A thermal control system

Abstract

The present invention provides a thermal control system, which includes a loop heat pipe, a fin, a fan, a heating plate, a pump and a connecting hose. The evaporation end of the loop heat pipe is installed between the working parts, and the condensation end is embedded in the condensation plate. The liquid condensed by heat dissipation at the condensation end flows back to the evaporation end through the liquid pipeline; the fin and the fan are placed on the outside of the condensation plate for dissipating heat outward; the heating plate is thermally connected to the working part, and the connecting hose connects the heating plate and the condensation plate to form a second heat exchange system. The pump drives deionized water through the hose, flows through the heating plate and the condensation plate, and is recycled. In order to meet the insulation requirements of the working parts, the present invention separately sets a connecting hose channel parallel to the fluid inside the loop heat pipe, and plasma water flows in it. A set of water circulation heating system is designed for standby use to meet the working needs of the working parts under extremely cold conditions, and it can also play an auxiliary heat dissipation role.

Description

Technical Field

[0001] The invention relates to a heat pipe technology, in particular to a loop heat pipe of a tree-like structure condenser, belonging to the heat pipe field of F28d15 / 02. Background Art

[0002] Heat pipe technology is a heat transfer element called "heat pipe" invented by George Grover of Los Alamos National Laboratory in the United States in 1963. It makes full use of the principle of heat conduction and the rapid heat transfer properties of phase change media. It transfers the heat of the heating object to the outside of the heat source quickly through the heat pipe. Its thermal conductivity exceeds that of any known metal.

[0003] Heat pipe technology was previously widely used in aerospace, military and other industries. Since it was introduced into the radiator manufacturing industry, people have changed the design ideas of traditional radiators, getting rid of the single cooling mode that simply relies on high air volume motors to obtain better cooling effects. The use of heat pipe technology enables radiators to obtain satisfactory heat exchange effects, opening up a new world for the cooling industry. At present, heat pipes are widely used in various heat exchange equipment, including nuclear power and computer fields, such as the utilization of waste heat from nuclear power.

[0004] A loop heat pipe refers to a closed loop heat pipe. It is generally composed of an evaporator, a condenser, a liquid reservoir, and steam and liquid pipelines. Its working principle is: a heat load is applied to the evaporator, the working fluid evaporates on the outer surface of the evaporator capillary core, the generated steam flows out of the steam channel into the steam pipeline, and then enters the condenser to condense into liquid and supercool. The reflux liquid enters the liquid trunk through the liquid pipeline to replenish the evaporator capillary core, and the cycle continues in this way. The circulation of the working fluid is driven by the capillary pressure generated by the evaporator capillary core, and no external power is required. Since the condensing section and the evaporating section are separated, loop heat pipes are widely used in the comprehensive application of energy and the recovery of waste heat.

[0005] The condenser of the current loop heat pipe generally adopts a conventional tubular heat dissipation structure, which has the problem of low heat exchange efficiency. In view of the above defects, the present invention improves the current loop heat pipe and proposes a new condenser structure to improve the heat dissipation capacity of the loop heat pipe.

[0006] The loop heat pipe system has the problem of poor operating performance under extreme environments, so the present invention improves this problem. Summary of the invention

[0007] The invention provides a new loop heat pipe system to solve the technical problem of low heat exchange capacity of the heat dissipating loop heat pipe.

[0008] In order to achieve the above object, the technical solution of the present invention is as follows:

[0009] A thermal control system comprises a loop heat pipe, a fin, a fan, a heating plate, a pump and a connecting hose, wherein the evaporation end of the loop heat pipe is installed between working parts, and the condensation end is embedded in the condensation plate, and the liquid condensed by heat dissipation at the condensation end flows back to the evaporation end through a liquid pipeline; the fin and the fan are placed on the outside of the condensation plate for dissipating heat outwards; the heating plate is thermally connected to the working parts, and the connecting hose connects the heating plate and the condensation plate to form a second heat exchange system, and the pump drives deionized water to pass through the hose, flow through the heating plate and the condensation plate, and be recycled.

[0010] Preferably, the hose is connected to the heating plate and the condensing plate in the form of a coil for heat exchange with the heating plate and the condensing plate.

[0011] Preferably, the heating plate is connected to the temperature controller via a circuit; the temperature sensor is installed on the outside of the working component to detect the temperature of the working component.

