A discrete series low-distributed-capacitance liquid cooling heat dissipation device and method

Abstract

The application discloses a kind of discrete series low distributed capacitance liquid cooling heat dissipation device and method, it belongs to electronic device heat dissipation technical field, heat dissipation device includes several heat dissipation units, the top of each heat dissipation unit is used to set power device, and two adjacent heat dissipation units are connected by cooling liquid pipeline;Each heat dissipation unit includes matrix and radiator, cooling liquid pipeline is through the inside of matrix, the top center of matrix is equipped with mounting hole, and mounting hole is equipped with radiator, and the lower half of radiator is inserted into the inside flow channel of cooling liquid pipeline, and the top of radiator is used to place power device.The application adopts discrete series heat dissipation unit structure, cooling liquid pipeline is through each unit matrix, and the lower half of radiator is inserted into the inside flow channel of pipeline, and each unit independently corresponds a power device.Solve the parasitic distributed capacitance problem caused by shared metal radiator, eliminate resonance loop, inhibit switching oscillation, reduce loss, ensure that heat dissipation is uniform and dynamic equalization, improve the stability and service life of high-voltage series module.

Description

Technical Field

[0001] This invention belongs to the field of liquid cooling technology, and particularly relates to a liquid cooling device and method for discrete series low-distribution capacitors. Background Technology

[0002] When multiple power devices are connected in series to increase voltage, the devices are heat-dissipated and mounted on the same heat sink, forming distributed capacitance. The distributed capacitance and parasitic inductance are prone to oscillation when the power devices are switching, resulting in switching rise and fall delays, switching losses, and uneven dynamic voltage of the devices.

[0003] The existing conventional assembly method is as follows: all series power devices are uniformly mounted on the surface of the same integral metal heat sink, and an insulating pad is installed between the device and the metal heat sink to achieve electrical isolation.

[0004] The existing structure has the following defects: 1. Large parasitic distributed capacitance: All power devices share the same metal heat sink, resulting in a large area of ​​distributed capacitance between the device electrodes, the housing, and the common metal heat sink; 2. Switching oscillation problem: Distributed capacitance combined with parasitic inductance in the circuit can easily cause voltage and current resonance oscillations when power devices switch at high frequencies; 3. Deterioration of switching performance: Oscillation will cause delays in the rising and falling edges of the device switching, significantly increasing switching losses and reducing equipment efficiency; 4. Dynamic voltage equalization failure: Uneven dynamic voltage distribution of series power devices, local overvoltage of devices, seriously affects the working stability and service life of series modules, and may even cause device breakdown and damage.

[0005] In summary, the existing heat dissipation structure of shared metal heat sinks cannot meet the requirements for high-frequency and reliable operation of high-voltage series power devices. Summary of the Invention

[0006] Based on the technical problems existing in the prior art, the present invention provides a liquid cooling heat dissipation device and method for discrete series low-distribution capacitors.

[0007] According to a first aspect of the technical solution of the present invention, a discrete series-connected liquid cooling heat dissipation device with low distributed capacitance is provided. This device comprises a plurality of heat dissipation units connected in series, each of which has a power device mounted on its upper surface. Adjacent heat dissipation units are connected by a coolant pipe. Each heat dissipation unit includes a base and a radiator. The coolant pipe penetrates the interior of the base. A mounting hole is provided at the center of the top of the base, and a radiator is installed within the mounting hole. The lower half of the radiator extends into the internal flow channel of the coolant pipe, and the top of the radiator is used to place the power device.

[0008] A further improvement of the present invention is that: the radiator includes an immersion section and a heat-conducting section, the heat-conducting section is a plate-shaped platform, the immersion section includes a plurality of heat dissipation fins, the top of the immersion section is fixedly connected to the bottom of the heat-conducting section, and the immersion section is in contact with the coolant in the coolant pipe.

[0009] A further improvement of the present invention is that the coolant pipe includes a first section, a second section and a third section arranged in sequence, wherein the outer diameter of the first section and the third section is smaller than the outer diameter of the second section.

[0010] A further improvement of the present invention is that both the substrate and the heat sink are made of metal materials.

[0011] A further improvement of the present invention is that the substrate is made of a metal material and the heat sink is made of a ceramic material.

[0012] A further improvement of the present invention is that the substrate is made of an insulating material and the heat sink is made of a metal material.

[0013] A further improvement of the present invention is that both the substrate and the heat sink are made of ceramic material.

[0014] A further improvement of the present invention is that the coolant pipe is made of insulating material.

[0015] A further improvement of the present invention is that a sealing groove is provided on the inner sidewall of the mounting hole, and a sealing ring is provided in the sealing groove.

