JP2003299366A - Power converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that inductance is large, the suppression of a surge by a smoothing capacitor is insufficient, wiring resistance is large, and the drop of a voltage at power conversion is large. <P>SOLUTION: A first input bus bar 25, a second input bus bar 30 and a plurality of bus bars 41, 44 and 47 each made of a single member are embedded in a housing case 15 made of a resin. A positive terminal P, high-level terminals 85a and 85b of smoothing capacitors 85 and 86 and high-level terminals of semiconductor elements 56 to 66 are energized by the first bus bar 25. A negative terminal N, low-level terminals 85b and 86b of the smoothing capacitor and low-level terminal of the semiconductor element are energized by the second input bus bar 30. The semiconductor terminal and an AC motor 55 are energized by the plurality of output bus bars 41 and the like. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power conversion device for mutually converting power between direct current and alternating current.

[0002]

2. Description of the Related Art For example, in an electric vehicle (hybrid vehicle) that uses electricity as a part of a power source, a three-phase AC motor that is structurally robust and easy to control is used as an electric power source. On the other hand, since the battery is a DC power source, a power converter is used to mutually convert power between DC power and AC power.

FIG. 10 shows the concept of a power conversion system.
The power conversion device 100 is interposed between the battery 150 and the three-phase AC motor 155 and is functionally and structurally the power conversion unit 1.
02, the smoothing capacitor 120, the control unit 125,
It is roughly divided into a storage case 130.

Of these, the power converter (inverter circuit)
As shown in FIG. 11, reference numeral 102 denotes a resin case module 104, a heat dissipation plate 111 housed in the module 104, and six semiconductor elements 112a to 112f mounted on the heat dissipation plate 111. , And a circuit board 113 having a drive circuit for driving the semiconductor elements 112a to 112f. Embedded in the module 104 are an internal input high busbar 105, an internal input lowbusbar 106, and three internal output busbars 106, 107 and 108.

The smoothing capacitor 120 is a power conversion unit 10.
It is connected in parallel between the two input terminals and suppresses the voltage fluctuation (surging) of the battery 150 at the time of switching,
Smooths voltage jumps, etc. Control unit (control circuit) 12
5 is connected to the power converter 102 by a signal wire 161 and outputs a control signal to the power converter 102 to control the switching operation.

The storage case 130 is made of aluminum, and has a power converter 102, a smoothing capacitor 120, and a controller 1.
Holds 25. Power converter 100 and battery 1
The high-level side connection point 132 (P input point) and the low-level side connection point 133 (N input point) with the wiring from 50 and the power conversion unit 102.
An external input high level bus bar 141 and an external input low level bus bar 142 are attached between and. Connection points 136 (U-phase output point), 137 (V-phase output point) and 13 between power converter 100 and wiring from three-phase AC motor 155
8 (W-phase output point) and the power converter 102, a U-phase external output bus bar 146 and a V-phase external output bus bar 147.
And a W-phase external output bus bar 148 is attached.

The external input high level bus bar 141 has a connection point 13
2 and the power conversion unit 102 are connected, and branched and connected to the high-level terminal 121 of the smoothing capacitor 120. Similarly, the external input low level bus bar 142 is connected to the low level terminal 122 of the smoothing capacitor 120.

Next, the storage case 130, and the power converter 102 and the smoothing capacitor 1 housed inside the storage case 130.
The conduction with 20 will be described. As shown in FIG.
The external input high bus bar 141 having the connection point 132 is connected to the internal input high bus bar 105 of the module 104 and the screw 14.
It is screwed with the screw 5, and branched in the middle, and screwed with the screw 146 to the high-level side terminal 121 of the smoothing capacitor 120. The external input low level bus bar 142 having the connection point 133 and the internal input low level bus bar 106 also branch in the middle and are similarly screwed.

Further, a U-phase output point 136 and a V-phase output point 13
External output busbar 14 having 7 and W-phase output points 138
6, 147 and 148 and the internal output three-phase bus bar 106,
107 and 108 are fixed by screws (not shown).

The "inside" means the inside of the module 104, and the "outside" means the outside of the module 104, that is, between the module 104 and the storage case 130.

The power converter 100 drives the three-phase AC motor 155 by converting the discharge output of the battery 150 from DC to three-phase AC when starting the gasoline engine. On the other hand, during normal traveling, the three-phase AC motor 155 is rotated by using a part of the power of the gasoline engine, the three-phase AC generated by the three-phase AC motor is converted into DC, and the battery 150 is charged.

[0012]

However, it has been found that the above-mentioned conventional example has room for improvement in the following points.

