KR20190072912A - Inverter structure for vehicle - Google Patents

Abstract

The present invention provides an inverter structure for a vehicle which increases durability of a power module and prevents damage. The inverter structure for a vehicle comprises: a capacitor receiving direct current (DC) current from a high voltage battery; a power module having an input P terminal, an input N terminal, and an alternating current (AC) output terminal, and elastically connected with the capacitor to convert and output the DC current transferred from the capacitor into AC current; and a plurality of DC bus bars located between the capacitor and the power module and individually connected to the input P terminal and the input N terminal of the power module to allow the current to flow in different directions from each other, thereby reducing stray inductance.

Description

[0001] INVERTER STRUCTURE FOR VEHICLE [0002]

The present invention relates to an inverter structure that receives a DC current from a high voltage battery and smooths it and transfers the smoothed capacitor to a capacitor, and a capacitor converts a DC current into an AC current of three phases. More particularly, To an inverter structure of a vehicle capable of reducing a stray inductance generated by electromagnetic induction between a module and a capacitor.

Eco-friendly vehicles, such as hybrid vehicles and electric vehicles, use an electric motor as a driving source. Generally, a high-voltage battery is used as an energy source for driving an electric motor. LDC (Low DC-DC Converter) is used. Here, the inverter is provided so as to convert the DC power of the high-voltage battery into the three-phase AC power between the electric motor and the high-voltage battery and supply the DC power to the drive motor side.

Conventional electric automobiles are predominantly driven by relatively low output models of about 100 kW for short-distance and city driving. That is, since a high output is not required, one motor, which is a power source of the electric vehicle, is normally used for the front wheel, and accordingly, the inverter that supplies current to the motor is also designed to cope with the output of a relatively narrow area.

However, as a variety of electric vehicles such as a sports car type and an SUV type have recently been developed, the output specifications required for electric vehicles have been diversified. It is not possible to cope with the increased output specifications due to the size and weight limit of the drive motor only with one motor, and an electric vehicle model in which a plurality of drive motors are arranged in the front and rear wheels is also being developed. Therefore, the specification of the inverter that supplies current to the motor is also diversified. For example, when a motor of 200 kW is disposed on the front wheel and a motor of 300 kW is disposed on the rear wheel, there arises a problem that two motors can not be simultaneously accommodated by the same inverter.

On the other hand, an inverter configured in a plane is generally arranged such that a power module, a capacitor, and an LDC are disposed on the bottom surface of the housing, and a control board is disposed on the top of the inverter. Below the power module and LDC, which have high heat generation, a cooling channel through which cooling water flows is formed to prevent performance degradation due to overheating, and to prevent the device from being damaged.

Typical inverters use a single power module to convert the current. To increase the output, use a high power module or add the number of power modules. It is difficult to realize a high output which is higher than a certain level due to the characteristics of the switching device constituting the power module. Therefore, most inverters connect a plurality of power modules in parallel in order to cope with high output specifications. However, when the number of power modules is increased, a plurality of power modules are connected to one capacitor, so that a distance between the power module and the capacitor connecting portion as well as a distance difference between each power module and the capacitor becomes a problem. When the distance between the power module and the capacitor connection increases, the stray inductance also increases. As a result, there is a difference in distance between each power module and the capacitor, and a stray inductance unbalance occurs between the power modules, There is a problem that the risk increases.

It should be understood that the foregoing description of the background art is merely for the purpose of promoting an understanding of the background of the present invention and is not to be construed as an admission that the prior art is known to those skilled in the art.

KR10-2012-0017545 (A)

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve such a problem, and it is an object of the present invention to provide a power module for reducing the stray inductance generated at each power module and capacitor connection part, And the inverter structure of FIG.

According to an aspect of the present invention, there is provided an inverter structure of a vehicle, including: a capacitor receiving a DC current from a high voltage battery; A power module having an input P stage, an input N stage, and an AC output stage, and converting the DC current received from the capacitor into an AC current of three phases and outputting the AC current; And a plurality of DC bus bars positioned between the capacitors and the power module and coupled to the input P-stage and the input N-stage of the power module, respectively, to allow current to flow in different directions, thereby reducing the stray inductance .

