A silicon carbide device active thermal management system based on aloe vera stomatal cell microvalve and a control method

Abstract

This invention discloses an active thermal management system and control method for silicon carbide devices based on aloe vera-inspired stomatal cell microvalves, belonging to the field of active thermal management technology for silicon carbide devices. The active thermal management system includes a hygroscopic phase change working fluid module and a stomatal cell-inspired intelligent control module. The hygroscopic phase change working fluid module includes a heat sink body, a hygroscopic salt solution contained within the heat sink body, and a porous permeable membrane covering the surface of the hygroscopic salt solution for basic passive heat dissipation. The stomatal cell-inspired intelligent control module includes a stomatal cell-inspired microvalves array and a detection and control unit, simulating the diurnal rhythm and stress response mechanism of biological stomata. By adjusting the number of microvalves opening and closing, the water vapor discharge rate is precisely controlled, thereby controlling the heat exchange rate. This invention significantly reduces the average junction temperature of silicon carbide devices and greatly suppresses temperature cycling stress, effectively delaying thermomechanical fatigue failure.

Description

Technical Field

[0001] This invention relates to the field of active thermal management of silicon carbide devices, specifically to a micro-valve that mimics the stomata of aloe vera, using lithium bromide aqueous solution as the thermal management medium, and a thermal management system and control method for controlling the junction temperature of silicon carbide devices. It is suitable for active thermal management of silicon carbide devices to reduce junction temperature fluctuations. Background Technology

[0002] As the global energy transition drives the leapfrog development of power electronic systems toward extremely high power density, ultra-high frequency switching and deep integration, third-generation wide-bandgap semiconductor power devices, represented by silicon carbide (SiC) and gallium nitride (GaN), have significantly improved energy efficiency and switching speed. However, they have also caused more severe transient thermal shocks and high-frequency periodic junction temperature fluctuations under complex dynamic load conditions. According to the Coffin-Manson fatigue model, the large temperature cycling stress accelerates the thermomechanical fatigue failure process, such as chip solder layer aging and bond wire peeling, which seriously restricts the reliability of equipment throughout its entire life cycle. However, current mainstream thermal management solutions all suffer from irreconcilable structural defects when addressing this challenge: passive heat dissipation technologies (such as traditional fins, heat pipes, or phase change materials) are limited by their inherent static thermal resistance characteristics and passive response mechanisms, exhibiting significant thermal inertia lag when faced with millisecond-level thermal load changes, failing to dynamically match changes in heat flux density, resulting in severe overshoot and undershoot phenomena in junction temperature; while active heat dissipation technologies (such as forced air cooling, liquid cooling circulation, or thermoelectric cooling) introduce actuators for intervention, but their reliance on macroscopic mechanical components such as motors and pumps for regulation not only results in insufficient dynamic bandwidth due to large rotational inertia, making it difficult to follow rapid thermal transients, but also injects significant current harmonics and conducted noise into the system through the high-frequency pulse width modulation (PWM) signal generated by its drive circuit, deteriorating the electromagnetic compatibility (EMC) environment and generating strong control intrusion, interfering with the precision gate drive signal through ground coupling, and such systems mostly indirectly calculate junction temperature based on the package temperature, which is limited by phase delay and amplitude attenuation caused by package thermal capacity, resulting in distorted state observation and low closed-loop control accuracy. Therefore, there is an urgent need for a new thermal management paradigm that can deeply integrate efficient latent heat utilization of micro-nano scale phase change heat transfer, rapid dynamic response of biomimetic microfluidics, and non-invasive high-precision online junction temperature reconstruction. This paradigm aims to achieve decoupled and precise control of average junction temperature suppression and junction temperature fluctuation smoothing of power devices while completely avoiding electromagnetic interference and control intrusion risks, thereby breaking through the thermal design bottleneck of high-reliability power electronic equipment. Summary of the Invention

[0003] The purpose of this invention is to overcome the above-mentioned problems and propose an active thermal management system and control method for silicon carbide devices based on aloe vera-inspired stomatal cell microvalve. This system can effectively and significantly reduce junction temperature fluctuations of silicon carbide devices while dissipating heat, thereby improving the working capacity and service life of silicon carbide devices.

