CN217694104U

CN217694104U - Single-tube IGBT parallel driver

Info

Publication number: CN217694104U
Application number: CN202220111582.0U
Authority: CN
Inventors: 张传民
Original assignee: Beijing Sword Electric Industrial Co ltd
Current assignee: Beijing Sword Electric Industrial Co ltd
Priority date: 2022-01-17
Filing date: 2022-01-17
Publication date: 2022-10-28
Anticipated expiration: 2032-01-17

Abstract

The utility model relates to a IGBT drive controller field provides a single tube IGBT driver that connects in parallel, aims at solving the current heavy current single tube IGBT driver manufacturing process complicacy, the difficult problem of quality control. This single tube IGBT parallel driver includes: the IGBT module comprises an IGBT chip assembly, a capacitor assembly, a driving plate assembly and a radiator; the capacitor assembly and the driving board assembly are fixedly connected through a laminated busbar, and the IGBT chip assemblies are arranged on two sides of the radiator; the laminated bus bar is provided with jacks and contact pins, electrodes of capacitors in the capacitor assembly are correspondingly assembled and connected with the jacks in the laminated bus bar, and the contact pins on the laminated bus bar are inserted into the corresponding jacks on the driving plate assembly; each IGBT single tube chip in the IGBT chip assembly is clamped to the radiating surfaces on two sides of the radiator through clamp springs, wherein each clamp spring clamps the two IGBT single tube chips to two side surfaces of the radiator respectively. The single-tube IGBT parallel driver is simple to manufacture, easy in quality control and low in comprehensive cost.

Description

Single-tube IGBT parallel driver

Technical Field

The utility model relates to a power device field, in particular to single tube IGBT driver that connects in parallel.

Background

In the electric automobile driver, the single-tube IGBT parallel driver is developed rapidly in the application field of the electric automobile driver due to the advantages of low cost, high power density, easy expansion and the like.

However, most of the structural form processes of large-current single-tube IGBT parallel drivers on the market are a discrete radiator and DBC welding process. After the radiator, the ceramic plate and the single tube IGBT are welded into an independent component, the three components are connected with the driving plate. The DBC welding process needs special welding equipment, and the welding cost is high; in addition, during welding, the pin position degree of a single tube needs to be ensured, and a positioning tool needs to be matched for use; the deformation degree of the welded pins is not easy to control, the assembly is assembled to the box body, and then the assembly is assembled with the drive plate after the assembly is assembled with the copper bar, so that more tolerance is accumulated in the process, the two processes of copper bar assembly and drive plate assembly are very difficult to insert, shaping or auxiliary tools are often needed, even the consistency of product production can be ensured by an automatic production line of people, the manufacturing process is complicated, the quality control is difficult, the structure cost is high, the assembly cost is high, and the equipment investment is large; and has higher requirements on the processing of structural materials and the capacity of structural suppliers

Therefore, a single-tube IGBT driver which is simple to manufacture, easy to control quality, low in comprehensive cost and free of new equipment investment is needed, and the problems that the current high-current single-tube IGBT driver is complex in manufacturing process, difficult to control quality, high in structure cost and equipment investment, high in requirements for production suppliers and increased in supply cost are solved.

SUMMERY OF THE UTILITY MODEL

The problems that the manufacturing process is complex, the quality control is difficult, the structure cost is high, the equipment investment is high, the requirements on production suppliers are high, and the supply cost is increased are solved. The utility model discloses a following technical scheme is in order to solve above-mentioned problem:

the application provides a single tube IGBT driver that connects in parallel, this single tube IGBT driver that connects in parallel includes: the IGBT heat sink comprises an IGBT chip assembly, a capacitor assembly, a driving plate assembly and a heat sink, wherein the capacitor assembly and the driving plate assembly are fixedly connected through a laminated busbar, and the IGBT chip assembly is arranged on two sides of the heat sink; the laminated busbar is provided with jacks and pins, electrodes of capacitors in the capacitor assembly are correspondingly assembled and connected with the jacks in the laminated busbar, and the pins on the laminated busbar are inserted into corresponding jacks on the driving plate assembly; each IGBT single tube chip in the IGBT chip assembly is connected to the radiating surfaces on two sides of the radiator in a clamping manner through clamping springs, and each clamping spring is used for clamping two IGBT single tube chips to two side surfaces of the radiator respectively.

