An igbt device directly parallel anpc power module
By using IGBT modules with symmetrical layout and overlapping loop design in parallel, the problem of low current sharing coefficient when IGBT devices are connected in parallel is solved, and uniform current distribution and consistent junction temperature are achieved, thereby improving the reliability of the equipment.
Patent Information
- Application Number
- CN202511516608.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-23
- Publication Date
- 2026-03-03
- Estimated Expiration
- 2045-10-23
AI Technical Summary
When existing IGBT devices are connected in parallel, the current sharing coefficient is low, which leads to uneven current in each branch, inconsistent device losses and junction temperatures, and reduces the reliability of the equipment.
The design employs discrete IGBT modules connected in parallel, combined with symmetrically arranged first and second stacked busbars, AC side busbars, and uniform heat sinks to ensure consistent parameters across all branches. Furthermore, the design utilizes overlapping loops to reduce commutation inductance.
The parallel connection of IGBTs with high current sharing coefficients was achieved, which ensured the uniform distribution of current in each branch, reduced device losses and junction temperature differences, and improved the reliability of the equipment.
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Figure CN121001327B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of circuit technology, and in particular to an ANPC power module with IGBT devices directly connected in parallel. Background Technology
[0002] High-power power electronic devices often require the provision of large currents and voltages to meet the demands of high-power or high-capacity loads. Existing IGBT devices are difficult to provide sufficient current on their own, so multiple IGBT devices are often connected in parallel in the circuit to increase the current-carrying capacity of the device.
[0003] The most important electrical parameter in high-power IGBT parallel connection technology is the current sharing coefficient. The current sharing coefficient refers to the ratio of the average current of each branch in a parallel power circuit to the maximum current of the branch. It measures the uniformity of current distribution, and its ideal value is 1. To achieve a high current sharing coefficient, currently common and agreed-upon technical solutions need to consider the following points:
[0004] (1) Use the same type of IGBT device in the parallel circuit, or ensure that the internal impedance parameters of the device are as consistent as possible;
[0005] (2) Use uniform and symmetrical cooling equipment to ensure that the junction temperature of each IGBT device is similar;
[0006] (3) Symmetrical design of electrical circuits. Symmetrical layout can greatly improve the parameter consistency of each branch, ensure consistent line path length, and guarantee the same impedance parameters.
[0007] (4) The same driving unit is used and the gate driving circuit is symmetrically designed.
[0008] The biggest differences among the various technical solutions are in the implementation of points (3) and (4) above. These two points need to be achieved through structural design and are also the two most difficult points. The electrical circuit layout in the existing technical solutions is difficult to provide a sufficiently small and uniform circuit impedance, resulting in a low current sharing coefficient in each branch of the parallel circuit. Although the total current at the parallel end can meet the load requirements, the uneven current in each branch causes inconsistent losses and junction temperatures of each power device, and even large differences. Devices that carry large currents bear high losses and switching overvoltages, thus these devices bear a high risk of damage and reduced reliability. Summary of the Invention
[0009] To address the problems existing in the prior art, this application provides an ANPC power module with IGBT devices directly connected in parallel.
[0010] An ANPC power module with IGBT devices directly connected in parallel includes: a heat sink, IGBT modules, a first support frame, a fan, a first stacked busbar, a second support frame, an absorption capacitor, a support capacitor, a second stacked busbar, and an AC output side copper busbar. The first support frame is installed within the second support frame, and the heat sink is installed within a cavity in the first support frame. Twelve IGBT modules are arranged evenly in four columns and three rows on the heat sink. A fan is installed on each column of IGBT modules, and the fan is mounted on the side of the IGBT modules. The first stacked busbar is fixedly connected to the top of the first support frame. An absorption capacitor is installed on the top of the first stacked busbar corresponding to each column of IGBT modules. Two identical support capacitors are installed at the bottom of the first support frame. The second stacked busbar is installed on the side of the first support frame away from the fan and connects the fan, the first stacked busbar, and the support capacitors. The end of the first stacked busbar closest to the fan is also connected to the AC output side copper busbar.
[0011] Furthermore, the twelve IGBT modules are sequentially divided into six groups connected in parallel, and connected by the first stacked busbar 5 to form a bridge arm.