[0016] According to a second aspect of the technical solution of the present invention, a liquid cooling heat dissipation method for discrete series low-distribution capacitors is provided, and based on the above-mentioned liquid cooling heat dissipation device for discrete series low-distribution capacitors, the method is characterized by comprising the following steps: Step S1: Prepare several substrates, with coolant pipes running through the interior of each substrate, and pre-drill mounting holes at the center of the top of each substrate; Step S2: Fix a radiator in each of the mounting holes so that the lower half of the radiator extends into the internal flow channel of the coolant pipe; Step S3: Seal and connect two adjacent substrates through coolant pipes, so that the coolant pipes in all substrates are connected in sequence to form an overall cooling circuit, which constitutes several discrete series heat dissipation units. Step S4: Fill the connected overall cooling circuit with coolant so that the coolant fills all the internal flow channels of the coolant pipes; Step S5: Place the multiple power devices connected in series on top of the heat sink in each heat dissipation unit; Step S6: Drive the coolant to circulate within the overall cooling circuit. The heat generated by the power devices is transferred to the coolant in the coolant pipes through the radiator, and the circulating coolant carries the heat away.

[0017] Compared with the prior art, the above-mentioned technical solution of the present invention has the following beneficial technical effects: 1. This invention employs a structure of several discrete, series-connected heat dissipation units. Coolant pipes penetrate the base of each heat dissipation unit, with the lower half of the heat sink directly extending into the internal flow channel of the coolant pipes. This allows each heat dissipation unit to independently correspond to a power device. This achieves independent, separate heat dissipation in scenarios involving multiple power devices connected in series, solving the problem of large-area parasitic distributed capacitance caused by traditional multi-power devices sharing a single metal heat sink. It eliminates the resonant circuit formed by distributed capacitance and parasitic inductance at its source, effectively suppressing voltage and current oscillations during power device switching, reducing switching losses, and ensuring consistent heat dissipation conditions for each series-connected power device. This achieves dynamic, uniform voltage distribution and prevents damage from overvoltage on individual devices.

[0018] 2. This invention employs a split-type heat sink structure consisting of an immersion section and a heat-conducting section. By incorporating several heat sink fins in the immersion section, the immersion section directly contacts the coolant for heat exchange, while the heat-conducting section carries the power devices. This achieves highly efficient heat conduction and enhanced heat transfer, solving the problems of limited heat exchange area and low heat transfer efficiency in traditional smooth cylindrical immersion structures. The heat sink fins significantly increase the contact area between the heat sink and the coolant, enhancing convective heat transfer and significantly improving the heat transfer coefficient. The integrated two-section structure eliminates the contact thermal resistance of segmented connections, ensuring rapid heat transfer from the power devices to the coolant, further improving overall heat dissipation efficiency.

[0019] 3. This invention employs a three-section variable-diameter coolant pipe structure, by setting a middle second section with a larger outer diameter and two end first and third sections with smaller outer diameters. This achieves optimized coolant flow field distribution and solves the problems of high flow resistance, significant eddy current losses, and uneven heat exchange among heat dissipation units in traditional constant-diameter pipes. The middle large-diameter section reduces the coolant flow velocity, prolongs the contact time between the coolant and the radiator immersion section, and improves overall heat exchange efficiency; the end small-diameter sections smoothly transition the flow velocity change, reduce inlet and outlet flow resistance and energy loss, reduce the power consumption of the circulating pump, and ensure uniform heat exchange among all heat dissipation units.

[0020] 4. This invention uses metallic materials to fabricate both the substrate and the heat sink, giving both high thermal conductivity and excellent structural strength. This achieves efficient heat dissipation and stable load-bearing in high-power scenarios, solving the problem of insufficient thermal conductivity in insulating materials, which cannot meet the heat dissipation requirements of ultra-high-power devices. The high thermal conductivity of metallic materials allows for rapid conduction of heat generated by power devices to the coolant with minimal thermal resistance; simultaneously, the metallic substrate possesses higher structural strength and resistance to deformation, can withstand greater assembly stress and operating loads, and is easier to process and form, facilitating mass production and precision assembly.

[0021] 5. This invention uses a metallic material to prepare the substrate and a ceramic material to prepare the heat sink, balancing structural load-bearing capacity and electrical insulation performance. It achieves a balance between structural strength and insulation performance, solving the problems of large parasitic capacitance in all-metal structures and insufficient mechanical strength in all-ceramic structures. The metallic substrate possesses excellent structural rigidity and installation adaptability, providing stable installation support for pipes and heat sinks; the ceramic heat sink has good thermal conductivity and excellent insulation characteristics, which can block the electrical coupling path between power devices and cooling circuits, effectively reducing parasitic distributed capacitance and improving electrical safety performance under high-voltage conditions.

[0022] 6. This invention uses an insulating material to prepare the substrate and a metal material to prepare the heat sink, achieving physical and electrical isolation between each heat sink unit at the substrate level. This achieves a balance between heat dissipation performance and electrical isolation performance, solving the problems of electrical coupling and excessive parasitic capacitance caused by the metal substrate. The insulating substrate can completely isolate the electrical connection path between independent heat sinks, significantly reducing the parasitic capacitance between series units and effectively suppressing switching oscillations; the metal heat sink has a high thermal conductivity, ensuring the heat dissipation requirements of high-power devices, and significantly improving the electrical stability of the high-voltage series module while maintaining efficient heat dissipation capabilities.

