Explosion-proof low-inductance composite busbar structure

Abstract

The utility model discloses an explosion-proof low-inductance composite busbar structure, which belongs to the technical field of composite busbars and comprises a capacitor side composite busbar and a voltage string side composite busbar which are butted with each other. The capacitor-side composite busbar comprises a capacitor-side composite busbar first electrode plate, a first insulating plate and a capacitor-side composite busbar second electrode plate which are arranged in sequence; second insulating plates are fixed at the lower ends of the capacitor-side composite busbar first electrode plate, the first insulating plate and the capacitor-side composite busbar second electrode plate; the voltage string side composite busbar comprises a voltage string side first electrode plate, a third insulating plate and a voltage string side second electrode plate which are arranged in sequence; fourth insulating plates are fixed at the lower ends of the voltage string side first electrode plate, the third insulating plate and the voltage string side second electrode plate; and the second insulating plate is fixedly connected with the fourth insulating plate. The capacitor side composite busbar first electrode plate, the capacitor side composite busbar second electrode plate, the voltage string side first electrode plate and the voltage string side second electrode plate are parallel, electromagnetic fields offset each other, and stray inductance is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of composite busbars, and particularly relates to an explosion-proof low-inductance composite busbar structure. Background Technique

[0002] With the development of power electronics technology, the power density of IGBT (Insulated Gate Bipolar Transistor) modules is getting higher and higher, and the turn-on and turn-off performance is getting better and better. With the continuous increase of the voltage level and current level of IGBT devices, rapid turn-on and turn-off will cause a large current change rate di / dt in the IGBT, and the parasitic inductance in the circuit will form a high voltage spike at both ends of the IGBT device. These voltage spikes will damage the IGBT device and even cause an explosion in severe cases, which is not conducive to the long-term reliable operation of the IGBT. At the same time, when a 4.5kv, 5ka power device explodes due to bypass refusal, the explosion energy is large, the device housing ruptures, and various flying objects fly out, causing a large number of safety risks.

[0003] To minimize this hazard as much as possible, composite busbars are usually used to connect electrical components. Composite busbars have advantages such as low parasitic inductance and low partial discharge rate. Using a composite busbar structure for circuit connection in the power unit loop can effectively reduce the parasitic inductance and partial discharge rate in the circuit, and at the same time can reduce the installation space. However, in the past, the rated voltage and current values of the flexible DC converter valve power module were low, and the energy generated during an accidental explosion was low and would not cause great damage. Therefore, the structural optimization design of the composite busbar mainly focused on cost reduction. However, with the use of high-power devices, the explosion energy is too large, causing great damage to the module, and the demand for the explosion-proof ability of the composite busbar has increased. Summary of the Invention

[0004] The utility model provides an explosion-proof low-inductance composite busbar structure, which can significantly reduce the stray inductance of the loop and improve the explosion-proof ability of the composite busbar.

[0005] To achieve the above object, an explosion-proof low-inductance composite busbar structure described in the utility model includes a butt-jointed capacitor-side composite busbar and a voltage-series side composite busbar; the capacitor-side composite busbar includes a capacitor-side composite busbar first electrode plate, a first insulating plate, and a capacitor-side composite busbar second electrode plate arranged in sequence, and a second insulating plate is fixed to the lower ends of the capacitor-side composite busbar first electrode plate, the first insulating plate, and the capacitor-side composite busbar second electrode plate;

[0006] The voltage-series side composite busbar includes a voltage-series side first electrode plate, a third insulating plate, and a voltage-series side second electrode plate arranged in sequence, and a fourth insulating plate is fixed to the lower ends of the voltage-series side first electrode plate, the third insulating plate, and the voltage-series side second electrode plate;

[0007] The first electrode plate of the capacitor-side composite busbar, the second electrode plate of the capacitor-side composite busbar, the first electrode plate of the press-string side, and the second electrode plate of the press-string side are parallel to each other;

[0008] The second insulating plate and the fourth insulating plate are fixedly connected.

[0009] Furthermore, the first electrode plate and the second electrode plate of the capacitor-side composite busbar have the same structure and size, and both include a copper bar. The copper bar is coated with an insulating film, and a number of copper columns and vias arranged in an array are fixed on the copper bar, and an insulating ring is installed on the via.

[0010] Furthermore, the first electrode plate of the press-string side and the second electrode plate of the press-string side have the same structure, and both include a copper bar. The copper bar is coated with an insulating film, and a number of copper columns and vias arranged in an array are fixed on the copper bar, and an insulating ring is installed on the via.

