Power unit, power module

Abstract

The present disclosure relates to a power unit, a power module. The power unit comprises: a first metal layer comprising: a first mounting area in which a main switch tube is mounted; a first connecting area protruding from one side of the first mounting area; a second connecting area located on one side of the first mounting area and electrically connected to the source electrode of the main switch tube; a second mounting area located on one side of the first connecting area away from the first mounting area; and a third connecting area located on one side of the second connecting area away from the first mounting area and electrically connected to the second mounting area; an auxiliary switch tube mounted on the second mounting area, the source electrode of which is electrically connected to the first connecting area; and a clamping capacitor, one end of which is located in the second connecting area and the other end of which is located in the third connecting area. The power unit can achieve high reliability. The power module formed by connecting the power units in series greatly simplifies the expansion of voltage and current levels and improves the internal electric field distribution, the high-density integrated design reduces the stray inductance of the power module, and the series main switch tube realizes fast and reliable voltage sharing.

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 2.3-2.5 power 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 increasing the withstand voltage of a device by a factor of 5 (e.g., from 1200V to 6000V) will increase the device's losses by more than 25 times.

[0003] For traditional silicon-based devices, significantly increasing the voltage rating relies solely on bipolar device structure design. However, the high switching losses of bipolar devices limit their application. 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 representative of third-generation 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 at a reasonable price. However, due to limitations in SiC materials and chip manufacturing technology, low-cost, reliable, high-voltage SiC devices remain a distant prospect. Therefore, using series-connected, low-loss SiC devices to achieve high-voltage power module solutions 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: the multilevel converter scheme and the power device series scheme. Cascaded H-bridge multilevel converters (CHBs) and modular multilevel converters (MMCs) are characterized by their modular structure, high efficiency, and high reliability, and have been applied in many medium-to-high power applications. However, multilevel converter schemes typically require the use of large-sized passive components. For example, CHBs require a large phase-shifting transformer, while capacitors account for approximately 70% of the size of submodules in MMCs. 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. Series connection of power electronic devices improves the voltage withstand rating and increases the output power of the power conversion system. Its advantages over multi-level technology include a smaller system size, fewer passive components, and a simpler circuit topology. However, due to differences in the electrical performance parameters of power electronic devices or external circuit conditions, such as 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 balance 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] Current research on active clamping is based on discrete devices or standardized industry modules. Series schemes based on discrete devices 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 series schemes based on standardized commercial modules address the high-power requirements of medium- and high-voltage applications, the mismatch between the power loop circuit topology of commercial modules and the overall architecture of power conversion systems employing active clamping control strategies leads to several limitations. These limitations include inconvenient expansion of voltage and current levels in 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. Summary of the Invention

[0007] Therefore, it is necessary to provide a power unit based on an active clamping circuit topology and a power module based on an active clamping circuit topology to address at least one of the above problems.

[0008] This disclosure provides a power unit based on an active clamping circuit topology. The power unit includes: a main switch transistor; a patterned first metal layer, the first metal layer including: a first mounting region on which the main switch transistor is mounted and electrically connected to the drain of the main switch transistor; a first connection region protruding from one side of the first mounting region along a first direction and electrically connected to the first mounting region; a second connection region located on one side of the first mounting region along the first direction and electrically connected to the source of the main switch transistor; a second mounting region located on the side of the first connection region away from the first mounting region along the first direction; and a third connection region located on the side of the second connection region away from the first mounting region along the first direction and electrically connected to the second mounting region; an auxiliary switch transistor mounted in the second mounting region, the drain of the auxiliary switch transistor electrically connected to the second mounting region, and the source of the auxiliary switch transistor electrically connected to the first connection region; and a clamping capacitor, the first end of the clamping capacitor being electrically connected to ground in the second connection region, and the second end of the clamping capacitor being electrically connected to ground in the third connection region.

[0009] The high-electric-field region and low-electric-field region within the power unit provided in this disclosure are designed to be distinct, thereby improving the electrical reliability of the power unit. The structural design within the power unit ensures the distribution of various components and the circuit topology, with the components arranged relatively closely and the power unit size being small.

[0010] In some embodiments, the main switch is used to form a power branch, and the auxiliary switch and clamping capacitor are used to form a clamping branch; the first metal layer also includes a first pair of terminal patterns and a second pair of terminal patterns; the power unit also includes a main gate signal terminal, a main source signal terminal, an auxiliary gate signal terminal, an auxiliary source signal terminal, a low-voltage sampling terminal, and a high-voltage sampling terminal; the main gate signal terminal and the main source signal terminal are located on the side of the power branch away from the clamping branch and are electrically connected to the ground in the first pair of terminal patterns, the main gate signal terminal is electrically connected to the gate of the main switch, and the main source signal terminal is electrically connected to the source of the main switch; the auxiliary gate signal terminal and the auxiliary source signal terminal are located on the side of the clamping branch away from the power branch and are electrically connected to the ground in the second pair of terminal patterns, the auxiliary gate signal terminal is electrically connected to the gate of the auxiliary switch, and the auxiliary source signal terminal is electrically connected to the source of the auxiliary switch; the low-voltage sampling terminal is electrically connected to the ground in the second connection area, and the high-voltage sampling terminal is electrically connected to the ground in the third connection area.