[0012] Furthermore, the first stacked busbar includes contact O, contact P, contact N, contact L1, contact L2, and contact L.
[0013] Furthermore, the second stacked busbar includes contact O, contact P, and contact N.
[0014] Furthermore, the power module circuit includes an IGBT module, an absorption capacitor, and a support capacitor. The IGBT module includes switching transistors S11, S12, S21, S22, S31, S32, S41, S42, S51, S52, S61, and S62. Switches S11 and S12 are connected in parallel, S21 and S22 are connected in parallel, S31 and S32 are connected in parallel, S41 and S42 are connected in parallel, S51 and S52 are connected in parallel, and S61 and S62 are connected in parallel.
[0015] Furthermore, the collectors of switching transistors S11 and S12 are connected to contact P, and the emitters of switching transistors S11 and S12 are connected to contact L1.
[0016] The emitters of switching transistors S21 and S22 are connected to the copper busbar 10 on the AC output side, and the collectors of switching transistors S21 and S22 are connected to the contact L1.
[0017] The collectors of switching transistors S31 and S32 are connected to the copper busbar 10 on the AC output side, and the emitters of switching transistors S31 and S32 are connected to the contact L2.
[0018] The emitters of switching transistors S41 and S42 are connected to contact N, and the collectors of switching transistors S41 and S42 are connected to contact L2.
[0019] The emitters of switching transistors S51 and S52 are connected to contact O, and the collectors of switching transistors S51 and S52 are connected to contact L1.
[0020] The emitters of switching transistors S61 and S62 are connected to contact L2, and the collectors of switching transistors S61 and S62 are connected to contact O.
[0021] Furthermore, the absorption capacitor includes CS1, CS2, CS3, and CS4. One end of CS1 is connected to one end of CS2, and the other end of CS1 is connected to contact point P. The other end of CS2 is connected to contact point O. One end of CS3 is connected to one end of CS4, and the other end of CS4 is connected to contact point N. The other end of CS3 is connected to contact point O.
[0022] Furthermore, the supporting capacitor includes C1 and C2, with the two ends of C1 connected to contact point P and contact point O respectively, and the two ends of C2 connected to contact point O and contact point N respectively.
[0023] Furthermore, the equivalent RL parameter from the lower end of switch S21 to contact L is the same as the equivalent RL parameter from the upper end of switch S31 to contact L.
[0024] The equivalent RL parameter from the lower end of switch S22 to contact L is the same as the equivalent RL parameter from the upper end of switch S32 to contact L.
[0025] The equivalent RL parameter from the lower end of switch S51 to contact O is the same as the equivalent RL parameter from the upper end of switch S61 to contact O.
[0026] The equivalent RL parameter from the lower end of switch S52 to contact O is the same as the equivalent RL parameter from the upper end of switch S62 to contact O.
[0027] The equivalent RL parameters of the circuit from the lower end of switch S11 to contact L1, the equivalent RL parameters of the circuit from the upper end of switch S51 to contact L1, and the equivalent RL parameters of the circuit from the upper end of switch S21 to contact L1 are the same.
[0028] The equivalent RL parameters of the circuit from the lower end of switch S12 to contact L1, the equivalent RL parameters of the circuit from the upper end of switch S52 to contact L1, and the equivalent RL parameters of the circuit from the upper end of switch S22 to contact L1 are the same.
[0029] The equivalent RL parameters of the circuit from the lower end of switch S61 to contact L2, the equivalent RL parameters of the circuit from the upper end of switch S41 to contact L2, and the equivalent RL parameters of the circuit from the lower end of switch S31 to contact L2 are the same.
[0030] The equivalent RL parameters of the circuit from the lower end of switch S62 to contact L2, the equivalent RL parameters of the circuit from the upper end of switch S42 to contact L2, and the equivalent RL parameters of the circuit from the lower end of switch S32 to contact L2 are the same.
[0031] The technical effects and advantages of this application are as follows:
[0032] The circuit layout of the power module using discrete IGBT modules, with two IGBT modules directly connected in parallel, ensures that the power module can output a larger current. The symmetrical layout of the first stacked busbar, the second stacked busbar, and the AC side busbar greatly improves the parameter consistency of each branch, achieving a very high current sharing coefficient for the parallel circuit of this module.