[0023] 7. This invention uses ceramic materials to fabricate the substrate and heat sink, constructing a fully insulated heat dissipation unit structure. This achieves ultimate electrical isolation, solving the problems of electrical coupling paths and difficulty in further reducing parasitic capacitance in structures containing metal components. Ceramic materials possess both excellent thermal conductivity and superior insulation properties. The all-ceramic structure completely blocks electrical coupling between heat dissipation units and between power devices and the cooling system, reducing parasitic distributed capacitance to extremely low levels. It can withstand higher voltage stresses, and is particularly suitable for high-voltage power device series modules, significantly improving the insulation safety level and operational reliability of the device.

[0024] 8. In this invention, where the substrate is made of metal, the coolant channels are fabricated using insulating materials. This achieves electrical isolation between adjacent metal substrates, solving the problem of electrical connection between the metal substrates through the coolant channels, which would disrupt the electrical independence of each heat dissipation unit. The insulated coolant channels block the conductive path between adjacent metal substrates, preventing electrical coupling between heat dissipation units through the cooling circuit. This maintains the discrete insulation characteristics of each heat dissipation unit, ensuring that parasitic distributed capacitance remains at a low level. While preserving the structural strength advantages of the metal substrate, it also meets the insulation performance requirements of high-voltage series operation.

[0025] 9. This invention achieves a reliable static seal in the cooling channel by creating a sealing groove on the inner wall of the mounting hole and installing a sealing ring. This solves the common problem of coolant leakage in liquid cooling devices. The sealing ring, through elastic deformation, fills the tiny gap between the radiator and the mounting hole, achieving a self-tightening seal under coolant pressure. This effectively prevents coolant leakage from the assembly gaps, avoiding safety hazards such as electrical short circuits, insulation failure, and reduced heat dissipation capacity caused by leakage. This sealing structure is simple and reliable, capable of withstanding long-term coolant pressure fluctuations and temperature changes, ensuring the sealing and stability of the cooling system and extending the device's service life.

[0026] 10. This invention employs a step-by-step assembly and circulating heat dissipation process, involving orderly steps such as substrate preparation, heat sink assembly, pipe series connection, coolant filling, device mounting, and circulating heat dissipation. This achieves standardized implementation of a discrete series heat dissipation solution, solving the problems of poor assembly flexibility and inability to adapt to different numbers of series-connected devices in traditional integrated heat dissipation devices. The method has a clear and controllable process, allowing for flexible adjustment of the number of heat dissipation units based on the number of series-connected power devices, resulting in strong adaptability. During operation, the heat dissipation conditions of each device are consistent, effectively suppressing switching oscillations, reducing switching losses, ensuring dynamic voltage equalization, and significantly improving the operational stability and service life of the high-voltage series module. Attached Figure Description

[0027] The accompanying drawings are provided to better understand the invention and are not intended to unduly limit the scope of the invention. Wherein: Figure 1 This is a schematic diagram of the structure of a heat dissipation device with discrete and connected heat dissipation units according to the present invention; Figure 2 This is a top view of a heat dissipation device with discrete and connected heat dissipation units according to the present invention; Figure 3 This is a front view of a heat dissipation device with discrete and connected heat dissipation units according to the present invention; Figure 4 This is a side view of a heat dissipation device with discrete and connected heat dissipation units according to the present invention.

[0028] The reference numerals in the attached drawings are as follows: 1-substrate; 2-sealing ring; 3-heat sink; 4-power device; 5-coolant pipe. Detailed Implementation

[0029] The following description, in conjunction with the accompanying drawings, illustrates exemplary embodiments of the present invention, including various details to aid understanding. These details should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the invention. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0030] This invention discloses a discrete series-connected liquid cooling heat dissipation device and method for low distributed capacitance, belonging to the field of electronic device heat dissipation technology. The heat dissipation device includes several heat dissipation units, with a power device mounted on top of each unit. Adjacent heat dissipation units are connected by coolant pipes. Each heat dissipation unit includes a base and a heat sink. The coolant pipe runs through the interior of the base, and a mounting hole is provided at the center of the top of the base. The heat sink is installed in the mounting hole, with the lower half of the heat sink extending into the internal flow channel of the coolant pipe. The top of the heat sink is used to place the power device. This invention adopts a discrete series-connected heat dissipation unit structure, with the coolant pipe running through the base of each unit and the lower half of the heat sink extending into the internal flow channel of the pipe. Each unit independently corresponds to a power device. This solves the parasitic distributed capacitance problem caused by shared metal heat sinks, eliminates resonant circuits, suppresses switching oscillations, reduces losses, ensures uniform heat dissipation and dynamic voltage equalization, and improves the stability and service life of high-voltage series modules.

[0031] The technical solution of the liquid cooling heat dissipation device and method for discrete series low-distribution capacitors of the present invention will be described below with reference to the embodiments and accompanying drawings.