[0012] Preferably, the condensation part of the second heat exchange system includes a condensing coil, a heat exchange component, a heat conductive copper sheet and a thermoelectric refrigerator. The condensing coil is thermally connected to the condensing plate, the cooling surface of the thermoelectric refrigerator is thermally connected to the upper surface of the heat exchange component, and a portion of the lower surface of the heat conductive copper sheet is thermally connected to the upper surface of the condensing coil.

[0013] Preferably, the heat exchange component is a liquid reservoir.

[0014] Preferably, the liquid reservoir is connected to the heating coil for replenishing water to the heating coil and performing TEC cooling and heating heat exchange with the heating coil.

[0015] Preferably, the second heat exchange system also includes a dual-way relay, a MOS tube and a DC power supply. The dual-way relay is connected to the TEC, the MOS tube is connected to the dual-way relay, and the DC power supply, the MOS tube, the dual-way relay and the TEC installed above the loop heat pipe reservoir are connected by wires to form a loop. The DC power supply is responsible for powering the thermoelectric cooler. The dual-way relay can change the power supply direction of the TEC by changing the state of the normally open interface and the normally closed interface, and the MOS tube can control the on and off of the loop.

[0016] Preferably, the single chip microcomputer is connected to the dual-circuit relay, MOS tube and a temperature sensor installed on the working part, and can receive temperature data of the working part and use it as a judgment factor to control the working state of the dual-circuit relay and MOS tube.

[0017] Preferably, when it is detected that the temperature of the working part is lower than the predetermined temperature, a reverse power supply mode is adopted. At this time, the pump is started, the single-chip microcomputer keeps the MOS tube in the on state, and switches the working state of the dual-circuit relay. At this time, the DC power supply reversely supplies power to the TEC, and the contact surface with the liquid reservoir is the cooling surface, and the contact surface with the thermal conductive copper sheet is the heating surface. The heating surface of the TEC transfers heat to the condensing coil of the condensing plate through the thermal conductive copper sheet, and then circulates to the evaporation plate coil to increase the temperature of the working part. In this working mode, the TEC circuit always remains on. The structure of the evaporator includes a microchannel evaporator (heat exchanger) located on the upper part of the temperature equalizing plate and thermally connected to the temperature equalizing plate, and the bottom of the temperature equalizing plate is thermally connected to the heat source. The temperature-averaging plate includes an upper plate and a lower plate, wherein a support column is arranged in the upper plate, and a micro-cylinder array is arranged in the lower plate, wherein the micro-cylinder array and the support column together constitute a liquid return column of the temperature-averaging plate, wherein the gap between the support columns arranged in the upper plate is larger than the gap between the micro-cylinders in the lower plate, and the diameter of the micro-cylinders and the spacing between the micro-cylinders are used to generate a capillary driving force, and the capillary force of the micro-cylinders corresponding to the lower part of the gap between the two support columns 11 gradually increases from one support column to another support column, and then gradually decreases. Through the above arrangement, the fluid can be further drawn into the gap by the capillary force, and the fluid can be evenly distributed at the bottom of the lower plate, thereby achieving balanced heat exchange.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1) In order to meet the insulation requirements of the working parts, the present invention separately sets up a connecting hose channel parallel to the fluid inside the loop heat pipe, in which plasma water flows, and designs a water circulation heating system as a backup to meet the working needs of the working parts under extremely cold conditions, and also can play an auxiliary heat dissipation role.

[0020] 2) The present invention provides a new loop heat pipe of a tree-like structure condenser, which solves the technical problem of low heat exchange capacity of the loop heat pipe, and can also reduce the flow resistance of the heat exchange pipe as a whole, increase the heat dissipation area, and improve the heat exchange efficiency as a whole. The present invention further improves the heat dissipation capacity and achieves balanced heat dissipation by optimizing the structure of the tree-like structure and the number of branches. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the loop heat pipe structure of the present invention.

[0022] Figure 2 It is a schematic diagram of the preferred condenser structure of the present invention.

[0023] Figure 3 It is a schematic diagram of a preferred loop heat pipe structure of the present invention.

[0024] Figure 4-1 It is a schematic diagram of the preferred thermal control system structure of the present invention.

[0025] Figure 4-2 It is a schematic diagram of the preferred thermal control system structure of the present invention.

[0026] Figure 5 It is a response curve diagram of the PID control system of the present invention.

[0027] Figure 6 It is the TEC layout diagram and energy cycle diagram. DETAILED DESCRIPTION

[0028] The specific implementation modes of the present invention are described in detail below with reference to the accompanying drawings.