First, there is a problem due to the use of a large number of bus bars 105 and 106, 141 and 142 that electrically connect between the power converter 102 and the smoothing capacitor 120 and the storage case 130. That is, the smoothing capacitor 12
0 and the semiconductor devices 120a to 120f between the external input high level bus bar 141 and the external input low level bus bar 142.
And the internal input high level bus bar 105 and the internal input low level bus bar 106 intervene.

Therefore, the inductance between the smoothing capacitor 120 and the semiconductor elements 112a to 112f is large, and the effect of suppressing the surge by the smoothing capacitor 120 tends to be small. Not only many bus bars 10
The use of 5 and 106, 141 and 142 tends to increase the number of parts.

Second, the input terminals (P input point 132 and N
There is a problem due to the large number of screws 145 and the like used for connecting the bus bar from the input point 133) to the output terminals (U-phase output point 136, V-phase output point 137, and W-phase output point 138). This is associated with three defects.

First, the contact resistance between the large number of bus bars 105, 141 and the like and the large number of screws 145 and the like is large, and the voltage drop becomes large when the DC voltage is converted into the AC voltage. With this, it is difficult to obtain a large torque in the three-phase AC motor 155.

Next, it is necessary to secure a space in the storage case 130 for screwing the bus bars 105, 141 and the like with screws 145 and the like. As a result, the storage case 130, the smoothing capacitor 120, and the power conversion unit 102.
The interval between them tends to be large.

In particular, when the distance between the power conversion unit 102 and the smoothing capacitor 120 becomes large, the bus bars 105 and 106, 141 and 142 for conducting the two become long,
Inductance and conduction resistance tend to increase. Increasing the inductance tends to reduce the surge suppression effect. On the other hand, the increase in conduction resistance lowers the voltage that can be output with respect to the input voltage, and even if an attempt is made to rotate the three-phase AC motor 155 with a low-voltage power source such as an auxiliary battery, the voltage is sufficient for the motor winding. No voltage can be applied. With this, the magnitude of the torque generated by the three-phase AC motor 155 tends to be insufficient.

Finally, the coupling of the bus bars 105, 141 and the like with the screws 145 and the like is a fine work in a narrow space of the storage case 130, and it takes time and labor to screw them.

Thirdly, by adopting the module 104 and arranging the external input high-order bus bar 141, the external input low-order bus bar 142, and the external output three-phase bus bars 146 to 148, the power converter can be operated in the vertical, horizontal and height directions. The dimension of is likely to be long. This is not desirable in vehicles where the space available for power converters is limited.
Further, the aluminum storage case 130 has a heavy weight and is inconvenient to handle.

Further, since the storage case 130 is made of aluminum, a gap for insulation is required between the external input bus bars 141, 142 and the external output bus bars 136, 137, 138 and the storage case 130.
These voids have caused a further increase in size and weight of the power conversion device.

[0022]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, in which surge suppression is favorably performed by a smoothing capacitor, a voltage drop during power conversion is small, and an inductance and a conduction resistance are reduced. An object is to provide a power conversion device whose increase is suppressed as much as possible. Another object of the present invention is to provide a power conversion device having a small overall volume, a light weight, and easy assembly.

The inventor of the present application has attributed the problem in the conventional example to the fact that the storage case is made of aluminum and the power conversion section is modularized, and then the storage case and the power conversion section are electrically connected by a large number of bus bars. I got the knowledge. Then, as a result of earnest research on a method for reducing the number of bus bars, the present invention has been completed by thinking of embedding the bus bars in a resin storage case.

The power converter of the present invention is, as described in claim 1, interposed between a DC power supply and an AC motor,
A power conversion device for converting direct current into alternating current and converting alternating current into direct current, comprising a plurality of semiconductor elements and mutually converting power between direct current and alternating current; A smoothing capacitor that smoothes the output of the DC power supply that is supplied; a control unit that controls the switching operation of each semiconductor element; a first housing unit that houses the power conversion unit; and a second housing unit that houses the smoothing capacitor. A storage case made of resin having: a positive terminal electrically connected to the high-level side of the DC power supply; and a first terminal electrically connected to the high-level terminal of the smoothing capacitor.
A first input busbar that is embedded in a housing case and that has a capacitor terminal and a plurality of first semiconductor terminals that are electrically connected to the high-level terminals of each semiconductor element, and a negative terminal that is electrically connected to the low-level side of the DC power supply. And a second capacitor terminal that is electrically connected to the low-level terminal of the smoothing capacitor and a plurality of second semiconductor terminals that are electrically-conductive to the low-level terminals of the respective semiconductor elements, which are made of a single member and are embedded in the storage case. A bus bar; a plurality of output bus bars each having a first end electrically connected to the semiconductor element and a second end electrically connected to the AC motor, which are formed of a single member, and are embedded in the housing case; It is characterized by

In this power converter, the power converter converts the DC power of the DC power supply into AC power and the AC power generated by the AC motor into DC power. The smoothing capacitor suppresses the surge at that time, and the control unit controls the switching operation of the semiconductor element.

