阅读说明：本技术 用于功率模块的低杂散电感母排结构 (Low stray inductance busbar structure for power module ) 是由 毛先叶 孙靖雅 王长城 于 2020-12-28 设计创作，主要内容包括：本发明公开了一种用于功率模块的低杂散电感母排结构,本结构包括散热器、覆铜陶瓷基板、晶圆、塑壳、正负母排和灌封胶,覆铜陶瓷基板焊接在散热器上,晶圆焊接在覆铜陶瓷基板上,塑壳固定在散热器上,并且正母排和负母排通过灌封胶封装于塑壳内,正母排和负母排通过超声键合固定在覆铜陶瓷基板上,并且形成功率模块的电气回路,通过灌封胶进行灌封保证晶圆以及正负母排之间的电气间隙,正母排和负母排的叠层部分在塑壳内并从塑壳内延伸超出塑壳表面呈上下间隔叠层布置。本结构有效减少由杂散电感引起的浪涌电压,避免功率模块被击穿的危险,提高功率模块的抗振性能,确保功率模块的开关特性以及电机驱动控制的可靠性。(The invention discloses a low stray inductance busbar structure for a power module, which comprises a radiator, a copper-clad ceramic substrate, a wafer, a plastic shell, a positive busbar, a negative busbar and a pouring sealant, wherein the copper-clad ceramic substrate is welded on the radiator, the wafer is welded on the copper-clad ceramic substrate, the plastic shell is fixed on the radiator, the positive busbar and the negative busbar are encapsulated in the plastic shell through the pouring sealant, the positive busbar and the negative busbar are fixed on the copper-clad ceramic substrate through ultrasonic bonding and form an electric loop of the power module, the pouring sealant is used for filling and sealing to ensure an electric gap between the wafer and the positive busbar and the negative busbar, and the laminated parts of the positive busbar and the negative busbar extend in the plastic shell and exceed the surface of the plastic shell to be arranged in. The structure effectively reduces surge voltage caused by stray inductance, avoids the danger of breakdown of the power module, improves the vibration resistance of the power module, and ensures the switching characteristic of the power module and the reliability of motor drive control.)

1. The utility model provides a female structure of arranging of low stray inductance for power module, includes the radiator, covers copper ceramic substrate, wafer, moulds the shell, just female arranging, female arranging of burden and casting glue, cover copper ceramic substrate welding on the radiator, the wafer welding cover on the copper ceramic substrate, mould the shell and fix on the radiator, and just female arranging and the female arranging of burden pass through the casting glue encapsulate in mould the shell, just female arranging and the female arranging of burden are fixed on covering copper ceramic substrate through the ultrasonic bonding to form power module's electrical circuit, through the casting glue carries out the embedment and guarantees wafer and the female electrical clearance of arranging of positive and negative, its characterized in that: the laminated part of the positive busbar and the negative busbar extends in the plastic shell and extends out of the surface of the plastic shell from the inside of the plastic shell.

2. The low stray inductance busbar structure for power modules according to claim 1, wherein: the length of the laminated part of the positive busbar and the negative busbar extending out of the surface of the plastic shell from the inside of the plastic shell is more than or equal to 0.

3. The low stray inductance busbar structure for a power module according to claim 1 or 2, wherein: the positive busbar and the negative busbar are arranged in a parallel and laminated mode and extend to the copper-clad ceramic substrate, the positive busbar is arranged on the upper portion and the negative busbar is arranged on the lower portion or the negative busbar is arranged on the upper portion and the positive busbar is arranged on the lower portion in a laminated mode, and the distance between the positive busbar and the negative busbar is smaller than or equal to 3 mm.

4. The low stray inductance busbar structure for power modules according to claim 3, wherein: the difference between the width and the length of the laminated part of the positive busbar and the negative busbar is more than or equal to 0.

5. The low stray inductance busbar structure for power modules according to claim 3, wherein: the encapsulating surface of the encapsulating adhesive is at least higher than the lower positive busbar or the lower negative busbar which are arranged in a laminated manner.

6. The low stray inductance busbar structure for power modules according to claim 3, wherein: the pouring sealant is silica gel or epoxy resin.

Technical Field

The invention relates to the technical field of motor control, in particular to a low stray inductance busbar structure for a power module.