[0011] The high-electric-field region and low-electric-field region within the power unit provided in this disclosure are designed to be distinct, thereby improving the reliability of the power unit. This separation ensures the proper distribution of each terminal and guarantees compact electrical connections and high-density integration with external control and sampling circuits.

[0012] In some embodiments, the main gate signal terminal and the main source signal terminal are arranged perpendicular to the first direction, and the auxiliary gate signal terminal and the auxiliary source signal terminal are arranged perpendicular to the first direction; the power branch includes at least two main switching transistors connected in parallel, and the arrangement of the at least two main switching transistors is perpendicular to the first direction; the clamping branch includes at least two clamping capacitors connected in parallel, the arrangement of the auxiliary switching transistors and the clamping capacitors is perpendicular to the first direction, the low-voltage end of the clamping capacitor faces the power branch, and the high-voltage end of the clamping capacitor faces away from the power branch.

[0013] With this configuration, the power unit has a compact structure and controlled electric field distribution. The parasitic inductance of the power unit is smaller, and the electric field distribution pattern of the clamping branch is better.

[0014] In some embodiments, the first metal layer 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 first mounting region away from the second connection region, the source of the main switch is electrically connected to the main source signal terminal through the main source bar, and the gate of the main switch is electrically connected to the main gate signal terminal through the main gate bar; the auxiliary source bar and the auxiliary gate bar are located on the side of the second mounting region away from the first connection region, the source of the auxiliary switch is electrically connected to the auxiliary source signal terminal through the auxiliary source bar, and the gate of the auxiliary switch is electrically connected to the auxiliary gate signal terminal through the auxiliary gate bar.

[0015] This configuration helps to expand the number of main switching transistors and improve the current rating of the power unit. The design of separating the input and output paths of the switching transistors reduces the negative feedback of the common source inductor during switching transients, which helps to improve the switching speed of the power unit. In addition, it helps to isolate the power branch from the clamping branch and isolates the low electric field area outside the power unit, thus optimizing the electric field distribution of the power unit.

[0016] 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; a first mounting area and a first connection area are used to form an integrated power pattern; a second connection area is used to form an integrated low-voltage pattern; and a second mounting area and a third connection area are used to form an integrated high-voltage pattern.

[0017] This configuration results in a compact layout for the power unit, along with good structural strength and long-term reliability.

[0018] In some embodiments, the substrate includes a first substrate, a second substrate, and a third substrate that are sequentially disposed and spaced apart from each other along a first direction; the power pattern, the low-voltage pattern, and the high-voltage pattern are all located on the second substrate.

[0019] This design improves the structural strength of the power unit and ensures its reliability. Furthermore, it reduces manufacturing costs.

[0020] In some embodiments, the first metal layer has a central position located between the main switch and the auxiliary switch, the power pattern includes a fourth connection region located at the central position, and the low-voltage pattern includes a fifth connection region located at the central position.

[0021] This configuration allows the power unit to be electrically connected to external devices along the central axis and at the central axis position, which helps to control the electric field distribution and achieve a compact layout.

[0022] In another aspect, this disclosure also provides a power module comprising: at least two of the aforementioned power units connected in series, the power units being arranged sequentially along a second direction perpendicular to the first direction.

[0023] The power module provided in this disclosure expands voltage and current levels through series-connected power units and exhibits good electrical reliability. This power module features a high-density structure and low parasitic inductance, enabling rapid and reliable voltage equalization among the power units. It can utilize low-voltage power electronic devices for high-voltage, high-current power conversion applications, offering advantages such as low cost and low loss. Furthermore, the overall main power circuit can be arranged in a straight line, reducing its length and thus lowering the parasitic inductance of the main power circuit, which also facilitates rapid and reliable voltage equalization among the multiple series-connected main switches.

[0024] 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.

[0025] This power module has good insulation and safety, and the structural strength of the power module can be increased by setting a metal-clad insulation structure to ensure reliable circuit connection.

[0026] In some embodiments, the metal-clad insulating structure includes a third metal layer, an insulating plate, and a fourth metal layer stacked sequentially in a direction away from the power unit. The projection of each metal portion of the third metal layer along the stacking direction covers the lower metal foil of the metal-clad substrate structure and is covered by the projection of the substrate of the metal-clad substrate structure.

[0027] This design ensures the overall insulation performance of the power module when operating under high voltage conditions, and ensures accurate positioning of each metal-clad substrate structure on the third metal layer, facilitating manufacturing and improving the manufacturing yield of the power module.

[0028] 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.

[0029] By controlling the thickness of the insulation board, the insulation performance of the power module can be ensured, the stable operation of each component can be guaranteed, and the power module can be made safe and reliable.

