JP2004165309A - Capacitor unit and semiconductor power converter having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacitor unit which can reduce the variations in wiring inductance of each capacitor without increasing the size. <P>SOLUTION: As shown in the figure, the capacitors 11-13 are so arranged that the polarity of only the capacitor 11 may be opposite to that of the other two capacitors. An anode terminal (only one terminal 11a is visible in the figure) of each capacitor is connected to an anode-side conductor 2 of a wiring board 6, while cathode terminals 11b-13b are connected to a cathode-side conductor 3 through the anode-side conductor 2. The anode-side and cathode-side conductors 2 and 3 are provided with anode-side and cathode-side external terminals 2a and 3b, respectively. Since the anode terminal 11a of the hithermost capacitor 11 is connected to the anode-side conductor 2 at the nearest position to the cathode-side external terminal 3b, and the cathode terminal 11b is connected to the cathode-side conductor 3 at the nearest position to the anode-side external terminal 2a; variations in wiring inductance of the capacitors 11-13 can be reduced without increasing the size of the capacitor unit. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a capacitor unit in which a plurality of capacitors are connected in parallel by connection conductors, and more particularly to a capacitor unit capable of reducing variation in wiring inductance of each capacitor and a semiconductor power conversion device having this capacitor unit.
[0002]
[Prior art]
For example, a smoothing capacitor unit used in a semiconductor power conversion device needs to have a low high-frequency impedance in order to reduce heat generation of the capacitor due to ripple current and reduce switching surge voltage. The following is known as a device for realizing such a low-impedance capacitor unit. That is, the lead terminals of the same polarity of the plurality of parallel capacitors are respectively connected to the one metal plate and the other metal plate to form a capacitor unit.
[0003]
Each metal plate has a shape such that one rectangular conductive plate, which is larger than the area where the capacitor is disposed, is divided into left and right by providing a thin slit in the center, and one and the other are formed. You are. A plurality of capacitors were arranged in parallel in the length (depth) direction of the metal plate, and the lead terminal of one pole of the capacitor was connected to one metal plate, and the lead terminal of the other pole was connected to the other metal plate. Things.
[0004]
In the metal plate, the ratio R = W / L of the length L in the direction in which the capacitors are arranged in parallel and the lead terminals of the same polarity are connected to the width W in the connection direction is made as wide as 1/4 or more. As a result, the current flowing through each capacitor can be made uniform, so that not only can the resulting allowable current of the entire capacitor unit be increased, but also its high-frequency impedance can be reduced. (For example, see Patent Document 1).
[0005]
[Patent Document 1]
JP 2000-286150 A (paragraph numbers 0015 and 0018 and FIG. 1)
[0006]
[Problems to be solved by the invention]
Since the conventional capacitor unit is configured as described above, it is necessary to increase the width W of the metal plate, so that the capacitor unit becomes large. Further, since the width W of the metal plate is increased, the wiring inductance increases, and there is a problem that the surge voltage generated when the semiconductor switching element switches is increased.
An object of the present invention is to solve the above-mentioned problems and to obtain a capacitor unit capable of reducing variation in wiring inductance of a capacitor without increasing the size, and a power semiconductor conversion device using the capacitor unit. And
[0007]
[Means for Solving the Problems]
The capacitor unit according to the present invention includes a plurality of capacitors and a connecting member, wherein the capacitor has a positive terminal connected to the positive electrode of the DC circuit and a negative terminal connected to the negative electrode of the DC circuit. The plurality of capacitors are arranged so that the capacitor terminal arrangement directions from the positive terminal to the negative terminal of each capacitor are parallel to each other, and at least one of the plurality of capacitors has the capacitor terminal arrangement direction of another capacitor. The connection member has a positive-side conductive member that connects the positive terminals of the plurality of capacitors and a negative-side conductive member that connects the negative terminals of the plurality of capacitors. It is.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
1 to 6 show an embodiment of the present invention. FIG. 1 is an exploded perspective view showing a configuration of a capacitor unit, and FIG. 2 is a plan view. FIG. 3 is an explanatory diagram showing a position when one capacitor is provided on the wiring board, and FIG. 4 is an explanatory diagram showing a relationship between distances from the positive and negative external terminals to the connection position of the capacitor and a wiring inductance. . FIG. 5 is a plan view showing an arrangement in which all parallel capacitors are connected in the same polarity arrangement. FIG. 6 shows a case where all the parallel capacitors are connected in the same polarity arrangement, a case where the capacitors arranged closest to the positive and negative external terminals are connected in reverse polarity, and the other capacitors are connected in the same polarity, It is explanatory drawing which shows the wiring inductance of the capacitor of each position.