[0033] The twelve IGBT modules are evenly and symmetrically arranged in the bottom air-cooled heat sink, with the same heat transfer coefficient, thus ensuring the dynamic and static current equalization performance of the parallel IGBT modules in terms of heat dissipation.
[0034] The twelve IGBT modules are divided into three complementary IGBT switches. Their BUSBAR structure adopts an overlapping loop design, and the forward current path and the freewheeling current path are basically overlapping in the same plane. Because the current directions are opposite, the coupling method cancels out and reduces the commutation loop inductance, resulting in a small commutation inductance.
[0035] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures pointed out in the description and the accompanying drawings. Attached Figure Description
[0036] Figure 1 The diagram shows the IGBT module layout structure in this application;
[0037] Figure 2 This shows a schematic diagram of the structure of the first stacked busbar in this application;
[0038] Figure 3 A schematic diagram of the overall structure of this application is shown;
[0039] Figure 4 This paper shows a schematic diagram of the connection structure between the second support frame and the second stacked busbar in this application;
[0040] Figure 5 This shows a schematic diagram of the structure of the first stacked busbar in this application;
[0041] Figure 6 A schematic diagram of the structure of the second stacked busbar in this application is shown;
[0042] Figure 7 This diagram illustrates the overall structure of this application from another perspective;
[0043] Figure 8 The circuit diagram of the power module in this application is shown;
[0044] In the diagram: 1-Heat sink, 2-IGBT module, 3-First support frame, 4-Fan, 5-First stacked busbar, 6-Second support frame, 7-Absorption capacitor, 8-Support capacitor, 9-Second stacked busbar, 10-AC output side copper busbar Detailed Implementation
[0045] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0046] Furthermore, in the application, the terms "first," "second," and other similar words are not intended to imply any order, quantity, or importance, but are merely used to distinguish different elements, and the terms "upper," "lower," "left," "right," and other similar words are merely positional relationships in the accompanying drawings.
[0047] like Figures 1-7As shown, one embodiment of this application provides an ANPC power module with IGBT devices directly connected in parallel, including: a heat sink 1, IGBT modules 2, a first support frame 3, a fan 4, a first stacked busbar 5, a second support frame 6, an absorption capacitor 7, a support capacitor 8, a second stacked busbar 9, and an AC output side copper busbar 10. The first support frame 3 is installed inside the second support frame 6, and the heat sink 1 is installed in a cavity within the first support frame 3. Twelve IGBT modules 2 are arranged evenly in four columns and three rows on the heat sink 1. Each column of the IGBT module 2 corresponds to a specific IGBT module. Each IGBT module 2 is equipped with a fan 4, which is installed on the side of the IGBT module 2. The first stacked busbar 5 is fixedly connected to the top of the first support frame 3. The top of the first stacked busbar 5 is equipped with an absorption capacitor 7 corresponding to each column of IGBT module 2. The bottom of the first support frame 3 is equipped with two support capacitors 8 of the same type. The second stacked busbar 9 is installed on the side of the first support frame 3 away from the fan 4. The second stacked busbar 9 is used to connect the fan 4, the first stacked busbar 5 and the support capacitors 8. The end of the first stacked busbar 5 near the fan 4 is also connected to an AC output side copper busbar 10.
[0048] like Figure 1 As shown, the twelve IGBT modules 2 are divided into six groups connected in parallel, and are labeled as S11, S12, S21, S22, S31, S32, S41, S42, S51, S52, S61 and S62 respectively. The twelve IGBT modules 2 are connected into a bridge arm by the first stacked busbar 5.
[0049] like Figure 8 As shown, the four absorption capacitors 7 are CS1, CS2, CS3, and CS4, respectively. Figure 5 As shown, the first stacked busbar 5 includes contact O, contact P, contact N, contact L1, contact L2 and contact L, CS1 and CS2 are installed between contact P and contact O, and CS3 and CS4 are installed between contact O and contact N.
[0050] The second stacked busbar 9 includes contact O, contact P, and contact N.
