An automatically regulated heat dissipation system and method

Abstract

The application relates to an automatic adjusting heat dissipation system and method, which is used for heat dissipation of a microcomputer, and the automatic adjusting heat dissipation system comprises a temperature sensor matched with a heat generating chip on the microcomputer, a uniform temperature radiator, a side air outlet fan, a lower half shell, an upper half shell and a control mainboard for automatically adjusting heat dissipation; the upper half shell is provided with the uniform temperature radiator, the side air outlet fan and the control mainboard; the side air outlet fan is electrically connected with the control mainboard; the temperature sensor is arranged on the uniform temperature radiator and connected with the control mainboard through a bus; the microcomputer is arranged between the upper half shell and the lower half shell, and the upper half shell and the lower half shell are fixed through fasteners; the upper half part of the uniform temperature radiator is in a funnel structure, and the lower half part is in a flat pipe bending structure; a cavity is arranged in the uniform temperature radiator, and a phase change working medium is filled in the cavity. Compared with the prior art, the application has the advantages of good heat dissipation performance, accurate temperature control and the like.

Description

Technical Field

[0001] This invention relates to the field of radiator design technology, and in particular to an automatic adjustment radiator and method. Background Technology

[0002] Currently, sensor-controlled automatic temperature control equipment is widely used in various fields. Such equipment typically includes a housing, sensor, controller, actuator, and execution device. The sensor is attached to the equipment being controlled, transmitting the obtained temperature data to the controller. The controller then sends commands to the actuator, which drives the execution device to operate.

[0003] Miniature computers like the Raspberry Pi, which need to balance performance and portability, are small in size and have densely packed chips, making them prone to heat dissipation issues. Prolonged operation can lead to increased temperature and CPU throttling. Therefore, there is an urgent need for a device that can effectively cool the Raspberry Pi while maintaining portability.

[0004] Patent application number CN201810392478.1 discloses a computer central processing unit heat dissipation device combining phase change material and liquid cooling. The lower part of the base has a water pump layer, and the middle part has a heat channel layer. The heat channel layer and the water pump layer are connected through a water pump port. The water pump layer is equipped with a water pump fan. A heat channel plate is installed on the heat channel layer. The heat channel layer has a V-shaped baffle and a heat channel layer base groove. One side of the V-shaped baffle has a coolant outlet and the other side has a coolant inlet. The heat channel plate is composed of dense heat sinks, a phase change material layer, and a thermally conductive metal plate. The dense heat sinks are fixed to the thermally conductive metal plate through the phase change material layer. The phase change material layer has a phase change material receiving cavity. The heat channel plate is sealed to the heat channel layer by a heat channel sealing rubber ring embedded in the heat channel layer base groove.

[0005] This solution uses a water-cooling system for heat dissipation. However, water-cooling has the drawback of not being able to achieve accurate temperature control and lacks a controller, meaning it operates continuously once powered on. Furthermore, water-cooling devices are relatively bulky and require an additional water supply, which fails to meet the portability requirements of microcomputers like the Raspberry Pi.

[0006] Existing temperature control devices for microcomputers such as Raspberry Pi have the following technical problems:

[0007] 1) Existing temperature control equipment generally adopts a binary temperature control algorithm, which only has two states: on or off. Its operation involves setting a pre-defined temperature threshold. When the temperature measured by the sensor exceeds this threshold, the controller controls the actuator to operate the device at maximum power until the sensor temperature drops below the threshold, at which point the controller stops the actuator. This process repeats cyclically. It can only operate when the temperature is above the threshold and stops when it is below, failing to achieve accurate temperature control. Furthermore, if the heat generated is only slightly above the threshold, the binary temperature control algorithm causes continuous on / off switching of the actuator, reducing its lifespan.

[0008] 2) Traditional temperature control devices for microcomputers such as Raspberry Pi use only a single sensor, which can only measure the temperature at one point and cannot reasonably estimate the temperature of the entire device. As a result, the measured temperature deviates significantly from the actual temperature, leading to unsatisfactory temperature control.

[0009] 3) Traditional temperature control devices for microcomputers like Raspberry Pi lack flexibility. Traditional temperature control devices for Raspberry Pi typically have pre-set programs, which cannot be manually adjusted once configured. If noise levels need to be reduced in a specific environment, such as by decreasing the actuator's output power, the traditional Raspberry Pi temperature control device would have to update the controller program to achieve the desired noise reduction. This constant updating of the controller program to adapt to different usage environments is cumbersome and inflexible. Summary of the Invention

[0010] The purpose of this invention is to overcome the defects of the prior art by providing an automatic adjustable radiator and its heat dissipation method.

