JPH10309073A - Power converter and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the inductance existing in a wiring conductor, in a power converter using a semiconductor switching element. SOLUTION: This power converter is equipped with a first conductor 1 and a second conductor 2 to connect circuit constituent parts, and the second conductor 2 is arranged closely at a certain distance at one part or the whole section of the first conductor 1 by a spacer, so that the section which lies at one part at least upon the plane of projection in the direction of thickness of the first conductor 1 and the section which does not lie upon it may be made, and further one point at least of the second conductor 2 is electrically connected to the first conductor 1 by a conductive screw 5. Hereby, a power converter where the wiring inductance of the first conductor 1 is reduced to lighten the surge voltage at turn off of a semiconductor switching element and also the loss is low, by generating an induced current in the second conductor 2 and negating the magnetic flux of the first conductor 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter using a semiconductor switching element, and more particularly to a wiring structure for reducing wiring inductance in a power converter circuit.

[0002]

2. Description of the Related Art In a conventional power converter, for example,
As shown in JP-289346A, the wiring inductance is reduced by bringing the wiring conductor close to the input / output current of the capacitor terminal and the like, that is, the current having the same absolute value and flowing in the opposite direction. FIG. 26 shows this state. By arranging the respective wiring conductors at the plus side terminal and the minus side terminal of the capacitor close to each other, a current flows in the opposite direction between the respective wiring conductors, and the effect of canceling out the mutual magnetic flux is used.

[0003]

In the power converter as described above, a current having the same absolute value and flowing in the opposite direction is indispensable in the vicinity of the wiring conductor. In order to enhance the effect of reducing the number of wires, the distance between the wiring conductors must be reduced.
However, the majority of cases have a single current direction for the following reasons. For example,
The 6-inch GTO (Gate Turn-Off) thyristor (hereinafter abbreviated as GTO) that has begun to appear on the market has an electrical rating of 6 kV and 6 kA.
That is all. For this reason, an insulation distance larger than that of a conventional 4-inch GTO or the like is required. Also, with the increase in the capacity of the converter, a capacitor is required to have a higher withstand voltage, and the capacity of the capacitor is increased in proportion to approximately the square of the rated voltage. Therefore, the distance between the components is inevitably increased. In addition, due to the increase in the size of circuit components, restrictions on the wiring mounting area have also increased. As described above, in the large-capacity converter, although the absolute value is partially the same and a current in the opposite direction is obtained, the effect of reducing the wiring inductance decreases because the insulation distance increases.
Also, in most cases, there is no current in the opposite direction near the wiring conductor connecting the components. For this reason, there is a problem associated with the following wiring inductance in an actual power converter.

FIG. 22 shows an example of the configuration of a power converter. A converter 102 converts an AC voltage of an AC power supply 101 into a DC voltage, a smoothing capacitor 103 for smoothing an output voltage of the converter 102, and The inverter 104 includes an inverter 104 that converts the voltage into a voltage, and an AC motor 105 driven by an AC voltage output from the inverter 104. Although the above-described wiring conductor of FIG. 26 can be applied to the smoothing capacitor 103, it is difficult to apply the wiring conductor to the inverter section and the converter section, and a problem such as an overvoltage accompanying the wiring inductance occurs. Here, the neutral point clamping method is shown as a representative example, but any power converter, if it is a converter or an inverter constituted by semiconductor switching elements, similarly has a problem associated with wiring inductance. The converter 102 and the inverter 104
The same applies to any semiconductor switching element used for the above.

FIG. 23A is a diagram showing a part of a conventional converter circuit or inverter circuit using a self-extinguishing type semiconductor element. Although a circuit using GTO is shown for convenience, a circuit in which GTO is replaced with IGBT corresponds to the IGBT peripheral circuit including the IGBT in FIG. FIG. 23 (2) shows the waveform of the anode-cathode voltage V _{AK and the} anode-cathode current I _AK when the current of the self-extinguishing semiconductor device is cut off. Here, GTO31 is used as a self-extinguishing type semiconductor element for convenience. FIG.
An operation when the GTO 31 is turned off in the circuit shown in (1) will be described. The current that has been conducting while the GTO 31 is in the ON state is changed to the snubber diode 32 during the process in which the GTO 31 enters the turn-off operation and transitions to the OFF state.
It is bypassed to a snubber circuit composed of a snubber capacitor 33 and the like. At this time, the charging voltage V _CS is generated in the snubber capacitor 33 by the bypassed current. Current change rate di / dt flowing into snubber circuit immediately after turn-off
Is the same as the current falling rate dI _AK / dt of the GTO 31.
Further snubber circuit and the parasitic inductances 34 internal inductance is the sum of such wiring inductance and the snubber capacitor 33 in the wiring that connects the GTO31, inductance current change rate of the I _AK di / dt
And a voltage _VLS determined by the product of Furthermore, to generate a voltage V _DS due to the current change rate di / dt in the snubber diode 32. Therefore, the spike voltage V _DSP is applied to the GTO 31 as the sum of the charging voltage V _CS of the snubber capacitor 33, the induced voltage V _LS of the parasitic inductance 34 in the snubber circuit, and the transient voltage V _DS of the snubber diode 32. You. If the V _DSP becomes large, the GTO 31 may be destroyed, and the GTO 31 must be used in a safe operation area. Therefore, the parasitic inductance 34
Is large, there is also a problem that the utilization factor of the element is reduced, for example, the breaking current must be reduced. Therefore, the parasitic inductance 34 in the snubber circuit must be kept small.

Further, when the GTO 31 completes the turn-off operation, the voltage accompanying di / dt does not occur, and the voltage V _AK applied to both ends of the GTO 31 is only the charging voltage V _CS of the snubber capacitor 33. However, the energy stored in the parasitic inductance 34 of the snubber circuit generates an excessive charging voltage of the snubber capacitor 33, and the clamp diode 38 and the clamp capacitor 36
Thereby applying a maximum voltage V _DM parasitic inductance coupled with GTO31 in composed clamp circuit and the like. In other words, an increase in the respective portions of the parasitic inductance causes an increase in spike voltage V _DSP and the maximum applied voltage V _DM. G
The element rating is also determined for the maximum applied voltage _VDM of TO, and if the current is cut off beyond this, the element will be destroyed. For this reason, even when the parasitic inductance 37 is large, there has been a problem that the element utilization rate decreases, for example, the breaking current must be reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and the self-extinguishing type semiconductor element has a large rating, and a snubber circuit or a clamp circuit functioning as a protection circuit for the semiconductor element is enlarged. However, an object is to obtain a power converter that can reduce parasitic inductance in a circuit such as a snubber circuit and a clamp circuit.

[0008]

The above object is achieved by the following means. The first means arranges, near the first conductor for wiring, a second conductor which is independent of the first conductor and generates an induced current in response to a change in current of the first conductor. Things.

The second means includes a second conductor which is independent of the first conductor and generates an induced current in response to a change in the current of the first conductor, near the first conductor for wiring. And electrically connecting the first conductor and the second conductor at at least one point.

The third means is to arrange a second conductor independent of the first conductor near the first conductor for wiring, and to connect the first conductor and the second conductor at least at one point. It is a thing to connect.

[0011] The fourth means is independent of the first conductor for wide wiring so that at least a part and a part not overlapping the projection surface in the thickness direction of the first conductor for wide wiring are formed. A second conductor is disposed close to the first conductor, and at least one point on the second conductor is electrically connected to the adjacent first conductor.

The fifth means is that the second conductor having the same width as the first conductor for the wide wiring is formed such that the portion overlapping the projection surface of the first conductor in the thickness direction is 10 to 60% of the entire width. The first conductor is disposed in parallel with the first conductor so as to be in a range, and at least one point on the second conductor is electrically connected to the first conductor adjacent to the first conductor.