[0009]
First, for convenience of explanation, in the drawings of the present invention, unless otherwise required, in the perspective view, the axes of the x-y-z three-axis orthogonal coordinate system are set to the x-axis from left to right in the drawing. , The y-axis is defined in the depth direction from the near side, and the z-axis is defined in the upward direction from the bottom. In the plan view, the x-axis is defined from left to right in the figure, and the y-axis is defined from top to bottom.
[0010]
1 and 2, the capacitor group 1 includes three capacitors 11 to 13 arranged at equal intervals in the y-axis direction as shown in FIG. The foremost capacitor 11 in FIG. 1 has a positive terminal 11a located on the right side and a negative terminal 11b located on the left, and the terminal arrangement direction from the positive terminal to the negative terminal is parallel to the x-axis. It is arranged so that the direction is opposite to the x-axis. In the second and third capacitors 12 and 13, the respective positive terminals (12a, 13a), which cannot be seen in the drawing, are located on the left, and the respective negative terminals 12b, 13b are located on the right. They are arranged so as to face right and in the same direction as the x-axis. In this embodiment, the capacitors 11 to 13 are film capacitors.
[0011]
A wiring board 6 is provided below the capacitor group 1. The wiring board 6 has the positive-side conductor 2 and the negative-side conductor 3 formed of a thin copper conductor (not shown in detail) opposed to each other in the z-axis direction via a substrate (not shown) made of an insulator. Together with the substrate to be integrated. Although not shown, the surfaces of the positive-electrode-side conductor 2 and the negative-electrode-side conductor 3 are treated with an insulating coating for protection. When the current capacity is small, the same one as a normal printed wiring board may be used.
[0012]
A small rectangular positive external terminal 2a and a negative external terminal 3b are provided on the positive conductor 2 and the negative conductor 3 at a predetermined distance in the x-axis direction. It is provided so as to be electrically connected integrally with the conductor 3. The positive and negative external terminals 2a and 3b are external terminals of the capacitor unit. The through-holes in the z-axis direction as shown in FIG. 1 are provided in the positive and negative side conductors 2 and 3, and the capacitors 11 to 13 are arranged as shown in FIG. The positive electrode terminal (only 11 a is visible in FIG. 1) is connected to the positive electrode conductor 2, and each negative electrode terminal 11 b to 13 b of the capacitor 11 is provided with a predetermined gap with the positive electrode conductor 2 to connect the positive electrode conductor 2. It penetrates and is connected to the negative electrode side conductor 3.
[0013]
As described above, the capacitor 11 is arranged with its terminal arrangement direction reversed with respect to the external terminal arrangement direction which is the direction from the positive external terminal 2a to the negative external terminal 3b, that is, the direction of the x-axis. The capacitors 12 and 13 are connected by aligning their terminal arrangement directions along the x-axis (hereinafter, referred to as same-polarity connection).
[0014]
As a result, it is possible to equalize the wiring inductance of each of the capacitors 11 to 13 without increasing the size of the capacitor unit and increasing the wiring impedance. Therefore, the ripple currents of the capacitors 11 to 13 can be equalized, and the ripple current tolerance of the entire capacitor unit can be increased.