[0030] 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.

[0031] 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.

[0032] 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 power unit and the number of power units.

[0033] This configuration optimizes the circuit performance of the power module and ensures its effectiveness in high-voltage environments.

[0034] In some embodiments, the power module further includes at least one series connection structure and two electrodes. The connection structure overlaps two adjacent power units. In the two adjacent power units, the fourth connection area of ​​one is electrically connected to the fifth connection area of ​​the other through the series connection structure. The two power units located at both ends along the series sequence are electrically connected to the two electrodes one-to-one.

[0035] With this configuration, the power module has a compact structure, is easy to expand, and has a good electric field distribution, ensuring reliable series connection of power units and convenient and reliable electrical connection with external devices. Attached Figure Description

[0036] Figure 1 A schematic diagram of the circuit topology of the power unit provided in this embodiment of the disclosure;

[0037] Figure 2 A schematic isometric view of a power unit provided for embodiments of this disclosure;

[0038] Figure 3 A schematic top view of a power unit provided for an embodiment of this disclosure;

[0039] Figure 4 A schematic diagram of the first block structure of the power unit provided in this embodiment of the present disclosure;

[0040] Figure 5 A schematic isometric view of a power module provided for embodiments of this disclosure;

[0041] Figure 6 A schematic top view of a power module provided for an embodiment of this disclosure;

[0042] Figure 7 A schematic diagram of the circuit topology of the power module provided in this embodiment of the disclosure;

[0043] Figure 8 A schematic diagram illustrating the layout features of a power module provided in an embodiment of this disclosure;

[0044] Figure 9 A schematic diagram of the metal-clad insulation structure of the power module provided in this embodiment of the disclosure;

[0045] Figure 10 A schematic isometric view of a power module provided for embodiments of this disclosure;

[0046] Figure 11 A schematic cross-sectional view of a power module provided for an embodiment of this disclosure.

[0047] Explanation of reference numerals in the attached diagram: 1. Power branch; 10. Main switch transistor; 2. Clamping branch; 20. Clamping capacitor; 3. Auxiliary switch transistor; 4. Main gate signal terminal; 5. Main source signal terminal; 6. Auxiliary gate signal terminal; 7. Auxiliary source signal terminal; 8. High-voltage sampling terminal; 9. Low-voltage sampling terminal; 11. First substrate; 12. Second substrate; 13. Third substrate; 14. First metal layer; 15. First pair of terminals pattern; 16. Power pattern; 161. First Mounting area; 162, First connection area; 163, Fourth connection area; 17, Low-voltage pattern; 171, Second connection area; 172, Fifth connection area; 173, Sixth connection area; 18, High-voltage pattern; 181, Second mounting area; 182, Third connection area; 183, Seventh connection area; 19, Second terminal pattern; 21, Main source bar; 22, Main gate bar; 23, Secondary gate bar; 24, Secondary source bar; 25, Second metal layer; 26, First solder layer;

[0048] 30. Metal-clad insulating structure; 301. Third metal layer; 3011. First metal part; 3012. Second metal part; 302. Insulating plate; 303. Fourth metal layer; 31. Base plate; 311. Second welding layer; 32. First electrode; 33. Second electrode; 34. Series connection structure; 35. Frame; 36. Encapsulation body; 37. Cover;

[0049] 100, Power Unit; 101, First Power Unit; 102, Second Power Unit; 103, Third Power Unit; 200, Power Module. Detailed Implementation

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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 power unit may also be referred to as a second power unit, and a second power unit may also be referred to as a first power unit; a first connection region may be referred to as a second connection region, and a second connection region may be referred to as a first connection region. In the description of embodiments of this disclosure, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0054] 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.

[0055] 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, zones, 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.

[0056] See Figure 1 , Figure 1 The circuit topology of a power unit in an embodiment of this disclosure is shown. The power unit 100 provided in this embodiment includes a power branch 1 and a clamping branch 2. The power branch 1 and the clamping branch 2 are connected in parallel.

[0057] Power branch 1 includes at least one main switch transistor 10 connected in parallel. The main switch transistor 10 can be a low-voltage power electronic chip with a drain D, a source S, and a gate G. Its drain D can be connected to a high-voltage electrode, and its source S can be connected to a low-voltage electrode.

[0058] Clamping branch 2 includes an auxiliary switching transistor 3 connected in series and a clamping capacitor 20. Exemplarily, multiple clamping capacitors 20 can be connected in parallel. Multiple auxiliary switching transistors 3 can also be provided. The auxiliary switching transistor 3 can be a low-voltage power electronic chip with a drain (D), source (S), and gate (G), such as... Figure 1 As shown, its drain D can be connected to a low-voltage electrode, and its source S can be connected to a high-voltage electrode.