The sixth means is a projection means for projecting the first conductor in the thickness direction of the first conductor for two wide wirings whose wide faces face each other so as to cancel the magnetic flux due to the reciprocating current. A second conductor is disposed in close proximity to the first conductor such that at least a portion of the second conductor overlaps and a portion of the first conductor does not overlap, and at least one point on the second conductor is in proximity to the first conductor. Are electrically connected to the conductors.

According to a seventh aspect, when the semiconductor switching element is turned on or turned off, at least a portion of the first conductor for wide wiring, which increases or decreases the current, overlaps with and is partially overlapped with the projection surface in the plate thickness direction. A first conductor, which is arranged close to the first conductor and is independent of the first conductor so as to have a non-overlapping portion, and at least one point on the second conductor which is close to the first conductor; It is electrically connected to.

According to each of the above means, an induced current in the second conductor is generated in a direction opposite to the main current due to a change in the main current of the first conductor. For this reason, the inductance of the first conductor is reduced.

Other specific means will be apparent from the following description.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. 1 shows a wide wiring conductor in a power converter according to a first embodiment of the present invention. A first conductor 1 for connecting circuit components and through which a circuit current flows, and a first conductor 1
And the second conductor 2 through which the circuit current does not flow. The second conductor 2 wider than the first conductor 1 is placed at a certain distance from the first conductor 1 so that the projection surface of the first conductor 1 from the thickness direction is included in the second conductor 2. And are arranged in parallel. The second conductor 2 is a conductor provided separately from the component connection conductor in the circuit. In this case, the second conductor 2 is connected to the first conductor 1 at one point by a conductive screw 5 to fix the potential. . This can prevent corona discharge between the conductors. Note that the ring-shaped spacer 7 is provided to keep the first conductor 1 and the second conductor 2 apart by a certain distance. This spacer 7 may be either a conductor or an insulator.
Here, a wide conductor is defined as a conductor whose width dimension is larger than its thickness dimension. It is preferable that the width of the conductor 1 be twice or more the thickness in order to reduce the self-inductance.

The self-inductance of the first conductor 1 is represented by Ls
Assuming that the mutual inductance between the first conductor 1 and the second conductor 2 is M, the inductance L of the first conductor 1 when the second conductor 2 is arranged is as follows: .

[0019]

L = Ls1 + M (Equation 3)
From this equation, it can be seen that the inductance L of the first conductor 1 can be reduced as the sign of the mutual inductance M is minus and the absolute value of M is larger.

Next, the operation when a circuit current is applied to the first conductor 1 will be described. Assuming that the current direction of the first conductor 1 is the direction of the arrow (I1) shown in the figure, the second conductor 2 has a direction directly below the first conductor 1 and opposite to the current of the first conductor 1. Further, a current flows in a portion far away from the first conductor 1 in the same direction as that of the first conductor 1. This can be explained by a phenomenon called electromagnetic induction. That is, in order to cancel the magnetic flux generated by the current of the first conductor 1, a current having a direction opposite to that of the first conductor 1 is generated in the second conductor 2 immediately below the first conductor 1. In the second conductor 2 which has no connection with a portion other than the connection portion of the electrically conductive screw 5, the induced current needs to return to the starting point in a circular loop. (I2) after flowing in a portion far away from the first conductor 1 so as to avoid the magnetic flux of (I2). The current generated in the second conductor 2 in the same direction as that of the first conductor 1 has an effect of increasing the magnetic flux of the first conductor 1. Therefore, in order to reduce the magnetic flux of the first conductor 1, the electromagnetic coupling between the first conductor 1 and the second conductor 2 is increased, and the width of the second conductor 2 is further increased. It is necessary to weaken the effect of increasing the magnetic flux of the first conductor 1. In other words,
The fact that the effect of the reverse current induced in the second conductor 2 is large and the effect of the current in the same direction is small is
Is to make the sign of M negative, and to increase the absolute value.

FIG. 3 shows the results of three-dimensional analysis of the relationship between the distance between these conductors and the wiring inductance using the model shown in FIG. In the model of FIG. 2, the first conductor 1 and the second conductor 2 are arranged at a fixed distance d and the center line in the width direction is aligned. FIG. 3 shows the relationship between the distance d between the first conductor 1 and the second conductor 2 and the inductance L of the first conductor 1 depending on the width of the second conductor 2. This result shows that if the width of the second conductor 2 is the same as that of the first conductor 1 and the value of the inductance is the same as in the case where the second conductor is not provided, there is no effect of reducing the inductance. If the width is increased beyond the width of the first conductor 1, the effect of reducing the inductance increases as the width increases, and the effect of reducing the inductance decreases as the distance between the first conductor 1 and the second conductor 2 decreases. Is shown. This is because the coupling between the first conductor 1 and the second conductor 2 is increased by shortening the distance between the first conductor 1 and the second conductor 2, and the width of the second conductor 2 is increased by increasing the width of the second conductor 2. It is nothing less than weakening the effect of increasing the magnetic flux. In the model of FIG.
Is 75 mm in width and 6 mm in thickness. However, if the conductor is a wide conductor, the inductance reduction effect is almost the same as that in FIG. Since the distance between the first conductor and the second conductor is substantially saturated in a region of 3 mm or less, the distance between the first conductor 1 and the second conductor 2 may be 3 mm or less. However, at this time, the distance is set to 0
In the case of mm, the first conductor 1 and the second conductor 2 come into contact with each other and the effect of the second conductor 2 is lost, so that the distance can be secured by sandwiching a thin insulating sheet. is necessary. In FIG. 2, the second conductor 2 and the first conductor 1
Are not connected, but the characteristics when both are connected at one point are the same as the results in FIG. As a connection method, fixing with a conductive screw, welding, soldering, or the like can be considered.
In any case, it is only necessary to be electrically connected. Also,
When both ends of the first conductor 1 are connected at a plurality of places as in the case where both ends in the longitudinal direction are connected to the second conductor 2, the second conductor
Since the conductor 2 serves as a current bypass for the first conductor 1, the effect of the present invention is not sufficiently exhibited between the connection points. However, since the wiring inductances of the first conductor and the second conductor are connected in parallel between the connection points, the self-inductance can be reduced to some extent. Therefore, the first conductor and the second conductor may be partially electrically connected at a plurality of locations. That is, a circuit current may partially flow in the second conductor.

FIG. 22 shows the overall configuration of the power converter of this embodiment. In this regard, the same applies to the following embodiments.

Embodiment 2 FIG. 4 shows a wide wiring conductor in a power converter according to a second embodiment of the present invention. A second conductor having the same width as the first conductor 1
Are moved in parallel in the width direction so as to form an overlapping portion on the projection plane of the first conductor 1 in the plate thickness direction, and are further arranged at a fixed distance. Also, the first conductor 1 and the second conductor 2 are connected at one point by the conductive screw 5,
A spacer 7 is provided to maintain the interval between the two.
4 differs from FIG. 1 in the width of the second conductor 2. Specifically, in FIG. 1, the second conductor 2 is wider than the first conductor 1 in FIG.
FIG. 4 shows that the projection surface of the first conductor 1 in the plate thickness direction all overlaps with the second conductor 2.
Then, the first conductor 1 and the second conductor 2 have the same width, and the projection surface of the first conductor 1 overlaps with a part of the second conductor 2.
It also has non-overlapping parts.

The operation when a current is applied to the first conductor 1 is the same as that shown in FIG. 1, and in the second conductor 2 where the projection surface of the first conductor 1 in the thickness direction overlaps. A current in a direction opposite to that of the first conductor 1 is induced, and a current in the same direction is induced in a portion not overlapping.

