety constraints, it achieves a balance between temperature control efficiency and system safety, thereby improving the temperature control accuracy and reliability of the organ perfusion process.
[0008] In one optional implementation, the intrinsic parameters of the temperature control module include: Seebeck coefficient. Internal resistance and thermal conductivity The estimated absolute temperature of the hot end It is calculated using the following formula: .
[0009] In one optional implementation, determining the temperature control output power of the temperature control module based on the calculated absolute temperature of the hot end and a preset dynamic power upper limit function includes: in response to the calculated absolute temperature of the hot end being less than a preset safety threshold, setting the temperature control output power of the temperature control module to full power based on the dynamic power upper limit function; in response to the calculated absolute temperature of the hot end being between the safety threshold and a preset warning threshold, the dynamic power upper limit function decreasing with increasing temperature, and increasing the cooling function of the temperature control module to full load; in response to the calculated absolute temperature of the hot end being greater than the warning threshold, setting the temperature control output power of the temperature control module to zero or at a preset power lower limit value based on the dynamic power upper limit function.
[0010] In one optional implementation, determining the actual output power command based on the temperature control output power and the feedback reference power includes: determining the actual output power command based on the smaller value between the temperature control output power and the feedback reference power.
[0011] In one optional implementation, determining the theoretical driving power based on the estimated absolute temperature of the hot end, the internal temperature information of the water tank, and the liquid level information includes: calculating a temperature difference based on the estimated absolute temperature of the hot end and the internal temperature information of the water tank; calculating a feedforward reference power based on the liquid level information; calculating a feedback reference power based on the temperature difference; and calculating the theoretical driving power based on the feedforward reference power and the feedback reference power.
[0012] In one alternative implementation, the feedforward reference power is calculated using the following formula: ,in, The effective total fluid volume is determined based on the liquid level information; the feedback reference power is calculated using the following formula: ,in, The temperature difference value, , This is the estimated absolute temperature of the hot end. This refers to the internal temperature information of the water tank.
[0013] In an optional implementation, the method further includes: in response to the theoretical driving power being greater than the temperature control output power, freezing the integral accumulator of the inner loop proportional-integral-derivative control until the calculated value of the absolute temperature of the hot end is less than a preset safety threshold.
[0014] In an optional implementation, the method further includes: in response to the liquid level information decreasing by a preset value within a preset time, locking the current integral term in the proportional-integral-derivative control, and reducing the temperature control output power to a preset ratio.
[0015] In a second aspect, the present invention provides an organ perfusion temperature control device with dynamic constraint against heat reflux, comprising: a memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the computer instructions to perform the organ perfusion temperature control method with dynamic constraint against heat reflux as described in any embodiment of the first aspect.
[0016] Thirdly, the present invention provides an organ perfusion system, comprising: a storage container for storing perfusion fluid; a perfusion pump connected to the storage container and the organ via a perfusion pipeline for drawing perfusion fluid from the storage container and perfusing the organ via the perfusion pipeline; an oxygenator for oxygenating the perfusion fluid and the organ; a temperature control module for maintaining the temperature of the organ and the perfusion fluid within a set range, wherein the temperature control module is provided with a water tank; and a main control system for executing the organ perfusion temperature control method with dynamic constraint against heat backflow as described in any embodiment of the first aspect. Attached Figure Description
[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0018] Figure 1 This is a schematic diagram of the structure of an organ perfusion system according to an embodiment of the present disclosure; Figure 2 This is a schematic flowchart of another organ perfusion temperature control method with dynamic constraint against heat backflow according to an embodiment of the present disclosure. Figure 3 This is a flowchart illustrating another organ perfusion temperature control method with dynamic constraint against heat backflow according to an embodiment of the present disclosure. Figure 4 This is a flowchart illustrating another organ perfusion temperature control method with dynamic constraint against heat backflow according to an embodiment of the present disclosure. Figure 5 This is a schematic diagram of the hardware structure of an organ perfusion temperature control device with dynamic constraint against heat backflow, according to an embodiment of this disclosure. Detailed Implementation
[0019] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0020] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0021] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0022] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0023] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.
