CN102332720A - The circuit noise attenuator - Google Patents

Abstract

The present invention discloses a kind of circuit noise attenuator; It can be with the circuit noise attenuator of the noise attentuation in the electric current that overlaps on the lead; This lead is by low frequency signal power supply derivation and connect a load; And, comprising an inductor as the antenna that the transmitting-receiving high frequency noise current is used, it allows the circulation of low frequency signal electric power; An and resistance; Inductance value with respect to this inductor in the angular frequency of noise current; Set the resistance value that can flow into for by the high frequency noise current of this inductor blocking; With its resistance value this high frequency noise current is replaced into heat consumption, the inductance value of this inductor is become certain value with the ratio of the resistance value of this resistance.This circuit noise attenuator does not use the capacitor that can cause the resonance series phenomenon, and utilizes resistance carrying out power consumption at the noise current that circulates on the different power line of distribution form up to till suppress noise.

Description

The circuit noise attenuator

Technical field

The present invention is relevant a kind of circuit noise attenuator, and the noise current that overlaps on the power supply signal line is done decay to purify electromagnetic environment.

Background technology

The overlapping noise current of lead with the earth connection that is connected electronic installation, power line etc. with the result of lead as the antenna start, makes the common mode electric current become main body.And, the lead of the power line that constitutes with these a little leads etc., its distribution form is different, and lead is changed connecting of direction, and a part that makes this lead produce the common mode electric current of discontinuity point is transformed into the normal mode electric current.

This noise muffler, in order to removing, to alleviate the common mode that is overlapped on the various leads and the caused obstacle of two noise currents of normal mode, and this kind noise muffler is disclosed in patent documentation 1.

The noise filter that patent documentation 1 is disclosed, it suppresses the constructor of covibration of the choke of usefulness in order to prevent capacitor that the normal mode noise remove is used and higher harmonic current.This noise muffler be through by the peak value that dwindles input current in the time of passing through of the input current of this choke lengthening lower frequency region to suppress higher harmonic component.Again, utilize this capacitor in the supply unit to absorb normal noise, though also at the noise of normal mode through capacitor and feedback line and towards the AC power lateral reflection.And, through by the resistance that is connected in parallel at this choke, to suppress choke and the caused resonance series phenomenon of capacitor.

And patent documentation 2 discloses the protective earth of both-end on a kind of earth connection that is installed in the different electronic installation of per 1 direct-to-ground capacitance and uses noise filter.

The noise filter that patent documentation 1 is disclosed; Be the problem person who surpasses the limiting value that satisfies specification because of caused the 17th time～the 23rd time higher harmonic current of the resonance series phenomenon of this capacitor and this choke in order to solve; Add resistance in the combination of its choke through suppressing usefulness by the capacitor of using at the normal mode noise remove and higher harmonic current, make the 17th time～the 23rd time higher harmonic current also improve and become below the limiting value.

Yet; Patent documentation 1 is fastened in the pass that suppresses the normal mode noise with capacitor; In the situation of common mode, because the voltage at capacitor two ends becomes identical voltage, so can not utilize capacitor to make short circuit to let high frequency noise current towards the AC power lateral reflection.

And though the resistance that on choke, is connected in parallel, this resistance is because be the resonance series phenomenon person who is used for suppressing with capacitor, so its resistance value is defined as to suppress the value of resonance series phenomenon.Though one when having current flowing on resistance; Really can produce power consumption because of this resistance; But its electric power consumption is setting person in order to suppress the resonance series phenomenon; Even if the normal mode noise flowing is crossed this resistance, because that this resistance value is suppressed to is lower, also not reaching needs noise current is carried out the degree of power consumption with the inhibiting value that suppresses the noise obstacle.