FIG. 6 shows the inductance of the first conductor 1 when the ratio of the portion of the second conductor 2 overlapping the projection surface in the thickness direction of the first conductor 1 in the model of FIG. 5 is changed. It is shown. This result indicates that when a = 0, that is, when the projection surface of the first conductor 1 in the thickness direction completely overlaps the second conductor 2, there is no effect of reducing the inductance of the first conductor 1 (in FIG. 3, Conductor 2 or W = 75 mm). When the value of a is increased, that is, when the second conductor 2 is moved in parallel in the width direction, the effect of reducing the inductance of the first conductor 1 gradually increases, and reaches a maximum at a certain point. And a
And the inductance of the first conductor 1 is reduced until the projection width of the first conductor 1 with respect to the plate thickness direction does not overlap the second conductor 2 at all. The effect weakens. In other words, the second conductor 2 having the same width as the first conductor 1 is brought into close proximity to the second conductor 2 in a range of 10% to 60% on the plane of projection of the first conductor 1 in the thickness direction. When they are arranged in parallel with each other, the effect of reducing the inductance of the first conductor 1 is increased. In the model shown in FIG. 5, the width of the first conductor is set to 75 mm and the thickness is set to 6 mm as an example.

Although the electrical connection relationship between the first conductor 1 and the second conductor 2 is also omitted in the model of FIG. 5, when there is an electrical connection portion, the effect of reducing inductance can be obtained. Is as described above.

Third Embodiment FIG. 7 shows a structure of a wide wiring conductor in a power converter according to a third embodiment of the present invention. The first conductor 1 and the second conductor 2 are arranged at a fixed distance, and the second conductor 2 is arranged so that there is a portion that does not overlap with a portion that overlaps the projection surface of the first conductor 1 in the thickness direction. ing.
7 differs from FIG. 5 in the width of the second conductor 2. Specifically, in FIG. 5, the second conductor 2 has the same width as the first conductor 1 in FIG.
In FIG. 7, the width of the second conductor 2 is arbitrary. The second conductor 2 is the same as that of FIG. 5 in that the second conductor 2 is arranged so as to have an overlapping portion and a non-overlapping portion on the projection plane of the first conductor 1 in the plate thickness direction. Also, the width of the non-overlapping portion is represented by a.

FIG. 8 shows the result of three-dimensional analysis using the model of FIG. FIG. 8 shows the inductance of the first conductor 1 when a and b in FIG. 7 are changed. From this result, when a is increased, that is, by increasing the portion of the first conductor 1 that does not overlap the second conductor 2 on the projection plane in the thickness direction of the first conductor 1, the effect of reducing inductance is increased. It can be understood that the inductance reduction effect can be sufficiently obtained by widening the portion overlapping with the second conductor 2 on the projection plane in the thickness direction of the first conductor 1 to about half of the first conductor 1. . Further, it can be considered that the reduction effect appears from the figure when the second conductor 2 is arranged so as to overlap the width of the first conductor 1 by 10% or more. Furthermore, even if the width of the portion where the first conductor 1 and the second conductor 2 do not overlap each other is set to be equal to or more than の of the width of the first conductor 1, a reduction effect is considered to be exhibited. Therefore, in order to reduce the inductance, the second conductor 2 is arranged so as to overlap the width of the first conductor 1 by 10% or more, or the first conductor 1 and the second conductor 2 are May be arranged so that the width of the portions that do not overlap with each other is equal to or more than 幅 of the width of the first conductor 1, or a combination thereof.

The width of the second conductor 2 is set to 2 in the first conductor 1 by setting the overlapping portion to half of the first conductor 1.
The configuration in which another second conductor 2 is added symmetrically about the dividing center line is the same as FIG. Therefore, the configuration of FIG. 1 has an inductance reduction effect about twice that of the configuration of FIG. However, in a case where the second conductor 2 can be spread only on one side of the first conductor 1 due to a limitation of a mounting space or the like, the configuration shown in FIG. 7 is effective. Although the electrical connection relationship between the first conductor 1 and the second conductor 2 is also omitted in the model of FIG. 7, it is described above that the effect of reducing inductance is obtained even when there is an electrical connection portion. It is as follows.

Next, the thickness of the second conductor 2 will be described. FIG. 11 shows the inductance of the first conductor 1 when the thickness of the second conductor 2 is changed. In each case, the first conductor 1 is 75 mm wide, 6 mm thick, and 1000 mm long.
mm, the length of the second conductor 2 is 1000 mm, and in the case (1), the width w of the second conductor 2 is 150 mm in the arrangement shown in FIG.
mm, the distance d between the first conductor 1 and the second conductor 2 is 1 mm,
In the case (2), the second conductor 2
Is 150 mm, the distance d between the first conductor 1 and the second conductor 2 is 0.1 mm, and in the case of (3), the first conductor 1 and the second conductor 2 are arranged as shown in FIG. Distance d is 1 mm, a = 3
7.5 mm, that is, the case where the overlapping portion between the projection surface of the first conductor 1 in the plate thickness direction and the second conductor 2 is 50% is shown. According to these results, in any case, since the inductance reducing effect changes at the boundary of the thickness of the second conductor 2 of about 1 mm, it is sufficient that the thickness of the second conductor 2 is 1 mm or more. I understand. When the second conductor 2 is thinned,
It is considered that the inductance reduction effect is weakened because the resistance increases. In this analysis, the first conductor 1
It is assumed that copper is used for the second conductor 2 and the thickness of the second conductor 2 is further reduced by using a material having a lower resistivity than copper for the second conductor 2. It is possible.

Fourth Embodiment FIG. 9 is a sectional view and a plan view showing a structure of a wide wiring conductor in a power converter according to a fourth embodiment of the present invention. The second conductor 2 is brought close to and parallel to the first conductor 1 at a fixed distance so as to form an overlapping portion and a non-overlapping portion on the projection plane of the first conductor 1 in the plate thickness direction,
Two second conductors 2 are arranged symmetrically about the center line SS ′ of the first conductor 1. Symbols 91 and 92 in the cross-sectional view in FIG. 9 indicate the direction of the current. First conductor 1
The symbol 91 in the cross-sectional view of FIG. 7 indicates that the flow from the back side of the paper surface to the front side, and the symbol 92 in the cross-sectional view of the second conductor 2 indicates that the flow is from the front side of the paper surface to the back side. In other words, in the region where the second conductor 2 overlaps the plane of projection of the first conductor 1 in the plate thickness direction, a current in the opposite direction to the first conductor 1
Further, it is shown that a current is induced in the same direction as the first conductor 1 in a region that does not overlap and is far from the first conductor 1.

FIG. 9 differs from FIG. 1 in the method of arranging the second conductor 2. Specifically, in FIG. 1, one wide conductor is arranged, whereas in FIG. 9, the second conductor 2 is divided into two, and each of the second conductors 2 is moved outward in parallel with respect to the width. In addition, the central portion of the projection surface of the first conductor 1 in the thickness direction does not overlap with the second conductor 2. It is apparent from the results of FIGS. 6 and 8 that the first conductor 1 has an effect of reducing the wiring inductance even if the central portion of the projection surface does not overlap the second conductor 2. In FIG. 9, the electrical connection between the first conductor 1 and the second conductor 2 is omitted. The second conductor 2 shown in FIG.
Can be said to be equivalent to the second conductor 2 shown in FIG. 1 in which a slit is formed at the center of the second conductor 2 as shown in FIG. Therefore, even when a slit is formed in the second conductor 2 shown in FIG. 1, the inductance of the first conductor 1 is reduced. Furthermore, if the magnetic flux leakage of the first conductor 1 can be made substantially equal to that of the second conductor 2 having the above-described slit in a portion overlapping the projection surface of the first conductor 1 in the plate thickness direction, the second conductor 2 Even when the conductor 2 is formed in a mesh shape, there is an effect of reducing the inductance of the first conductor 1 as in the case of FIG.

