KR102554923B1 - Inverter structure for vehicle - Google Patents

Abstract

a capacitor receiving DC current from the high voltage battery; a power module having an input P terminal, an input N terminal, and an AC output terminal, electrically connected to a capacitor, and converting DC current received from the capacitor into three-phase AC current for output; And a plurality of DC bus bars located between the capacitor and the power module, coupled to the input P terminal and the input N terminal of the power module, respectively, to allow current to flow in different directions, thereby reducing stray inductance. An inverter structure of a vehicle is introduced.

Description

Vehicle inverter structure {INVERTER STRUCTURE FOR VEHICLE}

The present invention relates to an inverter structure in which DC current is supplied from a high-voltage battery, smoothed, and then transferred to a capacitor, and the capacitor phase-converts the DC current into a three-phase AC current. An inverter structure of a vehicle capable of reducing stray inductance generated by electromagnetic induction between a module and a capacitor.

Eco-friendly vehicles that use an electric motor as a driving source, such as a hybrid vehicle or an electric vehicle, usually use a high-voltage battery as an energy source to drive the electric motor, and generate an inverter that provides power to the motor and a 12V power source for the vehicle as a power conversion part. LDC (Low DC-DC Converter) is used to do this. Here, the inverter is provided to convert the DC power of the high voltage battery into three-phase AC power between the electric motor and the high voltage battery and provide it to the driving motor side.

Conventional electric vehicles have been dominated by models with a relatively low output of about 100 kW, mainly for short-distance and city driving. That is, since high power was not required, one motor, which is a power source of an electric vehicle, was usually used for the front wheels, and accordingly, an inverter supplying current to the motor was also prepared to correspond to a relatively narrow range of output.

However, with the recent development of various electric vehicles such as sports car type and SUV type, the output specifications required for electric vehicles are diversifying. Due to the size and weight limitations of the drive motor, it is impossible to cope with the increased output specifications with only one motor, and an electric vehicle model in which multiple drive motors are placed on the front and rear wheels is also being developed. Therefore, the specifications of inverters that supply current to motors are diversifying. For example, if motors of 200 kW for the front wheels and 300 kW for the rear wheels are disposed, a problem arises in that the same inverter cannot simultaneously handle the two motors.

On the other hand, in an inverter configured on a flat surface, a power module, a capacitor, and an LDC are generally disposed on the bottom surface of a housing, and a control board is located on the top thereof. Cooling oil through which coolant flows is formed under the power module and LDC, which generate excessive heat, to prevent performance degradation or element burnout due to overheating.

A general inverter uses one power module to convert current, and in order to increase the output, a high-output power module must be used or the number of power modules must be added. Due to the characteristics of the switch element constituting the power module, it is difficult to implement a high output higher than a certain level. Accordingly, most inverters connect a plurality of power modules in parallel to meet the high output specifications. However, when the number of power modules increases, as a plurality of power modules are connected to one capacitor, not only the distance between the power module and the capacitor connection part increases, but also the distance difference between each power module and the capacitor becomes a problem. As the distance between the power module and the capacitor connection increases, the stray inductance also increases, and as a distance difference between each power module and the capacitor occurs, an imbalance in stray inductance occurs between the power modules, and a load is applied to a specific power module, causing the power module to burn out. A problem arises that increases the risk.

The matters described as the background art above are only for improving understanding of the background of the present invention, and should not be taken as an admission that they correspond to prior art already known to those skilled in the art.

KR10-2012-0017545 (A)

The present invention has been proposed to solve this problem, and even if a plurality of power modules are connected to one capacitor, stray inductance generated at each power module and capacitor connection is reduced to increase the durability of the power module and prevent burnout. Its purpose is to provide an inverter structure of

In order to achieve the above object, an inverter structure of a vehicle according to the present invention includes a capacitor receiving DC current from a high voltage battery; A power module having an input P terminal, an input N terminal, and an AC output terminal, electrically connected to a capacitor, and converting DC current received from the capacitor into three-phase AC current for output; and a plurality of DC bus bars located between the capacitor and the power module and coupled to the input P terminal and the input N terminal of the power module, respectively, to allow current to flow in different directions, thereby reducing stray inductance. .

