A power module based on series connection of power electronic chips

Abstract

A power module based on series connection of power electronic chips is disclosed, relating to the field of power electronics technology. The power module consists of multiple power units connected in series. The disclosed power module integrates low-voltage power electronic chips at a high density, improving the voltage and current ratings of the power module. Its advantages include: the proposed high-density series structure design reduces the parasitic inductance of the module's main power circuit; and the proposed power module and its design avoid the high cost and high loss disadvantages associated with using high-voltage power electronic devices to achieve high-voltage, high-current power conversion.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to a power module and its structural design that uses power electronic chips connected in series with active clamping voltage equalization technology. Background Technology

[0002] 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.

[0003] 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.

[0004] 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.

[0005] 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.

[0006] 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 technologies with numerous drawbacks, it is urgent to develop low-cost high-voltage, high-power modules based on series-connected low-voltage power electronic chips and employing active clamping control strategies. Developing series-topology power modules suitable for active clamping control strategies is of paramount importance for fully validating active clamping technologies in the field of high-voltage, high-power conversion. Developing series-topology power modules is also an essential step towards the industrialization of active clamping technologies in high-voltage, high-power conversion. Series-topology power modules based on low-voltage electronic chips and employing active clamping voltage equalization control have enormous application prospects and economic value. Summary of the Invention

[0007] To address one or more of the technical problems of the prior art, this invention proposes a power module based on series connection of power electronic chips and its structural design.

[0008] According to an embodiment of the present invention, a power module based on series connection of power electronic chips is proposed, characterized in that it includes: a base plate; a first solder layer located on the upper surface of the base plate; and a power unit, which includes a first DBC structure, a second DBC structure, a third DBC structure, a second solder layer, a main switching power electronic chip, an auxiliary switching power electronic chip, a clamping capacitor, a main switching gate signal terminal, a main switching source signal terminal, an auxiliary switching gate signal terminal, an auxiliary switching source signal terminal, and a clamping capacitor voltage sampling signal terminal, wherein the first DBC structure, the second DBC structure, or the third DBC structure all include a lower layer. The power unit comprises a copper foil, an intermediate ceramic layer, and an upper copper foil. The lower copper foil is located on the upper surface of the first solder layer, and the second solder layer is located on the upper surface of the upper copper foil. The main power switch chip or the auxiliary power switch chip is located on the upper surface of the second solder layer. The circuit topology of the power unit includes a main power branch and an active clamping branch connected in parallel. The main power branch includes the main power switch chip connected in parallel, while the active clamping branch includes the auxiliary power switch chip and a clamping capacitor connected in series. Power electrodes, including a "DC+" power electrode and a "DC-" power electrode, are located on the upper copper foil. A series connection structure, located on the upper copper foil, is used to realize the series connection of multiple power units arranged in parallel; and multiple power units are arranged in parallel inside the power module, and the multiple power units are connected in series through the series connection structure. The "DC+" power electrode is located on the first DBC structure of the first power unit in parallel, and the "DC-" power electrode is located on the first DBC structure of the last power unit in parallel. The gate signal terminal and source signal terminal of the main switch transistor arranged on the second DBC structure, and the gate signal terminal and source signal terminal of the auxiliary switch transistor arranged on the third DBC structure are all located on a straight line parallel to the center line of the long axis of the power module, and the straight line is located in a long outer side region of the power module.