Next, FIG. 12 shows the result of analyzing the relationship between the frequency and the inductance reduction. In each case, the first conductor 1 is 75 mm wide, 6 mm thick, 1000 mm long,
The length of the second conductor 2 is 1000 mm, the case of (0) is the first conductor 1 alone without the second conductor 2, and the case of (1) is the second conductor 2 in the arrangement shown in FIG. Width w of 150m
m, the distance d between the first conductor 1 and the second conductor 2 is 1 mm,
In the case (2), the width w of the second conductor 2 is set to 150 mm and the distance d between the first conductor 1 and the second conductor 2 in the arrangement shown in FIG.
Is 0.1 mm, and the case of (3) is the first in the arrangement shown in FIG.
Distance d between conductor 1 and second conductor 2 is 1 mm, a = 37.5 m
m In other words, the projection surface of the first conductor 1 in the thickness direction
2 shows a case where the overlapping portion of the conductor 2 is 50%.

From the results shown in FIG. 12, in each case, 500
It can be seen that the inductance reducing effect changes greatly around Hz, and the effect of reducing the inductance of the first conductor 1 by the second conductor 2 appears from the frequency region where the skin effect appears. The skin effect is a phenomenon in which when the frequency of the current increases, the current gathers on the surface and the internal current decreases. At this time, the internal conductor hardly contributes to the conduction of electric current, and the apparent cross-sectional area decreases and the resistance increases. The same is true for magnetic flux. The penetration depth (skin depth) δ of the magnetic flux can be expressed by the following equation.

[0035]

(Equation 6)

Here, ω is the angular frequency of the current flowing through the first conductor 1, σ is the conductivity of the first conductor 1, and μ is the magnetic permeability of the first conductor 1. As described above, in a power converter using a semiconductor switching element, there is a problem that a surge voltage is applied to the semiconductor element due to wiring inductance or the like during switching of the semiconductor switching element. The switching frequency of a semiconductor element is very high, several tens of kHz or more, and usually exceeds the frequency at which the skin effect occurs. Therefore, it can be seen that the above wiring structure exhibits an inductance reducing effect at the time of semiconductor switching.

In the conductor arrangement shown in FIG.
Although the two second conductors 2 are symmetrically arranged, if the second conductors 2 are arranged so that a portion overlapping the projection surface of the first conductor 1 with respect to the plate thickness direction and a portion not overlapping are necessarily formed, the inductance is increased. Since the reduction effect is obtained, the second conductors 2 do not need to be arranged symmetrically, and the widths of the two second conductors 2 do not need to be the same.

Fifth Embodiment FIG. 13 is a sectional view showing the structure of a wide wiring conductor in a power converter according to a fifth embodiment of the present invention. First
The first conductor 1 and the second conductor 2 are separated by a certain distance, and the second conductor 2 has an overlapping portion and a non-overlapping portion on the projection surface of the first conductor 1, and the center line of the first conductor 1 is The two second conductors 2 are symmetrically arranged. FIG. 13A is the same as FIG. In FIG. 13, the electrical connection between the first conductor 1 and the second conductor 2 is omitted.

In FIG. 3, a first conductor 1 and a second conductor 2
The results of analysis with the distance between the two indicate that the closer this distance is, the greater the inductance reduction effect is. Further, in FIG. 11, the thickness of the second conductor 2 and the first conductor 1
In the case where copper is used for the second conductor 2, if the thickness of the second conductor 2 is 1 mm or more, the effect of reducing inductance is large. When a thin second conductor 2 is brought close to the first conductor 1, it is very difficult to support each conductor in the air, and in particular, the method of supporting the second conductor 2 is problematic. Therefore, (2) to (5) of FIG. 13 show a method of fixing the first conductor 1 and the second conductor 2 by bonding or screwing through the insulator 3.

In (1) to (5), the arrangement relationship between the first conductor 1 and the second conductor 2 is the same, and the difference is that
Of the insulator 3 sandwiched between the first conductor 2 and the second conductor 2. As a material used for the insulator 3, mica, glass epoxy, fiber reinforced resin, or the like may be selected from the viewpoints of insulation properties, cost, and ease of processing. In any case, the distance between the first conductor 1 and the second conductor 2 can be kept constant, so that the effect of reducing the inductance of the first conductor 1 can be exhibited.

In FIG. 13, two conductors are shown as symmetrically arranged as the second conductor 2.
The second conductors 2 need not be bilaterally symmetrical and do not need to have the same width as long as they can be arranged so that there is a portion that does not overlap with a portion that overlaps on the projection plane of the first conductor 1 in the plate thickness direction. Also, when one conductor is fixed as shown in FIGS. 1 and 5, it is apparent that the effect of reducing the inductance of the first conductor 1 can be exerted by similarly sandwiching the insulator.

Embodiment 6 FIG. 14 is a sectional view showing the structure of a wide wiring conductor in a power converter according to a sixth embodiment of the present invention. With a certain distance between the wide first conductor 1 and the second conductor 2, there are some portions of the second conductor 2 that do not overlap with the portion of the first conductor 1 that overlaps the projection plane in the plate thickness direction.

FIG. 14A shows a first conductor 1 and a second conductor 2 connected via an insulating material 4. A plurality of folds are formed on the end surface of the insulating material to increase the creepage distance. First
When the distance between the first conductor 2 and the second conductor 2 is large, it is effective as a method of increasing the creepage distance of the insulation. Further, the first conductor 1, the second conductor 2 and the insulating material 4 are fixed with insulating screws 6 to fix them. A fiber reinforced resin or the like may be used for the insulating screw.

FIG. 14B shows a state in which the first conductor 1 and the second conductor 2 are fixed via the insulator 3 as in FIG. 13, and the insulating screw 6 is used as in FIG. Screwed. Although the width of the second conductor 2 and the insulator 3 is shown as being the same, the insulator 3 may be wider than the second conductor 2 in order to secure the creepage distance of the insulation. Either method can be applied even when there are a plurality of second conductors 2, and it is clear that the effect of reducing the inductance of the first conductor 1 can be exerted. In this case, it is important to fix the first conductor 1 and the second conductor 2, and not limited to an insulating material such as an insulating spacer or an insulating screw, but any other material that can be electrically insulated. Connection means may be used.

Seventh Embodiment FIG. 15 is a view showing the structure of a wide wiring conductor in a power converter according to a seventh embodiment of the present invention. The second conductor 2 is a conductor wider than the wide first conductor 1.
The arrangement relationship between the first conductor 1 and the second conductor 2 is the same as that of FIG. 1, and the first conductor 1 and the second conductor 2 are arranged at a certain distance. FIG. 15 differs from FIG. 1 in a method for maintaining the distance between the first conductor 1 and the second conductor 2. In FIG. 1, the spacer 7 is used.
5, the insulating spacer 8 is used. In the figure, the width of the insulating spacer 8 is the same as the width of the first conductor 1,
If the distance between the first conductor 1 and the second conductor 2 can be kept constant,
The insulating spacer 8 may have any width.

In FIG. 15, similarly to FIG. 1, a part of the first conductor 1 and the second conductor 2 are electrically connected by the conductive screw 5.

Here, the meaning of the electrical connection between the two will be described. If the electric potential of the second conductor 2 is left floating, the electric potential of the second conductor 2 increases as the energization of the first conductor 1 is repeated. Further, a corona that discharges the electric charge accumulated in the second conductor 2 is generated, and an erroneous pulse is generated in the gate drive circuit of the semiconductor switching element, so that the semiconductor switching element may malfunction.
In addition, there is a problem that the components constituting the power converter deteriorate due to the corona and the life is remarkably shortened. Therefore,
In order to avoid such a problem, it is necessary to electrically fix the potential of the second conductor 2. As shown in FIG. 15, if a part of the second conductor 2 can be electrically connected to the first conductor 1, there is no possibility that corona is generated. As described above, care must be taken when a plurality of connection points are provided in the longitudinal direction of the first conductor 1, but providing a plurality of connection points in the width direction does not pose any problem. For example, this corresponds to a case where the both ends in the width direction of the first conductor 1 are connected to the second conductor 2 by a conductive screw or the like.

