TWI542145B - Line noise attenuator - Google Patents

Description

Line noise attenuator

The invention relates to a line noise attenuator for attenuating noise currents superimposed on a power signal line to purify an electromagnetic environment.

The noise current superimposed on the conductor line connected to the ground line or the power supply line of the electronic device causes the common mode current to become the main body as a result of the operation of the conductor line as the antenna. Further, in a conductor line such as a power supply line formed by such a conductor line, the wiring pattern is different, and the conductor line is changed in the direction in which the conductor line is changed, and a part of the common mode current in which the conductor line generates a discontinuous point is converted into a normal one. Mode current.

The noise attenuator is for removing and mitigating obstacles caused by two noise currents of a common mode and a normal mode which are superimposed on various conductor lines, and such a noise attenuator is disclosed in Patent Document 1.

The noise filter disclosed in Patent Document 1 is a structure for preventing a resonance phenomenon between a capacitor for removing normal mode noise and a choke coil for suppressing high harmonic current. The noise attenuator reduces the peak of the input current by increasing the passage time of the input current in the low frequency region in the choke to suppress the high harmonic component. Moreover, the capacitor in the power supply device absorbs normal noise, and even the noise in the normal mode passes through the capacitor and the feedback line and is reflected toward the AC power supply side. Further, by connecting the resistors in parallel with the choke coil, the series resonance phenomenon caused by the choke coil and the capacitor is suppressed.

Further, Patent Document 2 discloses a two-terminal safety ground line noise filter that is mounted on a ground line of an electronic device having a different capacitance to ground.

[Patent Document 1] Japanese Laid-Open Patent Publication No. Hei 8-265085.

[Patent Document 2] Japanese Patent No. 3957206.

The noise filter disclosed in Patent Document 1 is for solving the problem that the 17th to 23rd harmonic currents caused by the series resonance phenomenon of the capacitor and the choke coil exceed the limit value of the specification. By adding a resistor to the combination of the capacitor for normal mode noise removal and the choke coil for suppressing high harmonic current, the 17th to 23rd harmonic currents are also improved to become limit values. the following.

However, in Patent Document 1, in the case of suppressing the normal mode noise by the capacitor, in the case of the common mode, since the voltage across the capacitor becomes the same voltage, it is impossible to make a short circuit by the capacitor so that the high frequency noise current is directed to the AC power source side. reflection.

Further, although the resistor is connected in parallel to the choke coil, since the resistor is used to suppress the series resonance phenomenon with the capacitor, the resistance value is limited to a value for suppressing the series resonance phenomenon. Although there is a current flow in the resistor, power consumption is caused by the resistor. However, the power consumption is set to suppress the series resonance phenomenon. Even if the normal mode noise flows through the resistor, the resistance value is obtained. It is suppressed to a low level, and the degree of suppression of noise noise is not yet required to suppress the noise current.

Further, in Patent Document 1, the inductance of the choke coil and the resistance value of the resistor are obtained based on the measured data. As described above, the power supply line is assumed to have a different wiring pattern, and a discontinuous point is generated due to the arrangement of the changed direction, and a part of the common mode noise current is converted into a normal mode noise current. In the case where the current is almost in the common mode, as described above, since the voltage across the capacitor is the same voltage as described above, the noise caused by the capacitor cannot be reflected toward the AC power source side, and it is difficult to cope with it. Noise barriers in a common mode.

Further, Patent Document 2 utilizes a magnetic saturator of an inductor, and magnetically saturates the inductor by a low-current current of a large current value which flows through the machine and causes an obstacle on the machine, and discharges the low-frequency current to the ground to protect the machine. A high-frequency noise small current that overlaps the ground line is thermally consumed by a resistor in parallel with the inductor. When the technique of Patent Document 2 is used as it is in the power system, since the current value of the low-frequency power source current flowing through the conductor of the power system is large, the inductor is magnetically saturated, and the high-frequency noise current system superimposed on the conductor Flowing into the machine without being blocked by the inductor causes the machine to encounter obstacles caused by high frequency noise currents.

