A cpak power module inverter brick

Abstract

The application relates to the technical field of power semiconductor modules, and discloses a CPAK power module inverter brick, which comprises a capacitor, a driving plate, a base and a power module arranged on the base. The base is provided with a water channel inlet, a water channel outlet, a first embedding area and a second embedding area, a first flow channel on a heat dissipation bottom plate is arranged in the first embedding area and below a CPAK welding area, and a second flow channel is arranged below the second embedding area and corresponds to the capacitor; the first flow channel and the second flow channel are in communication with the water channel inlet and the water channel outlet. The CPAK module comprises symmetrically-arranged upper and lower bridge arm chip groups, positive copper clamps, negative copper clamps and a silver paste layer connecting structure. The inverter brick can cool the CPAK module and the capacitor at the same time, reduces loop inductance and switching peak, reduces external connecting components, and improves the integration, heat dissipation efficiency and reliability.

Description

Technical Field

[0001] This invention relates to the field of power semiconductor module technology, and more specifically, to a CPAK power module inverter brick. Background Technology

[0002] With the development of new energy vehicles, electric construction machinery, energy storage converters, and high-power-density electric drive systems, inverters are evolving towards higher power density, higher efficiency, miniaturization, lightweighting, and modularization. As the core component of an inverter, the power module's packaging structure, current path, heat dissipation capacity, and integration with the drive board, capacitors, and cooling system directly affect the inverter's size, efficiency, reliability, and overall vehicle layout flexibility.

[0003] Currently, TPAK power devices have become a packaging focus in the industry due to their mass application in electric drive systems. TPAK packages typically exist in single-tube form, and multiple TPAK single-tube modules need to be connected in parallel or arranged in an array when building a three-phase full-bridge inverter. For example, in high-power applications, a large number of TPAK single-tube modules are usually required in conjunction with external busbars, connecting copper busbars, bolted connection structures, and heat sinks to form a power module.

[0004] However, existing TPAK multi-tube parallel solutions still have the following problems: First, TPAK is usually a single-switch unit. When building a three-phase full-bridge inverter, a large number of single-tube modules need to be combined. The number of external copper busbars, busbars, solder joints, bolt connection points and assemblies is large, resulting in a complex overall structure and large size, which is not conducive to the miniaturization and platform layout of the inverter.

[0005] Secondly, when multiple chips or individual transistors are connected in parallel, the parasitic inductance and resistance between different parallel branches are difficult to be completely consistent, which can easily lead to uneven current distribution between chips or individual transistors. Some chips or devices may be subjected to high current stress for a long time, resulting in severe local heating and decreased reliability, while the utilization rate of some chips or devices is insufficient, reducing the performance redundancy of the entire power module.

[0006] Third, with the widespread application of silicon carbide power devices, SiC devices have higher switching speeds, and the dv / dt and di / dt during the turn-on and turn-off processes are significantly improved. If there is a large parasitic inductance in the power circuit, it is easy to generate high turn-off voltage spikes and electromagnetic interference, affecting the device's safe operating margin and the overall electromagnetic compatibility performance.

[0007] Fourth, existing power module heat dissipation solutions typically focus primarily on cooling the power chips, while neglecting the heat dissipation of heat sources such as capacitors. In the high-power-density integrated structure of inverters, capacitors are located close to the power modules, and capacitor temperature rise can affect their lifespan and stability; if a separate independent capacitor cooling structure is set up, it will increase the system size and manufacturing cost.

[0008] Fifth, traditional power modules typically employ aluminum bonding wires or complex busbar connection structures, resulting in problems such as long connection paths, numerous solder joints, large parasitic parameters, and limited power cycle life. These problems are even more pronounced in high-frequency, high-voltage, and high-current silicon carbide inverter systems.

[0009] Therefore, a new power module inverter brick structure is needed to reduce the number of external connectors and the overall size, reduce loop inductance, improve the current balance of parallel chips, and provide synergistic cooling for silicon carbide chips and capacitors, thereby improving the power density, reliability and modular scalability of the inverter brick. Summary of the Invention

[0010] To address the shortcomings of existing technologies, the present invention aims to provide a CPAK power module inverter brick, solving the problems of numerous modules, complex external connections, many solder joints and connection points, large parasitic inductance, uneven current distribution, insufficient heat dissipation paths for chips and capacitors, large inverter brick size, and insufficient reliability in existing TPAK multi-transistor array solutions. The present invention reduces main power circuit stray inductance, reduces switching voltage spikes, improves thermal management, and enhances the integration and modular expansion capabilities of the inverter brick through symmetrical arrangement of upper and lower bridge arm chips within the CPAK module, low-inductance interconnection of positive and negative copper clips, silver paste layer connection, and a collaborative cooling structure for the first and second flow channels.