[0015]
Hereinafter, the reason why the wiring inductances of the capacitors 11 to 13 can be equalized without increasing the size of the capacitor unit will be described with reference to FIGS. As shown in FIG. 3A, one capacitor 11 is prepared, and the distance d in the y-axis direction from the end of the wiring board 6 is sequentially changed from the position P1, which is D1, D2, and D3, to P3. And connected to the wiring board 6. At this time, the wiring inductance of the capacitor 11 viewed from the positive and negative external terminals 2a and 3b is as shown by a curve A in FIG. That is, the wiring inductances at the positions P1 to P3 and at the positions P4 to P6 not shown in FIGS. 1 and 2 are indicated by points A1 to A6 on the curve A with the distance d as the horizontal axis.
[0016]
Further, it is assumed that the capacitors 11 are connected in reverse polarity by changing the positions from the positions P1 to P6 as shown in FIG. At this time, the wiring inductance of the capacitor 11 at each of the positions P1 to P6 viewed from the positive and negative external terminals 2a and 3b is points B1 to B6 on the curve B in FIG. However, FIG. 4 shows the wiring inductance when only one capacitor is connected to the wiring board 6, and the mutual inductance between the capacitors when a plurality of capacitors are connected (described later) is not considered.
[0017]
As shown in FIG. 4, in both the same-polarity connection and the opposite-polarity connection, the wiring inductance increases as the distance d increases, except for a part (point B2 at the position P2). The same-polarity connection (curve A) has a smaller wiring inductance than the reverse-polarity connection (curve B), and the shorter the distance d from the positive and negative external terminals 2a and 3b, the smaller the ratio. The capacitor 11 closest to the negative and negative external terminals 2a and 3b is most noticeable. For example, in the case of the same polarity connection, the difference between the wiring inductance between the case where the capacitor 11 is placed at the foremost position P1 and the case where the capacitor 11 is placed at the third position P3 is the width H shown in FIG. Become.
[0018]
Next, six capacitors 11 to 16 are prepared (only three capacitors 11 to 13 are shown in the figure, but there are a total of six capacitors). When all the capacitors 11 to 16 are connected in parallel with the same polarity connection, Sixteen wiring inductances are shown by points F1 to F6 on the curve F in FIG. 6 with the horizontal axis representing the distance d in the y-axis direction from the end of the wiring board 6. If all capacitors are connected in the same polarity as described above, high-frequency ripple current is concentrated on the capacitor 11 due to variation (non-uniformity) of the wiring inductance (strictly, the inductance of the capacitor including the wiring inductance). The ripple current resistance of the unit is reduced.
[0019]
In addition, when a pulse-like current flows through the capacitor due to a variation in the wiring inductance, an unnecessary oscillating current is generated between the capacitors, thereby further reducing the allowable ripple current of the capacitor unit. For this reason, particularly in a capacitor unit used in a semiconductor power conversion device, it is important to reduce the unevenness of the wiring inductance of each capacitor and equalize the ripple current.
[0020]
It is possible to equalize the wiring inductance by lengthening the positive and negative conductors 2 and 3 and keeping the connection points of the capacitors 11 to 13 away from the positive and negative external terminals 2a and 3b. Since the positive and negative conductors 2 and 3 become long, the capacitor unit becomes large. In addition, the wiring inductance increases, and when used in a semiconductor power conversion device, the surge voltage generated when the semiconductor switching element performs switching increases.
[0021]
Next, a case where the capacitors 11 arranged closest to the positive and negative external terminals 2a and 3b are connected in reverse polarity, and the other capacitors 12 to 16 (14 to 16 are not shown) are connected in the same polarity. The wiring inductance is shown by points G1 to G6 on the curve G in FIG. As is clear from FIG. 6, the variation in the wiring inductance of each of the capacitors 11 to 16 is reduced as compared with the case of the same polarity connection (points F1 to F6 on the curve F). Further, since there is no capacitor with extremely small wiring inductance, the concentration of ripple current on a specific capacitor is reduced, and the allowable ripple current of the capacitor unit increases.
[0022]
By the way, when a plurality of capacitors are connected in the same polarity (characteristic curve F), the mutual inductance with the adjacently arranged capacitors is all positive, and when one capacitor shown in FIG. 4 is connected (characteristic curve A). 6, the wiring inductance of each of the capacitors 11 to 16 becomes as shown by points F1 to F6 in FIG. When the foremost capacitor 11 is connected in reverse polarity and the other capacitors 12 to 16 are connected in reverse polarity, the mutual inductance between the capacitor 11 and the other capacitors 12 to 16 becomes negative, and Mutual inductance is positive.
