JPH1189246A - Three-phase inverter module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-phase inverter module excellent in driving reliability wherein the increase of electric power loss in the module and the increase of heat generation in the module which is caused by the increase of the electric power loss are restrained, and the enlargement of the module size and the increase of manhour for manufacture are unnecessary when electric power is increased. SOLUTION: The respective phase inverter circuits 7U, 7V, 7W constituting a three-phase inverter circuit 3 mounted on a common circuit board are connected with a high potential power source line 91 and a low potential power source line 92 through high potential DC terminals 7a, 7c, 7e and low potential DC terminals 7b, 7d, 7f which are mutually independent. Thereby the increase of electric power loss in a module 3 and the increase of heat generation in the module 3 which is caused by the increase of electric power loss are restrained when electric power is increased, the enlargement of the module 3 and the increase of manhour for manufacture are unnecessary, and a three- phase inverter module 3 excellent in driving reliability can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a three-phase inverter module having a three-phase inverter circuit mounted on a single board.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. Hei 4-26380 discloses an
One of the main electrodes of the high-side power switching element and the low-side power switching element forming the lower arm is connected to form a phase output terminal, and the other main electrodes of the two elements are individually connected. A three-phase inverter circuit (see FIG. 5) having three phase inverter circuits serving as a high-level DC input terminal and a low-level DC input terminal, a single board on which the three-phase inverter circuit is mounted, and disposed on this board And a single high-level DC terminal connected to a high-level end of the external DC power supply through a high-level power supply line (high-level DC bus) and an external DC power supply disposed on the substrate through a low-level power supply line (low-level DC bus) And a single low-level DC terminal connected to the low-level terminal of the inverter, and a high-level DC terminal laid on the board connected to the high-level DC input terminal of the inverter circuit of each phase, and further a low-level DC terminal is connected to each terminal. Phase Invar Three-phase inverter module and a dc connection which connects to the low DC input terminal of the circuit - discloses Le.

FIG. 5 shows a conventional motor control device for controlling a three-phase AC motor 9 by using a three-phase inverter module 3, wherein 1 is a motor controller, 2 is a smoothing capacitor, and 3 is a three-phase motor. Inverter module, 4 is current sensor,
5 is an internal controller, 6 is a main battery, 7a is IGB
A high-side (upper arm) power switching element composed of T71a and diode 72a, and 7b is an IGBT 7
1b and diode 72b (lower side)
7c is an IGBT 71c
And the high side (upper arm) consisting of diode 72c
7d is a low side (lower arm) power switching element composed of an IGBT 71d and a diode 72d, and 7e is a high side (upper arm) composed of an IGBT 71e and a diode 72e. Power switching element, 7f is IGBT 71f and diode
This is a low-side (lower arm) power switching element composed of a gate 72f. Power switching elements 7a, 7
b constitutes a U-phase inverter circuit, power switching elements 7c and 7d constitute a V-phase inverter circuit, and power switching elements 7e and 7f constitute a W-phase inverter circuit. Is composed. 9 is a three-phase AC motor, 11
Is an auxiliary battery, 32 is a high-level DC terminal of the three-phase inverter module 3, 33 is a low-level DC terminal of the three-phase inverter module 3, 331 to 333 are three-phase AC terminals of the three-phase inverter module 3, Reference numeral 91 denotes a high-level power supply line (high-level DC bus), 92 denotes a low-level power supply line (low-level DC bus), and 101 to 106 denote one main electrode of each of the power switching elements 7a to 7f and a high-level DC terminal.
A DC connection line for connecting one of the terminal 32 and the lower DC terminal 33. Reference numerals 107 to 109 denote the other main electrodes of the power switching elements 7a to 7f and the three-phase AC terminals 331 to 333, respectively. AC connection line to be connected.

[0004]

Problems of the above-described conventional three-phase inverter module 3 mounted on a common substrate will be described below. The first problem is that when the power is increased, the size of the module is increased, so that the extension distance of the DC connection lines 101 to 106 is increased, and the amount of current flowing therethrough is increased. Power loss and heat generation increase.