[0011] To achieve the above objectives, the present invention provides the following technical solution: A CPAK power module inverter brick includes a capacitor, a driver board, a base, and a power module mounted on the base. The base has a water channel inlet, a water channel outlet, a first embedding area, and a second embedding area. A second flow channel is provided below the second embedding area, and the capacitor is mounted in the second embedding area, corresponding to the second flow channel. Thus, the second flow channel can dissipate heat generated during capacitor operation.

[0012] The power module includes a heat sink base plate and at least one CPAK module. The heat sink base plate has at least one CPAK soldering area, to which the CPAK module is soldered and fixed. The heat sink base plate has a first flow channel, which is located within a first embedded area. Both the first and second flow channels are connected to a water channel inlet and a water channel outlet. Thus, coolant can enter the base from the water channel inlet, flow through the first and second flow channels respectively, dissipate heat from the CPAK module and capacitor, and then exit from the water channel outlet.

[0013] The driver board is located above the power module and is electrically connected to the CPAK module via a gate signal pin to control the CPAK module's on and off states.

[0014] Furthermore, the first flow channel is serpentine and positioned below the CPAK soldering area. Since the CPAK module is soldered and fixed to the CPAK soldering area, and the first flow channel is located below the CPAK soldering area, the heat generated by the silicon carbide chip in the CPAK module during operation can be transferred to the first flow channel through the bottom of the CPAK module, the CPAK soldering area, and the heat sink, and then carried away by the coolant flowing through the first flow channel.

[0015] Furthermore, the second flow channel is located below the second embedded area, so that after the capacitor is installed in the second embedded area, the bottom of the capacitor corresponds vertically with the second flow channel, thereby enabling the second flow channel to dissipate heat from the capacitor. After the coolant enters through the water channel inlet, it dissipates heat from both the CPAK module and the capacitor, and finally exits through the water channel outlet.

[0016] Furthermore, the CPAK module includes a plastic-encapsulated housing, gate signal pins, a positive copper layer, an upper bridge arm chipset, a lower bridge arm chipset, gate bonding wires, a three-phase copper layer, a negative copper clip, a gate resistor, and a positive copper clip. The upper and lower bridge arm chipsets are fixed to the positive and three-phase copper layers, respectively, and are symmetrically arranged. The positive copper clip is soldered to the upper bridge arm chipset, and the negative copper clip is soldered to the lower bridge arm chipset. The gate bonding wires are connected to the upper bridge arm chipset, the gate resistor, and the lower bridge arm chipset.

[0017] Furthermore, the upper bridge arm chipset includes two silicon carbide chips, and the lower bridge arm chipset includes two silicon carbide chips, with the four silicon carbide chips arranged symmetrically. This symmetrical arrangement structure makes the main current paths between the parallel chips closer, reducing the uneven current distribution caused by differences in parasitic parameters between the parallel chips.

[0018] Furthermore, the positive copper clip is connected across at least two silicon carbide chips in the upper bridge arm chipset, and the negative copper clip is connected across at least two silicon carbide chips in the lower bridge arm chipset. This copper clip connection method allows for the formation of a large-section, short-path power current connection structure, which, compared to traditional aluminum bonding wire connections, reduces on-resistance and parasitic inductance and improves thermal conductivity.

[0019] Furthermore, a silver paste layer is disposed on both the positive electrode copper layer and the three-phase copper layer. The silicon carbide chip is connected to the corresponding positive electrode copper layer and / or the three-phase copper layer through the silver paste layer, and the positive electrode copper clip and the negative electrode copper clip are connected to the corresponding silicon carbide chip through the silver paste layer. This silver paste layer can be a silver sintered layer, a silver-containing solder layer, or other conductive and thermally conductive connection layer suitable for power semiconductor packaging, used to improve the conductivity, thermal conductivity, and power cycle reliability between the chip, the copper layer, and the copper clip.