Therefore, when the technique of Patent Document 2 is constructed as a noise filter of a power system, it is necessary to change viewpoints to establish a design theory of a noise filter suitable for a power system. Moreover, after examining the actual molded inductor, it was found that an inductor having an inductance value for preventing high-frequency noise current without causing magnetic saturation was developed, and it is necessary to develop to overcome the problem. Inductor.

SUMMARY OF THE INVENTION An object of the present invention is to provide a line noise attenuator which does not use a capacitor which causes a series resonance phenomenon, and which is not magnetically saturated due to a low-frequency signal current flowing through a conductor, and is used to suppress a power supply of the same wiring form by using a resistor. A common mode of noise current, such as a line, is used to power consumption until the obstacle is removed.

To achieve the object, a line noise attenuator according to the present invention is a line noise attenuator that attenuates a noise current superimposed on a conductor line for supplying signal power from a low frequency signal power source to a load to purify an electromagnetic environment. The line is actuated as an antenna for transmitting and receiving high-frequency noise current, and includes: an inductor that allows low-frequency signal power to flow; and a resistor that is set to be a reactance value of the inductor in an angular frequency of the noise current. The resistance value of the high-frequency noise current flowing into the inductor is interrupted, and the high-frequency noise current is replaced by heat by the resistance value, and the ratio of the inductance of the inductor to the resistance value of the resistor is fixed. In a certain amount, the inductor has the inductor and the resistor.

According to the present invention, the noise current flowing through a conductor line such as a power supply line that supplies signal power from a signal power source to a load is a capacitor that does not cause a series resonance phenomenon, and is not magnetically saturated due to a low-frequency signal current. Regardless of the wiring pattern, the power consumption of the common mode noise current flowing through the power line or the signal line can be removed to remove the obstacle.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

The basic principle of the embodiment of the present invention is based on the fact that focusing on the operation of the conductor line connected to the electronic device as an antenna is a major factor in the noise current. The present inventors first adopted this antenna theory, and there is no precedent for developing this theory. In the following, refer to the document J, D, Kraus "Antennas" Translator: Tanimura, Modern Science Society "Antenna" Showa 47th Edition (Document 1), Vol. 49, and Kurokawa, "Introduction to Microwave Circuits", Maruzen ( Co., Ltd., Showa 38, page 34 (Document 2).

The noise current superimposed on the conductor line connected to the ground line or the power supply line of the electronic device is such that the common mode current becomes the main body as a result of the operation of the conductor line as the antenna. Further, in the conductor lines such as the power supply lines among the conductor lines, the wiring patterns are different, and the conductor lines are redirected to cause discontinuities in the transmission path of the conductor lines, and a part of the common mode current is Transform into normal mode current.

Accordingly, a noise attenuator is proposed which can effectively remove and alleviate the obstacle caused by the noise of the dual mode superimposed on various conductor lines.

As a result of the operation of the antenna line connected to the electronic device as an antenna, the equivalent circuit is as shown in Fig. 7 (Document 1). In this case, an example in which a ground line is used as a conductor line is taken, and a part of the conductor line forming the circuit is not a wire but is grounded.

In Fig. 7, the internal impedance of the conductor wire 4 that operates as an antenna is Z _a = R _r + jX _a , and the noise disturbance load impedance of the electronic device connected to the conductor wire 4 is set to Z. _L = R _L + jX _L . The noise disturbance load referred to herein refers to a virtual load in which an electronic device causes an obstacle due to a noise current, and cannot be clearly visually observed or measured, and is generally regarded as a parasitic capacitance between an electronic circuit and a power line in a machine frame. And resistance. In this case, the energy consumed by the noise disturbance is replaced by one resistance. Therefore, hereinafter, it is simply referred to as an obstacle load, and R _{L is} set as the resistance component for generating power consumption of the noise disturbance.

Now, in the equivalent circuit shown in FIG. 7, the conductor lines of the electronic device before the load input terminal 4 disorder Tl, T2 noise voltage is set to V _n, the noise current is set to I _n, becomes in imparting When the amount of the sub-transformation is below the amount of the equation (Document 2), if the input voltage to the conductor line 4 acting as the antenna is set to E _n ,

From the 7th figure

V _n = E _n - Z _a I _n (3)

The value represented by the equation (4) is the maximum noise power value that causes the noise problem.