In some examples, the single-tube IGBT parallel driver further includes a positive terminal, a negative terminal, and a phase copper bar, wherein the positive terminal and the negative terminal are disposed on the laminated bus bar and respectively connected to the insertion holes and the insertion pins of the laminated bus bar; the phase copper bar is arranged in the driving plate assembly, the phase copper bar is connected with the driving plate assembly through pins of the phase copper bar, and the pins of the phase copper bar are correspondingly connected with each IGBT single tube chip in the IGBT chip assembly.

In some examples, the phase copper bars are arranged in three phases and connected with traction equipment through external leads, and the positive electrode end and the negative electrode end are connected with an external direct current power supply.

In some examples, an insulating pad for insulating and isolating is arranged between the three-phase copper bar and the driving plate, the three-phase copper bar is assembled between double rows of jacks of the driving plate, and a copper column connected with the traction equipment is arranged at the center of each three-phase copper bar.

In some examples, the capacitor assembly includes a first plastic housing with an unsealed bottom, a through hole is formed in a top of the first plastic housing, and an electrode of each capacitor in the capacitor assembly is inserted into a corresponding insertion hole of the laminated busbar through each through hole.

In some examples, the single-tube IGBT parallel driver further includes a plastic base, the plastic base divides the base into a first base and a second base by a spacer, a groove is formed at the bottom of the first base, and each capacitor in the capacitor assembly is correspondingly disposed in each groove; and the capacitor assembly is packaged and fixed in a space between the first plastic shell and the first base.

In some examples, a grid is disposed on the bottom of the second base, and the IGBT chip assembly is disposed on the bottom of the second base.

In some examples, the IGBT chip assembly includes a ceramic sheet disposed between a back surface of each IGBT chip of the IGBT chip assembly and a heat dissipation surface of the heat sink.

In some examples, the single-tube IGBT parallel driver further includes a thermal pad disposed between the driving board and the insulating pad, for conducting heat generated by the three-phase copper bar to the heat sink.

According to the single-tube IGBT parallel driver, the pins of the IGBT single-tube chip are electrically connected with the driving control board and the copper bar through the jacks or through holes preset in the driving board assembly and the jacks on the copper bar, then the pins are connected through the pre-placed bonding pads, and finally the pins of the IGBT single-tube chip are electrically connected with the driving control board and the copper bar through wave soldering; and the capacitors in the capacitor assembly are fixed through the plastic base, the electrodes of the capacitors are connected to the laminated busbar through the jacks of the plastic shell, the jacks reserved in the laminated busbar and the bonding pads, and the capacitors are welded to the laminated busbar through wave soldering and connected with an external direct-current power supply and the drive board assembly. Each IGBT single tube card in with IGBT chip subassembly is pressed the radiating surface of radiator through the jump ring, on the one hand with IGBT single tube chip fixed, on the other hand can be quick dispel the heat, the cooling to IGBT single tube chip. In the application, the pins of the IGBT single-tube chip are pre-fixed with the drive control board and the laminated busbar through jacks or through holes and the like, and the pins are simple to oppositely insert; then wave-soldering is carried out to realize electric connection, and the pins are not deformed after soldering; common wave soldering is used for welding, no welding equipment is required to be additionally arranged, and the cost is low; welding pads are preassembled at the welding positions of the pins of the IGBT single-tube chip and the pins of the phase copper bar, so that the welding surface is enlarged, and the current capacity of the single-tube IGBT parallel driver is increased.

Drawings

Fig. 1 is a schematic structural diagram of an exemplary single-tube IGBT parallel driver in an embodiment of the present application;

FIG. 2 is a schematic structural diagram of a capacitor device according to an embodiment of the present disclosure;

FIG. 3 is a schematic structural diagram of the capacitor module according to the embodiment of the present application after assembly;

FIG. 4 is a schematic diagram of the composition and assembly of an IGBT chip assembly according to an embodiment of the present application;

FIG. 5 is a schematic structural diagram of a plastic base according to an embodiment of the present application;

FIG. 6 is an assembly schematic of the drive plate assembly of the present application;

FIG. 7 is a schematic view of the assembly of the drive plate assembly and the capacitor assembly in an embodiment of the present application.