Background

In a three-phase alternating current motor driving system, high-frequency carrier waves are generally adopted to drive a power semiconductor device to open and close a tube at a high speed, surge voltage proportional to the size of stray inductance of a motor driving main loop is loaded on the power semiconductor device, and when the surge voltage is too large, the power semiconductor device is possibly broken down and damaged. Therefore, the surge voltage can be reduced by reducing the loop stray inductance to the maximum extent so as to ensure the normal operation of the power semiconductor device. Particularly, in the field of new energy automobile motor controllers, the application trend of SiC and GaN power modules in new energy automobiles is more and more obvious, and the requirement on the driving frequency of an on-off tube is higher and higher, so that how to reduce the stray inductance of a power module busbar is an important research topic

Typically, the surge voltage is calculated as equation (1):

as shown in fig. 1 and 2, a general three-phase ac motor driving main circuit structure includes a heat sink 4, a copper-clad ceramic substrate 5, wafers 6, a plastic shell 3, a positive busbar 1, a negative busbar 2, and a potting adhesive 7, where the copper-clad ceramic substrate 5 is welded on the heat sink 4, the wafers 6 are welded on the copper-clad ceramic substrate 5, the plastic shell 3 is fixed on the heat sink 4, the positive busbar 1 and the negative busbar 2 are fixed on the copper-clad ceramic substrate 5 through ultrasonic bonding to form an electrical circuit of a power module 6, and then an electrical gap between the wafer and the busbar is ensured through the potting adhesive 7, where the wafer may be a power chip such as Si, SiC, GaN, etc. In the main circuit structure, the positive and negative busbars are injected into the plastic shell 3 and are arranged up and down, the L2 area shown in fig. 2 is a lamination arrangement area of the positive busbar 1 and the negative busbar 2, the L1 area is an area where the plastic shell 3 is insulated and wrapped by the positive and negative busbars, and the L3 area is a staggered non-lamination area of the positive and negative busbars. Because the female 1 of just arranging and the female 2 of arranging of plastic casing 3 need be wrapped up, and just female arranging 1 of just arranging 2 dislocation arrangement with the burden extends plastic casing 3 and covers the copper layer of copper ceramic substrate 5 different polarity and be connected, consequently the L3 region is regional for non-lamination generally, the regional current loop of L3 can be regarded as the current loop with ground formation, the loop area S that the electric current flowed through this moment is great, it is great also that the a x h in formula 2 is great promptly, according to formula 2 can know, stray inductance L increases, stray inductance seriously influences power module 'S switching characteristic, reduce motor drive control' S reliability.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a low stray inductance busbar structure for a power module, which overcomes the defects of a traditional three-phase alternating current motor driving main loop structure, effectively reduces surge voltage caused by stray inductance, avoids the danger of breakdown of the power module, improves the vibration resistance of the power module, and ensures the switching characteristic of the power module and the reliability of motor driving control.

In order to solve the technical problem, the low stray inductance busbar structure for the power module comprises a radiator, a copper-clad ceramic substrate, a wafer, a plastic shell, a positive busbar, a negative busbar and a pouring sealant, wherein the copper-clad ceramic substrate is welded on the radiator, the wafer is welded on the copper-clad ceramic substrate, the plastic shell is fixed on the radiator, the positive busbar and the negative busbar are packaged in the plastic shell through the pouring sealant, the positive busbar and the negative busbar are fixed on the copper-clad ceramic substrate through ultrasonic bonding and form an electrical loop of the power module, an electrical gap between the wafer and the positive busbar and the negative busbar is guaranteed through the pouring sealant in a pouring mode, and the laminated part of the positive busbar and the negative busbar extends out of the surface of the plastic shell in the plastic shell and extends from the interior of the plastic shell.

Further, the length of the laminated part of the positive busbar and the negative busbar extending out of the surface of the plastic shell from the inside of the plastic shell is more than or equal to 0.

Further, the positive busbar and the negative busbar are arranged in a parallel lamination mode and extend to the copper-clad ceramic substrate, the positive busbar is arranged above and below the negative busbar or the negative busbar is arranged above and below the positive busbar, and the distance between the positive busbar and the negative busbar is smaller than or equal to 3 mm.

Further, the difference between the width and the length of the laminated part of the positive busbar and the negative busbar is more than or equal to 0.

Further, the potting surface of the potting adhesive is at least higher than the lower positive busbar or the lower negative busbar arranged in a laminated manner.

Furthermore, the pouring sealant is silica gel or epoxy resin.

The low stray inductance busbar structure for the power module adopts the technical scheme, namely the structure comprises a radiator, a copper-clad ceramic substrate, a wafer, a plastic shell, a positive busbar, a negative busbar and a pouring sealant, wherein the copper-clad ceramic substrate is welded on the radiator, the wafer is welded on the copper-clad ceramic substrate, the plastic shell is fixed on the radiator, the positive busbar and the negative busbar are packaged in the plastic shell through the pouring sealant, the positive busbar and the negative busbar are fixed on the copper-clad ceramic substrate through ultrasonic bonding and form an electrical loop of the power module, the electrical gap between the wafer and the positive busbar and the negative busbar is ensured through the pouring sealant in a pouring manner, and the laminated part of the positive busbar and the negative busbar extends out of the surface of the plastic shell in the plastic shell and extends out of the surface of the plastic shell. The structure overcomes the defects of a traditional three-phase alternating current motor driving main loop structure, effectively reduces surge voltage caused by stray inductance, avoids the danger that a power module is punctured, improves the vibration resistance of the power module, and ensures the switching characteristic of the power module and the reliability of motor driving control.

Drawings

The invention is described in further detail below with reference to the following figures and embodiments:

FIG. 1 is a schematic diagram of a three-phase AC motor driving main circuit;

FIG. 2 is a view taken along line A-A of FIG. 1;

fig. 3 is a schematic diagram of a low stray inductance busbar structure for a power module according to the present invention;

FIG. 4 is a schematic structural diagram of a negative bus bar arrangement with positive and negative bus bars arranged in a laminated manner;

FIG. 5 is a partial isometric view of the present structure;

FIG. 6 is a schematic plan view of a portion of the present structure;

FIG. 7 is a schematic view of the positive bus arrangement of the positive and negative bus bar lamination arrangement in the present structure;

fig. 8 is a schematic view of a negative bus bar arranged in a positive-negative bus bar lamination in the present structure.

Detailed Description

As shown in fig. 3, the low stray inductance busbar structure for power module of the present invention includes a heat sink 4, a copper-clad ceramic substrate 5, a wafer 6, a plastic housing 3, a positive busbar 1, a negative busbar 2 and a potting compound 7, the copper-clad ceramic substrate 5 is welded on the radiator 4, the wafer 6 is welded on the copper-clad ceramic substrate 5, the plastic shell 3 is fixed on the radiator 4, the positive busbar 1 and the negative busbar 2 are encapsulated in the plastic shell 3 through a pouring sealant 7, the positive busbar 1 and the negative busbar 2 are fixed on a copper-clad ceramic substrate 5 through ultrasonic bonding, and an electric loop of the power module is formed, the wafer 6 and the electric gap between the positive and negative busbars 1 and 2 are ensured by encapsulating through the encapsulating glue 7, the laminated part of the positive busbar 1 and the negative busbar 2 extends in the plastic shell 3 and extends from the interior of the plastic shell 3 to exceed the surface of the plastic shell 3.

Preferably, as shown in fig. 3 and 4, and fig. 5 and 6, the length of the laminated portion of the positive busbar 1 and the negative busbar 2 extending out of the plastic shell 3 is greater than or equal to 0, that is, L4 is greater than or equal to zero in the drawing.

Preferably, as shown in fig. 3, 4, 7 and 8, the positive busbar 1 and the negative busbar 2 are arranged in a parallel lamination manner and extend to the copper-clad ceramic substrate 5, the positive busbar 1 is arranged on the upper side, the negative busbar 2 is arranged on the lower side, or the negative busbar 2 is arranged on the upper side, and the positive busbar 1 is arranged on the lower side, and the distance between the positive busbar 1 and the negative busbar 2 is less than or equal to 3 mm.

Preferably, the difference between the width and the length of the laminated part of the positive busbar 1 and the negative busbar 2 is greater than or equal to 0. The width as well as the length of the laminated part are preferably of the same size.

Preferably, the potting surface of the potting adhesive 7 is at least higher than the lower positive busbar 1 or the lower negative busbar 2 arranged in a laminated manner.

Preferably, the potting adhesive 7 is silica gel or epoxy resin.

The power module internal bus bar terminal stray inductance too big difficult problem is effectively solved to this structure, positive female arranging and negative female arranging are the stromatolite in L2 region and wear out the moulded case and extend to inside the power module, adopt the casting glue to carry out insulating embedment simultaneously, in order to guarantee the electric clearance between positive negative female arranging and the power module, the non-stromatolite region of positive negative female arranging has greatly been reduced, the loop area S that so electric current flowed through reduces, a x h reduces in the formula 2 promptly, according to formula 2 can know, stray inductance L correspondingly reduces, effectively reduce surge voltage, avoid the danger that the power module is punctured, ensure the switching characteristic of power module, the reliability of motor drive control is improved.