[0020] Furthermore, the second flow channel includes an inlet section, a branch section connected to the inlet section, and a confluence section connected to the branch section. The branch section includes multiple spaced-apart bent tributary vanes, and a branch channel is formed between adjacent bent tributary vanes. The branch channel extends in a serpentine, arc, or multi-segment bend shape so that the coolant entering the second flow channel is dispersed and flows through multiple branch channels before converging into the confluence section.

[0021] Furthermore, the first flow channel and the second flow channel are connected in series, the water channel inlet is connected to the first flow channel, the first flow channel is connected to the second flow channel, and the second flow channel is connected to the water channel outlet, so that the coolant first flows under the CPAK welding area and then flows under the capacitor.

[0022] Furthermore, the power module also includes positive and negative plastic brackets, a three-phase plastic bracket, a negative connection copper plate, a three-phase connection copper plate, three-phase terminals, and an insulating top cover. The negative connection copper plate connects to the positive and negative terminals, and the three-phase connection copper plate connects to the three-phase terminals. The positive and negative plastic brackets and the three-phase plastic brackets are fixed to the heat dissipation base plate with bolts, and the insulating top cover covers the CPAK module.

[0023] Furthermore, laser welding is used to connect the negative electrode copper strip to the positive and negative terminals, as well as the three-phase copper strip to the three-phase terminals. Bolts are used to mechanically secure the positive and negative electrode plastic brackets and the three-phase plastic brackets. By using laser welding for the terminal connections in the high-current connection path, and primarily using bolts for mechanical fixation, the contact resistance fluctuations caused by bolt conductive connections can be reduced, improving electrical connection consistency and vibration resistance reliability.

[0024] By adopting the above technical solution, the beneficial effects of the present invention are as follows: 1. This invention uses the CPAK module as the core power unit of the power module, integrating the upper bridge arm chipset, lower bridge arm chipset, positive copper layer, three-phase copper layer, positive copper clip and negative copper clip into the CPAK module. Compared with the external array combination structure of multiple TPAK single tubes, it can reduce the number of external connection copper busbars, busbars, solder joints and assemblies, thereby reducing the size of the inverter brick and improving the integration.

[0025] 2. In this invention, the upper and lower bridge arm chip groups are symmetrically arranged, and each chip group preferably includes two silicon carbide chips, so that the four silicon carbide chips are arranged symmetrically. This structure can improve the consistency of the current path of parallel chips, make the current distribution more uniform, reduce the risk of local chip overload, and improve the redundancy of module performance.

[0026] 3. The present invention uses a positive copper clip to bridge the upper bridge arm chip group and a negative copper clip to bridge the lower bridge arm chip group. The copper clip forms a large cross-section and short path conductive connection structure, which can reduce the stray inductance of the power converter circuit and reduce the voltage spikes, switching losses and electromagnetic interference risks during the high-speed switching process of silicon carbide chips.

[0027] 4. The present invention provides a first embedded area and a second embedded area in the base, and places the first flow channel on the heat dissipation base plate in the first embedded area and the second flow channel in the second embedded area, so that both the first flow channel and the second flow channel are connected to the water channel inlet and the water channel outlet. This enables the CPAK module and the capacitor to be cooled simultaneously in the same base, thereby improving the thermal management capability of the inverter brick.

[0028] 5. In this invention, the first flow channel is serpentine and located below the CPAK welding area, so that the heat of the silicon carbide chip in the CPAK module can be transferred to the coolant in the first flow channel through a shorter path, which helps to reduce the chip junction temperature and improve the continuous output capability and reliability of the CPAK module.

[0029] 6. In this invention, the second flow channel is set to correspond with the capacitor, which can effectively dissipate heat from the capacitor, reduce the capacitor temperature rise, extend the capacitor life, and improve the stability of the inverter in high ripple current and high temperature environments.

[0030] 7. In this invention, the silicon carbide chip, the positive electrode copper clip, and the negative electrode copper clip are all connected to the corresponding copper layer or chip through a silver paste layer, which can improve the electrical and thermal conductivity, reduce the thermal resistance, and improve the power cycle life.