[0032] Example 1 like Figure 1-4As shown, a discrete series-connected liquid cooling heat dissipation device with low distributed capacitance is provided. It is a heat dissipation device with discrete series-connected heat dissipation units, including several heat dissipation units. A power device 4 is installed above each heat dissipation unit. Adjacent heat dissipation units are connected by a coolant pipe 5. Each heat dissipation unit includes a base 1 and a heat sink 3. The coolant pipe 5 penetrates the interior of the base 1. A mounting hole is opened at the center of the top of the base 1. The heat sink 3 is installed in the mounting hole. The lower half of the heat sink 3 extends into the internal flow channel of the coolant pipe 5. The top of the heat sink 3 is used to place the power device 4. Each heat dissipation unit is an independent heat dissipation module, corresponding one-to-one with a single power device 4, achieving independent heat dissipation for each device. The coolant pipe 5 connects all heat dissipation units in series, forming a unified coolant circulation path, ensuring consistent coolant parameters and heat dissipation conditions for each unit. The base 1 serves as the supporting structure for each heat dissipation unit, providing precise installation positioning and structural support for the coolant pipe 5 and the radiator 3, ensuring overall assembly accuracy and structural stability. The mounting holes at the top serve as dedicated assembly interfaces for the radiator 3, allowing it to directly extend into the internal flow channel of the coolant pipe 5, eliminating additional thermal resistance from the intermediate heat-conducting medium. During operation, the heat generated by the power device 4 is conducted from the bottom surface to the top of the corresponding radiator 3, and then directly transferred through the lower half of the radiator 3 to the coolant flowing within the coolant pipe 5. The coolant circulates along the pipe, carrying the heat out of the device. Adjacent heat dissipation units are connected in series via the coolant pipe 5, with all units in the same cooling loop and identical heat dissipation conditions. This split structure abandons the traditional design of sharing a single metal heat sink, fundamentally avoiding the problem of large-area parasitic distributed capacitance caused by a common heat dissipation base. It effectively suppresses voltage and current oscillations when power devices are switching, reduces switching losses, and ensures uniform dynamic voltage distribution of each series power device, thereby improving the operational reliability of the high-voltage series module.

[0033] Specifically, the radiator 3 includes an immersion section and a heat-conducting section. The heat-conducting section is a plate-shaped platform, and the immersion section includes several heat sinks. The top of the immersion section is fixedly connected to the bottom of the heat-conducting section, and the immersion section is in contact with the coolant in the coolant pipe 5. The heat-conducting section serves as the mounting surface for the power device 4. Its flat plate-shaped structure ensures full contact with the bottom surface of the power device 4, enabling it to evenly receive the heat generated by the power device 4 and quickly conduct it to the immersion section along its own structure. The immersion section extends downwards into the internal flow channel of the coolant pipe 5, and the numerous heat sinks on its surface significantly increase the effective contact area between the radiator 3 and the coolant, enhancing the convective heat transfer effect and allowing the heat transferred from the heat-conducting section to be quickly released into the flowing coolant. The immersion section and the heat-conducting section are fixedly connected using an integral molding process, eliminating the contact thermal resistance caused by segmented assembly, ensuring a continuous and smooth heat conduction path, and preventing heat accumulation at the connection interface. During operation, heat is conducted from the bottom surface of the power device 4 to the heat-conducting section, and then evenly diffused and transferred to the surface of each heat sink in the immersion section. It exchanges heat fully with the coolant flowing through the gaps between the heat sinks, achieving efficient heat transfer. The heat transfer coefficient is significantly improved compared to the smooth cylindrical structure, further ensuring the heat dissipation effect of high-power devices.

[0034] Specifically, the coolant pipe 5 includes a first section, a second section, and a third section arranged sequentially, with the outer diameters of the first and third sections being smaller than that of the second section. The middle second section is the main heat exchange section, corresponding to the installation position of the base 1 and the radiator 3. Its larger outer diameter increases the flow cross-sectional area inside the pipe, reducing the coolant flow velocity in this section and extending the contact time between the coolant and the immersion section of the radiator 3, ensuring sufficient heat exchange. The first and third sections at both ends are variable-diameter connecting sections. Their smaller outer diameters connect the external circulation pipe to adjacent heat dissipation units, smoothly transitioning coolant flow velocity changes, reducing eddies and pressure losses when fluid enters and exits the main heat exchange section, and lowering the driving power consumption of the circulation pump. During operation, the coolant enters from the first variable-diameter connecting section, undergoes diffusion and deceleration, and flows smoothly into the second main heat exchange section. It then sequentially exchanges heat with the immersion sections of each radiator 3, carrying heat before flowing out through the third variable-diameter connecting section to the next unit or external heat dissipation system. This three-section variable diameter structure optimizes the flow field distribution of the coolant, avoids insufficient heat exchange caused by excessive local flow velocity, ensures uniform heat exchange in each heat dissipation unit, reduces pipe resistance, and improves the overall operating efficiency of the cooling system.