[0029] In this article, unless otherwise specified, “ / ” represents division, and “×” and “*” represent multiplication.

[0030] A loop heat pipe, such as Figure 1 As shown, the loop heat pipe includes an evaporator 1, a condenser 2, a liquid pipeline 3 and a steam pipeline 4, and the evaporator 1 and the condenser 2 are connected through the liquid pipeline 3 and the steam pipeline 4. When the loop heat pipe is working, the liquid ammonia in the liquid storage chamber 5 enters the loop heat pipe evaporator 1 through the suction effect of the capillary force provided by the capillary wick 5, and absorbs heat in the evaporator 1. The liquid ammonia is heated and vaporized in the evaporator 1, enters the steam pipeline 4, and condenses and liquefies with the external low-temperature medium in the condenser 2, and becomes liquid ammonia again, and flows back to the liquid storage chamber 5 through the liquid pipeline 3. The entire working process does not require external energy, and energy-saving and efficient operation can be achieved through the suction and reflux effect of the capillary wick and the phase change of the working fluid.

[0031] As an improvement, Figure 2 As shown, the condenser 2 adopts a tree-like structure flow channel, the condenser inlet 21 and outlet 22 are the roots, and then branches are formed along the inlet and outlet toward the middle, and the branches continue to branch at a certain distance, and so on. The branches of the inlet and outlet are connected in the middle of the condenser, thereby forming a tree-like structure flow channel with the inlet and outlet as the roots.

[0032] The present invention provides a new loop heat pipe of a tree-structured condenser, which solves the technical problem of low heat exchange capacity of the loop heat pipe, and can also reduce the flow resistance of the heat exchange pipe as a whole, increase the heat dissipation area, and improve the heat exchange efficiency as a whole.

[0033] Preferably, the number of branches is 2-5.

[0034] Preferably, the number of branches gradually increases from the inlet 21 to the middle of the condenser. The purpose of gradually increasing the number of branches is mainly to enhance heat transfer on the one hand and to ensure uniform heat exchange on the other hand. Because as the fluid flows, the temperature of the fluid continues to decrease, and the external heat exchange capacity becomes lower and lower. By setting the number of branches to increase continuously, the fluid can be heat-exchanged uniformly as a whole, and the difference in external heat dissipation at different positions is reduced, thereby forming a uniform heat exchange situation as a whole, which is similar to countercurrent heat exchange, and the heat exchange efficiency can be improved as a whole.

[0035] As a preference, the number of branches gradually increases from the inlet to the middle of the condenser. By such an arrangement, the heat exchange efficiency can be further improved, and the overall external heat exchange capacity can be enhanced.

[0036] Preferably, the number of branches increases first and then gradually decreases from the middle of the condenser to the outlet. As the temperature of the fluid continues to decrease, in order to ensure uniform heat exchange on the whole fluid and reduce the difference in external heat dissipation at different positions, the number of branches should continue to increase, thereby increasing the heat exchange area. However, as the fluid flows, the fluid begins to gradually cool down and become liquid, and its volume is greatly reduced. Therefore, in order to ensure that the liquid on the pipeline fills the entire fluid pipeline, the number of branches is gradually reduced. Otherwise, some pipelines may have no fluid or very little fluid, resulting in a waste of area. Through the above arrangement, it is possible to reduce costs while meeting sufficient heat exchange.

[0037] As a preference, from the middle of the condenser to the outlet, the number of branches first increases in magnitude and then gradually decreases in magnitude. By such an arrangement, the heat exchange efficiency can be further improved, the overall external heat exchange capacity can be enhanced, and the cost can be further reduced.

[0038] As a preference, the flow channel size should not be too large or too small, otherwise it will increase the flow resistance, increase the manufacturing cost, and reduce the heat exchange efficiency. The best ratio of the flow channel size is as follows:

[0039]

[0040]

[0041] D is the hydraulic diameter of the flow channel, m; L is the flow channel length, m; n is the number of sub-flow channels at the bifurcation of each branch flow channel; the subscript i is the flow channel order of the parent flow channel at the bifurcation, and i+1 is the flow channel order of the sub-flow channel at the bifurcation.

[0042] Through the above-mentioned optimization design, the cost and flow resistance can be optimized while meeting the heat exchange requirements.

[0043] Preferably, D1 is 1.45-1.55 mm, preferably 1.5 mm, and L1 is 14-15 mm, preferably 14.4 mm.