FIG. 16 is a view showing a method for fixing the first conductor 1 and the second conductor 2. The arrangement method of the first conductor 1 and the second conductor 2 is the same as that of FIG.
Also, the first conductor 1 and the second conductor 2 are screwed with the conductive screw 5 in the same manner as in FIG. 1 for fixing the potential of the second conductor 2 to prevent corona. It is.

FIG. 16 is different from FIG. 1 in that the first conductor 1 and the second conductor 2 are screwed with an insulating screw 6,
Furthermore, in order to maintain the distance between the first conductor 1 and the second conductor 2, a screw 6 is inserted between the two conductors with a ring-shaped insulating spacer 8 interposed therebetween. Even if a part is fixed with the conductive screw 5, the method of fixing the first conductor 1 and the second conductor 2 is unstable. Therefore, the conductive screw 6 of the second conductor 2
It is necessary to fix a portion different from the portion screwed with the first conductor 1. When this is screwed with a conductive screw, a current in the same direction as the first conductor 1 flows through the second conductor 2. That is, the second conductor 2 is the first conductor 1
Function as a bypass. Therefore, screwing with the insulating screw 6 is required. When screwing with the insulating screw 6, it goes without saying that the inductance reducing effect is not impaired even if insulation is provided between the first conductor 1 and the second conductor 2. At this time, the insulator and the first conductor 1 or the insulator and the second conductor 2 may be bonded.

Eighth Embodiment FIG. 17 is a diagram showing a structure of a wiring conductor in a power converter according to an eighth embodiment of the present invention. 17 differs from FIG. 1 in that the shape of the second conductor 2 in FIG. 1 is a single plate that is not bent, whereas in FIG. A portion that does not overlap the second conductor 2 on the projection plane in the thickness direction is bent vertically. The bent portion in FIG. 17 is a portion that functions as a return path of the induced current generated in the second conductor 2, and the bent portion does not change the distance from the first conductor 1. Has the same inductance reducing effect as the configuration shown in FIG.

Also in this case, an insulator is sandwiched between the first conductor 1 and the second conductor 2, or the first conductor 1 and the second conductor 2 which sandwich the insulator are conductive. It is clear that the effect of reducing the inductance of the first conductor 1 can be exhibited even when the screws are screwed with a conductive screw or an insulating screw. Regarding the bent portion of the second conductor 2, if any part of the bent portion of the second conductor 2 overlaps with the second conductor 2 on the projection plane in the thickness direction of the first conductor 1, the first conductor 1 may be bent anywhere. There is an effect of reducing the inductance of the conductor 1. In addition, although the case where it was bent vertically was described in the figure, the bending method may not be vertical,
Also, it may be bent a plurality of times.

Embodiment 9 FIG. 18 is a view showing a cross section of a wide wiring conductor in a power converter according to a ninth embodiment of the present invention. In order to cancel the magnetic flux due to the reciprocating current, the wide directions of the first conductor 11 and the first conductor 12 whose current directions are opposite to each other face each other, and further the first conductor 11 and the first conductor 12 The wide second conductor 21 and the second conductor 22 are arranged at a certain distance from the first conductor, respectively. Symbols 91 and 92 in the figure indicate the direction of the current in each conductor.

It is known that the inductance of the first conductor 11 and the first conductor 12 is reduced by facing the first conductor 11 and the first conductor 12 on a wide surface. By arranging the second conductor 21 and the second conductor 22 close to each other on the first conductor, the inductance can be further reduced.

The second conductor has the first
Although the case where it is provided for the conductor is shown, it may be provided for either one. Of course, when applying such an arrangement method, an insulator may be inserted between the first conductor and the second conductor, or the first conductor and the second conductor or the first conductor and the second conductor may be inserted. It is clear that the effect of reducing inductance is not impaired even if the insulator and the insulator are fixed with a conductive screw or an insulating screw. In FIG. 18 as well, in order to fix the potentials of the second conductors 21 and 22, it is necessary to electrically connect to the first conductors 11 and 12 which are close to each other, but this is omitted in the figure. doing.

Embodiment 10 FIG. 19 shows a tenth embodiment according to the present invention, showing wiring mounting of a snubber circuit for protecting a semiconductor switching element from a surge when the semiconductor switching element is turned off. As a semiconductor switching element, a GTO having a flat electrode surface is shown as an example. 31 is GTO, 32
Is a snubber diode, 33 is a snubber capacitor, and 39 is a cooling fin. GTO31 and snubber diode 32
Is an element having a flat electrode surface, and forms an integrated stack via cooling fins 39. The stack and the snubber capacitor 33 are connected by the first conductor 1. In the input / output terminal portion of the snubber capacitor 33 of the first conductor 1, the wide surfaces of the first conductors 1 are arranged close to each other. To reduce inductance. Furthermore, the first
In a partial section of the conductor 1, a second conductor 2 wider than the first conductor 1 is arranged close to the projection surface of the first conductor 1 in the plate thickness direction. I have. Due to such mounting, the effect of reducing inductance is exhibited not only in the section where the magnetic fluxes cannot be canceled out between the first conductors 1 but also in the section where the magnetic fluxes can be canceled out between the first conductors 1. I do. Further, the second conductor 2 and the first conductor 1 are connected by a conductive screw 5,
Of the conductor 2 is fixed.

The semiconductor switching element in this case may be a reverse conducting GTO thyristor, IGBT, SI thyristor, SIC or the like as long as the electrode surface is flat. Also, the case where the GTO 31 and the snubber diode 32 are pressed against the same stack has been described.
Also, when pressed into separate stacks for reasons such as the size of the elements of the snubber diode 32 and the
By arranging the above-described second conductor on the first conductor connecting the components forming the snubber circuit, the effect of reducing the parasitic inductance in the snubber circuit is exhibited. That is, the second conductor is connected to the first conductor connecting the snubber circuit components regardless of the arrangement of the components constituting the snubber circuit.
The effect of reducing the parasitic inductance in the snubber circuit can be exhibited by arranging the conductors. Further, the second conductor can be applied to a first conductor having an L-shaped side view as shown in FIG. 19 or a first conductor having an uneven width as a special case. In any case, the second conductor may be arranged so as to at least partially overlap the projection surface of the first conductor in the plate thickness direction and not to partially overlap. In FIG. 19, auxiliary components used for a free wheel diode, a snubber resistor, a snubber energy regenerating circuit, and the like, an insulator, a press-contact member, and the like are omitted, but the present invention can be applied to the basic structure shown here. Is clear.

Embodiment 11 An eleventh embodiment of the present invention will be described with reference to FIGS. FIG. 21A is a diagram illustrating a snubber circuit and a clamp circuit that protect the semiconductor switching element from a surge generated when the semiconductor switching element is turned off. FIG. 20 shows a side view when this part is mounted. As the semiconductor switching element, a GTO having a flat electrode surface as in FIG. 19 is shown as an example. The snubber circuit including the snubber diode 32 and the snubber capacitor 33 has the same configuration as that of FIG. 19, and the second conductor 2 is arranged close to the wide first conductor 1 in the snubber circuit.