[0059] Combination Figure 2 As shown, Figure 2 The power unit in an embodiment of this disclosure is shown. Figure 3 yes Figure 2 A top view. In some embodiments, the power unit 100 further includes a patterned first metal layer 14. The aforementioned components may be soldered to the first metal layer 14. The first metal layer 14 may include a first pair of terminal patterns 15, a power pattern 16, a low-voltage pattern 17, a high-voltage pattern 18, and a second pair of terminal patterns 19 arranged sequentially along the X-axis. The first pair of terminal patterns 15 may include two separated terminal patterns, and the second pair of terminal patterns 19 may include two separated terminal patterns.

[0060] For example, the components of the power unit 100 can be soldered to a metal-clad substrate structure, such as a copper-clad ceramic plate. Along a direction perpendicular to the XY plane, the metal-clad substrate structure may include a second metal layer 25 stacked sequentially. Figure 11The substrate and the first metal layer 14. In the XY plane, the metal-clad substrate structure can be a single piece or divided into multiple blocks. For example, the substrate can be divided into a first substrate 11, a second substrate 12, and a third substrate 13.

[0061] Figure 4 The first block of the power unit provided in this embodiment is shown. Exemplarily, the power pattern 16, low-voltage pattern 17, and high-voltage pattern 18 are located on the second substrate 12. The second substrate 12 is relatively large and can be a single, solid substrate. The second substrate 12 can be considered as the main substrate. The first pair of terminal patterns 15 can be located on the first substrate 11, and the second pair of terminal patterns 19 can be located on the third substrate 13. By providing the second substrate 12, the structural strength of the power unit 100 can be improved, thus enhancing its reliability. Simultaneously, the division of different patterns, especially the division of the first substrate 11 and the third substrate 13 from the main substrate, can more clearly separate the electric field, ensuring that the power unit has reliable high-density integration characteristics. The first substrate 11 and the third substrate 13 are arranged approximately symmetrically with respect to the second substrate 12.

[0062] Power diagram 16, low-voltage diagram 17, and high-voltage diagram 18 can all be integrated into a single structure. For example... Figure 4 As shown, the power pattern 16 may include a first mounting area 161, a first connection area 162, and a fourth connection area 163 electrically connected as one unit. The first connection area 162 protrudes below the first mounting area 161 along the X-axis. The low-voltage pattern 17 may include a second connection area 171, a fifth connection area 172, and a sixth connection area 173 electrically connected as one unit. The second connection area 171 is located below the first mounting area 161 along the X-axis. The high-voltage pattern 18 may include a second mounting area 181, a third connection area 182, and a seventh connection area 183 electrically connected as one unit. The second mounting area 181 is located on the side of the first connection area 162 opposite to the first mounting area 161 along the X-axis. The third connection area 182 is located on the side of the second connection area 171 opposite to the first mounting area 161 along the X-axis.

[0063] refer to Figure 3 and Figure 4 The first mounting area 161 houses the main switching transistor 10 and is electrically connected to its drain D. The second connection area 171 is electrically connected to the source S of the main switching transistor 10. The second mounting area 181 houses the auxiliary switching transistor 3 and is electrically connected to its drain D. The first connection area 162 is electrically connected to the source of the auxiliary switching transistor 3. The power unit 100 may include a plurality of clamping capacitors 20. The first terminal of the clamping capacitor 20 is electrically connected to ground in the second connection area 171, and the second terminal of the clamping capacitor 20 is electrically connected to ground in the third connection area 182. Exemplarily, the sixth connection area 173 and the seventh connection area 183 are used to mount some clamping capacitors 20.

[0064] In some embodiments, the power unit 100 further includes a main gate signal terminal 4, a main source signal terminal 5, an auxiliary gate signal terminal 6, and an auxiliary source signal terminal 7. The main gate signal terminal 4 is electrically connected to the gate G of the main switch transistor 10, and the main source signal terminal 5 is electrically connected to the source S of the main switch transistor 10; the auxiliary gate signal terminal 6 is electrically connected to the gate G of the auxiliary switch transistor 3, and the auxiliary source signal terminal 7 is electrically connected to the source S of the auxiliary switch transistor 3.

[0065] The power branch 1 and the clamping branch 2 are arranged along the X-axis direction, i.e., the first direction. The main gate signal terminal 4 and the main source signal terminal 5 are located on the side of the power branch 1 away from the clamping branch 2, and the auxiliary gate signal terminal 6 and the auxiliary source signal terminal 7 are located on the side of the clamping branch 2 away from the power branch 1.

[0066] The distribution design of the high electric field region and low electric field region inside the power unit provided in this embodiment ensures the electrical reliability of the power unit.

[0067] refer to Figure 3 The main gate signal terminal 4 and the main source signal terminal 5 are arranged perpendicular to the X-axis direction; the auxiliary gate signal terminal 6 and the auxiliary source signal terminal 7 are arranged perpendicular to the X-axis direction. This layout is compact and facilitates closer electrical connection between the terminals and external circuits, thereby increasing the power density of the power unit 100 circuit structure.