[0044] As a preference, Figure 1 As shown, it also includes a liquid storage chamber 5. When the loop heat pipe is working, the liquid ammonia in the liquid storage chamber 5 enters the evaporator through the suction effect of the capillary force provided by the capillary wick.

[0045] Preferably, a capillary structure is further included, and the capillary structure is arranged in the liquid pipeline.

[0046] Preferably, the evaporation end of the loop heat pipe adopts a cylindrical design, the interfaces at both ends of the tube body are used to connect the steam pipeline and the liquid pipeline, and the liquid storage chamber is connected to the injection interface.

[0047] Preferably, the fluid in the loop heat pipe is ammonia.

[0048] Preferably, the capillary core blank is formed by sintering metal powder in a sintering furnace, and a corresponding pore-forming agent is added during the sintering process so that the metal powder forms a porous structure during the sintering process.

[0049] The structure of the evaporator 1 includes a microchannel evaporator (heat exchanger) located on the upper part of the uniform temperature plate and thermally connected to the uniform temperature plate, and the bottom of the uniform temperature plate is thermally connected to the heat source. The uniform temperature plate structure is the same as the prior application 2022102981251, and the uniform temperature plate structure and the entire structure of the microchannel heat exchanger are included in the present application. The uniform temperature plate includes an upper plate and a lower plate, a support column is arranged in the upper plate, and a micro-cylinder array is arranged in the lower plate. The micro-cylinder array and the support column together constitute the liquid return column of the uniform temperature plate, wherein the gap between the support columns arranged in the upper plate is larger than the gap between the micro-cylinders of the lower plate, and the diameter of the micro-cylinders and the spacing between the micro-cylinders are used to generate capillary driving force. The micro-cylinder array has a smaller diameter and spacing to increase the capillary driving force, in order to increase the power of the condensed liquid reflux in the uniform temperature plate and prevent the local high heat flux density from being evaporated locally instantly. In addition, the micro-cylinder structure can accelerate the introduction of heat into the interior of the uniform temperature plate, accelerate the evaporation phase change of the internal liquid working medium, and reduce the heat transfer thermal resistance.

[0050] Preferably, the capillary force of the micro-columns corresponding to the lower part of the gap between the two support columns 11 gradually increases from one support column to another, and then gradually decreases. Through the above arrangement, the fluid can be further sucked into the gap by the capillary force, and the fluid can be evenly distributed at the bottom of the lower plate, thereby achieving balanced heat exchange.

[0051] Preferably, the capillary force first gradually increases with increasing amplitude, and then gradually decreases with increasing amplitude. The above arrangement can further improve the uniformity.

[0052] Preferably, the critical point from gradually increasing to gradually decreasing is the middle of the gap, that is, the capillary force first gradually increases from one support column to the middle of the gap, and then gradually decreases from the middle of the gap to the other support column.

[0053] Preferably, as the gap distance increases, the difference between the capillary force of the micro-cylinder corresponding to the lower part of the gap and the capillary force corresponding to the lower part of the support column becomes larger and larger. By setting it in this way, the heat exchange can be more balanced and uneven heat exchange can be avoided.

[0054] Preferably, the diameter of the micro-cylinder is 5-10 μm, the spacing between the centers of adjacent micro-cylinders is 10-20 μm, and the height is 25-50 μm.

[0055] Preferably, the support pillars are square, with a side length of 15-30 μm and a height of 30-60 μm, and the spacing between adjacent sides of adjacent support pillars is 15-30 μm.

[0056] The microchannel evaporator is not limited to the shape of the microchannel heat exchanger of the prior application 2022102981251, and the temperature equalizing plate is not limited to the shape of the prior application 2022102981251. It can be set to an arc shape as needed to meet the wall shape requirements.

[0057] The present invention also provides a thermal control system, as shown in FIG4. The system includes a loop heat pipe, a fin 13, a fan 14, a heating plate 17, a pump 15, and a connecting hose 16. The evaporation end 1 of the loop heat pipe is installed between the working parts, and the condensation end 2 is embedded in the condensation plate. The liquid condensed by heat dissipation flows back to the evaporation end 1 through the liquid pipeline 3; the fin 13 and the fan 14 are placed on the outside of the condensation plate for dissipating heat outward; the heating plate 17 is installed on the outside of the working part. Preferably, the heating plate 17 is connected to the thermostat through a line; the temperature sensor is installed on the outside of the working part and connected to the single-chip microcomputer (preferably a TC264 dual-core microprocessor) through a line; the connecting hose passes through the heating plate and the condensation plate, and the heating plate is thermally connected to the working part. The pump drives the deionized water through the hose, flows through the heating plate and the condensation plate, and is recycled to solve the problem of the weakening of the phase change cooling effect due to excessive system resistance; and the pump work is small, which can improve the system COP value. The connecting hose connects the heating plate and the condensation plate to form a second heat exchange system. Preferably, the hose is connected to the heating plate and the condensing plate in the form of a coil for heat exchange with the heating plate and the condensing plate.