In FIG. 20, a diode 35, a clamp capacitor 36, and a clamp diode 38 are added to the circuit configuration of FIG. The second conductor 2 is also arranged close to the first conductor 1 of this clamp circuit. The method of arranging the second conductor 2 with respect to the first conductor 1 is such that in any case, at least a part of the first conductor 1 that overlaps on the projection plane from the thickness direction of the first conductor 1 and a part that does not overlap, It is important to have
Further, the second conductor 2 is connected to the first conductor 1 by a conductive screw 5 to fix the potential of the second conductor 2, and a spacer 7 is inserted to maintain a distance between the two. The parasitic component of the first conductor 1 connected to the clamp capacitor 36 corresponds to the parasitic inductance 37 and 42 in FIG. The parasitic inductance includes the internal inductance of the clamp capacitor, but in a normal mounting, the ratio of the inductance component of the wiring conductor is larger.

In FIG. 20, auxiliary components used for a free wheel diode, a snubber resistor, a snubber energy regenerating circuit and the like are omitted, but it is apparent that the present invention can be applied to the basic structure shown here. Further, insulators and pressure contact members are omitted.

Usually, the snubber circuit is mounted with the highest priority as the surge absorbing portion of the self-extinguishing type semiconductor element. this is,
This is because the parasitic inductance 34 in the snubber circuit needs to be sufficiently small so that the spike voltage V _DSP generated when the self-extinguishing type semiconductor element is turned off can be suppressed. Therefore, in FIG. 20, the GTO 31 and the snubber diode 32 that constitute the snubber circuit are adjacently pressed into the same stack.

[0061] It must be noted in the following V _DSP is the maximum voltage V _DM applied to GTO31. FIG.
In the circuit shown in FIG. 5, _VDM is determined by a series capacitor group composed of the clamp capacitor 36 and the snubber capacitor 33, a parasitic inductance 37 in the clamp circuit, and a series inductance group composed of the parasitic inductance 34 in the snubber circuit. LC resonance. In these LC circuits, if there is no inductance component, the resonance phenomenon does not occur, so that the capacitor is not overcharged. Therefore, when the applied voltage of the GTO also reaches a certain value similarly to the applied voltage of the capacitor, the GTO enters a steady state and maintains a constant value.

However, it is impossible to eliminate the parasitic inductance in the normal mounting. When there is a parasitic inductance, a value obtained by subtracting a steady value from the maximum voltage applied to the GTO is a voltage increase due to the parasitic inductance. Therefore, it is necessary to minimize the parasitic inductance in the LC resonance circuit. However, as mentioned above, to give top priority to the implementation of the snubber circuit, the GTO
And the diode are pressed together as an integrated stack,
By increasing the distance between the terminals on the semiconductor element side connected to the clamp capacitor, and by adding a semiconductor element such as a free-wheel diode, not shown in the figure, to the terminal on the semiconductor element side connected to the clamp capacitor Due to the reason that the distance is long and the capacitance of the clamp capacitor is larger than the capacitance of the snubber capacitor, the volume of the clamp capacitor is large.
Therefore, the parasitic inductance of the clamp circuit necessarily has a large value as compared with the parasitic inductance of the snubber circuit. In addition, since a single loop forming the clamp circuit is increased, a portion where a magnetic flux canceling effect using a reciprocating current can be used is reduced, thereby increasing the parasitic inductance. Therefore, the parasitic inductance can be reduced by disposing the second conductor 2 close to the first conductor 1 of the clamp circuit as described above.

FIG. 20 shows a case where the GTO 31 and the diodes 32, 35, and 38 have the same diameter and are pressed against the same stack. The use of the second conductor 2 has an effect of reducing inductance.
As described above, by applying the present invention to a portion which has not had the effect of reducing the inductance, the voltage applied to the semiconductor switching element can be reduced, and the power converter can be operated safely. Further, when the breaking current is reduced below the rating, the device utilization is improved.

Next, a portion where the effect of reducing the parasitic inductance is large will be described based on a specific circuit. FIG.
3 shows a part of an inverter circuit or a converter circuit using a semiconductor switching element. The inductances shown are all parasitic inductances and GT
Anode reactors and loads that reduce the current change rate of O31 are omitted. In FIG. 21A, the clamp capacitor 36 is connected to the negative terminal side of the smoothing capacitor 40. In FIG. 21B, the clamp capacitor 36 is connected to the positive terminal side of the smoothing capacitor 40. First, the operation when the GTO 31 is turned off will be described with reference to FIG. When the GTO 31 is energized in the ON state, current is supplied from the plus terminal of the smoothing capacitor 40 to the load via the GTO 31. When the GTO 31 enters the turn-off operation, the GTO 31
Flows into the snubber diode 32 and the snubber capacitor 33 to charge the snubber capacitor 33. Note that the clamp capacitor 36 is charged to a predetermined voltage, and no current flows into the clamp capacitor 36 until the charged voltage of the snubber capacitor 33 reaches the charged voltage of the clamp capacitor 36. At this time, a spike voltage is generated by the parasitic inductance 34 in the snubber circuit.
As described above, No. 4 must be suppressed to the extent that the device specifications are satisfied. Further, when the charging of the snubber capacitor 33 advances and exceeds the charging voltage of the clamp capacitor 36, the charging of the clamp capacitor 36 is started. At this time, LC resonance occurs in a closed circuit formed by each of the illustrated parasitic inductances, the clamp capacitor 36 and the snubber capacitor 33, and charging and discharging between the clamp capacitor 36 and the snubber capacitor 33 are repeated. At this time, since the fluctuating voltage of the snubber capacitor 33 is also applied to the GTO 31, the maximum applied voltage of the GTO 31 is determined in this LC resonance mode.
The amplitude of the LC resonance greatly depends on the value of the parasitic inductance. In order to suppress the maximum applied voltage of the GTO 31, it is necessary to suppress the value of the parasitic inductance in the closed loop.

In FIG. 21B, since the closed circuit includes the smoothing capacitor 40, the parasitic inductance to be considered increases. The clamp capacitor shown in FIG. 21A needs to be charged to a voltage higher than that of the smoothing capacitor 40, whereas the clamp capacitor shown in FIG. From the viewpoint of mounting including costs, the method shown in FIG. 21B is advantageous. However, since the parasitic inductance tends to be larger than the method of FIG. 21A, it is extremely useful to apply the present invention to such a wiring conductor forming a closed loop.

As described above, the present invention can be applied to a wiring conductor on a closed circuit that does not directly include a semiconductor switching element. In particular, an effect of reducing inductance is exerted on a wiring conductor in which both ends of a connection destination such as a clamp capacitor part are separated and a magnetic flux is canceled by a reciprocating current, that is, a reduction in parasitic inductance cannot be expected. Of course, in the case of a semiconductor switching element used in series multiplexing, when another semiconductor switching element is turned off, a current change occurs and a wiring conductor forming a closed loop that determines a maximum applied voltage of the semiconductor switching element is compared with a wiring conductor. By arranging a conductor having a portion that overlaps and does not overlap with the projection plane in the thickness direction of the substrate, the parasitic inductance on the wiring conductor can be reduced, and as a result, the maximum applied voltage of the semiconductor switching element can be suppressed. Becomes possible. At this time, in order to prevent a residual charge from being generated on the conductor, the wiring conductor may be fixed at at least one point close to the wiring conductor or another potential, and furthermore, an insulator is sandwiched between the wiring conductor and the conductor. Needless to say, this is fine.

Embodiment 12 A twelfth embodiment of the present invention will be described with reference to FIG. FIG. 24 is a configuration diagram of a three-level inverter without an anode reactor, including GTOs 31a to 31d, and snubber diodes 32a, 32a for absorbing a surge voltage.
It comprises a snubber circuit composed of 2d and snubber capacitors 33a, 33d, smoothing capacitors 40a, 40b, and clamp diodes 38a, 38b. In the figure, the free wheel diode is omitted. Although GTO is shown as a semiconductor switching element, any element such as an IGBT may be used as long as di / dt is within the rating in a circuit without an anode reactor.