Moreover, in the patent documentation 1, obtain the inductance of choke and the resistance value of resistance according to measured data.Power line is as above-mentioned; It is different to be visualized as its distribution form, and owing to the configuration that is changed direction produces discontinuity point, and a part that has a common mode noise current is transformed into the formation of the situation of normal mode noise current; At noise current almost is the situation of common mode; With the mode of patent documentation 1, as above-mentioned, the voltage at the capacitor two ends becomes identical voltage; So the noise that can not carry out capacitor is caused is towards the AC power lateral reflection, and be difficult in response to the noise obstacle under common mode.

Again; Patent documentation 2 is the magnetic saturation persons that utilize inductor; And through by circulating in machine and causing that on machine the low-frequency current of the big current value of obstacle makes this inductor magnetic saturation; This low-frequency current is emitted ground connection with the protection machine, will with the overlapping little electric current of high-frequency noise of earth connection carry out heat loss person with the inductor parallel resistor.With the technology of this patent documentation 2 according to former state be used in the situation of electric power system; Because the current value at the low-frequency power electric current of the conductor of electric power system circulation is big; So inductor magnetic saturation; The high frequency noise current that is overlapped on the conductor is not receive to flow into machine under the inductor prevention, causes to let machine take place because of the caused obstacle of high frequency noise current.

Therefore, in the time of the technology of patent documentation 2 being built into the noise filter of electric power system, be necessary to change viewpoint is applicable to the noise filter of electric power system with establishment design theory.After the inductor investigation to actual productization, find not develop the inductor that has under the magnetic saturation in order to the required inductance value of prevention high frequency noise current not causing, and be necessary to develop the inductor that overcomes this problem again.

Summary of the invention

The object of the present invention is to provide a kind of circuit noise attenuator; It does not use the capacitor that can cause the resonance series phenomenon; And not because circulate on the conductor low-frequency singalling current and under the magnetic saturation; Utilize resistance to suppress, to carry out power consumption up to till remove obstacle in the noise current of the common mode of circulations such as the power line of identical distribution form.

For reaching this purpose; Relevant circuit noise attenuator of the present invention; Be that decay is overlapped in order to the noise current on the lead of supplying with signal electric power from the low frequency signal power supply towards load to purify the circuit noise attenuator of electromagnetic environment; The antenna that this lead is used as the transmitting-receiving high frequency noise current comes start, and comprises: inductor, and it allows the circulation of low frequency signal electric power; And resistance; Reactance value with respect to this inductor in the angular frequency of noise current; Set the resistance value that can flow into for by the high frequency noise current of this inductor blocking; With its resistance value this high frequency noise current is replaced into heat consumption, the ratio of the inductance of this inductor and the resistance value of this resistance is fixed into a certain amount of, have this inductor and this resistance on this lead.

According to the present invention; The just relevant lead noise current on the power line for example of supplying with signal electric power from signal power source towards load that circulates in; It is the capacitor that can cause the resonance series phenomenon not use; And not because low-frequency singalling current and under the magnetic saturation, though distribution homomorphosis or difference, all can be through the noise current at the common mode of circulations such as power line or holding wire is carried out power consumption with the removal obstacle.

Description of drawings

Fig. 1 (a) is the circuit diagram of formation of unit element of the circuit noise attenuator of relevant example of the present invention;

Fig. 1 (b) is the circuit diagram that shows the example that the unit element shown in Fig. 1 (a) is connected in series;

Fig. 2 is the circuit diagram that the unit element shown in Fig. 1 (a) is disposed on 2 leads evenly;

Fig. 3 is the figure that shows about the electromagnetic environment of measuring at the state of the noise muffler that is carrying the embodiment of the invention;

Fig. 4 is the figure that shows about the electromagnetic environment of measuring at the state of the noise muffler that is carrying the embodiment of the invention;

Fig. 5 is the performance plot that shows the result after the embodiment of the invention and comparative example are relatively;

Fig. 6 shows other the circuit diagram of embodiment of the present invention; And

Fig. 7 shows the figure of lead as the equivalent electric circuit in the situation of antenna.Among the figure

1: inductor; 2: resistance;

3: signal power source; 4: lead;

5: load; 6: inductor;

7: capacitor; A, B, C, D, E, F: sampled data;

G; The characteristic of the noise muffler of example of the present invention;

H; Do not use the characteristic of the comparative example of noise muffler;

Z _a, Z _L: load impedance; T1, T2: input;

V _n: noise voltage; I _n: noise current;

E _n: input voltage

Embodiment

Below, specify the embodiment of the invention according to drawing.