[0004] An active thermal management system for silicon carbide devices based on aloe vera-inspired stomatal cell microvalve, comprising:

[0005] The hygroscopic phase change working fluid module includes a heat sink body, a hygroscopic salt solution contained within the heat sink body, and a porous breathable membrane covering the surface of the hygroscopic salt solution.

[0006] The biomimetic pore intelligent control module includes a biomimetic pore microvalve array and a detection and control unit. The biomimetic pore microvalve array covers the side of the porous breathable membrane away from the hygroscopic salt solution, and the biomimetic pore microvalve array communicates with the detection and control unit.

[0007] The hygroscopic phase change working fluid module is located above the silicon carbide device.

[0008] In the above technical solution, the hygroscopic salt solution is a lithium bromide aqueous solution with a mass fraction of 40.4%.

[0009] In the above technical solution, the porous breathable membrane is made of polytetrafluoroethylene material.

[0010] In the above technical solution, the simulated air vent microvalve array is composed of several microvalves. Each microvalve consists of an air vent, an elastic reset mechanism, and a microcapacitor, and each microvalve has a unique physical address code. The elastic reset mechanism is specifically a micro spring located above the air vent, and the microcapacitor is attached to the upper part of the elastic reset mechanism.

[0011] In the above technical solution, the detection and control unit includes a detection circuit, a processor, and a drive circuit. The detection circuit acquires the saturation on-state voltage drop and current signal of the silicon carbide device through a front-end acquisition unit. The hardware unit of the processor includes a digital signal processor (DSP), an ADC circuit, a memory, and a GPIO input / output interface. The DSP executes the calculation of all formulas in the control method. The ADC circuit receives the signal from the detection circuit and performs analog-to-digital conversion. The memory is used to store preset models and equations. The GPIO input / output interface outputs address addressing instructions to the drive circuit. The drive circuit receives the processor instructions, performs signal isolation, digital-to-analog conversion, and power amplification, and outputs a drive voltage signal to drive the switch of the circuit containing the miniature capacitor to close, thereby controlling the opening and closing of the biomimetic gas vent micro-valve.

[0012] A control method for an active thermal management system of silicon carbide devices based on aloe vera-inspired stomatal cell microvalve:

[0013] The detection circuit collects the saturation on-state voltage drop and current of the silicon carbide device under steady-state conduction. After processing by the ADC circuit, the real-time junction temperature is calculated using the voltage-current-junction temperature mapping model of the silicon carbide device in the memory.

[0014] The processor determines whether the real-time junction temperature of the silicon carbide device is within the junction temperature range. If the real-time junction temperature is not within the junction temperature range, the state of the biomimetic vent microvalve array is not changed. If the real-time junction temperature is within the junction temperature range, the processor determines the total heat generated by the silicon carbide device Q within time Δt based on the microvalve number-thermal resistance network equation. gen =Total heat dissipation of the thermal management system Q diss Determine the number n of microvalves that need to be opened in the microvalves array;

[0015] The specific action of the micro-valve is determined by n, and a set of driving voltage vector signals is generated and sent to the driving circuit through the GPIO input / output interface to control the opening and closing of the corresponding micro-valve.

[0016] Furthermore, the voltage-current-junction temperature mapping model of the silicon carbide device is as follows:

[0017]

[0018] Among them, V ce(on) (t) represents the saturation on-state voltage drop of the silicon carbide device under steady-state conduction, acquired by the low-frequency calibration channel of the detection circuit; I d (t) represents the steady-state current of the silicon carbide device under conduction conditions, which is acquired in real time by the high-frequency feedforward channel of the detection circuit; T j (t) represents the real-time junction temperature of the silicon carbide device, and a, b, c, and d are experimentally calibrated coefficients.