The capacitor includes a plurality of output terminals for receiving a DC current from the high voltage battery and a smoothing current on the power module side of the capacitor. The input P stage, the input N stage, and the AC output stage of the power module, Each of which is a conductor, may be provided.

A DC bus bar having a coupling hole formed between an input P-stage and an input N-stage of the power module, and an output terminal of the capacitor, respectively, and coupling members extending upwardly are provided at output ends of the capacitor, And a through hole is formed in the AC output terminal, respectively, so that the coupling member is coupled to the coupling hole and the through hole, respectively, so that the capacitor and the power module can be electrically connected.

Between the capacitor and the power module, a terminal of the capacitor, a terminal of the power module, and a terminal block where the coupling member is disposed are provided, and the capacitor and the power module can be coupled and electrically connected to each other in the terminal block.

The terminal block is provided with a terminal block case having a nonconducting potential to connect the input terminal P, the input N terminal and the AC output terminal of the power module to the output terminal of the capacitor, and the terminal block case can be divided into one- have.

The DC bus bar to be connected to the input P-stage of the power module and the DC bus bar to be connected to the input N-stage of the power module are formed to surround the terminal block case at the position where the input P- Can be installed.

The terminal block case has a terminal hole through which the fastening member passes, a through hole is formed in a terminal of an input terminal P, an input terminal N, and an AC output terminal of the power module, a fastening hole is formed in a DC bus bar, The through hole and the fastening hole are arranged to communicate with each other so that the fastening member can be simultaneously penetrated into the terminal hole, the through hole and the fastening hole.

The terminal hole of the terminal block case where the AC output terminal of the power module is located is provided with an insert ring as a conductor, and the fastening member can be coupled to the insert ring.

The DC bus bar includes a plate-shaped upper surface, a side surface extending from one end edge of the upper surface by being bent downward, and a lower surface extending from the edge of the one end surface of the side surface in the same direction as the upper surface. And a fastening hole for fastening the fastening member to the upper surface and the lower surface, respectively.

The DC bus bar is disposed so that the sides of the DC bus bar connected to the input P stage and the side surface of the DC bus bar connected to the input N stage are opposed to each other when the input P stage and the input N stage are coupled, .

A plurality of power module units are stacked in a vertical direction. A plurality of power module units are stacked in the vertical direction. A cooler having a surface contact with the power module unit is alternately arranged on the upper and lower sides of the power module unit. And the cooler may be positioned at the outermost side of the upper side and the lower side.

According to the inverter structure of the vehicle constructed as described above, there is an advantage that the reliability and durability of the power module can be improved and the risk of burning of the power module can be reduced. Therefore, since a higher current can be used in the power module, there is an effect that the output of the power conversion device can be improved compared to the conventional one.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a structure of an inverter of a vehicle according to an embodiment of the present invention; Fig.
Fig. 2 is an exploded perspective view of Fig. 1; Fig.
3 is a view showing a terminal block.
FIG. 4 is an exploded perspective view of FIG. 3; FIG.
5 is a sectional view of Fig. 3; Fig.
Figure 6 is a simplified version of the current flow of Figure 3;
7 is a graph showing an analysis of the present invention and conventional stray inductance.

Hereinafter, an inverter structure of a vehicle according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a view showing an inverter structure of a vehicle according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of FIG. 3 is an exploded perspective view of FIG. 3, FIG. 5 is a cross-sectional view of FIG. 3, and FIG. 6 is a simplified view of the current flow of FIG. 7 is a graph showing an analysis of the present invention and conventional stray inductance.

1 and 2, an inverter structure of a vehicle according to a preferred embodiment of the present invention includes: a capacitor 100 receiving a DC current from a high voltage battery (not shown); An input P stage 310, an input N stage 330 and an AC output stage 350 and is connected to the capacitor 100 to convert the DC current received from the capacitor 100 into an AC current of three phases, A power module (300); And between the capacitor 100 and the power module 300 and coupled to the input P stage 310 and the input N stage 330 of the power module 300 to allow current to flow in different directions, And a plurality of DC bus bars 530 for reducing stray inductance.