[0031] 8. In this invention, the negative electrode connecting copper sheet and the positive and negative terminals, and the three-phase connecting copper sheet and the three-phase terminals are connected by laser welding. Bolts are mainly used for mechanical fixing, which makes the high current connection path more stable, reduces contact resistance fluctuations, and improves vibration resistance reliability. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of the CPAK power module inverter brick in an embodiment of the present invention; Figure 2 This is a schematic diagram of the power module mounted on the base in an embodiment of the present invention; Figure 3 This is a partial structural diagram of the power module in an embodiment of the present invention; Figure 4 This is a schematic diagram of the internal structure of the CPAK module in an embodiment of the present invention; Figure 5 This is a schematic diagram of the base structure in an embodiment of the present invention; Figure 6 This is a schematic diagram of the heat dissipation base plate in an embodiment of the present invention; Figure 7 This is a schematic diagram comparing the loop inductance of the CPAK module and the TPAK multi-tube combination structure in an embodiment of the present invention.

[0033] Reference numerals: 1-Capacitor; 2-Driver board; 3-Base; 4-Water channel inlet; 5-Water channel outlet; 6-Positive and negative plastic brackets; 7-Screw; 8-Three-phase terminal; 9-Three-phase plastic bracket; 10-Bolt; 11-Insulating top cover; 12-Negative connection copper sheet; 13-Plastic encapsulation shell; 14-Three-phase connection copper sheet; 15-Heat dissipation base plate; 16-Gate signal pin; 17-Positive copper layer; 18-Silicon carbide chip; 19-Gate bonding wire; 20-Three-phase copper layer; 21-Negative copper clip; 22-Gate resistor; 23-Positive copper clip; 24-Second embedding area; 25-First embedding area; 26-CPAK soldering area; 27-First flow channel; 28-Second flow channel; 2801-Inlet section; 2802-Branch section; 2803-Bulk section. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0036] Example 1: Overall Structure like Figure 1 As shown, this embodiment provides a CPAK power module inverter brick, including a capacitor 1, a driver board 2, a base 3, and a power module disposed on the base 3. The driver board 2 is fixed above the power module by screws 7; the power module and the capacitor 1 are mounted together on the base 3.

[0037] The driver board 2 is used to provide gate drive signals to the CPAK module in the power module to control the upper and lower bridge arms in the CPAK module to turn on and off according to a predetermined modulation method, thereby outputting three-phase AC power at the three-phase terminal 8.

[0038] The base 3 serves as both the support and cooling component for the inverter brick, and it is equipped with a water inlet 4 and a water outlet 5. The water inlet 4 is used to introduce coolant, and the water outlet 5 is used to discharge the coolant after heat exchange. The coolant can be an aqueous solution of ethylene glycol, such as a 50% aqueous solution of ethylene glycol, or it can be deionized water, cooling oil, or other cooling media suitable for power electronic systems.

[0039] The base 3 has a first embedding area 25 and a second embedding area 24. The first embedding area 25 is used to accommodate or position the first flow channel 27 on the heat dissipation base plate 15, and the second embedding area 24 is used to install the capacitor 1. The first flow channel 27 is mainly used for heat dissipation of the CPAK module, and the second flow channel 28 is mainly used for heat dissipation of the capacitor 1. Both the first flow channel 27 and the second flow channel 28 are connected to the water channel inlet 4 and the water channel outlet 5, so that the coolant can form a dual heat source cooling path for the power chip and the capacitor within the base 3.

[0040] Example 2: Power Module Structure like Figure 2 and Figure 3 As shown, the power module includes a heat sink base 15 and at least one CPAK module. At least one CPAK soldering area 26 is provided on the heat sink base 15. The CPAK module is soldered and fixed to the corresponding CPAK soldering area 26. The CPAK module can be fixed to the CPAK soldering area 26 by reflow soldering, silver sintering, silver paste soldering, or other connection processes suitable for power semiconductor modules.

[0041] The power module also includes positive and negative plastic brackets 6, three-phase plastic brackets 9, negative connection copper strips 12, three-phase connection copper strips 14, three-phase terminals 8, and an insulating top cover plate 11. The positive and negative plastic brackets 6 support the positive and negative terminals and related copper strip structures, while the three-phase plastic brackets 9 support the three-phase terminals 8 and the three-phase connection copper strips 14. The positive and negative plastic brackets 6 and the three-phase plastic brackets 9 are fixed to the heat dissipation base plate 15 by bolts 10.