[0019] Furthermore, the microvalve number-thermal resistance network equation is as follows: , where R fixed For solid thermal resistance, R v (n) is the variable thermal resistance, R fixed =R js +R sf R js R is the thermal resistance from the silicon carbide device to the heat sink body. sf The thermal resistance for convective heat transfer from the radiator body to the hygroscopic salt solution. r h Let n be the equivalent thermal resistance of a single microvalve, n≤N, where N is the number of all microvalves in the biomimetic orifice microvalve array.

[0020] Furthermore, the total heat generated by the silicon carbide device Q within time Δt. gen for:

[0021]

[0022] i=1, 2, 3…

[0023] Among them, P loss The heat generated by the silicon carbide device within the time interval Δt;

[0024] The total heat dissipation Q of the thermal management system within time Δt diss for:

[0025]

[0026] Among them, T amb The ambient temperature.

[0027] Furthermore, the number of microvalves that need to be opened in the microvalves array .

[0028] The active thermal management system and control method for silicon carbide devices based on aloe vera-inspired stomatal cell microvalve proposed in this invention have the following beneficial effects:

[0029] 1. Effectively suppresses thermomechanical fatigue: Utilizing the latent heat of liquid-gas phase change in hygroscopic salt solutions as the primary heat dissipation pathway, it overcomes the limitations of traditional sensible heat exchange, reducing the average junction temperature of silicon carbide devices and eliminating localized hot spots. By dynamically matching the heat dissipation rate with the instantaneous heat generation rate, it suppresses junction temperature fluctuations, alleviates solder layer fatigue and bond wire peeling caused by the Coffin-Manson effect, and extends the service life of silicon carbide devices.

[0030] 2. Solving the problem of thermal inertia hysteresis: Abandoning traditional macroscopic mechanical components such as fans, it adopts an electrostatically driven, biomimetic air-hole microvalve array with no mechanical rotational inertia and has microsecond-level fast response capability. Combined with an adaptive model predictive control algorithm, it can detect the thermal transients of silicon carbide devices under dynamic loads in real time, solving the problem of temperature overshoot and undershoot caused by thermal inertia in traditional passive heat dissipation.

[0031] 3. Non-intrusive linear drive: Employing a high-voltage linear power amplifier avoids current harmonics and conducted noise generated by high-frequency switching. When adjusting the heat dissipation rate, it does not inject interference signals into the silicon carbide device and the main circuit, eliminating electromagnetic interference of active heat dissipation control on the gate drive signal of the silicon carbide device and ensuring the signal integrity of the main control circuit.

[0032] 4. High-precision junction temperature reconstruction: The dual-channel synchronous sampling of low-frequency saturated on-state voltage drop calibration and high-frequency current feedforward eliminates the phase delay caused by the thermal capacitance of the package, and realizes high-precision reconstruction of the true junction temperature inside the silicon carbide device. This provides accurate feedback variables for closed-loop control and solves the parameter drift problem in long-term operation.

[0033] 5. High system robustness: The hygroscopic salt solution possesses a unique breathing-type concentration self-balancing characteristic, which allows it to spontaneously absorb moisture from the environment under low-load conditions, solving the maintenance problem of traditional phase change materials' drying failure. Simultaneously, the microvalve adopts a normally open electrostatic design, automatically opening in the event of a fault or power outage, simplifying system design and improving system safety and long-term operational robustness. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the active thermal management system described in this invention;

[0035] Figure 2 This is a schematic diagram illustrating the working principle of the hygroscopic salt solution described in this invention.

[0036] Figure 3(a) is a schematic diagram of the open state of the biomimetic gas vent micro-valve described in this invention;

[0037] Figure 3(b) is a schematic diagram of the closed state of the biomimetic gas vent micro-valve described in this invention;

[0038] Figure 4 This invention refers to the biomimetic gas vent microvalve array.

[0039] Figure 5 This is the execution logic of the digital signal processor (DSP) described in this invention;

[0040] Figure 6 This is the voltage-current-junction temperature mapping model for the silicon carbide device described in this invention;

[0041] Figure 7 This is a flowchart of the active thermal management system for suppressing junction temperature fluctuations according to the present invention.