[0035] Specifically, a sealing groove is formed on the inner wall of the mounting hole, and a sealing ring 2 is installed in the sealing groove. The sealing groove on the inner wall of the mounting hole provides precise positioning and installation space for the sealing ring 2. The groove size precisely matches the sealing ring 2, ensuring that the sealing ring 2 is fixed in position after assembly and will not shift or fall off, thus ensuring the accuracy of the sealing position. The sealing ring 2 is made of an elastic material resistant to coolant corrosion. After assembly, it undergoes elastic deformation due to the compression between the outer wall of the radiator 3 and the sealing groove, which can fully fill the tiny assembly gap between the outer wall of the radiator 3 and the inner wall of the mounting hole, achieving a static seal in the internal flow channel of the coolant pipe 5. During operation, the coolant pressure in the coolant pipe 5 further compresses the sealing ring 2, forming a self-tightening seal. The higher the coolant pressure, the tighter the seal, effectively preventing coolant leakage from the assembly gap of the mounting hole and avoiding problems such as electrical short circuits, insulation failure, and reduced heat dissipation capacity caused by leakage. This sealing structure is easy to assemble, has reliable sealing performance, and can adapt to long-term changes in coolant temperature and pressure, ensuring the sealing stability and service life of the cooling system.

[0036] Example 2 A second type of discrete series-connected liquid cooling heat dissipation device with low distributed capacitance is provided. This device features discrete series-connected heat dissipation units, with both the substrate 1 and the radiator 3 made of metal. The coolant pipe 5 is made of insulating material. The metal substrate 1 possesses excellent structural strength and deformation resistance, providing stable installation support for the coolant pipe 5 and radiator 3. It can withstand the tightening stress during assembly and the coolant pressure load under operating conditions. Furthermore, the high precision of metal processing and mature forming technology facilitate precise assembly and sealing, making it suitable for mass production. The metal radiator 3 has high thermal conductivity, enabling rapid heat transfer from the power device 4 with minimal thermal resistance, ensuring efficient heat dissipation under high-power conditions and preventing heat accumulation and overheating. During operation, the heat generated by the power device 4 is rapidly conducted to the coolant through the metal radiator 3. The metal substrate 1 maintains the stability and assembly precision of the overall structure, resisting deformation and loosening. This design is suitable for high-power, high-load applications, ensuring excellent heat dissipation performance while also considering structural reliability and manufacturing economy.

[0037] The metal substrate can be precision machined to achieve high-precision dimensional control of the top mounting holes and inner sealing grooves, resulting in excellent machining consistency. This ensures a precise sealing fit with the heat sink and sealing ring, maintaining stable assembly gaps and reliable sealing performance over long-term operation. The metal heat sink is manufactured using a one-piece molding process, eliminating contact thermal resistance between the immersion section and the heat conduction section, ensuring a continuous and smooth heat transfer path. The heat sink fins in the immersion section, leveraging the high thermal conductivity of metal, significantly improve convective heat transfer efficiency, fully releasing heat from the device and meeting the high heat flux density cooling requirements of high-power devices.

[0038] Insulated coolant pipes, while establishing a unified circulation path and ensuring consistent heat dissipation conditions for each unit, can completely block the conductive path between adjacent metal substrates, prevent electrical coupling between heat dissipation units through the cooling circuit, maintain the discrete insulation characteristics of each heat dissipation unit, control parasitic distributed capacitance at a low level, and meet the insulation performance requirements of high-voltage series operation while retaining the structural strength advantages of the metal substrate.

[0039] Example 3 A third type of discrete series-connected liquid cooling heat dissipation device with low distributed capacitance is provided. This device consists of discrete series-connected heat dissipation units. The substrate 1 is made of metal, and the radiator 3 is made of ceramic. The coolant pipe 5 is made of insulating material. The metal substrate 1 ensures the mechanical strength and installation adaptability of the overall structure, stably supporting the coolant pipe 5 and the ceramic radiator 3, and withstanding external loads during assembly and operation. Furthermore, the metal substrate is easy to process and form, with easily controlled dimensional accuracy, facilitating mass production. The ceramic radiator 3 possesses both good thermal conductivity and excellent electrical insulation properties, effectively blocking the electrical coupling path between the power device 4 and the coolant circuit, reducing parasitic distributed capacitance, and improving electrical safety performance under high-voltage conditions. During operation, the heat generated by the power device 4 is efficiently conducted to the coolant through the ceramic radiator 3. The metal substrate 1 maintains the stability of the overall structure, while the ceramic radiator 3 provides electrical isolation from the heat exchange end, preventing capacitive coupling between the device and the cooling system. This ensures heat dissipation capacity while improving the electrical performance of the series-connected devices, balancing structural strength and insulation requirements.

[0040] The metal substrate can be precision machined to achieve high-precision forming of mounting holes and sealing grooves, providing a stable mounting benchmark and assembly support for the ceramic radiator. This adapts to the assembly tolerance requirements of ceramic components, ensuring assembly sealing and structural stability. The ceramic radiator adopts a one-piece sintering molding process, with no contact thermal resistance between the immersion section and the heat conduction section, resulting in uniform and stable heat conduction. The ceramic material itself has excellent electrical insulation properties, completely blocking the electrical coupling path between power devices and the coolant circuit at the heat exchange core. Simultaneously, it exhibits excellent resistance to coolant corrosion, with no performance degradation even after long-term immersion, resulting in a long service life.

