Power unit, power module

Abstract

This disclosure relates to a power unit and a power module. The power unit includes: a first metal layer comprising a power region, a low-voltage region, and a high-voltage region arranged sequentially in a first direction; a basic circuit unit including: at least two main switching transistors located in the power region, with their drains electrically connected to the power region and their sources electrically connected to the low-voltage region; an auxiliary switching transistor located in the high-voltage extension region, with its drain electrically connected to the high-voltage extension region and its source electrically connected to the drain of the main switching transistors; a clamping capacitor electrically connected to the low-voltage region and the high-voltage region; the low-voltage region of the first basic circuit unit being electrically connected to the power region of a second basic circuit unit via a connection region; and the low-voltage extension region being electrically connected to the low-voltage region of the second basic circuit unit. The design of clearly separating the high-electric-field and low-electric-field regions within the power unit improves its electrical reliability. The high symmetry of the power module design based on the power unit reduces the module's parasitic inductance and improves the dynamic response speed of the power module.

Description

Technical Field

[0001] This disclosure relates to the field of power electronics technology, and in particular to power units and power modules. Background Technology

[0002] There are numerous medium- and high-voltage power conversion applications in industries such as industry, transportation, power grids, and national defense, creating a strong demand for high-voltage power electronic devices or power modules. For unipolar power electronic devices, the specific on-resistance is directly proportional to the square of the withstand voltage; the higher the withstand voltage, the higher the specific on-resistance, and the greater the losses during operation. To some extent, it can be simply assumed that if the withstand voltage of a device increases fivefold (e.g., from 1200V to 6000V), the device's losses will increase 25 times.

[0003] For traditional silicon-based devices, significantly increasing the voltage level can only be achieved through bipolar device structure design. However, the high switching losses of bipolar devices limit the application of high-voltage bipolar devices. To achieve low-loss, high-voltage, high-power output, the research and development of novel wide-bandgap semiconductor power electronic devices has become an inevitable trend. Silicon carbide (SiC) devices are a typical example of novel wide-bandgap semiconductor devices, characterized by fast switching speed and low losses, and have broad application prospects in power systems. Currently, 1.2kV and below voltage-rated SiC power electronic chips are fully commercialized on a large scale, and their prices are relatively reasonable. However, due to limitations in SiC materials and chip manufacturing technology, low-cost, reliable, high-voltage SiC devices remain a long way off. Therefore, the technology of using series-connected low-voltage, low-loss SiC devices to achieve high-voltage power conversion has become the best choice for medium- and high-voltage power conversion to reduce losses, lower costs, and increase system output power.

[0004] There are two possible solutions for building high-voltage power conversion systems using low-voltage devices: multilevel converter schemes and power device series schemes. Multilevel converter schemes, represented by cascaded H-bridge multilevel converters (CHB) and modular multilevel converters (MMC), feature modular structure, high efficiency, and high reliability, and have been applied in many medium- and high-power conversion applications. However, multilevel converter schemes typically require the use of large-sized passive components. For example, CHB requires a large phase-shifting transformer, while capacitors account for approximately 70% of the size of submodules in MMC. These drawbacks hinder the use of multilevel converters in applications with strict weight and size requirements, such as electrified transportation and data centers.

[0005] Series connection of power electronic devices is another relatively direct way to apply low-voltage power devices to medium- and high-voltage applications. This method improves the voltage withstand rating and increases the output power of the power conversion system. Compared to multi-level technology, it offers advantages such as smaller system size, fewer passive components, and simpler circuit topology. However, due to differences in the electrical performance parameters of power electronic devices and external circuit conditions (e.g., junction capacitance, gate threshold voltage, gate drive signal delay, and instantaneous drive voltage applied to the gate), voltage imbalances in series-connected power electronic devices are highly likely, leading to low electrical reliability of the power conversion system. Therefore, achieving voltage balancing in series-connected devices is a key technology for further improving the voltage and current ratings of power conversion systems using low-voltage power electronic devices.

[0006] Voltage equalization control strategies and hardware optimization design of series topology power loops are the two main technical supports for achieving voltage balance of power devices in series. There are two types of voltage equalization control strategies: input gate-side voltage equalization control and output power-side voltage equalization control.

[0007] The disadvantages of the input gate-side voltage equalization control technology are: complex circuit design and control strategy, extremely high requirements for high-speed sensors and A / D conversion chips, and extreme sensitivity to changes in device temperature and load current. This technology necessitates the introduction of additional circuitry, increasing the complexity of the drive loop. Due to the involvement of high-speed control, the voltage equalization control circuit is costly and lacks practical usability.

[0008] Output power side voltage equalization control technologies include passive snubber circuits and active clamping circuits. Passive snubber circuits, relying on RC (Resistor-Capacitance) circuits, experience significant energy loss in the snubber resistor (R) during practical operation. The large size of passive components hinders integration, and the parallel connection of the snubber capacitor with the power circuit of the switching transistor results in a slower switching speed. However, active voltage clamping circuits, by introducing an auxiliary switching transistor in the clamping branch, feed the energy accumulated in the clamping capacitor back into the circuit instead of directly dissipating it as in RC solutions. This approach introduces less loss into the voltage equalization circuit. Furthermore, the active clamping circuit only clamps when the voltage across the power electronic device exceeds the voltage across the clamping capacitor, thus not reducing the switching speed of the main switching transistor or increasing its switching losses. Therefore, the voltage equalization control strategy based on active clamping circuits is a more ideal solution for addressing voltage equalization in series-connected devices.

[0009] However, current research on active clamp control strategies primarily relies on discrete devices or conventional commercial power modules to build the hardware for series-connected power loops. This presents numerous drawbacks, hindering the large-scale commercialization of power electronic series solutions employing active clamp control strategies. Discrete device-based series solutions suffer from low system power density and difficulty in high-current operation, failing to meet the high-power demands of medium- and high-voltage applications. While standardized commercial module-based series solutions address the high-power requirements of medium- and high-voltage applications, the mismatch between the commercial module power loop topology and the overall architecture of the power conversion system using active clamp control strategies leads to several limitations. These limitations include inconvenient voltage and current level expansion for the power conversion system, long internal power loop lines resulting in significant parasitic inductance, unreasonable main circuit topology of the power module, and low power density or slow dynamic response of the power module and its power conversion system.

[0010] Developing series-topology power modules suitable for active clamping control strategies is of paramount importance for fully validating active clamping technologies in high-voltage, high-power conversion. Developing series-topology power modules also facilitates the industrialization of active clamping technologies in this field. To extend the low-loss and low-cost advantages of low-voltage silicon carbide devices to high-voltage, high-power applications, and gradually replace multi-level or input-gate-side voltage equalization control technologies with numerous drawbacks, it is urgently necessary to develop low-cost high-voltage, high-power modules based on series-connected low-voltage power electronic chips and employing active clamping control strategies. Summary of the Invention

[0011] Therefore, it is necessary to provide a power unit and a power module to address at least one of the above problems.