[0023]
As a result, the wiring inductance of each of the capacitors 11 to 16 becomes as shown by points G1 to G6 in FIG. 6, and the wiring inductance shown by points G2 and G3 is smaller than the wiring inductance shown by points F2 and F3. It becomes. The effect increases as the capacitor is closer to the capacitor 11 (points G2 and G3), and hardly occurs when the distance to the capacitors 15 and 16 (points G5 and G6) increases.
Although the case where six capacitors are connected has been described above, the case where three capacitors are connected as shown in FIG. 2 also has substantially the same characteristics as the case shown in FIG. The wiring inductance of each of the capacitors 11 to 13 in the case of a simple connection has substantially the same value as the points G1 to G3 shown in FIG.
[0024]
In this embodiment, only the capacitor 11 of the three capacitors is connected in reverse polarity. However, by connecting the capacitor 12 in reverse polarity, the wiring inductance of each capacitor can be made more uniform. However, since the wiring inductance increases by connecting the capacitor 12 in the reverse polarity, the wiring inductance of the entire capacitor unit slightly increases.
As described above, according to this embodiment, each of the capacitors viewed from the positive and negative external terminals 2a and 3b without increasing the size of the capacitor unit and while suppressing an increase in wiring inductance. The variation (difference) in the wiring inductance can be reduced, and the ripple currents of the capacitors connected in parallel can be equalized.
[0025]
Embodiment 2 FIG.
FIG. 7 is a plan view showing a configuration of a capacitor unit according to another embodiment of the present invention. In FIG. 7, the capacitor unit includes six capacitors 11 to 13 and 21 to 23 connected in parallel. The three front capacitors 11 to 13 are arranged at equal intervals on one straight line parallel to the x-axis, and the three capacitors 21 to 23 in the second row are spaced apart from the capacitors 11 to 13 in the y-axis direction. And are arranged on the wiring board 6 at equal intervals on another straight line parallel to the x-axis. The capacitor 12 disposed closest to the positive and negative external terminals 2a and 3b is connected in reverse polarity to the positive and negative external terminals 2a and 3b, and the other five capacitors are connected in the same polarity. Have been. Other configurations are the same as those in the first embodiment shown in FIG. 1, and the corresponding components are denoted by the same reference numerals and description thereof is omitted. As a result, the variation in the wiring inductance of each capacitor is reduced, and the ripple current is equalized.
[0026]
Embodiment 3 FIG.
8 and 9 show still another embodiment of the present invention. FIG. 8 is a plan view showing the structure of a capacitor unit, and FIG. 9 is an explanation for explaining the reason why the wiring inductance is reduced. FIG. In FIG. 8, the capacitor unit includes four capacitors 11 to 14 arranged on the wiring board 6 at predetermined intervals in the wiring length direction (y-axis direction) of the positive conductor 2 and the negative conductor 3, They are connected in parallel. The capacitor 11 disposed closest to the positive and negative external terminals 2a, 3b and the capacitor 13 disposed third from the positive and negative external terminals 2a, 3b are connected in reverse polarity. The capacitors 12 and 14 are connected in the same polarity.
[0027]
In this way, by alternately arranging the capacitors 11 to 14 so as to have the same polarity connection and the opposite polarity connection, the current components flowing in the capacitor and the positive and negative terminals of the capacitor as shown by arrows in FIG. Is in the opposite direction to the adjacent capacitor. Therefore, the magnetic fields generated by these current components cancel each other, and the wiring inductance around the capacitor is reduced. Further, since the current components flowing into and out of the capacitor to the positive conductor 2 and the negative conductor 3 are dispersed at both ends, the wiring inductance between the positive conductor 2 and the negative conductor 3 is also reduced.
[0028]
As described above, by connecting adjacent capacitors alternately with their polarities inverted, in addition to reducing the variation in wiring inductance, it is possible to reduce the wiring inductance of the entire capacitor unit and reduce the switching surge voltage. Can be reduced.