[0068] For example, power branch 1 includes at least two main switching transistors 10 connected in parallel. (e.g.) Figure 3 The diagram shows two main switching transistors 10, arranged perpendicular to the X-axis. The clamping branch 2 includes at least two clamping capacitors 20 connected in parallel, and may also include multiple auxiliary switching transistors 3 connected in parallel. (Example...) Figure 3 The diagram shows an auxiliary switch 3 and two clamping capacitors 20, with the overall arrangement of the clamping capacitors 20 and the auxiliary switch 3 along the Y-axis. The clamping capacitors 20 can have different sizes. The circuit connection design ensures that the low-voltage terminals of the clamping capacitors 20 face the power branch 1, while the high-voltage terminals of the clamping capacitors 20 face away from the power branch 1.

[0069] The main gate signal terminal 4 and the main source signal terminal 5 are both located in the first pair of terminal patterns 15, and can each be located in a separate terminal pattern. The auxiliary gate signal terminal 6 and the auxiliary source signal terminal 7 are electrically connected to ground in the second pair of terminal patterns 19, and can each be located in a separate terminal pattern. The main switch 10 is located in the power pattern 16. The auxiliary switch 3 is located in the high-voltage pattern 18. For example, the auxiliary switch 3 is located on the left side and its drain D is electrically connected to the power pattern 16, while the clamping capacitor 20 is located on the right side. The low-voltage end of the clamping capacitor 20 is electrically connected to the low-voltage pattern 17, and the high-voltage end of the clamping capacitor 20 is electrically connected to the high-voltage pattern 18. In other words, the end of the clamping capacitor 20 electrically connected to ground in the low-voltage pattern 17 can be called the low-voltage end, and the end electrically connected to ground in the high-voltage pattern 18 can be called the high-voltage end. The layout of the auxiliary switch 3, the high-voltage pattern 18, and the clamping capacitor 20 is roughly in the shape of a "U". The pattern of the first metal layer 14 ensures the separation of electric fields in different areas. By arranging the clamping branch 2, the impact of the clamping branch 2 on the normally operating power branch 1 can be reduced, and the electric field distribution of the clamping branch 2 is good.

[0070] For example, the first pair of terminal patterns 15 are electrically connected to the main switch tube 10 via metal wire bonding; the second pair of terminal patterns 19 are electrically connected to the auxiliary switch tube 3 via metal wire bonding.

[0071] The power unit 100 also includes a low-voltage sampling terminal 9 and a high-voltage sampling terminal 8. The low-voltage sampling terminal 9 is electrically connected to ground in the low-voltage pattern 17, and the high-voltage sampling terminal 8 is electrically connected to ground in the high-voltage pattern 18. Based on the positions of the patterns in the first metal layer 14, the low-voltage sampling terminal 9 is closer to the power branch 1 than the high-voltage sampling terminal 8. By configuring the positions of each sampling terminal, interference during sampling can be reduced, and a good sampling effect for the clamping capacitor voltage can be achieved. In the circuit topology, the high-voltage pattern 18 may have a high voltage potential characteristic, and the low-voltage pattern 17 may have a low voltage potential characteristic.

[0072] For example, the first metal layer 14 has a central axis position located between the power branch 1 and the clamping branch 2. This central axis can be the axis of symmetry of the second substrate 12 parallel to the Y-axis direction, i.e., located at the middle position along the X-axis direction. (See reference...) Figure 3 The power pattern 16 includes a fourth connection region 163 located at the central axis position, and the low-voltage pattern 17 includes a fifth connection region 172 located at the central axis position. The fourth connection region 163 and the fifth connection region 172 can be used for electrical connection with external components.

[0073] For example, the first metal layer 14 further includes a main source bar 21, a main gate bar 22, an auxiliary gate bar 23, and an auxiliary source bar 24. The main source bar 21 and the main gate bar 22 are located between the power branch 1 and the first pair of terminal patterns 15. The source S of each main switch 10 can be electrically connected to the main source bar 21 via wire bonding, and the main source signal terminal 5 can be electrically connected to the main source bar 21. The gate G of each main switch 10 can be electrically connected to the main gate bar 22 via wire bonding, and the main gate signal terminal 4 can be electrically connected to the main gate bar 22. Similarly, the gate G of the auxiliary switch 3 can be electrically connected to the auxiliary gate bar 23 via wire bonding, and the auxiliary gate signal terminal 6 can be electrically connected to the auxiliary gate bar 23. The source S of the auxiliary switch 3 can be connected to the auxiliary source bar 24 via wire bonding, and the auxiliary source signal terminal 7 can be electrically connected to the auxiliary source bar 24. The power branch 1 and the clamping branch 2 are easy to expand, and for example, main switch 10 can be added relatively easily.

