JPH10107571A - Noise filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a noise filter used in common to a plurality of devices energized by an AC power supply. SOLUTION: The noise filter 41 is manufactured as one electric component in which noise filter circuits 42, 43 are connected in cascade and new output terminals 57, 58 are provided to the cascade connection points. An AC power supply 10 is connected to input terminals 51, 52, a power input section of a control section 23 is connected to the output terminals 57, 58 and output terminals 53, 54 are connected to a power input section of an inverter 22. Thus, malfunction of the control section 23 caused by propagation nose Nc generated from the inverter 22 is prevented by the noise filter 41 being one electric component, which also attenuates both propagation noise Nc' caused by radiation noise Nr intruded from the inverter 22 to the control section 23 and a noise terminal voltage en resulting from the propagation noise Nc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to, for example, a device which is disposed and inserted between a device to which electricity is supplied from an AC power source and the AC power source, and which is inserted from the device to which the electricity is supplied.
While preventing noise from propagating to the power supply side,
The present invention relates to a noise filter device that blocks noise radiated from the C power cord to the outside.

[0002]

2. Description of the Related Art In recent years, attention has been paid to high use efficiency of a power supply, and a DC power generation circuit using a switching regulator and an inverter circuit for driving a motor and the like have been frequently used.

[0003] Since these circuits include a switching circuit, they can be a noise source that generates conduction noise and radiation noise. For example, when the noise source is directly connected to an AC power source via an AC cord, the noise generated at the noise source returns to the AC power source side via the AC cord as conduction noise. Noise also occurs. The conducted noise affects other electric devices connected to the AC power source, and the radiated noise affects AV (Audio Visual) devices including televisions, radios, CD players, telephones, and the like.

[0004] Therefore, the conduction noise and radiation noise generated from the noise source are, for example, VCCI standard, CI
It is subject to so-called EMI (Electro Magnetic Interference) regulations in various standards such as the SPR standard and the FCC standard, and it is necessary to suppress the level to a predetermined level or less.

[0005] In order to suppress noise, a noise filter device has conventionally been provided and inserted into a device between a power supply and the device for use. As is well known, the noise filter device is, for example, a terminal block (referred to as a terminal block metal case) attached to a metal case or a passive component L (coil, inductor) on a printed wiring board.
A C (capacitor) circuit is mounted, and if necessary, a metal case with a terminal block or a printed wiring board on which these LC circuits are mounted is shielded by a shield case such as a rectangular parallelepiped and provided to the market as one electric component. Have been.

FIG. 6 shows an example in which the rated voltage is 250 VA.
C shows a schematic configuration of the noise filter device 1 for a rated current of 10 A. The noise filter device 1 has a shield case 2. Input terminals 3 and 4 are provided at one end of the shield case 2, and output terminals 5 and 6 and a ground terminal 7 are provided at the other end. The size of the shield case 2 of the noise filter device 1 is approximately W
(Width) × L (length) × H (height) = 60 × 70 × 40
(Mm ³ ) = 168 (cc).

FIG. 7 shows the noise filter device 1 shown in FIG.
(Noise filter circuit) 8 is shown.

As can be understood from FIG. 7, a noise filter circuit 8 includes an inter-line capacitor C between input terminals 3 and 4.
1 is connected, and one end of the common mode choke coil L1 is connected. Grounding capacitors C2 and C3 are connected in series to the other end of the common mode choke coil L1, and output terminals 5 and 6 are connected. Further, a grounding terminal 7 is connected to a common connection point of the grounding capacitors C2 and C3.

[0009]

When there are a plurality of devices for supplying electricity from a single power supply (AC power supply or DC power supply), the devices to which the electricity is supplied are each generated by a noise source such as a switching regulator. In the case of a noise source, as shown in FIG. 8, noise filter devices 1a and 1b equivalent to the noise filter device 1 shown in FIG. Therefore, there is a problem that the cost, the mounting space, and the mounting cost of the noise filter device 1 are doubled.

[0010] For example, as shown in FIG. 9, when AC power is supplied to the inverter 22 and the control unit 23 via one noise filter device 1, noise Nc generated by the inverter 22 is indicated by a dotted arrow. As shown by, there is a possibility that the control unit 23 may erroneously operate as so-called conduction noise Nc via the AC power supply line. In FIG. 9, solid arrows indicate
The noise generated by the inverter 22 is radiated by the control unit 2
3 shows what is called radiation noise Nr.