Wiring inductances 43 a to 4 parasitic on wiring between the smoothing capacitor and the semiconductor switching element
Let L be the value of 3c, and consider the value of L that can be permitted when the semiconductor switching element is turned off. At this time, the capacitance of the snubber capacitor 33a provided in the snubber circuit is set to Cs,
The DC input voltages of the smoothing capacitors 40a and 40b are
dc. Further, the current supplied to the load via the semiconductor switching element is defined as I, and GTO3 as shown in FIG.
Assuming that 1a and 31b are in the on state, when the GTO 31a is turned off, the charging voltage Vcs charged in the snubber capacitor 33a is:

[0069]

(Equation 7)

Can be expressed as follows. This is because the current path immediately after the turn-off is as shown in (2) and the parasitic inductance 43
All the energy of a becomes the charging voltage of the capacitor. Furthermore, as the steady state is approached, energy is stored in the parasitic inductance 43b this time, and this amount is also added to Vcs. Also, this Vcs is GTO31a
Therefore, if the maximum rated voltage of GTO31a is Vmax,

[0071]

(Equation 8)

It is necessary to satisfy the following. Specifically, Vdc = 3000 V, breaking current I = 6000 A,
Assuming that Cs = 3 μF and Vmax = 6000 V, Vcs ≦
In order to satisfy Vmax, L ≦ 0.75 μH. When Vdc is high as described above, the wires of the DC power supply unit cannot be brought close to each other in order to secure an insulation distance. In such a case, if the wiring method of the present invention is used, the inductance can be reduced. Of course, it is needless to say that the present invention can be applied to other multi-level inverters such as a two-level inverter.

According to the present invention, Vdc ≧ 3000V
In addition, when I / Cs is 1000 A / 1 μF or more, that is, when the voltage applied to the semiconductor switching element cannot be suppressed due to the reduction of the wiring inductance, the value of L satisfying (Equation 1) is reduced to below. Wiring inductance can be reduced.

Embodiment 13 A thirteenth embodiment of the present invention will be described with reference to FIG. FIG. 25 is a configuration diagram of a three-level inverter without a snubber circuit, and includes GTOs 31a to 31d and a smoothing capacitor 40.
a, 40b and clamp diodes 38a, 38b. In the figure, the free wheel diode is omitted. GTO is used as a semiconductor switching element.
However, any device such as an IGBT may be used.

Wiring inductances 43a-4 parasitic on wiring between the smoothing capacitor and the semiconductor switching element
Let L be the value of 3c, and consider an allowable value of L when the semiconductor switching element is turned off. At this time, the DC input voltages of the smoothing capacitors 40a and 40b are respectively set to Vd
c, and the maximum slope of the current falling rate when the semiconductor switching element is turned off is represented by di / dt.
Assuming that the GTOs 31a and 31b are on as in (1), when the GTO 31a is turned off, the snubber capacitor 3
Assuming that the maximum value of the voltage applied to 3a is Vmax,

[0076]

(Equation 9)

It is necessary to satisfy the following. In this case as well, FIG.
Similarly to the above, after the GTO 31a is turned off, the energy is stored in the parasitic inductance 43b, and the voltage corresponding to this is also applied to the semiconductor switching element. Specifically, Vd
c = 3000 V, di / dt = 3 × 10 ¹⁰ A / s, Vma
Assuming that x = 6000 V, in order to keep the voltage applied to the semiconductor switching element below Vmax, L ≦ 0.5 μ
H. Such a drastic reduction in inductance can be realized by using the wiring method of the present invention in addition to the wiring method in which the reciprocating conductors are brought close to each other. Of course 2
The present invention is also applicable to other multi-level inverters including a level inverter.

According to the present invention, Vdc ≧ 3000V
In addition, when I / Cs is 1000 A / 1 μF or more, that is, when the voltage applied to the semiconductor switching element cannot be suppressed due to the reduction in the wiring inductance, the wiring inductance is adjusted to satisfy (Equation 2). Can be smaller.

[0079]

According to the present invention, the wiring inductance can be reduced, and the surge voltage at the time of turning off the self-extinguishing type semiconductor element can be suppressed. Therefore, the capacitance of the capacitor can be reduced, and the loss can be reduced. In addition, since the magnetic flux is canceled by the induced current, there is a shielding effect, and the leakage of the magnetic flux to the periphery can be reduced.

[Brief description of the drawings]

FIG. 1 shows a wiring conductor of a power converter according to a first embodiment of the present invention.

FIG. 2 is a structural model in which a second conductor is arranged close to a first conductor.

FIG. 3 is a diagram illustrating an inductance characteristic depending on a distance between a first conductor and a second conductor.

FIG. 4 shows a wiring conductor of a power converter according to a second embodiment of the present invention.

FIG. 5 is a structural model in which a second conductor is arranged close to a first conductor.

FIG. 6 is a diagram showing inductance characteristics according to a method of arranging a first conductor and a second conductor.

FIG. 7 shows a wiring conductor of a power converter according to a third embodiment of the present invention.

FIG. 8 is a diagram illustrating inductance characteristics according to a method of arranging a first conductor and a second conductor.

FIG. 9 shows a wiring conductor of a power converter according to a fourth embodiment of the present invention.

FIG. 10 is a layout diagram of wiring conductors in which a second conductor having a slit is provided near a first conductor.

FIG. 11 is a diagram showing a relationship between a second conductor thickness and inductance.

FIG. 12 is a diagram illustrating frequency characteristics of inductance according to a method of arranging a first conductor and a second conductor.

FIG. 13 shows a wiring conductor of a power converter according to a fifth embodiment of the present invention.

FIG. 14 shows a wiring conductor of a power converter according to a sixth embodiment of the present invention.

FIG. 15 shows a wiring conductor of a power converter according to a seventh embodiment of the present invention.

FIG. 16 is a wiring conductor mounting diagram showing a method of fixing the first conductor and the second conductor.

FIG. 17 shows a wiring conductor of a power converter according to an eighth embodiment of the present invention.

FIG. 18 shows a wiring conductor of a power converter according to a ninth embodiment of the present invention.

FIG. 19 is a mounting diagram of a snubber circuit according to a tenth embodiment of the present invention.

FIG. 20 is a mounting side view of a clamp circuit according to an eleventh embodiment of the present invention.

FIG. 21 is a circuit diagram showing a wiring portion where a current change occurs when a semiconductor switching element is turned off.

FIG. 22 is a diagram illustrating a configuration example of a conventional power converter.

FIG. 23 is a diagram illustrating the operation of a conventional snubber circuit and a clamp circuit applied to a self-extinguishing type semiconductor element.

FIG. 24 is a diagram illustrating a circuit operation including a snubber circuit at the time of turning off a self-extinguishing type semiconductor element that does not require an anode reactor.

FIG. 25 is a diagram illustrating a circuit operation at the time of turning off a self-extinguishing type semiconductor element that does not require a snubber circuit.

FIG. 26 is a diagram showing a conventional wiring mounting for reducing inductance.

[Explanation of symbols]

1, 11, 12 ... first conductor, 2, 21, 22, ... second conductor, 3 ... insulator, 4 ... insulating material, 5 ... conductive screw, 6 ...
Insulating screw, 7 ... spacer, 8 ... insulating spacer, 3
1, 31a to 31d ... GTO, 32, 32a, 32d ...
Snubber diodes, 33, 33a, 33d: snubber capacitors, 34: parasitic inductance in snubber circuits, 35
... diode, 36 ... clamp capacitor, 37 ... parasitic inductance in the clamp circuit, 38, 38a, 38b
... clamp diode, 39 ... cooling fin, 40, 40
a, 40b: smoothing capacitor; 41, parasitic inductance in the smoothing circuit; 42, parasitic inductance in the clamp diode portion; 43a to 43c; ... Current direction (from front side to back side of paper), 101 AC power supply, 102 converter (1
Phase), 103: smoothing capacitor, 104: inverter (for one phase), 105: AC motor.