The capacitor has an input terminal for receiving DC current from the high voltage battery, and a plurality of output terminals for outputting smoothed current are provided on the power module side of the capacitor. A fastening member that is a conductor may be provided at each meeting point.

A DC bus bar having a fastening hole is provided between the input P and N terminals of the power module and the output terminal of the capacitor, respectively, and a fastening member extending upward is provided at the output terminal of the capacitor, respectively, and the input P and input N terminals of the power module Through-holes are formed in the terminal and the AC output terminal, respectively, and the fastening member is penetrated through and coupled to the fastening 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 block on which a terminal of the capacitor, a terminal of the power module, and a fastening member are disposed is provided, and the capacitor and the power module are fastened to each other in the terminal block to be electrically connected.

The terminal block is provided with a non-conductive terminal block case that allows the terminals of the input P terminal, input N terminal, and AC output terminal of the power module to be coupled to the output terminal of the capacitor, respectively, and the terminal block case can be divided into zones so that they correspond to terminals one-to-one. there is.

The DC bus bar connected to the input P terminal of the power module and the DC bus bar connected to the input N terminal of the power module are shaped to surround the terminal block case at the point where the input P terminal of the power module and the input N terminal of the power module are located from the outside. can be installed

Terminal holes are formed in the terminal block case for fastening members to pass through, through-holes are formed in the terminals of the input P terminal, input N terminal, and AC output terminal of the power module, and fastening holes are formed in the DC bus bar, terminal holes, The through hole and the fastening hole are arranged to be in communication with each other so that the fastening member can be through-coupled to the terminal hole, the through hole and the fastening hole at the same time.

An insert ring, which is a conductor, is provided in the terminal hole of the terminal block case where the AC output end of the power module is located, and a fastening member may be penetrated through the insert ring.

The DC bus bar includes a plate-shaped upper surface, a side surface bent downward from one end edge of the upper surface and extended, and a lower surface bent and extended in the same direction as the upper surface again at one end edge of the side surface. Fastening holes fastened to the fastening member may be respectively formed on the upper and lower surfaces.

When the DC bus bar is connected to the input P terminal and the input N terminal, the side of the DC bus bar connected to the input P terminal and the side of the DC bus bar connected to the input N terminal face each other so that current flows in opposite directions when energized. can be installed as well.

The power module is in the form of a plate, and a plurality of power module units are provided to form three rows of power module units. Doedoe, the cooler may be located at the outermost of the upper and lower sides.

According to the inverter structure of the vehicle having the structure as described above, there is an advantage in that the risk of burnout of the power module can be reduced by improving the reliability and durability of the power module. Therefore, since a higher current can be used in the power module, there is an effect of improving the output of the power converter compared to the prior art.

1 is a diagram showing an inverter structure of a vehicle according to an embodiment of the present invention.
Figure 2 is an exploded perspective view of Figure 1;
3 is a diagram showing a terminal block;
Figure 4 is an exploded perspective view of Figure 3;
Figure 5 is a cross-sectional view of Figure 3;
Figure 6 is a simplified view of the current flow of Figure 3;
7 is a graph analyzing the stray inductance of the present invention and the related art.

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

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. 1 . 3 is a view showing the terminal block 500, FIG. 4 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 current flow in FIG. 7 is a graph in which the present invention and the conventional stray inductance are analyzed.

As shown in FIGS. 1 and 2 , the inverter structure of a vehicle according to a preferred embodiment of the present invention includes a capacitor 100 receiving DC current from a high voltage battery (not shown); An input P terminal 310, an input N terminal 330, and an AC output terminal 350 are provided, and are electrically connected to the capacitor 100 to convert the DC current received from the capacitor 100 into a three-phase AC current for output. The power module 300 to; And it is located between the capacitor 100 and the power module 300, and is coupled to the input P terminal 310 and the input N terminal 330 of the power module 300, respectively, so that current flows in different directions, It includes; a plurality of DC bus bars 530 to reduce 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 DC current from the high voltage battery through the input terminal 110, smooths it, and then outputs the smoothed current to the power module 300 through the output terminal 130.