[0012] This disclosure provides a power unit comprising: a patterned first metal layer and two basic circuit units arranged along a first direction parallel to the first metal layer; a region in the first metal layer corresponding to one basic circuit unit includes a power region, a low-voltage region, a high-voltage region, and a high-voltage extension region, arranged sequentially along the first direction; the high-voltage extension region is electrically connected to the high-voltage region and is located on one side of the power region along a second direction perpendicular to the first direction; the basic circuit unit includes: at least two main switching transistors located in the power region and arranged side-by-side along the second direction, the drain of the main switching transistors electrically connected to the power region, and the source of the main switching transistors electrically connected to the low-voltage region; and an auxiliary switching transistor located in the high-voltage extension region. The circuit comprises: a primary switching transistor, whose drain is electrically connected to the high-voltage extension region, and whose source is electrically connected to the drain of the primary switching transistor; a clamping capacitor, one end of which is electrically connected to the low-voltage region, and the other end of which is electrically connected to the high-voltage region; two basic circuit units, including a first basic circuit unit and a second basic circuit unit, with the high-voltage regions of the first and second basic circuit units facing each other; a first metal layer, including a connection region and a low-voltage extension region, the connection region being electrically connected to the low-voltage region of the first basic circuit unit and also electrically connected to the power region of the second basic circuit unit; and the low-voltage extension region being electrically connected to the low-voltage region of the second basic circuit unit and extending to the side of the high-voltage region of the second basic circuit unit away from the low-voltage region of the second basic circuit unit.

[0013] The power unit provided in this disclosure has a clear separation between the high electric field region and the low electric field region, which can improve electrical reliability. By setting a patterned first metal layer, the electrical connection and layout of each component within the basic circuit unit can be realized, and the operating performance of the power unit can be guaranteed.

[0014] In some embodiments, the connection region and the high-voltage extension region are located on opposite sides of the low-voltage region, and the low-voltage extension region extends to the side of the high-voltage extension region of the second basic circuit unit away from the power region of the second basic circuit unit; the first metal layer includes a power extension region located in the power region of the first basic circuit unit away from the high-voltage extension region of the first basic circuit unit, and the power extension region is electrically connected to the power region of the first basic circuit unit.

[0015] This configuration simplifies the structural design of the power unit, improves symmetry, and helps the power unit achieve a series circuit topology.

[0016] In some embodiments, the area in the first metal layer corresponding to a basic circuit unit further includes at least one terminal pattern, the terminal pattern being located on the side of the power region away from the low-voltage region, and the terminal pattern being electrically connected to a main switch or an auxiliary switch; the basic circuit unit further includes at least one inner signal terminal and at least one outer signal terminal, the inner signal terminal being electrically connected to a clamping capacitor, and the outer signal terminal being electrically connected to the terminal pattern.

[0017] In the power unit, the outer signal terminals for low-voltage signals used to control the operation of the main switch and auxiliary switch are symmetrically distributed on both outer sides of the power unit, while the inner signal terminals for acquiring high-voltage signals from the clamping capacitor are distributed in the active clamping branch area inside the power unit. This creates a clear separation between the high-electric-field region and the low-electric-field region inside the power unit, thereby improving the electrical reliability of the power unit.

[0018] In some embodiments, the region in the first metal layer corresponding to a basic circuit unit further includes a main source bar, a main gate bar, an auxiliary source bar, and an auxiliary gate bar. The main source bar and the main gate bar are located on the side of the power region away from the low-voltage region, and the auxiliary source bar and the auxiliary gate bar are located on the side of the high-voltage extension region away from the high-voltage region along the first direction. At least one outer signal terminal includes: a main gate signal terminal electrically connected to the gate of the main switch transistor through the main gate bar, a main source signal terminal electrically connected to the source of the main switch transistor through the main source bar, an auxiliary gate signal terminal electrically connected to the gate of the auxiliary switch transistor through the auxiliary gate bar, and an auxiliary source signal terminal electrically connected to the source of the auxiliary switch transistor through the auxiliary source bar.

[0019] With this configuration, the first metal layer can aggregate the point connection paths of similar components and ensure the isolation between the external signal terminals and the components. In addition, the design of separating the gate-source circuit on the input side of the switch and the drain-source circuit on the output side also reduces the negative feedback generated by the switch through the common source path during the switching transient, thereby improving the dynamic response speed of the power unit during operation.

[0020] In some embodiments, the main source bar is located between the main gate bar and the power region, and the auxiliary source bar is located between the auxiliary gate bar and the high voltage extension region; in the first basic circuit unit, the main source signal terminal, the main gate signal terminal, the auxiliary gate signal terminal and the auxiliary source signal terminal are arranged in sequence along the second direction and arranged in a row; in the second basic circuit unit, the main source signal terminal, the main gate signal terminal, the auxiliary gate signal terminal and the auxiliary source signal terminal are arranged in sequence along the second direction and arranged in a row.

[0021] This configuration effectively controls the arrangement direction of the external signal terminals, ensuring that the external signal terminals are easy to connect externally, and confines the low electric field region to the outer region of the first metal layer of the power unit, which is conducive to the high-density integration of the drive circuit and the power unit.

[0022] In some implementations, the inner signal terminals in the first basic circuit unit are located on the side opposite to the auxiliary switch relative to the main switch; the inner signal terminals in the second basic circuit unit are located on the same side as the auxiliary switch relative to the main switch.

[0023] This configuration facilitates the external sampling circuit to sample the voltage of the clamping capacitor in the basic circuit unit of the power unit. The layout of the inner signal terminals is compact and has high space utilization. It also facilitates the high-density integration of the external sampling circuit with the power unit, while confining the high electric field region to the internal area of ​​the power unit.

[0024] In some embodiments, the power unit includes a metal-clad substrate structure, which includes a second metal layer, a substrate, and a first metal layer stacked sequentially. The substrate includes a first substrate, a second substrate, and a third substrate that are sequentially disposed and separated from each other along a first direction. The second substrate is provided with a power region, a low-voltage region, a high-voltage region, and a high-voltage extension region of the first basic circuit unit. The power region, low-voltage region, high-voltage region, and high-voltage extension region of the second basic circuit unit, as well as a connection region and a low-voltage extension region, are also provided. The high-voltage region and the high-voltage extension region are integrally formed. The low-voltage region, the connection region, and the power region of the second basic circuit unit of the first substrate circuit unit are integrally formed. The low-voltage region and the low-voltage extension region of the second basic circuit unit are integrally formed.

[0025] This configuration results in a stable and compact power unit structure, which avoids circuit failures caused by deformation, reduces circuit inconsistencies and manufacturing difficulties caused by overhead lead interconnection, and also ensures circuit performance.

[0026] This disclosure also provides a power module, which includes: a first power unit and a second power unit alternately arranged and connected in series, wherein at least one of the first power unit and the second power unit is the aforementioned power unit, and the alternation is in the second direction.

