JP2003168777A - Inverter control module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inverter control module capable of effectively preventing destruction of a switching element and are discharge between two power lines due to surge voltage application. <P>SOLUTION: The inverter control module is composed of a ceramic substrate 2, the two power lines 3a and 3b arranged facing both main surfaces of it for which the direction of a flowing current is opposite, three output lines 4a-4c arranged on one main surface of the ceramic substrate 2, the switching element 5 mounted on the power line 3a and the respective output lines 4a-4c, a control line 9 arranged on the other main surface corresponding to the switching element 5, a first connection means 6 connecting the switching element 5 on the power line 3a to the respective output lines 4a-4c, a second connection means 7 connecting the switching elements 5 mounted on the respective output lines 4a-4c to the power line 3b, and a third connection means 8 connecting the switching element 5 through the ceramic substrate 2 to the control line 9. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter control module for controlling a three-phase motor or the like. 2. Description of the Related Art Conventionally, an inverter control module for controlling a three-phase motor or the like is generally shown in a plan view of FIG.
5 and two power lines 33 to which DC power is supplied to one main surface of the ceramic substrate 32.
a, 33b and three output lines 34a, 34b, 34c for outputting a three-phase AC power supply, a power circuit 33a and a ceramic circuit board 31 on which the output lines 34a, 34b, 34c are formed, and one power line 33a. And a plurality of switching elements 35 mounted on each output line 34a, 34b, 34c, each switching element 35 mounted on one power line 33a and each output line 34a, 34b, 34c.
(c) first connection means comprising a thin metal wire for electrically connecting the first and second wires to each other
36, a second connecting means 37 composed of a thin metal wire for electrically connecting each switching element 35 mounted on each output line 34a, 34b, 34c to the other power line 33b; And a third connection means 38 made of a thin metal wire for electrically connecting the control board to the control board. In such an inverter control module, two power lines 33a and 33b are used as an external power supply, and an output line 34 is used.
a, 34b and 34c are supplied to a three-phase motor or the like by supplying a DC power of 20 A or more between the two power lines 33a and 33b from an external power source, and repeatedly turning on and off each switching element 35 with a slight shift. Thus, three-phase AC power is supplied to the three-phase motor and the like via the output lines 34a, 34b, and 34c. The switching element 35 is an IGB
T (Insulated Gate Bipolar Transistor) and the like are generally used. A ceramic circuit board 31 used for the inverter control module has a metallized metal layer adhered in a predetermined pattern on the surface of a ceramic substrate 32 which is generally made of an aluminum oxide sintered body. Power line 33a, 33b and output line 34
It is formed by brazing a metal circuit board made of copper or the like to become a, 34b, and 34c via a brazing material such as silver brazing. More specifically, a raw material powder such as aluminum oxide, silicon oxide, magnesium oxide and calcium oxide is mixed with an appropriate organic binder, plasticizer, solvent and the like to form a slurry, which is then mixed with a conventionally known doctor. A plurality of ceramic green sheets are obtained by using a tape forming technique such as a blade method or a calendar roll method, and then an appropriate organic binder / solvent for a high melting point metal powder such as tungsten or molybdenum is placed on the ceramic green sheets. The metal paste obtained by addition and mixing is printed and applied in a predetermined pattern by employing a printing technique such as a screen printing method,
Next, the ceramic green sheets on which the metal pastes are printed and applied in a predetermined pattern are vertically stacked as necessary, and fired at about 1600 ° C. in a reducing atmosphere to fire the ceramic green sheets and the metal pastes. Forming a ceramic substrate 32 made of an aluminum oxide sintered body having a metallized metal layer
Finally, power lines 33a and 33b and output lines 34 are formed on the metallized metal layer adhered to the ceramic substrate 32.
a, 34b, 34c and a metal circuit board such as copper which becomes the control line 39 are placed with a brazing material such as silver brazing therebetween.