[0011] Furthermore, the materials of the copper bar and the copper column are red copper.

[0012] Furthermore, the insulating material used for the insulating film is polyester film PET.

[0013] Furthermore, the surface roughness of the overlapping surface between the copper column and the water-cooled plate is less than 1 μm.

[0014] Furthermore, the capacitor-side composite busbar and the capacitor have the same width, and the press-string side composite busbar and the press-fit assembly of the IGBT have the same width.

[0015] Furthermore, a negative terminal and a positive terminal are fixed on the upper part of the capacitor-side composite busbar, and a grounding terminal is fixed at the lower end.

[0016] Furthermore, both the negative terminal and the positive terminal are L-shaped.

[0017] Furthermore, threaded holes are provided on the second insulating plate and the fourth insulating plate, and the second insulating plate and the fourth insulating plate are connected by bolts.

[0018] Compared with the prior art, the present utility model has at least the following beneficial technical effects:

[0019] 1) The composite busbar is respectively connected to the capacitor and the IGBT component press-string through the U-shaped circuits formed by the capacitor-side composite busbar and the press-string side composite busbar. The first electrode plate of the capacitor-side composite busbar, the second electrode plate of the capacitor-side composite busbar, the first electrode plate of the press-string side, and the second electrode plate of the press-string side are completely parallel, and the currents are reversely parallel, so the electromagnetic fields cancel each other out, reducing the stray inductance and reducing the voltage spike of the IGBT device. The stray inductance of the composite busbar measured by simulation is only 20.8 nH.

[0020] 2) The composite busbar has good explosion-proof ability. With a reasonable structural design, it ensures that the bolts do not fall off during the explosion, enabling the circuit to still exist after the explosion, thus improving the overall reliability of the power module. During operation, the composite busbar on the crimping component side fully wraps the rear of the crimping component. When the IGBT explodes, the composite busbar can block the flying debris from flying out. The connection direction of the composite busbar on the series connection side with the water-cooled radiator bolts is parallel to the explosion impact direction, so the bolts are not subject to shear force and do not fall off. The connection between the crimping component and the composite busbar on the series connection side is tight, and the current loop remains intact. The explosion impact on the capacitor side is smaller and there is no damage. Therefore, this composite busbar has excellent explosion-proof ability and ensures the existence of the current loop, meeting the requirements of practical engineering applications.

[0021] 3) The composite busbar has a simple structure and low processing difficulty; it has good electrical conductivity through high-precision copper column connection. Full consideration is given to insulation protection, and the creepage distance requirements are met at all angles. Description of the Drawings

[0022] Figure 1 is the overall structure schematic diagram;

[0023] Figure 2 is the exploded view of the composite busbar on the capacitor side;

[0024] Figure 3 is the exploded view of the composite busbar on the series connection side;

[0025] Figure 4 is the exploded view of the first electrode plate of the capacitor side busbar;

[0026] Figure 5 is the exploded view of the second electrode plate of the capacitor side busbar;

[0027] Figure 6 is the exploded view of the structure of the first electrode plate on the series connection side;

[0028] Figure 7 is the exploded view of the structure of the second electrode plate on the series connection side;

[0029] Figure 8 is the installation schematic diagram of the composite busbar with the capacitor and the crimping component;

[0030] Figure 9 is the current path diagram of the composite busbar.

[0031] In the attached drawings: 1. The first electrode plate of the capacitor-side composite busbar; 2. The first insulating plate; 3. The second electrode plate of the capacitor-side composite busbar; 4. The second insulating plate; 5. The first electrode plate on the press-string side; 6. The third insulating plate; 7. The second electrode plate on the press-string side; 8. The fourth insulating plate; 101. The first insulating film; 102. The first insulating ring; 103. The first copper column; 104. The first copper busbar; 105. The second insulating film; 301. The third insulating film; 302. The second copper column; 303. The second copper busbar; 304. The fourth insulating film; 501. The fifth insulating film; 502. The third copper column; 503. The third copper busbar; 504. The second insulating ring; 505. The sixth insulating film; 701. The seventh insulating film; 702. The fourth copper column; 703. The fourth copper busbar; 704. The eighth insulating film; 9. The negative terminal; 10. The positive terminal; 11. The grounding terminal; 12. The via hole; 100. The capacitor-side composite busbar; 200. The press-string side composite busbar; 300. The capacitor; 400. The IGBT press-fitting assembly. Detailed implementation manners

[0032] The present utility model will be described in detail below with reference to the attached drawings and specific implementation manners.