[0027] The series topology power module based on low-voltage electronic chips and employing active clamping voltage equalization control disclosed herein has enormous application prospects and economic value.

[0028] In some embodiments, the first power unit and the second power unit have a symmetrical structure with the vertical plane in the first direction as a mirror.

[0029] This design simplifies the power module's structural design while improving the symmetry of the main power branch's overall path. The proposed technical solution, based on the sequential series connection of the first and second power units, simplifies the main power branch's path into a "square wave" shape, simplifying the expansion of voltage and current ratings and further increasing the power module's power density. The shortened length of the power module in the series direction ensures that the series topology power module maintains high withstand voltage while avoiding technical difficulties caused by deformation during manufacturing. The reduced aspect ratio also improves the power module's manufacturing yield.

[0030] The design of the first metal layer pattern inside the power unit contains close, parallel paths with opposite currents, and a compact "square waveform" power main branch formed by alternating series connection of the first and second power units. This design significantly reduces the parasitic inductance of the main power branch of the power module and greatly improves the dynamic electrical performance of the power module.

[0031] In some embodiments, the power module further includes a metal-clad insulating structure and at least two first solder layers, the at least two first solder layers being arranged sequentially along the metal-clad insulating structure, and the metal-clad substrate structure of the power unit being fixed to the metal-clad insulating structure through the corresponding first solder layers.

[0032] With this configuration, the power module has a stable structure, which can avoid circuit failures caused by deformation and ensure the performance of the circuit.

[0033] In some implementations, the dimension of the insulating plate of the metal-clad insulating structure along the stacking direction is greater than or equal to the quotient obtained by dividing the withstand voltage of the power module by the breakdown field strength of the insulating plate material.

[0034] This configuration effectively ensures the insulation performance of the insulating board and prevents localized breakdown when current or voltage is abnormal.

[0035] In some embodiments, the power module further includes a second welding layer, a base plate, and a frame. The base plate is located on the side of the metal-clad insulating structure opposite to the first welding layer and is fixedly connected to the metal-clad insulating structure through the second welding layer. The four corners of the metal-clad insulating structure are formed with notches to expose the base plate along the stacking direction. The frame surrounds at least two first welding layers and is fixedly connected to the base plate through the notches.

[0036] This design effectively protects the power unit and ensures the overall structural stability of the power module, especially when the power module has a slender shape. By creating notches at the four corners of the metal-clad insulation structure, the metal-clad insulation structure, the base plate, and the frame can be assembled in an interlocking manner, which not only ensures a firm connection between the base plate and the frame but also makes the overall structure stable after manufacturing.

[0037] In some embodiments, the power module may further include at least one of a first freewheeling diode and a second freewheeling diode, wherein the cathode of the first freewheeling diode is electrically connected to the drain of the main switching transistor, the anode of the first freewheeling diode is electrically connected to the source of the main switching transistor, the cathode of the second freewheeling diode is electrically connected to the drain of the auxiliary switching transistor, and the anode of the second freewheeling diode is electrically connected to the source of the auxiliary switching transistor; the withstand voltage of the power module is the product of the withstand voltage of the basic circuit unit and the number of basic circuit units.

[0038] This configuration optimizes the circuit performance of the power module and ensures its effectiveness in high-voltage environments.

[0039] In some embodiments, the power module further includes at least one series connection structure and two electrodes. The series connection structure overlaps two adjacent power units. In the two adjacent power units, the low-voltage extension region of one is electrically connected to the power extension region of the other through the series connection structure. The two power units located at both ends in series are electrically connected to the two electrodes one-to-one.

[0040] This configuration allows power units to be connected in series in a compact manner to form a power module, while ensuring the circuit performance and connectivity of the power module. Attached Figure Description

[0041] Figure 1 A schematic isometric view of a power unit provided for embodiments of this disclosure;

[0042] Figure 2 for Figure 1 A schematic top view of the main block of the medium power unit;

[0043] Figure 3 A schematic circuit topology diagram of the power unit provided for embodiments of this disclosure;

[0044] Figure 4 A schematic isometric view of a power unit provided for embodiments of this disclosure;

[0045] Figure 5 for Figure 4 A schematic top view of the main block of the medium power unit;

[0046] Figure 6A schematic diagram of the symmetrical structure of the first power unit and the second power unit provided for embodiments of this disclosure;

[0047] Figure 7 A schematic isometric view of a power module provided for embodiments of this disclosure;

[0048] Figure 8 A top view schematic diagram of a power module provided for an embodiment of this disclosure;

[0049] Figure 9 A schematic circuit topology diagram of a power module provided for embodiments of this disclosure;

[0050] Figure 10 A schematic diagram of the circuit features of a power module provided for an embodiment of this disclosure;

[0051] Figure 11 A schematic diagram of the power module provided in this embodiment of the disclosure;

[0052] Figure 12 A schematic cross-sectional view of a power module provided for an embodiment of this disclosure.

[0053] Explanation of reference numerals in the attached drawings: 1. Power unit; 2. Metal-clad insulating structure; 3. Base plate; 4. First electrode; 5. Second electrode; 6. Series connection structure; 7. Third metal layer; 8. Insulating plate; 9. Fourth metal layer; 11. Second welding layer; 12. Frame; 13. Encapsulation body; 10. First power unit; 20. Second power unit; 30. Third power unit; 40. Fourth power unit;

[0054] 100. First basic circuit unit; 101. First main switch transistor; 102. First auxiliary switch transistor; 103. First clamping capacitor; 104. First main gate signal terminal; 105. First main source signal terminal; 106. First auxiliary gate signal terminal; 107. First auxiliary source signal terminal; 108. First high-potential voltage signal terminal; 109. First low-potential voltage signal terminal; 200. Second basic circuit unit; 201. Second main switch transistor; 202. Second auxiliary switch transistor; 203. Second clamping capacitor; 204. Second main gate signal terminal; 205. Second main source signal terminal; 206. Second auxiliary gate signal terminal; 207. Second auxiliary source signal terminal; 208. Second high-potential voltage signal terminal; 209. Second low-potential voltage signal terminal; 300. Third basic circuit unit; 400. Fourth basic circuit unit; 500. Fifth basic circuit unit;

[0055] 1100 Basic circuit unit; 1200 Metal-clad substrate structure; 1210 Main block; 1220 First sub-block; 1230 Second sub-block; 1240 Third sub-block; 1250 Fourth sub-block; 1300 First metal layer; 1301 First power region; 1302 First low-voltage region; 1303 First high-voltage region; 1304 First high-voltage extension region; 1305 Power extension region; 1306 First main gate bar; 1307 First main source bar; 1308 First auxiliary source bar; 1309 First auxiliary... Gate bar; 1310, Connection area; 1311, Second power area; 1312, Second low voltage area; 1313, Second high voltage area; 1314, Second high voltage extension area; 1315, Low voltage extension area; 1315-1, Overlap area; 1316, Second main gate bar; 1317, Second main source bar; 1318, Second auxiliary source bar; 1319, Second auxiliary gate bar; 1400, Substrate; 1401, First main substrate; 1500, Second metal layer; 1600, First solder layer; 2401, Second main substrate; 2000, Power module. Detailed Implementation

[0056] To make the above-mentioned objects, features, and advantages of the embodiments of this disclosure more apparent and understandable, specific embodiments of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the embodiments of this disclosure. However, the embodiments of this disclosure can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the embodiments of this disclosure. Therefore, the embodiments of this disclosure are not limited to the specific embodiments disclosed below.