[0051] Circuits using discrete IGBT components to construct power modules, such as... Figure 8As shown, IGBT module 2 consists of a switching transistor and a diode connected in reverse parallel with the switching transistor. The power module circuit includes IGBT module 2, absorption capacitor 7, and support capacitor 8. IGBT module 2 includes switching transistors S11, S12, S21, S22, S31, S32, S41, S42, S51, S52, S61, and S62. Absorption capacitor 7 includes capacitors CS1, CS2, CS3, and CS4. Support capacitor 8 includes capacitors C1 and C2. Switches S11 and S12 are connected in parallel, S21 and S22 are connected in parallel, S31 and S32 are connected in parallel, S41 and S42 are connected in parallel, S51 and S52 are connected in parallel, and S61 and S62 are connected in parallel.
[0052] The two ends of capacitor C1 are connected to contact point P and contact point O respectively, and the two ends of capacitor C2 are connected to contact point O and contact point N respectively.
[0053] One end of capacitor CS1 is connected to one end of capacitor CS2, the other end of capacitor CS1 is connected to contact point P, and the other end of capacitor CS2 is connected to contact point O.
[0054] One end of capacitor CS3 is connected to one end of capacitor CS4, the other end of capacitor CS4 is connected to contact point N, and the other end of capacitor CS3 is connected to contact point O.
[0055] The collectors of switching transistors S11 and S12 are connected to contact P, and the emitters of switching transistors S11 and S12 are connected to contact L1.
[0056] The emitters of switching transistors S21 and S22 are connected to the copper busbar 10 on the AC output side, and the collectors of switching transistors S21 and S22 are connected to the contact L1.
[0057] The collectors of switching transistors S31 and S32 are connected to the copper busbar 10 on the AC output side, and the emitters of switching transistors S31 and S32 are connected to the contact L2.
[0058] The emitters of switching transistors S41 and S42 are connected to contact N, and the collectors of switching transistors S41 and S42 are connected to contact L2.
[0059] The emitters of switching transistors S51 and S52 are connected to contact O, and the collectors of switching transistors S51 and S52 are connected to contact L1.
[0060] The emitters of switching transistors S61 and S62 are connected to contact L2, and the collectors of switching transistors S61 and S62 are connected to contact O.
[0061] Figure 8 middle:
[0062] X121 is the equivalent RL parameter of the line from the lower end of the switch S21 to the output point (contact L), and X131 is the equivalent RL parameter of the line from the upper end of the switch S31 to the output point. In order to ensure the consistency of their parameters, the RL parameters of X121 and X131 should be the same.
[0063] X122 is the equivalent RL parameter of the line from the lower end of switch S22 to the output point, and X132 is the equivalent RL parameter of the line from the upper end of switch S32 to the output point. To ensure the consistency of their parameters, the RL parameters of X122 and X132 should be the same.
[0064] X51 is the equivalent RL parameter of the circuit from the lower end of switch S51 to the neutral point, and X61 is the equivalent RL parameter of the circuit from the upper end of switch S61 to the neutral point (contact O). To ensure the consistency of their parameters, the RL parameters of X51 and X61 should be the same.
[0065] X52 is the equivalent RL parameter of the line from the lower end of switch S52 to the neutral point, and X62 is the equivalent RL parameter of the line from the upper end of switch S62 to the neutral point. In order to ensure the consistency of their parameters, the RL parameters of X52 and X62 should be the same.
[0066] X11 is the equivalent RL parameter of the line from the lower end of switch S11 to contact L1, X151 is the equivalent RL parameter of the line from the upper end of switch S51 to contact L1, and X21 is the equivalent RL parameter of the line from the upper end of switch S21 to contact L1. To ensure the consistency of their parameters, the RL parameters of X11, X151 and X21 should be the same.
[0067] X12 is the equivalent RL parameter of the line from the lower end of switch S12 to contact L1, X152 is the equivalent RL parameter of the line from the upper end of switch S52 to contact L1, and X22 is the equivalent RL parameter of the line from the upper end of switch S22 to contact L1. To ensure the consistency of their parameters, the RL parameters of X12, X152 and X22 should be the same.