[0024] To solve related technical problems, such as Figure 1As shown, this embodiment of the present disclosure provides an organ perfusion system, including: a perfusion pump 3, connected to an organ chamber 5 and an organ 6 via a perfusion pipeline 2. The organ 6 is placed in the organ chamber 5. Since the perfusion fluid is recycled, a storage container is not required. The perfusion pump 3 circulates the perfusion fluid through the perfusion pipeline 2, the organ chamber 5, and the organ 6, filters it through a filter plug 4, and sends it to an oxygenator 31 through the perfusion pipeline 2 (an ultraviolet sterilization device can also be provided to sterilize the perfusion fluid in the perfusion pipeline 2). The oxygenator 31 is used to oxygenate the perfusion fluid and the organ 6. An oxygen supply device 32 outputs oxygen, which is then used by the oxygenator 31 to oxygenate the perfusion fluid, thereby supplying oxygen to the organ 6.
[0025] The temperature control module 8 is used to maintain the temperature of the organ 6 and the perfusion fluid within a set range. The temperature control module 8 can act directly on the organ 6, or directly on the perfusion fluid in the perfusion pipeline, indirectly on the organ 6, or a combination of both. Specifically, the temperature control module 8 includes a semiconductor cooling chip 81, a water pump 82, a heat exchange water tank 83, a sensor signal acquisition circuit 84, a temperature sensor 85, a liquid level sensor 86, a drive circuit 87, and a cooling fan 88. Among them, the perfusion pump 3 is connected to the perfusion fluid inlet of the oxygenator 31 through the perfusion pipeline 2, and the constant temperature water in the heat exchange water tank 83 is connected to the heat exchange water inlet of the oxygenator 31 through the water pump 82. The perfusion fluid undergoes heat exchange in the heat exchange area of the oxygenator 31. After the heat exchange is completed, the perfusion fluid flows out from the perfusion fluid outlet of the oxygenator 31 and enters the organ compartment 5 to act on the organ 6; the constant temperature water flows back to the heat exchange water tank 83 from the heat exchange water outlet of the oxygenator 31. The thermoelectric cooler 81 (TEC) is the core cooling / heating regulating element of the temperature control module 8. Its main function is to cool the liquid in the heat exchange tank 83 by absorbing and releasing heat through the electric drive circuit 87 (and vice versa if necessary), creating the required low-temperature or constant-temperature conditions for organ preservation. The temperature sensor 85 detects the temperature of the heat exchange tank 83 and transmits this information to the sensor signal acquisition circuit 84. The liquid level sensor 86 detects the liquid level in the heat exchange tank 83 and transmits this information to the sensor signal acquisition circuit 84. The sensor signal acquisition circuit 84 transmits the temperature and / or liquid level information to the main control system 7. The cooling fan 88 works in conjunction with the thermoelectric cooler 81 to quickly remove the heat released from the hot end of the thermoelectric cooler 81.
[0026] The main control system 7 controls the perfusion pump 3 and the temperature control module 8 according to the perfusion parameters. During the first time period, the main control system 7 controls the temperature control module 8 to place the organ 6 in a hypothermic state, and in this hypothermic state, controls the perfusion pump 3 to stop perfusion or perform slow perfusion, thus entering the maintenance phase. The target temperature corresponding to the hypothermic state is, for example, 4-12℃. The first time period can be interpreted as the length of the maintenance phase, or as the time period indicated by a clock.
[0027] During the second time period, the main control system 7 controls the temperature control module 8 to place the organ 6 at normal or sub-normal temperature, and controls the perfusion pump 3 to perform normal perfusion actions under normal or sub-normal temperature conditions, thereby entering the normal perfusion stage. The target temperature corresponding to normal or sub-normal temperature conditions is, for example, 20-37℃. The second time period can be interpreted as the duration of the maintenance phase, or as the time period indicated by a clock.