[0057] In the description of the embodiments of this disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing the embodiments of this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the embodiments of this disclosure.

[0058] In this disclosure, unless otherwise explicitly stated and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0059] Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. For example, a first basic circuit unit may also be referred to as a second basic circuit unit, and a second basic circuit unit may also be referred to as a first basic circuit unit. In the description of embodiments of this disclosure, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0060] In this disclosure, unless otherwise explicitly specified and limited, the terms "connected," "linked," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; a flexible connection or a rigid connection along at least one direction; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium, or a direct connection with an intermediate medium present; and they can also refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. The terms "installed," "set," "fixed," etc., can be broadly understood as connection. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0061] As used herein, the terms "layer" and "region" refer to a portion of material comprising a region of a certain thickness. A layer can extend horizontally, vertically, and / or along a conical surface. A layer can be a region of uniform or non-uniform continuous structure, the thickness of which perpendicular to the direction of extension may not exceed the thickness of the continuous structure. A layer can comprise multiple layers. The shapes of the various regions and layers in the accompanying drawings, and their relative sizes and positional relationships, are merely illustrative and may deviate from actual dimensions due to manufacturing tolerances or technical limitations, and the design may be adjusted to meet specific requirements.

[0062] See Figure 1 , Figure 1The power unit shown in this embodiment of the present disclosure includes a patterned first metal layer 1300. Figure 12 The power unit 1 includes two basic circuit units 1100. Exemplarily, the power unit 1 may include more basic circuit units 1100. These two basic circuit units 1100 may be a first basic circuit unit 100 and a second basic circuit unit 200. These basic circuit units 1100 may have the same circuit topology, but their actual circuit layouts may differ.

[0063] For example, the basic circuit unit 1100 is electrically connected to the metal-clad substrate structure 1200. The metal-clad substrate structure 1200 can be divided into relatively independent main blocks 1210, first sub-blocks 1220, second sub-blocks 1230, third sub-blocks 1240, and fourth sub-blocks 1250 along its extended surface, i.e., the XY plane. The basic circuit unit 1100 can be located in the main block 1210, and two basic circuit units 1100 can be arranged along a first direction parallel to the first metal layer 1300, such as the X-axis direction. The first metal layer 1300 can be copper foil, and the pattern of the first metal layer 1300 can be distributed in different blocks.

[0064] Combination Figure 2 As shown, Figure 2 The main block of an embodiment of this disclosure is shown. In some embodiments, the region in the first metal layer 1300 corresponding to a basic circuit unit 1100 includes a power region, a low-voltage region, a high-voltage region, and a high-voltage extension region. For example, the region in the first metal layer 1300 corresponding to the first basic circuit unit 100 includes a first power region 1301, a first low-voltage region 1302, a first high-voltage region 1303, and a first high-voltage extension region 1304; the region in the first metal layer 1300 corresponding to the second basic circuit unit 200 includes a second power region 1311, a second low-voltage region 1312, a second high-voltage region 1313, and a second high-voltage extension region 1314. The first power region 1301, the first low-voltage region 1302, and the first high-voltage region 1303 are arranged sequentially along the X-axis direction, and the second power region 1311, the second low-voltage region 1312, and the second high-voltage region 1313 are also arranged sequentially along the X-axis direction. The first high-voltage extension region 1304 is electrically connected to the first high-voltage region 1303 and can be a single integrated shape. The first high-voltage extension region 1304 can be located on one side of the first power region 1301 along the Y-axis direction perpendicular to the X-axis direction. The first high-voltage extension region 1304 can be referred to as the high-voltage extension region. The second high-voltage extension region 1314 is electrically connected to the second high-voltage region 1313 and can be a single integrated shape. The second high-voltage extension region 1314 can be located on one side of the second power region 1311 along the Y-axis direction perpendicular to the X-axis direction.

[0065] Figure 3 The circuit topology of the power unit provided in this disclosure embodiment is shown. For example... Figure 1 and Figure 3 As shown, the first basic circuit unit 1100 includes at least two first main switching transistors 101, a first auxiliary switching transistor 102, and a first clamping capacitor 103; the second basic circuit unit 200 includes at least two second main switching transistors 201, a second auxiliary switching transistor 202, and a second clamping capacitor 203. Each basic circuit unit 1100 may have a substantially identical circuit topology. Taking the first basic circuit unit 100 as an example, the first main switching transistors 101 may be connected in parallel to form a main branch; the first clamping capacitors 103 may be connected in parallel to each other and in series with the first auxiliary switching transistors 102 to form an active clamping branch. The main branch and the active clamping branch are connected in parallel.

[0066] The main and auxiliary switching transistors configured in the basic circuit unit 1100 can both be power electronic chips. In terms of chip structure, they include, but are not limited to, metal-oxide-semiconductor field-effect transistors (MOSFETs), insulated-gate bipolar transistors (IGBTs), and junction field-effect transistors (JFETs). The materials used in the chips are not limited to silicon (Si), but can also include various wide-bandgap semiconductor materials, such as silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga2O3), and diamond. In the circuit topology of power unit 1, to clearly show the series and parallel connections of the components in the circuit diagram, the body diodes or the configured anti-parallel freewheeling diodes in the power electronic chips are omitted.

[0067] like Figures 1 to 3As shown, at least two first main switching transistors 101 are located in the first power region 1301 and arranged side-by-side along the second direction. The drain D of the first main switching transistor 101 is electrically connected to the first power region 1301, and the source S of the first main switching transistor 101 is electrically connected to the first low-voltage region 1302. A first auxiliary switching transistor 102 is located in the first high-voltage extension region 1304. The drain D of the first auxiliary switching transistor 102 is electrically connected to the first high-voltage extension region 1304, and the source S of the first auxiliary switching transistor 102 is electrically connected to the drain D of the first main switching transistor 101. One end of the first clamping capacitor 103 is electrically connected to the first low-voltage region 1302, and the other end is electrically connected to the first high-voltage region 1303. The first power region 1301, the first high-voltage extension region 1304, and the first high-voltage region 1303 can be arranged clockwise. The first high-voltage extension region 1304 and the first high-voltage region 1303 can be used to form an integrated pattern, which is approximately "L" shaped.