More specifically, these DC connection lines laid on the module are usually formed of thin film conductors or bonding wires formed by printing or baking, and other lines in the three-phase inverter module 3 are used. Is most suitable for the commonization of the manufacturing process, but in order to reduce the resistance value of the DC connection lines 101 to 106, a large number of bonding wires are provided in parallel or the thickness is limited. The width of the thin film conductor needs to be designed wide, which is not easy in terms of process or space. Each DC connection line 10
If the busbars 1 to 106 are replaced with busbars, the resistance can be greatly reduced. However, these busbars are connected to the main electrodes of the power switching elements 71a to 71f and the high-order DC terminal 3a.
In order to fix between the two and the lower DC terminal 33, it is necessary to provide a large number of screw fastening mechanisms on the three-phase inverter module 3, and further, for example, a busbar arrangement space above the three-phase inverter module 3. Therefore, there is a problem that the physical size of the module becomes large. Furthermore, since a plurality of busbars must be newly attached, various problems such as an increase in the number of parts, an increase in the probability of malfunction due to loosening of the fastening screws due to assembly costs, and vibrations have newly arisen. If no screws are used, they are welded or integrated with 32 and 33. However, any of these leads to an increase in cost, and when a bonding wire is used, the cost increases due to an increase in the number of wires.

As a second problem, each of the DC connection lines 101 to 101
If the lengths of the power switching elements 106a are different from each other, the resistance voltage drops of the power switching elements 71a to
There is a problem that the operation timing of the line 71f varies. More specifically, the turn-on and turn-off of the power switching elements 71a to 71f such as IGBTs depend on the magnitude of the voltage between the control electrode and the main electrode emitter, so that the resistance voltage drop varies. Then, the main electrode potentials of the power switching elements 71a to 71f vary, and the turn-on timings of the power switching elements 71a to 71f vary. Such a variation in the turn-on timing has a problem that a short-circuit current flows or an abnormal voltage rise occurs due to the influence of inductance.

The only way to avoid this problem is to lower the resistance of the DC connection lines 101 to 106 in the same manner as described above, but this causes the above-mentioned problem. As a third problem, in high power applications, the high DC terminal 32 and the low DC terminal 33 are fastened to the high power line 91 and the low power line 92, which are low-resistance busbars, with screws. Normally, in a high vibration environment such as for a vehicle, there is a possibility that the screw becomes loose and the motor becomes inoperable. Of course, the power supply lines 91, 92 are connected to these terminals 32, 33 by soldering or the like.
May be connected, but disadvantages such as an increase in man-hours and difficulty in replacing the three-phase inverter module 3 occur.

As a fourth problem, part of the heat generated in the power switching elements 71a to 71f is
Through the power supply line 91 and the low-level power supply line 92, which are usually busbars, and are radiated to the air through the two power supply lines 91 and 92. There is a problem that any one of the power switching elements 71a to 71f is easily overheated by the variation of the thermal resistance.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and suppresses an increase in power loss inside the module and an increase in heat generation inside the module even when the power is increased. It is an object of the present invention to provide a three-phase inverter module that does not require an increase in size or an increase in the number of manufacturing steps and has excellent operation reliability.

[0010]

According to the three-phase inverter module of the first aspect, each of the phase inverter circuits constituting the three-phase inverter circuit mounted on the common board has its own high-order DC power supply. It is connected to the higher power supply line and the lower power supply line through the terminal and the lower DC terminal.

In this way, even if the power is increased, an increase in power loss inside the module and an increase in heat generation inside the module due to the increase are suppressed, and the module is increased in size and the number of manufacturing steps is increased. , And a three-phase inverter module with excellent operation reliability can be realized. Less than,
This will be described in more detail. First, according to this configuration, the high-level DC input terminal and the low-level DC input terminal of each phase inverter circuit are respectively dedicated high-level DC terminal and low-level DC terminal.
The terminal is connected to the terminal via a DC connection line, so that each of the high-order DC terminal and the low-order DC terminal
It can be placed close to the higher DC input terminal and the lower DC input terminal to be connected so as to be closest to the physically and electrically allowable range, and a total of six DC connection lines connecting them. Can be formed as short as possible.