The first and second input busbars electrically connect the high side and the low side of the smoothing capacitor and the high side and the low side of the semiconductor element of the power conversion unit, respectively, that is, without interposing other busbars. Further, the first and second input busbars electrically connect the positive and negative terminals to the high side and the low side of the semiconductor element of the power conversion unit, respectively, that is, without interposing other busbars. Further, the plurality of output busbars electrically connect the semiconductor element and the output terminal of the power conversion device directly, that is, without passing through other busbars.

As a result, the distance from the positive and negative input terminals to the semiconductor element and the distance from the semiconductor element to the output terminal can be shortened, and the connection resistance generated at the bus bar connecting portion can be reduced, so that the AC motor can be used. The voltage that can be supplied can be increased.

It is known that the bus bar is embedded in a resin-made storage case (for example, Japanese Patent Laid-Open No. 2001-2001).
No. 186778). However, a bus bar having the requirements of claim 1 is not known.

According to a second aspect of the present invention, there is provided the power conversion device according to the first aspect, wherein the first storage portion and the second storage portion of the storage case are arranged in an area that does not overlap each other in plan view. According to this power converter, a smoothing capacitor having a large electrostatic capacity can be used, and thus surge can be suppressed better.

According to a third aspect of the present invention, there is provided the power conversion device according to the first aspect, wherein the first input bus bar has an elongated shape, a positive terminal is provided at one end, a first capacitor terminal is provided at one side, and a plurality of first semiconductors is provided at the other side. The terminals are formed. According to this power converter, the positive terminal, the first capacitor terminal, and the first member are provided on the single member.
The semiconductor terminal can be efficiently formed. Further, the distance between the smoothing capacitor and the power conversion unit can be shortened, and the inductance and conduction resistance between the smoothing capacitor and the semiconductor element are reduced, so that the surge voltage suppressing effect is enhanced.

According to a fourth aspect of the present invention, there is provided the power converter according to the first aspect, wherein the second input busbar has an elongated shape and has a negative terminal at one end, a second capacitor terminal at one side, and a plurality of second semiconductors at the other side. The terminals are formed. According to this power converter, the negative terminal, the second capacitor terminal and the second
The semiconductor terminal can be efficiently formed. Further, the distance between the smoothing capacitor and the power conversion unit can be shortened, and the inductance and conduction resistance between the smoothing capacitor and the semiconductor element are reduced, so that the surge voltage suppressing effect is enhanced.

According to a fifth aspect of the power conversion device of the second aspect or the third aspect, the first input busbar and the second input busbar are arranged so as to overlap each other in a plan view. According to this power conversion device, the first input busbar and the second input busbar can be embedded in the storage case with good space efficiency, that is, without increasing the height. Moreover, a capacitor (stray capacitance) can be formed between the first input busbar and the second input busbar by interposing a resin that can be a dielectric leaving a slight thickness therebetween. for that reason,
The inductance of the smoothing capacitor and the power conversion unit can be reduced, and the inductance and conduction resistance between the smoothing capacitor and the semiconductor element are reduced, so that the surge voltage suppressing effect is enhanced.

According to a sixth aspect of the present invention, there is provided the power conversion device according to the first aspect, wherein the plurality of output busbars are insulated from each other in a region where they do not overlap each other in plan view. According to this power converter, when the output bus bar is embedded in the resin storage case, the output bus bar can be easily set in the molding die, and the productivity is improved.

According to a seventh aspect of the present invention, there is provided the power conversion device according to the fifth aspect, wherein the storage case has a bottom portion and a plurality of side wall portions.
The input bus bar and the second input bus bar are embedded from the first side wall to the bottom. According to this power conversion device, since the input busbar can be stored in the side wall portion and the bottom portion of the storage case, insulation can be ensured, and the inside of the storage case can be released to store other components. Further, since the input terminal block can be formed integrally with the case without separately providing the input terminal block, the number of parts and the number of assembling steps are reduced.

According to a sixth aspect of the power conversion device of the present invention, the storage case has a bottom portion and a plurality of side wall portions, and the plurality of output bus bars are buried from the second side wall to the bottom portion. According to this power conversion device, as in the case of claim 7, insulation can be ensured because the input busbar can be stored in the side wall portion and the bottom portion of the storage case, and the inside of the storage case is released to store other components. it can. Moreover, since the output terminal block can be formed integrally with the case without separately providing the output terminal block, the number of parts and the number of assembling steps are reduced.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION <Power Converter> The power converter is arranged between a DC power supply and an AC motor. The voltage of the DC power supply in the present invention is 8V to 16V, and the AC voltage modulated by PWM is applied to the AC motor. Therefore, P
The instantaneous voltage at which the motor is ignited by the WM on-pulse ideally becomes the DC power supply voltage. However, the DC power supply voltage is not limited to the above voltage value. The AC motor is preferably a three-phase AC motor, but is not limited to this.

Power conversion between DC power and AC power is required in electric vehicles and hybrid vehicles using an AC motor as auxiliary power for gasoline engines.

It is desirable that the plurality of semiconductor elements are field effect transistors (MOSFETs) in terms of on-resistance (conduction resistance) in the semiconductor element portion. However, in addition to this, the semiconductor element can be calibrated by an IGBT, a thyristor or the like by the voltage of the DC power supply. <Smoothing Capacitor> As a smoothing capacitor, an electrolytic capacitor is preferable because it has a small physical size with respect to the required capacity. However, in addition to this, a film capacitor, a ceramic capacitor, an electric double layer capacitor or the like can be adopted. It is desirable that the number is two to three in order to bring the semiconductor element and the smoothing capacitor close to each other. The capacity is required to be several hundreds to several thousands μF, and is appropriately determined according to specifications such as DC input voltage and output current. <Storage Case> As the resin material, PBT (polybutylene terephthalate), PPS (polyphenylene sulfide) or the like can be adopted. These resin materials are excellent in strength, heat resistance and insulation.

It is desirable that the first accommodating portion for accommodating the smoothing capacitor is a concave portion, but it is not limited to this. The second storage unit that stores the power conversion unit is preferably an opening, but is not limited to this.

"The first storage portion and the second storage portion do not overlap each other in plan view" means that they do not substantially overlap each other. Therefore, in addition to the case where they do not overlap at all, a part thereof may overlap. As a result of the disposition of the first and second storage portions, the smoothing capacitor and the semiconductor element are disposed in the storage case without overlapping in plan view. In addition, that the storage case has the second storage section that stores the power conversion section means that the power conversion apparatus of the present invention does not include the module in the conventional example. <Input Bus Bar> The first input bus bar may have a positive terminal connected to a DC power supply, at least one first capacitor terminal, and at least two first semiconductor terminals. It is desirable to have an elongated shape as a whole, and it is desirable to form the first capacitor terminal and the first semiconductor terminal on opposite side edges of the elongated portion.

The second input bus bar may have a negative terminal connected to the DC power supply, at least one second capacitor terminal, and at least two second semiconductor terminals. It is desirable to have an elongated shape as a whole, and it is desirable to form the second capacitor terminal and the second semiconductor terminal on opposite side edges of the elongated portion.

"Overlapping the first input busbar and the second input busbar in plan view" means substantially overlapping,
In most cases (60% to 90%), the overlap may be about half. The first input busbar and the second input busbar are embedded in, for example, a first wiring portion located between the first storage portion and the second storage portion, and are insulated by the first wiring portion.

The first and second input bus bars are made of copper (C
u) or aluminum (Al), which is a thin metal plate having excellent conductivity. <Output busbar> 1st (U phase), 2nd (V phase) and 3rd
The (W-phase) output busbars are embedded in a storage case close to the power conversion unit and insulated from each other. One end of each of the first to third output bus bars is electrically connected to each semiconductor element of the power conversion unit by wire bonding or the like, and the other end is connected to the AC motor.

The first to third output bus bars are made of copper (C
u) or aluminum (Al), which is a thin metal plate having excellent conductivity.

[0045]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment in which the present invention is applied to a power conversion system for a hybrid vehicle will be described below with reference to the accompanying drawings. <Structure of Embodiment> As shown in FIG. 1, the power conversion system includes a general-purpose DC power supply (battery) 150, the power conversion device 10 according to the present invention, and a general-purpose three-phase AC motor 115. The output of the battery 150 is 8 to 16V.

The power conversion device 10 includes a storage case 15 and a storage case 6.
Power converter 55 having individual MOSFETs 56 to 66
And smoothing capacitors 85 and 86, and a control unit 97. (Storage case, bus bar, etc.) As shown in FIG. 2, the storage case 15 includes a resin case body 16 and a case body 1.
5 bus bars 25, 30, 41, 4 buried in 6
4 and 47 and a lid (not shown). Case body 1
6 is a rectangular bottom portion 17, the first side wall 18a, the second side wall 1
8b, a third side wall 18c and a fourth side wall 18d. The bottom portion 17 is a recess (first storage portion) 21 on the side of the fourth side wall 18d.
And an opening portion (second storage portion) 22 on the side of the third side wall 18c. The recess 21 has a rectangular shape, and the bottom surface projects downward as shown in FIG. The opening 22 has a rectangular shape,
It penetrates in the thickness direction. The first wiring portion 23 is located between the recess 21 and the opening 22, and the third side wall 18c and the opening 2 are disposed.
The second wiring portion 24 is located between the second wiring portion 24 and the second wiring portion 24.

As shown by the broken line in FIG. 2, the first wiring portion 23
The first input busbar (high-order busbar) 25 and the second
An input busbar (low-order busbar) 30 is embedded. The first input bus bar 25 has an elongated rectangular portion 26 and a bent portion 27 on one end (left end) side thereof. The rectangular portion 26 extends laterally to one side and is exposed on the surface of the first wiring portion 23. The first terminal (first semiconductor terminal) 26a, the second terminal 26b, and the third terminal 26b.
The terminal 26c is provided, and the other side is provided with a fourth terminal (first capacitor terminal) 26d and a fifth terminal 26e that are bent upward and are exposed at the side edge of the recess 21. The P terminal 28 formed at the tip of the bent portion 27 is exposed on the side surface of the first side wall 18a.

The second input busbar 30, like the first input busbar 25, has an elongated rectangular portion 31 and a bent portion 32 on one end side thereof. The rectangular portion 31 extends laterally to one side and is exposed on the surface of the first wiring portion 23. The first terminal (second semiconductor terminal) 3
1a, a second terminal 31b and a third terminal 31c are provided, and a fourth terminal (second capacitor terminal) 31d and a fifth terminal 31e which are bent upward to the other side and exposed at the side edge of the recess 21 are provided.

First terminal 31a, second terminal 31b and third terminal
The terminal 31c is the first terminal 26a of the first bus bar 25, the second terminal
It is adjacent to the terminal 26b and the third terminal 26c. Also,
The fourth terminal 31d and the fifth terminal 31e are the first bus bar 25.
It is adjacent to the fourth terminal 26d and the fifth terminal 26e.
The N terminal 33 formed at the tip (left end) of the bent portion 32 is exposed adjacent to the P terminal 28 on the side surface of the first side wall 18a.

The first bus bar 25 and the second bus bar 30
Are slightly separated from each other in the vertical direction, are embedded in the first wiring portion 23 so that most of them overlap in a plan view, and are insulated from each other by the first wiring portion 23.

As shown in FIGS. 3 and 7, the opening 22 has a rectangular plate-shaped heat dissipation plate 3 made of an alloy containing copper as a main component.
5 is placed. The fins 38 are provided on the lower surface of the heat sink 35.
Is attached. Three output bus bars 41, 44 and 47 are embedded in the second wiring portion 24. The first output busbar (U-phase busbar) 41 includes a horizontal portion 42a and a vertical portion 42b, and has an L-shape as a whole. The horizontal portion 42a is embedded in the second wiring portion 24, and the tip thereof forms the U-phase terminal 43. The vertical portion 42b is located at the side edge of the opening 22.

Second output bus bar (V phase bus bar) 44
Has a shape similar to that of the first output bus bar 41, and is embedded in the second wiring portion 24 and has a horizontal portion 45 a having a tip formed with the V terminal 46 and a vertical portion 45 b located at the side edge of the opening 22.
Have. The third output bus bar (W-phase bus bar) 47 has a shape similar to that of the first output bus bar 41, is embedded in the second wiring portion 24, and has a horizontal portion 48 a whose tip forms the W-phase terminal 49 and the opening 22. Vertical part 48b located on the side edge of
Have.

In addition, first to third signal terminal groups 51a to 51c and first to third signal terminal groups 52a to 52c are erected on the first and second wiring portions 23 and 24. There is. Each signal terminal group includes five signal terminals. Further, a connector 53 is formed on the fourth side wall 18d. (Power Converter) As shown in FIGS. 3 and 6, the power converter (three-phase inverter circuit) 55 includes six field effect transistors (MOSFETs) 56, 58, 60, 62, 64 and 66. Each of the MOSFETs 56 to 66 constitutes each arm of the three-phase inverter circuit. The MOSFET 56 forming the upper arm of the U phase and the MOSFET 62 forming the lower arm of the U phase are connected in series to form a U phase inverter circuit. V-phase inverter circuit and W
The same applies to the phase inverter circuit. The U-phase, V-phase and W-phase inverter circuits are connected in parallel to form a three-phase inverter circuit.

Since the six MOSFETs 56 to 66 have the same configuration, the MOSFET 56 will be described with reference to FIG. The MOSFET 56 has a temperature detecting function and a current detecting function in addition to a normal switching function. Therefore, in addition to the source terminal (S1) on the front surface, the drain terminal (D1) on the back surface, and the gate terminal (G1) on the front surface side, the cathode of the temperature detecting diode is arranged side by side with the gate terminal (G1). Terminal (K1), anode terminal (A1), gate signal source terminal (Ks1),
A current detection terminal (Ss1) is formed. That is,
Five signal terminals are provided on the side surface.

In FIG. 3, the insulating substrate 9 is placed on the heat sink 35.
1, 92 and 93 are mounted. The insulating substrate 91 is made of an insulating plate 94 containing aluminum nitride as a main component and aluminum on the front surface side, and has substantially L-shaped electrode patterns 71a and 74.
And a rectangular electrode pattern 78 and a rectangular electrode pattern 71b made of aluminum on the back surface side.
Electrode patterns 71a, 7 are welded to the insulating plate 94.
4, 71b are joined.

Rectangular electrode patterns 78, 79 and 80 are mounted on the sides of the electrode patterns 74, 75 and 76. Electrode patterns 71a to 73a, electrode pattern 74
To 76 and the electrode patterns 78 to 80 are the heat sink 35.
Is insulated against. That is, as shown in FIG.
The OSFET 56 has the electrode pattern 7 through the solder 59a.
1a, the electrode pattern 7 on the back surface of the insulating substrate 91.
1b is mounted on the heat dissipation plate 35 via the solder 59b. The same applies to the other MOSFETs 58 to 66.

The MOSFET 56 is connected to the rectangular element 78 by wire bonding, and the rectangular element 78 is wire bonded to the first terminal 2 of the first input bus bar 25.
6a. The MOSFET 58 is connected to the rectangular element 79 by wire bonding.
9 is connected to the second terminal 26b by wire bonding. The MOSFET 60 is connected to the rectangular element 80 by wire bonding, and the rectangular element 80 is connected to the third terminal 26c by wire bonding.

The electrode patterns 74, 75 and 76 are respectively formed by wire bonding on the first to third pin groups 51a.
To 51c.

The MOSFET 62 is connected to the electrode pattern 71a by wire bonding.
1a is a first output bus bar 41 by wire bonding
Is connected to the vertical portion 42b. Also MOSFET
Reference numeral 64 is connected to the electrode pattern 72a by wire bonding, and the electrode pattern 72a is connected to the vertical portion 45b of the second output bus bar 44 by wire bonding. Further, the MOSFET 66 is connected to the electrode pattern 73a by wire bonding, and the electrode pattern 73a is wire bonded to the third output bus bar 4a.
7 is connected to the vertical portion 48b.

The MOSFETs 56, 58 and 60 are wire bonded to the first to third pin groups 52a to 52.
c, and the MOSFETs 62, 64 and 66 are wire bonded to the first to third pin groups 51a to 5
It is connected to 1c. (Smoothing Capacitor) As shown in FIGS. 3 and 5, two smoothing capacitors 85 and 86 are housed in the recess 21 of the case body 16. As shown in FIG. 8, the fourth terminal 26d and the fifth terminal 2 of the first input bus bar 25 are
6e are respectively joined to the positive electrode terminal 85a of the first capacitor 85 and the positive electrode terminal 86a of the second capacitor 86 by resistance welding. Similarly, the fourth terminal 31d and the fifth terminal 31e of the second input bus bar 30 are joined to the negative electrode terminal 85b of the first capacitor 85 and the negative electrode terminal 86b of the second capacitor 86 by resistance welding, respectively.

As a result, the positive (higher) side terminal of each phase inverter circuit is connected to the positive terminals 85a and 86a of the first and second smoothing capacitors 85 and 86 and the positive terminal of the battery 150 through the first input bus bar 25. ing. Similarly, the negative (low) side terminal is the second input busbar 3
0 through the first and second smoothing capacitors 85 and 8
6 negative electrode terminals 85b and 86b and the negative electrode of the battery 150. (Control Unit) As shown in FIGS. 1, 5 and 6, the control unit (control circuit) 97 is disposed on the first control circuit board 98a and the second control circuit board 98b. Second
And a control circuit. The first control circuit is MOSFET5
A drive circuit for driving 6 to 66, a drive power supply for driving the drive circuit section, an amplification section for temperature signals and current signals of MOSFETs 56 to 66, and protection based on the detected temperature signals and current signals It is composed of a circuit part. The first to third terminal groups 51a to 51c and the first
The third terminal groups 52a to 52c are soldered to each other through through holes of the control circuit.

On the other hand, the second control circuit is composed of a control unit for controlling three-phase AC, a communication unit with the host ECU 99 and a communication unit with the AC motor. Communication unit is host ECU 9
9 receives the operation command signal from the host ECU 99 and
A diagnostic signal indicating the operating state of the power converter is output to. Also, it receives a rotation signal from the three-phase AC motor 155.

The power converter 10 converts the discharge output of the battery 150 from DC to three-phase AC to drive the three-phase AC motor 155 when starting the gasoline engine of the automobile. On the other hand, during normal traveling, part of the power of the gasoline engine is used to rotate the three-phase AC motor 155 to convert the three-phase AC to DC and charge the battery 150. <Effects of the Embodiment> According to the power converter of the present embodiment, the following various effects can be obtained. (Functional effect) First, smoothing capacitors 85 and 8
The inductance between the MOSFET 6 and the MOSFETs 56 to 66 is significantly reduced (compared to the conventional 40%). This connects the smoothing capacitors 85 and 86 and the MOSFETs 56 to 66 with the first and second input busbars 25 and 30 made of a single member, and the first and second input busbars 25 and 30 and the smoothing capacitor 8
5 and 86 positive electrode terminals 85a and 86a and negative electrode terminal 85
This is because b and 86b are joined by resistance welding.

That is, as apparent from the comparison between FIG. 1 and FIG. 10, the external input busbars 141 and 142 and the external output busbars 146 to 148 in the conventional example are omitted. As a result, the smoothing capacitors 85 and 86
The contact resistance can be reduced while the distance between the MOSFET and the MOSFETs 56 to 66 is shortened. As a result, the surge suppression effect of the smoothing capacitors 85 and 86 is increased,
The breakdown voltage of MOSFETs 56 to 66 can be lowered. The decrease in breakdown voltage lowers the ON resistance of MOSFETs 56 to 66, improves power conversion efficiency, and can be established even when the cooling system is air-cooled.

Second, the first and second input busbars 25 and 30 to the first to third output busbars 41, 44 and 4 are used.
Up to 7, the voltage drop due to contact resistance is small.

The first input busbar 25 has the positive input terminal 28 to the first to third terminals 26a to 26c as a single member, and the second input busbar 30 has the negative input terminal 33 to the first to third terminals 31a. To 31c as a single member, MO
Connection with SFETs 56 to 66 by bonding wires, and first to third output bus bars 41, 44 and 4
7 from the output terminals 43, 46 and 49 of the MOSFET 5
The vertical portions 42b, 45b, and 48b, which are connection terminals to 6 to 66, are formed as a single member, and the MOSFETs 56 to 6
This is because 6 and 6 are connected by a bonding wire.

As a result, unlike the conventional example, the first and second
Input busbars 25 and 30 to first to third output terminals 4
Since there is no screwed portion in the path to 1, 44 and 47, the voltage drop due to contact resistance is small. Further, by eliminating the screw fastening portion, a work space around the screw fastening portion becomes unnecessary, and the bus bars 25, 30, 41, 44 and 4 are provided.
Since 7 can be shortened, the voltage drop due to the conduction resistance of the bus bar becomes small.

As a result, it is possible to secure a sufficient voltage for supplying a current to the three-phase AC motor 155 even with a low voltage (about 14V) such as the auxiliary battery. Further, since there is no screwing portion and the wiring length of the bus bars 25, 30, 41, 44 and 47 is shortened, the positive and negative input terminals 28 and 33 are provided.
To U, V, and W output terminals 43, 46, and 49, the loss in the middle of the wiring is reduced, and the power conversion efficiency is improved. (Effects on Structure and Assembly) First, the size reduction of the power conversion device is achieved. This is the module 10 in the conventional example.
4 is abolished and five bus bars 25, 30, 41, 44 and 47 are embedded in the resin case body 16, and from a different point of view, the contents of the case body 16 (the first wiring portion 2
3 and the second wiring portion 24) to the bus bars 25, 30, 41,
This is because it is used as a wiring space for 44 and 47.
More specifically, by embedding the first and second input busbars 25 and 30 from the first side wall portion to the first wiring portion 23, the inner wall surface of the recess 18 and the first and second input busbars 2 are formed.
It becomes unnecessary to provide a gap for insulation between 5 and 30. As a result, the first side wall 18a and the second side wall 18b
And the distance between the third side wall 18c and the fourth side wall 18d can be narrowed.

Further, smoothing capacitors 85 and 86 and M
This is because the OSFETs 56 to 66 are placed at positions that do not overlap with each other in plan view. More specifically, the MOSFETs 56 to 66 and the control circuit 97 are directly arranged in the first to third terminal groups 51a to 51c and the first to third terminal groups 52a to 52c by arranging them in a region where they do not overlap in a plan view. Can be connected and no signal wire is required. As a result, the position of the connector 53, that is, the height of the power conversion device can be reduced.

Secondly, the weight of the storage case 16 is reduced.
The weight reduction is due to the material being resin. The weight per unit volume of resin is a fraction of that of aluminum. Since the volume of the storage case 16 occupies a considerable portion of the power conversion device, it is significant to reduce the weight per unit volume.

Third, by removing the external input busbars 141 and 142 and the external output busbars 146 to 148, the number of busbars is reduced. As a result, the number of parts is reduced and the weight is reduced.