[0058] The optimal loop heat pipe is Figure 1-2 Loop heat pipe shown.

[0059] Normally, the evaporation end of the loop heat pipe absorbs the heat of the working parts, and then dissipates the heat through the condensation end. In order to meet the insulation requirements of the working parts, the present invention separately sets a connecting hose channel parallel to the fluid inside the loop heat pipe, in which plasma water flows, and designs a water circulation heating system for standby, in order to meet the working requirements of the working parts under extremely cold conditions, and also can play an auxiliary heat dissipation role.

[0060] The cold end of the TEC is fitted to the condenser plate to maintain the operating temperature of the condenser below the boiling point of the working fluid in the heat pipe. When the external ambient temperature is too high, the working fluid can be condensed and refluxed normally, cooling the capillary wick at the evaporation end, maintaining the working fluid in the buffer zone of the evaporation chamber in a two-phase flow state, and thus maintaining the uniform temperature of the working parts.

[0061] Under heating conditions, the electromagnetic reversing valve redirects the condensed water in the connecting hose 16 connected to the condenser to the insulation circuit. After being heated by the TEC, the condensed water flows through the heating coil thermally connected to the heating plate. The heating plate is installed on the wall of the working part, and dissipates heat to the working part by heat convection and heat radiation, providing a heat source for the working part.

[0062] like Figure 6 As shown, the condensing part of the second heat exchange system includes a condensing coil, a heat exchange component (preferably a liquid storage device), a heat conductive copper sheet, and a thermoelectric cooler (TEC), wherein the cooling surface of the thermoelectric cooler is thermally connected to the upper surface of the heat exchange component, and a portion of the lower surface of the heat conductive copper sheet is thermally connected to the upper surface of the condensing coil. Another portion of the lower surface of the heat conductive copper sheet is thermally connected to the upper surface of the thermoelectric cooler.

[0063] The present invention applies a thermoelectric cooler to a heat pipe temperature control system, which has a small size, small mass, no moving parts, high reliability, no pollution, rapid cooling and high temperature control accuracy, effectively forming a temperature difference between the evaporation end and the condensation end, ensuring the normal startup and stable operation of the loop heat pipe, and maintaining temperature stability when the thermal power fluctuates.

[0064] Preferably, the heat exchange component is a liquid reservoir, and preferably, the liquid reservoir is connected to the heating coil. It is used to add water to the heating coil and perform TEC cooling and heating heat exchange with the heating coil. The liquid reservoir does not participate in the circulation of the connecting hose heat exchange system. Preferably, a valve is set between the liquid reservoir and the heating coil.

[0065] Preferably, in the TEC auxiliary system, the hose heat exchange system also includes a dual-way relay, a MOS tube and a DC power supply. The dual-way relay is connected to the TEC, the MOS tube is connected to the dual-way relay, and the DC power supply, the MOS tube, the dual-way relay and the TEC installed above the loop heat pipe reservoir are connected by wires to form a loop. The DC power supply is responsible for powering the thermoelectric cooler. The dual-way relay can change the power supply direction of the TEC by changing the state of the normally open interface and the normally closed interface, and the MOS tube can control the on and off of the loop.

[0066] The present invention changes the power supply direction of the TEC by arranging a dual-path relay to change the states of the normally open interface and the normally closed interface, and the MOS tube can control the on and off of the loop, thereby realizing intelligent control of the TEC.

[0067] Preferably, the single chip microcomputer (controller) is connected to the dual-circuit relay, MOS tube and a temperature sensor installed on the working part, and can receive the temperature data of the working part and use it as a judgment factor to control the working state of the dual-circuit relay and MOS tube.