[0028] The system is also equipped with a liquid level sensor 86 to detect the liquid level information in the organ compartment 5, so that the main control system 7 can monitor the changes in the liquid level in the organ compartment 5 at all times.
[0029] According to an embodiment of this disclosure, an organ perfusion temperature control method with dynamic constraint against heat backflow is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.
[0030] This embodiment provides an organ perfusion temperature control method with dynamic constraint against heat backflow, which can be used in the above-mentioned organ perfusion system. Specifically, it can be executed by the main control system of the organ perfusion system. Figure 2 This is a flowchart of an organ perfusion temperature control method with dynamic constraints for preventing thermal backflow, according to an embodiment of this disclosure. Figure 2 As shown, the process includes the following steps: Step S201: Collect the driving current information, voltage information, internal temperature information of the temperature control module in the organ perfusion system, and the liquid level information in the current heat exchange water tank.
[0031] In this embodiment of the disclosure, during each control cycle (e.g., sampling cycle) of the organ perfusion system operation Within the system, the main control system can collect multi-dimensional physical quantities related to heat exchange. Specific parameters collected include: the actual driving current flowing through the temperature control module. Voltage across the temperature control module And the internal temperature of the water tank, which serves as the feedback quantity for the inner loop of the cascade control. Furthermore, the liquid level information of the current circulation loop can be obtained through a liquid level sensor, and the real-time effective total fluid volume of the current circulation loop can be obtained based on this liquid level information. .
[0032] Step S202: Based on the driving current information, voltage information, water tank internal temperature information, and preset intrinsic parameters of the temperature control module, calculate the estimated value of the absolute temperature of the hot end of the temperature control module.
[0033] In this embodiment, considering the equipment insulation requirements and space limitations of the organ perfusion system, a virtual state observer based on thermodynamic energy balance is constructed in the main control system. In the circulation pipeline of the organ perfusion system, the total heat dissipated to the hot end is equal to the sum of the heat absorbed from the cold end and the input electrical power. The tracheal perfusion system utilizes the acquired actual driving current... The electrical power calculated from voltage and current, and the internal temperature of the water tank. The absolute temperature of the hot end is calculated by combining the intrinsic parameters of the temperature control module pre-stored in the microcontroller.
[0034] In some optional embodiments of this disclosure, the intrinsic parameters of the temperature control module mainly refer to the intrinsic parameters of the semiconductor refrigeration chip, primarily including the Seebeck coefficient. Internal resistance and thermal conductivity The estimated value of the absolute temperature of the hot end can be calculated using the following formula. : , in, This indicates the heat dissipation at the hot end of the organ perfusion system. Indicates the internal temperature of the water tank; This represents the actual drive current flowing through the temperature control module, and t represents time.
[0035] Step S203: Determine the temperature control output power of the temperature control module based on the calculated absolute temperature of the hot end and the preset dynamic power upper limit function.
[0036] In this embodiment of the disclosure, based on the calculated hot end temperature A nonlinear dynamic power upper limit function can be introduced. When the hot end approaches the physical heat dissipation limit, active frequency reduction intervention is implemented. The specific process includes: when When the temperature is below a preset safety threshold (e.g., 45°C), the organ perfusion system is in a safe operating zone. It can be set to 100%, allowing full-speed tracking of the target temperature and enabling the temperature control module to output full power. When When the temperature is between the safety threshold and a preset warning threshold (e.g., 65°C), the organ perfusion system is in the efficiency decay zone. The cooling effect decreases as the temperature rises, thus maximizing the cooling capacity of the temperature control module. When... When the temperature exceeds this warning threshold, the organ perfusion system is in the critical region of thermal reflux. Forcefully limit it to 0% or to a preset power lower limit to prevent heat backflow.
[0037] Through the above process, the control zone for the organ perfusion system is divided into three intervals: safe, efficiency decay, and critical. In the safe zone, the organ perfusion system is allowed to operate at full power; in the decay zone, the system's performance is mitigated by reducing the frequency and adding cooling functionality to the temperature control module; in the critical zone, power is forcibly cut off to eliminate the source of Joule heat. This forms a temperature control protection system that ensures cooling efficiency under normal conditions while completely preventing heat backflow under extreme operating conditions.
