Low inductance power module dual layer substrate terminal structure

Abstract

This invention discloses a low-inductance power module substrate terminal structure. The structure includes a first connection terminal, a second connection terminal, and at least one double-layer power module substrate. Partial areas of the first and second connection terminals are arranged with vertical overlap and form a wiring end at their front ends. The first and second connection terminals each have an extension and a connection portion at their rear ends. The double-layer power module substrate includes a first substrate connection area and a second substrate connection area. The connection portion of the first connection terminal is integrally connected to the first substrate connection area, and the connection portion of the second connection terminal is integrally connected to the second substrate connection area. This structure reduces system loop inductance, effectively reduces voltage spikes during IGBT module turn-off, reduces switching losses, avoids electromagnetic interference, and ensures the performance of the three-phase inverter drive system.

Description

Technical Field

[0001] This invention relates to the field of three-phase inverter drive technology, and in particular to a double-layer substrate terminal structure for a low-inductance power module. Background Technology

[0002] In three-phase inverter drive systems, stray inductance in components and the DC bus causes significant voltage and current spikes during IGBT module turn-on and turn-off. The voltage spike at the moment of IGBT turn-off is particularly large, increasing switching losses, generating strong electromagnetic interference, and even damaging the IGBT module. Traditional solutions to eliminate voltage overshoot caused by stray parameters include designing buffer circuits and using soft-switching technology. Buffer circuits reduce surge voltage by absorbing the energy released instantaneously by stray inductance, while soft-switching technology primarily reduces di / dt, thus decreasing voltage overshoot. However, both methods require additional circuit design and drive, increasing both design complexity and product cost. Therefore, in practical applications, overshoot voltage is often controlled by directly reducing the inductance.

[0003] like Figure 1 As shown, the stray inductance in the three-phase inverter drive system includes the parasitic inductance L1 of the supporting capacitor 41, the stray inductance of the busbar 42, the connection inductance L2 between the IGBT module terminal 43 and the bolt 44, and the stray inductance L3 of the IGBT module 45, etc.; the overshoot voltage is calculated as shown in equation (1):

[0004]

[0005] It is evident that the overshoot voltage in a three-phase inverter drive system increases with the increase of the total inductance mentioned above. The main factors affecting the switching characteristics of the IGBT module are the stray inductance of the busbar and the inductance of the IGBT module and capacitor connection terminals. In particular, the inductance of the connection between the terminals and the module substrate accounts for a large proportion. Therefore, designing a low-inductance structure for the terminals is the best way to reduce the stray inductance of the line. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a low-inductance power module double-layer substrate terminal structure. This structure reduces the system loop inductance while meeting the IGBT module turn-on and turn-off performance requirements, effectively reduces the voltage spike at the moment of IGBT module turn-off, reduces switching losses, avoids electromagnetic interference, and ensures the performance of the three-phase inverter drive system.

[0007] To solve the above-mentioned technical problems, the low-inductance power module dual-layer substrate terminal structure of the present invention includes a first connection terminal, a second connection terminal and at least one dual-layer power module substrate. Partial areas of the first connection terminal and the second connection terminal are arranged overlapping vertically and form a wiring end at the front end. The first connection terminal and the second connection terminal are provided with an extension and a connection portion at their respective rear ends. The dual-layer power module substrate includes a first substrate connection area and a second substrate connection area. The connection portion of the first connection terminal is connected to the first substrate connection area as a whole, and the connection portion of the second connection terminal is connected to the second substrate connection area as a whole.

[0008] Furthermore, the extensions of the first connecting terminal and the second connecting terminal overlap at least partially at a distance.

[0009] Furthermore, the connection portion of the first connection terminal extends to the at least one double-layer power module substrate and is integrally connected with the connection area of ​​the first substrate, and the connection portion of the first connection terminal is arranged laterally along the at least one double-layer power module substrate.

[0010] Furthermore, the connection portion of the second connection terminal extends to the at least one double-layer power module substrate and is integrally connected with the connection area of ​​the second substrate, and the connection portion of the second connection terminal is arranged along the transverse or longitudinal direction of the at least one double-layer power module substrate.

[0011] Furthermore, the actual current paths of the overlapping areas of the first and second connection terminals are parallel and opposite in direction.

[0012] Furthermore, the actual current path of the connection portion of the first connection terminal and the connection area of ​​the first substrate are parallel to and opposite to the actual current path of the connection portion of the second connection terminal and the connection area of ​​the second substrate.

[0013] Furthermore, the at least one dual-layer power module substrate is a dual-layer substrate arranged in parallel at intervals, with the first substrate connection region and the second substrate connection region respectively located on the upper substrate and the lower substrate.