[0068] X161 is the equivalent RL parameter of the line from the lower end of switch S61 to contact L2, X41 is the equivalent RL parameter of the line from the upper end of switch S41 to contact L2, and X31 is the equivalent RL parameter of the line from the lower end of switch S31 to contact L2. To ensure the consistency of their parameters, the RL parameters of X161, X41 and X31 should be the same.
[0069] X162 is the equivalent RL parameter of the circuit from the lower end of switch S62 to contact L2, X42 is the equivalent RL parameter of the circuit from the upper end of switch S42 to contact L2, and X32 is the equivalent RL parameter of the circuit from the lower end of switch S32 to contact L2. To ensure the consistency of their parameters, the RL parameters of X162, X42 and X32 should be the same.
[0070] To ensure uniform flow among the bridge arm units, the parameter values of corresponding components in each bridge arm should be kept consistent.
[0071] The 12 IGBT modules 2 share a single heat sink. The heat sink provides uniform heat dissipation and can provide the 12 IGBT modules 2 with the same heat dissipation conditions, which strengthens the thermal coupling between the devices and ensures that the junction temperature of the 12 IGBT modules is consistent during operation. Under this condition, the symmetrical layout of the 12 IGBT modules and the symmetrical layout of the first stacked busbar achieve the same values for X121, X131, X122, and X132; X51, X61, X52, and X62; X11, X151, X21, X12, X152, and X22; X41, X161, X31, X42, X162, and X32; and X111, X112, X141, and X142.
[0072] like Figure 8 As shown, the AC output section is via Figure 7 The symmetrical AC output side copper busbar 10 shown in the figure gathers the currents of the two branches i1 and i2 into the total circuit i0, thereby ensuring the consistency of the impedance parameters of the two AC branches X171 to X172.
[0073] Point O is the neutral point. The two supporting capacitors are of the same type. To ensure equal voltage division of the supporting capacitors, the second stacked busbar adopts a symmetrical layout, achieving consistent values for X71, X72, X81, and X82. Similarly, the impedance parameters X91, X92, X101, and X102 on the absorption capacitor line are also consistent.
[0074] Figure 8 In the complementary IGBT switch, (S11, S12) and (S51, S52) are complementary in conduction, (S61, S62) and (S41, S42) are complementary in conduction, and (S21, S22) and (S31, S32) are complementary in conduction. In the complementary IGBT switch, the BUSBAR structure adopts an overlapping loop design, and the forward current path and the freewheeling current path basically coincide in the same plane. Because the current directions are opposite, the inductance of the commutation loop is canceled and reduced through coupling.
[0075] Finally, it should be noted that the above description is only a preferred embodiment of this application and is not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. An ANPC power module with IGBT devices directly connected in parallel, characterized in that, include: The system comprises a heat sink (1), an IGBT module (2), a first support frame (3), a fan (4), a first stacked busbar (5), an absorption capacitor (7), a support capacitor (8), a second stacked busbar (9), and an AC output side copper busbar (10). The IGBT module (2) consists of twelve modules arranged in four columns and three rows on the heat sink (1). A fan (4) is installed at each column of IGBT modules (2). An absorption capacitor (7) is installed at the top of each column of IGBT modules (2). Two identical support capacitors (8) are installed at the bottom of the first support frame (3). The second stacked busbar (9) connects the fan (4), the first stacked busbar (5), and the support capacitors (8). The first stacked busbar (5) is also connected to an AC output side copper busbar (10) at the end closest to the fan (4). The first stacked busbar, the second stacked busbar, and the AC output side copper busbar are arranged symmetrically. The twelve IGBT modules (2) are arranged symmetrically and divided into three groups of complementary IGBT switches. Their BUSBAR structure adopts an overlapping loop design, and the forward current path and the freewheeling current path basically overlap in the same plane. The twelve IGBT modules (2) are divided into six groups in parallel, and connected by the first stacked busbar (5) to form a bridge arm. The parameter values of the corresponding components in each bridge arm are kept consistent.
2. The ANPC power module with IGBT devices directly connected in parallel according to claim 1, characterized in that, The first stacked busbar (5) includes contact O, contact P, contact N, contact L1, contact L2 and contact L.