The basis of basic principle does in the embodiment of the invention, is conceived to the lead that is connected in electronic installation is come the result of usefulness as antenna, can become the situation of the principal element of the noise current of deriving.The present inventor adopts this antenna theory at first, does not have to launch this theoretical precedent.Below, reference literature J, D; Kraus " Antennas " translator: Gu Cungong, modern science society " antenna " is clear and 47 years version (document 1) go up the 49th page of volume and the black river row of holding concurrently; " microwave circuit is crossed the threshold ", ball kind (Co., Ltd.), clear and 38 years versions, the 34th page (document 2) explained.

With the overlapping noise current of lead of the earth connection that is connected in electronic installation, power line etc. do, come the result of usefulness as antenna, make the common mode electric current become main body with lead.And in the lead of the power line in the middle of these a little leads etc., its distribution form is different, and lead is changed connecting of direction, makes on the transmission path of this lead and produces discontinuity point, and the part of common mode electric current is transformed into the normal mode electric current.

So, a kind of noise muffler is proposed, it can be removed effectively, alleviate because of being overlapped in the caused obstacle of Bimodal Noise electric current on the various leads.

The lead that is connected in electronic installation is come the result of usefulness as antenna, and in the situation that is made as the principal element that becomes the noise current of deriving, its equivalent electric circuit is (document 1) as shown in Figure 7.This situation is got with the example of earth connection as lead, and a part that forms the lead of circuit is not lead but becomes ground connection.

Among Fig. 7, come the internal driving of the lead 4 of start to be made as Z as antenna _a=R _r+ jX _a, and the noise obstacle load impedance of the electronic installation that suffers the noise obstacle that is connected with lead 4 is made as Z _L=R _L+ jX _LIn this said noise obstacle load, refer to that electronic installation causes the imaginary load of the situation of obstacle because of noise current, it can't visual clearly, instrumentation, can be considered electronic circuit and parasitic capacitance between power line and resistance in the machine frame usually.In this situation, the energy that is consumed by the noise obstacle is replaced as a resistance, thus below only be called the obstacle load, with R _LBe made as the resistance deal that produces the power consumption of noise obstacle.

Now, in equivalent electric circuit shown in Figure 7, the input T1 before the electronic installation obstacle load of lead 4, the noise voltage among the T2 are made as V _n, noise current is made as I _n, when giving the amount of the following formula that becomes inferior converted quantity that belongs to these (document 2), as if being made as E towards input voltage as the lead 4 of antenna _n,

[numerical expression 2]

$a_n=\frac{V_n+I_n{Z}_a}{2\sqrt{\mathrm{ReZa}}}---\left(1\right)$

$a_n=\frac{V_n-I_n{Z_a}^{*}}{2\sqrt{\mathrm{ReZa}}}---\left(2\right)$

Then can know from Fig. 7

[numerical expression 3]

V _n＝E _n-Z _aI _n (3)

[numerical expression 4]

${\left|a_n\right|}^2=\frac{{{\mathrm{<figure-callout\; id="2"\; label="E\; n"\; filenames="HDA0000021807770000011.png,HDA0000021807770000021.png"\; state="\{\{state\}\}">E</figure-callout>}}_n}^2}{4R_r}---\left(4\right)$

(4) value represented of formula produces the maximum noise power value of noise problem.