Detailed Description

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and are not intended to limit the scope of the present invention.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.

Fig. 1 shows a schematic structural diagram of an exemplary single-tube IGBT parallel driver to which embodiments of the present application can be applied.

As shown in fig. 1, the single-tube IGBT parallel driver proposed in the present embodiment includes: IGBT chip assembly 1, capacitor assembly 2, driver board assembly 3, and heat sink 4. The capacitor module 2 and the driving board module 3 are connected and fixed by a laminated busbar, the IGBT chip modules 1 are mounted on both sides of the heat sink 4, and the IGBT chip modules 1 and the IGBT chips are connected to the driving board module 3.

In this embodiment, referring to fig. 2 and fig. 3, fig. 2 is a schematic structural diagram of a capacitor assembly, and fig. 3 is a schematic structural diagram of the capacitor assembly after assembly. As shown in fig. 2, the capacitor assembly 2 includes a capacitor group 21 including a plurality of capacitors and a laminated bus bar 23, each capacitor in the capacitor group 21 has four needle-like electrodes, and each capacitor is connected to the laminated bus bar 23 through the needle-like electrodes. The laminated busbar 23 has a jack 231 and a pin 232, and the electrodes of the capacitors are correspondingly assembled and connected with the jacks 231. Each pin 232 of the laminated busbar 23 is inserted into a corresponding jack position of the driving board assembly 3. Each IGBT single-tube chip in the IGBT chip assembly 1 is clamped or pressed to the heat dissipation surfaces on both sides of the heat sink 4 by clamp springs, wherein each clamp spring clamps and presses two IGBT single-tube chips to both sides of the heat sink 4, respectively. And pins of each IGBT single-tube chip in the IGBT chip assembly 1 are connected with the jacks reserved in the driving plate assembly 3. The laminated busbar 23 mainly functions to collect current and is used as a bus by being connected with a direct current power supply. The pins of the IGBT single-tube chip are connected by welding the pins and the jacks together, wherein reserved bonding pads are arranged on the jacks.

The capacitor assembly 2 includes a first plastic housing 22 with an unsealed bottom, a pin through hole 221 is formed in the top of the first plastic housing 22, and an electrode of each capacitor in the capacitor assembly 2 passes through each pin through hole 221 and is inserted into the corresponding insertion hole 231 of the laminated busbar 23. In a specific implementation manner, the capacitors in the capacitor bank 21 are arranged in parallel in two rows, and a partition board is arranged inside the first plastic casing 22 to separate the capacitors in the two rows; meanwhile, two rows of spaces formed by the partition plate and the wall of the first plastic shell 22 are used for fixing each capacitor. The positions of the pin through holes 221 on the top of the first plastic housing 22 correspond to the positions of the electrodes of the capacitor arrays in the capacitor assembly.

Meanwhile, the laminated busbar 23 is provided with two connecting through holes 233, and the first plastic shell 22 is provided with two connected cylindrical holes 222. The connecting through hole 233 corresponds to the cylindrical hole 222. When the laminated busbar 23 and the first plastic housing 22 are assembled, the cylindrical hole 222 penetrates through the connecting through hole 233 to realize the assembly of the laminated busbar 23 and the first plastic housing 22, and the laminated busbar 23 and the first plastic housing 22 are fixed by a connecting piece passing through the cylindrical hole 222 and the connecting through hole 233. The connector may be a connector such as a bolt or screw, and the inner bore of the cylindrical bore 222 may be threaded. The first plastic housing 22 is used to support the entire module and to fix the components in the module. The capacitor assembly 21, the first plastic shell 22 and the laminated busbar 23 are assembled in the order shown in fig. 2, and the assembled capacitor assembly 2 is shown in fig. 3.

In the single-tube IGBT parallel driver in this embodiment, the capacitor group 21 is formed by 16 capacitors, and the PIN through hole 221 is a group hole formed by 2 rows and 8 columns, and is a hole into which a PIN can be inserted. Each group of holes of the pin through holes 221 is composed of 4 small holes, and the positions of the 4 small holes are consistent with the pin positions of a single capacitor, so that pins of capacitor electrodes can be conveniently inserted.