[0038] Step S204: Determine the theoretical driving power based on the calculated absolute temperature of the hot end, the internal temperature information of the water tank, and the liquid level information.
[0039] In this embodiment of the disclosure, the control objective in the organ perfusion system is the outlet temperature. The set temperature value is This temperature control module can directly heat or cool the water in the tank, changing the internal temperature of the tank. The water in the tank is then pumped to the temperature-changing zone of the oxygenator via a circulating water pump. The injection fluid undergoes heat exchange in this zone, after which the water in the tank returns, forming a cycle. Therefore, from the control command to the controlled variable (… There are two main dynamic links between them: 1. Temperature control module → The temperature control module transfers cold / heat energy to the water in the tank. This process is non-linear (the efficiency of the temperature control module is affected by the temperature difference), time-varying (it changes with the temperature of the hot end), and has a certain degree of thermal inertia.
[0040] 2. → After the water flows out of the tank, it travels through pipelines to the oxygenator, where it exchanges heat with the injection fluid before flowing back. This process involves external disturbances such as pipeline heat loss and oxygenator heat load, and due to the flow and mixing of water, there is a pure delay and a large time constant.
[0041] Traditional single-loop control directly uses the power of the temperature control module as the operating variable in an attempt to overcome all the aforementioned dynamics and disturbances. However, due to the large total lag from the temperature control module to the outlet (including thermal lag and pure delay), and the fact that thermal load disturbances occur near the output, single-loop PID control often suffers from slow response, large overshoot, and poor disturbance rejection.
[0042] In this embodiment, a second measurement point is introduced—the internal temperature of the water tank. The entire control channel is decomposed into two series loops: Inner loop (secondary loop): based on the internal temperature of the water tank As the controlled variable, the power of the temperature control module is quickly adjusted to make... Quickly follow the given value.
[0043] Outer loop (main loop): based on outlet water temperature As the controlled variable, its output serves as the setpoint for the inner loop (i.e., the target temperature of the water tank). The outlet temperature is slowly and precisely corrected.
[0044] By employing the aforementioned control method, the main external disturbances (oxygenator heat load) are isolated outside the inner loop, while the inner loop quickly overcomes internal disturbances such as the nonlinearity of the temperature control module itself and power supply fluctuations, thereby improving overall control performance. Therefore, in this control process, the theoretical drive power needs to be determined based on the calculated absolute temperature of the hot end, the internal temperature information of the water tank, and the liquid level information.
[0045] Step S205: Determine the actual output power command based on the temperature control output power and the theoretical drive power.
[0046] In this embodiment, the main control system combines the theoretical power requirement with the physical limits to determine the actual power requirement and then sends the actual power command to the temperature control module drive circuit. Determined by the minimum value selector: .
[0047] This embodiment provides an organ perfusion temperature control method with dynamic constraints to prevent thermal backflow. By constructing a virtual temperature observation mechanism based on multi-source parameter acquisition and a thermodynamic model, it achieves real-time and accurate estimation of the hot-end temperature without the need for additional hot-end sensors. Furthermore, it incorporates a dynamic power upper limit function to partition the output of the temperature control module, effectively preventing the risk of thermal backflow. Moreover, by introducing an inner and outer dual-loop cascade control structure, it separates system hysteresis from external disturbances, significantly improving the temperature control response speed, stability, and anti-interference capability. Finally, through the fusion of theoretical power and safety constraints, it achieves a balance between temperature control efficiency and system safety, thereby improving the temperature control accuracy and reliability of the organ perfusion process.
[0048] In some optional embodiments of this disclosure, step S204, the process of determining the theoretical driving power based on the calculated absolute temperature of the hot end, the internal temperature information of the water tank, and the liquid level information, mainly includes: Step 1: Calculate the temperature difference based on the estimated absolute temperature of the hot end and the internal temperature information of the water tank.