[0068] When the temperature of the working part is detected to be lower than the preset temperature, the reverse power supply mode is adopted. At this time, the pump starts, the single-chip computer keeps the MOS tube in the on state, and switches the dual-circuit relay working state. At this time, the DC power supply reversely supplies power to the TEC (that is, the contact surface with the liquid reservoir is the cooling surface, and the contact surface with the thermal conductive copper sheet is the heating surface). The heating surface of the TEC transfers heat to the condensing coil of the condensing plate through the thermal conductive copper sheet, and then circulates to the evaporating plate coil to increase the temperature of the working part. In this working mode, the TEC circuit always remains on.

[0069] The overall operation process of each component in the system is described as follows: When the temperature sensor detects that the temperature of the working component is higher than the rated maximum temperature, the TC264 dual-core microprocessor receives the temperature signal, combines the PID algorithm to control the fan speed, adjusts the direction and size of the voltage at both ends of the TEC, and at the same time, the heating coil absorbs the heat on the surface of the working component. The liquid working medium enters the heating coil through the action of the pump 15, vaporizes when the working component of the heating coil generates heat, and liquefies by heat exchange with the external low-temperature medium on the condensing plate (preferably, the condensing plate is provided with a condensing coil, and through the condensing coil), returns to the liquid storage chamber through the hose. The cooling power of the above process can be closed-loop controlled by PWM (Pulse Width Modulation). When insulation is required, a reverse voltage is applied to the TEC. At this time, the cold end and the hot end of the TEC are swapped, and the fluid in the original fluid cooling cycle is heated and passed through the electric insulation circuit. The same as the refrigeration principle, the heating process can also achieve the same closed-loop control. Under heating conditions, the condensing plate coil is heated by the TEC and flows through the heating plate installed on the outside of the working part, dissipating heat to the working part by heat convection and heat radiation, thereby increasing the temperature of the working part.

[0070] The present invention is provided with a connecting hose channel, in which plasma water flows, which can assist in supplementing the heat exchange needs of the loop heat pipe on the one hand, and can heat the heating plate on the other hand to meet the working needs of the working parts under extremely cold conditions.

[0071] Preferably, the present invention also automatically controls the operation of the second heat exchange system according to the temperature of the working component detected by the temperature sensor.

[0072] When the temperature detected by the temperature sensor exceeds the preset data, the controller controls the pump 15 to start, the heating coil absorbs the heat from the surface of the working part, the liquid working medium enters the heating coil through the action of the pump 15, vaporizes at the working heat generated by the working part of the heating coil, exchanges heat with the external low-temperature medium at the condensing plate (preferably, the condensing plate is provided with a condensing coil, and through the condensing coil), liquefies, and flows back to the liquid storage chamber through the hose. The above arrangement can supplement the insufficient heat exchange capacity of the heat exchange tube and accelerate the heat dissipation of the working part.

[0073] Preferably, as the detected temperature rises, the power of the pump is gradually increased.

[0074] As a preferred embodiment, as the detected temperature rises, the power of the pump gradually increases in a larger and larger range. By continuously increasing the power of the pump and the increase in the range, the heat is promptly and quickly dissipated to ensure the stable operation of the working parts.

[0075] Preferably, when the detected temperature is lower than the predetermined data, the controller controls the pump 15 to start, and the controller controls the reverse voltage to be applied to the TEC. At this time, the pump starts, the single-chip computer keeps the MOS tube in the on state, and switches the working state of the dual-circuit relay. At this time, the DC power supply reversely supplies power to the TEC (that is, the contact surface with the liquid reservoir is the cooling surface, and the contact surface with the thermal conductive copper sheet is the heating surface). The heating surface of the TEC transfers heat to the condensing coil of the condensing plate through the thermal conductive copper sheet, and then circulates to the evaporating plate coil to increase the temperature of the working parts. In this working mode, the TEC circuit always remains on.

[0076] Preferably, when the detected external ambient temperature is higher than the predetermined data, the controller controls the dual-circuit relay to keep the TEC in a forward power supply state (i.e., the contact surface with the liquid reservoir is a heating surface, and the contact surface with the heat-conducting copper sheet is a cooling surface), while the MOS tube remains in a conducting state under the control of the single-chip microcomputer. In this working mode, the TEC loop always remains in a conducting state, and constant power auxiliary cooling of the loop heat pipe can be achieved by adjusting the parameters of the DC power supply.

[0077] Preferably, a full-bridge circuit is used to control the TEC device, the bridge circuit is composed of four enhanced N-channel field effect transistors (TPH1R401NL) and is controlled by a full-bridge driver (drv8701e).