The power module 300 includes an input P terminal 310, an input N terminal 330, and an AC output terminal 350, and is electrically connected to the capacitor 100. Accordingly, the DC current received from the capacitor 100 is converted into a three-phase AC current of U, W, and W phases and output to a driving motor (not shown). The power module 300 has a plate shape, and is provided in plurality to form three rows of power module units 900, and the plurality of power module units 900 are stacked vertically. In the present specification, the power module 300 is provided in three rows horizontally and the power module units 900 are provided in three rows horizontally to illustrate and describe a 3X3 configuration as an example, but this configuration can be changed as much as desired. Therefore, in the power module unit 900, terminals of the input P terminal 310, the input N terminal 330 and the AC output terminal 350 are located at the same position in the vertical direction. In addition, on the upper and lower sides of the power module unit 900, coolers 700 in surface contact with the power module unit 900 are alternately disposed with the power module unit 900, and coolers 700 are placed 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 non-conductive terminal block case 590 formed of a material such as plastic, and each component is fixed to the terminal block case 590 to insulate unnecessary flow of current between each component. The output terminal 130 of the capacitor 100 and the fastening member 550 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 electrically connected by being fastened to each other within the terminal block 500, in particular, the terminal block case 590. Let's take a look at each component provided in the terminal block 500 in more detail.

First, the terminal block 500 is provided in the capacitor 100, and the output end 130 of the capacitor 100 and the fastening member 550 are provided. The terminal block 500 further includes a terminal block case 590, in which the input P terminal 310, the input N terminal 330 and the AC output terminal 350 of the power module 300 are connected to the capacitor 100. The zone 510 is divided so that it is fastened in a one-to-one correspondence with the output terminal 130 of ). Zones 510 may preferably be divided into equal areas. Terminal holes 511 are formed through the upper and lower surfaces of the terminal block case 590 in the vertical direction.

The fastening member 550 is a conductor, and is located at a point where the input P terminal 310, the input N terminal 330, and the AC output terminal 350 of the power module 300 and the output terminal 130 of the capacitor 100 respectively meet. are provided The fastening member 550 is shown as a bar-shaped stud and described as an example, but the fastening member 550 may be a bolt or the like. After passing through the terminal hole 511, the fastening member 550 is finally fastened by the nut 551.

A DC bus bar 530 is provided at a point where the output terminal 130 of the capacitor 100 and the input P terminal 310 and the input N terminal 330 of the power module 300 meet. The DC bus bar 530 is more specifically provided in the terminal block case 590 located between the capacitor 100 and the power module 300, and the input P stage 310 and the input N stage of the power module 300 330, so that current flows in different directions when current is applied, so that magnetic fields formed by electromagnetic induction cancel each other out, thereby reducing stray inductance. In particular, the DC bus bar 530 has a plate-shaped upper surface 531, a side surface 533 bent downward from one end edge of the upper surface 531 and extending, and another end edge of the side surface 533. It is configured to include a lower surface 535 bent and extended in the same direction as the upper surface 531, and a fastening hole 537 coupled to the fastening member 550 is formed on the upper surface 531 and the lower surface 535, respectively. . That is, the DC bus bar 530 has a “c” shape.

In particular, when the DC bus bar 530 is coupled to the input P terminal 310 and the input N terminal 330, the side 533 of the DC bus bar 530 connected to the input P terminal 310 and the input N terminal The side surfaces 533 of the DC bus bar 530 connected to 330 are arranged to face each other, so that the side surfaces 533 are most adjacent to each other, and current flows in opposite directions when energized, resulting in a magnetic field formed by electromagnetic induction. This cancels out so that the stray inductance is reduced. The DC bus bar 530 connected to the input P terminal 310 and the DC bus bar 530 connected to the input N terminal 330 are mutually based on the partition wall 591 of the zone 510 of the terminal block case 590. It is installed symmetrically. The DC bus bar 530 coupled to the input P terminal 310 of the power module 300 and the DC bus bar 530 coupled to the input N terminal 330 of the power module 300 are It is installed in a shape that surrounds the terminal block case 590 at the point where the input P terminal 310 and the input N terminal 330 of the power module 300 are located from the outside, so that the side surfaces 533 of the DC bus bar 530 are closer than each other. installed adjacent to In particular, since the DC bus bar 530 can be assembled and used in opposite directions after being produced using one mold, production costs can be reduced and production efficiency can be increased.