Referring to fig. 4, fig. 4 shows a schematic diagram of the composition and assembly of the IGBT chip assembly in this embodiment. As shown in fig. 4, the IGBT chip assembly 1 includes a plurality of IGBT single-tube chips 11 and a clamp spring 12. The IGBT single-tube chip 11 is clamped and pressed onto the heat dissipation surface 41 of the heat sink 4 using the clamp spring 12. Specifically, the bottom of the heat sink 4 is provided with a plurality of slots, the bottom of the snap spring 4 is embedded into the heat sink 4 through the slots, and two pressing plates of the snap spring 12 respectively press one IGBT single-tube chip 11 onto two heat dissipation surfaces 41 of the heat sink 4. The IGBT chip module 1 further includes a ceramic sheet 6, and the ceramic sheet 6 is disposed between the back surface of each IGBT single-tube chip 11 of the IGBT chip module 1 and the heat radiation surface 41 of the heat sink 4. Wherein, because the back of the IGBT single-tube chip 11 has high voltage, direct contact with the heat dissipation surface 41 may cause electrification of the heat dissipation surface 41 and damage of the IGBT single-tube chip, and the ceramic sheet 6 is used for isolation of the IGBT single-tube chip 11 and the heat sink 4.

In this embodiment, the single-tube IGBT parallel driver further includes a plastic base 5. Referring to fig. 5, fig. 5 is a schematic structural diagram of the plastic base in this embodiment, as shown in fig. 5, the plastic base 5 is provided with an integrally formed spacer, and the base is divided into a first base 51 and a second base 52 by the spacer. Wherein, the bottom of the first base 51 is provided with a groove, and the capacitor module 2 is packaged and fixed in the space between the first plastic shell 22 and the first base 51. Specifically, after being assembled with the first plastic housing 22, the capacitors in the capacitor assembly 2 are respectively disposed in the corresponding grooves of the first base 51. The capacitors in the capacitor assembly 2 are embedded in the grooves, and the capacitors can be fixed through the grooves to prevent the capacitors from moving.

The bottom of the second base 52 is provided with a grid, and the IGBT chip assembly 1 is placed on the bottom of the second base 52. The space formed by the grids of the second base 52 has a space for fixing a single IGBT single tube and a space for fixing a radiator, and the grids can be used for radiating heat.

In this embodiment, the single-tube IGBT parallel driver further includes a positive terminal, a negative terminal, and a phase copper bar 31. The positive electrode end and the negative electrode end are arranged on the laminated busbar 23 and are correspondingly connected with the jack 231 and the pin 232 of the laminated busbar 23 respectively through a circuit on a circuit board; and the positive electrode end and the negative electrode end are externally led out of a connector and connected with an external direct current power supply. Referring to fig. 6, fig. 6 is an assembly schematic diagram of the driving board in the driving board assembly of the present embodiment, as shown in fig. 6, the phase copper bar 31 is disposed in the driving board assembly 3, the phase copper bar 31 is connected to the driving board assembly 3 through pins 311 thereof, and the pins 311 of the phase copper bar 31 are correspondingly connected to pins of each IGBT single-tube chip in the IGBT chip assembly 1.

In this embodiment, the phase copper bar 31 is provided in three phases and connected to an external traction device through an external lead, and the positive terminal and the negative terminal are connected to an external dc power supply through an external lead. An insulating pad 32 for insulating and isolating is arranged between the phase copper bar 31 and the drive plate assembly 3 which are arranged in three phases, and through holes are arranged at the corresponding positions of the phase copper bar 31, the insulating pad 32 and the drive plate assembly 3 and are subjected to insulating treatment, for example, an insulating sleeve is additionally arranged in the through holes; and fixing the copper bars to the driving plate assembly by using the through holes in a screw connection, riveting or welding manner and the like. A plurality of symmetrical pins 311 are also arranged at two sides of each phase copper bar, and the three-phase copper bar 31 is electrically connected with the IGBT single tube chip and the driving circuit which are connected to the driving plate component 3 through the pins 311; the center of each phase copper bar 31 is provided with a copper column 312, and the three-phase copper bar 31 is connected with external traction equipment through the copper column 312 to supply power to the connected traction equipment.