[0068] At least two second main switching transistors 201 are located in the second power region 1311 and arranged in parallel along the second direction. The drain D of the second main switching transistor 201 is electrically connected to the second power region 1311, and the source S of the second main switching transistor 201 is electrically connected to the second low-voltage region 1312. A second auxiliary switching transistor 202 is located in the second high-voltage extension region 1314. The drain D of the second auxiliary switching transistor 202 is electrically connected to the second high-voltage extension region 1314, and the source S of the second auxiliary switching transistor 202 is electrically connected to the drain D of the second main switching transistor 201. One end of the second clamping capacitor 203 is electrically connected to the second low-voltage region 1312, and the other end is electrically connected to the second high-voltage region 1313. The second power region 1311, the second high-voltage extension region 1314, and the second high-voltage region 1313 can be arranged counterclockwise. The second high-voltage extension region 1314 and the second high-voltage region 1313 can be used to form an integrated pattern, which is approximately "L" shaped.

[0069] The high voltage region 1303 of the first basic circuit unit 100 is arranged opposite to the high voltage region 1313 of the second basic circuit unit 200; the first power region 1301 and the second power region 1311 are arranged opposite to each other.

[0070] The first metal layer 1300 further includes a connection region 1310 and a low-voltage extension region 1315. The connection region 1310 is electrically connected to the low-voltage region of the first basic circuit unit 100, i.e., the first low-voltage region 1302, and the connection region 1310 is also electrically connected to the power region of the second basic circuit unit 200, i.e., the second power region 1311. The first low-voltage region 1302, the connection region 1310, and the second power region 1311 can be used to form an integral pattern, and this pattern can have a "匚" shape. The low-voltage extension region 1315 is electrically connected to the low-voltage region of the second basic circuit unit 200, i.e., the second low-voltage region 1312, and extends to the side of the high-voltage region of the second basic circuit unit 200 that is away from the low-voltage region of the second basic circuit unit 200. The low-voltage extension region 1315 may include an overlapping region 1315-1, and the overlapping region 1315-1 can be located on the side of the second high-voltage extension region 1314 that is away from the second power region 1311 along the Y-axis direction. The second low-voltage region 1312 and the low-voltage extension region 1315 can form an integral pattern, and this pattern can generally have a "q" shape. The second high-voltage region 1313 can be embedded in the "q" shape. Exemplarily, as Figure 1 and Figure 2 shown, one end of some second clamping capacitors 203 is lapped on the second high-voltage region 1313, and the other end can be lapped on the low-voltage extension region 1315.

[0071] Exemplarily, within each basic circuit unit 1100, the connection region 1310 and the high-voltage extension region are located on opposite sides of the low-voltage region.

[0072] The power unit provided by the embodiment of the present disclosure realizes good reliability and good circuit performance through the pattern design of the first metal layer and the electrical connection of each power electronic component. The basic circuit units in the power unit are connected in series and the voltage division is balanced, and the power electronic components in the power unit can be conveniently expanded.

[0073] Exemplarily, the first metal layer 1300 includes a power extension region 1305. The power extension region 1305 is located on the side of the power region of the corresponding first basic circuit unit 100 that is away from the high-voltage extension region of the corresponding first basic circuit unit 100. The power extension region 1305 is electrically connected to the power region of the corresponding first basic circuit unit 100 and the first power region 1301. The power extension region 1305 can be used for electrical connection with external devices.

[0074] In some embodiments, the region of the first metal layer 1300 corresponding to one basic circuit unit 1100 further includes at least one terminal pattern. The terminal pattern is located on the side of the power region that is away from the low-voltage region and is electrically connected to the main switching transistor or electrically connected to the auxiliary switching transistor. The basic circuit unit 1100 further includes at least one inner signal terminal and at least one outer signal terminal. The inner signal terminal is electrically connected to the clamping capacitor, and the outer signal terminal is electrically connected to the terminal pattern.

[0075] For example, such as Figure 1 and Figure 2 As shown, the region in the first metal layer 1300 corresponding to a basic circuit unit 1100 also includes a main source bar, a main gate bar, an auxiliary source bar, and an auxiliary gate bar. For example, the first metal layer 1300 includes a first main gate bar 1306, a first main source bar 1307, a first auxiliary source bar 1308, and a first auxiliary gate bar 1309 corresponding to the first basic circuit unit 100. The first main source bar 1307 and the first main gate bar 1306 are located on the side of the first power region 1301 opposite to the first low-voltage region 1302, and the first auxiliary source bar 1308 and the first auxiliary gate bar 1309 are located on the side of the first high-voltage extension region 1304 opposite to the first high-voltage region 1303 along the X-axis direction. The first metal layer 1300 includes a second main gate bar 1316, a second main source bar 1317, a second auxiliary source bar 1318, and a second auxiliary gate bar 1319 corresponding to the second basic circuit unit 200. These patterns may be substantially symmetrical to the patterns corresponding to the first basic circuit unit 100. In some embodiments, for each basic circuit unit 1100, the main source bar is located between the main gate bar and the power region, and the auxiliary source bar is located between the auxiliary gate bar and the high-voltage extension region. These patterns may be located in the main block 1210.

[0076] refer to Figure 1 The external signal terminals of the first basic circuit unit 100 include: a first main gate signal terminal 104 electrically connected to the gate G of the first main switch 101 via a first main gate bar 1306; a first main source signal terminal 105 electrically connected to the source S of the first main switch 101 via a first main source bar 1307; a first auxiliary gate signal terminal 106 electrically connected to the gate G of the first auxiliary switch 102 via a first auxiliary gate bar 1309; and a first auxiliary source signal terminal 107 electrically connected to the source S of the first auxiliary switch 102 via a first auxiliary source bar 1308. The first main source signal terminal 105 and the first main gate signal terminal 104 are located in the first sub-block 1220; the first auxiliary gate signal terminal 106 and the first auxiliary source signal terminal 107 are located in the second sub-block 1230.

[0077] The external signal terminals of the second basic circuit unit 200 include a second main gate signal terminal 204 electrically connected to the gate G of the second main switch 201 via a second main gate bar 1316, a second main source signal terminal 205 electrically connected to the source S of the second main switch 201 via a second main source bar 1317, a second auxiliary gate signal terminal 206 electrically connected to the gate G of the second auxiliary switch 202 via a second auxiliary gate bar 1319, and a second auxiliary source signal terminal 207 electrically connected to the source S of the second auxiliary switch 202 via a second auxiliary source bar 1318. The second main gate signal terminal 204 and the second main source signal terminal 205 are located in the third sub-block 1240; the second auxiliary gate signal terminal 206 and the second auxiliary source signal terminal 207 are located in the fourth sub-block 1250.