[0042] Figure 8 The figure shows the experimental results of the active thermal management system described in this invention. Detailed Implementation

[0043] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0044] like Figure 1 As shown, this embodiment discloses an active thermal management system for silicon carbide devices based on aloe vera-inspired stomatal cell microvalve, including a hygroscopic phase change working fluid module and an aloe vera-inspired intelligent stomata control module, with the hygroscopic phase change working fluid module located above the silicon carbide device. Figure 2As shown, the hygroscopic phase change working fluid module includes a heat sink body, a hygroscopic salt solution contained within the heat sink body, and a porous breathable membrane covering the surface of the hygroscopic salt solution; the biomimetic pore intelligent control module includes a biomimetic pore microvalve array and a detection and control unit. The biomimetic pore microvalve array covers the side of the porous breathable membrane away from the hygroscopic salt solution, and the biomimetic pore microvalve array communicates with the detection and control unit.

[0045] In the hygroscopic phase change working fluid module, the hygroscopic salt solution is a lithium bromide aqueous solution with a mass fraction of 40.4%. Under high concentration conditions, it absorbs heat through water evaporation, and under low concentration conditions, it autonomously absorbs moisture from the ambient air to maintain concentration balance. The porous breathable membrane is made of polytetrafluoroethylene (PTFE) material, which has hydrophobic and breathable properties. It can both block the leakage of lithium bromide aqueous solution and prevent the overflow of corrosive vapors, and allow water vapor to pass through in both directions.

[0046] In the biomimetic vent intelligent control module, the biomimetic vent microvalve array consists of several microvalves, employing a biomimetic topology design based on energy barrier control. Each microvalve comprises an vent, an elastic reset mechanism, and a microcapacitor, as shown in Figures 3(a) and 3(b), and each microvalve has a unique physical address code. The elastic reset mechanism is specifically a micro-spring located above the vent, with the microcapacitor attached above it. Multiple microvalves are arranged in an array, as shown... Figure 4 As shown, the microvalves are encoded, and the corresponding number and position of microvalves are accurately opened by the drive signal. The microvalves have a normally conducting open state and a voltage-driven closed state. In the resting state without external drive voltage, the elastic reset mechanism overcomes the capacitive stress based on the preset stress, causing the stomata to open, simulating the passive opening mechanism of aloe vera stomata cells in a low-temperature environment, forming a normal heat dissipation channel; when the switch in the circuit where the microcapacitor is located is turned on, the power supply applies a preset threshold drive voltage to the microcapacitor, and the microcapacitor deforms under the action of electrostatic force, overcoming the preset stress of the elastic reset mechanism, and sealing the stomata downward, thereby realizing the stomata closure, simulating the active closing mechanism of aloe vera stomata cells in a high-heat environment, to block the airflow channel. The detection and control unit includes a detection circuit, a processor and a drive circuit. The detection circuit acquires the saturation conduction voltage drop and current signal of the silicon carbide device through the front-end acquisition unit; the hardware unit of the processor includes a digital signal processor (DSP), an ADC circuit, a memory and a GPIO input / output interface. The DSP executes all formula digital calculations in the control method ( Figure 5The ADC circuit receives signals from the detection circuit and performs analog-to-digital conversion. The memory is used to store preset models and equations. The GPIO input / output interface sends address addressing instructions to the drive circuit. The drive circuit receives processor instructions, performs signal isolation, digital-to-analog conversion and power amplification, and outputs a high-precision analog drive voltage signal to drive the switch of the circuit containing the micro capacitor to close and control the opening and closing of the biomimetic gas vent micro valve array.

[0047] This embodiment also discloses the control method of the above-mentioned active thermal management system for silicon carbide devices based on aloe vera-inspired stomatal cell microvalve, including the following steps:

[0048] (1) Construct the above-mentioned active thermal management system for silicon carbide devices based on micro-valve of aloe vera stomata cells.

[0049] (2) A physical thermal management platform including a hygroscopic salt solution and a micro-valve array with biomimetic pores is constructed. The latent heat of liquid-gas phase change of the salt solution is used as the main heat dissipation path. During system initialization, all micro-valves are kept open by the preset stress of the elastic reset mechanism. When the silicon carbide device generates Joule heat, the heat is conducted to the lithium bromide aqueous solution to induce liquid-gas phase change. The generated high-temperature water vapor is driven by the concentration gradient and freely dissipates into the ambient air through the porous breathable membrane to achieve basic passive heat dissipation.