[0078] When the detected temperature is lower than the set value, the controller controls the pump 15 to start, outputs periodic pulses of the bridge circuit working in the forward direction to the full-bridge driver, and controls the two MOS tubes of the TEC heating circuit to turn on, and the two MOS tubes of the cooling circuit to turn off. By adjusting the duty cycle of the pulse signal, the on-time of the MOS tube is adjusted, and the filtering effect of the energy storage element is used to output a relatively stable current for the TEC to work. In auxiliary cooling, the MOS tube of the other side of the circuit is turned on, and the adjustment method is the same as the heating state. The current sampling device (INA282) is used to collect the working current of the TEC, calculate the heating power, and return it to the controller together with the temperature signal as a feedback signal to realize the closed-loop control of the TEC regulator, and switch the working power and heating and cooling states.

[0079] The cold end of the TEC is fitted to the condenser plate to maintain the operating temperature of the condenser below the boiling point of the working fluid in the heat pipe. When the external ambient temperature is too high, it ensures that the working fluid can condense and reflux normally, cools the capillary wick at the evaporation end, maintains the working fluid in the evaporator buffer in a two-phase flow state, and thus maintains the temperature of the working parts.

[0080] Preferably, the working component is a battery pack, preferably a cylindrical lithium battery cell, and preferably a new energy vehicle battery pack.

[0081] From the calculation of wind speed, it can be seen that air volume is a complex relationship determined by multiple variables, which needs to be fitted by PID algorithm. There is no strong coupling relationship between cooling air volume and heating or cooling power. Therefore, the two control quantities are processed as two systems for separate control. The feedback line of wind speed control is composed of flow meter. Wind speed control is a cascade semi-closed loop control, and the controlled object is the system temperature. When the ambient temperature meets the thermal control requirements and natural convection heat dissipation is used, the fan does not start. When the heat pipe power is insufficient and air-cooled convection heat exchange is required, the fan control system consists of two control closed loops: wind speed loop and temperature loop. When the system temperature deviates, the temperature deviation is input into the temperature loop, and the temperature loop outputs the corresponding air volume expectation, which is subtracted from the current air volume returned by the flow meter to obtain the corresponding fan speed signal, which is applied to the fan through the electric regulator for speed adjustment. When the ambient temperature does not meet the thermal control requirements, if the ambient temperature is too low, TEC is heated, and the fan does not run at this time. The TEC heating power is used as the output, and the system temperature is the controlled object for closed-loop control. When the ambient temperature is too high and the TEC is cooling, the TEC and the fan operate separately. Through experiments, data on the coupling relationship between the fan and TEC output power of multiple groups are collected, and the operation of the two is controlled according to different proportions. The new control formula obtained by the present invention through a large number of optimizations is as follows:

[0082]

[0083] e(t) is used as the input of PID control, and u(t) is used as the output of PID controller and the input of the controlled object.

[0084] Kp——Proportional coefficient of the controller.

[0085] Ti——integral time constant of the controller.

[0086] Td——differential time constant of the controller.

[0087] Kp*e(t)——The role of the proportional link is to respond to the deviation instantly and reflect the deviation signal of the control system in a timely and proportional manner. Once the deviation occurs, the controller immediately takes control action to reduce the deviation.

[0088] ——Although the regulating effect of the integral link can eliminate the static error, it will also reduce the response speed of the system and increase the overshoot of the system.

[0089] ——The role of the differential link is to prevent the change of the deviation. It is controlled according to the change trend (speed of change) of the deviation. The faster the deviation changes, the greater the output of the differential controller, and it can be corrected before the deviation value becomes larger. The introduction of the differential action will help reduce the overshoot, overcome oscillation, and make the system stable. It is especially beneficial for high-order systems, and it speeds up the tracking speed of the system.

[0090] Discretize the PID control algorithm formula (Formula 1-1). The discretized PID formula is as follows:

[0091]

[0092] in:

[0093] k——sampling number, k=0, 1, 2, ...;

[0094] u k ——Computer output value at the sampling moment;

[0095] e k ——deviation value input at the sub-sampling time;

[0096] e k-1 ——The deviation value input at the k-1th sampling time;

[0097] Ki——integral coefficient,

[0098] Kd——differential coefficient, This control method adopts the ideal PID control law. It introduces integration on the basis of proportion to eliminate the residual error, and then adds differential action to improve the stability of the system. It is used for closed-loop temperature control to achieve fast response and precise convergence of temperature control effects.