[0042] An insulating top cover 11 covers the CPAK module and provides insulation, protection, and vibration-resistant support for the CPAK module, copper connection structure, and terminal connection area. The insulating top cover 11 can be made of high-temperature resistant insulating plastic, epoxy material, composite insulating material, or other insulating materials suitable for the power module packaging environment.

[0043] The negative terminal copper strip 12 is connected to the positive and negative terminals, and the three-phase connecting copper strip 14 is connected to the three-phase terminal 8. The negative terminal copper strip 12 and the three-phase connecting copper strip 14 are used to form a high-current conduction path. Preferably, the negative terminal copper strip 12 and the positive and negative terminals, and the three-phase connecting copper strip 14 and the three-phase terminal 8 are connected by laser welding. The bolts 10 are mainly used for mechanically fixing the positive and negative terminal plastic brackets 6 and the three-phase plastic brackets 9.

[0044] With the above structure, the conductive connection in the high-current connection path is mainly undertaken by the welded connection between the copper sheet and the terminal, rather than by bolt contact conductivity. This reduces contact resistance fluctuations, improves the stability of the conductive path, and enhances the reliability of the power module under vibration conditions.

[0045] Example 3: Internal Structure of the CPAK Module like Figure 4 As shown, each CPAK module includes a plastic encapsulated housing 13, a gate signal pin 16, a positive copper layer 17, an upper bridge arm chipset, a lower bridge arm chipset, a gate bonding wire 19, a three-phase copper layer 20, a negative copper clip 21, a gate resistor 22, and a positive copper clip 23.

[0046] The plastic encapsulation housing 13 is used to encapsulate and protect the silicon carbide chip 18, positive copper layer 17, three-phase copper layer 20, positive copper clip 23, negative copper clip 21, gate bonding wire 19, and gate resistor 22 inside the CPAK module. The plastic encapsulation housing 13 can be made of epoxy molding compound or other insulating encapsulation materials suitable for power semiconductor packaging.

[0047] The positive electrode copper layer 17 is used to form the positive electrode conductive region. The three-phase copper layers 20 are used to form the corresponding phase output conductive regions. The upper bridge arm chip group and the lower bridge arm chip group are fixed on the positive electrode copper layer 17 and the three-phase copper layer 20, respectively, and the upper bridge arm chip group and the lower bridge arm chip group are symmetrically arranged.

[0048] In this embodiment, the upper bridge arm chip group includes two silicon carbide chips 18, the lower bridge arm chip group includes two silicon carbide chips 18, and the four silicon carbide chips 18 are arranged symmetrically. Specifically, the two upper bridge arm silicon carbide chips 18 can be arranged on one side of the positive electrode copper layer 17, and the two lower bridge arm silicon carbide chips 18 can be arranged on the other side of the three-phase copper layer 20.

[0049] The symmetrical arrangement structure described above allows for closer approximation of current path lengths, connection path widths, and parasitic parameters among the parallel chips, thereby reducing current imbalances between different chips. This structure is particularly suitable for high-speed switching applications of silicon carbide devices, helping to reduce the risk of localized overcurrent and overheating.

[0050] The positive copper clip 23 is soldered to the upper bridge arm chipset. Preferably, the positive copper clip 23 bridging at least two silicon carbide chips 18 in the upper bridge arm chipset, so that the two silicon carbide chips 18 in the upper bridge arm form a parallel conductive connection through the positive copper clip 23. The negative copper clip 21 is soldered to the lower bridge arm chipset. Preferably, the negative copper clip 21 bridging at least two silicon carbide chips 18 in the lower bridge arm chipset, so that the two silicon carbide chips 18 in the lower bridge arm form a parallel conductive connection through the negative copper clip 21.

[0051] The positive copper clip 23 and the negative copper clip 21 can be sheet-shaped copper clips, bridge-type copper clips, copper clips with bends, or other copper connectors that can bridge chips and form a large cross-sectional conductive path. Compared with traditional aluminum bonding wires, copper clips have a larger conductive cross-sectional area, a shorter connection path, and better thermal conductivity, which can reduce conduction losses, parasitic inductance, and thermal resistance.