The value shown in the formula (4) is the maximum noise power value (replaceable power value) that can be supplied to the obstacle load when the conductor line connected to the power supply line or the ground line of the electronic device functions as an antenna. . In other words, the value shown in (4) is the maximum noise power that the conductor wire can receive from the electromagnetic environment as the antenna, and the maximum value of the noise power that can be assigned to the electronic device noise disturbance, R _r =R _L , And in the case where X _a = -X _{L is} established, the noise power for the obstruction resistance R _L is given.

Moreover, under the matching condition of R _r = R _L , X _a = -X _L , since E _{n -} Z _a I _n = Z _L I _n , E _n = (Z _a + Z _L ) I _n , due to Z _L = Z _a *, so (2) becomes,

∣b _n ∣ ² is interpreted as the noise power received by the conductor line 4 as the antenna because the conductor line 4 acting as the antenna does not satisfy the matching condition, and the display is performed under the matching condition. Its power is zero. That is, the received noise power is all consumed by the power on the barrier resistance R _L of the electronic device.

Now, use (1) and (2) and try to find (∣a _n ∣ ² -∣b _n ∣ ² )

, W _nL represents the power consumption that the barrier load resistance consumes in the normal state (unmatched state).

The reduction of the obstacle caused by the noise power means that the right side W _{nL of the} equation (6) is reduced, and the inductor _WrL is reduced by inserting an inductor into the circuit.

Conventionally, in the four-terminal type filter used as the noise filter of the power supply line, the inductor is constructed to be effective only for the common mode noise current (see Patent Document 1). This is related to the denominator of (6) ) plus has become The angular frequency increase characteristic of the reactance component (inductor) is the same function. Here, ω _n is the angular frequency of the noise current, and L is the inductance of the inductor.

That is, (X _a + X _L ) ² in the formula (6) becomes (X _a + X _L + X _f ) ² and is formed

In order to become W' _nL < W _nL , it is necessary to be (X _a + X _L + X _f ) ² > (X _a + X _L ) ² . Therefore, when (X _a + X _L ) is capacitive, there is a case where will be necessary to use _{X f> -2 (X a +} X L) as X _f is an inductor.

When the inductor inserted into the conductor line is an inductor such as X _f <-2(X _a +X _L ), since W′ _nL >W _nL is caused, the countermeasure becomes a so-called obstacle load. The problem of the reverse effect of increasing the power consumption by the resistor.

On the other hand, ∣b _n ∣ ² and ∣b' _n ∣ ² in the equations (6) and (7) become

, relative to X _f →∞, become

The ∣b' _n ∣ ² system receives almost the reversed power that is fed back to the power supply side via the conductor line (feedback line).

Also, after trying to find (∣b' _n ∣ ² -∣b _n ∣ ² ),

When (X _a +X _L ) is capacitive, since it is ∣b′ _n ∣ ² >∣b _n ∣ ² under the condition of X _f &gt; -2(X _a +X _L ), it is indicated by As the inverse power increases, the barrier power will decrease.

Further, in the equation (8), if R _r = R _L and X _a = -X _L in the antenna matching condition, ∣b _n ∣ ² becomes 0, and the maximum reception in the case where the conductor line 4 functions as an antenna The noise power is not retrograde or re-radiative, which is consistent with the result of equation (5).

According to the countermeasure against the noise reduction of inserting the inductor into the various conductor wires 4, it also has the opposite effect, and only causes an increase in retrograde power, and also does not contribute to the purification of the electromagnetic environment.

Therefore, the effect of the case where the inductor is replaced with a pure resistor is reviewed here. That is, if ω _n L R, the case where the inductor is replaced by a pure resistor is equivalent.