A plurality of input terminals 110 and a plurality of output terminals 130 are provided in the capacitor 100. The capacitor 100 receives a DC current from a high-voltage battery through an input terminal 110 and smoothes it, and outputs a smoothed current to the power module 300 through an output terminal 130.

The power module 300 includes an input P stage 310, an input N stage 330 and an AC output stage 350 and is electrically connected to the capacitor 100. Thus, the DC current received from the capacitor 100 is converted into a three-phase AC current, which is a U, W, and W phase, and is output to a driving motor (not shown). The power module 300 is in the form of a plate, and a plurality of power modules 300 are provided to form three rows of power module units 900, and a plurality of power module units 900 are stacked in the vertical direction. In the present specification, the power module 300 is arranged horizontally in three columns and the power module unit 900 is horizontally arranged in three rows, and is configured to have 3X3, for example. Accordingly, the power module unit 900 has the terminals of the input P stage 310, the input N stage 330, and the AC output stage 350 at the same position in the vertical direction. Cooling units 700 are provided on the upper and lower sides of the power module unit 900 so as to be alternated with the power module unit 900. Cooling units 700 are disposed on the upper and lower outermost sides of the power module unit 900, Is positioned to cool the power module 300.

As shown in FIGS. 3 to 6, a terminal block 500 is provided between the capacitor 100 and the power module 300. The terminal block 500 is provided with a terminal block case 590 having a nonconductive shape formed of a material such as plastic and the components are fixed to the terminal block case 590 to isolate unnecessary current flow between the components. The output terminal 130 and the coupling member 550 of the capacitor 100 are disposed in the terminal block 500 and the terminals 310, 330 and 350 of the power module 300 are disposed in the terminal block case 590. In particular, the terminal block case 590 further includes a DC bus bar 530 and an insert ring 570. Therefore, the capacitor 100 and the power module 300 are connected and electrically connected to each other within the terminal block 500, particularly, the terminal block case 590. The configuration of the terminal block 500 will be described in more detail.

First, the terminal block 500 is provided in the capacitor 100, and the output terminal 130 of the capacitor 100 and the coupling member 550 are provided. The terminal block 500 further includes a terminal block case 590. The terminal block case 590 is connected to the input terminal P 310 of the power module 300 and the input N terminal 330 and the AC output terminal 350 of the capacitor 100 The zones 510 are divided into one to one correspondence with the output ends 130 of the respective zones. Zone 510 would preferably be divided by the same area. Terminal holes 511 are vertically formed in the top and bottom surfaces of the terminal block case 590.

The coupling member 550 is connected to the input P stage 310, the input N stage 330 and the AC output stage 350 of the power module 300 and the output stage 130 of the capacitor 100, Respectively. Although the fastening member 550 is a bar-shaped stud and will be described by way of example, the fastening member 550 may be a bolt or the like. The fastening member 550 is passed through the terminal hole 511 and finally is fastened by a nut 551. [

A DC bus bar 530 is provided at a point where the output stage 130 of the capacitor 100 meets the input P stage 310 and the input N stage 330 of the power module 300. The DC bus bar 530 is provided in a terminal block case 590 located between the capacitor 100 and the power module 300. The DC bus bar 530 is connected to the input P stage 310 and the input N stage (330) so that currents flow in different directions when a current is applied, so that the magnetic fields formed by the electromagnetic induction are offset from each other, thereby reducing the stray inductance. More specifically, the DC bus bar 530 includes a plate-like upper surface 531, a side surface 533 extending downwardly from the edge of one end of the upper surface 531 and extending from the edge at one end of the side surface 533 And a lower surface 535 which is bent and extended in the same direction as the upper surface 531. The upper surface 531 and the lower surface 535 are each formed with a fastening hole 537 to be fastened to the fastening member 550 . In other words, the DC bus bar 530 is a "C"