And double-row jacks 30 are formed at the positions where the driving plate component 3 and the three-phase copper bar 31 are assembled. The pins of the IGBT single-tube chip in the IGBT chip assembly 1 and the pins 311 of the phase copper bar 31 are respectively inserted into the corresponding positions of the double-row jack 30, so that the IGBT single-tube chip in the IGBT chip assembly 1, the three-phase copper bar 31, and the drive board assembly 3 are electrically connected to each other.

In this embodiment, the single-tube IGBT parallel driver further includes a heat conduction pad, and the heat conduction pad is disposed between the driving board assembly 3 and the heat sink 4, and is configured to conduct heat generated by the three-phase copper bar of the driving board assembly 3 to the heat sink 4. Specifically, after the phase copper bar is assembled to the driving board assembly 3, the heat conducting pad is attached to the phase copper bar 31, and the other contact surface of the heat conducting pad is attached to the upper surface of the heat sink 4. Its purpose is to prevent to lead to the fact the influence for drive plate subassembly 3 because of looks copper bar 31 is overheated, so with the heat conduction pad to the heat conduction that looks copper bar 31 produced on the radiator, reduce looks copper bar 31 and drive plate subassembly 3's temperature.

In this embodiment, pins of each IGBT single tube 11 chip and pins of the phase copper bar 31 in the IGBT chip assembly 1 are connected to preset jacks of the driving board assembly 3, and then are soldered by a wave soldering process. The assembly formed by assembling the IGBT chip assembly 1 and the radiator 4 is firstly connected with the laminated busbar 23, pins of the IGBT single tube 11 chip are connected with the pins 232, then the pins 232 of the laminated busbar 23 are inserted into the jacks 310 preset in the drive board assembly 3, and the connection between each IGBT single tube 11 chip and the drive board assembly 3 is realized through a wave soldering process.

The assembly process of the IGBT chip assembly 1 comprises the steps of firstly pasting a heat conducting pad on the radiator 4, then assembling the radiator 4 and the assembled capacitor assembly 2 together through a tool, then placing the ceramic plates coated with heat conducting silicone grease on two sides of the radiator 4 by using the tool, then assembling the IGBT single tube 11 on the ceramic plates, and finally clamping the clamp spring.

Referring to fig. 7, fig. 7 is a schematic view illustrating the assembly of the driving board assembly and the capacitor assembly, and as shown in fig. 7, the pins 232 in the laminated busbar 23 are inserted into the corresponding sockets 30 in the driving board assembly 3, so as to complete the assembly of the driving board assembly and the capacitor assembly, and then assembled into the driving module. Before the drive plate assembly and the capacitor assembly are assembled, a heat conducting pad is arranged between the drive plate assembly and the capacitor assembly so as to conduct heat generated by the phase copper bar.

The assembled driving module and the tool enter a wave crest soldering furnace together, all holes penetrating copper bar pins or IGBT single tube chip pins of the driving board assembly are provided with bonding pads, wave crest soldering is performed on the bonding pads, the auxiliary tool is taken down after soldering is completed, and all assembling work of the driving module is completed. And finally, the plastic base and the driving module are assembled into a whole to form a single-tube IGBT parallel driver.

The application has the following beneficial effects:

the capacitor assembly is embedded in the space between the plastic shell and the plastic base, so that the positions of the capacitors in the capacitor assembly are fixed, and the capacitors can be prevented from moving.

The laminated busbar is fixedly connected to the plastic shell through a preset mounting hole; the pin through holes of the plastic shell correspond to the jack positions of the laminated busbar one by one; the electrodes of all capacitors of the capacitor assembly are inserted into the jacks of the laminated busbar through the pin through holes of the plastic shell, the bonding pads are arranged at the jacks, after wave-soldering treatment, the capacitors are connected with the laminated busbar, welding and operation are simple, and deformation is not easy.

The IGBT chip assembly is clamped and pressed on the radiator through the clamp spring, the IGBT single tube chip is fixed, contact between the IGBT single tube chip and the radiating surface is increased, and radiating of the IGBT single tube chip is facilitated; the pin of IGBT single tube chip is through female pin of arranging of stromatolite and the jack connection of drive plate subassembly, at female pin of arranging of stromatolite and the pin welding department of IGBT single tube chip to and female pin of arranging of stromatolite and the jack welding department of drive plate subassembly all are equipped with the pad, cross wave-soldering, make the pin of IGBT single tube chip switch on with the looks copper bar and drive circuit is connected, and the pin does not take place deformation at this in-process, guarantees welding quality.