As a result, it is possible to reduce the power loss and heat generation of the DC connection line which is disposed in the module and the resistivity of which is not easily reduced. In addition, the DC connection lines that form the heat transfer resistance between the high power supply line and the low power supply line and the power switching element, which are formed by bus bars and have a large heat capacity and heat dissipation function, are shortened. This is effective for reducing the temperature of the device. Further, since a plurality of bus bars are not newly provided in the module to replace the DC connection line, the module is not increased in size, the number of parts and the mounting cost are not increased, and a high vibration environment is not required. No malfunction occurs due to the loosening of the bus bar fastening screw even underneath.

Second, according to this configuration, the above-described total 6
The DC connection lines can be formed in the shortest possible shape, and the variation in length between the DC connection lines is reduced in principle. As a result, the problem that the resistance voltage drop varies and the operation timing of each power switching element varies can be greatly reduced as compared with the related art.

Third, according to the present configuration, each phase inverter circuit is connected to the high power supply line and the low power supply line through its own high DC terminal and low DC terminal. Even if one of the high- and low-level DC terminals is loosened and one of the phase inverter circuits malfunctions, a problem occurs in the remaining two phase inverter circuits. Nothing. In this case, since the three-phase inverter module normally drives a three-phase AC motor as a load, if such a two-phase inverter circuit is healthy, the three-phase AC motor can be operated in two phases. Thus, it is possible to avoid the problem that the motor stops. On the other hand, in the above-described conventional three-phase inverter module mounted on a common substrate, each phase inverter circuit is configured to be supplied with power through a pair of high-order DC terminals and low-order DC terminals. When one of the terminals became loose, the motor stopped. Of course, even in the three-phase inverter module of this configuration, if two of the DC terminals are loosened, the motor stops. However, the probability that two or more DC terminals are simultaneously loosened two is extremely low. It doesn't have to be a problem.

After all, according to the three-phase inverter module having this configuration, the operation reliability can be improved. According to the second aspect of the present invention, a bus bar is further employed as a power supply line in the first aspect.
In this way, the function and effect can be further improved as described above.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The power switching element is an MO
S, bipolar, SIT, IGBT and the like can be adopted.
The three-phase inverter circuit can have a fourth phase inverter circuit for controlling the neutral current of the star-connected motor.

(Embodiment 1) FIG. 1 shows a three-phase AC motor controller for an electric vehicle using a three-phase inverter module of the present invention. 1 is a motor controller, 2 is a smoothing capacitor, 3 is a three-phase inverter module, 4 is a current sensor, 5 is an internal controller, 6 is a main battery, 7
a is a high-side (upper arm) power switching element comprising an IGBT 71a and a diode 72a; 7b is a low-side (lower arm) power switching element comprising an IGBT 71b and a diode 72b; Is IG
A high-side (upper arm) power switching element composed of a BT 71c and a diode 72c, and 7d is an IGB
A low-side (lower arm) power switching element comprising T71d and diode 72d, 7e is an IGBT 7
1e and the high side (diode 72e)
7f is an IGBT 71f
And lower side composed of a diode 72f (lower arm)
Power switching element. Power switching elements 7a and 7b constitute a U-phase inverter circuit 7U, power switching elements 7c and 7d constitute a V-phase inverter circuit 7V, and power switching element 7U.
e and 7f constitute a W-phase inverter circuit 7W. 8 is a relay circuit, 9 is a three-phase AC motor, 10 is a switch, 11 is an auxiliary battery, 12 is a vehicle electronic control circuit, 32a, 32c and 32e are high-level DC terminals of the three-phase inverter module 3. , 32b, 32d, and 32f are low-level DC terminals of the three-phase inverter module 3,
31 to 333 are three-phase AC terminals of the three-phase inverter module 3, 91 is a higher power supply line (higher DC bus),
92 is a lower power line (lower DC bus), 101 to 10
Reference numeral 6 denotes one main electrode of each of the power switching elements 7a to 7f and the high-order DC terminals 32a, 32c, 32
e and one of the low-level DC terminals 32b, 32d, and 32f, respectively. DC connection lines 107 to 109 are respectively connected to the other one main electrode of each of the power switching elements 7a to 7f and the three-phase AC terminal. It is an AC connection line connecting 331 to 333.