[0009] According to another embodiment of the present invention, a series topology power module is provided, comprising: a power unit, which includes a first DBC structure, a second DBC structure, a third DBC structure, a second solder layer, a main switching transistor power electronic chip, an auxiliary switching transistor power electronic chip, a clamping capacitor, a main switching transistor gate signal terminal, a main switching transistor source signal terminal, an auxiliary switching transistor gate signal terminal, an auxiliary switching transistor source signal terminal, and a clamping capacitor voltage sampling signal terminal, wherein the first DBC structure, the second DBC structure, or the third DBC structure each includes a lower copper foil, an intermediate ceramic layer, and an upper copper layer. The upper copper foil is located on the surface of the first solder layer, and the lower solder layer is located on the surface of the upper copper foil. The main switching power electronic chip or the auxiliary switching power electronic chip is located on the surface of the second solder layer. The circuit topology of the power unit includes a main branch and an active clamping branch connected in parallel. The main branch includes the main switching power electronic chip connected in parallel, and the active clamping branch includes the auxiliary switching power electronic chip and the clamping capacitor connected in series. The power electrodes include a "DC+" power electrode and a "DC-" power electrode, which are located on the upper copper foil. A series connection structure is located on the upper copper foil to realize the series connection of multiple power units in parallel; and multiple power units are arranged in parallel inside the power module, and the multiple power units in parallel are connected together through the series connection structure. The "DC+" power electrode is located on the first DBC structure of the first power unit in parallel, and the "DC-" power electrode is located on the first DBC structure of the last power unit in parallel. The gate signal terminal and source signal terminal of the main switch transistor arranged on the second DBC structure, and the gate signal terminal and source signal terminal of the auxiliary switch transistor arranged on the third DBC structure are all located on a straight line parallel to the center line of the long axis of the power module, and the straight line is located in a long outer side region of the power module. Preferably, the number of power units connected in series within the power module is N, where N is a natural number greater than or equal to 2. The withstand voltage of the power module is equal to N times the withstand voltage of the power unit. The number of parallel connections of the main switching power electronic chip, the number of parallel connections of the auxiliary switching power electronic chip, and the number of parallel connections of the clamping capacitor in the power unit can all be greater than or equal to 1. The sizes of the clamping capacitors can be different from each other. In the power unit, the main switching power electronic chip or the auxiliary switching power electronic chip can also be connected in anti-parallel to a freewheeling diode chip. The so-called anti-parallel connection means that the cathode of the freewheeling diode chip is connected to the drain of the main switching power electronic chip, and the anode of the freewheeling diode chip is connected to the source of the main switching power electronic chip. Preferably, the second DBC structure in the power unit can be completely identical to the third DBC structure. The second DBC structure can also be integrated with the third DBC structure into a single structure, or the second DBC structure and the third DBC structure can be integrated with the first DBC structure into a single structure. The so-called single structure means that the integrated DBC structure contains only a single whole intermediate ceramic layer. Prior to this, in the power unit, the upper copper foil area of ​​the first DBC structure adjacent to the second DBC structure is the gate and source bar area of ​​the gate-source path of the main switching power electronic chip; the upper copper foil area of ​​the first DBC structure adjacent to the third DBC structure is the gate and source bar area of ​​the gate-source path of the auxiliary switching power electronic chip; the "L"-shaped area for arranging the main switching power electronic chip is adjacent to the area of ​​the gate and source bar of the gate-source path of the main switching power electronic chip; the "L"-shaped area for arranging the auxiliary switching power electronic chip is adjacent to the area of ​​the gate and source bar of the gate-source path of the auxiliary switching power electronic chip; the area for arranging the series connection structure is generally "J"-shaped, and the copper foil area corresponding to the bottom of the "J" shape is nested within the... Between the two "L"-shaped regions; in the first DBC structure, the region in the upper copper foil of the first DBC structure where the series connection structure is arranged, the region where the low-voltage pin of the clamping capacitor is arranged, and the region where the capacitor voltage sampling terminal for sampling the low potential voltage of the clamping capacitor is arranged are a single connected region in the shape of "J". This single connected region is characterized by a low voltage potential in the circuit topology; the region in the upper copper foil of the first DBC structure where the auxiliary switching power electronic chip is arranged, the region where the high-potential voltage pin of the clamping capacitor is arranged, and the region where the capacitor voltage sampling terminal for sampling the high potential voltage of the clamping capacitor is arranged are a single connected region in the shape of "L". This single connected region in the shape of "L" is characterized by a high voltage potential in the circuit topology, and the short side of the "L" is nested inside the single connected region in the shape of "J". Preferably, the starting point and ending point of the power module connected in series with the power unit are the "DC+" power electrode and the "DC-" power electrode, respectively. The main power branch of the power module is formed by connecting the main branches of the power unit in series. The projection of the main power branch of the power module on the horizontal plane of the power module is a "rectangular wave" shape. The projection path of the "rectangular wave" shape is unfolded along the center line of the long axis of the power module. Each "rectangular" path in the "rectangular wave" shape corresponds to a main branch of the power unit. Each power unit has two paths perpendicular to the center line of the long axis of the power module. These two paths are adjacent to each other and located in the left side region of the power unit.