It is manufactured by heating this to about 900 ° C. in a reducing atmosphere to melt the brazing material, and joining the metallized metal layer and the metal circuit board with the molten brazing material. However, in this conventional inverter control module, the two power lines 33a and 33b have inductance, and
A DC power supply of 20 A or more is supplied between the power lines 33a and 33b, and the on / off of each switching element 35 is slightly shifted so that a three-phase AC power supply is supplied to a three-phase motor or the like via output lines 34a, 34b and 34c. When the power is supplied, a surge voltage higher than the rated voltage is generated when the switching element 35 is turned on and off due to the inductance of the power lines 33a and 33b. As a result, an overvoltage is applied to the switching element 35 by the surge voltage, element
There is a disadvantage that the inverter control module cannot be operated stably and reliably by destroying 35. Therefore, in order to solve the above-mentioned disadvantage, two power lines 33a and 33b are arranged close to each other, and the direction of the current flowing through each of the power lines 33a and 33b is reversed so that the two power lines 33a and 33b are connected to each other. It is conceivable that a mutual inductance is generated and the inductance of the two power lines 33a and 33b is reduced by the mutual inductance. However, the two power lines 33a,
When the power line 33b is arranged in proximity, the power lines 33a, 33
b, a very large current of 20 A or more flows and a voltage of 600 V or more is applied.
Discharge occurs between a and 33b, causing a short circuit in the ceramic circuit board 31 and impairing the operation reliability of the inverter control module. Furthermore, the third connecting means 38 becomes very long and crosses another line, so that there is a danger that the third connecting means 38 may come into contact with other line patterns and the like, and the reliability is impaired. I will. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and has as its object to effectively prevent destruction of a switching element and discharge between two power lines due to application of a surge voltage, thereby achieving a small and stable power supply. An object of the present invention is to provide an inverter control module capable of reliably converting a DC power supply to a three-phase AC power supply for a long period of time. [0012] An inverter control module according to the present invention comprises a ceramic substrate and two power lines arranged opposite to each other on both main surfaces of the ceramic substrate and having flowing currents in opposite directions. Three output lines arranged on one main surface of the ceramic substrate, a plurality of switching elements mounted on the power line and each output line formed on one main surface of the ceramic substrate, A plurality of control lines arranged on the other main surface corresponding to each of the switching elements, first connection means for connecting the switching elements on the power line to the respective output lines, and the respective output lines The switching element mounted thereon is connected to the power line formed on the other main surface of the ceramic substrate. And second connection means for connecting the switching element to the control line through the ceramic substrate. According to the inverter control module of the present invention, the two power lines are opposed to each other with the ceramic substrate interposed therebetween, and the direction of the current flowing through each power line is reversed. Mutual inductance can be efficiently generated between the lines, and the mutual inductance can greatly reduce the inductance of the two power lines, thereby supplying a DC power of 20 A or more between the two power lines, and When three-phase AC power is supplied to a three-phase motor or the like from the output line by shifting the on / off of the switching element little by little, the rated current due to the inductance of the two power lines when the switching element is turned on / off No higher surge voltage occurs,
As a result, it is possible to effectively prevent the switching element from being applied with an overvoltage and to destroy the switching element, and to operate the inverter control module stably and reliably. At the same time, since the two power lines have a ceramic substrate having excellent insulation therebetween, even if a very large current of 20 A or more is applied to the power lines and a voltage of 600 V or more is applied. Therefore, a short circuit does not occur in the ceramic circuit board due to the occurrence of a discharge between the power lines, whereby the operation of the inverter control module can be made highly reliable. Furthermore, the third connection means for penetrating the ceramic substrate and connecting the switching element to the control line arranges the control lines near the corresponding switching elements so as not to intersect with the other lines. The wire bonding length as the connection means 3 can be minimized, contact with other line patterns and the like can be prevented, and the reliability of the module can be further improved. Next, the present invention will be described in detail with reference to an embodiment shown in the accompanying drawings. FIG. 1, FIG. 2 and FIG. 3 are a plan view on the front side, a plan view on the back side, and a sectional view showing an embodiment of the inverter control module of the present invention. In the inverter control module of the present invention, two power lines 3a and 3b are arranged on both main surfaces of the ceramic substrate 2 so as to face each other, and three output lines 4a, 4b and 4c and a power line 3a and a power line are provided on one main surface. A plurality of control lines 9 arranged on the other main surface of the ceramic substrate 2 corresponding to the plurality of switching elements 5 mounted on the line 3a and the output lines 4a, 4b, 4c, respectively.