[0029]
Embodiment 4 FIG.
FIG. 10 is a plan view showing a configuration of a capacitor unit according to another embodiment of the present invention. 10, in the capacitor unit, four capacitors 11 to 14 are arranged at equal intervals in the x-axis direction, supported by the wiring board 6, and connected in parallel. Here, the capacitor 12 disposed closest to the positive external terminal 2a has a negative polarity on the terminal closer to the positive external terminal 2a, and the capacitor 13 disposed closest to the negative external terminal 3b has a negative polarity. The polarity of the terminal closer to the side external terminal 3b is positive, and the terminals of the capacitors 12 and 13 disposed closest to the positive side external terminal 2a and the negative side external terminal 3b are arranged so as to have different polarities.
[0030]
With such a configuration, the variation in the wiring inductance of each of the capacitors 11 to 14 is reduced, and the ripple current is equalized. Further, since the polarity connection between the adjacent capacitors is inverted, the mutual inductance between the adjacent capacitors becomes negative, and the wiring inductance of the entire capacitor unit can be reduced.
[0031]
Embodiment 5 FIG.
FIG. 11 is a plan view showing a configuration of a capacitor unit according to another embodiment of the present invention. In FIG. 11, the capacitor unit is configured such that four capacitors 11, 12, 21, 22 are supported by the wiring board 6 and connected in parallel. The two capacitors 11 and 12 in the foreground are equally spaced on one straight line parallel to the x axis, and the two capacitors 21 and 22 in the second row are spaced apart from the capacitors 11 and 12 in the y axis direction by x They are arranged on the wiring board 6 at equal intervals on another straight line parallel to the axis. The capacitors 11 and 12 in the first row, which are arranged closest to the positive external terminal 2a and the negative external terminal 3b of the wiring board 6, have the terminal arrangement directions of the external terminals of the positive and negative external terminals 2a and 3b. The negative terminal of the capacitor 11 is connected to the negative conductor (not shown in FIG. 11) in the same direction as the arrangement direction and the negative terminal of the capacitor 11 is closer to the positive external terminal 2a than the positive terminal. It is connected to the positive electrode side conductor (not visible in FIG. 11) so as to be closer to the negative electrode side external terminal 3b than the negative electrode terminal.
[0032]
The same applies to the capacitors 21 and 22 in the second row. The terminal arrangement direction is the same as the external terminal arrangement direction of the positive and negative external terminals 2a and 3b (same as the direction of the x-axis). The negative terminal 21 is connected to the negative conductor (not shown in FIG. 11) so that the negative terminal is closer to the positive external terminal 2a than the positive terminal, and the positive terminal of the capacitor 22 is connected to the negative external terminal than the negative terminal. 3b and connected to the positive conductor (not visible in FIG. 11).
As a result, the variation in the wiring inductance of each capacitor is reduced, and the ripple current is equalized.
[0033]
Embodiment 6 FIG.
12 and 13 show still another embodiment of the present invention. FIG. 13 is a plan view showing a configuration of a semiconductor power converter, and FIG. 13 is a circuit diagram of the semiconductor power converter. 12, the capacitor unit 10 is configured such that eight capacitors 11 to 18 are connected in parallel on a wiring board 46 in a polarity arrangement as shown in FIG. That is, the four front capacitors 11 to 14 are arranged at equal intervals on one straight line parallel to the x-axis, and the four capacitors 21 to 24 in the second row are spaced apart from the capacitors 11 to 14 in the y-axis direction. Are arranged at equal intervals on another straight line parallel to the x-axis. The capacitors 11 to 14 in the first column are connected in reverse polarity connection, forward polarity connection, forward polarity connection, and reverse polarity connection from the left, and the capacitors 21 to 24 in the second column are all forward polarity connected.