The ceramic wafer arranged between the radiating surface of the radiator and the IGBT single-tube chip plays a role in isolation, and prevents the IGBT single-tube chip from being burnt to cause interference.

The heat conducting pad arranged between the phase copper bar and the driving plate component can conduct heat generated by the phase copper bar to the radiator in time, so that the radiating efficiency is improved, and the normal work of the driving plate component is guaranteed.

Therefore, the single-tube IGBT parallel driver in the application is simple to manufacture, the pins of the chip are inserted into the welding positions in advance, the pins are not deformed in the whole welding process, quality control is easy, common wave soldering is adopted in welding, cost is low, and new equipment is not needed to be input.

So far, the technical solution of the present invention has been described with reference to the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, a person skilled in the art can make equivalent changes or substitutions to the related technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A single-tube IGBT parallel driver is characterized by comprising: the IGBT module comprises an IGBT chip component, a capacitor component, a driving plate component and a radiator, wherein the capacitor component and the driving plate component are fixedly connected through a laminated busbar, and the IGBT chip component is arranged on two sides of the radiator; wherein the content of the first and second substances,

the laminated busbar is provided with jacks and contact pins, electrodes of capacitors in the capacitor assembly are correspondingly assembled and connected with the jacks in the laminated busbar, and the contact pins on the laminated busbar are inserted into corresponding jack positions on the driving plate assembly;

each IGBT single tube chip in the IGBT chip assembly is clamped to the radiating surfaces on two sides of the radiator through clamp springs, wherein each clamp spring clamps two IGBT single tube chips to two side surfaces of the radiator respectively.

2. The single-tube IGBT parallel driver of claim 1, further comprising a positive terminal, a negative terminal, and a phase copper bar, wherein,

the positive electrode end and the negative electrode end are arranged on the laminated busbar and are respectively and correspondingly connected with the jack and the contact pin of the laminated busbar;

the phase copper bar is arranged in the driving plate assembly, the phase copper bar is connected with the driving plate assembly through pins of the phase copper bar, and the pins of the phase copper bar are correspondingly connected with each IGBT single tube chip in the IGBT chip assembly.

3. The single-tube IGBT parallel driver as claimed in claim 2, wherein the phase copper bar is arranged in three phases and connected to a traction device through an external wire, and the positive terminal and the negative terminal are connected to an external DC power supply.

4. The single-tube IGBT parallel driver as claimed in claim 3, wherein an insulating pad for insulation is disposed between the phase copper bar and the driving board, the phase copper bar is assembled between the two rows of jacks of the driving board, and a copper column connected with the traction device is disposed at the center of each phase copper bar.

5. The single-tube IGBT parallel driver as claimed in claim 4, wherein the capacitor assembly comprises a first plastic housing with an unsealed bottom, a through hole is formed in the top of the first plastic housing, and an electrode of each capacitor in the capacitor assembly is inserted into the corresponding jack of the laminated busbar through each through hole.

6. The single-tube IGBT parallel driver as claimed in claim 5, further comprising a plastic base, wherein the plastic base divides the base into a first base and a second base by a spacer, the bottom of the first base is provided with a groove, and each capacitor in the capacitor assembly is respectively and correspondingly disposed in each groove; and the capacitor assembly is packaged and fixed in the space between the first plastic shell and the first base.

7. The single-tube IGBT parallel driver of claim 6, wherein the bottom of the second base is provided with a grid, and the IGBT chip assembly is placed on the bottom of the second base.

8. The single-tube IGBT parallel driver according to claim 7, wherein the IGBT chip assemblies include a ceramic sheet disposed between a back surface of each of the IGBT single-tube chips of the IGBT chip assemblies and a heat radiation surface of the heat sink.

9. The single-tube IGBT parallel driver according to claim 8, further comprising a thermal pad disposed between the driving board and the insulating pad for conducting heat generated by the phase copper bar to the heat sink.