In order to prevent the conduction noise Nc from flowing from the inverter 22 to the control unit 23, it is conceivable to connect the AC power supply 10 directly to the control unit 23 as shown in FIG. In the example, the control unit 23
Radiation noise Nr mixed from the inverter 22
Return to the AC power supply 10 as conduction noise Nc 'indicated by a dotted arrow, and the conduction noise Nc'
Noise voltage (voltage between noise terminals) generated in the power supply 10
May cause the aforementioned EMI disturbance.

SUMMARY OF THE INVENTION The present invention has been made in consideration of such problems, and has as its object to provide a small, lightweight, and low-cost noise filter device that can be commonly used for a plurality of devices to which electricity is supplied from a power supply. Aim.

[0013]

According to the present invention, for example, as shown in FIGS. 2 to 4, an input terminal is provided between an apparatus to which electricity is supplied from a power supply and the power supply, and an input terminal is connected to the power supply connection side. 51 and 52 are provided, and an output terminal 5 is provided on the device connection side.
In the noise filter device provided with 3, 54 and configured as one electric component, the noise filter device includes noise filter circuits 42 and 43 connected in cascade, and the noise filter circuit connected in cascade. Are provided with new output terminals 57 and 58 at the cascade connection point. In this case, at least two cascade-connected noise filter circuits, three, four,
, Etc., the number of stages can be increased as necessary.

According to the present invention, since a new output terminal is provided at a cascade connection point of a cascade-connected noise filter circuit, electricity is supplied to this new output terminal from a power supply (AC power supply or DC power supply). By connecting to another device, conduction noise does not flow from the other device to the power supply. In addition, as a result, a noise feedback circuit is inserted between another device connected to the new output terminal and a device connected to the original output terminal (referred to as an original device). Therefore, interference between the original device and other devices is reduced.

The cascade-connected noise filter circuit may be a circuit comprising a cascade-connected common mode choke coil.

By mounting the passive components constituting the noise filter circuit on a single printed circuit board, the size, weight and cost of the noise filter device can be reduced.

In each of the cascade-connected noise filter circuits, a capacitor is connected between input terminals, an input terminal of a common mode choke coil is connected, and an output terminal of the common mode choke coil is connected to each of the output terminals. If a capacitor is connected between the ground and the output terminal is connected, and these passive components are mounted on one printed wiring board, as a result, electricity is supplied from the power supply. A small, lightweight, low-cost noise filter device that can be used in common by a plurality of devices to be supplied is obtained.

[0018]

An embodiment of the present invention will be described below with reference to the drawings. In the drawings referred to below, those corresponding to those shown in FIGS. 6 to 11 are denoted by the same reference numerals, and detailed description thereof will be omitted. In addition, in order to avoid the trouble of repeatedly publishing the drawings, the drawings are referred to as necessary.

FIG. 1 shows a single-sided printed circuit board 3 on which a cascade-connected filter circuit of this embodiment is mounted.
1 shows a backside pattern diagram. This printed wiring board 31 is a single-sided glass epoxy board, and the size is
It is about 90 mm x 45 mm.

FIG. 2 shows a cascaded filter circuit mounted (mounted) on the printed wiring board 31 of FIG.
2 shows a front-side actual wiring diagram of the printed wiring board 31. FIG. By soldering the LC components and terminals based on the actual wiring diagram, the noise filter device excluding the shield case is completed. Therefore, FIG. 2 can be considered to show the configuration of the noise filter device 41 of this embodiment. In FIG. 2, the pattern is drawn as seen through the surface of the printed wiring board 31.

FIG. 3 shows an electric circuit diagram of the noise filter device 41 of this embodiment.

In FIG. 1, it can be seen that the pattern of the printed wiring board 31 is formed symmetrically with respect to the center line along the length direction. Ground pattern 32 on center line
Are formed, and in order from the left side in FIG.
a, 33b, intermediate lands 34a, 34b, and output lands 35a, 35b are formed symmetrically as patterns.

As can be seen from FIGS. 2 and 3, the noise filter device 41 of this embodiment has two stages of cascade-connected noise filter circuits 42 and 43.

The input-side noise filter circuit 42 includes input terminals 51 and 52, an inter-line capacitor C11, a common mode choke coil L11, a grounding capacitor C12,
C13, the output side noise filter circuit 43
Is composed of an inter-line capacitor C21, a common mode choke coil L21, grounding capacitors C22 and C23, and output terminals 53 and 54. New output terminals (also referred to as intermediate terminals) 57 and 58 are provided on the lands 34a and 34b corresponding to cascade connection points of the cascade-connected noise filter circuits 42 and 43.

In FIG. 2, an inter-line capacitor C11 is connected between input terminals 51 and 52. It should be noted that, for example, a connection terminal such as a Faston terminal is attached to the input terminals 51 and 52, or the terminals 3 and
4 and the like, a conductive wire portion of a wire material such as a heat resistant wire for soldering is soldered. In addition, the same processing is adopted as necessary for the terminals described below. Common mode choke coil L
Eleven input terminals 61, 62 are connected to the input terminals 51, 52, and output terminals 63, 64 of the common mode choke coil L11 are connected to the intermediate terminals 57, 58. The line-to-line capacitor C21 is connected between the intermediate terminals 57 and 58, and the input terminals 65 and 66 of the common mode choke coil L21 are connected. The output terminals 67 and 68 of the common mode choke coil L21 are output terminals 71 and 72.
And grounding capacitors C22 and C23 are connected between the output terminals 71 and 72 and the ground.

The noise filter device 41 composed of the printed wiring board 31 on which these passive components are mounted (mounted)
It is attached to the bottom side of a shield case (not shown) by attaching screws via the attaching holes 91 to 94, for example,
A device having the same shape as that shown in FIG. 6 (the reference numeral of this device is also denoted by 41) is completed. The noise filter device 41, which has been assembled in the shield case, has input terminals 51 and 52 and a ground terminal ｛ground terminal 5
5, 56, 71, 72 common terminal and ground terminal 102
(See FIG. 4).出力, output terminals 53 and 54 and new output terminals 57 and 58 are fixed.

FIG. 4 shows a motor control drive device 100 to which the noise filter device 41 configured as described above is applied.
Is shown.

In this case, the AC power supply 10 is connected between the input terminals 51 and 52 of the noise filter device 41. Output terminals 53 and 54 are connected to a power input terminal of the inverter 22. Electric power is supplied to the inverter 22 from the AC power supply 10 via the noise filter circuits 42 and 43. The power input terminals of the control unit 23 are connected to the new output terminals 57 and 58, and the control unit 23 is supplied with electricity from the AC power supply 10 via the noise filter circuit 42. The inverter 22 converts the rectified output obtained by rectifying the AC power into IGB
Switching is performed by the T and the MOSFET in accordance with the PWM signal, and the switching is supplied to the motor 21 via the drive circuit.

In this case, the conduction noise Nc generated by the inverter 22 is attenuated by the action of the rear (second stage) noise filter circuit 43 and almost leaks to the power input side of the control unit 23. Disappears. Further, even if the radiation noise Nr leaks from the inverter 22 into the control unit 23, the conduction noise Nc 'caused by this leak is attenuated by the front-side (first-stage) noise filter circuit 42,
The amount returned to the AC power supply 10 is attenuated. Further, the conducted noise Nc generated from the inverter 22 and going to the AC power supply 10 is naturally attenuated by the noise filter circuits 42 and 43 in both the first and second stages.

In this case, the capacitance values of the passive components constituting the noise filter circuit 42 and the noise filter circuit 43, respectively,
As the inductance value, a value (element value) can be selected according to the noise level of a device connected to the output side.
In the noise filter device 41 used in the device of FIG. 4, the values of the passive components of the noise filter circuit 43 on the output side close to the inverter 22 which is the noise source are replaced with the values of the passive components of the noise filter circuit 42 on the input side. , The amount of leakage of the conduction noise Nc from the inverter 22 to the control unit 23 can be reduced. The values of the passive components constituting the noise filter circuits 42 and 43 can be determined from the characteristics of the devices connected to the output side, their power supply capacities, the specified leakage current, and the like.

FIG. 5 shows measured data of the noise terminal voltage en of the AC power supply 10 in this embodiment (example of FIG. 4) and the noise terminal voltage en of the AC power supply 10 of the prior art (example of FIG. 10). 111 and 112 are shown. From FIG. 5, the measurement data (the data in the example of FIG. 4) 111 corresponds to the measurement data (FIG. 10).
Example) Compared to 112, the peak voltage of noise is about 40 d
It can be seen that the noise voltage is reduced by about 10 dBμV at BμV and average voltage.

As described above, by using the noise filter device 41 according to the above-described embodiment, the two noise filter devices 1a and 1b shown in FIG. A noise reduction effect equivalent to that used is achieved. That is, the noise filter device 41 according to this embodiment can be commonly used for the inverter 22 and the control unit 23, which are two devices to which electricity is supplied from the AC power supply 10.

The size of the noise filter device 41 including the shield case is approximately W (width) × L (length) × H (height).
= 60 × 100 × 40 (mm ³ ) = 240 (cc), and the noise filter device 1 according to the prior art (see FIG. 6)
Can be reduced by about 30% in volume, about 50% in weight, and about 30 to 40 in cost as compared to using two
% Can be reduced.