[0099] After repeated debugging, the time domain transient response curve of the control system continues to converge to the control target, and can quickly reach the desired value and converge while allowing a certain amount of overshoot. Position is the relationship between the response curve of the PID control system and the change of parameters. Figure 5 shown.

[0100] The innovations of the present invention are as follows:

[0101] 1) Innovative design of the heat dissipation system structure. The system uses working parts as unit modules, which improves the heat dissipation efficiency of heat pipes while increasing the utilization rate of heat dissipation space; at the same time, it combines high-performance fins, fans and TEC, supplemented by liquid cooling and air cooling, effectively improving the working efficiency of the entire system.

[0102] 2) The evaporation end array is filled in the gap between cylindrical battery cells. In terms of the arrangement of the evaporation end of the loop heat pipe, the evaporation end is filled in the gap between the cylindrical working parts in the form of an array, which improves the utilization rate of the heat dissipation space, effectively solves the temperature rise and temperature difference problems under high power rate and high power discharge conditions, improves the system energy density, simplifies the system complexity, and can ensure dynamic heat dissipation and stable heat transfer, achieving precise heat dissipation while extending its cycle life.

[0103] 3) Innovative design and application of loop heat pipes. Loop heat pipes have high heat exchange efficiency, stable and reliable working process, and energy-saving and efficient. Compared with heat spreaders with the same principle and the same function, the application of loop heat pipes on working parts effectively reduces their heat dissipation costs. In addition, through the innovative design of the layout structure of the loop heat pipe, the processing cost of the heat pipe is reduced, and the efficient use of the heat dissipation space and the balance of the heat pipe power are achieved.

[0104] Although the present invention has been disclosed as above with preferred embodiments, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, so the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A thermal control system, the system comprising a loop heat pipe, a fin, a fan, a heating plate, a pump and a connecting hose, the evaporation end of the loop heat pipe is installed between the working parts, the condensation end is embedded in the condensation plate, the liquid condensed by heat dissipation at the condensation end flows back to the evaporation end through the liquid pipeline; the fin and the fan are placed on the outside of the condensation plate for dissipating heat outward; the heating plate is thermally connected to the working part, the connecting hose connects the heating plate and the condensation plate to form a second heat exchange system, the pump drives deionized water through the hose, flows through the heating plate and the condensation plate, and is recycled; the condensation part of the second heat exchange system comprises a condensation coil, a heat exchange component, a heat conductive copper sheet and a TEC, the condensation coil is thermally connected to the condensation plate, the cooling surface of the TEC is thermally connected to the upper surface of the heat exchange component, and a part of the lower surface of the heat conductive copper sheet is thermally connected to the upper surface of the condensation coil; the heat exchange component is a liquid storage tank; the second heat exchange system also comprises a two-way relay, a MOS tube and a DC power supply, the two-way relay is connected to the TEC, the MOS tube is connected to the two-way relay, the DC power supply, the MOS tube, the two-way relay are connected to the TEC, the MOS tube is connected to the two-way relay, and the DC power supply, the MOS tube, the two-way relay and the TEC are connected to the condensation plate. The TEC installed above the loop heat pipe reservoir is connected by wires to form a loop, the DC power supply is responsible for powering the TEC, the dual-channel relay can change the power supply direction of the TEC by changing the states of the normally open interface and the normally closed interface, and the MOS tube can control the on and off of the loop; the single-chip microcomputer is connected to the dual-channel relay, the MOS tube and the temperature sensor installed on the working part, and can receive the temperature data of the working part, and use it as a judgment factor to control the working state of the dual-channel relay and the MOS tube; when it is detected that the temperature of the working part is lower than the predetermined temperature, the reverse power supply mode is adopted, at this time the pump is started, the single-chip microcomputer keeps the MOS tube in the on state, and switches the working state of the dual-channel relay, at this time the DC power supply reversely powers the TEC, the contact surface with the reservoir is the cooling surface, and the contact surface with the thermal conductive copper sheet is the heating surface, the heating surface of the TEC transfers heat to the condensing coil of the condensing plate through the thermal conductive copper sheet, and then circulates to the heating plate coil to increase the temperature of the working part; in this working mode, the TEC loop is always turned on.

2. The thermal control system according to claim 1, characterized in that: The hose is connected to the heating plate and the condensing plate in the form of a coil for exchanging heat with the heating plate and the condensing plate.

3. The thermal control system according to claim 1, characterized in that: The temperature sensor is installed on the outside of the working part and is used to detect the temperature of the working part.

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