[0050] (3) The detection circuit performs synchronous sampling through the low-frequency calibration channel and the high-frequency feedforward channel. The low-frequency calibration channel collects the saturation on-state voltage drop V of the silicon carbide device under steady-state conduction. ce(on) (t), the high-frequency feedforward channel acquires the dynamic waveform of the current in real time. d (t), the dual-channel synchronous sampling technology effectively eliminates the phase delay caused by the thermal capacitance of the package, ensuring millisecond-level accuracy.

[0051] (4) Based on the fact that the saturation on-state voltage drop of silicon carbide devices exhibits a certain functional fitting relationship with the junction temperature, experiments were conducted. Under the condition that the external temperature and other conditions remain unchanged, the on-state voltage drop was artificially changed, and the corresponding junction temperature was measured. However, since there is a coupling relationship between the voltage and current of silicon carbide devices, the voltage change will be affected by the current. Therefore, it is necessary to combine the real-time acquisition of the current I. d (t) Decoupling is performed to obtain a more accurate voltage-junction temperature relationship. Through calibration, a voltage-current-junction temperature mapping model for silicon carbide devices is established:

[0052]

[0053] Among them, T j (t) represents the real-time junction temperature of the silicon carbide device, where a, b, c, and d are experimentally calibrated coefficients. The voltage-current-junction temperature mapping model of the silicon carbide device described above is stored in memory and used to obtain the real-time junction temperature of the device; it is abbreviated as: .

[0054] The detection circuit re-acquires real-time saturation on-state voltage drop and current, processes them through the ADC circuit, and then utilizes the mapping model in memory. Calculations were performed to obtain a high-precision real-time junction temperature T. j .like Figure 6 As shown, in this embodiment, a voltage-current-junction temperature mapping model for silicon carbide devices is established, providing an accurate reference relationship for subsequently determining the number of micro-valve openings.

[0055] (5) Assuming the salt solution concentration, volume, and environmental conditions are constant, the path from the heat source (i.e., the silicon carbide device) to the air is divided into solid thermal resistance and variable thermal resistance. Solid thermal resistance includes the conductive thermal resistance from the silicon carbide device to the heat sink body and the convective heat transfer thermal resistance from the heat sink body to the salt solution. The conductive thermal resistance from the silicon carbide device to the heat sink body is determined by the thermal conductivity and geometric dimensions of the heat sink body material, and is denoted as R. js The convective heat transfer resistance from the radiator body to the salt solution is determined by the material and concentration of the salt solution, and is denoted as R. sf Therefore, the solid thermal resistance is R. fixed =R js +R sf The variable thermal resistance represents the change in thermal resistance caused by different numbers of microvalves opening and closing. Let the equivalent thermal resistance of a single microvalves be r. h When n microvalves open simultaneously, it is equivalent to n equivalent thermal resistances connected in parallel, therefore the variable thermal resistance... Where n ≤ N, and N is the number of all microvalves in the biomimetic vent microvalves array. The heat flow path of the thermal management system is abstracted as a one-dimensional series-parallel thermal resistance network, thereby establishing the microvalves number-thermal resistance network equation: .

[0056] (6) Due to the delay in heat transfer, to simplify the calculation, t1 is set as the current time, and the time interval Δt is the reciprocal of the detection frequency of the low-frequency channel in the detection circuit, i.e. f is the detection frequency of the low-frequency channel of the detection circuit. The processor receives the voltage and current collected by the ADC circuit at time t1, and calculates the total heat generated by the silicon carbide device Q during the time interval Δt according to the following formula. gen :

[0057] i=1, 2, 3…

[0058]

[0059] Among them, P loss The heat generated by the device during the time interval Δt is the heat output power.