And a switching element 5. The switching element 5 is mounted on the power lines 3 a and the output lines 4 a, 4 b, 4 c formed on one main surface of the ceramic substrate 2. Then, the switching element 5 on the power line 3a is connected to each of the output lines 4a, 4b, 4c via the first connection means 6, and the switching element 5 mounted on each of the output lines 4a, 4b, 4c is connected. The second connection means 7 is connected to the power line 3b formed on the other main surface of the ceramic substrate 2.
And the switching elements 5 are connected to the corresponding control lines 9 through the through-holes 10, here, through-holes formed in the ceramic substrate 2, through the third connection means 8. ing. Ceramic substrate 2 of ceramic circuit substrate 1
Are power lines 3a and 3b and output lines 4a and 4
b, 4c, and a supporting member for supporting the switching element 5 mounted on the power line 3a and the output lines 4a, 4b, 4c, and includes a silicon nitride sintered body, an aluminum nitride sintered body, and a silicon carbide sintered body. It is formed of a ceramic insulator such as a sintered body or an aluminum oxide sintered body. If the ceramic substrate 2 is made of, for example, a silicon nitride sintered body, an appropriate organic binder, a plasticizer, and a solvent are added to a raw material powder such as silicon nitride, aluminum oxide, magnesium oxide, and yttrium oxide. A ceramic green sheet (ceramic green sheet) is obtained by mixing to form a slurry and using the slurry by a conventionally known doctor blade method or calender roll method.
Then, these ceramic green sheets are subjected to an appropriate punching process to form a predetermined shape, and if necessary, a plurality of sheets are laminated to form a molded body. Thereafter, the green body is subjected to a non-oxidizing atmosphere such as a nitrogen atmosphere. It is manufactured by firing at a high temperature of 1600 to 2000 ° C. in the inside. The through portion 10 through which the third connection means 8 passes is provided.
Is formed at the same time as the ceramic substrate 2 by forming a through-hole serving as the penetrating portion 10 by punching when manufacturing the ceramic substrate 2. Alternatively, after the ceramic substrate 2 is manufactured, the through portion 10 may be formed in the ceramic substrate 2 by a method such as laser processing or cutting. In the ceramic circuit board 1, the ceramic substrate 2 is made of a ceramic insulator having a heat transfer coefficient of 60 W / m · K or more, such as a silicon nitride sintered body, an aluminum nitride sintered body, or a silicon carbide sintered body. When the switching element 5 is formed, when the switching element 5 generates a large amount of heat during operation, the heat is efficiently absorbed by the ceramic substrate 2 and satisfactorily released to the atmosphere to make the switching element 5 always at an appropriate temperature. The switching element 5 can always be operated stably and normally. Therefore, the ceramic substrate 2 is preferably formed of a ceramic insulator having a heat transfer coefficient of 60 W / m · K or more, such as a silicon nitride sintered body, an aluminum nitride sintered body, or a silicon carbide sintered body. . The ceramic substrate 2 has one power line 3a and three output lines 4a, 4b, 4
On the other main surface, one power line 3b and a plurality of control lines 9 are brazed and attached via an adhesive such as an active metal brazing material. The power line 3a is for supplying a DC power supplied from an external power supply to the switching element 5, and the output lines 4a, 4b, 4c are three-phase converted by turning on / off the switching element 5. The AC power is supplied to an external three-phase motor or the like, and the control line 9 is used to control ON / OFF of each switching element 5. The two power lines 3a, 3b, the three output lines 4a, 4b, 4c and the plurality of control lines 9 are made of a metal material such as copper or aluminum, and are made of an ingot of copper or aluminum. For example, a well-known metal working method such as a rolling method or a punching method is applied to the substrate to produce a predetermined pattern shape having a thickness of, for example, 500 μm. The power line 3a and the output line 4