[0034]
The positive-electrode-side external terminals 21 a, 22 a, and 23 a are provided integrally with the positive-electrode-side conductor 2 on the positive-electrode-side conductor 2 of the wiring board 46. Further, the negative electrode side conductor 3 is provided with the negative electrode side external terminals 31b, 32b, 33b integrally with the negative electrode side conductor 3. The positive and negative external terminals 21a and 31b are paired with the positive and negative external terminals 22a and 32b, and the positive and negative external terminals 23a and 33b are paired with each other. They are arranged at predetermined intervals in the direction. The capacitor unit 10 includes a U-phase arm 41 of the three-phase inverter 4 via positive and negative external terminals 21a and 31b, and a V-phase arm 42 via positive and negative external terminals 22a and 32b. The W-phase arm 43 is connected via positive and negative external terminals 23a and 33b.
[0035]
Further, any one of the positive and negative external terminals 21a, 22a, 32a, 31b, 32b, and 33b of the positive and negative external terminals 21a, 22b, and 33b of the wiring board 46, or the positive terminal (not shown in FIG. 12). A DC power supply 5 is connected to the positive and negative external terminals separately provided on the negative conductors 2 and 3, and the semiconductor switching elements provided on the arms 41 to 43 perform opening and closing operations to generate DC power. The power is converted into AC power and output from the three-phase AC terminals U, V, W (see the circuit diagram of FIG. 13). In FIG. 12, an IGBT (Insulated Gate Bipolar Transistor) is used as the semiconductor switching element, but it may be a MOSFET, a GTO, or the like.
[0036]
During the operation of the three-phase inverter, current is supplied from the capacitor unit 10 when the IGBTs of the arms 41 to 43 open and close. For example, when the U-phase IGBT is switched to supply current from the capacitor unit 10, the current is supplied from each of the capacitors 11 to 14, 21 to 24 according to the impedance ratio viewed from the positive and negative external terminals 21a and 31b. Current ratio is determined.
[0037]
Similarly, when the V-phase IGBT is switched and current is supplied from the capacitor unit 10, the current ratio supplied from each capacitor is determined by the impedance ratio as viewed from the positive and negative external terminals 22a and 32b. Thus, when there are a plurality of positive and negative external terminals, in order to equalize the ripple current of the capacitor, it is necessary to equalize the impedance of the capacitor as viewed from each of the positive and negative external terminals. .
[0038]
In this embodiment, the capacitor 11 disposed closest to the positive and negative external terminals 21 a and 31 b connected to the U-phase arm 41, and the positive and negative external terminals 23 a connected to the W-phase arm 43 , 33b are connected in reverse polarity, and the other six capacitors are connected in the same polarity, thereby equalizing the wiring impedance of each capacitor.
[0039]
The reason why the capacitor 11 is connected in reverse polarity to the positive and negative external terminals 21a and 31b and the capacitor 14 is connected in reverse polarity to the positive and negative external terminals 23a and 33b will be described. The wiring distance from the positive and negative external terminals 21a, 31b connected to the U-phase arm to each capacitor is as follows: capacitor 11 <capacitor 21 <capacitor 12 <capacitor 22 <capacitor 13 <capacitor 23 <capacitor 14 <capacitor 24> capacitor 24 Become.
[0040]
When all the capacitors 11 to 14 and 21 to 24 are connected in the same polarity, the wiring inductance to each capacitor is determined from FIG. 6 as follows: capacitor 11 << capacitor 21 <capacitor 12 ≒ capacitor 22 <capacitor 13 ≒ capacitor 23 <capacitor 14 ≒ capacitor As a result, the high-frequency ripple current concentrates on the capacitor 12. By connecting the capacitors 11 in reverse polarity, the wiring inductance of each capacitor viewed from the U-phase arm is equalized, and the high-frequency ripple current can be equalized.
[0041]
The same applies to the W-phase, and by connecting the capacitors 14 in reverse polarity, it is possible to equalize the wiring inductance of each capacitor as viewed from the W-phase arm. The capacitors near the positive and negative external terminals 21a and 31b and the positive and negative external terminals 23a and 33b connected to the U-phase and V-phase arms are the same as those shown in FIG. The capacitors 11 and 14 are connected in reverse polarity to the positive and negative external terminals 21a and 31b and the positive and negative external terminals 23a and 33b, respectively. From the viewpoint of the phase arm, it can be said that the embodiment shown in FIG. 2 is applied.