[0074] For example, the power unit 100 may further include a freewheeling diode (not shown), such as a first freewheeling diode connected in anti-parallel to the main switch 10, or a second freewheeling diode connected in anti-parallel to the auxiliary switch 3. The cathode of the first freewheeling diode may be connected to the drain D of the main switch 10, and the anode of the first freewheeling diode may be connected to the source S of the main switch 10. In other words, the freewheeling diode may be connected in anti-parallel to the power branch 1. The cathode of the second freewheeling diode may be connected to the drain D of the auxiliary switch 3, and the anode of the second freewheeling diode may be connected to the source S of the auxiliary switch 3.

[0075] Figure 5 A power module provided in an embodiment of this disclosure is shown. Figure 6 for Figure 5 A top view. In another aspect, this disclosure provides a power module 200. The power module 200 includes at least two power units 100, which can be those described in the foregoing embodiments. These power units 100 can be arranged sequentially along a Y-axis direction perpendicular to the X-axis direction, and these power units 100 are connected in series.

[0076] Developing a series topology power module suitable for active clamping control strategies is of paramount importance for fully validating active clamping technology in the field of high-voltage, high-power conversion. Developing a series topology power module also facilitates the industrialization of active clamping technology 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 urgent to develop a low-cost high-voltage, high-power module based on a series low-voltage power electronic chip and employing an active clamping control strategy. Therefore, the series topology power module based on a low-voltage electronic chip and employing active clamping voltage equalization control provided in this disclosure has significant application prospects and economic value.

[0077] The power module provided in this disclosure can be connected in series using standardized power units, which greatly simplifies the expansion of the voltage and current levels of the power module and improves the electrical reliability of the power module.

[0078] For example, such as Figure 6 Six power units 100 are shown arranged in a row and connected in series, but other numbers of power units 100 can also be used. This row of power units 100 includes a first power unit 101 at one end, a second power unit 102 at the other end, and at least one third power unit 103 in the middle of the row. The power module 200 includes two electrodes, of which a first electrode 32 is electrically connected to the first power unit 101, and a second electrode 33 is electrically connected to the second power unit 102.

[0079] For example, the power units 100 are arranged along the Y-axis. The arrangement of at least two main gate signal terminals 4 and at least two main source signal terminals 5 is perpendicular to the X-axis, and the arrangement of at least two auxiliary gate signal terminals 6 and at least two auxiliary source signal terminals 7 is perpendicular to the X-axis.

[0080] For example, power branch 1 includes at least two main switching transistors 10 connected in parallel, and the arrangement direction of the at least two main switching transistors 10 is perpendicular to the X-axis direction. Clamping branch 2 may include at least two clamping capacitors 20 connected in parallel, and the arrangement direction of the auxiliary switching transistors 3 and clamping capacitors 20 is perpendicular to the X-axis direction. Power module 200 can greatly simplify the expansion methods of voltage and current levels, facilitating high-density integration of power module 200 with external drive circuits and control circuits. The voltage level can be expanded by increasing the number of power units 100 connected in series inside power module 200, and the current level can be expanded by increasing the number of main switching transistors 10 connected in parallel inside power module 200, while the design of external drive circuits and control circuits does not require cumbersome modifications.

[0081] refer to Figure 3 For example, the first metal layer 14 has a central position located between the power branch 1 and the clamping branch 2. The power pattern 16 includes a fourth connection region 163 located at the central position, and the low-voltage pattern 17 includes a fifth connection region 172 located at the central position. The power module 200 includes at least one series connection structure 34. The series connection structure 34 overlaps two adjacent power units 100, and in two adjacent power units, the fourth connection region 163 of one is electrically connected to the fifth connection region 172 of the other through the series connection structure 34. For example, the fourth connection region 163 of the first power unit 101 is electrically connected to the first electrode 32, and the fifth connection region 172 of the second power unit 102 is electrically connected to the second electrode 33. The power module 200 has a compact structure, and the series connection structures 34 are neatly positioned, which helps to equalize the voltage of each power unit 100.

[0082] Figure 7 The circuit topology of the power module provided in this embodiment is shown. In the power module 200, the number of power units 100 connected in series is N, where N is a positive integer greater than or equal to 2. The withstand voltage of the power module 200 is N times the withstand voltage of the power units 100.

[0083] Figure 8 The layout features of a power module provided in this embodiment are shown. The power module 200 may have a long axis parallel to the Y-axis direction, which may pass through the centroid of the power module 200. A first electrode 32 may serve as a power electrode DC+, and a second electrode 33 may serve as a power electrode DC-. The main power branch of the power module 200 includes power branches 1 of each power unit 100 and a series connection structure 34, the main power branch being generally in a "I" shape and located parallel to one side of the long axis. Clamping branches 2 of each power unit 100 may be located side-by-side on the other side of the long axis, these clamping branches 2 may each be in a "U" shape. Furthermore, high-voltage sampling terminals 8 and low-voltage sampling terminals 9 are located near the long axis and are periodically distributed along the Y-axis direction.