The DC bus bar 530 is connected to the input P stage 310 and the input N stage 330. The DC bus bar 530 is connected to the input P stage 310 and the side 533 of the DC bus bar 530, The side faces 533 of the DC bus bar 530 connected to the bus bars 330 are disposed to face each other so that the side faces 533 are disposed closest to each other and a current flows in opposite directions when energized, So that the stray inductance is reduced. The DC bus bar 530 connected to the input P stage 310 and the DC bus bar 530 connected to the input N stage 330 are connected to each other with respect to the partition wall 591 of the terminal block case 590 zone 510 It is installed symmetrically. The DC bus bar 530 fastened to the input P end 310 of the power module 300 and the DC bus bar 530 fastened to the input N end 330 of the power module 300 are connected to the power module 300 The input terminal P 310 and the input N terminal 330 of the power module 300 are disposed so as to surround the terminal block case 590 from the outside so that the side surfaces 533 of the DC bus bar 530 Respectively. Particularly, the DC bus bar 530 can be manufactured by using one mold and then assembled so as to be opposite to each other, so that the production cost can be reduced and the production efficiency can be increased.

The terminals of the input P stage 310, the input N stage 330 and the AC output stage 350 of the power module 300 are plate-shaped and the through holes 370 are formed in the terminals 310, 330 and 350, As shown in Fig. The input P stage 310 and the input N stage 330 of the power module 300 are electrically connected between the power module units 900 stacked by the DC bus bar 530 in the terminal block case 590, An insert ring 570 as a conductor is provided in the terminal hole 511 of the terminal block case 590 to electrically connect the stacked power module units 900 to each other. The insert ring 570 is preferably press-fitted into the terminal hole 511 of the terminal block case 590 and assembled.

Therefore, a plurality of terminal block cases 590 are stacked between the capacitor 100 and the power module 300. The output terminal 130 of the capacitor 100 is mounted on the terminal block 500 and the coupling member 550 is mounted on the output terminal 130 in the vertical direction, . The DC bus bar 530 or the insert ring 570 is assembled to the terminal block case 590 and then the terminals 310, 330 and 350 of the capacitor 100 are stacked. Particularly, the terminal hole 511 of the terminal block case 590, the fastening hole 537 of the DC bus bar 530 and the through hole 370 of the terminal of the power module 300 are arranged to communicate with each other, The capacitor 100 and the power module 300 are electrically connected to each other through the terminal hole 511, the through hole 370 and the connection hole 537 at the same time. At the uppermost end of the fastening member 550, a nut 551 is fastened to secure the fastening.

In the present invention, the current flow formed by contacting the AC output terminal 350 of the power module 300 and the insert ring 570 of the terminal block case 590 is the same as a general current flow. The current formed by the input P stage 310 of the power module 300, the DC bus bar 530 and the input N stage 330 and the bus bar are in contact with each other and the DC bus bar 530 is formed symmetrically, So that they flow in different directions and flow at a point close to each other.

The stray inductance is typically a resistance component formed by electromagnetic induction that occurs when the current changes. However, as in the present invention, when currents are caused to flow in mutually opposite directions, a reverse magnetic field is formed, and in particular, the nearby magnetic fields cancel each other. A magnetic field is generated at the currents flowing in opposite directions in the DC bus bar 530 connected to the input P stage 310 of the terminal block 500 and the DC bus bar 530 connected to the input N stage 330, And the stray inductance is reduced as a result.

This can be confirmed in detail in Fig. 7 is a graph showing an analysis of the present invention and conventional stray inductance.

Generally, when a plurality of power modules 300 are connected to the capacitor 100 for the purpose of increasing the output of the power conversion device, the physical connection distance becomes long, the connection distance between the power modules 300 becomes different, and the stray inductance increases, There is an imbalance between the inductances. In the present specification, a "? "Shaped DC bus bar 530 symmetrical to the terminal block case 590 connected between the power modules 300 is inserted to reduce the stray inductance by using magnetic field cancellation of currents flowing in mutually opposite directions do.

Analysis of the stray inductance of the inverter structure according to the conventional structure and the embodiment of the present invention shows that the stray inductance between the first layer power module 300 and the second layer power module 300 is reduced by 45% from 2.88 nH to 1.59 nH, The stray inductance between the first layer power module 300 and the third layer power module 300 is reduced by 60% from 6.89 nH to 2.74 nH. In addition, the difference in the stray inductance between the respective layers of the power module 100 is 4.01 nH, which is the difference between the conventional structure of 2.88 nH and 6.89 nH, but is reduced to about 1.55 nH by 71% in the present invention.