[0060] Without considering drastic changes in device voltage and current, the total heat generated calculated using the voltage and current at time t1 approximates the actual total heat generated over the time interval Δt. The processor, combining the microvalve number-thermal resistance network equation, calculates the total heat dissipation Q of the thermal management system over the time interval Δt using the following formula. diss :

[0061]

[0062] Among them, T amb The ambient temperature can be directly measured.

[0063] The total heat generated by the silicon carbide device within time Δt is set to be equal to the total heat dissipation Q of the thermal management system. gen =Q diss In other words, the heat dissipation of the thermal management system offsets the heat generated by the silicon carbide device, thus keeping the real-time junction temperature constant. Based on the microvalve number-thermal resistance network equation, and combined with Q... gen =Q diss , and thus 'n' represents the number of microvalves in the microvalve array that need to be opened during the time interval t1→t1+Δt. At the next moment, t2=t1+Δt, the saturation on-state voltage drop and current of the silicon carbide device under steady-state conduction are re-acquired, processed by the ADC circuit, and then mapped using the memory model. Calculate the real-time junction temperature T j Simultaneously calculate P loss Substituting this into the formula for n, we obtain the number of microvalves that need to be opened during the time interval t2→t2+Δt, continuing this process until the silicon carbide device stops working and no longer generates heat. When P loss After the value remains at 0 for a certain period of time, the processor determines that the silicon carbide device has stopped working, and the system returns to its initial state.

[0064] (7) Because each microvalve has a unique physical address code, the processor calls the internally stored address mapping table, selects the specific microvalve to perform the action from the address based on n, and generates a set of drive voltage vector signals S=[s1,s2,….,sN], si∈{0,1}, where logic 1 represents a high level, i.e., voltage is applied; logic 0 represents a low level, i.e., no voltage is applied. The drive voltage vector signals are sent to the drive circuit through the GPIO input / output interface. Figure 7 The processor's method flow shown illustrates the closed-loop process of the system.

[0065] (8) Set the target junction temperature T based on the characteristics of the silicon carbide device and its operating environment. target and the junction temperature range [T] based on this. low ,T high ], where T low =0.9T target Thigh =1.1T target When a silicon carbide device starts working, the processor determines whether the real-time junction temperature of the silicon carbide device is within the junction temperature range, i.e., T. low <T j (t) <T high If the real-time junction temperature is not within the junction temperature range, the processor does not change the state of the microvalve array. If the real-time junction temperature is within the junction temperature range, the processor controls the number of microvalves to be opened according to n in (6) until the silicon carbide device stops working.

[0066] Through the aforementioned high-frequency intelligent control of biomimetic vents, the system dynamically matches the instantaneous heat generation and dissipation rates of silicon carbide devices, suppressing junction temperature fluctuations to a minimum, thereby achieving isothermal operation of power devices and extending their thermal fatigue life. For example... Figure 8 As shown in the experimental results, the junction temperature fluctuation amplitude is significantly reduced under typical dynamic load conditions, and the feasibility of the active thermal management system is fully verified.

[0067] The above embodiments are only used to illustrate the technical ideas and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The scope of protection of the present invention is not limited to the above embodiments. Therefore, all equivalent changes or modifications made based on the principles and design ideas disclosed in the present invention are within the scope of protection of the present invention.

Claims

1. An active thermal management system for silicon carbide devices based on aloe vera-inspired stomatal cell microvalve, characterized in that, include: The hygroscopic phase change working fluid module includes a heat sink body, a hygroscopic salt solution contained within the heat sink body, and a porous breathable membrane covering the surface of the hygroscopic salt solution. The biomimetic pore intelligent control module includes a biomimetic pore microvalve array and a detection and control unit. The biomimetic pore microvalve array covers the side of the porous breathable membrane away from the hygroscopic salt solution, and the biomimetic pore microvalve array communicates with the detection and control unit. The hygroscopic phase change working fluid module is located above the silicon carbide device.

2. The active thermal management system for silicon carbide devices based on aloe vera-inspired stomatal cell microvalve according to claim 1, characterized in that, The hygroscopic salt solution is a lithium bromide aqueous solution with a mass fraction of 40.4%.