[0049] Specifically, this temperature difference is calculated using the following formula: .
[0050] Step 2: Calculate the feedforward reference power based on the liquid level information.
[0051] Specifically, the feedforward reference power is calculated using the following formula: ,in, The effective total fluid volume is determined based on liquid level information; The heat exchange efficiency coefficient; This is the set temperature value.
[0052] Step 3: Calculate the feedback reference power based on the temperature difference.
[0053] In this embodiment of the disclosure, the proportional coefficient is determined by looking up a table or dynamically calculating the liquid level L. With integral coefficient If the liquid level is extremely low, it will be automatically lowered. and To prevent overshoot; if the liquid level is high, increase the parameter to speed up the response. Differential coefficient. It is determined based on the parameter settings at full liquid level. The feedback power is... Specifically, the feedback reference power is calculated using the following formula: .
[0054] Step 4: Calculate the theoretical driving power based on the feedforward reference power and the feedback reference power.
[0055] In this embodiment, the feedforward reference power and the feedback reference power are combined to obtain the theoretical drive power. Specifically, the theoretical drive power is calculated using the following formula: .
[0056] This embodiment also provides an organ perfusion temperature control method with dynamic constraint against heat backflow, which can be used in the above-mentioned organ perfusion system. Figure 3 This is a flowchart of an organ perfusion temperature control method with dynamic constraints for preventing thermal backflow, according to an embodiment of this disclosure. Figure 3 As shown, the process includes the following steps: Step S301: Collect the driving current information, voltage information, internal temperature information of the temperature control module in the organ perfusion system, and the liquid level information in the current heat exchange water tank.
[0057] Step S302: Based on the driving current information, voltage information, water tank internal temperature information, and preset intrinsic parameters of the temperature control module, calculate the estimated value of the absolute temperature of the hot end of the temperature control module.
[0058] Step S303: Determine the temperature control output power of the temperature control module based on the calculated value of the absolute temperature of the hot end and the preset dynamic power upper limit function.
[0059] Step S304: Determine the theoretical driving power based on the calculated absolute temperature of the hot end, the internal temperature information of the water tank, and the liquid level information.
[0060] Step S305: Determine the actual output power command based on the temperature control output power and the theoretical drive power.
[0061] The above steps S301-305 are the same as those in the example. Figure 2 The steps 201-205 shown are the same. For the same parts, please refer to the corresponding parts of the previous embodiment. They will not be repeated here.
[0062] Step S306: In response to the theoretical driving power being greater than the temperature control output power, the integral accumulator of the inner loop proportional-integral-derivative control is frozen until the calculated value of the absolute temperature of the hot end is less than the preset safety threshold.
[0063] In this embodiment of the disclosure, in the inner-loop PID algorithm of cascade control, the theoretical drive power It is calculated from three parts: proportional (P), integral (I), and differential (D). The integral term (I) is used to accumulate historical errors in order to eliminate steady-state errors.
[0064] Assuming the target water temperature is 4°C and the current water temperature is 15°C, the system detects the TEC hot end temperature. The temperature spiked to 62°C (approaching the danger zone), triggering the safety mechanism in step S203, which increased the physical output limit. Forced to lock at 35%.
[0065] At this point, a conflict arises in the system's internal control process: at the physical level, the TEC can only cool slowly at 35% power. At the algorithm level, it is discovered that the water temperature is slow to drop below 4°C (an error persists), so the integral term (I) begins to continuously accumulate these errors, theoretically driving the power... It has been showing a continuous growth trend, from 80% to 100%, and may even grow to 200% or 500% internally.
[0066] When the TEC heat dissipation is alleviated and the hot-end temperature drops to a safe range of 45°C, The system will recover to 100%. If there is no protection mechanism at this point, the inner loop PID controller will directly issue the command that has just accumulated to 500%. The TEC will instantly operate at full load, causing the water temperature to drop directly below 4°C, resulting in a severe temperature overshoot. This could directly cause frostbite to detached organs during organ perfusion.