In the case where the penetrating part 10 through which the third connection means 8 passes is formed in a, 4b and 4c, the power line 3a and the output lines 4a and 4c
It is formed simultaneously with the production of b and 4c. Further, the adhesion of the two power lines 3a, 3b, the three output lines 4a, 4b, 4c and the plurality of control lines 9 to the ceramic substrate 2 is performed, for example, by using a silver brazing material (silver: 72 weight%). %, Copper: 28% by weight) and aluminum brazing material (aluminum: 88% by weight, silicon: 12%)
% By weight) of an active brazing material in which at least one of titanium, tungsten, hafnium and / or a hydride thereof is added in an amount of 2 to 5% by weight. The power lines 3a, 3b, the output lines 4a, 4b, 4c and the plurality of control lines 9 are placed with the active metal brazing material interposed therebetween, and then these are placed in a vacuum or in a neutral or reducing atmosphere. Predetermined temperature (about 900 for silver brazing material)
C., about 600.degree. C. for an aluminum brazing material) to melt the active metal brazing material, and to form the front and back surfaces of the ceramic substrate 2, the power lines 3a, 3b, the output lines 4a, 4b, 4c and the plural lines. This is performed by joining the control line 9. The power lines 3a, 3b, the output lines 4a, 4b, 4c and the plurality of control lines 9
If this is made of oxygen-free copper, the oxygen-free copper will have good wettability with the active metal brazing material without being oxidized by the oxygen present in the copper surface during brazing. ,
Bonding to the ceramic substrate 2 via the active metal brazing material becomes strong. Therefore, it is preferable that the power lines 3a, 3b, the output lines 4a, 4b, 4c and the plurality of control lines 9 are formed of oxygen-free copper. Further, the power lines 3a, 3b, the output lines 4a, 4b, 4c and the plurality of control lines 9 have good conductivity made of nickel on their surfaces, and have good corrosion resistance and good wettability to brazing materials. If the metal is applied by plating, the power line 3a, 3b, the output lines 4a, 4b, 4c and the plurality of control lines 9 can be effectively prevented from being oxidized and corroded.
The switching element 5, an external power supply, an external three-phase motor, and the like can be extremely firmly connected to the a, 3b and the output lines 4a, 4b, 4c via a brazing material such as solder.
Therefore, the power lines 3a and 3b and the output line 4
Preferably, the control lines 9a, 4b, 4c and the plurality of control lines 9 are coated with a metal made of nickel and having good conductivity, good corrosion resistance and good wettability to a brazing material by plating. . The ceramic circuit board 1 also has a plurality of switching elements 5 mounted on a power line 3a and output lines 4a, 4b, 4c arranged on one main surface of the ceramic substrate 2, and a power line. The switching element 5 mounted on 3a is a first element made of a wire or the like.
Output lines 4a, 4b, 4c via connection means 6 of
The switching element 5 mounted on the output lines 4a, 4b, 4c is connected to a second connecting means 7 made of a wire or the like.
And all the switching elements 5 are connected to the power line 3b disposed on the other main surface of the ceramic substrate 2 through the penetrating portion 10 by a third connection means such as a wire. 9 are electrically connected to each other. The switching element 5 is an IGBT (Insula
An element such as a ted Gate Bipolar Transistor) is used.