[0011] The objective of this invention can be achieved through the following technical solutions:

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] 1) The aluminum-based integrated vapor chamber heat sink used in this invention employs vacuum cavity heat dissipation technology, enabling heat conduction in a two-dimensional plane, resulting in higher thermal conductivity and thus higher system heat dissipation efficiency. The lower half of the vapor chamber heat sink features a flat tube bending design, maximizing the contact area with the required heat dissipation chip without obstructing wiring. The upper half adopts a funnel-shaped design, with capillary channels inside the cavity to facilitate the condensation and reflux of the working fluid, enhancing the heat dissipation efficiency of the phase change working fluid. This invention's design can quickly cut off thermal shock and achieve excellent heat dissipation performance in a small volume.

[0014] 2) The automatic temperature control method provided by this invention employs an incremental PID temperature control algorithm to achieve automatic and precise temperature control of the temperature regulation system. This effectively solves the problem that the binary temperature control algorithm used in traditional temperature regulation systems cannot achieve precise temperature control and reduces the lifespan of the actuators. The automatic temperature control method used in this invention reduces the duration of full-load operation of the actuators, increases their lifespan, and has a small impact range in case of failure, without seriously affecting the operation process. When switching operating modes via buttons, the system experiences minimal impact and can achieve seamless switching.

[0015] 3) The heat dissipation method for automatic temperature adjustment provided by the present invention uses multiple temperature sensors to measure the temperature of different heat sources, and performs a weighted average algorithm on the obtained temperatures at each point to achieve a reasonable estimate of the equipment temperature.

[0016] 4) The heat dissipation method for automatic temperature adjustment provided by the present invention incorporates the function of button adjustment, which effectively solves the problem that once the program is set, it cannot be manually intervened, and thus realizes the function of selecting the temperature control mode by button.

[0017] 5) This invention installs the heat dissipation device inside the outer casing. The upper and lower casings provide mounting brackets for the entire system and also protect the Raspberry Pi 4B main body. This reduces the size of the device and increases its portability. Attached Figure Description

[0018] Figure 1 This is an exploded view of the automatic heat dissipation system of the present invention;

[0019] Figure 2 This is a top view of the automatic cooling system of the present invention;

[0020] Figure 3 This is a cross-sectional view of the automatic adjustment heat dissipation system AA of the present invention;

[0021] Figure 4 This is a front view of the automatic cooling system of the present invention;

[0022] Figure 5 This is a top view of the upper half of the automatic heat dissipation system of the present invention;

[0023] Figure 6 This is a right view of the upper half of the shell of the automatic heat dissipation system of the present invention;

[0024] Figure 7 This is a front view of the upper half of the shell of the automatic adjustment heat dissipation system of the present invention;

[0025] Figure 8 This is a top view of the upper half of the automatic heat dissipation system of the present invention;

[0026] Figure 9 This is a right view of the upper half of the shell of the automatic heat dissipation system of the present invention;

[0027] Figure 10 This is a front view of the upper half of the shell of the automatic adjustment heat dissipation system of the present invention;

[0028] Figure 11 This is a front view of the lower heat sink of the automatic heat dissipation system of the present invention;

[0029] Figure 12 This is a left view of the uniform temperature radiator of the automatic heat dissipation system of the present invention;

[0030] Figure 13 This is a cross-sectional view of the temperature-regulating radiator BB in the automatic cooling system of the present invention.

[0031] Figure 14 This is a perspective view of the temperature-equalizing radiator of the automatic heat dissipation system of the present invention.

[0032] Figure 15 This is an enlarged view of the heat sink on the heat exchanger of the automatic heat dissipation system of the present invention;

[0033] Figure 16 This is a flowchart of the automatic heat dissipation adjustment method of the present invention;

[0034] The numbers in the diagram are as follows:

[0035] 1. Temperature sensor, 2. Raspberry Pi 4B main body, 3. Heat sink, 4. Side-exhaust fan, 5. Lower heat sink, 6. Lower half shell, 7. Upper half shell, 8. Control motherboard. Detailed Implementation

[0036] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0037] This implementation mainly adopts active convection cooling combined with passive heat conduction cooling, and through the rational design of mechanical structure and control program, it achieves a good intelligent heat dissipation effect.