[0067] Therefore, in this embodiment of the disclosure, anti-integral saturation is achieved through the process of step S306. When the main control system detects that it is in a clamped state (i.e. If the temperature drops below the calculated absolute temperature of the hot junction, immediately pause the integration operation until the calculated absolute temperature of the hot junction is less than the preset safety threshold. When the system exits the clamping state, the integral term remains at a reasonable value, and the temperature smoothly matches the target curve.
[0068] Through the above process, an anti-integral saturation mechanism is introduced. By freezing the integral accumulation of the inner-loop PID when the temperature control output is limited (power clamping), the problem of power surge caused by abnormal accumulation of the integral term is effectively avoided, thereby preventing severe temperature overshoot when the system returns to normal operating conditions. On the one hand, it can ensure the safety of the hot end and prevent heat backflow; on the other hand, it can further improve the stability and accuracy of the temperature control process, reduce the potential risk of damage to excised organs, and significantly enhance the safety of the system.
[0069] This embodiment also provides an organ perfusion temperature control method with dynamic constraint against heat backflow, which can be used in the above-mentioned organ perfusion system. Figure 4 This is a flowchart of an organ perfusion temperature control method with dynamic constraints for preventing thermal backflow, according to an embodiment of this disclosure. Figure 4 As shown, the process includes the following steps: Step S401: Collect the driving current information, voltage information, internal temperature information of the temperature control module in the organ perfusion system, and the liquid level information in the current heat exchange water tank.
[0070] Step S402: Based on the driving current information, voltage information, water tank internal temperature information, and preset intrinsic parameters of the temperature control module, calculate the estimated value of the absolute temperature of the hot end of the temperature control module.
[0071] Step S403: Determine the temperature control output power of the temperature control module based on the calculated absolute temperature of the hot end and the preset dynamic power upper limit function.
[0072] Step S404: Determine the theoretical driving power based on the calculated absolute temperature of the hot end, the internal temperature information of the water tank, and the liquid level information.
[0073] Step S405: Determine the actual output power command based on the temperature control output power and the theoretical drive power.
[0074] The above steps S401-405 are the same as those in the example. Figure 2 The steps 201-205 shown are the same. For the same parts, please refer to the corresponding parts of the previous embodiment. They will not be repeated here.
[0075] In step S406, in response to the liquid level information decreasing by a preset value within a preset time, the current integral term in the proportional-integral-derivative control is locked, and the temperature control output power is reduced to a preset ratio.
[0076] During a typical injection process, the system's circulation loop may need to be fully loaded with 2 liters of circulating fluid. To drive the rapid cooling of this 2 liters of fluid, the PID algorithm (especially the integral term) has accumulated a significant amount of output kinetic energy.
[0077] At this point, if the doctor drains fluid or adjusts the tubing during the procedure, causing a step drop in the fluid level in the tank (a drop of a predetermined amount within a preset time, for example...), The water level drops instantly from 2 liters to 0.5 liters. At this point, without a level sensor, the PID controller will still use the high power accumulated from driving the previous 2 liters of water (e.g., 80% of the PWM) to adjust the temperature of the remaining 0.5 liters. This means that the remaining 0.5 liters of water will experience extreme temperature drops or rises within seconds (in heating conditions, this would create instantaneous high temperatures), potentially leading to a medical accident.
[0078] Therefore, in this embodiment of the disclosure, when it is detected When the rate of change exceeds the threshold, the main control system immediately executes the following process: locks the integral term, instantly resets it to zero or proportionally reduces the integral accumulator of the current PID, directly releasing the kinetic energy previously accumulated for 2 liters of water. Then, it forcibly lowers the threshold. Regardless of the current hot-end temperature, the maximum allowable power of the TEC is forcibly increased. Reduce the pressure (e.g., to 20%). Through the above process, the tracheal infusion system adapts to the new low thermal inertia environment by reusing the process in step S204 under the new minimal water volume, and then gradually increases the power.