[0014] Because the low-inductance power module dual-layer substrate terminal structure of the present invention adopts the above-mentioned technical solution, namely, the structure includes a first connection terminal, a second connection terminal, and at least one dual-layer power module substrate, the first connection terminal and the second connection terminal are arranged with overlapping portions at intervals and forming a wiring end at the front end, the first connection terminal and the second connection terminal are respectively provided with an extension portion and a connection portion at the rear end, the dual-layer power module substrate includes a first substrate connection area and a second substrate connection area, the connection portion of the first connection terminal is connected to the first substrate connection area as a whole, and the connection portion of the second connection terminal is connected to the second substrate connection area as a whole. This structure reduces the system loop inductance while meeting the IGBT module turn-on and turn-off performance requirements, effectively reduces the voltage spike at the moment of IGBT module turn-off, reduces switching losses, avoids electromagnetic interference, and ensures the performance of the three-phase inverter drive system. Attached Figure Description

[0015] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments:

[0016] Figure 1 This is a schematic diagram of stray inductance in a three-phase inverter drive system.

[0017] Figure 2 This is a schematic diagram of the double-layer substrate wiring terminal structure of the low-inductance power module of the present invention;

[0018] Figure 3 for Figure 2 A plan view;

[0019] Figure 4 This is a schematic diagram of the first connection terminal in this structure;

[0020] Figure 5 This is a schematic diagram of the second connection terminal in this structure;

[0021] Figure 6 This is a schematic diagram showing the lateral arrangement of the connecting portion of the second connecting terminal in this structure;

[0022] Figure 7 This is a schematic diagram of the current flow direction in this structure;

[0023] Figure 8 , Figure 9 and Figure 10 This is a schematic diagram of another embodiment of this structure;

[0024] Figure 11 and Figure 12 This is a schematic diagram of yet another embodiment of this structure;

[0025] Figure 13 This is a schematic diagram of the current flow direction of the first and second connecting terminals and the bent portion in another embodiment of this structure;

[0026] Figure 14 This is a schematic diagram for calculating the inductance of a multilayer busbar. Detailed Implementation

[0027] Implementation, for example Figures 2 to 5 As shown, the low-inductance power module dual-layer substrate terminal structure of the present invention includes a first connection terminal 1, a second connection terminal 2, and at least one dual-layer power module substrate 3. Partial areas of the first connection terminal 1 and the second connection terminal 2 are arranged overlapping vertically and form wiring ends 11 and 21 at the front end. The first connection terminal 1 and the second connection terminal 2 are provided with an extension portion 12 and 22 and a connection portion 13 and 23 at the rear end, respectively. The dual-layer power module substrate 3 includes a first substrate connection area 31 and a second substrate connection area 32. The connection portion 13 of the first connection terminal 1 is connected to the first substrate connection area 31 as a whole, and the connection portion 23 of the second connection terminal 2 is connected to the second substrate connection area 32 as a whole.

[0028] Preferably, the extension 12 of the first connecting terminal 1 and the extension 22 of the second connecting terminal 2 are at least partially spaced and overlap.

[0029] like Figure 2 and Figure 6 As shown, preferably, the connecting portion 13 of the first connecting terminal 1 extends to the at least one double-layer power module substrate 3 and is integrally connected with the first substrate connecting area 31, and the connecting portion 13 of the first connecting terminal 1 is arranged laterally along the at least one double-layer power module substrate 3.

[0030] Preferably, the connecting portion 23 of the second connecting terminal 2 extends to the at least one double-layer power module substrate 3 and is integrally connected with the connecting area 32 of the second substrate, and the connecting portion 23 of the second connecting terminal 2 is arranged along the transverse or longitudinal direction of the at least one double-layer power module substrate 3.

[0031] Figure 2 A schematic diagram of the structure is shown, in which the connection portion 13 of the first connection terminal 1 is arranged laterally along the double-layer power module substrate 3 and the connection portion 23 of the second connection terminal 2 is arranged longitudinally along the double-layer power module substrate 3. Figure 6 A schematic diagram is shown showing that the connection portion 13 of the first connection terminal 1 and the connection portion 23 of the second connection terminal 2 are both arranged laterally along the double-layer power module substrate 3.

[0032] like Figure 7 As shown, preferably, the actual current paths of the overlapping areas of the first connecting terminal 1 and the second connecting terminal 2 are parallel and oppositely distributed.

[0033] Preferably, the actual current path of the connection portion 13 of the first connection terminal 1 and the connection area 31 of the first substrate is parallel to and opposite to the actual current path of the connection portion 23 of the second connection terminal 2 and the connection area 32 of the second substrate.

[0034] Preferably, the at least one double-layer power module substrate 3 is a double-layer substrate arranged in parallel at intervals, and the first substrate connection region 31 and the second substrate connection region 32 are respectively disposed on the upper substrate and the lower substrate.

[0035] Another implementation of this structure is, for example Figure 8 , Figure 9 and Figure 10 As shown, another embodiment with a modified terminal structure is illustrated. The second connection terminal 2 is also arranged vertically below the first connection terminal 1 on the dual-layer power module substrate 3. The first connection terminal 1 includes two extension portions 12 and at least two connection portions 13, and is integrally connected to the first substrate connection area 31 of the dual-layer power module substrate 3. The second connection terminal 2 includes two extension portions 22 and at least two connection portions 23, and is integrally connected to the second substrate connection area 32 of the dual-layer power module substrate 3. The connection portions 13 of the first connection terminal 1 extend along the transverse direction of the dual-layer power module substrate 3, and the connection portions 23 of the second connection terminal 2 extend along the longitudinal direction of the dual-layer power module substrate 3.