Terminals of the input P terminal 310, the input N terminal 330, and the AC output terminal 350 of the power module 300 are plate-shaped, and through-holes 370 are formed in the terminals 310, 330, and 350 to form a fastening member 550. is interlocked by The input P terminal 310 and the input N terminal 330 of the power module 300 are electrically connected to the stacked power module units 900 by the DC bus bar 530 in the terminal block case 590, and the AC output terminal In 350, an insert ring 570, which is a conductor, is provided in the terminal hole 511 of the terminal case 590 to electrically connect the stacked power module units 900 to each other. It is preferable that the insert ring 570 is assembled by being press-fitted into the terminal hole 511 of the terminal stand case 590 .

Accordingly, a plurality of terminal block cases 590 are provided by being stacked between the capacitor 100 and the power module 300 . A terminal block 500, which is a conductor installed on the capacitor 100, is provided on the lowermost surface, and the output terminal 130 of the capacitor 100 is seated on the terminal block 500, and the fastening member 550 is installed vertically on the output terminal 130. is formed Here, a terminal case 590 is provided and stacked. After the DC bus bar 530 or the insert ring 570 is assembled in the terminal case 590, the terminals 310, 330, and 350 of the capacitor 100 are stacked. In particular, 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, so that the fastening member 550 ) is through-coupled to the terminal hole 511, the through-hole 370, and the fastening hole 537 at the same time, so that the capacitor 100 and the power module 300 are electrically connected. A nut 551 is fastened to the uppermost end of the fastening member 550 to solidify the fastening.

In the present invention, the current flow formed by contact between 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 the general current flow. On the other hand, the current formed by contacting the input P terminal 310 and the DC bus bar 530 and the input N terminal 330 and the bus bar of the power module 300 is formed in a symmetrical form so that the DC bus bar 530 is mutually By being formed into a shape, they flow in different directions, but flow at points close to each other.

In general, stray inductance is a resistance component formed by electromagnetic induction that occurs when current changes. However, as in the present invention, when currents flow in opposite directions, opposite magnetic fields are formed, and in particular, adjacent magnetic fields cancel each other out. Therefore, in the DC bus bar 530 connected to the input P terminal 310 of the terminal block 500 and the DC bus bar 530 connected to the input N terminal 330, a magnetic field is generated from current flowing in opposite directions, By being positioned close to each other, they cancel each other out, resulting in an effect of reducing stray inductance.

These details can be confirmed in detail in FIG. 7 . 7 is a graph in which stray inductance of the present invention and the related art is analyzed.

In general, when a plurality of power modules 300 are connected to the capacitor 100 in order to increase the output of the power converter, the physical connection distance becomes longer, and the connection distance between each power module 300 changes, increasing the stray inductance and stray An imbalance between inductances occurs. In this specification, by inserting a symmetrical “c”-shaped DC bus bar 530 into the terminal block case 590 connecting the power modules 300, stray inductance is reduced by canceling the magnetic field of currents flowing in opposite directions to each other do.

Analyzing the stray inductance of the conventional structure and the inverter structure according to an embodiment of the present invention, the stray inductance between the first-layer power module 300 and the second-layer power module 300 is reduced by 45% from 2.88nH to 1.59nH, It can be seen that the stray inductance between the first-layer power module 300 and the third-layer power module 300 is reduced by 60% from 6.89nH to 2.74nH. In addition, it can be seen that the difference in stray inductance between each layer of the power module 100 is 4.01 nH, which is a difference between 2.88 nH and 6.89 nH in the conventional structure, but is reduced by about 71% to 1.55 nH in the present invention.

The stray inductance causes a peak voltage to be generated when the current rapidly changes during the switching operation of the power module 300 and causes the power module 300 to burn out. Therefore, according to the inverter structure of the vehicle of the present invention as described above, there is an advantage in that the risk of burnout of the power module 300 can be reduced by improving the reliability and durability of the power module 300 . Therefore, since a higher current can be used in the power module 300, there is an effect of improving the output of the power converter compared to the prior art.

Although the present invention has been shown and described in relation to specific embodiments, it is known in the art that the present invention can be variously improved and changed without departing from the technical spirit of the present invention provided by the claims below. It will be self-evident to those skilled in the art.