[0010] Compared with existing technical solutions, the beneficial effects of the power module and its structural design based on series connection of power electronic chips disclosed in this invention are as follows: The proposed series connection technology based on power units arranges the main power circuit of the power module into a "rectangular wave" shape. The "rectangular wave" shape corresponding to a single power unit contains two paths that are perpendicular to and adjacent to the center line of the long axis of the power module. Since their current directions are opposite, the parasitic inductance of the main power circuit of the module is greatly reduced. The proposed series connection technology, which arranges the input signal terminals of the main switch and the auxiliary switch on the same long side of the module, also greatly simplifies the expansion of the voltage and current levels of the power module, facilitating the high-density integration of the power module with the drive circuit and the control circuit. The proposed power module avoids the high cost and high loss disadvantages of using high-voltage power electronic devices to achieve high-voltage and high-current power conversion, and extends the low loss and low cost advantages of low-voltage silicon carbide devices to the field of high-voltage and high-power applications, enhancing the applicability of current commercial silicon carbide devices in the field of high-voltage and high-power applications. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the overall architecture design of the power module according to an embodiment of the present invention; Figure 2 This is a schematic cross-sectional view of the power module according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a power unit structure according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the power unit circuit topology according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the circuit topology of the power module according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the design of the first DBC structure according to an embodiment of the present invention; Figure 7 This is a schematic projection of the internal structure of the power module according to an embodiment of the present invention onto the horizontal plane of the module; Figure 8 This is a schematic diagram showing the overall features of the main power branch of the power module as projected onto the horizontal plane of the module according to an embodiment of the present invention. Detailed Implementation

[0012] Specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. In the following description, numerous specific details are set forth to facilitate a thorough understanding of the invention. However, those skilled in the art will understand that these specific details are not essential for carrying out the invention. Furthermore, in some embodiments, well-known circuits, materials, or methods are not specifically described to avoid obscuring the invention.

[0013] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "in an embodiment," "in an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the accompanying drawings provided herein are for illustrative purposes, with the same reference numerals indicating the same elements. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0014] The power electronic chips used in the power module of this invention include, but are not limited to, metal-oxide-semiconductor field-effect transistors (MOSFETs), insulated-gate bipolar transistors (IGBTs), and junction field-effect transistors (JFETs) in terms of chip structure. The materials used in the chips are not limited to silicon (Si), but may 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 the power module of this invention, to clearly illustrate the series and parallel connections of the components in the circuit diagram, the body diode or anti-parallel freewheeling diode in the power electronic chip is omitted.

[0015] Figure 1The diagram below shows the overall architecture design of a power module according to an embodiment of the present invention. The power module includes a base plate 10, a "DC+" power electrode 1, a "DC-" power electrode 2, and multiple parallel power units, forming a series connection structure 70 that connects the power units in series.

[0016] Figure 2 The diagram shows a cross-sectional view of a power module according to an embodiment of the present invention. From bottom to top, the components are: a base plate 10, a first solder layer 11, a power unit DBC structure 30, a second solder layer 12, a main switching transistor power electronic chip 40, an auxiliary switching transistor power electronic chip 50, and a clamping capacitor 60. The power unit DBC structure 30 includes a lower copper foil 31, a middle ceramic layer 32, and an upper copper foil 33.

[0017] Figure 3 The diagram below illustrates the structure of a power unit in a power module according to an embodiment of the present invention. It includes a large DBC structure 34, a small DBC structure 35 for placing the gate signal terminal 4 and source signal terminal 5 of the main switch transistor, a small DBC structure 36 for placing the gate signal terminal 6 and source signal terminal 7 of the auxiliary switch transistor, a main switch transistor power electronic chip 40, an auxiliary switch transistor power electronic chip 50, a clamping capacitor 60, a high-potential voltage sampling terminal 8 for the clamping capacitor, and a low-potential voltage sampling terminal 9 for the clamping capacitor.

[0018] Figure 4 This is a schematic diagram of the circuit topology of the power unit in the power module according to an embodiment of the present invention. The main power branch is the path from the drain (D) to the source (S) of the main switch Q1. The active clamping branch is formed by the auxiliary switch Q2 connected in series with the clamping capacitor C1. The drain (D) of the auxiliary switch Q2 is connected to the high-potential voltage pin of the clamping capacitor C1, the source (S) of the auxiliary switch Q2 is connected to the drain (D) of the main switch Q1, and the low-potential voltage pin of the clamping capacitor C1 is connected to the source (S) of the main switch. Figure 4 As shown, the drain (D) of the main switch Q1 is connected to the source (S) of the auxiliary switch Q2, and the source (S) of the main switch Q1 is connected to the low-potential voltage pin of the clamping capacitor C1. Therefore, the power unit is a parallel connection of the main power branch and the active clamping branch in the circuit topology.

[0019] Figure 5 The diagram below shows the circuit topology of a power module according to an embodiment of the present invention. The circuit topology of the power module is formed by connecting N power units in series. The number of parallel connections of the main switching transistor power electronic chip Q1, the auxiliary switching transistor power electronic chip Q2, or the clamping capacitor C1 of the power units can all be greater than or equal to 1.

[0020] Figure 6 The diagram illustrates the design of the first DBC structure of the power unit according to an embodiment of the present invention. The upper copper foil of the DBC structure of the main power branch includes: a gate strip 110 for arranging the gate-source path of the main power switch chip, a source strip 120 for arranging the gate-source path of the main power switch chip, and a region 130 for arranging the main power switch chip. The upper copper foil of the DBC structure of the auxiliary power branch includes: a gate strip 111 for arranging the gate-source path of the auxiliary power switch chip, a source strip 121 for arranging the gate-source path of the auxiliary power switch chip, a region 131 for arranging the auxiliary power switch chip, and a region 150 for arranging the series structure. All the upper copper foils of the DBC structure are located on the upper surface of the intermediate ceramic layer 32 of the DBC structure.

[0021] Figure 7 This is a schematic projection of the internal structure of the power module according to an embodiment of the present invention onto the horizontal plane of the module. Figure 7 Six power units are connected in series and arranged in parallel along the long axis of the power module. The "DC+" power electrode 1 is arranged on the first power unit, the "DC-" power electrode 2 is arranged on the last power unit, and the series connection structure 70 is arranged on one side of the long axis of the power module. Its projection on the horizontal plane of the module is periodically distributed near the long axis of the module. The signal terminals are arranged on the other side of the long axis of the power module.

[0022] Figure 8 This is a schematic diagram showing the overall characteristics of the main power branch of the power module after being projected onto the horizontal plane of the module according to an embodiment of the present invention. The main power branch points from "DC+" to "DC-". The main power branch is formed by connecting the main branches of the power unit in series and is in the shape of a "rectangular wave". The shape of the "rectangular wave" is distributed parallel to the center line of the long axis of the power module.

[0023] One embodiment of the present invention proposes a power module based on series connection of power electronic chips, such as... Figure 1 , Figure 2 and Figure 3As shown, the feature is that it includes: a base plate 10; a first solder layer 11 located on the upper surface of the base plate 10; and a power unit, which includes a first DBC structure 34, a second DBC structure 35, a third DBC structure 36, a second solder layer 12, a main switching transistor power electronic chip 40, an auxiliary switching transistor power electronic chip 50, a clamping capacitor 60, a main switching transistor gate signal terminal 4, a main switching transistor source signal terminal 5, an auxiliary switching transistor gate signal terminal 6, an auxiliary switching transistor source signal terminal 7, and clamping capacitor voltage sampling signal terminals 8 and 9, wherein the first DBC structure 34, the second DBC structure 35, or the third DBC structure 36 each includes a lower copper foil 31 and an intermediate ceramic layer. The power unit consists of a ceramic layer 32 and an upper copper foil 33. The lower copper foil is located on the upper surface of the first solder layer 11, and the second solder layer 12 is located on the upper surface of the upper copper foil 33. The main switching transistor power electronic chip 40 or the auxiliary switching transistor power electronic chip 50 is located on the upper surface of the second solder layer 12. The circuit topology of the power unit includes a main branch and an active clamping branch connected in parallel. The main branch includes the main switching transistor power electronic chip 40 connected in parallel, while the active clamping branch includes the auxiliary switching transistor power electronic chip 50 and a clamping capacitor 60 connected in series with it. Power electrodes include a "DC+" power electrode 1 and a "DC-" power electrode 2, which are located on the upper copper foil 33. A series connection structure 70, located on the upper copper foil 33, is used to realize the series connection of multiple power units in parallel; and multiple power units are arranged in parallel inside the power module, and the multiple power units in parallel are connected together through the series connection structure 70. The "DC+" power electrode 1 is located on the first DBC structure 34 of the first power unit in parallel, and the "DC-" power electrode 2 is located on the first DBC structure 34 of the last power unit in parallel. The gate signal terminal 4 and source signal terminal 5 of the main switch transistor arranged on the second DBC structure 35, and the gate signal terminal 6 and source signal terminal 7 of the auxiliary switch transistor arranged on the third DBC structure 36 are all located on a straight line parallel to the center line of the long axis of the power module, and the straight line is located in a long outer side region of the power module.

[0024] The power module is characterized in that the number of power units connected in series within it is N, and N is a natural number greater than or equal to 2, such as... Figure 1 As shown, the withstand voltage of the power module is N times the withstand voltage of the power unit.

[0025] The power unit, such as Figure 5As shown, the feature is that the number of parallel connections of the main switching power electronic chip, the number of parallel connections of the auxiliary switching power electronic chip, and the number of parallel connections of the clamping capacitor can all be greater than or equal to 1, wherein the size of the clamping capacitor can be different from each other.

[0026] The power unit is characterized in that the main switching power electronic chip or the auxiliary switching power electronic chip can also be connected in anti-parallel to a freewheeling diode chip. The so-called anti-parallel connection means that the cathode of the freewheeling diode chip is connected to the drain of the switching power electronic chip, and the anode of the freewheeling diode chip is connected to the source of the switching power electronic chip.

[0027] The power unit, such as Figure 3 As shown, the second DBC structure 35 can be completely identical to the third DBC structure 36, or the second DBC structure 35 can be integrated with the third DBC structure 36 into a single structure, or the second DBC structure 35 and the third DBC structure 36 can be integrated with the first DBC structure 34 into a single structure. The so-called single structure means that the integrated DBC structure contains only a single whole intermediate ceramic layer 32.

[0028] The first DBC structure, such as Figure 6 As shown, the feature is that the upper copper foil region of the first DBC structure 34 adjacent to the second DBC structure 35 is the gate strip 110 and source strip 120 region of the gate-source path of the main switching power electronic chip; the upper copper foil region of the first DBC structure adjacent to the third DBC structure is the gate strip 111 and source strip 121 region of the gate-source path of the auxiliary switching power electronic chip; the "L"-shaped region 130 for arranging the main switching power electronic chip is adjacent to the gate strip 110 and source strip 120 region of the gate-source path of the main switching power electronic chip; the "L"-shaped region 131 for arranging the auxiliary switching power electronic chip is adjacent to the gate strip 111 and source strip 121 region of the gate-source path of the auxiliary switching power electronic chip; the region 150 for arranging the series connection structure is generally "J"-shaped, and the copper foil region corresponding to the bottom of the "J" shape is nested between the two "L"-shaped regions.

[0029] The first DBC structure, such as Figure 6 and Figure 4As shown, the first DBC structure is characterized by the following: the region in the upper copper foil where the series connection structure 70 is arranged, the region where the low-voltage pin of the clamping capacitor is arranged, and the region where the capacitor voltage sampling terminal 9 for sampling the low potential voltage of the clamping capacitor is arranged are a single connected region 150 in the shape of "J". This single connected region 150 is characterized by a low voltage potential in the circuit topology; the region in the upper copper foil where the auxiliary switching power electronic chip is arranged, the region where the high-potential voltage pin of the clamping capacitor is arranged, and the region where the capacitor voltage sampling terminal 8 for sampling the high potential voltage of the clamping capacitor is arranged are a single connected region 131 in the shape of "L". This "L"-shaped single connected region 131 is characterized by a high voltage potential in the circuit topology, and the short side of the "L" shape is nested inside the "J"-shaped single connected region.

[0030] The series connection structure, such as Figure 7 As shown, the series connection structure 70 is located on the other side of the power module's long axis centerline relative to the second DBC structure 35 or the third DBC structure 36, and its projection on the module's horizontal plane is periodically distributed on a straight line parallel to the module's long axis centerline.

[0031] The power module, such as Figure 8 As shown, the starting point and ending point of the series power units are respectively "DC+" power electrode 1 and "DC-" power electrode 2. The main power branch of the power module is formed by the series connection of the main branches of the power units. The projection of the main power branch of the power module on the horizontal plane of the power module is a "rectangular wave" shape. The "rectangular wave" projection path is unfolded along the center line of the long axis of the power module. Each "rectangular" path in the "rectangular wave" path corresponds to a main branch of the power unit. Each power unit has two paths perpendicular to the center line of the long axis of the power module. These two paths are adjacent to each other and located in the left side region of the power unit.

[0032] A series topology power module and its structural design include: a power unit comprising a first DBC structure, a second DBC structure, a third DBC structure, a second solder layer, a main switching transistor power electronic chip, an auxiliary switching transistor power electronic chip, a clamping capacitor, a main switching transistor gate signal terminal, a main switching transistor source signal terminal, an auxiliary switching transistor gate signal terminal, an auxiliary switching transistor source signal terminal, and a clamping capacitor voltage sampling signal terminal. The first DBC structure, the second DBC structure, and the third DBC structure each comprise a lower copper foil, a middle ceramic layer, and an upper copper foil. The lower copper foil is located on the upper surface of the first solder layer, and the second solder layer is located on the upper surface of the upper copper foil. The main switching power electronic chip or the auxiliary switching power electronic chip is located on the upper surface of the second solder layer. The circuit topology of the power unit includes a main branch and an active clamping branch connected in parallel with it. The main branch includes the main switching power electronic chip connected in parallel, while the active clamping branch includes the auxiliary switching power electronic chip and the clamping capacitor connected in series with it. The power electrodes include a "DC+" power electrode and a "DC-" power electrode, which are located on the upper copper foil. A series connection structure is located on the upper copper foil to realize the series connection of multiple power units in parallel; and multiple power units are arranged in parallel inside the power module, and the multiple power units in parallel are connected together through the series connection structure. The "DC+" power electrode is located on the first DBC structure of the first power unit in parallel, and the "DC-" power electrode is located on the first DBC structure of the last power unit in parallel. The gate signal terminal and source signal terminal of the main switch transistor arranged on the second DBC structure, and the gate signal terminal and source signal terminal of the auxiliary switch transistor arranged on the third DBC structure are all located on a straight line parallel to the center line of the long axis of the power module, and the straight line is located in a long outer side region of the power module. The number of power units connected in series within the power module is N, where N is a natural number greater than or equal to 2. The withstand voltage of the power module is equal to N times the withstand voltage of each power unit. The number of parallel connections of the main switching power electronic chip, the auxiliary switching power electronic chip, and the clamping capacitor in the power unit can all be greater than or equal to 1, and the sizes of the clamping capacitors can be different. In the power unit, the main switching power electronic chip or the auxiliary switching power electronic chip can also be connected in anti-parallel to a freewheeling diode chip. Anti-parallel connection means that the cathode of the freewheeling diode chip is connected to the drain of the switching power electronic chip, and the anode of the freewheeling diode chip is connected to the source of the switching power electronic chip. The second DBC structure in the power unit can be exactly the same as the third DBC structure. The second DBC structure can also be integrated with the third DBC structure into a single structure, or the second DBC structure and the third DBC structure can be integrated with the first DBC structure into a single structure. The so-called single structure means that the integrated DBC structure contains only a single whole intermediate ceramic layer. In the power unit, the upper copper foil area of ​​the first DBC structure adjacent to the second DBC structure is the gate and source bar area of ​​the gate-source path of the main switching power electronic chip. The upper copper foil area of ​​the first DBC structure adjacent to the third DBC structure is the gate and source bar area of ​​the gate-source path of the auxiliary switching power electronic chip. The "L"-shaped area for arranging the main switching power electronic chip is adjacent to the area of ​​the gate and source bar of the gate-source path of the main switching power electronic chip. The "L"-shaped area for arranging the auxiliary switching power electronic chip is adjacent to the area of ​​the gate and source bar of the gate-source path of the auxiliary switching power electronic chip. The area for arranging the series connection structure is generally "J"-shaped. The copper foil area corresponding to the bottom of the "J" shape is nested within the two... Between the “L”-shaped regions; In the first DBC structure, the region in the upper copper foil of the first DBC structure where the series connection structure is arranged, the region where the low-voltage pin of the clamping capacitor is arranged, and the region where the capacitor voltage sampling terminal for sampling the low potential voltage of the clamping capacitor is arranged are a single connected region in the shape of “J”, which is characterized by a low voltage potential in the circuit topology; The region in the upper copper foil of the first DBC structure where the auxiliary switching power electronic chip is arranged, the region where the high-potential voltage pin of the clamping capacitor is arranged, and the region where the capacitor voltage sampling terminal for sampling the high potential voltage of the clamping capacitor is arranged are a single connected region in the shape of “L”, which is characterized by a high voltage potential in the circuit topology, and the short side of the “L” is nested inside the single connected region in the shape of “J”; The power module is connected in series with the power unit, with the starting point and ending point being the "DC+" power electrode and the "DC-" power electrode, respectively. The main power branch of the power module is formed by connecting the main branches of the power unit in series. The projection of the main power branch of the power module onto the horizontal plane of the power module is a "rectangular wave" shape. The projection path of the "rectangular wave" shape unfolds along the center line of the long axis of the power module. Each "rectangular" path in the "rectangular wave" shape corresponds to a main branch of the power unit. Each power unit contains two paths perpendicular to the center line of the long axis of the power module. These two paths are adjacent to each other and located in the left side region of the power unit.