3. The ANPC power module with IGBT devices directly connected in parallel according to claim 2, characterized in that, The second stacked busbar (9) includes contact O, contact P and contact N.
4. An ANPC power module with IGBT devices directly connected in parallel according to claim 3, characterized in that, The power module circuit includes an IGBT module (2), an absorption capacitor (7), and a support capacitor (8). The IGBT module (2) includes switching transistors S11, S12, S21, S22, S31, S32, S41, S42, S51, S52, S61, and S62. Switches S11 and S12 are connected in parallel, S21 and S22 are connected in parallel, S31 and S32 are connected in parallel, S41 and S42 are connected in parallel, S51 and S52 are connected in parallel, and S61 and S62 are connected in parallel.
5. An ANPC power module with IGBT devices directly connected in parallel according to claim 4, characterized in that, The collectors of switching transistors S11 and S12 are connected to contact P, and the emitters of switching transistors S11 and S12 are connected to contact L1. The emitters of switching transistors S21 and S22 are connected to the copper busbar (10) on the AC output side, and the collectors of switching transistors S21 and S22 are connected to the contact L1. The collectors of switching transistors S31 and S32 are connected to the copper busbar (10) on the AC output side, and the emitters of switching transistors S31 and S32 are connected to the contact L2. The emitters of switching transistors S41 and S42 are connected to contact N, and the collectors of switching transistors S41 and S42 are connected to contact L2. The emitters of switching transistors S51 and S52 are connected to contact O, and the collectors of switching transistors S51 and S52 are connected to contact L1. The emitters of switching transistors S61 and S62 are connected to contact L2, and the collectors of switching transistors S61 and S62 are connected to contact O.
6. An ANPC power module with IGBT devices directly connected in parallel according to claim 4, characterized in that, The absorption capacitor (7) includes CS1, CS2, CS3 and CS4. One end of CS1 is connected to one end of CS2, and the other end of CS1 is connected to contact point P. The other end of CS2 is connected to contact point O. One end of CS3 is connected to one end of CS4, and the other end of CS4 is connected to contact point N. The other end of CS3 is connected to contact point O.
7. An ANPC power module with IGBT devices directly connected in parallel according to claim 4, characterized in that, The supporting capacitor (8) includes C1 and C2. The two ends of C1 are connected to contact point P and contact point O, respectively, and the two ends of C2 are connected to contact point O and contact point N, respectively.
8. An ANPC power module with IGBT devices directly connected in parallel according to claim 5, characterized in that, The equivalent RL parameter from the lower end of switch S21 to contact L is the same as the equivalent RL parameter from the upper end of switch S31 to contact L. The equivalent RL parameter from the lower end of switch S22 to contact L is the same as the equivalent RL parameter from the upper end of switch S32 to contact L. The equivalent RL parameter from the lower end of switch S51 to contact O is the same as the equivalent RL parameter from the upper end of switch S61 to contact O. The equivalent RL parameter from the lower end of switch S52 to contact O is the same as the equivalent RL parameter from the upper end of switch S62 to contact O. The equivalent RL parameters of the circuit from the lower end of switch S11 to contact L1, the equivalent RL parameters of the circuit from the upper end of switch S51 to contact L1, and the equivalent RL parameters of the circuit from the upper end of switch S21 to contact L1 are the same. The equivalent RL parameters of the circuit from the lower end of switch S12 to contact L1, the equivalent RL parameters of the circuit from the upper end of switch S52 to contact L1, and the equivalent RL parameters of the circuit from the upper end of switch S22 to contact L1 are the same. The equivalent RL parameters of the circuit from the lower end of switch S61 to contact L2, the equivalent RL parameters of the circuit from the upper end of switch S41 to contact L2, and the equivalent RL parameters of the circuit from the lower end of switch S31 to contact L2 are the same. The equivalent RL parameters of the circuit from the lower end of switch S62 to contact L2, the equivalent RL parameters of the circuit from the upper end of switch S42 to contact L2, and the equivalent RL parameters of the circuit from the lower end of switch S32 to contact L2 are the same.
Citation Information
Patent Citations
Current-equalizing parallel IGBT module assembly
CN107733246A
Three-level IGBT parallel current sharing structure
CN220325517U