(4) value shown in the formula is illustrated in the maximum noise power value (can change power value) that can be supplied in the obstacle load under the situation that leads such as the power line that is connected in electronic installation, earth connection play effectiveness as antenna.In other words, the value shown in (4) formula is that this lead can invest the maximum of electronic installation noise obstacle noise electric power from the maximum noise electric power of electromagnetic environment reception as antenna,

R _r=R _L, and X _a=-X _LSituation about setting up is supplied with and is given fault resistance (obstruction resistance) R _LNoise electric power.

And, at R _r=R _L, X _a=-X _LMatching condition under,

Because E _n-Z _aI _n=Z _LI _nSo, E _n=(Z _a+ Z _L) I _n, because Z _L=Z _a ^*So (2) formula becomes,

[numerical expression 5]

$\left|b_n\right|=\frac{V_n-I_n{Z_a}^{*}}{2\sqrt{\mathrm{ReZa}}}=\frac{E_n-(Z_n+{Z_a}^{*})I_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="HDA0000021807770000011.png,HDA0000021807770000021.png"\; state="\{\{state\}\}">n</figure-callout>}}}{2\sqrt{\mathrm{Re}{Z}_a}}=\frac{E_n-{\mathrm{<figure-callout\; id="2"\; label="E\; n"\; filenames="HDA0000021807770000011.png,HDA0000021807770000021.png"\; state="\{\{state\}\}">E</figure-callout>}}_n}{2\sqrt{\mathrm{Re}{Z}_a}}=0---\left(5\right)$

| b _n| ²Because be interpreted into the noise electric power that the lead 4 that is not used as antenna is received with this matching condition of obstacle load unmet as the lead of antenna 4, under this matching condition, show that its electric power is 0.That is, receive noise electric power all at the fault resistance R of electronic installation _LGo up by power consumption.

Now, use (1), (2) formula, try to ask (| a _n| ²-| b _n| ²) time, become

[numerical expression 6]

${\left|a_n\right|}^2={\left|b_n\right|}^2=\mathrm{Re}\left[V_n{I_n}^{*}\right]={\left|V_n\right|}^2\frac{R_L}{{R_L}^2+{X_L}^2}=\frac{(Z_a+{Z_a}^{*})(V_n{I_n}^{*}+{V_n}^{*}I)}{4R_r}$

$=\frac{{E_n}^2{R}_L}{{(R_r+X_L)}^2+(X_a+X_L)}=W_{\mathrm{nL}}---\left(6\right)$

, W _NLBe illustrated in the consumes electric power that the obstacle load resistance can consume in the common state (state does not match).

What is called alleviates the caused obstacle of noise electric power, and expression means the right W with (6) formula _NLLower, and see through insertion inductor on circuit and plot W _NLAttenuating.

In the past, in the 4 terminal type filters that the noise filter as power line uses, being construed as inductor only had effectiveness (with reference to patent documentation 1) to the common mode noise current.This with the denominator of (6) formula ( X _a + X _L ) add to have and become

X _f =ω _n LThe angular frequency reactance deal (inductor) that increases characteristic be identical function.At this, ω _nBe the angular frequency of noise current, L is the inductance of inductor.

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

[numerical expression 7]

${\left|a_n\right|}^2-{\left|b_n^{\&prime;}\right|}^2=\frac{{E_n}^2{R}_L}{{(R_r+R_L)}^2+{(X_a+X_L+X_f)}^2}=W_{\mathrm{nL}}^{\&prime;}---\left(7\right)$

In order to satisfy W ' _NL＜W _NL, must (X _a+ X _L+ X _f) ²＞(X _a+ X _L) ², therefore, at (X _a+ X _L) be capacitive situation, be necessary that employing can become X _f＞-2 (X _a+ X _L) such X _fInductor just.

When use is to become X towards the inductor that lead inserts _f＜-2 (X _a+ X _L) during such inductor, owing to can cause W ' _NL＞W _NL, this is become have and causes the so-called regurgitation effect problem that consumes electric power is increased because of the obstacle load resistance.

On the other hand, in (6), (7) formula | b _n| ²With | b ' _n| ²Become

[numerical expression 8]

${\left|b_n\right|}^2=\frac{{{\mathrm{<figure-callout\; id="2"\; label="E\; n"\; filenames="HDA0000021807770000011.png,HDA0000021807770000021.png"\; state="\{\{state\}\}">E</figure-callout>}}_n}^2}{4R_r}\frac{{(R_r-R_L)}^2+{(X_a+X_L)}^2}{{(R_r+R_L)}^2+{(X_a+X_L)}^2}---\left(8\right)$

, with respect to X _f→ ∞ becomes

[numerical expression 9]

${\left|b_n^{\&prime;}\right|}^2=\frac{{{\mathrm{<figure-callout\; id="2"\; label="E\; n"\; filenames="HDA0000021807770000011.png,HDA0000021807770000021.png"\; state="\{\{state\}\}">E</figure-callout>}}_n}^2}{4R_r}\frac{{(R_r-R_L)}^2+{(X_a+X_f+X_L)}^2}{{(R_r+R_L)}^2+{(X_a+X_f+X_L)}^2}$

$=\frac{{{\mathrm{<figure-callout\; id="2"\; label="E\; n"\; filenames="HDA0000021807770000011.png,HDA0000021807770000021.png"\; state="\{\{state\}\}">E</figure-callout>}}_n}^2}{4R_r}\frac{{\left(\frac{R_r-R_L}{X_f}\right)}^2+{(\frac{X_a+X_L}{X_f}+1)}^2}{{\left(\frac{R_r+R_L}{X_f}\right)}^2+{(\frac{X_a+X_L}{X_f}+1)}^2}---\left(9\right)$

, | b ' _n| ²Receiving electric power almost becomes via lead (feedback line) and feeds back the retrograde electric power in mains side.

Try to ask again, (| b ' _n| ²-| b _n| ²) afterwards, become

[numerical expression 10]

${\left|b_n^{\&prime;}\right|}^2-{\left|b_n\right|}^2=\frac{{{\mathrm{<figure-callout\; id="2"\; label="E\; n"\; filenames="HDA0000021807770000011.png,HDA0000021807770000021.png"\; state="\{\{state\}\}">E</figure-callout>}}_n}^2}{4R_r}\{\frac{{(R_r-R_L)}^2+{(X_a+X_L+X_f)}^2}{{(R_r+R_L)}^2+{(X_a+X_L+X_L)}^2}-\frac{{(R_r-R_L)}^2+{(X_a+X_L)}^2}{{(R_r+R_L)}^2+{(X_a+X_L)}^2}\}$

$=\frac{{E_n}^2{R}_L{X}_f(2X_a+2X_L+X_f)}{\{{(R_r+R_L)}^2+{(X_a+X_L+X_f)}^2\}\{{(R_r+R_L)}^2+{(X_a+X_L)}^2\}}---\left(10\right)$

, at (X _a+ X _L) when being capacitive character, because at X _f＞-2 (X _a+ X _L) condition under be to become | b ' _n| ²＞| b _n| ²So expression is through the increase of the electric power (inverse power) that drives in the wrong direction, obstacle electric power can reduce.

In this external (8) formula, if be taken at the R of antenna match condition _r=R _L, X _a=-X _L, then | b _n| ²Become 0, do not become drive in the wrong direction electric power or radiation electric power again as the maximum noise electric power that receives of the situation of antenna performance function at lead 4, consistent with the result of (5) formula.

Noise obstacle according to insert from inductor to various lead 4 lowers countermeasure, also has as this minus effect, and only causes the increase of the electric power that drives in the wrong direction, the effect that the electromagnetic environment of also not deriving purifies.

So, examine with regard to the effect that inductor is replaced as the situation of pure resistance at this.That is, if ω _nL R is to become equivalence in the situation that inductor is replaced as pure resistance then,

[numerical expression 11]

${\left|a_n\right|}^2-{\left|b_n^{\&prime;\&prime;}\right|}^2=\frac{{E_n}^2(R+R_L)}{{(R_r+R_L+R)}^2+{(X_a+X_L)}^2}$

$=\frac{{E_n}^{2}R}{{(R_r+R_L+R)}^2+{(X_a+X_L)}^2}+\frac{{E_n}^2{R}_L}{{(R_r+R_L+R)}^2+{(X_a+X_L)}^2}$

$=W_{\mathrm{nR}}+W_{\mathrm{nL}}^{\&prime;\&prime;}---\left(11\right)$

If compare with (7) formula, the existence according to resistance R obviously becomes

W " _NL＜W _NL, at obstacle load resistance R _LConsumes electric power lowered.The retrograde electric power of this situation becomes,

[numerical expression 12]

${\left|a_n\right|}^2-{\left|b_n^{\&prime;\&prime;}\right|}^2=\frac{{{\mathrm{<figure-callout\; id="2"\; label="E\; n"\; filenames="HDA0000021807770000011.png,HDA0000021807770000021.png"\; state="\{\{state\}\}">E</figure-callout>}}_n}^2}{4R_r}\frac{{(R_r-R_L-R)}^2+{(X_a+X_L)}^2}{{(R_r+R_L+R)}^2+{(X_a+X_L)}^2}$

$=\frac{{{\mathrm{<figure-callout\; id="2"\; label="E\; n"\; filenames="HDA0000021807770000011.png,HDA0000021807770000021.png"\; state="\{\{state\}\}">E</figure-callout>}}_n}^2}{4R_r}\frac{{(\frac{R_r-R_L}{R}-1)}^2+{\left(\frac{X_a+X_L}{R}\right)}^2}{{(\frac{R_r+R_L}{R}+1)}^2+{\left(\frac{X_a+X_L}{R}\right)}^2}---\left(12\right)$

, if with can become R＞＞(X _a+ X _L) and

Mode select the value of parallel resistance R, then | b ' _n| ²Become infinitely small, the electric power that drives in the wrong direction is near 0.

Again, with inductor X _fBe replaced as resistance R, with X _f=R asks

(| b ' _n| ²-| b " _n| ²) time, become

[numerical expression 13]

${\left|b_n^{\&prime;}\right|}^2-{\left|b_n^{\&prime;\&prime;}\right|}^2=\frac{{{\mathrm{<figure-callout\; id="2"\; label="E\; n"\; filenames="HDA0000021807770000011.png,HDA0000021807770000021.png"\; state="\{\{state\}\}">E</figure-callout>}}_n}^2}{4R_r}\{\frac{{(R_L-R_r)}^2+{(X_a+X_L+X_f)}^2}{{(R_L+R_r)}^2+{(X_a+X_L+X_f)}^2}-\frac{{(R+R_L-R_r)}^2+{(X_a+X_L)}^2}{{(R+R_L+R_r)}^2+{(X_a+X_L)}^2}\}$

$={E_n}^2\frac{R\{{R_r}^2-{{\mathrm{<figure-callout\; id="2"\; label="R\; L"\; filenames="HDA0000021807770000011.png,HDA0000021807770000021.png"\; state="\{\{state\}\}">R</figure-callout>}}_L}^2+{(X_a+X_L+X_f)}^2\}+R_L\{{{\mathrm{<figure-callout\; id="2"\; label="X\; f"\; filenames="HDA0000021807770000011.png,HDA0000021807770000021.png"\; state="\{\{state\}\}">X</figure-callout>}}_f}^2+2(X_a+X_L)X_f-R^2\}}{\{{(R_r+R_L)}^2+{(X_a+X_L+X_f)}^2\}\{{(R_L+R_r+R)}^2+{(X_a+X_L)}^2\}}$