[0078] For example, in the first basic circuit unit 100, the first main source signal terminal 105, the first main gate signal terminal 104, the first auxiliary gate signal terminal 106, and the first auxiliary source signal terminal 107 are arranged sequentially in a row along the Y-axis direction. In the second basic circuit unit 200, the second main source signal terminal 205, the second main gate signal terminal 204, the second auxiliary gate signal terminal 206, and the second auxiliary source signal terminal 207 are arranged sequentially in a row along the second direction. This arrangement facilitates the electrical connection between the power unit 1 and the signal detection circuit.

[0079] For example, the inner signal terminals of the first basic circuit unit 100 include a first high-potential voltage signal terminal 108 located in the first high-voltage region 1303 and a first low-potential voltage signal terminal 109 located in the connection region 1310. The inner signal terminals of the second basic circuit unit 200 include a second high-potential voltage signal terminal 208 located in the second high-voltage extension region 1314 and a second low-potential voltage signal terminal 209 located in the low-voltage extension region 1315.

[0080] For example, in the first basic circuit unit 100, along the Y-axis direction, the inner signal terminal is located on the side opposite to the first auxiliary switch 102 relative to the first main switch 101; in the second basic circuit unit 200, along the Y-axis direction, the inner signal terminal is located on the same side of the second auxiliary switch 202 relative to the second main switch 201.

[0081] For example, power unit 1 may also include a freewheeling diode (not shown). For instance, within basic circuit unit 1100, a first freewheeling diode connected in anti-parallel to the main switch, or a second freewheeling diode connected in anti-parallel to the auxiliary switch, may be included. The cathode of the first freewheeling diode may be connected to the drain D of the main switch, and the anode of the first freewheeling diode may be connected to the source S of the main switch. In other words, the first freewheeling diode may be connected in reverse parallel to the main branch. The cathode of the second freewheeling diode may be connected to the drain D of the auxiliary switch, and the anode of the second freewheeling diode may be connected to the source S of the auxiliary switch.

[0082] Figure 4 This illustration shows a power unit provided in an embodiment of the present disclosure. The power unit 1 provided in this embodiment includes a patterned first metal layer 1300. Figure 12 The power unit 1 includes two basic circuit units 1100. Exemplarily, the power unit 1 may include more basic circuit units 1100. These two basic circuit units 1100 may be a first basic circuit unit 100 and a second basic circuit unit 200. These basic circuit units 1100 may have the same circuit topology, but their actual circuit layouts may differ.

[0083] In some embodiments, the region in the first metal layer 1300 corresponding to a basic circuit unit 1100 includes a power region, a low-voltage region, a high-voltage region, and a high-voltage extension region. The first power region 1301, the first low-voltage region 1302, and the first high-voltage region 1303 are arranged sequentially along the X-axis direction, and the second power region 1311, the second low-voltage region 1312, and the second high-voltage region 1313 are also arranged sequentially along the X-axis direction. The first high-voltage extension region 1304 is electrically connected to the first high-voltage region 1303 and can be an integral part of the same shape. The first high-voltage extension region 1304 can be located on one side of the first power region 1301 along the Y-axis direction perpendicular to the X-axis direction. The first high-voltage extension region 1304 can be referred to as the high-voltage extension region. The second high-voltage extension region 1314 is electrically connected to the second high-voltage region 1313 and can be an integral part of the same shape. The second high-voltage extension region 1314 can be located on one side of the second power region 1311 along the Y-axis direction perpendicular to the X-axis direction.

[0084] Figure 5The main block of the power unit provided in this embodiment is shown. The first power region 1301, the first high-voltage extension region 1304, and the first high-voltage region 1303 may be arranged counterclockwise. The first high-voltage extension region 1304 and the first high-voltage region 1303 can be used to form an integrated pattern, which is generally "L"-shaped. The second power region 1311, the second high-voltage extension region 1314, and the second high-voltage region 1313 may be arranged clockwise. The second high-voltage extension region 1314 and the second high-voltage region 1313 can be used to form an integrated pattern, which is generally "L"-shaped. The connection region 1310 is electrically connected to the low-voltage region 1302 of the first basic circuit unit 100, and is also electrically connected to the power region 1311 of the second basic circuit unit 200. The first low-voltage region 1302, the connection region 1310, and the second power region 1311 can be used to form an integrated pattern, which may be "U"-shaped. The second low-pressure region 1312 and the low-pressure extension region 1315 can form an integral shape, which can be approximately "d"-shaped. The second high-pressure region 1313 can be embedded in the "d" shape. For example, as... Figure 4 and Figure 5 As shown, one end of some second clamping capacitors 203 is connected to the second high voltage region 1313, and the other end can be connected to the low voltage extension region 1315.

[0085] The high-voltage region 1303 of the first basic circuit unit 100 and the high-voltage region 1313 of the second basic circuit unit 200 are arranged opposite each other; the first power region 1301 and the second power region 1311 are arranged opposite each other. For example, in each basic circuit unit 1100, the connection region 1310 and the high-voltage extension region are located on opposite sides of the low-voltage region.

[0086] Figure 4 The power unit shown is Figure 1 The power unit shown may have a mirror-symmetric structure; approximations will not be elaborated further. In summary, within each basic circuit unit 1100, at least two main switching transistors are located in the power region and arranged side-by-side along the second direction. The drain of the main switching transistors is electrically connected to the power region, and the source of the main switching transistors is electrically connected to the low-voltage region. An auxiliary switching transistor is located in the high-voltage extension region, with its drain electrically connected to the high-voltage extension region and its source electrically connected to the drain of the main switching transistors. One end of a clamping capacitor is electrically connected to the low-voltage region, and the other end is electrically connected to the high-voltage region. The clamping capacitor can be, for example, a surface-mount capacitor, with one end located in the low-voltage region and the other end in the high-voltage region.

[0087] Figure 6The symmetrical structure of the first power unit and the second power unit provided in this embodiment is shown. Exemplarily, along the X-axis direction, with the surface parallel to the YZ plane as a mirror, the first power unit 10 and the second power unit 20 are disposed opposite to each other, and the patterned copper foil on the first main substrate 1401 and the patterned copper foil on the second main substrate 2401 can have a mirror-symmetrical structure.

[0088] refer to Figure 7 and Figure 8 , Figure 7 A power module provided in an embodiment of this disclosure is shown. Figure 8 for Figure 7 A top view. The power module 2000 provided in this embodiment includes a first power unit 10 and a second power unit 20 alternately arranged and connected in series, the alternation direction being the Y-axis direction. At least one of the first power unit 10 and the second power unit 20 is the aforementioned power unit 1. For example, the first power unit 10 may be adopted according to... Figure 1 In the provided embodiments, the second power unit 20 may be adopted according to Figure 4 The provided examples.

[0089] refer to Figure 7 and Figure 8 The first power unit 10 includes a first basic circuit unit 100 and a second basic circuit unit 200. The second power unit 20 includes a third basic circuit unit 300 and a fourth basic circuit unit 400. For the second power unit 20, the third basic circuit unit 300 can be referred to as the first basic circuit unit, and the fourth basic circuit unit 400 can be referred to as the second basic circuit unit.