[0052] Gate resistor 22 is positioned between gate signal pin 16 and gate bonding wire 19. Gate signal pin 16 is used for electrical connection with driver board 2 and to receive drive signals. Gate bonding wire 19 is connected to the upper bridge arm chipset, gate resistor 22, and lower bridge arm chipset. The gate drive signal output from driver board 2 enters the CPAK module via gate signal pin 16, and is then transmitted to the gate of the corresponding silicon carbide chip 18 via gate resistor 22 and gate bonding wire 19 to control the turn-on and turn-off of silicon carbide chip 18.

[0053] Because the gate resistor 22 is positioned close to the silicon carbide chip 18, it can reduce the parasitic parameters of the gate circuit, suppress gate oscillations, and improve voltage spikes during the switching process.

[0054] Example 4: Silver paste layer connection structure and manufacturing method A silver paste layer is disposed on both the positive electrode copper layer 17 and the three-phase copper layer 20. The silver paste layer can be a silver sintered layer, a silver-containing solder layer, or a silver-based conductive connection layer. The silicon carbide chip 18 is connected to the corresponding positive electrode copper layer 17 and / or the three-phase copper layer 20 through the silver paste layer. The positive electrode copper clip 23 and the negative electrode copper clip 21 are connected to the corresponding silicon carbide chip 18 through the silver paste layer.

[0055] In one specific manufacturing process, silver paste can be printed first at predetermined positions on the positive electrode copper layer 17 and the three-phase copper layer 20, and then the silicon carbide chip 18 can be mounted at the corresponding positions. Next, positive electrode copper clips 23 and negative electrode copper clips 21 are placed on top of the silicon carbide chip 18, and the silicon carbide chip 18, copper layers, and copper clips are firmly connected through reflow soldering, hot-pressing silver sintering, or other applicable processes. Finally, a plastic encapsulation shell 13 is formed through a molding process, thus obtaining the CPAK module.

[0056] By using a silver paste layer connection structure, the electrical and thermal conductivity between the chip and the copper layer, and between the chip and the copper clamp, can be improved, the interfacial thermal resistance can be reduced, and the power cycle life can be increased.

[0057] Example 5: Base Cooling Structure like Figure 5 As shown, the base 3 has a first embedding area 25 and a second embedding area 24. The first flow channel 27 on the heat dissipation base plate 15 is placed in the first embedding area 25. The second flow channel 28 is located below the second embedding area 24 and corresponds to the capacitor 1.

[0058] The first flow channel 27 is serpentine and positioned below the CPAK soldering area 26. The first flow channel 27 may include multiple parallel straight flow channel segments and bent flow channel segments connecting adjacent straight flow channel segments, creating a longer heat exchange path for the coolant below the CPAK soldering area 26. Since the CPAK module is soldered to the CPAK soldering area 26, the heat generated during CPAK module operation can be transferred from the silicon carbide chip 18 to the bottom of the CPAK module, and then through the CPAK soldering area 26 and the heat sink 15 to the first flow channel 27, where it is carried away by the coolant.

[0059] The second flow channel 28 is located below the second embedded area 24. After the capacitor 1 is installed in the second embedded area 24, the capacitor 1 corresponds vertically to the second flow channel 28. The heat generated by the capacitor 1 during operation can be transferred to the vicinity of the second flow channel 28 through its bottom and carried away by the coolant flowing through the second flow channel 28. The second flow channel 28 includes an inlet section 2801, a branch section 2802, and a confluence section 2803 connected in sequence. The branch section 2802 is composed of an array of multiple bent branch vanes arranged at intervals. Each bent branch vane extends in a serpentine, arc, or multi-segment bend shape, so that the fluid entering the second flow channel 28 can be dispersed into multiple branches and flow along the bend path before re-converging. Through the above structure, the second flow channel 28 can increase the fluid flow path and effective contact area in a limited space, improve the uniformity of fluid distribution, enhance fluid disturbance and heat transfer, mass transfer, or mixing effects, reduce local dead zones and short-circuit flow phenomena, thereby improving the overall flow channel structure's working stability and heat dissipation efficiency.

[0060] The first flow channel 27 and the second flow channel 28 are both connected to the water inlet 4 and the water outlet 5. The coolant first passes through the first flow channel 27 to dissipate heat from the CPAK module, then passes through the second flow channel 28 to dissipate heat from the capacitor 1, and finally is discharged from the water outlet 5.