Fourth, the work of joining the P terminal 28 and the N terminal 33, the smoothing capacitors 85 and 86, the MOSFETs 56 to 66, and the output terminals 43, 46 and 49 is simple and easy. This is because the first and second input bus bars 25 and 30 and the smoothing capacitors 85 and 86 are joined by resistance welding, and the MOSFETs 56 to 66 and the first to third output terminals 41, 44 and 47 are connected by wire bonding. It depends on what you did.

[0073]

As described above, according to the present invention, the high side and the low side of the smoothing capacitor and the high side and the low side of the semiconductor element of the power conversion section are the first and second input bus bars, respectively. The semiconductor element and the AC motor are electrically connected by a plurality of output bus bars. Therefore,
The surge is satisfactorily suppressed by the smoothing capacitor, the voltage drop during power conversion is small, and the increase in inductance and conduction resistance is suppressed as much as possible. As a result, it is possible to obtain a compact and lightweight power conversion device having excellent power conversion efficiency.

[Brief description of drawings]

FIG. 1 is an overall conceptual diagram of a power conversion system including an embodiment (power conversion device) of the present invention.

FIG. 2 is a plan view showing a storage case of the above embodiment.

FIG. 3 is a plan view of the above embodiment.

FIG. 4 is a sectional view taken along line 4-4 of FIG.

FIG. 5 is a perspective view of the above embodiment.

FIG. 6 is an electric circuit diagram of the power converter of the above embodiment.

7 is a sectional view taken along line 7-7 in FIG.

FIG. 8 is an explanatory diagram illustrating joining of input bus bars in the above-described embodiment.

FIG. 9 is an explanatory diagram illustrating an overall arrangement in the above embodiment.

FIG. 10 is an overall conceptual diagram of a conventional example.

FIG. 11 is an explanatory diagram corresponding to FIG. 9 in the conventional example.

FIG. 12 is an explanatory diagram corresponding to FIG. 10 in the conventional example.

[Explanation of symbols]

10: Power Converter 15: Storage Case 21: First Storage 22: Second Storage 25: First Input Busbar 30: Second Input Busbar 41: First Output Busbar 44: Second Output Busbar 47: Third Output Bus bar 55: power conversion units 56, 58, 60, 62, 64,
66: Semiconductor elements 85, 86: Smoothing capacitor 97: Controller 150: DC power supply 155: Three-phase AC motor

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5H007 BB06 CA02 CB02 CB05 CC01                       CC03 FA01 FA13 FA20 HA02                       HA03 HA04

Claims (8)

[Claims] 1. A power conversion device interposed between a direct current power supply and an alternating current motor, for converting direct current into alternating current and converting alternating current into direct current, and including a plurality of semiconductor elements, and direct current and alternating current. A power conversion unit for mutually converting power between the two, a smoothing capacitor for smoothing an output of a DC power supply supplied to each semiconductor element, a control unit for controlling a switching operation of each semiconductor element, and the power conversion A storage case made of resin having a first storage portion for storing a smoothing capacitor, a second storage portion for storing the smoothing capacitor, a positive terminal electrically connected to the high side of the DC power source, and a high level for the smoothing capacitor. A first capacitor terminal that conducts with the terminal, and a plurality of first capacitors that conduct with the high-level terminals of each of the semiconductor elements.
A semiconductor terminal and a single member, the first input bus bar embedded in the housing case, a negative terminal electrically connected to the lower side of the DC power source, and a second capacitor electrically connected to the lower terminal of the smoothing capacitor. A plurality of second terminals that are electrically connected to the terminals and the lower terminals of each of the semiconductor elements.
A semiconductor terminal and a second member that are made of a single member and are embedded in the storage case, a first end portion that is electrically connected to the semiconductor element, and a second end portion that is electrically connected to the AC motor. And a plurality of output bus bars embedded in the storage case. 2. The power conversion device according to claim 1, wherein the first storage portion and the second storage portion of the storage case are arranged in a region that does not overlap in a plan view. 3. The first input bus bar has an elongated shape, and the positive terminal is formed at one end, the first capacitor terminal is formed at one side, and the plurality of first semiconductor terminals are formed at the other side. The power converter according to 1. 4. The second input bus bar has an elongated shape, the negative terminal is formed at one end, the second capacitor terminal is formed at one side, and the plurality of second semiconductor terminals are formed at the other side. The power converter according to 1. 5. The power conversion device according to claim 3, wherein the first input busbar and the second input busbar are arranged insulated from each other in a region overlapping with each other in a plan view. 6. The power conversion device according to claim 1, wherein the plurality of output bus bars are insulated from each other in a region where they do not overlap each other in a plan view. 7. The storage case has a bottom portion and a plurality of side wall portions, and the first input bus bar and the second input bus bar are embedded from the first side wall portion to the bottom portion. Power converter. 8. The power conversion device according to claim 6, wherein the storage case has a bottom portion and a plurality of side wall portions, and the plurality of output bus bars are buried from the second side wall portion to the bottom portion.