In the above-described embodiment, as the noise filter device 41, the capacitors C11 and C
21 and grounding capacitors C12, C13, C22, C2
However, when the noise generated in the device to which electricity is supplied is small, the capacitors C11 to C13 and C21 to C23 are removed to remove the common mode choke coil L11 and the common mode choke coil. It is also possible to provide a noise filter device as one electric component consisting of only the cascade connection of L12.

In the above-described embodiment, the noise filter device has a two-stage cascade connection circuit configuration of a noise filter circuit. However, a noise filter as one electric component having a cascade connection circuit configuration of three or more circuits is further provided. It can also be a device.

Further, the noise filter device can be manufactured integrally with the AC inlet of the device to which electricity is supplied from the power supply.

Further, in the above embodiment, AC
The noise filter device has a cascade circuit configuration of a noise filter circuit for a single-phase power supply.
A noise filter circuit for an AC three-phase power supply having an intermediate terminal provided by cascade-connecting noise filter circuits for line) can also be provided. Of course, it can also be used for a DC power supply.

Furthermore, in the above-described embodiment, the noise filter device is mounted on a single printed circuit board. Alternatively, the noise filter device may be mounted in a metal case with a terminal block. It goes without saying that a configuration in which the bolt terminal is fixed to the case and mounted in a metal case with a bolt terminal is also possible.

It should be noted that the present invention is not limited to the above-described embodiment, but can adopt various configurations without departing from the gist of the present invention.

[0040]

As described above, according to the present invention, a noise filter device is provided as a single electrical component having a new output terminal at a cascade connection point of a cascade-connected noise filter circuit. . By connecting this new output terminal to another device to which electricity is supplied from a power supply (AC power supply or DC power supply), the new output terminal can be used in common to a plurality of devices to which electricity is supplied from the power supply, and is small in size and light in weight. A low-cost noise filter device can be obtained.

[Brief description of the drawings]

FIG. 1 is a back surface pattern diagram of a printed wiring board on which a noise filter circuit component connected in cascade is mounted.

FIG. 2 is a substantial wiring diagram used for describing a configuration of an embodiment of the present invention.

FIG. 3 is a circuit diagram of one embodiment of the present invention.

FIG. 4 is a circuit diagram of a motor drive control circuit to which an embodiment of the present invention is applied;

FIG. 5 is a frequency characteristic diagram used for comparing a noise terminal voltage between an embodiment of the present invention and a conventional technique.

FIG. 6 is a perspective view generally showing an outer shape of a noise filter device.

FIG. 7 is a circuit diagram showing an electrical configuration of a general noise filter device.

FIG. 8 is a diagram provided for describing an example of use using two noise filter devices of the example in FIG. 8;

FIG. 9 is a diagram provided for describing a motor control drive device using one noise filter device of the example in FIG. 8;

FIG. 10 is a diagram provided for another description of a motor control drive device using one noise filter device of the example of FIG. 8;

11 is a diagram which is used for describing a motor control drive device using two noise filter devices of the example of FIG. 8;

[Explanation of symbols]

1, 1a, 1b, 41: noise filter device 2: shield case 3, 4, 51, 5
2 input terminal 5, 6, 71, 72 output terminal 10 AC power supply 11, 12 noise source 21 motor 22 inverter 23 control unit 31 printed circuit board 42, 43 noise filter circuit 57, 58 ... New output terminal (intermediate terminal) 100 ... Motor control drive device C1, C11, C21 ... Line capacitors C2, C3, C12, C13 ... Grounding capacitors L1, L11, L21 ... Common mode choke coil

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H05K 9/00 H05K 9/00 K // H01F 27/00 H01F 15/00 D

Claims (4)

[Claims] An electric terminal is provided between a device to which electricity is supplied from a power supply and the power supply, an input terminal is provided on the power supply connection side, and an output terminal is provided on the device connection side. In the noise filter device configured as a component, the noise filter device has a cascade-connected noise filter circuit, and a new output terminal is provided at a cascade connection point of the cascade-connected noise filter circuit. A noise filter device characterized by the above-mentioned. 2. The cascade-connected noise filter circuit according to claim 1, wherein said cascade-connected noise filter circuit comprises cascade-connected common mode choke coils, and a new output terminal is provided at a cascade connection point of said common mode choke coils. A noise filter device characterized in that: 3. The noise filter device according to claim 1, wherein the passive components forming the noise filter circuit are mounted on a single printed wiring board. 4. The apparatus according to claim 1, wherein each of the cascade-connected noise filter circuits includes a capacitor between input terminals, a common mode choke coil having an input terminal connected to the capacitor between input terminals, A noise filter device comprising a grounding capacitor to which one terminal is connected to an output terminal of a common mode choke coil, and these passive components are mounted on one printed wiring board.