Claims (25)

[Claims] 1. A power converter for controlling a load current by a semiconductor switching element, wherein the power converter is connected to the first conductor in a vicinity of a first conductor in which a current change occurs due to a control for turning on or off the semiconductor switching element. A power converter comprising: a wiring that closely arranges a second conductor that generates an induced current in response to a current change. 2. A power converter for controlling a load current by using a semiconductor switching element, wherein the power supply includes: A power converter, wherein a second conductor that generates an induced current according to a current change is arranged, and the first conductor and the second conductor are electrically connected at at least one point. 3. A power converter for controlling a load current by a semiconductor switching element, wherein a second conductor is arranged in proximity to the first conductor which causes a change in current due to control of energizing or deactivating the semiconductor switching element. And a power converter, wherein the first conductor and the second conductor are electrically connected at at least one point. A converter for converting an alternating current into a direct current, the converter including a first semiconductor switching element, a smoothing capacitor for smoothing the direct current, and a reverse conversion of the direct current smoothed by the smoothing capacitor into an alternating current. A power converter having an inverter unit provided with a second semiconductor switching element, a part of a wide first conductor connecting the smoothing capacitor and the converter unit or the inverter unit directly or via another member. Or in the entire section, a second conductor having a portion that at least partially overlaps and does not overlap at least partially with a projection surface of the first conductor with respect to the plate thickness direction is arranged close to the first conductor, A power converter, wherein at least one point of the second conductor is electrically connected to the first conductor. 5. A converter unit having a first semiconductor switching element for converting AC to DC, a smoothing capacitor for smoothing the DC, and a DC for inversely converting the DC smoothed by the smoothing capacitor to AC. A power converter having an inverter unit having two semiconductor switching elements, wherein a part of a wide first conductor that connects the smoothing capacitor and the converter unit or the inverter unit directly or via another member or In the entire section, the second conductor having the same width as the first conductor is moved from 10% to 60% with respect to the projection plane in the thickness direction of the first conductor and the width of the first conductor.
%, Wherein at least one point of the second conductor is electrically connected to the first conductor so as to overlap in the range of%. 6. A converter unit having a first semiconductor switching element for converting AC to DC, a smoothing capacitor for smoothing the DC, and a DC for smoothing the DC smoothed by the smoothing capacitor is converted back to AC. A power converter having an inverter unit provided with a second semiconductor switching element, wherein the smoothing capacitor and the converter unit or the inverter unit are connected directly or via another member, and currents flow in opposite directions to generate a magnetic flux with each other. In a part or the whole section of the two wide first conductors arranged in parallel so as to cancel each other, at least partly overlap and at least partly overlap with the projection surface of the first conductor in the thickness direction. At least one second conductor having a portion not to be disposed is disposed in close proximity to the first conductor, and at least one point of the second conductor is connected to the second conductor. A power converter characterized by being electrically connected to one of the conductors. 7. A converter provided with a first semiconductor switching element for converting an alternating current into a direct current, a smoothing capacitor for smoothing the direct current, and an inverse converter for converting the direct current smoothed by the smoothing capacitor into an alternating current. A power converter having an inverter unit provided with two semiconductor switching elements, wherein at the time of turn-on or turn-off of the semiconductor switching elements, at least a part of or a whole section of the wide first conductor that causes a current change. A second conductor having a portion that at least partially overlaps and at least partially does not overlap with the projection plane of the conductor in the plate thickness direction,
A power converter, wherein at least one point of the second conductor is electrically connected to the first conductor. 8. A cutoff current I of a semiconductor switching element having a DC input voltage Vdc of 3 kV or more and a rated voltage Vmax.
The ratio Is / Cs of s to the snubber capacitor capacitance Cs for absorbing the surge voltage of the semiconductor switching element is 1 kA.
The power converter according to any one of claims 1 to 7, wherein a ratio of a wiring inductance L between a DC power supply and the semiconductor switching element and a capacitance of the snubber capacitor Cs is: ] Power converter that satisfies the requirements. 9. The semiconductor device according to claim 1, further comprising a semiconductor switching element having a maximum slope of a rated voltage Vmax and a current decreasing rate at the time of cutoff of di / dt, and a DC input voltage Vdc of 3 kV or more. 3. The power converter according to claim 1, wherein the wiring inductance L between the DC power supply and the semiconductor switching element is Power converter that satisfies the requirements. 10. The power converter according to claim 1, wherein a shortest distance between the second conductor and the first conductor is 3 mm or less. 11. A width of the first conductor, which overlaps with the second conductor on a projection plane in a thickness direction of the first conductor, is one of the width of the first conductor.
It is 0% or more, Claims 1-4 and 6- characterized by the above-mentioned.
The power converter according to claim 10. 12. The method according to claim 1, wherein a width of the first conductor not overlapping with the second conductor on a projection plane in a plate thickness direction is equal to or more than の of the width of the first conductor. 11
The power converter according to claim 1. 13. The power converter according to claim 1, wherein the second conductor has a thickness of 1 mm or more. 14. The apparatus according to claim 1, wherein a thickness of said second conductor is smaller than a thickness of said first conductor.
The power converter according to claim 1. 15. The second conductor has a portion that at least partially overlaps with a projection plane of the first conductor in a plate thickness direction and at least one end of the first conductor with respect to a plate width direction. The power converter according to any one of claims 1 to 14, wherein the portion is bent. 16. The power converter according to claim 1, wherein at least one slit is provided in the second conductor according to any one of claims 1 to 15. 17. The apparatus according to claim 1, wherein said second conductor and said first conductor are fixed via an insulator.
The power converter according to claim 1. 18. The power converter according to claim 17, wherein the second conductor and the first conductor are fixed by using both conductive connecting means and insulating connecting means. vessel. 19. A ratio Is / Cs of a cut-off current Is of a semiconductor switching element having a DC input voltage Vdc of 3 kV or more and a rated voltage Vmax to a snubber capacitor capacitance Cs for absorbing a surge voltage of the semiconductor switching element is 1 k.
In a power converter of A / 1 μF or more, the ratio between the wiring inductance L between the DC power supply and the semiconductor switching element and the snubber capacitor capacitance Cs is Power converter that satisfies the requirements. 20. A power converter comprising a semiconductor switching element having a maximum slope of a rated voltage Vmax and a current falling rate at cutoff of di / dt and a DC input voltage Vdc of 3 kV or more, wherein a DC power supply and said semiconductor The wiring inductance L between the switching element and Power converter that satisfies the requirements. 21. An electric device for controlling a load current by a semiconductor switching element, wherein the current flowing through the first conductor is close to the first conductor which causes a current change due to the control of energizing or deactivating the semiconductor switching element. An electric device comprising: a second conductor that generates an induced current in accordance with a change; and an electrical connection between the first conductor and the second conductor at at least one point. 22. A width of the first conductor, which overlaps with the second conductor on a projection plane in a plate thickness direction, is one of the first conductor width.
The electric device according to claim 21, wherein the electric device is 0% or more. 23. The electric device according to claim 21, wherein the second conductor and the first conductor are fixed via an insulator. 24. The electric device according to claim 21, wherein said second conductor and said first conductor are fixed via an insulator. 25. A converter comprising a first semiconductor switching element for converting AC into DC, a smoothing capacitor for smoothing the DC, and a DC which is inversely converted from the DC smoothed by the smoothing capacitor into AC. In a method for manufacturing a power converter having an inverter unit provided with two semiconductor switching elements, a part or all of a wide first conductor connecting circuit components is arranged in a thickness direction of the first conductor. A second conductor having a portion at least partially overlapping and at least partially non-overlapping on a projection surface with respect to the first conductor and the second conductor, A method for manufacturing a power converter, comprising: