JP2002252535A - Three-phase noise filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize a distance to ground by making impedances to across-the- line-capacitors from the AC power source line of each phase identical with each other. SOLUTION: The respective conducting patterns 21-23 are formed which are positioned at the respective vertexes of an equilateral triangle and correspond to the AC power source lines. A conducting pattern 24 is formed which is positioned at the center of the equilateral triangle and corresponds to ground. As a result, in each of the conducting patterns 21-23, distances from connection parts 31-33 of the AC power source lines to connection parts 41-43 of the across- the-line-capacitors CX1, CX2, CX3 are all equal. The wiring pattern from each of the AC power source lines to ground becomes the shortest.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a three-phase noise filter in which an across-the-line capacitor and a line bypass capacitor are mounted on a substrate on which a conductive pattern is formed.

[0002]

In general, this type of noise filter is characterized by either normal mode noise of a symmetric component transmitted between AC power lines or common mode noise of an asymmetric component transmitted between the AC power line and ground. It also has a built-in noise elimination circuit that effectively eliminates noise.

FIG. 3 is a circuit diagram of such a three-phase noise filter. In FIG.
Reference numerals 2 and 3 denote input terminals of a three-phase noise filter. As is well known, a three-phase AC power supply (not shown) for supplying AC voltages having u-phase, v-phase, and w-phase phases different by 120 °. Is connected. A common mode choke coil for removing low-frequency common mode noise is provided on each AC power supply line from each of the input terminals 1, 2, 3 to the output terminals 11, 12, 13 for connecting a load (not shown). L1, L2 and L3 are inserted and connected. These common mode choke coils L
1, L2 and L3, the u-phase and v-phase, the v-phase and w-phase,
Across the line capacitors CX1, CX2, CX3 for removing low-frequency normal mode noise connected between w-phase and u-phase AC power supply lines, and u-phase, v-phase, and w-phase AC power supplies Line bypass capacitors CY1, CY2, CY3 connected between line and ground for removing high-frequency common mode noise and normal mode noise
Are provided respectively.

Incidentally, in order to simplify the internal structure of the noise filter having the above circuit configuration, the cross filters CX1, CX2, CX3 which are lighter in weight than the common mode choke coils L1, L2, L3. In general, the line bypass capacitors CY1, CY2, and CY3 are mounted on a common board, that is, a printed board.

FIG. 4 shows an example of such a printed circuit board. Reference numeral 15 denotes a rectangular printed circuit board having a u-phase, v-phase, and w-phase AC power supply on its surface, that is, on the component mounting surface side. Conductive patterns 21, 22, and 23 corresponding to the lines are formed. 24 is a conductive pattern 24 corresponding to the ground.
Then, these conductive patterns 21 to 24 are formed on the printed circuit board 15 so as not to contact any of them. Each conductive pattern 21
24 to 24 are connection parts as plated through holes for making electrical connection to the outside with lead wires (not shown), for example.
31 to 34 are formed. Specifically, the connection portion 31 of the conductive pattern 21 is directly connected to the u-phase AC power supply line, the connection portion 32 of the conductive pattern 22 is directly connected to the v-phase AC power supply line, and the connection of the conductive pattern 23 The unit 33 is directly connected to a w-phase AC power supply line. Further, the connection portion 34 of the conductive pattern 24 is connected and fixed to a metal housing (not shown) of the noise filter by screwing or the like.

On the other hand, conductive patterns 21 and 22,
Conductive pattern 22, conductive pattern 23, and conductive pattern
Connecting portions 41, 42, and 43 for soldering and fixing cross-the-line capacitors CX1, CX2, and CX3, respectively, are formed as a pair of plated through holes between the conductive pattern 23 and the conductive pattern 21. Separately, the conductive pattern 21
And conductive pattern 24, conductive pattern 22 and conductive pattern 24,
Also, between the conductive patterns 23 and 24, connecting portions 51, 52, 53 for soldering and fixing the line bypass capacitors CY1, CY2, CY3 are formed as a pair of plated through holes. . Then, each lead wire of each of the across-the-line capacitors CX1, CX2, and CX3 is soldered and fixed to the corresponding connection portions 41, 42, and 43, and the line bypass capacitors CY1, CY2, and CY3 correspond to the corresponding ones. These components are electrically connected on the printed circuit board 15 by being soldered and fixed to the connection portions 51, 52, 53.

Incidentally, the printed circuit board 15 shown in FIG.
When the conductive patterns 21 to 24 are formed in accordance with the outer shape of the printed circuit board 15, for example, when attention is paid to the conductive pattern 21 corresponding to the u-phase AC power supply line, the connection portion 31 directly connected to the AC power supply line The length from the connection 31 to the connection 41 of the across-line capacitor CX1 is different from the length from the connection 31 to the connection 41 of the across-the-line capacitor CX1. Across the line capacitors CX1,
The impedances to CX2 and CX3 cannot be equalized. In addition, while the connection parts 31, 32, and 33 of the AC power supply lines are provided on one side of the printed circuit board 15, the ground connection parts 34 are provided on the other side of the printed circuit board 15. The distance from the AC power supply line to the ground is long, and in the arrangement of the conductive patterns 21 to 24 shown in FIG.
Ideal characteristics cannot be realized as a noise filter.

Therefore, the present invention solves the above problems,
The aim is to provide a three-phase noise filter that has the same impedance between the AC power supply line of each phase and the cross-the-line capacitor, and that has the ideal characteristic of minimizing the distance to the ground. Aim.

[0009]

In order to achieve the above object, a three-phase noise filter according to the present invention comprises: an across-the-line capacitor connected between AC power supply lines; In a three-phase noise filter in which line bypass capacitors connected to grounds are mounted on a substrate on which a conductive pattern is formed, each of the conductive patterns corresponding to the AC power supply line of each phase is replaced by a regular triangle. The same shape is formed on the substrate at each vertex, and a conductive pattern corresponding to the ground is formed on the substrate at the center of the equilateral triangle.

In this case, at each vertex of the equilateral triangle,
Since the respective conductive patterns corresponding to the AC power supply lines are formed, the across-the-line capacitors connected between the AC power supply lines are necessarily arranged in a Δ shape. Since a conductive pattern corresponding to the ground is formed at the center of the equilateral triangle, the line bypass capacitors connected between each AC power supply line and the ground are necessarily arranged in a Y-shape. Is done. For this reason, in each conductive pattern corresponding to the AC power supply line, the distance from the connection part of the AC power supply line to the connection part of the ACROSS-the-line capacitor is all equal, and the AC power supply line of each phase has the same distance. The impedance to the line capacitor can be the same. In addition, the wiring pattern from each AC power supply line to the ground via the line bypass capacitor is also minimized,
Ideal characteristics can be realized as a noise filter.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a three-phase noise filter according to the present invention will be described below with reference to the accompanying drawings. The same parts as those in the conventional example are denoted by the same reference numerals, and the description of the common parts will be omitted because they are redundant.

FIG. 1 shows an improved printed circuit board 15 according to the present embodiment, and the surface of the printed circuit board 15 is provided with an across-the-line capacitor C as is well known.
X1, CX2, CX3 and line bypass capacitor CY
1, CY2 and CY3 are implemented. The electrical configuration of the noise filter including these components is exactly the same as that shown in FIG.

The printed circuit board 15 according to the present embodiment has a circular outer contour, and its surface, that is, the component mounting surface, is located at each vertex of an equilateral triangle T, and has u-phase, v-phase, and w-phase AC power supply lines. Are formed corresponding to the conductive patterns 21, 22, and 23. These conductive patterns 21, 22, and 23 are preferably formed in the same shape and the same thickness in order to make the electrical characteristics of the AC power supply lines as uniform as possible. In this embodiment, each of the conductive patterns 21, 22, and 23 is formed in a circular shape with the vertex of the equilateral triangle T as a center. At the center of the equilateral triangle T, a conductive pattern 24 corresponding to the ground is formed in a circular shape like the conductive patterns 21, 22, and 23.

The printed circuit board 15 is made of cross-the-line capacitors CX1, CX2, CX
The connection portions 41, 42, 43 of X3 and the connection portions 51, 52, 53 of the line bypass capacitors CY1, CY2, CY3 are formed as plated through holes, respectively. Then, in order to arrange these components on the component mounting surface of the printed circuit board 15 without crossing each other, the cross-over-the-line capacitors CX1,
At the positions where CX2 and CX3 are arranged, connecting portions 41, 42 and 43 are respectively formed, and from each vertex of the equilateral triangle T toward the center, that is, in a Y shape, the line bypass capacitors CY1 and CY are formed.
Connection portions 51, 52 and 53 are formed at positions where 2, CY3 are arranged.

A distance D1 from a connection point 31 of the conductive pattern 21 directly connected to the u-phase AC power supply line to a connection point 41 at which one end of the across-the-line capacitor CX1 is fixed by soldering; A distance D2 from the connection point 31 to the other end of the cross-over-the-line capacitor CX3 to be soldered and fixed, and a distance D3 from the connection point 31 to a connection point 51 to be soldered and fixed to one end of the line bypass capacitor CY1.
Are all equal (D1 = D2 = D3). Further, the other conductive patterns 22 are also connected to the crossing point 32 which is directly connected to the v-phase AC power supply line.
The distance from the connection point 41 for soldering and fixing the other end of X1, the distance from the connection point 32 to the connection point 42 for soldering and fixing one end of the cross-the-line capacitor CX2, and the connection point 31
And the connection point 52 to which one end of the line bypass capacitor CY2 is fixed by soldering is all equal, and the conductive pattern 23 is also connected across the connection point 33 directly connected to the w-phase AC power supply line.・ The distance from the connection point to the connection point at which the other end of the capacitor CX2 is fixed by soldering, and the Across the Line capacitor C from the connection point 33
The distance from the connection point 33 where one end of X3 is fixed by soldering is equal to the distance from the connection point 33 to the connection point 53 where one end of the line bypass capacitor CY3 is fixed by soldering. Thus, each connection point 31, 32, 33 directly to the AC power line
Can be made equal to the distances from the capacitors CX1 to CX3 and CY1 to CY3 because the conductive patterns 21 to 23 of the same shape corresponding to the respective AC power supply lines are geometrically connected to each vertex of the equilateral triangle T as described above. This is because the conductive pattern 24 corresponding to the ground is disposed at the center of the equilateral triangle T. And the equilateral triangle T and thus the printed circuit board
At the center point of 15, a ground connection portion 54 is formed as a plated through hole.

In order to mount the printed circuit board 15 shown in FIG. 1 on the main body of the noise filter, first, the respective lead wires of the cross-over-the-line capacitors CX1, CX2, CX3 are inserted into the connection portions 41 to 43, The respective lead wires of the line bypass capacitors CY1, CY2, CY3 are inserted into the connection parts 51 to 53, and these lead wires are connected by soldering at the connection parts 41 to 43, 51 to 53. Then, a u-phase AC power supply line from the other end of the common mode choke coil L1 to the output terminal 11 is connected to the connection portion 31 of the conductive pattern 21, and v is connected to the output terminal 12 from the other end of the common mode choke coil L2. A phase AC power supply line is connected to the connection part 32 of the conductive pattern 22, and a w-phase AC power supply line from the other end of the common mode choke coil L 3 to the output terminal 13 is connected to the connection part 33 of the conductive pattern 23. . Further, one ends of the common mode choke coils L1 to L3 are connected to the input terminals 1 to 3, respectively, and the ground connection portion 54 is connected to a metal housing of the noise filter.
(Not shown). At this time, since the connection portion 54 is located at the center of the printed board 15, the printed board 15 can be stably mounted at one point.

Across the line
When the capacitors CX1 to CX3 and the line bypass capacitors CY1 to CY3 are mounted, the distances from the connection parts 31 to 33 to the connection parts 41 to 43 in the same conductive pattern 21 to 23 are all equal, and AC power line from
The impedance reaching the line capacitors CX1 to CX3 is the same. In addition, since the conductive pattern 24 corresponding to the ground is formed at the center of the conductive patterns 21 to 23 corresponding to the respective AC power supply lines, each AC power supply line is connected to the ground via the line bypass capacitors CY1 to CY3. , The shortest wiring pattern is obtained, and ideal characteristics as a noise filter can be realized.

FIG. 2 is an exploded perspective view showing an example of a three-phase noise filter using the printed circuit board 15. In the figure, 61 is a base provided with input terminals 1 to 3 protruding outward, 62 is a cap provided with output terminals 11 to 13 and ground terminal 55 protruding outward. By covering with the base 61, the common mode choke coils L1 to L
3 and a printed circuit board 15 with a capacitor are enclosed in a cylindrical main body 63. The ground terminal 55 is electrically connected to the connection part 54. The printed circuit board 15 is circular as described above, and the common mode choke coils L1 to L3 also have a toroidal shape in which windings are wound around a ring-shaped magnetic core. Choke coil L
By arranging 1 to L3 in a line, a three-phase noise filter having a cylindrical outer shape can be easily obtained.

As described above, according to the above-described embodiment, the cross-over power supply connected between the three-phase AC power supply lines is provided.
The line capacitors CX1, CX2, CX3 and the line bypass capacitors CY1, CY2, CY3 connected between the respective AC power supply lines and the ground are connected to conductive patterns.
In a three-phase noise filter mounted on a printed circuit board 15 which is a substrate on which 21 to 24 are formed, each conductive pattern 21 to 23 corresponding to an AC power supply line of each phase is formed by an equilateral triangle T.
Are formed on the printed circuit board 15 in the same shape at the vertices of the
Are formed on the printed circuit board 15 at the center of the printed circuit board.

In this case, each conductive pattern corresponding to the AC power supply line is located at each vertex of the equilateral triangle T.
Since 21 to 23 are formed, the across-the-line capacitors CX1, CX2, CX3 connected between the AC power supply lines
Are necessarily arranged in a Δ-shape. Further, since the conductive pattern 24 corresponding to the ground is formed at the center of the equilateral triangle T, the line bypass capacitors CY1, CY2, C2 connected between each AC power supply line and the ground are formed.
Y3 is necessarily arranged in a Y-shape. For this reason, in each of the conductive patterns 21 to 23, the connection portions 31 to 33 of the AC power supply line are provided.
Across the line capacitors CX1, CX2, C
The distances to the connection portions 41 to 43 of X3 are all equal, and the impedance from the AC power supply line of each phase to the across-the-line capacitors CX1, CX2, CX3 can be made equal. Also, the line bypass capacitor CY
The wiring pattern from each AC power supply line via 1, CY2 and CY3 to the ground is also minimized, and ideal characteristics as a noise filter can be realized.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention. For example, the printed circuit board 15 may not be circular as in the present embodiment, but may be an equilateral triangle or a rectangle.

[0022]

According to the three-phase noise filter of the present invention,
The impedance from the AC power supply line of each phase to the across-the-line capacitor can be made the same, and ideal characteristics that can minimize the distance to the ground can be realized.

[Brief description of the drawings]

FIG. 1 is a front view of a printed circuit board for a three-phase noise filter according to an embodiment of the present invention. It is a circuit diagram.

FIG. 2 is an exploded perspective view of a three-phase noise filter showing one embodiment of the present invention.

FIG. 3 is a circuit diagram of a three-phase noise filter showing a conventional example.

FIG. 4 is a front view of a printed circuit board for a three-phase noise filter showing a conventional example.

[Explanation of symbols]

 15 Printed circuit board (board) 21 to 24 Conductive pattern CX1, CX2, CX3 Across the line capacitors CY1, CY2, CY3 Line bypass capacitors

Claims (1)

[Claims] 1. An ACROSS-the-line capacitor connected between AC power supply lines, and a line connected between each AC power supply line and ground.
In a three-phase noise filter in which a bypass capacitor is mounted on a substrate on which a conductive pattern is formed, each of the conductive patterns corresponding to the AC power supply line of each phase is located at each vertex of an equilateral triangle and has the same shape. And a conductive pattern corresponding to the ground is formed at the center of the equilateral triangle on the substrate.