[0033] Although the invention has been described with reference to several exemplary embodiments, it should be understood that the terminology used is descriptive and exemplary, and not restrictive. Since the invention can be embodied in many forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A power module based on series connection of power electronic chips, characterized in that, include: Base plate; The first solder layer is located on the upper surface of the base plate; A power unit includes a first DBC structure, a second DBC structure, a third DBC structure, a second solder layer, a main switching transistor power electronic chip, an auxiliary switching transistor power electronic chip, a clamping capacitor, a main switching transistor gate signal terminal, a main switching transistor source signal terminal, an auxiliary switching transistor gate signal terminal, an auxiliary switching transistor source signal terminal, and a clamping capacitor voltage sampling signal terminal. The first, second, or third DBC structure each includes a lower copper foil, an intermediate ceramic layer, and an upper copper foil. The lower copper foil is located on the upper surface of the first solder layer, and the second solder layer is located on the upper surface of the upper copper foil. The main switching transistor power electronic chip or the auxiliary switching transistor power electronic chip is located on the upper surface of the second solder layer. The circuit topology of the power unit includes a main branch and an active clamping branch connected in parallel. The main branch includes a main switching transistor power electronic chip connected in parallel, and the active clamping branch includes an auxiliary switching transistor power electronic chip and a clamping capacitor connected in series with it. The power electrodes, including a "DC+" power electrode and a "DC-" power electrode, are located on the upper copper foil; A series connection structure, located on the upper copper foil, is used to realize the series connection of multiple power units arranged in parallel; and The power module contains multiple power units arranged in parallel, which are connected in series via the series connection structure. The "DC+" power electrode is located on the first DBC structure of the first power unit in parallel, and the "DC-" power electrode is located on the first DBC structure of the last power unit in parallel. The gate signal terminal and source signal terminal of the main switch transistor arranged on the second DBC structure, and the gate signal terminal and source signal terminal of the auxiliary switch transistor arranged on the third DBC structure are all located on a straight line parallel to the long axis centerline of the power module, which is located on a long outer side region of the power module.