[0090] For example, the power module 2000 includes a series connection structure 6. The second basic circuit unit 200 and the third basic circuit unit 300 are electrically connected via the series connection structure 6. One end of the series connection structure 6 can be connected to the low-voltage extension region or connection region of the second basic circuit unit 200, and the other end can be connected to the power extension region of the third basic circuit unit 300. The series connection structure 6 connects to two adjacent power units 1; for example, the second power unit 20 and the third power unit 30 are also connected by one series connection structure 6, and the third power unit 30 and the fourth power unit 40 can be connected by another series connection structure 6. In two adjacent power units 1, the low-voltage extension region of one is electrically connected to the power extension region of the other via the series connection structure 6.

[0091] For example, the power module 2000 includes two electrodes. Two power units 1 located at both ends in series are electrically connected to these two electrodes one-to-one. The number of power units 1 can be odd or even. For example, the first electrode 4 can be electrically connected to the first power unit 10, for example, to the power extension region of the first power unit 10; the second electrode 5 can be electrically connected to the fifth basic circuit unit 500 of the fourth power unit 40, for example, to the low-voltage extension region.

[0092] Figure 9 The circuit topology of a power module provided in this embodiment is illustrated. The withstand voltage of the power module 2000 is the product of the withstand voltage of the basic circuit unit 1100 and the number of basic circuit units 1100. Exemplarily, in the power module 2000, the number of power units 1 connected in series is N, where N is a positive integer greater than or equal to 2. Each power unit 1 may include two basic circuit units 1100, and the number of basic circuit units 1100 may be 2N. The withstand voltage of the power module 2000 is N times the withstand voltage of the power unit 1 and 2N times the withstand voltage of the basic circuit unit 1100.

[0093] Figure 10 The layout features of a power module provided in this embodiment are shown. The power module 2000 may have a long axis parallel to the Y-axis direction, which may pass through the centroid of the power module 2000. A first electrode 4 may serve as a power electrode DC+, and a second electrode 5 may serve as a power electrode DC-. The main power branches of the power module 2000 include the main branches of each power unit 1 and a series connection structure 6, with the direction of the main branches within each power unit 1 generally along the X-axis direction. The main power branches generally have a square wave shape, which may unfold along the long axis. The active clamping branch of each power unit 1 may follow the square wave direction. Furthermore, inner sampling terminals are located near the long axis and are periodically distributed along the Y-axis direction.

[0094] Figure 11 A power module provided in an embodiment of this disclosure is shown. Figure 12 A cross-sectional view of a power module provided in an embodiment of this disclosure is shown. In an exemplary embodiment, power unit 1 includes a metal-clad substrate structure 1200. The metal-clad substrate structure 1200 includes a second metal layer 1500, a substrate 1400, and a first metal layer 1300 stacked sequentially. The substrate 1400 includes a first substrate, a second substrate, and a third substrate arranged sequentially and spaced apart from each other along the X-axis direction, and may also include other substrates arranged side by side. The second substrate may belong to the main block 1210. The second substrate may be referred to as the main substrate.

[0095] For example, the power module 2000 further includes a metal-clad insulating structure 2 and at least two first solder layers 1600. These first solder layers 1600 are arranged sequentially along the metal-clad insulating structure 2. The metal-clad substrate structure 1200 of the power unit 1 is fixed to the metal-clad insulating structure 2 via corresponding first solder layers 1600. The metal-clad insulating structure 2 may include a stacked third metal layer 7, an insulating plate 8, and a fourth metal layer 9. The third metal layer 7 may be divided into multiple parts, each corresponding to a power unit 1. When the power unit 1 includes, for example, five blocks, the third metal layer 7 may include a metal portion corresponding to each block.

[0096] Exemplarily, the power module 2000 also includes a second welding layer 11, a base plate 3, and a frame 12. The base plate 3 is located on the side of the metal-clad insulating structure 2 opposite to the first welding layer 1600 and is fixedly connected to the metal-clad insulating structure 2 through the second welding layer 11. Each of the four corners of the metal-clad insulating structure 2 can be formed with a notch to expose the base plate 3 along the stacking direction. The frame 12 surrounds the power unit 1 and is fixedly connected to the base plate 3 through the notch. The frame 12 can be made of plastic. The first electrode 4 and the second electrode 5 can be fixedly fitted to the frame 12, or the first electrode 4 and the second electrode 5 can be pre-fixed by the frame 12 during manufacturing to eliminate the need for a fixture in the electrode welding step.

[0097] like Figure 12 As shown, a frame 12 can be used to fill the space with potting compound, which substantially covers each power unit 1 and solidifies into a package 13. Each signal terminal and electrode can partially extend outside the package 13. The package 13 protects the power unit 1 and contributes to insulation. Exemplarily, the dimension of the insulating plate 8 of the metal-coated insulating structure 2 along the stacking direction is greater than or equal to the quotient obtained by dividing the withstand voltage of the power module 2000 by the breakdown field strength of the material of the insulating plate 8. This ensures the safety of the outer side of the base plate 3.

[0098] The metal-coated insulation structure 2 can be a single, integral structure. For example, Figure 12 The diagram shows the main block 1210 of each power unit 1. This main block 1210 includes a second substrate in the substrate 1400 and metal foils located on both sides of the second substrate. The upper metal foil includes patterns not shown; for example, the first power unit 10 includes patterns for welding to the series connection structure 6, and patterns for welding to the first electrode 4. The lower metal foil may have a rectangular outer contour, which is smaller than the outer contour of the second substrate.

[0099] In the first power unit 10, the second metal layer 1500 includes a lower metal foil belonging to the main block 1210. The lower metal foil is welded to a first metal portion of the third metal layer 7, and the projection of the first metal portion along the Z-axis is greater than or equal to the projection of the lower metal foil, while the projection of the first metal portion along the Z-axis is smaller than the projection of the second substrate. This arrangement allows the first metal portion to cover the lower metal foil, ensuring accurate welding of the main block 1210, guaranteeing the electric field distribution within the power module 2000, and contributing to improved safety and reliability.

[0100] For example, a small-sized block of power unit 1 includes a small metal foil, a first substrate, and a first pair of terminal patterns stacked sequentially. The small metal foil is soldered to a second metal portion of the third metal layer 7. The projection of the second metal portion along the Z-axis is greater than or equal to the projection of the small metal foil, and smaller than the projection of the first substrate.

[0101] The technical features of the above-disclosed embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0102] The embodiments disclosed above merely illustrate several implementation methods of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of patent protection for the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept, and these all fall within the scope of patent protection claimed by the present invention. Therefore, the scope of patent protection for the present invention should be determined by the appended claims.