[0079] Through the above process, an adaptive protection control process based on sudden liquid level changes is introduced. By locking or reducing the PID integral term when a rapid decrease in circulating liquid volume is detected, and simultaneously reducing the temperature control output power, the problem of excessive control inertia caused by a sudden decrease in heat capacity is effectively eliminated, avoiding the risk of drastic local temperature fluctuations or instantaneous overheating / overcooling. This enables the organ perfusion system to quickly adapt to different liquid volume conditions, significantly improving the safety, stability, and robustness of the temperature control process to sudden operational scenarios, and reducing the risks of medical operations.
[0080] This disclosure also provides an organ perfusion temperature control device with dynamic constraint against heat backflow. Please refer to [link to relevant documentation]. Figure 5 , Figure 5 This is a schematic diagram of the structure of an organ perfusion temperature control device with dynamic constraint against heat backflow, provided in an optional embodiment of the present invention. Figure 5As shown, the organ perfusion temperature control device with dynamic constraint against thermal reflux includes one or more processors 10, a memory 20, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components communicate with each other via different buses and can be mounted on a common motherboard or otherwise as required. The processor can process instructions executed within the organ perfusion temperature control device with dynamic constraint against thermal reflux, including instructions stored in or on memory to display graphical information of a GUI on an external input / output device (such as a display device coupled to the interface). In some alternative embodiments, multiple processors and / or multiple buses can be used with multiple memories and multiple memory sets, if desired. Similarly, multiple organ perfusion temperature control devices with dynamic constraint against thermal reflux can be connected, each device providing some of the necessary operations (e.g., as a server array, a set of blade servers, or a multiprocessor system). Figure 5 Take a processor 10 as an example.
[0081] Processor 10 may be a central processing unit, a network processor, or a combination thereof. Processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GDA), or any combination thereof.
[0082] The memory 20 stores instructions executable by at least one processor 10 to cause the at least one processor 10 to perform the method shown in the above embodiments.
[0083] The memory 20 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function. The data storage area may store data created based on the use of the organ perfusion temperature control device with thermal reflux protection dynamic constraints. Furthermore, the memory 20 may include high-speed random access memory and may also include non-transient memory, such as at least one disk storage device, flash memory device, or other non-transient solid-state storage device. In some alternative embodiments, the memory 20 may optionally include memory remotely located relative to the processor 10, which can be connected to the organ perfusion temperature control device with thermal reflux protection dynamic constraints via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.
[0084] The memory 20 may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk or solid-state drive; the memory 20 may also include a combination of the above types of memory.
[0085] The organ perfusion temperature control device with dynamic constraint against heat backflow also includes a communication interface 30 for communicating with other devices or communication networks.
[0086] This disclosure also provides a computer-readable storage medium in which the methods described in this disclosure can be implemented in hardware or firmware, or implemented as recordable on a storage medium, or implemented as computer code originally stored on a remote storage medium or a non-transitory machine-readable storage medium and subsequently stored on a local storage medium after being downloaded over a network. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium may be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium may also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code that, when accessed and executed by the computer, processor, or hardware, implements the methods shown in the above embodiments.
[0087] A portion of this invention can be applied as a computer program product, such as computer program instructions, which, when executed by a computer, can invoke or provide the methods and / or technical solutions according to the invention through the operation of the computer. Those skilled in the art will understand that the forms in which computer program instructions exist in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executing the instructions, or the computer compiling the instructions and then executing the corresponding compiled program, or the computer reading and executing the instructions, or the computer reading and installing the instructions and then executing the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to a computer.
[0088] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.
Claims
1. An organ perfusion temperature control method with dynamic constraint against heat backflow, applied to an organ perfusion system, characterized in that, The organ perfusion system includes: a perfusion pump connected to the organ chamber and the organ via a perfusion pipeline for perfusing the organ through the perfusion pipeline; an oxygenator for oxygenating the perfusion fluid and the organ; and a temperature control module for maintaining the temperature of the organ and the perfusion fluid within a set range, wherein the temperature control module is equipped with a water tank; the method includes: Collect drive current information, voltage information, internal temperature information of the temperature control module in the organ perfusion system, and liquid level information in the current heat exchange water tank. Based on the driving current information, voltage information, water tank internal temperature information, and preset intrinsic parameters of the temperature control module, the estimated value of the absolute temperature of the hot end of the temperature control module is calculated. The temperature control output power of the temperature control module is determined based on the calculated absolute temperature of the hot end and the preset dynamic power upper limit function. The theoretical driving power is determined based on the calculated absolute temperature of the hot end, the internal temperature information of the water tank, and the liquid level information. The actual output power command is determined based on the temperature control output power and the theoretical drive power.