[0041] The coolant pipes made of insulating material and the ceramic heat sink form a double electrical isolation barrier. The pipes block the conductive path between adjacent metal substrates, and the heat sink blocks the coupling path between the device and the cooling circuit. The synergistic effect of the two can significantly reduce the parasitic distributed capacitance of the system, effectively suppress switching oscillation, and further improve the electrical safety redundancy under high voltage conditions.

[0042] Example 4 A fourth type of discrete series-connected liquid cooling heat dissipation device with low distributed capacitance is provided. This device consists of discrete series-connected heat dissipation units. The substrate 1 is made of insulating material, and the heat sink 3 is made of metal. The coolant pipe 5 is made of either insulating or non-insulating material. The insulating substrate 1 completely isolates the electrical connection path between adjacent heat sinks 3, eliminating electrical coupling between heat dissipation units at the structural level, significantly reducing parasitic distributed capacitance between series-connected power devices 4, effectively suppressing voltage and current oscillations during switching, and improving the operational stability of the high-voltage series module. The metal heat sink 3 ensures efficient heat conduction, quickly transferring the heat generated by the power devices 4 to the coolant, meeting the heat dissipation requirements of high-power devices and preventing overheating. During operation, each metal heat sink 3 independently conducts heat to its corresponding power device 4. Heat is rapidly transferred to the coolant through the metal heat sink 3, while the insulating substrate 1 maintains electrical isolation between heat dissipation units, with no conductive path between units. This solution ensures both high heat dissipation efficiency and reduces parasitic capacitance at its source, balancing heat dissipation performance and electrical isolation performance.

[0043] The insulating substrate can be mass-produced through processes such as molding and injection molding, making processing costs controllable. It also possesses excellent resistance to coolant corrosion and is less prone to performance degradation during long-term operation in a coolant environment. It achieves physical and electrical isolation between each heat dissipation unit at the structural carrier level, ensuring no electrical continuity between units even if the coolant pipes use non-insulating materials, thus reducing parasitic distributed capacitance at its source. The metal heat sink employs a one-piece molding process, eliminating contact thermal resistance between the heat-conducting section and the immersion section. The immersion section's heatsink fins significantly increase the heat exchange area, achieving efficient convective heat transfer thanks to the high thermal conductivity of the metal. This fully meets the high heat flow dissipation requirements of high-power devices, preventing overheating and heat buildup.

[0044] The selection of materials for coolant piping offers high flexibility: when using insulating materials, double electrical isolation can be formed with the insulating substrate, further reducing system parasitic parameters and improving the safety level under high-pressure conditions; when using non-insulating metallic materials, the structural strength and pressure resistance of the piping can be taken into account, making it suitable for high-pressure, high-flow-rate cooling circulation scenarios without compromising the electrical independence of each heat dissipation unit.

[0045] Example 5 A fifth type of discrete series-connected liquid cooling heat dissipation device with low distributed capacitance is provided. This device features discrete series-connected heat dissipation units, with both the substrate 1 and the radiator 3 made of ceramic material. The coolant pipe 5 is made of either insulating or non-insulating material. The all-ceramic structure achieves complete insulation of the heat dissipation units. Both the ceramic substrate 1 and the ceramic radiator 3 possess excellent electrical insulation properties, completely blocking electrical coupling paths between heat dissipation units and between the power device 4 and the cooling system. This reduces parasitic distributed capacitance to extremely low levels, allowing it to withstand higher voltage stresses and adapting to high-voltage power device series applications. Simultaneously, the ceramic material possesses good thermal conductivity, temperature resistance, and corrosion resistance, enabling stable operation in a coolant environment for extended periods without chemical corrosion or performance degradation, resulting in a long service life. During operation, the heat generated by the power device 4 is efficiently conducted to the coolant through the ceramic radiator 3. The ceramic substrate 1 provides stable structural support and full-dimensional electrical isolation, exhibiting a high overall insulation level and excellent parasitic parameters. This makes it particularly suitable for high-voltage, high-frequency power device series modules, significantly improving the device's operational reliability and electrical safety performance.

[0046] The ceramic substrate possesses excellent structural rigidity and dimensional stability, providing precise installation positioning and structural support for coolant pipes and ceramic radiators. Simultaneously, its superior insulation properties completely block electrical coupling paths between heat dissipation units at the carrier level, forming a fully insulated heat dissipation unit together with the ceramic radiator. The ceramic radiator employs a one-piece sintering process, with no contact thermal resistance between the immersion section and the heat conduction section, ensuring uniform and stable heat transfer. It combines excellent thermal conductivity with extreme insulation, completely blocking electrical coupling between power devices and the cooling circuit from the heat exchange end. Furthermore, it exhibits outstanding temperature and corrosion resistance, showing no performance degradation even after long-term operation in a coolant environment, and its service life far exceeds that of conventional metal components.

[0047] Since the heat dissipation unit has achieved a fully insulated design, the selection of coolant pipe materials is not limited by electrical performance: when using insulating materials, a full-circuit insulation system can be constructed, further improving the safety redundancy under high-voltage conditions and adapting to ultra-high voltage application scenarios; when using non-insulating metal materials, the structural strength and pressure resistance of the pipes can be improved, adapting to high flow rate and high pressure cooling cycle conditions, without compromising the electrical independence of each heat dissipation unit, making the solution highly adaptable.

