JPH11225485A - Power converter circuit and motor-driven apparatus therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To integrate a power converter circuit and an AC motor for size reduction suited to vehicle-mounting, by placing a power converting semiconductor element and its AC side output terminal boards respectively at such a position as the respective pairs are almost equally-placed with regard to an electrolytic capacitor, between respective bus bars for wiring. SOLUTION: A capacitor storage part 24 is formed in the center of a power converter circuit integrated part of a case 22, and power converting sections 25u, 25v, 25w of three phases U, V, W are formed respectively at the periphery thereof. Bus bars uB+, uB-; vB+, vB-; wB+, wB- for the positive and negative wiring of the respective phases are placed in radial form to the power converting sections 25u, 25v, 25w of the respective phases. Sector-shaped AC side output terminal boards 27u, 27v, 27w are formed in the circumferential center part of the power converting sections 25u, 25v, 25w of the respective phases. All of the mounting positions of the output terminal boards of the respective phases 27u, 27v, 27w are at equal distances from the center of the capacitor storage part 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power conversion circuit for converting a DC power supply into a three-phase AC, and a motor driving device using the same.

[0002]

2. Description of the Related Art In general, a power conversion circuit used in an electric vehicle has a circuit configuration shown in FIG. 7, and a filter circuit 2 composed of L and C for removing high frequency, An inverter circuit 4 for quadrature power conversion is connected via a capacitor 3, and a three-phase U, V, W output of the inverter circuit 4 is supplied to a driving induction motor 5. Then, the inverter circuit 4 includes U, V, W
One set of IGBT elements 4au, 4bu for each phase;
4aw, 4bw, 4av, 4bv are installed, and these I
The AC output of each phase of U, V, W is taken out from the middle point au, av, aw of the GBT element, and the input terminal b of the three-phase induction motor 5 is obtained.
u, bv, and bw.

[0003] In the case of an electric vehicle, a large current flows through the power conversion circuit. In order to reduce the current resistance as much as possible, the structure shown in FIG. A power conversion circuit is employed.

[0004] The structure of this conventional power conversion circuit will be described. Copper bus bars are laminated with an insulating sheet between them, an electrolytic capacitor 3 is placed on the bus bar laminated structure 11, and a bus bar laminated structure is formed. This is a structure in which IGBT modules 4u, 4v, and 4w are installed below the structure 11. In the bus bar laminated structure 11, reference characters uB +, vB +, and wB + denote the batteries 1 respectively.
Are connected to the + side of the filter circuit 2 and the electrolytic capacitor 3 via the electrolytic capacitor 3, and the reference numerals uB-, vB- and wB- are connected to the negative side of the battery 1 via the filter circuit 2 and the electrolytic capacitor 3; Symbols au, av, and aw represent output ends of the IGBT elements 4u, 4v, and 4w from the middle points au, av, and aw of the IGBT elements, respectively.

The bus bar laminated structure 11 and each IGB
The electrical connection between the T modules 4u, 4v, 4w is as shown in FIG. 9 (here, only the U phase is shown as a representative, but the V and W phases are the same). First, in the IGBT module 4u, an IGBT semiconductor chip 13 is soldered on a ceramic substrate 12 having conductor patterns on both surfaces, and an aluminum wire 14 is bonded between the conductor pattern on the ceramic substrate 12 and a pad on the semiconductor chip 13. . Ceramic substrate 1
2 is soldered on the metal base 15. further,
Input terminals 16u +,
16u- and the output terminal 16au are soldered to the conductor pattern on the ceramic substrate 12, and the terminal portions uB +, uB- and the midpoint terminal au on the side of the bus bar laminated structure 11 are connected to these. .

[0006]

In such a conventional power conversion circuit, a metal busbar laminated structure 11 is used to allow a large current to flow. AC output terminals au, a
The current path leading to v and aw is not uniform among the U, V and W phases, and the wiring inductance varies, and the current path from the electrolytic capacitor 3 in the DC power input section to the IGB
The path from the semiconductor chip 13 to the induction motor 5 in the T modules 4u, 4v, and 4w and the path from the semiconductor chip 13 to the induction motor 5 are long, and the wiring inductance is large, so that the switching surge voltage generated in proportion to the wiring inductance is absorbed. However, there is a problem that the snubber circuit as the protection circuit becomes large.

The present invention has been made in view of such conventional problems, and a current path from an electrolytic capacitor to an AC output terminal via a semiconductor element is uniform in each of U, V, and W phases, and wiring inductance is uniform. And the path from the electrolytic capacitor to the power conversion semiconductor element of each phase of U, V, and W, and the path from the power conversion semiconductor element to the output terminal on the AC motor side are short, and the wiring inductance is small. It is an object of the present invention to provide a power conversion circuit having a structure in which a circuit is not required or a snubber circuit can be downsized even when required.

Another object of the present invention is to provide a motor drive device having such a structure that the power conversion circuit and the AC motor are integrated and can be made compact and suitable for mounting on a vehicle.