2. The method according to claim 1, characterized in that, The intrinsic parameters of the temperature control module include: Seebeck coefficient. Internal resistance and thermal conductivity The estimated absolute temperature of the hot end It is calculated using the following formula: ， in, Indicates the internal temperature of the water tank; This represents the actual drive current flowing through the temperature control module, and t represents time.
3. The method according to claim 1, characterized in that, The determination of the temperature control output power of the temperature control module based on the calculated value of the absolute temperature of the hot end and the preset dynamic power upper limit function includes: In response to the calculated absolute temperature of the hot end being less than a preset safety threshold, the temperature control output power of the temperature control module is set to full power based on the dynamic power upper limit function; In response to the calculated absolute temperature of the hot end being between the safety threshold and the preset warning threshold, the dynamic power upper limit function decreases as the temperature increases, and the cooling function of the temperature control module is increased to full load. In response to the calculated absolute temperature of the hot end being greater than the warning threshold, the temperature control output power of the temperature control module is set to zero or to a preset lower power limit based on the dynamic power upper limit function.
4. The method according to claim 1, characterized in that, The command to determine the actual output power based on the temperature control output power and the feedback reference power includes: The actual output power command is determined based on the smaller of the temperature control output power and the feedback reference power.
5. The method according to claim 1, characterized in that, The determination of the theoretical driving power based on the calculated absolute temperature of the hot end, the internal temperature information of the water tank, and the liquid level information includes: The temperature difference is calculated based on the estimated absolute temperature of the hot end and the internal temperature information of the water tank. Calculate the feedforward reference power based on the liquid level information; The feedback reference power is calculated based on the temperature difference. The theoretical driving power is calculated based on the feedforward reference power and the feedback reference power.
6. The method according to claim 5, characterized in that, The feedforward reference power is calculated using the following formula: ,in, The effective total fluid volume is determined based on the liquid level information; The heat exchange efficiency coefficient; The feedback reference power is calculated using the following formula: ,in, The temperature difference value, , This is the estimated absolute temperature of the hot end. This refers to the internal temperature information of the water tank.
7. The method according to any one of claims 1-6, characterized in that, The method further includes: In response to the theoretical driving power being greater than the temperature control output power, the integral accumulator of the inner loop proportional-integral-derivative control is frozen until the calculated value of the absolute temperature of the hot end is less than the preset safety threshold.
8. The method according to any one of claims 1-6, characterized in that, The method further includes: In response to the liquid level information decreasing by a preset value within a preset time, the current integral term in the proportional-integral-derivative control is locked, and the temperature control output power is reduced to a preset ratio.
9. An organ perfusion temperature control device with dynamic constraint against heat backflow, characterized in that, include: The system includes a memory and a processor, which are interconnected. The memory stores computer instructions, and the processor executes the computer instructions to perform the organ perfusion temperature control method with dynamic constraint against thermal backflow as described in any one of claims 1 to 8.
10. An organ perfusion system, characterized in that, include: A storage container for storing perfusion fluid; a perfusion pump connected to the storage container and the organ via a perfusion pipeline for drawing perfusion fluid from the storage container and perfusing the organ via the perfusion pipeline; an oxygenator for oxygenating the perfusion fluid and the organ; a temperature control module for maintaining the temperature of the organ and the perfusion fluid within a set range, the temperature control module being equipped with a water tank; and a main control system for executing the organ perfusion temperature control method with dynamic constraint against heat backflow as described in any one of claims 1 to 8.