[0042]
In the V-phase arm, the wiring distance from the positive and negative external terminals 22a and 32b connected to the V-phase arm to each capacitor is as follows: capacitor 12 = capacitor 13 <capacitor 22 = capacitor 23 <capacitor 11 = capacitor 14 <capacitor 21 = capacitor 24, and the two capacitors closest to each other are the capacitor 12 and the capacitor 13. In this portion, the negative terminal of the capacitor 12 is connected to the negative conductor 3 at a position closest to the positive external terminal 22a, and the positive terminal of the capacitor 13 is connected to the positive conductor 2 at a position closest to the negative external terminal 32b. Looking at this portion, the arrangement is the same as that shown in FIG. 11, and it can be said that the embodiment shown in FIG. 11 is applied.
[0043]
Thereby, the concentration of the ripple current is dispersed. Since the wiring distance from the V-phase arm 42 to the capacitors 12 and 13 is longer than the wiring distance to the capacitor 11 as viewed from the U-phase arm 41, the ripple current concentration on the capacitors 12 and 13 is reduced. You. For the above reason, even if the capacitors 12 and 13 are connected in the same polarity, the degree of concentration of the ripple current is small.
[0044]
As described above, according to this embodiment, by equalizing the wiring inductance of the capacitors as viewed from each arm of the three-phase inverter, the size of each capacitor connected in parallel can be reduced without increasing the size of the capacitor unit. The ripple current can be equalized. Therefore, the size and weight of the semiconductor power converter can be reduced.
[0045]
In each of the above embodiments, the positive and negative conductors opposing each other in the form of a rectangular flat plate are shown. However, the present invention is not impaired without being limited to such shapes and opposing relationships. Others can be used within the scope. In the above embodiments, the capacitor is a film capacitor.However, the capacitor may be an electrolytic capacitor or another capacitor, and the capacitor is not limited to a square shape, but may be a cylindrical shape, an oval shape, or another shape. However, the same effect can be obtained.
[0046]
【The invention's effect】
As described above, the present invention has a plurality of capacitors and a connecting member, and the capacitor has a positive terminal connected to the positive electrode of the DC circuit and a negative terminal connected to the negative electrode of the DC circuit. The plurality of capacitors are arranged so that the capacitor terminal arrangement directions from the positive terminal to the negative terminal of each capacitor are parallel to each other, and at least one of the plurality of capacitors has the capacitor terminal arrangement direction of another capacitor. The connection members are arranged in the reverse direction of the capacitor terminal arrangement direction, and the connection member has a positive-side conductive member connecting the positive terminals of the plurality of capacitors and a negative-side conductive member connecting the negative terminals of the plurality of capacitors. Therefore, each capacitor can be used without increasing the size of the capacitor unit and suppressing the increase in wiring inductance. Of the variation of the wiring inductance can be reduced.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a configuration of a capacitor unit according to an embodiment of the present invention.
FIG. 2 is a plan view of the capacitor unit of FIG.
FIG. 3 is an explanatory diagram showing a position when one capacitor is provided on a wiring board;
FIG. 4 is an explanatory diagram showing the relationship between the distance from the positive and negative external terminals in FIG. 3 to the connection position of the capacitor and the wiring inductance.
FIG. 5 is a plan view showing an arrangement in which all parallel capacitors are connected in the same polarity arrangement.
FIG. 6 shows a case in which all the capacitors connected in parallel are connected in the same polarity arrangement, a case in which the capacitors arranged closest to the positive and negative external terminals are connected in reverse polarity and the other capacitors are connected in the same polarity, It is explanatory drawing which shows the wiring inductance of the capacitor of each position.
FIG. 7 is a plan view showing a configuration of a capacitor unit according to another embodiment of the present invention.
FIG. 8 is a plan view showing a configuration of a capacitor unit according to another embodiment of the present invention.
FIG. 9 is an explanatory diagram for explaining the reason why the wiring inductance is reduced in the capacitor unit of FIG. 8;
FIG. 10 is a plan view showing a configuration of a capacitor unit according to another embodiment of the present invention.