The stray inductance causes a peak voltage when the current of the power module 300 is suddenly changed during the switching operation of the power module 300, thereby causing the power module 300 to be destroyed. Therefore, according to the inverter structure of the vehicle of the present invention as described above, the reliability and durability of the power module 300 can be improved, and the risk of burning of the power module 300 can be reduced. Therefore, since a higher current can be used in the power module 300, there is an effect that the output of the power conversion device can be improved compared with the conventional one.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the following claims It will be apparent to those of ordinary skill in the art.

100: capacitor 110: input terminal
130: Output stage 300: Power module
310: input P stage 330: input N stage
350: AC output terminal 370: through hole
500: Terminal block 510: Zone
511: terminal hole 530: DC bus bar
531: upper surface 533: side surface
535: lower surface 537: fastening hole
550: fastening member 570: insert ring
590: Terminal block case 591:
700: Cooler 900: Power module unit

Claims (11)

A capacitor receiving a DC current from the high voltage battery;
A power module having an input P stage, an input N stage, and an AC output stage, and converting the DC current received from the capacitor into an AC current of three phases and outputting the AC current; And
And a plurality of DC bus bars located between the capacitors and the power module and coupled to the input P-stage and the input N-stage of the power module, respectively, so that the stray inductance is reduced by allowing current to flow in different directions. Inverter structure. The method according to claim 1,
The capacitor includes a plurality of output terminals for receiving a DC current from the high voltage battery and a smoothing current on the power module side of the capacitor. The input P stage, the input N stage, and the AC output stage of the power module, And a coupling member, which is a conductor, is provided at a point where each of the coupling members is located. The method according to claim 1,
A DC bus bar having a coupling hole formed between an input P-stage and an input N-stage of the power module, and an output terminal of the capacitor, respectively, and coupling members extending upwardly are provided at output ends of the capacitor, And the AC output terminal is formed with a through hole, respectively, so that the coupling member is coupled to the coupling hole and the through hole, respectively, so that the capacitor and the power module are electrically connected to each other. The method according to claim 1,
Wherein a terminal of the capacitor, a terminal of the power module, and a terminal block in which the coupling member is disposed are provided between the capacitor and the power module, and the capacitor and the power module are electrically connected to each other in the terminal block. The method of claim 4,
The terminal block is provided with a terminal block case having a nonconducting potential for connecting the input terminal P, the input N terminal, and the AC output terminal of the power module to the output terminal of the capacitor, and the terminal block case is divided into a one- Characterized in that the inverter structure of the vehicle. The method of claim 4,
The DC bus bar to be connected to the input P-stage of the power module and the DC bus bar to be connected to the input N-stage of the power module are formed to surround the terminal block case at the position where the input P- Wherein the inverter is mounted on the vehicle. The method of claim 4,
The terminal block case has a terminal hole through which the fastening member passes, a through hole is formed in a terminal of an input terminal P, an input terminal N, and an AC output terminal of the power module, a fastening hole is formed in a DC bus bar, Wherein the through hole and the fastening hole are arranged so as to communicate with each other so that the fastening member is simultaneously penetrated through the terminal hole, the through hole and the fastening hole. The method of claim 7,
Characterized in that the terminal hole of the terminal block case where the AC output terminal of the power module is located is provided with an insert ring as a conductor, and a fastening member is coupled to the insert ring. The method according to claim 1,
The DC bus bar includes a plate-shaped upper surface, a side surface extending from one end edge of the upper surface by being bent downward, and a lower surface extending from the edge of the one end surface of the side surface in the same direction as the upper surface. And a fastening hole to be fastened to the fastening member is formed on the upper surface and the lower surface, respectively. The method of claim 9,
The DC bus bar is disposed so that the sides of the DC bus bar connected to the input P stage and the side surface of the DC bus bar connected to the input N stage are opposed to each other when the input P stage and the input N stage are coupled, And wherein the inverter is installed in the vehicle. The method according to claim 1,
A plurality of power module units are stacked in a vertical direction. A plurality of power module units are stacked in the vertical direction. A cooler having a surface contact with the power module unit is alternately arranged on the upper and lower sides of the power module unit. And a cooler is disposed on the outermost side of the upper side and the lower side of the inverter.

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