When compared with the formula (7), depending on the presence of the resistance R, W〞 _nL <W _{nL is} apparent, and the power consumption of the barrier load resistor R _L is reduced. In this case, the retrograde power becomes,

If you can become R When (X _a +X _L ) and (R _r -R _L )≒R are used to select the value of the parallel resistance R, ∣b′ _n ∣ ² becomes infinitely small, and the retrograde power system approaches zero.

Further, the inductor X _f is replaced with a resistor R, to find X _f = R ^{_{(|b 'n | 2 -|b "}} n | 2) , the became

If R R _L , R _r and R ∣X _a +X _L ∣, it becomes

, It represents a part of the noise power is consumed by the resistor R, an inductor than X _f, i.e., reverse power re-radiate more power is reduced. This reduction is dependent on equation (12).

In the embodiment of the present invention, it has been verified that the noise disorder power and the retrograde power in the electronic device can be reduced by replacing the inductor with a pure resistor. However, the power supply line is required to easily circulate a signal current of a predetermined power supply frequency or the like. In particular, since the signal line needs to flow a signal current of a predetermined frequency, it is not possible to insert only the resistor into the conductor line.

Therefore, in the embodiment of the present invention, in the power supply line of the conductor line 4 which is an antenna operation shown in Fig. 1(a), the fundamental frequency current (low-frequency signal current) is easily circulated and is high-frequency mixed. The current is supplied to the power consumption, and the configuration of the simplest circuit element that is difficult to circulate is used as a basic configuration. That is, in the embodiment of the present invention, as shown in the first diagram (a) of Fig. 1, the inductor 1 and the resistor 2 are connected in parallel, and the simplest circuit element is constructed.

When the configuration shown in the first diagram (a) is made, the inductance L of the inductor 1 and the resistance value R of the resistor 2 can be determined, so that the power frequency current (low frequency signal current) in the low frequency domain is in the inductor 1 The side is circulated, and the noise current (high-frequency noise current) in the high-frequency range flows on the side of the resistor 2. For example, when the inductance L of the inductor 1 is set to 10 mH and the resistance value R of the resistor 2 is set to 50 Ω, the current of the power supply frequency of 50 Hz (low-frequency signal current) is 50 Ω because the reactance of the inductor 1 is 3 Ω. 3Ω, the power supply frequency current is almost circulated on the inductor 1 side. On the other hand, with a high-frequency noise current of 10 kHz, the reactance of the inductor 1 is approximately 630 Ω, and this high-frequency noise current circulates almost on the side of the resistor 2 and is consumed by the power. Therefore, it can be considered as equivalent to replacing the inductor 1 with a pure resistor for a high-frequency noise current of 10 kHz or more.

In the embodiment of the present invention, the basic circuit configuration shown in the first diagram (a) of FIG. 1 is inserted into two power supply lines to put the noise attenuator into practical use.

The signal transmission in the conductor line 4 like a signal line such as a power line is performed in a so-called normal mode. Conventionally, it has been necessary to use a core material having a high frequency response property in the inductor of the noise filter used for the power supply line. However, the core material has a drawback that magnetic saturation is likely to occur due to a low current value. Therefore, in the conventional noise filter, a structure is constructed in which two windings of the same number of turns are applied to one core material in order to avoid magnetic saturation, and the magnetic fluxes cancel each other by the reciprocating current. Therefore, the inductor in this case becomes effective only for the common mode noise current.

Although it is described in the balun circuit of antenna engineering, even if it is intended to supply power to the linear antenna in the normal mode, the discontinuity of the transmission line generated at the connection portion with the antenna will cause the normal mode. It is understandable that the portion of the current is transformed into a common mode. Therefore, in the case where the power supply line (the conductor line 4) is connected, a part of the common mode noise current is converted into the normal mode due to a discontinuous point such as a direction change at a right angle, and Patent Document 1 also Not without utility.

The line noise attenuator according to the embodiment of the present invention can effectively suppress the noise current and the noise power consumption of the common mode and the normal mode dual mode, but is inserted into the signal line, particularly when inserted into the power line. What will become the problem is that the magnetic saturation of the iron core material gives the limit of the effective current value.

Therefore, in the line noise attenuator according to the embodiment of the present invention, the number of windings in one core material is limited to a limit number which is magnetically saturated at a desired signal current value, and the resistor is connected in parallel on the inductor 1. The component of 2 is a unit component, and the noise attenuator which is resistant to a desired current such as a power supply line is put into practical use. In addition, the limit number of magnetic saturation is determined by the current value flowing through the conductor line, and is not the only one that determines the current value.

The line noise attenuator according to the embodiment of the present invention is connected in parallel to the inductor 1 and the resistor 2 shown in Fig. 1(a) to form a unit element, and the unit elements are made as shown in Fig. 1. (b) Inline (series) connections as shown. Furthermore, the inductance L _i (L ₁ , L ₂ , L ₃ , ‧‧‧L _n ) of the inductor 1 and the resistance value R _i (R ₁ , R ₂ ‧‧‧R _n ) of the resistor 2 are It is fixed to a certain amount.

If the impedance of the i-th unit element in the figure (b) of Fig. 1 is set to Z _i , the display is

here,

Therefore, the composite impedance Z of two or more unit elements connected in series to the power supply line (conductor line 4) is

Here, if set

= =‧‧‧= =‧‧‧= =θ (18)

Become

For the angular frequency ω of any noise current, if R _i /ωL _i =x, the equation (19) becomes

In this case, [omega] as the noise attenuator the desired noise limit angular frequency ω _n, In terms can be _{R i / ω n L i =} x = 1 i.e. R _i = ω _n L _i is set to R The value of _i and L _i , (20)

Therefore, at a noise angle frequency higher than the set lower limit noise angle frequency , when x→0, then z → .

Here, the ratio of the inductance L _i (L ₁ , L ₂ ‧‧‧L _n ) of the inductor 1 to the resistance value Ri (R1, R2‧‧‧Rn) of the resistor 2 is fixed to a certain amount, which means ω Set the desired noise lower limit angular frequency ω _n in the noise attenuator to set R _i and L _i in such a manner that R _i /ω _n L _i =x=1, that is, R _i =ω _n L _i value. Further, R _i means the resistance value of the resistor 2 _i in the i-th unit element connected in series as shown in the figure (b) of Fig. 1, and L _i means that it is as shown in Fig. 1 ( b) The inductance of the inductor 1 _i in the i-th unit element connected in series as shown.

Here, an example in which the power line is used with a noise attenuator is given. The inductor 1 is used until the maximum current is 10 A or is not saturated, and a ferrite toroid coil having an inductance of 0.4 mH is used as the inductor 1. When the effective lower limit noise frequency is set to 10 kHz, R _i = 25 Ω. If this unit element is used with three inductors 1 on each of two power lines, ΣR _i =150 Ω. Further, when the effective lower limit noise frequency is 50 kHz, R _i = 125 Ω is set, and the total resistance value is 750 Ω.

Further, in the embodiment of the present invention, as shown in Fig. 2, since the retrograde electric power is also consumed, the circuit elements shown in Fig. 1(b) are balanced on the two conductor wires 4 and the conductor wires 4. Ground connection. Figure 2 also contains signal power supply 3 and load 5. Further, in Fig. 2, the conductor wire is formed in a two-wire type, but it is not limited thereto, and may be a three-wire type.

According to the line noise attenuator of the embodiment of the present invention, the noise current superimposed on the conductor line such as the power supply line or the like which is actuated as the linear antenna is guided by the pure resistor to consume power, and the electronic device connected to the conductor line is removed. The noise impaired. In this case, the noise disturbance in the electronic device can be removed, and the resistance value of the resistor 2 connected in parallel with the inductor 1 must be increased to a necessary value or more. Another purpose of the line noise attenuator according to the embodiment of the present invention is to purify the noise electromagnetic environment by consuming the noise current by the resistor and minimizing the re-radiation power from the conductor line acting as the wire antenna.

For this reason, it is necessary to know the value of the impedance Z _a of the conductor wire 4 actuated as the linear antenna shown in FIG. 6 and the impedance Z _L of the load as the noise current load. Although it is not necessary to know the values correctly, the constant of the line noise attenuator can be determined by knowing the approximate value. Accordingly, the following is a review of the means for knowing the values of X _a and Z _L in an electronic device that is subject to noise disturbance.

Fig. 3 and Fig. 4 show an example of measuring the spectrum of the noise current by a clamp type ammeter connected to a ground line of a large electronic device for determining the constant of the noise attenuator. Figures 3 and 4 show the spectrum of the sampled data A, B, C, D, E, F after actual measurement of the noise current superimposed on the various ground lines provided in the electromagnetic environment. In Figs. 3 and 4, the horizontal axis takes the frequency (kHz), and the vertical axis takes the current value (dBμA) to display the spectrum. In Fig. 3, the spectrum of the sampled data A, B, and C at a frequency of 10 kHz to 100 kHz is shown, and in Fig. 4, the spectrum of the sampled data D, E, and F at a frequency of 0.1 MHz to 1 MHz is shown. It can be clearly seen from Fig. 3 that the spectrum of the noise current below 100 kHz is various in size, and the frequency of the noise current which is mainly a noise disturbance factor is unknown. However, it is reasonable to assume that the maximum current amplitude of the noise current is reasonable. Note the noise current of 30 kHz in Figure 3. When the 30 kHz noise current is consumed by the line noise attenuator according to the embodiment of the present invention and the noise of the target electronic device is removed, it is necessary to know the impedance of the conductor line 4 which is actuated as the linear antenna. Z _a and the magnitude of the impedance Z _L of the noise barrier load.

When the magnitude of the impedance Z _{a of the} conductor wire 4 and the impedance Z _L of the noise disturbance load are to be known, measurement using two inductors is performed. Now, if the inductances of the two inductors are L ₁ and L ₂ and the inductance value is known, the reactance values X ₁ and X _{2 in} the angular frequency of the noise frequency current are known.

It is assumed that the current value of the noise current measured before the conductor wire 4 is inserted into the two inductors is I ₀ , the current value when one inductor is inserted into the conductor wire is I ₁ , and an inductor is inserted into the conductor wire. When the current value at the time is I ₂ , the following equations (22), (23), and (24) are established.

Where Z _a = R _r + jX _a , Z _L = R _L + jX _L .

Seek their solution, then become

Where X ₁ 〉 X ₂ and α ₁

In this case, note that the 30 kHz noise current has a wavelength of 10 km, and the length of the conductor line 4 is much shorter than the wavelength, and the ground height is also small. Therefore, it is considered that the resistance value of R _r is 10 Ω or less, but in the case of a noise current of several tens of kHz which also flows several milliamperes, the value shown by the formula (25) becomes a problem. The reason is that the noise current overlapping with the conductor line 4 is not considered to be dependent on the radiation resistance of the antenna, but is considered to be caused by the near-noise magnetic field. If so, Rr can be used as an internal resistor of the oscillator.

(a) and (b) of Fig. 5 show the characteristic G of the noise attenuator using the embodiment of the present invention, and the characteristic G of the comparative example in which the noise attenuator is not used. It can be clearly seen from the (a) and (b) diagrams of Fig. 5 that, in the characteristic G of the comparative example, noise is prominent at 30 kHz, 50 kHz, 70 kHz, 90 kHz, 100 kHz to 200 kHz, etc., but through use. Regarding the noise attenuator of the embodiment of the present invention, it is known that noise is attenuated. From the actual measurement results, it can be understood that the noise attenuator of the embodiment of the present invention can purify the noise environment.

Further, in the embodiment of the present invention, as shown in Fig. 6, a parallel resonant circuit of the inductor 6 and the capacitor 7 may be disposed in front of the unit elements of the inductor 1 and the resistor 2, thereby suppressing the noise current more effectively.

According to the embodiment of the present invention, the noise current flowing through a conductor line such as a power supply line that supplies signal power from a signal power source to a load is a capacitor that does not cause a series resonance phenomenon, and can be circulated in a wiring form by using a resistor. The noise currents of different power lines, that is, the noise currents of the common mode and the normal mode, are consumed until the noise disturbance is suppressed, and the attenuation is overlapped to supply power from the power source or the signal source to the electronic device or The noise current on the signal line can purify the electromagnetic environment.

Specifically, in the noise filter disclosed in Patent Document 1, since the noise current in the normal mode is reflected in the capacitor and reflected toward the AC power source side, the noise current flows along the conductor on the AC power source side. The noise current is radiated from the conductor towards the surroundings, which causes a secondary obstacle.

In contrast, according to the embodiment of the present invention, as in the review of the effect of replacing the inductor with a pure resistor, the internal impedance of the conductor line as the antenna is Z _a = R _r + jX _a , which is connected to the conductor line. When the noise disturbance load impedance of the electronic device with noise disturbance is set to Z ₁ =R _L +jX _L , the resistance value R of the resistance is set to R. (X _a +X _L ) and the relationship of (R _r -R _L )≒R. Therefore, the noise current is consumed by the resistance in parallel with the inductor, and the retrograde power is such that the power of the noise current flowing through the conductor is as close as possible to zero, and the electromagnetic environment can be purified. This is an effect that cannot be achieved by the noise filter using a capacitor in Patent Document 1.

Further, in Patent Document 1, a countermeasure is proposed in which an inductor is inserted into a conductor wire to reduce noise disturbance. Signal transmission in a conductor line such as a signal line such as a power line is performed in a so-called normal mode. Conventionally, an inductor used for a noise filter of a power supply line is required to use a core material having high frequency response, but the core material has a drawback that magnetic saturation is likely to occur due to a low current value. Therefore, in the conventional noise filter, a structure is constructed, and in order to avoid magnetic saturation, two windings of the same number of turns are applied to one core material, and the magnetic fluxes are canceled by the reciprocating current. Therefore, the inductor in this case is effective only for the common mode noise current, and there is no countermeasure in the normal mode.

The line noise attenuator according to the embodiment of the present invention is configured to suppress the noise current of the common mode and the normal mode dual mode and has utility in noise power consumption, but is inserted toward the signal line, particularly toward the power line. In the case, it may become a problem that the magnetic saturation of the iron core material gives the limit of the effective current value.

Therefore, in the line noise attenuator according to the embodiment of the present invention, two or more inductors are connected in series, and resistors are connected in parallel to the inductors connected in series. Specifically, in the embodiment of the present invention, as shown in FIG. 1(b), the number of windings in one core material is set to a limit number which is magnetically saturated with a desired signal current value. The element in which the resistor 2 is connected in parallel in the inductor 1 is a unit element, and the unit elements are connected in series, and the total value of the inductances of the inductors connected in series is set as a composite inductance value, thereby suppressing the power supply. A case where a magnetic current is saturated due to a desired current of a line or the like. Therefore, the magnetic saturation phenomenon as in Patent Document 2 can be avoided, and the problem caused by the insertion of the resistor into the power supply line can be solved.

Magnetic saturation can be avoided by connecting two or more inductors in series, and magnetic saturation can be improved by using an inductor having a winding on a closed magnetic circuit forming core having a slit.

Furthermore, when the ratio of the inductance of the inductor to the resistance value of the resistor is fixed to a certain amount, and the inductor and the resistor are provided on the conductor line, the inductance of the ith inductor set to be connected in series is L _i The resistance value of the resistor is R _i , and the set noise lower limit angular frequency in the line noise attenuator is ω _n and R _i =ω _n L _i , so that the noise current does not flow through the inductor. The resistors connected in parallel are induced, and the noise is used to thermally consume the noise current.

Further, the internal impedance of the conductor line as the antenna is Z _a = R _r + jX _a , and the noise disturbance load impedance of the electronic device connected to the conductor line by the noise barrier is set to Z ₁ = R _L + jX _L , the resistance value R of the resistor is set to R Rr and R The relationship of ∣X _a +X _L ,, whereby the retrograde power can be made close to zero.