FIG. 11 is a plan view showing a configuration of a capacitor unit according to another embodiment of the present invention.
FIG. 12 is a plan view showing a configuration of a semiconductor power conversion device according to another embodiment of the present invention.
FIG. 13 is a circuit diagram of the semiconductor power conversion device of FIG.
[Explanation of symbols]
11 to 14, 21 to 24 capacitor, 2 positive electrode side conductor,
2a positive external terminal, 3 negative conductor, 3a negative external terminal,
4 three-phase inverter, 6 wiring board, 10 capacitor unit,
46 Wiring board.

Claims (9)

It has a plurality of capacitors and connection members,
The capacitor has a positive terminal connected to the positive terminal of the DC circuit and a negative terminal connected to the negative terminal of the DC circuit,
The plurality of capacitors are arranged such that capacitor terminal arrangement directions from the positive terminal to the negative terminal of each capacitor are parallel to each other, and at least one of the plurality of capacitors has the capacitor terminal arrangement direction. It is arranged in the opposite direction to the capacitor terminal arrangement direction of the other capacitors,
The capacitor unit, wherein the connection member includes a positive conductive member connecting the positive terminals of the plurality of capacitors and a negative conductive member connecting the negative terminals of the plurality of capacitors. The positive and negative conductive members are plate-shaped positive and negative conductors facing each other at a predetermined interval in the z-axis direction of an xyz three-axis coordinate system,
2. The capacitor unit according to claim 1, wherein each of the capacitors is arranged such that each capacitor terminal arrangement direction is oriented in a direction intersecting with the z-axis. 3. The positive and negative conductive members are provided at one end of the positive and negative conductors in the y-axis direction at a predetermined distance from each other in the x-axis direction. Having a positive electrode side and a negative electrode side external terminal connected to
Each of the capacitors is disposed so as to face the positive-side conductor or the negative-side conductor so that the capacitor terminal arrangement direction intersects with the z-axis, and the positive terminal is connected to the positive-side conductor and A negative terminal is connected to the negative electrode conductor through the positive electrode conductor in the z-axis direction, or the positive electrode terminal is connected to the positive electrode conductor through the negative electrode conductor in the z-axis direction. The negative electrode terminal is connected to the negative electrode-side conductor, and the positive electrode terminal of at least one of the plurality of capacitors is greater than the positive electrode terminal of another capacitor when viewed from the z-axis direction. The negative electrode terminal of at least one of the plurality of capacitors is connected to the positive electrode conductor at a position close to the negative electrode external terminal. 3. The capacitor unit according to claim 2, wherein the capacitor unit is connected to the negative electrode-side conductor at a position closest to the positive electrode-side external terminal than the negative electrode terminal of another capacitor as viewed in the z-axis direction. 4. . The positive electrode side and the negative electrode side conductors are provided on both sides of an insulating substrate having a through hole forming portion that forms a through hole penetrating in the z-axis direction at a predetermined position, and the plurality of capacitors are provided. The capacitor according to claim 3, wherein the positive electrode terminal or the negative electrode terminal is connected to the positive electrode side conductor or the negative electrode side conductor through the through hole forming portion of the insulating substrate. unit. The capacitor unit according to claim 1, wherein the plurality of capacitors are arranged in the y-axis direction such that the capacitor terminal arrangement direction is parallel to the x-axis. 2. The capacitor unit according to claim 1, wherein the plurality of capacitors are arranged in the x-axis direction such that the capacitor terminal arrangement direction is parallel to the y-axis. 3. 7. The capacitor unit according to claim 5, wherein the plurality of capacitors are arranged in such a manner that the capacitor terminals of adjacent capacitors are arranged in the opposite direction. 8. The capacitor unit according to any one of claims 1 to 7, wherein the capacitor is a film capacitor. 9. The capacitor unit according to claim 1, further comprising: a semiconductor switching element connected to the positive and negative external terminals of the capacitor unit, wherein the positive and negative external terminals are provided. A semiconductor power converter, wherein a terminal is connected to a DC power supply, and the semiconductor switching element converts the DC to an AC.

Images