[0084] Figure 9 The metal-clad insulation structure of the power module provided in this embodiment is shown. (Refer to the figure.) Figure 6 Multiple power units 100 may be disposed on one side of the metal-clad insulating structure 30. A base plate 31 is disposed on the other side of the metal-clad insulating structure 30. Notches may be formed at the four corners of the metal-clad insulating structure 30 to expose the base plate 31. The metal-clad insulating structure 30 may include a stacked third metal layer 301, an insulating plate 302, and a fourth metal layer 303. Figure 11 The third metal layer 301 can be divided into multiple parts, each corresponding to a power unit 100. When the power unit 100 includes, for example, three blocks, the third metal layer 301 can include a metal portion corresponding to each block.

[0085] Figure 10 A power module according to an embodiment of this disclosure is shown. The power module 200 also includes a frame 35 and a cover 37. (Reference) Figure 5 The four corners of the frame 35 can be bonded to the base plate 31 through the metal-coated insulation structure 30 or mechanically fixed by other means. The frame 35 surrounds multiple power units 100 and its material can be plastic. The cover 37 is used to cover the multiple power units 100 within the frame 35. The main gate signal terminal 4, main source signal terminal 5, auxiliary gate signal terminal 6, auxiliary source signal terminal 7, low-voltage sampling terminal 9, and high-voltage sampling terminal 8 of each power unit 100 can partially extend out of the cover 37. In addition, the first electrode 32 and the second electrode 33 extend out of the cover 37 and can be fixed to the frame 35 in a matching manner.

[0086] Figure 11 This is a schematic cross-sectional view of a power module provided in this embodiment. The dimensions and shapes of the various parts of this power module 200 are merely exemplary. Figure 11 As shown, the base plate 31 is welded to the metal-clad insulating structure 30 via a second welding layer 311, and a frame 35 is also provided on the base plate 31. Encapsulating material is filled into the frame 35 and cured to form an encapsulation body 36; the cover 37 is not shown in the figure. The metal-clad insulating structure 30 includes a fourth metal layer 303, an insulating plate 302, and a third metal layer 301 stacked sequentially. The fourth metal layer 303 is used for welding to the base plate 31. Multiple power units 100 are arranged side-by-side on the metal-clad insulating structure 30, and these power units 100 are connected in series via at least one series connection structure 34. The insulating plate 302 is used to electrically isolate the power units 100 from the base plate 31, and the dimension of the insulating plate 302 along the Z-axis is greater than or equal to the quotient obtained by dividing the withstand voltage of the power module 200 by the breakdown field strength of the insulating plate 302 material.

[0087] like Figure 11 As shown and referenced Figure 3 , Figure 9 The third metal layer 301 may include different metal portions to correspond to different blocks of the power unit 100. The power unit 100 includes a second metal layer 25, a substrate, and a first metal layer 14 stacked sequentially. The second metal layer 25 is soldered to the metal-clad insulating structure 30 via a first solder layer 26.

[0088] In some embodiments, the metal-clad insulating structure 30 may be an integral structure. For example, Figure 11The diagram shows what may be the main block of the power unit 100. This main block includes a second substrate 12 and metal foils located on both sides of the second substrate 12. The upper metal foil includes patterns not shown, but may include, for example, a high-voltage pattern 18 for soldering to the high-voltage terminals of the auxiliary switching transistor 3, the clamping capacitor 20, and the high-voltage sampling terminal 8, and a power pattern 16 for soldering to the first electrode 32. The lower metal foil may have a rectangular outer contour, which is smaller than the outer contour of the second substrate 12.

[0089] The lower metal foil of the main block is welded to the first metal portion 3011 of the third metal layer 301, and the projection of the first metal portion 3011 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 3011 along the Z-axis is less than the projection of the second substrate 12. This configuration allows the first metal portion 3011 to cover the lower metal foil, ensuring accurate welding of the main block, guaranteeing the electric field distribution within the power module 200, and contributing to improved safety and reliability.

[0090] For example, a small-sized block of the power unit 100 includes a small metal foil, a first substrate 11, and a first pair of terminal patterns 15 stacked sequentially. The small metal foil is soldered to a second metal portion 3012 of the third metal layer 301. The projection of the second metal portion 3012 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 11.

[0091] 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.