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

Claims (11)

a capacitor receiving DC current from the high voltage battery;
A power module having an input P (Positive) terminal, an input N (Negative) terminal, and an AC output terminal, and is electrically connected to a capacitor to convert DC current received from the capacitor into three-phase AC current and output it; and
A plurality of DC buses located between the capacitor and the power module and coupled to the input P (Positive) terminal and the input N (Negative) terminal of the power module, respectively, to allow current to flow in different directions, thereby reducing stray inductance Including; bar;
When the DC bus bar is connected to the input P (Positive) terminal and the input N (Negative) terminal, one side of the DC bus bar connected to the input P (Positive) terminal and the other side of the DC bus bar connected to the input N (Negative) terminal face each other. By being arranged to see, it is installed so that current flows in opposite directions to each other when energized,
The DC bus bar is configured to include a plate-shaped upper surface, a side surface bent downward from one end corner of the upper surface and extended, and a lower surface bent and extended in the same direction as the upper surface again at one end edge of the side surface. Inverter structure of a characterized vehicle. The method of claim 1,
The capacitor has an input terminal for receiving DC current from the high voltage battery, and a plurality of output terminals for outputting smoothed current are provided on the power module side of the capacitor. The input P (Positive) terminal, the input N (Negative) terminal and An inverter structure of a vehicle, characterized in that a fastening member, which is a conductor, is provided at a point where an AC output terminal and an output terminal of the capacitor respectively meet. The method of claim 1,
A DC bus bar having a fastening hole is provided between the input P (Positive) terminal and the input N (Negative) terminal of the power module and the output terminal of the capacitor, and a fastening member extending upward is provided at the output terminal of the capacitor, respectively. Through-holes are formed at the input P (Positive) terminal, the input N (Negative) terminal, and the AC output terminal, respectively, and the fastening member is penetrated through and coupled to the fastening hole and the through-hole, respectively, so that the capacitor and the power module are electrically connected. Vehicle inverter structure. The method of claim 1,
Between the capacitor and the power module, a terminal block on which a terminal of the capacitor, a terminal of the power module, and a fastening member are disposed is provided, and the capacitor and the power module are fastened to each other in the terminal block to be electrically connected. Inverter structure of a vehicle. The method of claim 4,
The terminal block is provided with a non-conductive terminal block case that allows the terminals of the input P (Positive) terminal, the input N (Negative) terminal, and the AC output terminal of the power module to be coupled to the output terminal of the capacitor, respectively, and the terminal block case corresponds to the terminal one-to-one. An inverter structure of a vehicle, characterized in that zones are divided as much as possible. The method of claim 4,
The DC bus bar connected to the input P (Positive) terminal of the power module and the DC bus bar connected to the input N (Negative) terminal of the power module are the input P (Positive) terminal of the power module and the input N (Negative) terminal of the power module. An inverter structure of a vehicle, characterized in that it is installed in a shape surrounding the terminal block case at the position where it is located from the outside. The method of claim 4,
Terminal holes are formed in the terminal block case for fastening members to pass through, and through-holes are formed in the terminals of the input P (Positive) terminal, the input N (Negative) terminal and the AC output terminal of the power module, and the fastening holes are formed in the DC bus bar. The inverter structure of a vehicle characterized in that the terminal hole, the through hole and the fastening hole are disposed to communicate with each other so that the fastening member is simultaneously penetrated and coupled to the terminal hole, the through hole and the fastening hole. The method of claim 7,
An inverter structure of a vehicle, characterized in that an insert ring, which is a conductor, is provided in the terminal hole of the terminal block case where the AC output end of the power module is located, and a fastening member is penetrated through the insert ring. The method of claim 1,
On the upper and lower surfaces of the DC bus bar, fastening holes that are fastened with fastening members are formed, respectively.
An inverter structure of a vehicle, characterized in that one side of the DC bus bar connected to the input P (Positive) terminal and one side of the DC bus bar connected to the input N (Negative) terminal correspond to side surfaces. delete The method of claim 1,
The power module is in the form of a plate, and a plurality of power module units are provided to form three rows of power module units. Inverter structure of a vehicle, characterized in that the cooler is located at the outermost outermost part of the upper and lower sides.

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