[0038] like Figure 1-4As shown, this invention provides an automatic cooling system. The hardware of the automatic cooling system includes a pair of DS18B20 temperature sensors 1, a Raspberry Pi 4B main body 2, an aluminum-based integrated heat sink 3, a side-exhaust fan 4, a lower heat sink 5, a lower half-shell 6, an upper half-shell 7, and a control motherboard 8. The DS18B20 temperature sensors 1 are TO-92 packaged or other surface mount packages and are attached to the aluminum-based integrated heat sink 3 using thermally conductive silicone grease. The aluminum-based integrated heat sink 3 is installed in a recess in the upper half-shell 7 and is attached using thermally conductive silicone. The control motherboard 8 is installed in a square opening in the upper half-shell 7 for easy access to buttons. The side-exhaust fan 4 is installed in the fan mounting position of the upper half-shell 7 and is connected by bolts. The lower heat sink 5 is fixed in a fixing slot in the lower half-shell 6. The two DS18B20 temperature sensors 1 are connected to the interface position of the control motherboard 8 using wires.

[0039] After the above components are installed, thermal grease, phase change thermal grease or other thermal conductive materials can be applied to the aluminum-based integrated heat sink 3 and the lower heat sink 5 at the positions where they contact the Raspberry Pi 4B body 2.

[0040] Finally, the upper shell 7, after all components have been installed, is joined to the lower shell 6 at the corresponding screw hole positions, and the bolts are tightened to complete the final assembly.

[0041] After final assembly, the entire heat dissipation system is enclosed by the upper shell 7 and the lower shell 6, forming a cuboid. The upper and lower shells provide a support for the heat dissipation system and also provide shell protection for the Raspberry Pi 4B main body 2.

[0042] like Figure 5-7 As shown, the upper shell 7 is designed with openings for the interfaces that the Raspberry Pi 4B main body 2 may need during use, and recesses are designed for installing heat dissipation devices. The upper shell 7 is generally rectangular, with a projected area similar to that of the Raspberry Pi 4B main body 2, and the screw hole positions are consistent to ensure portability after the device is installed as much as possible.

[0043] like Figure 8-10 As shown, the lower shell 6 is designed with square holes and snap-fit ​​for the lower heat sink 5 to be installed as needed, and foot pads are added to ensure airflow at the bottom of the device after installation.

[0044] like Figure 11 As shown, the lower heat sink 5 is made of aluminum and, after installation, conducts heat to the back of the Raspberry Pi 4B main body 2 for passive heat dissipation.

[0045] The lower shell 6 and the upper shell 7 can be made of materials such as polyethylene, polypropylene, ABS, PA, and polystyrene, and can be formed by injection molding or 3D printing.

[0046] like Figure 11-15 As shown, the lower half of the aluminum-based integrated vapor chamber heat sink is designed to be as small as possible to prevent obstructing the wiring of the Raspberry Pi 4B main body 2. The lower half of the aluminum-based integrated vapor chamber heat sink 3 adopts a flat tube bending design, maximizing the contact area with the required heat dissipation chip without increasing its volume. The upper half of the aluminum-based integrated vapor chamber heat sink 3 adopts a funnel shape design to accommodate the condensation and reflux of the working fluid. Heat sink fins are added to the top of the aluminum-based integrated vapor chamber heat sink 3 to accelerate condensation. In this embodiment, the aluminum-based integrated vapor chamber heat sink 3 uses an integrated design of heat sink fins and heat conduction cavity. The filling of the cavity working fluid in the aluminum-based integrated vapor chamber heat sink 3 can be completed by a one-time vacuuming, one-time filling with liquid phase change working fluid, and welding sealing, making the process relatively simple. It should be noted that the volume of liquid phase change working fluid to be filled should reach a certain level. Figure 12 The shaded area shown in the BB cross-section diagram.

[0047] In this embodiment, the enclosed cavity is under negative pressure. Therefore, the boiling point of the phase change working fluid is lowered under negative pressure, which facilitates rapid evaporation of the phase change working fluid upon heating and timely heat dissipation. It is understood that the phase change working fluid includes, but is not limited to, water, alcohol, propanol, etc.

[0048] The upper portion of the integrated aluminum-based heat sink 3 has airflow provided by the side-exhaust fan 4, enhancing the heat dissipation effect of the integrated aluminum-based heat sink 3. It should be noted that, as... Figure 3 As shown, the height of the heat sink fins on the integrated aluminum-based heat sink 3 is the same as the height of the side-exhaust fan 4, and the airflow generated by the side-exhaust fan 4 can flow into the gaps of the heat sink fins on the integrated aluminum-based heat sink 3. It should be noted that the side-exhaust fan used in this case is model GDB5010, but other side-exhaust fans that meet the heat dissipation requirements can also be selected.