[0048] Example 6 This embodiment provides a liquid cooling heat dissipation method for discrete series-connected low-distribution capacitance, which is a heat dissipation method for discrete series-connected heat dissipation units. Based on the heat dissipation device with discrete series-connected heat dissipation units described in Embodiment 1, it is characterized by including the following steps: Step S1: Prepare several bases 1, so that the coolant pipes 5 pass through the interior of each base 1, and pre-open an installation hole at the top center of each base 1; Step S2: Fix the radiator 3 in each of the mounting holes so that the lower half of the radiator 3 extends into the internal flow channel of the coolant pipe 5; Step S3: Seal and connect two adjacent substrates 1 through coolant pipes 5, so that all coolant pipes 5 in the substrates 1 are connected in sequence to form an overall cooling circuit, constituting several discrete series heat dissipation units. Step S4: Fill the connected overall cooling circuit with coolant so that the coolant fills all the internal flow channels of the coolant pipes 5; Step S5: Place the multiple power devices 4 connected in series on top of the heat sink 3 in each heat dissipation unit respectively; Step S6: Drive the coolant to circulate within the overall cooling circuit. The heat generated by the power device 4 is transferred to the coolant in the coolant pipe 5 through the radiator 3, and the circulating coolant carries the heat away.

[0049] In step S1, the base 1, serving as the structural support for a single heat dissipation unit, is precision-machined from a corresponding blank according to the design. The coolant pipe 5 penetrates the interior of the base 1 through integral casting or press-fitting, with a tight fit between the outer wall of the pipe and the base 1 to ensure structural strength and sealing performance. This also ensures that the pipe sections within each base are coaxially aligned, providing a precision basis for subsequent series connection. An installation hole at the center of the top of the base 1 extends vertically to the top wall of the coolant pipe 5, with the hole position precisely aligned with the center of the pipe flow channel. The hole diameter precisely matches the assembly dimensions of the radiator 3, providing a reference for the radiator's positioning, installation, and sealing. This step completes the prefabrication of the base and flow channel for a single heat dissipation unit, ensuring the processing accuracy and sealing reliability of the unit structure, forming a standardized heat dissipation unit module, and providing a basis for subsequent flexible assembly.

[0050] Specifically, in step S2, the heat sink 3 is inserted vertically downwards along the mounting hole, with its lower half completely extending into the core area of ​​the internal flow channel of the coolant pipe 5. This ensures that the immersion structure is entirely within the mainstream area of ​​the coolant, allowing for sufficient heat exchange through contact with the coolant. A sealing structure is provided between the mating surfaces of the heat sink 3 and the mounting hole to fill the assembly gap and achieve a static seal, preventing coolant leakage from the installation gaps. The top surface of the heat sink 3 remains horizontal and its flatness meets the device mounting requirements, ensuring a tight fit after the subsequent power device is installed. This step completes the assembly of the core heat-conducting components, establishing a direct heat conduction path from the device mounting surface to the coolant flow channel. This eliminates the additional thermal resistance introduced by the insulation layer in traditional indirect heat conduction structures, providing a structural foundation for efficient convection heat transfer.

[0051] Specifically, in step S3, adjacent substrates 1 are sealed or fastened together through the mating ends of coolant pipes 5. Sealing elements are installed on the mating end faces to prevent coolant leakage. After connection, the internal flow channels of all pipes are sequentially connected, forming a continuous and unified coolant circulation path. Each substrate 1 maintains an independent structural state, connected only through coolant pipes 5, and is electrically isolated, thus forming multiple discrete series-connected heat dissipation units. This step integrates independent heat dissipation units into a complete cooling system. The unified circulation loop ensures that the coolant temperature, flow rate, and other heat dissipation conditions of each unit are completely consistent, while maintaining the electrical independence of each unit. Furthermore, the number of units can be flexibly adjusted according to the number of series-connected power devices, resulting in strong modular assembly adaptability.

[0052] Specifically, in step S4, coolant is filled into the cooling circuit using a vacuum injection method. First, the air inside the circuit is extracted to a low-pressure state, then filtered and purified coolant is injected. The pressure difference drives the coolant to fill all pipe channels. The injection is completed after confirming there are no residual air bubbles through the exhaust port at the end of the circuit. The coolant is a low-conductivity heat exchange medium, balancing heat exchange efficiency and electrical insulation performance. This step thoroughly eliminates air pockets in the channels, ensuring that the immersed portion of the radiator is completely enveloped by coolant, fully utilizing the entire heat exchange area, avoiding air gaps that could reduce heat exchange efficiency, and the pure coolant reduces channel blockage and material corrosion, ensuring long-term stable operation of the cooling system.