Hereinafter, the basic operation of the apparatus will be briefly described. When the switch 10 is turned on by the vehicle electronic control circuit 12, the internal controller 5 is activated, and the relay circuit 8 is turned on.
Is turned on, power is supplied to the three-phase inverter module 3. The internal controller 5 controls the IGBTs 71a to 71 based on a current signal detected from the current sensor 4 and a signal from the three-phase inverter module 3 or the vehicle electronic control circuit 12.
The gate voltages of f are controlled and intermittently connected in a predetermined order to supply the three-phase AC motor 9 with three-phase AC power. The smoothing capacitor 2 includes a high power supply line 91 and a low power supply line 9
2 to suppress the voltage fluctuation.

The three-phase inverter module 3 of this embodiment
An important feature of the present invention is that each phase inverter circuit 7U, 7V, 7W has a separate DC connection line 101 to 101, although they are integrated on a single substrate as described later.
Reference numeral 106 designates a separate high-order DC terminal 32
a, 32c, 32e and low-order DC terminals 32b, 3
The point is that they are individually connected to 2d and 32f.

FIG. 2 is a schematic plan view of the three-phase inverter module 3, and FIG. 3 is a cross-sectional view taken along line AA of FIG.
The three-phase inverter module 3 has a base material 24 which is formed of a composite material obtained by impregnating a ceramic material such as SiC with aluminum, and forms a common substrate.
On the upper surface of the base member 24, for example, a known green substrate 25, 26, such as a ceramic substrate made of AIN having good thermal conductivity, by known soldering or aluminum brazing or fusion bonding with aluminum contained in the base member 24. 27 are joined. As the base material 24, a metal made of, for example, Cu having excellent heat conductivity can be used. In the case of metal, the green boards 25, 26 mounted on the base material 24,
In order to make the thermal expansion coefficient of 27 close to that of the base member 24, for example, an alloy of Cu and Mo or an alloy of Cu and W may be used.

On the upper surfaces of the insulating substrates 25 to 27, for example, C
u or AI six conductor patterns 28a, 28
b, 28c, 28d, 28e, and 28f are joined by direct joining. Power switching elements 7a to 7f are individually joined onto the conductor patterns 28a to 28f by brazing. On the upper surfaces of the insulating substrates 25 to 27, six conductor patterns 29a, 29b, 29c, 2
9d, 29e and 29f are also joined.

As described above, the power switching element 7a includes the IGBT 71a and the diode 72a, and the IGBT 71a is connected to the IGBT 711 connected in parallel.
a, 712a, 713a, and a diode 72a
Are diodes 721a, 722a, 7 connected in parallel
23a. Similarly, the power switching element 7b
Consists of an IGBT 71b and a diode 72b,
The IGBT 71b is an IGBT 71lcb connected in parallel.
712b, 713b, and the diode 72b is connected in parallel to the diodes 721b, 722b, 723b.
Consists of The power switching element 7c is an IGBT 7
1c and a diode 72c, but the IGBT 71c
Are the IGBTs 71lc, 712c, 71 connected in parallel.
3c, and the diode 72c includes diodes 721c, 722c, and 723c connected in parallel. Similarly, the power switching element 7d includes an IGBT 71d and a diode 72d. The IGBT 71d includes IGBTs 71ld, 712d, and 713d connected in parallel, and the diode 72d includes diodes 721d, 722d, and 723d connected in parallel. . The power switching element 7e includes an IGBT 71e and a diode 72.
e, the IGBT 71e is connected in parallel with the I
GBTs 71le, 712e and 713e, and the diode 72e is connected in parallel to the diodes 721e and 721e.
22e and 723e. Similarly, the power switching element 7f includes an IGBT 71f and a diode 72f, and the IGBT 71f is connected in parallel to the IGBT 71f.
71lf, 712f, 713f, and the diode 7
2f is diodes 721f, 722 connected in parallel.
f, 723f.