[0049] The control motherboard contains a voltage regulator chip, a main control chip, a fan motor driver chip, and buttons. In this embodiment, the control motherboard 8 is powered by 10V DC, with an LM7805 voltage regulator chip stepping the input voltage down to 5V to power the controller and temperature sensors. The controller selected in this embodiment is an STC15W408AS chip, and the temperature sensor is a DS18B20, programmed in C language. The entire system uses a 1-ware (using a single signal line to transmit both clock and data, and the data transmission is bidirectional) single-bus communication protocol to acquire the values ​​from the dual temperature sensors DS18B20. The two temperature values ​​are then weighted and processed using a PID algorithm to calculate the PWM magnitude. It is important to note that the controller controls the fan motor speed through PWM. Finally, the PWM is transmitted to the fan motor driver chip via wires on the circuit board. In this embodiment, the fan motor driver uses a DRV8833 chip. The 10V power supply directly powers the full-bridge driver chip.

[0050] To achieve automatic temperature control, this invention also provides an intelligent heat dissipation algorithm for the intelligent heat dissipation hardware system. The intelligent heat dissipation algorithm includes a temperature weighted algorithm, a PID (proportional-integral-derivative) automatic temperature control algorithm, and a button adjustment algorithm.

[0051] A weighted algorithm is applied to the collected temperatures. This algorithm estimates the overall system temperature by averaging the measurements from the two temperature sensors. The specific calculation formula is as follows:

[0052]

[0053] TEMP is the estimated overall system temperature. temp1 and temp2 are the temperatures measured by the two temperature sensors respectively, and power1 and power2 are the weighting coefficients corresponding to temp1 and temp2 respectively. By appropriately selecting the weighting coefficients power1 and power2, a reasonable overall system temperature TEMP can be estimated using the above formula. Using a temperature weighting algorithm can effectively remove erroneous temperature values, enhancing the reliability of temperature control.

[0054] Furthermore, the system's PID automatic temperature control algorithm adopts an incremental PID algorithm. The specific C language program for the incremental PID algorithm is as follows:

[0055] err[0] = err[1];

[0056] err[1] = err[2];

[0057] err[2] = TEMP - TEMP_count;

[0058] PWM=(KP*(err[2]-err[1])+(KI*err[2]+KD*(err[2]-2*err[1]+err[0])));

[0059] The arrays err[0], err[1], and err[2] are used to store the temperature difference values ​​of the last three times. The value of err[2] is obtained by subtracting the set ideal temperature value TEMP_count from the estimated temperature value TEMP obtained in equation (1). KP, KI, and KD are the proportional coefficient, integral coefficient, and derivative coefficient, respectively. PWM (Multiple Pulse Width Modulation) is used to calculate the duty cycle transmitted to the driver chip.

[0060] The incremental PID temperature control algorithm is used because the control increment is determined only by the three most recent sampled values, making it easy to achieve good control through weighted processing. Therefore, if a system malfunctions, the impact is small and will not seriously affect the operation. Furthermore, the system experiences minimal impact when switching operating modes via buttons, allowing for seamless switching. The entire system's temperature is sampled every ten milliseconds, and the PID control is executed every five milliseconds.

[0061] like Figure 16 The system's operating procedure flowchart shows that the control system has three different operating modes, which can be adjusted by buttons according to user needs. The corresponding modes are as follows:

[0062] A powerful cooling mode that achieves maximum heat dissipation without considering noise;

[0063] Automatic mode that adjusts to temperature changes without considering noise;

[0064] A quiet mode with low noise and temperature-sensitive adjustment is required;

[0065] Furthermore, after the control system is turned on, the controller on the motherboard determines the working mode selected by the button. The default mode is automatic when the power is on. The controller collects the temperature of the two temperature sensors, performs a temperature weighting algorithm, and then sends the value calculated by the temperature weighting algorithm to the PID automatic temperature control algorithm to obtain the corresponding PWM signal. Finally, the signal is sent to the driver chip.

[0066] Furthermore, when the control system selects the quiet mode, the controller collects the temperatures from two temperature sensors, performs a temperature-weighted algorithm, and then sends the calculated value to the PID automatic temperature control algorithm to obtain the corresponding PWM signal. The controller then limits the amplitude of the calculated PWM signal, and sets the PWM signal to the quiet mode threshold if the duty cycle value exceeds the set threshold. This reduces the engine speed and thus decreases noise. The limited PWM signal is then sent to the driver chip.

[0067] Furthermore, when the control system selects the high-power cooling mode, the controller directly outputs 99% of the PWM signal and transmits it to the driver chip. The cooling fan is then driven at maximum power to achieve maximum cooling performance.

[0068] The control motherboard 8 has two buttons, P4 and P5. Button P4 is the mode selection button; each press of P4 selects the next working mode. Button P5 is the confirmation button; after selecting the desired working mode, pressing P5 will select the currently chosen working mode and operate in that mode. There is no need to shut down the machine during mode selection; hot-switching is possible. The specific operation procedure is as follows:

[0069] The system defaults to automatic mode upon power-up. Each press of button P4 selects the next mode, cycling through automatic, quiet, and high-performance cooling modes. To switch to quiet mode, press button P4, and the system will transition from automatic to quiet mode. Pressing button P5 then selects the current quiet mode and begins operation. The system will then execute the quiet mode's procedures.

[0070] When the system needs to adopt a high-performance cooling mode, the default initial mode is automatic. Press button P4 to switch to silent mode, press it again to switch to high-performance cooling mode, and then press button P5 to select the current high-performance cooling mode. The system will then execute the high-performance cooling mode procedure.

[0071] When the system needs to switch to automatic mode, and the current mode is strong cooling, press button P4 to switch to automatic mode, then press button P5 to select the current automatic mode. The system will then execute the automatic mode procedure.

[0072] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. An automatic cooling system for dissipating heat from a microcomputer, characterized in that, The automatic cooling system includes a temperature sensor (1) matched with the heat-generating chip on the microcomputer, a heat sink (3), a side-exit fan (4), a lower half shell (6), an upper half shell (7), and a control motherboard (8) for automatic cooling. The upper shell (7) is equipped with a heat exchanger (3), a side-exit fan (4), and a control motherboard (8); the side-exit fan (4) is electrically connected to the control motherboard (8); the temperature sensor (1) is installed on the heat exchanger (3) and connected to the control motherboard (8) via a bus; the microcomputer is located between the upper shell (7) and the lower shell (6), and the upper shell (7) and the lower shell (6) are fixed by fasteners; the temperature sensor (1) adopts a miniaturized package including surface mount packaging; the temperature sensor (1) is fixed to the heat exchanger (3) with thermal grease. The upper part of the uniform temperature radiator (3) is a funnel-shaped structure, and the lower part is a flat tube bending structure; the uniform temperature radiator (3) has a cavity inside, the cavity is filled with a phase change working fluid, the cavity of the radiator (3) is in a vacuum negative pressure state, and the inner wall of the cavity is provided with capillary channels. The top of the heat exchanger (3) is provided with an upper heat sink, and the height of the upper heat sink is the same as the height of the side-exit fan (4). The heat exchanger (3) and the lower heat sink (5) are coated with thermally conductive materials at the positions where they contact the microcomputer. The thermally conductive materials include thermally conductive silicone grease and phase change thermally conductive silicone grease.

2. The automatic heat dissipation system according to claim 1, characterized in that, The lower shell (6) is provided with openings, buckles and feet, and a lower heat sink (5) is fixed on the buckle.

3. The automatic heat dissipation system according to claim 1, characterized in that, The materials of the lower shell (6) and the upper shell (7) include polyethylene, polypropylene, ABS, PA and polystyrene. The lower shell (6) and the upper shell (7) are formed by injection molding or 3D printing. The lower shell (6) and the upper shell (7) are provided with corresponding screw holes and are fixed by bolts.

4. The automatic heat dissipation system according to claim 1, characterized in that, The hardware on the control motherboard (8) includes a control chip, a driver chip for driving the fan, and a button for switching modes.

5. A heat dissipation method for the automatic adjustment heat dissipation system according to any one of claims 1-4, characterized in that, When the heat dissipation system is operating in automatic mode, the heat dissipation method performs the following steps: The control chip reads the temperatures collected by multiple temperature sensors, and calculates the weighted average of the measurements from multiple temperature sensors to estimate the overall temperature of the system. An incremental PID algorithm is used to calculate the fan control PWM signal based on the estimated temperature; The PWM signal is transmitted to the driver chip to drive the fan to rotate.

6. The heat dissipation method according to claim 5, characterized in that, The heat dissipation system also includes a quiet mode and a high-heat dissipation mode. When the heat dissipation system is operating in quiet mode, the heat dissipation method performs the following steps: The control chip reads the temperatures collected by multiple temperature sensors, and calculates the average value of the measured values ​​from multiple temperature sensors to estimate the overall temperature of the system. An incremental PID algorithm is used to calculate the fan control PWM signal based on the estimated temperature; The calculated PWM signal is judged and limited. When the duty cycle of the PWM signal is greater than the set quiet mode threshold, the duty cycle of the PWM signal is made equal to the quiet mode threshold. The limited PWM signal is transmitted to the driver chip; When the heat dissipation system is operating in strong heat dissipation mode, the control chip directly outputs 99% of the PWM signal to the driver chip.

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