[0092] 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, based on an active clamping circuit topology, characterized in that, The power unit includes: Main switching transistor; A patterned first metal layer, the first metal layer comprising: The first installation area is where the main switch transistor is installed and electrically connected to the drain of the main switch transistor; A first connection area protrudes from one side of the first mounting area along a first direction, and the first connection area is electrically connected to the first mounting area. The second connection area is located on one side of the first mounting area along the first direction, and the second connection area is electrically connected to the source of the main switch transistor. The second mounting area is located along the first direction on the side of the first connection area opposite to the first mounting area; and The third connection area is located along the first direction on the side of the second connection area away from the first mounting area, and the third connection area is electrically connected to the second mounting area. An auxiliary switching transistor is mounted in the second mounting area, the drain of the auxiliary switching transistor is electrically connected to the second mounting area, and the source of the auxiliary switching transistor is electrically connected to the first connection area; and A clamping capacitor, wherein the first terminal of the clamping capacitor is electrically connected to ground in the second connection area, and the second terminal of the clamping capacitor is electrically connected to ground in the third connection area; The main switch is used to form a power branch, and the auxiliary switch and the clamping capacitor are used to form a clamping branch; the first metal layer also includes a first pair of terminal patterns and a second pair of terminal patterns; the power unit also includes a main gate signal terminal, a main source signal terminal, an auxiliary gate signal terminal, an auxiliary source signal terminal, a low-voltage sampling terminal and a high-voltage sampling terminal. The main gate signal terminal and the main source signal terminal are located on the side of the power branch away from the clamping branch, and are electrically connected to the first pair of terminals. The main gate signal terminal is electrically connected to the gate of the main switch, and the main source signal terminal is electrically connected to the source of the main switch. The auxiliary gate signal terminal and the auxiliary source signal terminal are located on the side of the clamping branch away from the power branch, and are electrically connected to the ground in the second pair of terminal patterns. The auxiliary gate signal terminal is electrically connected to the gate of the auxiliary switch, and the auxiliary source signal terminal is electrically connected to the source of the auxiliary switch. The low-voltage sampling terminal is electrically connected to ground in the second connection area, and the high-voltage sampling terminal is electrically connected to ground in the third connection area.

2. The power unit according to claim 1, wherein, The arrangement direction of the main gate signal terminal and the main source signal terminal is perpendicular to the first direction, and the arrangement direction of the auxiliary gate signal terminal and the auxiliary source signal terminal is perpendicular to the first direction; The power branch includes at least two main switching transistors connected in parallel, and the arrangement direction of the at least two main switching transistors is perpendicular to the first direction; The clamping branch includes at least two clamping capacitors connected in parallel, and the auxiliary switching transistor and the clamping capacitors are arranged in a direction perpendicular to the first direction.

3. The power unit according to claim 1, wherein, The first metal layer further includes: a main source electrode strip, a main gate electrode strip, an auxiliary source electrode strip, and an auxiliary gate electrode strip; The main source bar and the main gate bar are located on the side of the first mounting area away from the second connection area. The source of the main switch is electrically connected to the main source signal terminal through the main source bar, and the gate of the main switch is electrically connected to the main gate signal terminal through the main gate bar. The auxiliary source electrode strip and the auxiliary gate electrode strip are located on the side of the second mounting area away from the first connection area. The source of the auxiliary switch is electrically connected to the auxiliary source electrode signal terminal through the auxiliary source electrode strip, and the gate of the auxiliary switch is electrically connected to the auxiliary gate electrode signal terminal through the auxiliary gate electrode strip.

4. The power unit according to any one of claims 1 to 3, 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 first mounting area and the first connection area are used to form an integrated power pattern; the second connection area is used to form an integrated low-voltage pattern; and the second mounting area and the third connection area are used to form an integrated high-voltage pattern.

5. The power unit according to claim 4, wherein, The substrate includes a first substrate, a second substrate, and a third substrate arranged sequentially and separated from each other along the first direction; the power pattern, the low-voltage pattern, and the high-voltage pattern are all located on the second substrate.

6. The power unit according to claim 4, wherein, The first metal layer has a central axis position located between the main switch and the auxiliary switch, the power pattern includes a fourth connection area located at the central axis position, and the low voltage pattern includes a fifth connection area located at the central axis position.

7. A power module, characterized in that, include: At least two power units as described in any one of claims 1 to 6 are connected in series, the power units being arranged sequentially along a second direction perpendicular to the first direction.

8. The power module according to claim 7, wherein, It also includes a metal-clad insulating structure and at least two first welding layers, wherein the at least two first welding layers are arranged sequentially along the metal-clad insulating structure, and the metal-clad substrate structure of the power unit is fixed to the metal-clad insulating structure through the corresponding first welding layer.

9. The power module according to claim 8, wherein, The metal-clad insulating structure includes a third metal layer, an insulating plate, and a fourth metal layer stacked sequentially in a direction away from the power unit. The projection of each metal portion of the third metal layer along the stacking direction covers the lower metal foil of the metal-clad substrate structure and is covered by the projection of the substrate of the metal-clad substrate structure.

10. The power module according to claim 8, wherein, The dimension of the insulating plate of the metal-coated 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 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 the at least two first welding layers and is fixedly connected to the base plate through the notches.

12. The power module according to claim 7, 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 switch, the anode of the first freewheeling diode is electrically connected to the source of the main switch, the cathode of the second freewheeling diode is electrically connected to the drain of the auxiliary switch, and the anode of the second freewheeling diode is electrically connected to the source of the auxiliary switch. The withstand voltage of the power module is the product of the withstand voltage of the power unit and the number of power units.

13. The power module according to claim 7, 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 fourth connection region of one is electrically connected to the fifth connection 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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