3. The active thermal management system for silicon carbide devices based on aloe vera-inspired stomatal cell microvalve according to claim 1, characterized in that, The porous breathable membrane is made of polytetrafluoroethylene material.

4. The active thermal management system for silicon carbide devices based on aloe vera-inspired stomatal cell microvalve according to claim 1, characterized in that, The simulated vent microvalve array consists of several microvalve components. Each microvalve comprises a vent, an elastic reset mechanism, and a microcapacitor, and each microvalve has a unique physical address code. The elastic reset mechanism is specifically a micro spring located above the vent, and the microcapacitor is attached to the upper part of the elastic reset mechanism.

5. The active thermal management system for silicon carbide devices based on aloe vera-inspired stomatal cell microvalve according to claim 1, characterized in that, The detection and control unit includes a detection circuit, a processor, and a drive circuit. The detection circuit acquires the saturation on-state voltage drop and current signal of the silicon carbide device through a front-end acquisition unit. The hardware unit of the processor includes a digital signal processor (DSP), an ADC circuit, a memory, and a GPIO input / output interface. The DSP executes the calculation of all formulas in the control method. The ADC circuit receives the signal from the detection circuit and performs analog-to-digital conversion. The memory is used to store preset models and equations. The GPIO input / output interface sends address addressing instructions to the drive circuit. The drive circuit receives the processor instructions, performs signal isolation, digital-to-analog conversion, and power amplification, and outputs a drive voltage signal to drive the switch of the circuit containing the miniature capacitor to close, thereby controlling the opening and closing of the biomimetic gas vent micro-valve.

6. A control method for an active thermal management system of a silicon carbide device based on the aloe vera stomatal cell microvalve described in any one of claims 1-5, characterized in that: The detection circuit collects the saturation on-state voltage drop and current of the silicon carbide device under steady-state conduction. After processing by the ADC circuit, the real-time junction temperature is calculated using the voltage-current-junction temperature mapping model of the silicon carbide device in the memory. The processor determines whether the real-time junction temperature of the silicon carbide device is within the junction temperature range. If the real-time junction temperature is not within the junction temperature range, the state of the biomimetic vent microvalve array is not changed. If the real-time junction temperature is within the junction temperature range, the processor determines the total heat generated by the silicon carbide device Q within time Δt based on the microvalve number-thermal resistance network equation. gen =Total heat dissipation of the thermal management system Q diss Determine the number n of microvalves that need to be opened in the microvalves array; The specific action of the micro-valve is determined by n, and a set of driving voltage vector signals is generated and sent to the driving circuit through the GPIO input / output interface to control the opening and closing of the corresponding micro-valve.

7. The control method according to claim 6, characterized in that, The voltage-current-junction temperature mapping model of the silicon carbide device is as follows: Among them, V ce(on) (t) represents the saturation on-state voltage drop of the silicon carbide device under steady-state conduction, acquired by the low-frequency calibration channel of the detection circuit; I d (t) represents the steady-state current of the silicon carbide device under conduction conditions, which is acquired in real time by the high-frequency feedforward channel of the detection circuit; T j (t) represents the real-time junction temperature of the silicon carbide device, and a, b, c, and d are experimentally calibrated coefficients.

8. The control method according to claim 7, characterized in that, The microvalve number-thermal resistance network equation is as follows: , where R fixed For solid thermal resistance, R v (n) is the variable thermal resistance, R fixed =R js +R sf R js R is the thermal resistance from the silicon carbide device to the heat sink body. sf The thermal resistance for convective heat transfer from the radiator body to the hygroscopic salt solution. r h Let n be the equivalent thermal resistance of a single microvalve, n≤N, where N is the number of all microvalves in the biomimetic orifice microvalve array.

9. The control method according to claim 8, characterized in that, The total heat generated by the silicon carbide device within time Δt is Q gen for: ，i=1，2，3… Among them, P loss The heat generated by the silicon carbide device within the time interval Δt; The total heat dissipation Q of the thermal management system within time Δt diss for: Among them, T amb The ambient temperature.

10. The control method according to claim 9, characterized in that, Number of microvalves that need to be opened in a microvalves array .

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