Claims

1. A power unit, characterized in that, include: A patterned first metal layer and two basic circuit units, the two basic circuit units being arranged along a first direction parallel to the first metal layer; The region in the first metal layer corresponding to one of the basic circuit units includes a power region, a low-voltage region, a high-voltage region, and a high-voltage extension region. The power region, the low-voltage region, and the high-voltage region are arranged sequentially along the first direction. The high-voltage extension region is electrically connected to the high-voltage region. The high-voltage extension region is located on one side of the power region along a second direction perpendicular to the first direction. The basic circuit unit includes: At least two main switching transistors are located in the power region and arranged in parallel along the second direction, with the drain of the main switching transistors electrically connected to the power region and the source of the main switching transistors electrically connected to the low-voltage region. An auxiliary switching transistor is located in the high-voltage extension region. The drain of the auxiliary switching transistor is electrically connected to the high-voltage extension region, and the source of the auxiliary switching transistor is electrically connected to the drain of the main switching transistor. A clamping capacitor, one end of which is electrically connected to the low-voltage region and the other end of which is electrically connected to the high-voltage region; The two basic circuit units include a first basic circuit unit and a second basic circuit unit, wherein the high voltage region of the first basic circuit unit and the high voltage region of the second basic circuit unit are arranged opposite to each other. The first metal layer includes a connection region and a low-voltage extension region. The connection region is electrically connected to the low-voltage region of the first basic circuit unit and is also electrically connected to the power region of the second basic circuit unit. The low-voltage extension region is electrically connected to the low-voltage region of the second basic circuit unit and extends to the side of the high-voltage region of the second basic circuit unit away from the low-voltage region of the second basic circuit unit.

2. The power unit according to claim 1, wherein, The connection area and the high-voltage extension area are located on opposite sides of the low-voltage area, and the low-voltage extension area extends to the side of the high-voltage extension area of ​​the second basic circuit unit away from the power area of ​​the second basic circuit unit. The first metal layer includes a power extension region located on the side of the power region of the first basic circuit unit away from the high voltage extension region of the first basic circuit unit, and the power extension region is electrically connected to the power region of the first basic circuit unit.

3. The power unit according to claim 1, wherein, The area in the first metal layer corresponding to one of the basic circuit units further includes at least one terminal pattern, the terminal pattern being located on the side of the power region away from the low voltage region, and the terminal pattern being electrically connected to the main switch or electrically connected to the auxiliary switch; The basic circuit unit further includes at least one inner signal terminal and at least one outer signal terminal, wherein the inner signal terminal is electrically connected to the clamping capacitor and the outer signal terminal is electrically connected to the terminal pattern.

4. The power unit according to claim 3, wherein, The region in the first metal layer corresponding to one of the basic circuit units further includes a main source bar, a main gate bar, an auxiliary source bar, and an auxiliary gate bar. The main source bar and the main gate bar are located on the side of the power region away from the low voltage region, and the auxiliary source bar and the auxiliary gate bar are located on the side of the high voltage extension region away from the high voltage region along the first direction. The at least one external signal terminal includes: a main gate signal terminal electrically connected to the gate of the main switch transistor via the main gate bar; a main source signal terminal electrically connected to the source of the main switch transistor via the main source bar; an auxiliary gate signal terminal electrically connected to the gate of the auxiliary switch transistor via the auxiliary gate bar; and an auxiliary source signal terminal electrically connected to the source of the auxiliary switch transistor via the auxiliary source bar.

5. The power unit according to claim 4, wherein, The main source electrode bar is located between the main gate electrode bar and the power region, and the auxiliary source electrode bar is located between the auxiliary gate electrode bar and the high voltage extension region; In the first basic circuit unit, the main source signal terminal, the main gate signal terminal, the auxiliary gate signal terminal, and the auxiliary source signal terminal are arranged in a row along the second direction; In the second basic circuit unit, the main source signal terminal, the main gate signal terminal, the auxiliary gate signal terminal, and the auxiliary source signal terminal are arranged in sequence along the second direction and lined up in a row.

6. The power unit according to claim 3, wherein, In the first basic circuit unit, the inner signal terminal is located on the side opposite to the auxiliary switch relative to the main switch; in the second basic circuit unit, the inner signal terminal is located on the same side as the auxiliary switch relative to the main switch.

7. The power unit according to claim 1, wherein, The power unit includes a metal-clad substrate structure, which includes a second metal layer, a substrate, and a first metal layer stacked sequentially. The substrate includes a first substrate, a second substrate, and a third substrate that are sequentially arranged and separated from each other along the first direction. The second substrate is provided with the power region, low voltage region, high voltage region and high voltage extension region of the first basic circuit unit, the power region, low voltage region, high voltage region and high voltage extension region of the second basic circuit unit, the connection region and the low voltage extension region; The high-voltage zone and the high-voltage extension zone are an integral graphic; The low-voltage region of the first substrate circuit unit, the connection region, and the power region of the second basic circuit unit are integrally formed, and the low-voltage region of the second basic circuit unit and the low-voltage extension region are integrally formed.

8. A power module, characterized in that, include: A first power unit and a second power unit are alternately arranged and connected in series, wherein at least one of the first power unit and the second power unit is a power unit according to any one of claims 1 to 7, and the direction of the alternation is the second direction.

9. The power module according to claim 8, wherein, The first power unit and the second power unit have a symmetrical structure with the vertical plane in the first direction as a mirror.

10. The power module according to claim 8, wherein, It also includes a metal-clad insulating structure, at least two first welding layers, a second welding layer, a base plate, and a frame. The at least two first welding layers are arranged sequentially along the metal-clad insulating structure. The metal-clad substrate structure of the power unit is fixed to the metal-clad insulating structure through the corresponding first welding layer. The base plate is located on the side of the metal-clad insulating structure away from the first welding layer and is fixedly connected to the metal-clad insulating structure through the second welding layer. The four corners of the metal-clad insulating structure are formed with notches to expose the base plate along the stacking direction. The frame surrounds the at least two first welding layers and is fixedly connected to the base plate through the notches. The dimension of the insulating plate of the metal-clad insulating structure along the stacking direction is greater than or equal to the quotient obtained by dividing the withstand voltage of the power module by the breakdown field strength of the insulating plate material.

11. The power module according to claim 8, wherein, It also includes at least one of a first freewheeling diode and a second freewheeling diode, wherein the cathode of the first freewheeling diode is electrically connected to the drain of the main switching transistor, and the anode of the first freewheeling diode is electrically connected to the source of the main switching transistor; the cathode of the second freewheeling diode is electrically connected to the drain of the auxiliary switching transistor, and the anode of the second freewheeling diode is electrically connected to the source of the auxiliary switching transistor; the withstand voltage of the power module is the product of the withstand voltage of the basic circuit unit and the number of the basic circuit units.

12. The power module according to claim 8, wherein, It also includes at least one series connection structure and two electrodes, wherein the series connection structure is connected to two adjacent power units, and in the two adjacent power units, the low voltage extension region of one is electrically connected to the power extension region of the other through the series connection structure. The two power units located at both ends in series are electrically connected to the two electrodes in a one-to-one correspondence.

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