Has a function of converting the DC power supplied from the power lines 3a and 3b into a three-phase AC power and supplying the three-phase AC power to the output lines 4a, 4b and 4c. The first connecting means 6, the second connecting means 7, and the third joining means 8 are made of a thin metal wire (wire) having a diameter of, for example, 300 μm and made of aluminum or an aluminum-silicon alloy. By using a connection method such as a well-known ultrasonic connection method, the switching element 5 mounted on the power line 3a and the output lines 4a, 4
b, 4c, the switching element 5 mounted on the output lines 4a, 4b, 4c and the power line 3b formed on the other main surface of the ceramic substrate 2, and all the switching elements 5 are connected to the control line 9. The ceramic substrate 2 is penetrated and joined by the third connection means 8 through the penetrating portion 10. In the inverter control module of the present invention, the two power lines 3a and 3b are opposed to each other with the ceramic substrate 2 interposed therebetween, and
It is important to reverse the direction of the current flowing through a and 3b. As described above, the two power lines 3a, 3b
Are placed opposite to each other with the ceramic substrate 2 interposed therebetween, and the direction of the current flowing through the power lines 3a and 3b is reversed, so that mutual inductance is efficiently generated between the two power lines 3a and 3b. Due to the mutual inductance, the inductance of each of the two power lines 3a and 3b can be greatly reduced, and as a result, 20 A is applied between the two power lines 3a and 3b.
The above-mentioned DC power is supplied, and the on / off of each switching element 5 is slightly shifted so that the output lines 4a, 4
When a three-phase AC power is supplied from b and 4c to a three-phase motor or the like, a surge voltage higher than the rated voltage occurs due to the inductance of the two power lines 3a and 3b when the switching element 5 is turned on and off. Therefore, it is possible to effectively prevent the switching element 5 from being damaged due to an overvoltage applied to the switching element 5, and to operate the inverter control module stably and reliably. At the same time, the two power lines 3a, 3a
In the case b, since the ceramic substrate 2 having excellent insulating properties is interposed therebetween, even if a very large current of 20 A or more is applied to the power lines 3a and 3b to apply a voltage of 600 V or more, the power lines 3a and 3b There is no occurrence of a short circuit in the ceramic circuit board 1 due to the occurrence of a discharge during this period, whereby the operation of the inverter control module can be made highly reliable. The thickness of the ceramic substrate 2 is 2 m.
If it exceeds m, it is difficult to efficiently generate mutual inductance between the two power lines 3a and 3b, and if it is less than 0.2 mm, the mechanical strength of the ceramic substrate 2 deteriorates and the reliability as an inverter control module is reduced. There is a risk of lowering. Therefore, it is preferable that the thickness of the ceramic substrate 2 be in the range of 0.2 mm to 2 mm. The dielectric strength of the ceramic substrate 2 is
When the thickness is less than 10 kV / mm, when the thickness of the ceramic substrate 2 becomes as thin as, for example, 0.2 mm, a discharge occurs between the power lines 3a and 3b, and there is a risk that a short circuit occurs in the ceramic circuit substrate 1. There is. Therefore, the withstand voltage of the ceramic substrate 2 is preferably set to 10 kV / mm or more. The control line 9 is made as short as possible from the corresponding switching element 5, so that the third connection means 8 does not come into contact with other wiring parts, thereby achieving high reliability. It is possible. Further, it is desirable that the control line 9 is installed at a distance of 0.5 mm or more from another line on which the switching element 5 is mounted. Since the discharge between lines can be prevented by separating by 0.5 mm or more, malfunction of the inverter control module can be prevented. In addition, the connection between the switching element 5 and the control line 9 is performed by the third connection means 8 through the through portion 10 formed in the ceramic substrate 2. As a result, it does not intersect with the other connecting means 6 and 7,
The wire or the like of the third connection means 8 may fall down due to vibration due to the use environment during wire bonding or thereafter, and the other connection means 6.
7 and the power line 3 and the output line 4. As a result, it is possible to provide an inverter control module having high reliability for a long time. Thus, according to the inverter control module described above, the two power lines 3a and 3b are connected to an external power supply, and the output lines 4a, 4b and 4c are connected to a three-phase motor or the like. 20 between 3a and 3b
A is supplied from the output lines 4a, 4b, 4c by supplying a DC power of A or more and repeating the on / off of each switching element 5 while gradually shifting it.