[0061] In a preferred embodiment, the width, depth, spacing, bend radius, and length of the first flow channel 27 can be set according to the heat flux density and target junction temperature of the CPAK module. The second flow channel 28 can be set according to the heat generation of capacitor 1, allowable temperature rise, and coolant flow rate. This design allows the first and second flow channels 27 and 28 to respectively meet the heat dissipation requirements of the power chip and capacitor, while controlling the overall voltage drop within a reasonable range.

[0062] Example 6: Working Process In practical applications, the positive and negative terminals of the DC power supply are connected to the positive and negative terminals of the inverter brick, respectively. The gate drive signal is input to the CPAK module through the gate signal pin 16, and then transmitted to the gate of the corresponding silicon carbide chip 18 via the gate resistor 22 and the gate bonding wire 19, thereby controlling the on and off of the upper and lower bridge arm chipsets. Through pulse width modulation or other modulation methods, three-phase AC power is output at the three-phase terminal 8 to drive the motor.

[0063] During the operation of the inverter brick, the silicon carbide chip 18 generates heat due to conduction and switching losses, and the capacitor 1 generates heat due to ripple current and equivalent series resistance. Coolant enters through water inlet 4 and flows through the first flow channel 27 and the second flow channel 28. The first flow channel 27 dissipates heat from the CPAK module and its silicon carbide chip 18, while the second flow channel 28 dissipates heat from the capacitor 1. After heat exchange, the coolant exits through water outlet 5.

[0064] Because the CPAK module uses four silicon carbide chips 18 symmetrically arranged inside, and forms a large-section, short-path connection structure through positive copper clips 23 and negative copper clips 21, the non-inductance of the main power circuit is reduced, the current distribution is more uniform, and the risk of switching voltage spikes and electromagnetic interference is reduced. Meanwhile, since the first flow channel 27 is located below the CPAK welding area 26, and the second flow channel 28 is correspondingly located with capacitor 1, both the power chips and the capacitor can be cooled in a targeted manner, improving the thermal stability and reliability of the inverter brick.

[0065] Example 7: Modular Expansion Method like Figure 6As shown, the CPAK modules of this invention can be expanded in number according to different power levels. In lower power level applications, one CPAK module can be set per phase, with three CPAK modules corresponding to three-phase outputs respectively. In higher power level applications, two or more CPAK modules can be set per phase, and multiple CPAK modules can be arranged along the length of the heat dissipation base plate 15.

[0066] When the number of CPAK modules in the same phase is increased, the corresponding three-phase connecting copper sheet 14 can be set as a continuous copper sheet or a segmented copper sheet, so that multiple CPAK modules in the same phase can be connected to the corresponding phase output terminal. Correspondingly, multiple CPAK soldering areas 26 can be set on the heat dissipation base plate 15, and the first flow channel 27 can be correspondingly increased with flow channel branches or extended with flow channel path to ensure that there is still effective heat dissipation capacity under the newly added CPAK module.

[0067] With the above structure, the present invention can flexibly increase the number of CPAK modules according to power requirements without completely redesigning the inverter brick platform, which is conducive to the platform-based development of the whole vehicle and the common platform design of products with different power levels.

[0068] Example 8: Noise Reduction Effect like Figure 7 As shown, the loop clutter inductance of the CPAK power module structure and the TPAK multi-tube combination structure in this embodiment is compared. The comparison results show that at the 0.1000GHz frequency point, the equivalent loop clutter inductance of the TPAK multi-tube combination structure is about 7.5881nH, while the equivalent loop clutter inductance of the CPAK power module structure in this embodiment is about 4.1234nH.

[0069] Therefore, it can be seen that the loop inductance of the CPAK power module structure in this embodiment is reduced by approximately 45.7% compared to the TPAK multi-tube combination structure. This result shows that by integrating the upper bridge arm chipset, lower bridge arm chipset, positive copper layer 17, three-phase copper layer 20, positive copper clip 23, and negative copper clip 21 into the CPAK module, this embodiment shortens the main power commutation path and reduces parasitic inductance, thereby helping to reduce voltage spikes, switching losses, and electromagnetic interference during the high-speed switching process of silicon carbide devices.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any ordinary changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included within the protection scope of the present invention.