2. The power module as described in claim 1, characterized in that, The number of power units connected in series inside is N, where N is a natural number greater than or equal to 2, and the withstand voltage of the power module is equal to N times the withstand voltage of the power unit.

3. The power module as described in claim 1, characterized in that, The number of parallel connections of the main switching power electronic chip, the number of parallel connections of the auxiliary switching power electronic chip, and the number of parallel connections of the clamping capacitor can all be greater than or equal to 1, and the size of the clamping capacitor can be different from each other.

4. The power module as described in claim 1 or 3, characterized in that, The main switching power electronic chip or the auxiliary switching power electronic chip can also be connected in anti-parallel to a freewheeling diode chip. The so-called anti-parallel connection means that the cathode of the freewheeling diode chip is connected to the drain of the main switching power electronic chip, and the anode of the freewheeling diode chip is connected to the source of the main switching power electronic chip.

5. The power module as described in claim 1 or 3, characterized in that, The second DBC structure can be exactly the same as the third DBC structure. The second DBC structure can also be integrated with the third DBC structure into a single structure. Alternatively, the second DBC structure and the third DBC structure can be integrated with the first DBC structure into a single structure. The so-called single structure means that the integrated DBC structure contains only a single, whole intermediate ceramic layer.

6. The power module as described in claim 1, characterized in that, The upper copper foil area of ​​the first DBC structure adjacent to the second DBC structure is the gate and source bar area of ​​the gate-source path of the main switching power electronic chip. The upper copper foil area of ​​the first DBC structure adjacent to the third DBC structure is the gate and source bar area of ​​the gate-source path of the auxiliary switching power electronic chip. The "L"-shaped area for arranging the main switching power electronic chip is adjacent to the area of ​​the gate and source bar of the gate-source path of the main switching power electronic chip. The "L"-shaped area for arranging the auxiliary switching power electronic chip is adjacent to the area of ​​the gate and source bar of the gate-source path of the auxiliary switching power electronic chip. The area for arranging the series connection structure is generally "J"-shaped, and the copper foil area corresponding to the bottom of the "J" shape is nested between the two "L"-shaped areas.

7. The power module as described in claim 1, characterized in that, The region in the upper copper foil of the first DBC structure where the series connection structure is laid out, the region where the low-voltage pin of the clamping capacitor is laid out, and the region where the capacitor voltage sampling terminal for sampling the low potential voltage of the clamping capacitor is laid out are a single connected region in the shape of "J". This single connected region is characterized by a low voltage potential in the circuit topology. The region in the upper copper foil of the first DBC structure where the auxiliary switching power electronic chip is laid out, the region where the high-potential voltage pin of the clamping capacitor is laid out, and the region where the capacitor voltage sampling terminal for sampling the high potential voltage of the clamping capacitor is laid out are a single connected region in the shape of "L". This "L" shaped single connected region is characterized by a high voltage potential in the circuit topology, and the short side of the "L" shape is nested inside the "J" shaped single connected region.

8. The power module as described in claim 1 or 2, characterized in that, The series connection structure is located on the other side of the power module's long axis centerline relative to the second or third DBC structure, and its projection onto the module's horizontal plane is periodically distributed on a straight line parallel to the module's long axis centerline.

9. The power module as described in claim 1 or 2, characterized in that, The power module is connected in series with the power unit, with the starting point and ending point being the "DC+" power electrode and the "DC-" power electrode, respectively. The main power branch of the power module is formed by connecting the main branches of the power unit in series. The projection of the main power branch of the power module onto the horizontal plane of the power module is a "rectangular wave" shape. The "rectangular wave" projection path unfolds along the center line of the long axis of the power module. Each "rectangular" path in the "rectangular wave" path corresponds to a main branch of the power unit. Each power unit contains two paths perpendicular to the center line of the long axis of the power module. The two paths are adjacent to each other and located in the left side region of the power unit.

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