A phase AC power supply is derived and thereby functions as an inverter control module. Note that the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the gist of the present invention. For example, in the example of the above embodiment, the third connection means 8 is directly connected to the control line 9 through the through portion 10 formed as a through hole, and the conductor connected to the control line 9 is connected to this through hole. By disposing the through portion 10 as a through conductor, the third connection means 8 made of a wire or the like may be connected to the surface of the through conductor on one main surface side of the ceramic substrate 2. This penetration
The through conductor as 10 is exposed on one main surface side of the ceramic substrate 2, but is electrically insulated from lines other than the control line 9. The through conductor at this time is arranged in the through hole, and when a metal pillar connected to the control line 9 with a brazing material or the like or the ceramic substrate 2 is manufactured, a paste made of a conductive metal is embedded in the through hole. It is preferable to use a material which is formed by firing simultaneously with the ceramic substrate 2 and is connected to the control line 9 by a brazing material when the control line 9 is attached to the ceramic substrate 2.
Furthermore, power lines 3a,
3b, the output lines 4a, 4b, 4c and the members made of the same material as the plurality of control lines 9 may be connected via a brazing material to form a through conductor. Further, these through conductors are preferably coated with a metal such that a wire or the like serving as the third connection means 8 is satisfactorily connected to the exposed surface by plating. According to the inverter control module of the present invention, the two power lines are arranged to face each other with the ceramic substrate interposed therebetween, and the direction of the current flowing through each power line is reversed. In addition, the mutual inductance can be efficiently generated between the two power lines, and the mutual inductance can greatly reduce the inductance of the two power lines. Supply and 2 when each switching element is turned on and off.
A surge voltage higher than the rated current does not occur due to the inductance of the power line, and as a result, an overvoltage is applied to the switching element, and the switching element is effectively prevented from being destroyed and the inverter control module is prevented from being damaged. It can be operated stably and reliably. At the same time, since the two power lines have a ceramic substrate having excellent insulation therebetween, even if a very large current of 20 A or more is applied to the power lines and a voltage of 600 V or more is applied. In addition, a discharge does not occur between the power lines, and a short circuit does not occur in the ceramic circuit board, whereby the operation of the inverter control module can be made highly reliable. Further, the distance between the control line and the corresponding switching element is made as small as possible, so that the third connection means for penetrating the ceramic substrate and connecting the switching element to the control line makes contact with other wiring parts. And high reliability can be achieved. As described above, according to the present invention, destruction of a switching element due to application of a surge voltage and discharge between two power lines are effectively prevented, and a small and stable DC power supply can be reliably used as a three-phase AC power supply. And an inverter control module capable of performing conversion over a long period of time.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front plan view showing an example of an embodiment of an inverter control module according to the present invention. FIG. 2 is a plan view on the back side showing an example of the embodiment of the inverter control module of the present invention. FIG. 3 is a sectional view of the inverter control module shown in FIG. 1; FIG. 4 is a plan view of a conventional inverter control module. 5 is a sectional view of the inverter control module shown in FIG. [Description of Signs] 1 ... Ceramic circuit board 2 ... Ceramic boards 3a, 3b ... Power lines 4a, 4b, 4c ... Output line 5 ... Switching element 6 ... First connection means 7 ... Second connection means 8 ... · Third connection means 9 ······· Control line 10 ·············

Claims (1)

Claims: 1. A ceramic substrate, wherein the ceramic substrate is disposed opposite to both main surfaces of the ceramic substrate, and the directions of flowing currents are opposite to each other.
Power lines, three output lines disposed on one main surface of the ceramic substrate, and a plurality of switching lines mounted on the power lines and the output lines formed on the one main surface. An element, a plurality of control lines arranged on the other main surface corresponding to each of the switching elements, first connection means for connecting the switching element on the power line to each of the output lines, and Second connection means for connecting the switching element mounted on an output line to the power line formed on the other main surface of the ceramic substrate, and the control line passing through the ceramic substrate through the switching element. And a third connection means for connecting to the inverter control module.