Claims

1. A CPAK power module inverter brick, comprising a capacitor, a driver board, a base, and a power module disposed on the base, characterized in that: The base is provided with a water channel inlet, a water channel outlet, a first embedded area and a second embedded area. A second flow channel is provided below the second embedded area. The capacitor is installed in the second embedded area and corresponds to the second flow channel. The power module includes a heat dissipation base plate and at least one CPAK module. The heat dissipation base plate is provided with at least one CPAK welding area. The CPAK module is welded and fixed to the corresponding CPAK welding area. The heat dissipation base plate has a first flow channel. The first flow channel is placed in a first embedding area. The first flow channel and the second flow channel are both connected to the water channel inlet and the water channel outlet. The driver board is positioned above the power module and is electrically connected to the CPAK module to control the CPAK module's on / off state.

2. The CPAK power module inverter brick according to claim 1, characterized in that: The first flow channel is serpentine and located below the CPAK welding area, and the second flow channel is located below the second embedding area, so that the coolant entering from the water channel inlet dissipates heat from the CPAK module and the capacitor respectively and is discharged from the water channel outlet.

3. The CPAK power module inverter brick according to claim 1, characterized in that: The CPAK module includes a plastic-encapsulated shell, gate signal pins, positive copper layer, upper bridge arm chipset, lower bridge arm chipset, gate bonding wire, three-phase copper layer, negative copper clip, gate resistor, and positive copper clip. The upper bridge arm chip group and the lower bridge arm chip group are respectively fixed on the positive electrode upper copper layer and the three-phase upper copper layer, and the upper bridge arm chip group and the lower bridge arm chip group are symmetrically arranged. The positive electrode copper clip is soldered to the upper bridge arm chip group, and the negative electrode copper clip is soldered to the lower bridge arm chip group. The driver board is electrically connected to the CPAK module via a gate signal pin. The gate bonding wire is connected to the upper bridge arm chipset, the gate resistor, and the lower bridge arm chipset.

4. The CPAK power module inverter brick according to claim 3, characterized in that: The upper bridge arm chip group includes two silicon carbide chips, the lower bridge arm chip group includes two silicon carbide chips, and the four silicon carbide chips are arranged symmetrically.

5. The CPAK power module inverter brick according to claim 4, characterized in that: The positive copper clip is connected across at least two silicon carbide chips in the upper bridge arm chipset, and the negative copper clip is connected across at least two silicon carbide chips in the lower bridge arm chipset.

6. The CPAK power module inverter brick according to claim 5, characterized in that: A silver paste layer is provided on both the positive electrode copper layer and the three-phase copper layer. The silicon carbide chip is connected to the corresponding positive electrode copper layer and / or the three-phase copper layer through the silver paste layer. The positive electrode copper clip and the negative electrode copper clip are connected to the corresponding silicon carbide chip through the silver paste layer.

7. The CPAK power module inverter brick according to claim 1 or 2, characterized in that: The second flow channel includes an inlet section, a branch section connected to the inlet section, and a confluence section connected to the branch section. The branch section includes a plurality of spaced-apart bent tributary vanes, and a tributary channel is formed between adjacent bent tributary vanes. The tributary channel extends in a serpentine, arc, or multi-segment bend shape so that the coolant entering the second flow channel flows dispersed through the plurality of tributary channels and then converges into the confluence section.

8. The CPAK power module inverter brick according to claim 7, characterized in that: The first flow channel and the second flow channel are connected in series. The water channel inlet is connected to the first flow channel, the first flow channel is connected to the second flow channel, and the second flow channel is connected to the water channel outlet, so that the coolant first flows below the CPAK welding area and then flows below the capacitor.

9. The CPAK power module inverter brick according to claim 1, characterized in that: The power module also includes positive and negative plastic brackets, three-phase plastic brackets, negative connecting copper plates, three-phase connecting copper plates, three-phase terminals, and an insulating top cover. The negative connecting copper plates are connected to the positive and negative terminals, and the three-phase connecting copper plates are connected to the three-phase terminals. The positive and negative plastic brackets and the three-phase plastic brackets are fixed to the heat dissipation base plate by bolts. The insulating top cover covers the top of the CPAK module.

10. The CPAK power module inverter brick according to claim 9, characterized in that: The negative electrode connecting copper sheet and the positive and negative terminals, as well as the three-phase connecting copper sheet and the three-phase terminals, are all connected by laser welding.

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