An insulating case 3 is provided on the periphery of the base member 24.
1 are adhered, and the upper DC terminal 32a, 32c, 32e and the lower DC terminal
The terminals 32b, 32d, 32f and the three-phase AC terminals 331 to 333 are fixed by insert molding. Although not shown, these high-order DC terminals 32a,
32c and 32e, and the lower DC terminals 32b and 32
The positive and negative terminals of the smoothing capacitor 2 are fixed with bus bars between the terminals d and 32f.
The three-phase AC motor 9 is connected to .about.333.

High-order DC terminals 32a, 32c, 32
e is the semiconductor elements 71la, 712a, 713a, 72
1a, 722a, 723a, 71lc, 712c, 71
3c, 721c, 722c, 723c, 71le, 71
2e, 713e, 721e, 722e, and 723e are connected to the conductor patterns 28a, 28o, and 28e, which are electrically connected, by bonding wires.

The low-order DC terminals 32b, 32d, 32
f denotes the semiconductor elements 71lb, 712b, 713b, 72
1b, 722b, 723b, 71ld, 712d, 71
3d, 721d, 722d, 723d, 71lf, 71
Conductor pattern 29b conductively connected to bonding wires 2f, 713f, 721f, 722f, and 723f;
29d and 29f are connected by bonding wires. The three-phase AC terminals 331 to 333 are conductor patterns.
28b, 28d, 28f and the semiconductor elements 71la, 7
12a, 713a, 721a, 722a, 723a, 7
1lc, 712c, 713c, 721c, 722c, 7
23c, 71le, 712e, 713e, 721e, 7
The conductor patterns 29a, 29c, and 29e, which are electrically connected to the conductor patterns 22e and 723e by bonding wires, are connected by bonding wires.

Semiconductor elements 71la to 713a, 71lb
To 713b, 71lc to 713o, 711d to 713
d, 71le to 713e, 71lf to 713f, and conductor portions 36a, 36 insert-molded in the insulating case 31.
b, 36c, 36d, 36e, 36f are bonding wires 37a, 37b, 37c, 37d, 37e, 37
f, and the conductors 36a to 36f are soldered to the control circuit 5 disposed immediately above.

By using the three-phase inverter module 3 of this embodiment, the following effects can be obtained. (A) Each phase inverter circuit 7U, 7 constituting a three-phase inverter circuit mounted on a base material 24 as a common substrate
V and 7W have their own high-order DC terminals 7a,
7c, 7e and the lower DC terminals 7b, 7d, 7f are connected to a higher power line 91 and a lower power line 92 which are busbars.

By doing so, the high-order DC terminal 7
a, 7c, 7e and lower DC terminals 7b, 7d, 7
f denotes each phase inverter circuit 7U, 7U to be connected so as to be closest to the physically and electrically allowable range.
V and 7W can be arranged close to the high DC input terminal and the low DC input terminal. As a result, a total of six DC connection lines 101 to 106 consisting of conductor patterns or bonding wires connecting them can be provided. It can be formed as short as possible.

As a result, it is possible to reduce the power loss and the heat generation of the DC connection lines 101 to 106 which are disposed in the module 3 and are not easily reduced in resistivity. In addition, bus bar
The DC connection lines 101 to 106 which form heat transfer resistances between the high power supply lines 91 and the low power supply lines 92 and the power switching elements 7a to 7f, which have a large heat capacity and a heat dissipation function, are shortened. This is effective for reducing the temperature of the power switching elements 7a to 7f. Further, since a plurality of busbars are not newly provided in the module 3 to replace the DC connection lines 101 to 106,
There is no increase in the size of the module 3, the number of parts and the cost of assembling, and no malfunction occurs even in a high vibration environment due to loosening of the bus bar fastening screws.

(B) Six DC connection lines 10 in total
1 to 106 can be formed in the shortest possible shape, and the variation in length between the DC connection lines 101 to 106 is reduced in principle. As a result, the problem that the operation timings of the IGBTs 71a to 71f vary due to the variation in the resistance voltage drop can be significantly reduced as compared with the related art.