[0036] Figure 11 and Figure 12 Another embodiment of this structure is shown, which has the same design as another embodiment of this structure, except that the dual-layer power module substrate 3 is a single-layer substrate. The single-layer substrate has a first metal layer 33 and a second metal layer 34 that have the same function as the first substrate connection area 31 and the second substrate connection area 32. The first metal layer 33 and the second metal layer 34 extend along the plane of the single-layer substrate and are spaced apart by a certain distance. The first metal layer 33 and the second metal layer 34 have the same thickness. The second connection terminal 2 is connected to the second metal layer 34 as a whole, and the first connection terminal 1 is connected to the first metal layer 33 as a whole. The first connection terminal 1 can be connected to the first metal layer 33 by a bending portion 14.

[0037] This type of terminal structure can still achieve the effect of inductance cancellation, such as Figure 12 As shown, the actual current paths between the connection terminals and the monolayer substrate are symmetrically distributed in the horizontal and vertical directions of the monolayer substrate, which cancels out inductance and reduces the connection inductance of the power module; as Figure 13 As shown, the current paths of the bends connecting the first connection terminal 1 and the second connection terminal 2 to the first metal layer 33 and the second metal layer 34 of the monolayer substrate are still parallel, which can further cancel the inductance and reduce the inductance of the connection terminals.

[0038] This structure reduces the stray inductance of the drive main circuit in a three-phase inverter drive system due to the stacked effect of the extended connection terminal area and the double-layer substrate structure. The actual current path is parallel, and the connection terminals and double-layer substrate structure reduce the inductance. Figure 14 Perform inductance calculations. In the diagram, two busbars 51 and 52 are stacked at intervals and connected by conductor 53. Current I flows from the upper busbar 51 through conductor 53 to the lower busbar 52. Then:

[0039]

[0040] φ=S×B=a×h×B=a×h×μ0×I / w (3)

[0041]

[0042] In the formula, L is the inductance, φ is the magnetic flux, I is the current, B is the magnetic induction intensity, a is the busbar length, w is the busbar width, h is the spacing of the stacked busbars, and μ0 is the free permeability.

[0043] The actual current flows through a connection terminal and is connected to a substrate through the connection part. The current then flows from the substrate to another substrate, and the other substrate finally returns to another connection terminal. The substrates are connected by a connecting line. In this process, the current is in a parallel cancellation state under the connection terminal and the double-layer substrate. Therefore, the stacked terminal and double-layer substrate structure can effectively reduce the connection inductance L2 and the stray inductance L3 of the IGBT module.

[0044] The structure was verified by simulating and solving the inductance values ​​of the model using the finite element software ANSYS Q3D. The simulation data showed that the inductance of the stacked design of this structure was reduced by 40% compared with the original non-stacked design, and the inductance of the double-layer power module substrate was reduced by 60% compared with the single-layer substrate. Therefore, this structure effectively reduces the stray inductance of the drive main circuit.

[0045] This structure addresses the impact of stray inductance in the main circuit of a three-phase inverter system on the switching process of the power module. It reduces stray inductance, minimizes the use of stray inductance absorption circuits in the actual design and development of power modules, and reduces design costs while ensuring reliable operation of the power module. It also reduces the overall size and weight of the structure, making the system design more optimized, saving space, and facilitating installation and maintenance. This structure systematically and holistically reduces stray inductance in the main circuit, ensuring reliable operation of the power module.

Claims

1. A low-inductance power module dual-layer substrate terminal structure, comprising a first connection terminal, a second connection terminal, and at least one dual-layer power module substrate, characterized in that: The second connection terminal is arranged vertically below the first connection terminal on the dual-layer power module substrate. The first and second connecting terminals form wiring terminals at their front ends. At their rear ends, the first and second connecting terminals are sequentially provided with two extension portions and at least two connecting portions. The connecting portions of the first connecting terminal extend laterally along the transverse direction of the dual-layer power module substrate; the connecting portions of the second connecting terminal extend longitudinally along the longitudinal direction of the dual-layer power module substrate. The extensions of the first and second connecting terminals overlap at least partially, and the actual current paths in the overlapping areas are parallel and opposite in direction. The dual-layer power module substrate includes a first substrate connection region and a second substrate connection region. The dual-layer power module substrate is a single-layer substrate. The single-layer substrate has a first metal layer and a second metal layer that function identically to the first and second substrate connection regions. The first and second metal layers extend along the plane of the single-layer substrate and are spaced a certain distance apart, and have the same thickness. The connecting portion of the second connecting terminal extends to the monolayer substrate and is integrally connected to the second metal layer. The connecting portion of the first connecting terminal extends to the monolayer substrate and is integrally connected to the first metal layer. The first connecting terminal is connected to the first metal layer by a bent portion. The substrates are connected by a connecting line. The first and second connection terminals are parallel and symmetrically opposite to the actual current paths of the monolayer substrate in the transverse and longitudinal directions of the monolayer substrate, and the current paths of the first and second connection terminals at the bends connecting the first and second metal layers of the monolayer substrate are parallel and opposite to each other.

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