[0009]

According to a first aspect of the present invention, there is provided a power conversion circuit having an electrolytic capacitor installed at a central portion, and three sets of wiring bus bars extending from positive and negative bus bars for a DC power supply around the capacitor. The power conversion semiconductor device and its AC output terminal plate are arranged radially between the three sets of positive and negative wiring bus bars at positions where each set is substantially equidistant about the electrolytic capacitor. It is.

According to a second aspect of the present invention, in the power conversion circuit of the first aspect, the power conversion semiconductor element is wire-bonded to the wiring bus bar and the AC side output terminal plate.

In the power conversion circuit according to the first and second aspects of the present invention, the three-phase DC power supply bus bar, the AC side output terminal plate, and the power conversion semiconductor element are arranged radially around the central electrolytic capacitor. Since the layout is almost equidistant from the electrolytic capacitor, the current path from the electrolytic capacitor through the semiconductor element to the AC output terminal is uniform in each of the U, V, and W phases, and there is no variation in wiring inductance. Because of the arrangement, the distance between the wiring bus bar of each phase and the semiconductor element for power conversion is shortened, so that the path from the electrolytic capacitor to the semiconductor element for power conversion of each phase of U, V and W, and the semiconductor for power conversion The path from the element to the output terminal on the AC motor side is short, wiring inductance is reduced, and switching surge can be reduced.
Further, the snubber circuit which has been required in the related art can be omitted, or a small-sized snubber circuit can be used even when a snubber circuit is used.

According to a third aspect of the present invention, there is provided an electric motor drive device comprising the power conversion circuit according to the first or second aspect, and the power conversion circuit is combined with a three-phase AC motor, and each of the AC side output terminal plates is connected to the three-phase AC motor. It is electrically connected to each phase input terminal of the phase AC motor, and has a compact structure suitable for vehicle mounting.

[0013]

According to the first and second aspects of the present invention,
The current path from the electrolytic capacitor through the semiconductor element to the AC output terminal is uniform in each of the U, V, and W phases, and there is no variation in wiring inductance.
The path from the semiconductor element for power conversion of each phase of V and W, and the path from the semiconductor element for power conversion to the output terminal on the AC motor side are short, the wiring inductance is reduced, and the switching surge can be reduced. A small snubber circuit can be omitted or a small one can be used even when a snubber circuit is used.

According to the third aspect of the present invention, since the power conversion circuit and the AC motor are combined, a compact structure can be achieved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 show one embodiment of the power conversion circuit of the present invention. The power conversion circuit 20 of this embodiment is housed in a case 22 together with the high-frequency removal filter circuit 2 composed of L and C. Case 2
2 is a DC input terminal 2 for connecting to a battery power source.
3+ and 23− are provided, and a DC power is input to the filter circuit 2 from these DC input terminals 23+ and 23−.

A capacitor accommodating portion 24 is formed at the center of the power conversion circuit built-in portion of the case 22, and U,
V, W three-phase power conversion sections 25u, 25v, 2
5w is formed. Power conversion section 25u, 2 for each phase
5v and 25w have positive and negative wiring bus bars uB +,
uB−; vB +, vB−; wB +, wB− are radially arranged, and these + side wiring busbars uB +, vB−
B +, wB +, − side wiring busbar uB−, vB−, w
The central ends of B- are connected to the center connecting portions 26+, 26- at the bottom of the capacitor accommodating portion 24. The central connecting portions 26+ and 26- are connected to the output terminals 21+ and 21- of the filter circuit 2 using the wiring bus bars wB + and uB-, respectively.

The power conversion sections 25u, 25v, 25 of each phase
At the center in the circumferential direction of w, fan-shaped (although not particularly limited to this shape) AC output terminal plates 27u, 27v,
27w are formed. And the power conversion section 2 of each phase
5u, 25v, 25w, + side wiring bus bar u
B +, vB +, wB + and output terminal plates 27u, 27v, 2
IGBT modules 28u +, 28v +, and IGBT elements for power conversion integrated in portions sandwiched between
28w + are disposed, and bus bars uB-,
An IGBT module 28u is provided on each of the portions sandwiched between vB−, wB− and the output terminal plates 27u, 27v, 27w.
, 28v- and 28w- are arranged. Each IGBT
Modules 28u +, 28v +, 28w +, 28u-,
IGBT elements are incorporated in 28v- and 28w-, between the IGBT elements and the wiring bus bars on the + and-sides of each phase, and between the IGBT elements and the output terminal plates 27u, 27v, 27w is electrically connected by bonding of a wire 29 (note that in FIG. 1, only the U-phase portion is
, But are similarly bonded to each phase).

The output terminal plates 27u, 27 for each of these phases
The mounting positions of v and 27w are both
Of the IGBT modules 28u +, 28v +, 28w +, 28u-, 2
8v- and 28w- at both positions
4 are located at the same distance from the center.

A heat sink 30 is mounted on the bottom surface of the case 22, and the bottom surface of each IGBT module 28 comes into contact with the heat sink 30. That is, as shown in FIG. 3, each IGBT module 28 has a structure in which a semiconductor chip 28c is mounted on a ceramic substrate 28a by soldering 28b, and when the IGBT module 28 is incorporated into the power conversion circuit 20,
Soldering 31 so that the back surface of ceramic substrate 28a of BT module 28 directly contacts heat sink 30.
It is fixed.

The power conversion circuit 20 having the above configuration is used by being integrally assembled on the three-phase induction motor 5. That is, as shown in FIG. 1, FIG. 2, and FIG.
0 is applied to the head of the three-phase induction motor 5 and screwed into the terminal hole 35 on the side of the motor 5 through the connection screw 33 through the terminal hole 27a of each of the output terminal plates 27u, 27v, 27w. Power conversion circuit 20
Is combined with the induction motor 5, and the electrical connection is completed at the same time.

The structure of the coupling portion between the power conversion circuit 20 and the induction motor 5 will be described with reference to FIG. 5 (note that although the figure shows the U-phase portion, the V- and W-phases have the same structure. is there). The connection screw 33 is inserted into the terminal hole 27a of the output terminal plate 27u, and is inserted and screwed into the terminal hole 35 on the induction motor 5 side. Inside the terminal hole 35 of the induction motor 5, a terminal fitting 39 in which a crimp terminal portion 37 for crimping an end of an input power cable 36 of the induction motor and a female screw portion 38 are fixed and connected. The screw 33 is screwed into the female screw portion 38 by screwing, so that electrical connection can be made simultaneously with the mechanical integration of the power conversion circuit 20 and the induction motor 5.

The coupling structure between the power conversion circuit 20 and the induction motor 5 is not limited to this, and as shown in FIG.
A terminal fitting 39 in which a crimp terminal portion 40 obtained by crimping an end of an input power cable 36 of the induction motor and a male screw portion 41 are fixed inside the terminal hole 35 of the induction motor 5 and are combined. , The male screw portion 41 may be inserted into the terminal hole 27a of the output terminal plate 27u on the power conversion circuit 20 side and tightened by the nut 43.

As described above, the power conversion circuit 2 of the present invention
0, each phase U, V,
By laying out the wiring busbars of W and the IGBT module radially and at substantially the same distance from the electrolytic capacitor 3, the current path from the electrolytic capacitor 3 through the semiconductor element to the AC output terminal is U,
Since the wiring inductance is uniform in each of the V and W phases, and the semiconductor element of the IGBT module 28 is wire-bonded to the + and-wiring bus bars, the U, V, and W components are removed from the electrolytic capacitor 3. The wiring inductance can be reduced by shortening the path from the semiconductor element for power conversion of the phase and the path from the semiconductor element for power conversion to the output terminal on the induction motor side, thereby reducing the switching surge. Even if the snubber circuit is omitted or a snubber circuit is used, a small one can be used.

Further, in the above-described power conversion circuit 20, a three-phase AC electrical connection can be made to the induction motor 5 and at the same time a mechanical connection can be made, so that the compactness useful as a vehicle-mounted motor driving device can be achieved.

In the above embodiment, a three-phase induction motor is used as the motor, but the present invention is not limited to this, and a three-phase synchronous motor may be used.

[Brief description of the drawings]

FIG. 1 is a plan view of a power conversion circuit according to one embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a sectional view showing an attachment structure of the IGBT module according to the embodiment.

FIG. 4 is an exploded perspective view showing a method of connecting the power conversion circuit of the embodiment to an AC motor.

FIG. 5 is a sectional view showing a method of coupling the power conversion circuit and the AC motor.

FIG. 6 is a sectional view showing another example of a method of coupling the above-described power conversion circuit and an AC motor.

FIG. 7 is a circuit diagram of a general power conversion circuit.

FIG. 8 is a perspective view showing the structure of a conventional power conversion circuit.

FIG. 9 is a cross-sectional view of an IGBT module in a conventional power conversion circuit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Battery 2 Filter circuit 3 Electrolytic capacitor 5 Induction motor 20 Power conversion circuit 22 Case 23+, 23- DC power supply input terminal 25u, 25v, 25w Power conversion division 26+, 26- Central connection part 27u, 27v, 27w Output terminal board 27a terminal Holes 28u +, 28u-, 28v +, 28v-, 28w +,
28w- IGBT module 30 heat sink 33 connection screw 35 terminal hole 36 cable 37 crimp terminal 38 female screw 39 terminal fitting

Claims (3)

[Claims] 1. An electrolytic capacitor is installed at a central portion, three sets of wiring busbars extending from positive and negative busbars for a DC power supply are radially arranged around the capacitor, and between the three sets of positive and negative wiring busbars. A power conversion circuit comprising: a power conversion semiconductor element and an AC output terminal plate each disposed at a position where each set is substantially equidistant from the electrolytic capacitor. 2. The power conversion circuit according to claim 1, wherein the power conversion semiconductor element is wire-bonded to the wiring bus bar and the AC output terminal plate. 3. The three-phase AC motor, wherein the power conversion circuit is combined with a three-phase AC motor, and each of the AC-side output terminal boards is electrically connected to each phase input terminal of the three-phase AC motor. Or a motor drive device using the power conversion circuit according to 2.