[0033] In order to enable those skilled in the art to better understand the technical solutions in the present utility model, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the attached drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

[0034] It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or there can also be another intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be another intermediate element at the same time. The terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. used herein indicate the orientation or positional relationship based on the orientation or positional relationship shown in the attached drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation to the present utility model.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this utility model belongs. The terms used in the specification of this utility model are only for the purpose of describing specific embodiments and are not intended to limit this utility model. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0036] Embodiment 1

[0037] This embodiment provides a composite busbar with explosion-proof and low stray inductance, which improves the explosion-proof ability of the composite busbar through structural design, improves the reliability of long-term operation of IGBTs, and the composite busbar has passed both electrodynamic simulation verification and explosion-proof experiment verification.

[0038] Referring to Figures 1 to 8 , a composite busbar with explosion-proof and low stray inductance, is integrally U-shaped, and includes a capacitor-side composite busbar 100 and a voltage-series side composite busbar 200. The capacitor-side composite busbar 100 and the voltage-series side composite busbar 200 are arranged opposite to each other and fixedly connected.

[0039] The capacitor-side composite busbar includes a capacitor-side composite busbar first electrode plate 1, a first insulating plate 2, and a capacitor-side composite busbar second electrode plate 3 that are fixedly connected in sequence. Second insulating plates 4 are fixedly arranged at the lower ends of the capacitor-side composite busbar first electrode plate 1 and the capacitor-side composite busbar second electrode plate 3, and a plurality of first threaded holes are formed in the second insulating plates 4; the second insulating plates 4 are perpendicular to the capacitor-side composite busbar first electrode plate 1, the first insulating plate 2, and the capacitor-side composite busbar second electrode plate 3.

[0040] The voltage-series side composite busbar includes a voltage-series side first electrode plate 5, a third insulating plate 6, and a voltage-series side second electrode plate 7 that are fixedly connected in sequence. Fourth insulating plates 8 are fixedly arranged at the lower ends of the voltage-series side first electrode plate 5 and the voltage-series side second electrode plate 7. A plurality of second threaded holes are formed in the fourth insulating plates 8; the fourth insulating plates 8 are perpendicular to the voltage-series side first electrode plate 5, the third insulating plate 6, and the voltage-series side second electrode plate 7.

[0041] A negative terminal 9 is fixedly arranged on the upper part of the capacitor-side composite busbar first electrode plate, and a positive terminal 10 is fixedly arranged at the upper end of the second capacitor-side composite busbar electrode plate. Four press riveting nuts are configured for power module wiring. At the same time, the terminals are bent to facilitate cable installation. A grounding terminal 11 is fixedly connected to the bent part at the lower end of the capacitor-side composite busbar first electrode plate, and a nut is riveted for easy installation.

[0042] The first electrode plate 1 of the composite busbar on the capacitor side is composed of a first insulating film 101, a first insulating ring 102, a first copper column 103, a first copper busbar 104, and a second insulating film 105. The first insulating film 101 and the second insulating film 105 are respectively wrapped on both sides of the first copper busbar 104. A number of first copper columns 103 and vias 12 arranged in an array are fixed on the first copper busbar 104, and a first insulating ring 102 is installed on the via 12.

[0043] The second electrode plate 2 of the composite busbar on the capacitor side is composed of a third insulating film 301, a second copper column 302, a first insulating ring 102, a second copper busbar 303, and a fourth insulating film 304. The third insulating film 301 and the fourth insulating film 304 are respectively wrapped on both sides of the second copper busbar 303. A number of second copper columns 302 and vias 12 arranged in an array are fixed on the second copper busbar 303, and a first insulating ring 102 is installed on the via 12.

[0044] The first electrode plate 5 on the voltage series side is composed of a fifth insulating film 501, a third copper column 502, a third copper busbar 503, a second insulating ring 504, and a sixth insulating film 505. The fifth insulating film 501 and the sixth insulating film 505 are respectively wrapped on both sides of the third copper busbar 503. A number of third copper columns 502 and vias 12 arranged in an array are fixed on the third copper busbar 503, and a second insulating ring 504 is installed on the via 12.

[0045] The second electrode plate 7 on the voltage series side is composed of a seventh insulating film 701, a fourth copper column 702, a fourth copper busbar 703, a second insulating ring 504, and an eighth insulating film 704. The seventh insulating film 701 and the eighth insulating film 704 are respectively wrapped on both sides of the fourth copper busbar 703. A number of fourth copper columns 702 and vias 12 arranged in an array are fixed on the third copper busbar 503, and a second insulating ring 504 is installed on the via 12.

[0046] During assembly, the composite busbar on the capacitor side and the composite busbar on the voltage series side are butted, and bolts are passed through the first threaded hole and the second threaded hole and tightened. The composite busbar is respectively connected to the capacitor 300 and the IGBT crimping assembly 400 through both sides of the U-shaped loop. The first electrode plate 1 of the composite busbar on the capacitor side, the second electrode plate 3 of the composite busbar on the capacitor side, the first electrode plate 5 on the voltage series side, and the second electrode plate 7 on the voltage series side are completely parallel, and the currents are reversely connected in parallel. Therefore, the electromagnetic fields cancel each other out, reducing the stray inductance. The stray inductance of the composite busbar obtained by simulation is only 20.8 nH.

[0047] Preferably, all copper busbars and copper columns are made of oxygen-free copper, which has good electrical performance. Among them, the conductivity @20°C = 59.6×10 6 S / m, the resistivity @20°C = 0.018 Ω·mm 2 / m, and the density is 7.83 g / cm 3 .

[0048] Preferably, the insulating materials used for the first to eighth insulating films are polyester film PET materials. Polyester film PET materials have good electrical properties, chemical corrosion resistance, low hygroscopicity, and low cost. For the insulating ring and insulating plate, epoxy glass cloth laminate FR-4 is selected, which has relatively high mechanical strength at medium temperature and stable electrical properties under high humidity.

[0049] Preferably, the composite busbar is connected to the capacitor and the water-cooled radiator through high-precision copper posts to increase the contact area and accuracy. The surface roughness of the overlapping surface between the copper post and the water-cooled plate is less than 1μm, and the contact resistance between the two is low, effectively reducing the loss of the current loop.

[0050] Preferably, the width of the composite busbar is the same as the width of the capacitor and the width of the crimping component of the IGBT respectively. On the one hand, it increases the current flow area, thereby reducing the thickness of the copper busbar; on the other hand, it improves the explosion-proof ability of the power module, and the composite busbar blocks the flying debris during an explosion.

[0051] Preferably, at the connection between the composite busbar on the capacitor side and the composite busbar on the series capacitor side, through the insulating plate, insulating film and air gap, a creepage distance of 83mm is left, meeting the requirement of 14mm / kV (14 * 4.5 = 63mm) specified in the standard. At the same time, it meets the requirement that the creepage distance is sufficient when there is partial skew during the installation process. The air gap is the distance between the composite busbar on the capacitor side and the composite busbar on the series capacitor side.

[0052] In terms of explosion-proof ability, the composite busbar tightly wraps the series capacitor and the capacitor, reducing the flying debris during the explosion of the power module. And the bolt connection direction is the same as the explosion impact direction. During the explosion-proof experiment, the shear force on the bolt is small, and the bolt connection is stable. This makes the circuit still exist after the explosion, improving the overall reliability of the power module.

[0053] Figure 9 This is the current path of the composite busbar. The current passes through the crimping component, flows from the water-cooled radiator to the busbar on the crimping component side along the solid arrow and into one side of the capacitor, and then returns to the crimping component along the dotted arrow from the other side after passing through the capacitor. The current paths of the positive and negative currents completely overlap, and the parasitic magnetic fields cancel each other out, reducing the stray inductance of the busbar.

[0054] Embodiment 2

[0055] To cope with the working scenarios of high voltage and large current of the 4.5kV, 5kA insulated gate bipolar transistor (IGBT) in the circuit, this embodiment provides a composite busbar with low stray inductance. On the basis of optimizing the lap joint method of the two-sided busbar in Embodiment 1, low-inductance design is carried out from the perspectives of optimizing the interlayer distance, copper busbar thickness, terminal length, current path, insulating material, and metal material selection. Among them, the interlayer distance is set to 5mm, the copper busbar thickness is set to 4mm, the terminal length is 25mm, and the terminal bending is convenient for wiring.

[0056] The composite busbar is adapted to IGBT power devices with 4.5 kV and 5 kA. Since the voltage is high and the current is large, the positive and negative electrodes respectively wrap copper bars with insulating films, and an insulating board is arranged in the middle to improve the insulation protection ability. The via hole 12 between the positive and negative electrodes provides insulation protection by setting an insulating ring.

[0057] The term "comprising" in describing a combination shall include the identified elements, components, parts or steps and other elements, components, parts or steps that do not substantially affect the basic novel features of the combination. Using the terms "comprising" or "including" to describe the combination of elements, components, parts or steps herein also contemplates embodiments consisting essentially of these elements, components, parts or steps. By using the term "may" herein, it is intended to indicate that any attribute described as "may" included is optional.

[0058] Multiple elements, components, parts or steps can be provided by a single integrated element, component, part or step. Alternatively, a single integrated element, component, part or step can be divided into separate multiple elements, components, parts or steps. The disclosure of "a" or "an" used to describe an element, component, part or step does not mean to exclude other elements, components, parts or steps.

[0059] It should be understood that the above description is for illustrative purposes and not for limitation. By reading the above description, many embodiments and many applications other than the provided examples will be obvious to those skilled in the art. Therefore, the scope of this teaching should not be determined with reference to the above description, but should be determined with reference to the full scope of the foregoing claims and the equivalents of these claims. For the sake of completeness, all articles and references including the disclosures of patent applications and publications are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended to abandon such subject matter, nor should the applicant be regarded as not considering such subject matter as part of the disclosed utility model subject matter.

Claims

1. An explosion-proof low-inductance composite busbar structure, characterized in that: It comprises a capacitor-side composite busbar (100) and a voltage-string-side composite busbar (200) that are butt-jointed; The capacitor-side composite busbar (100) comprises a capacitor-side composite busbar first electrode plate (1), a first insulating plate (2) and a capacitor-side composite busbar second electrode plate (3) which are arranged in sequence, and a second insulating plate (4) is fixed to the lower ends of the capacitor-side composite busbar first electrode plate (1), the first insulating plate (2) and the capacitor-side composite busbar second electrode plate (3); The composite busbar on the pressure string side comprises a first pressure string side electrode plate (5), a third insulating plate (6) and a second pressure string side electrode plate (7) which are arranged in sequence, and a fourth insulating plate (8) is fixed to the lower ends of the first pressure string side electrode plate (5), the third insulating plate (6) and the second pressure string side electrode plate (7); The first electrode plate (1) of the capacitor-side composite busbar, the second electrode plate (3) of the capacitor-side composite busbar, the first electrode plate (5) of the voltage string side, and the second electrode plate (7) of the voltage string side are parallel to each other; The second insulating plate (4) and the fourth insulating plate (8) are fixedly connected.

2. The explosion-proof low-inductance composite busbar structure according to claim 1, characterized in that: The capacitor-side composite busbar first electrode plate (1) and the capacitor-side composite busbar second electrode plate (3) have the same structure and size, and both comprise a copper busbar, the copper busbar being coated with an insulating film, a plurality of copper columns and vias (12) arranged in an array being fixed on the copper busbar, and an insulating ring being installed on the vias (12).

3. The explosion-proof low-inductance composite busbar structure according to claim 1, characterized in that: The first electrode plate (5) on the string side and the second electrode plate (7) on the string side have the same structure, both comprising a copper bar, the copper bar being coated with an insulating film, a plurality of copper columns and vias (12) arranged in an array being fixed on the copper bar, and an insulating ring being installed on the vias (12).

4. An explosion-proof low-inductance composite busbar structure according to claim 2 or 3, characterized in that: The copper bus and the copper column are made of red copper.

5. An explosion-proof low-inductance composite busbar structure according to claim 2 or 3, characterized in that: The insulating material used by the insulating film is polyester film PET.

6. The explosion-proof low-inductance composite busbar structure according to claim 3, characterized in that: The surface roughness of the overlapping surface between the copper column and the water cooling plate is less than 1 μm.

7. The explosion-proof low-inductance composite busbar structure according to claim 1, characterized in that: The capacitor-side composite busbar (100) has the same width as the capacitor, and the string-voltage-side composite busbar (200) has the same width as the IGBT crimping assembly.

8. The explosion-proof low-inductance composite busbar structure according to claim 1, characterized in that: The capacitor-side composite busbar (100) has a negative electrode connection terminal (9) and a positive electrode connection terminal (10) fixed to its upper portion, and a ground connection terminal (11) fixed to its lower end.

9. The explosion-proof low-inductance composite busbar structure according to claim 8, characterized in that: The negative electrode terminal (9) and the positive electrode terminal (10) are both L-shaped.

10. The explosion-proof low-inductance composite busbar structure according to claim 1, characterized in that: The second insulating plate (4) and the fourth insulating plate (8) are provided with threaded holes, and the second insulating plate (4) and the fourth insulating plate (8) are connected by bolts.

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