Further, the current value of the noise current measured before the conductor wire is inserted into the inductor is set to I0, and the current value when the conductor wire is inserted into one inductor is set to I1, and the current when the conductor wire is inserted into one inductor again The value is set to I2, and is calculated according to the following equation, whereby the impedance of the conductor line and the impedance of the noise disturbance load can be known, and can be correspondingly applied to different electromagnetic environments.

Further, the combination of the inductor and the resistor is balancedly connected on two conductor lines. As a result, the noise current superimposed on the conductor line such as the power supply line or the like acting as the linear antenna is consumed by the pure resistance in the unit of the conductor line, and the power consumption of the electronic device connected to the conductor line can be removed. Furthermore, the noise current is consumed by the resistor in units of conductor lines, and the re-radiation power from the conductor line acting as the linear antenna is reduced as much as possible, thereby purifying the noise electromagnetic environment.

According to the present invention, by attenuating noise currents superimposed on a line for supplying power or signals from a power source or a signal source to an electronic device, the electromagnetic environment can be cleaned, and the probability of occurrence of errors in the electronic device can be reduced.

1. . . Inductor

2. . . resistance

3. . . Signal power supply

4. . . Conductor wire

5. . . load

6. . . Inductor

7. . . Capacitor

A, B, C, D, E, F. . . Sampled data

G. . . Characteristics of the noise attenuator of the embodiment of the present invention

H. . . Characteristics of a comparative example that does not use a noise attenuator

Z _a , Z _L . . . Load impedance

T1, T2. . . Input

V _n . . . Noise voltage

I _n . . . Noise current and

E _n . . . Input voltage

Fig. 1(a) is a circuit diagram showing the configuration of a unit element of a line noise attenuator according to an embodiment of the present invention;

Fig. 1(b) is a circuit diagram showing an example in which unit elements shown in (a) of Fig. 1 are connected in series;

Fig. 2 is a circuit diagram in which the unit elements shown in Fig. 1(a) are arranged in a balanced manner on two conductor lines;

Fig. 3 is a view showing an electromagnetic environment measured in a state in which a noise attenuator according to an embodiment of the present invention is mounted;

Fig. 4 is a view showing an electromagnetic environment measured in a state in which a noise attenuator according to an embodiment of the present invention is mounted;

Figure 5 is a characteristic diagram showing the results of comparison between the embodiment of the present invention and a comparative example;

Figure 6 is a circuit diagram showing another embodiment of the present invention; and

Fig. 7 is a diagram showing an equivalent circuit in the case where the display conductor line is used as an antenna operation.

1. . . Inductor

2. . . resistance

and

4. . . Conductor wire

Claims (3)

A line noise attenuator is a line noise attenuator capable of attenuating noise in a current superimposed on a conductor line, the conductor line is derived from a low frequency signal power supply and connected to a load, and used as a transmitting and receiving high frequency noise The current is operated by an antenna, and includes: at least one inductor that allows low-frequency signal power to flow; and a parallel resistor that is set to flow in the inductor value of the angular frequency of the noise current The resistance value of the high-frequency noise current interrupted by the inductor is consumed by substituting the high-frequency noise current into heat by the resistance value thereof, wherein the internal impedance of the conductor line as the antenna is set to Z _a = R _r +jX _a , when the noise barrier load impedance of the electronic device connected to the conductor line is set to Z ₁ =R _L +jX _L , the resistance value R of the parallel resistor exists R>>(X _a +X _L ) And the relationship between (R _{r -} R _L ) ≒ R, the ratio of the inductance value of the inductor to the resistance value of the parallel resistor is a constant value. The line noise attenuator of claim 1, wherein the resistance value R of the parallel resistor has a relationship of R>>R _r and R>>| X _a +X _L |. The line noise attenuator according to claim 1, wherein two or more inductors are connected in series, and the parallel resistors are respectively connected in parallel to the inductors connected in series, before the conductor wires are inserted into the inductor The measured current value of the noise current is I ₀ , assuming that the current value of the inductor when the inductor is inserted into the conductor line is I ₁ and the current value of the inductor when the inductor is inserted into the conductor line is I ₂ , the following relationship exists Where R _{r is} used as the internal resistance of the transmitter, here, X ₁ > X ₂ , and