[0053] Specifically, in step S5, before placing the power device 4, a thermally conductive interface material is uniformly coated on the top surface of the heat sink 3 to fill the microscopic gaps between the bottom surface of the device and the top surface of the heat sink, eliminating air from the gaps and significantly reducing the interface contact thermal resistance. Each power device 4 is placed one-to-one on top of the heat sink 3 of a heat dissipation unit, and uniform clamping pressure is applied to ensure a tight fit. The power devices 4 are connected in series according to the circuit topology requirements. This step establishes a stable thermally conductive connection between the power device and the heat dissipation unit, ensuring that the heat generated by the device can be efficiently conducted to the heat sink. At the same time, the one-to-one independent corresponding structure maintains electrical isolation between the series devices, structurally avoiding the large-area parasitic capacitance problem caused by a common heat dissipation structure.

[0054] Specifically, in step S6, a circulating pump provides circulation power to the coolant, enabling it to flow continuously and directionally within the overall cooling circuit. The heat generated by the power device 4 is first conducted to the heat sink 3 through the contact surface, and then transferred to the flowing coolant via forced convection heat transfer through the immersion structure of the heat sink 3. The coolant carrying heat flows out of the heat dissipation device and enters an external heat exchange unit to release heat and cool down. The cooled coolant then flows back into the device, completing the circulating heat dissipation process. This step achieves continuous heat transfer and discharge, ensuring that the power device operates within a safe temperature range for a long time. At the same time, the discrete series heat dissipation structure fundamentally suppresses the resonant circuit formed by parasitic distributed capacitance and parasitic inductance, reduces switching oscillation and switching losses, ensures dynamic voltage equalization of each series device, and significantly improves the operational stability and service life of the high-voltage series module.

[0055] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0056] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can occur depending on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A liquid-cooled heat dissipation device with discrete series-connected low distributed capacitance, characterized in that, It includes several heat dissipation units, each of which is used to place a power device (4) on its top. Adjacent heat dissipation units are connected by a coolant pipe (5). Each heat dissipation unit includes a base (1) and a radiator (3). The coolant pipe (5) passes through the interior of the base (1). The top center of the base (1) is provided with a mounting hole. The radiator (3) is installed in the mounting hole. The lower half of the radiator (3) extends into the internal flow channel of the coolant pipe (5). The top of the radiator (3) is used to place the power device (4).

2. The liquid cooling heat dissipation device with discrete series low distributed capacitance according to claim 1, characterized in that, The radiator (3) includes an immersion section and a heat conduction section. The heat conduction section is a plate-shaped platform. The immersion section includes several heat dissipation fins. The top of the immersion section is fixedly connected to the bottom of the heat conduction section. The immersion section is in contact with the coolant in the coolant pipe (5).

3. The liquid cooling heat dissipation device with discrete series low distributed capacitance according to claim 1, characterized in that, The coolant pipe (5) includes a first section, a second section and a third section arranged in sequence, wherein the outer diameter of the first section and the third section is smaller than the outer diameter of the second section.

4. The liquid cooling heat dissipation device with discrete series low distributed capacitance according to claim 1, characterized in that, Both the substrate (1) and the radiator (3) are made of metal.

5. A liquid cooling heat dissipation device with discrete series low distributed capacitance according to claim 1, characterized in that, The substrate (1) is made of metal material, and the radiator (3) is made of ceramic material.

6. A liquid cooling heat dissipation device with discrete series low distributed capacitance according to claim 1, characterized in that, The substrate (1) is made of insulating material, and the radiator (3) is made of metal material.

7. A liquid cooling heat dissipation device with discrete series low distributed capacitance according to claim 1, characterized in that, Both the substrate (1) and the radiator (3) are made of ceramic material.

8. A liquid-cooled heat dissipation device with discrete series low-distribution capacitance according to claim 4 or 5, characterized in that, The coolant pipe (5) is made of insulating material.

9. The liquid cooling heat dissipation device with discrete series low distributed capacitance according to claim 1, characterized in that, A sealing groove is provided on the inner side wall of the mounting hole, and a sealing ring (2) is provided in the sealing groove.

10. A liquid cooling heat dissipation method for discrete series low-distribution capacitors, based on the liquid cooling heat dissipation device for discrete series low-distribution capacitors according to any one of claims 1-9, characterized in that, It includes the following steps: Step S1: Prepare several substrates (1) so that the coolant pipe (5) passes through the interior of each substrate (1) and pre-open an installation hole at the top center of each substrate (1); Step S2: Fix the radiator (3) in each of the mounting holes so that the lower half of the radiator (3) extends into the internal flow channel of the coolant pipe (5); Step S3: Seal and connect two adjacent substrates (1) through coolant pipes (5) so that the coolant pipes (5) in all substrates (1) are connected in sequence to form an overall cooling circuit, which constitutes several discrete series heat dissipation units; Step S4: Fill the connected overall cooling circuit with coolant so that the coolant fills the internal flow channels of all coolant pipes (5); Step S5: Place the multiple power devices (4) connected in series on top of the heat sink (3) in each heat dissipation unit respectively; Step S6: Drive the coolant to circulate in the overall cooling circuit. The heat generated by the power device (4) is transferred to the coolant in the coolant pipe (5) through the radiator (3), and the heat is carried out by the circulating coolant.

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