(C) Inverter circuits 7U, 7V, 7 for each phase
W is a high-level DC terminal 7a, 7c, 7e dedicated to oneself.
And the lower DC terminals 7b, 7d, 7f are connected to the higher power line 91 and the lower power line 92, so that the higher DC terminals 7a, 7c, 7e and the lower DC terminals 7b, 7d, 7f should be used. One of the connection parts (usually a screw) is loosened and each phase inverter circuit 7
Even if one of U, 7V, and 7W malfunctions, no problem occurs in the remaining two phase inverter circuits, and the three-phase AC motor 9 can be operated in two phases. Thus, it is possible to avoid the problem that the motor stops.

(D) High-order DC terminals 7a, 7c, 7
e and the low-level DC terminals 7b, 7d, 7f are connected to the DC connection lines 101-106
And the self-inductance and resistance are reduced by the extent that the variation in the length of the DC connection lines 101 to 106 is reduced, and the surge voltage superimposed on the higher power supply line 91 and the lower power supply line 92 is correspondingly reduced. And the withstand voltage of each of the power switching elements 7a to 7f can be reduced accordingly. Further, the snubber circuit for absorbing the surge voltage can be reduced in size or omitted.

(Embodiment 2) Another embodiment will be described with reference to FIG. This embodiment is different from the first embodiment shown in FIG.
In the three-phase inverter module 3, a connecting wire 101 connecting between the high-order DC terminals 7a, 7c and 7e and a connecting wire 102 connecting between the low-order DC terminals 7b, 7d and 7f are added. is there. With this configuration, the circuit can be stably operated even when the screws of a plurality of terminals among the high-order DC terminals 7a, 7c, 7e and the low-order DC terminals 7b, 7d, 7f are loosened. The following effects can be obtained.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of a motor control device employing a three-phase inverter module of the present invention.

FIG. 2 is a plan view of the three-phase inverter module 3 shown in FIG.

FIG. 3 is a vertical sectional view of the three-phase inverter module 3 shown in FIG.

FIG. 4 is a circuit diagram illustrating a motor control device according to a second embodiment.

FIG. 5 is a circuit diagram showing a motor control device employing a conventional three-phase inverter module.

[Explanation of symbols]

1 is a motor controller, 2 is a smoothing capacitor, 3 is a three-phase inverter module, 4 is a current sensor, 5 is an internal controller, 6 is a main battery, 7a to 7f are power switching elements, 7U, 7V, 7W. Is a phase inverter circuit, 9 is a three-phase AC motor, 32a, 32c and 32e are high-order DC terminals of the three-phase inverter module 3, 32
b, 32d and 32f are low-level DC terminals of the three-phase inverter module 3, 91 is a high-level power supply line, 92 is a low-level power supply line, and 101 to 106 are DC connection lines.

Claims (2)

[Claims] 1. One of the main electrodes of a high-side power switching element forming an upper arm and a low-side power switching element forming a lower arm is connected to form a phase output terminal. A three-phase inverter circuit having three phase inverter circuits each having a high DC input terminal and a low DC input terminal between the other main electrodes, a single board on which the three-phase inverter circuit is mounted, and the board A high-level DC terminal connected to a high-level end of an external DC power supply through a high-level power supply line; and a low-level power supply line connected to a low-level end of the external DC power supply through a low-level power supply line A low-level DC terminal, which is laid on the substrate, connects the high-level DC terminal to the high-level DC input terminal of each phase inverter circuit, and connects the low-level DC terminal to each phase inverter. Ta times A DC connection line connected to the lower DC input of the circuit, wherein the higher DC terminals are separately connected to the higher DC inputs of the three phase inverter circuits. Three are arranged in close proximity,
3. The three-phase inverter module according to claim 3, wherein said three low-level DC terminals are separately disposed close to said low-level DC input terminals of said three phase inverter circuits. 2. The three-phase inverter module according to claim 1, wherein said higher power supply line and said lower power supply line are busbars.