$=\frac{{E_n}^2}{R}\frac{{\left(\frac{R_r}{R}\right)}^2-{\left(\frac{R_L}{R}\right)}^2+{(1+\frac{X_a+X_L}{R})}^2+2\left(\frac{R_L}{R}\right)\left(\frac{X_a+X_L}{R}\right)}{\{{\left(\frac{R_r+R_L}{R}\right)}^2+{(1+\frac{X_a+X_L}{R})}^2\}\{{(1+\frac{R_r+R_L}{R})}^2+{\left(\frac{X_a+X_L}{R}\right)}^2\}}---\left(13\right)$

, if R＞＞R _L, R _rAnd R|X _a+ X _L|, then become

[numerical expression 14]

$({\left|b_n^{\&prime;}\right|}^2-{\left|b_n^{\&prime;\&prime;}\right|}^2)=\frac{{E_n}^2}{R}>0$

So the part of expression noise electric power is consumed by resistance R, compared with inductor X _f, drive in the wrong direction electric power that is again radiation electric power more lowered.This attenuating degree is interdependent with (12) formula.

In embodiments of the present invention, verified to see through inductor is replaced as pure resistance, can lower the noise obstacle electric power in the electronic installation and the electric power that drives in the wrong direction.Yet, power line be asked to be easy to the to circulate signal code of set supply frequency etc.Holding wire particularly, owing to need the signal code of the set frequency of circulation, so can not only resistance be inserted lead.

So; In the embodiment of the invention; In the power line as the genus lead 4 of antenna shown in Fig. 1 (a), fundamental frequency electric current (low-frequency singalling current) circulated easily and give power consumption to high frequency noise current makes the formation of simple circuit element that is difficult to circulate use as basic comprising.That is the embodiment of the invention is shown in Fig. 1 (a), and be connected in parallel inductor 1 and resistance 2 are construed as the simplest circuit element with it.

If make shown in Fig. 1 (a), can determine the inductance L of inductor 1, the resistance value R of resistance 2, make the supply frequency electric current (low-frequency singalling current) that is in lower frequency region logical at inductor 1 effluent, the noise current (high frequency noise current) that is in high-frequency domain is logical at resistance 2 effluents.For example, the inductance L of inductor 1 is made as 10mH, when the resistance value R of resistance 2 is made as 50 Ω; Electric current (low-frequency singalling current) for supply frequency 50Hz; Because the reactance of inductor 1 is 3 Ω, so 50 Ω＞＞3 Ω, the supply frequency electric current almost is logical at inductor 1 effluent.On the other hand, with the high frequency noise current of 10KHz, the reactance of inductor 1 approximately is 630 Ω, and this high frequency noise current is almost logical and by power consumption at resistance 2 effluents.Therefore, can at last with to the high frequency noise current more than the 10KHz inductor 1 be replaced as the pure resistance equivalence.

The embodiment of the invention is with 2 power lines of the insertion of the basic circuit shown in Fig. 1 (a) and with noise muffler practicability.

Signal in the lead 4 as the power line equisignal line transmits, and carries out according to so-called normal mode.In the past, the inductor of the noise filter that power line is used was necessary the material unshakable in one's determination that uses high frequency response property high, but should have the shortcoming that magnetic saturation takes place because of low current value easily by the iron core material.So noise filter in the past is construed as: on 1 material unshakable in one's determination, impose the coiling of 2 identical numbers of turn for avoiding magnetic saturation, magnetic flux is cancelled out each other by reciprocal electric current.Therefore, the inductor of this situation only becomes has effectiveness to the common mode noise current.

Though be the thing that reaches described in Ba Lun (Balun) circuit of antenna engineering; But just want to supply power to wire antenna at normal mode at last, the situation that the part that the discontinuity point of the transmission lines that produces at the connecting portion with antenna can cause the normal mode electric current is transformed into common mode is intelligible.Therefore, that side who connects at power line (lead 4) owing to making the discontinuity point of direction transformation etc. squarely, has the part of a lot of common mode noise currents to be transformed into the situation of normal mode, and patent documentation 1 also is not have effectiveness.

The circuit noise attenuator of the relevant embodiment of the invention can suppress the noise current of common mode, normal mode bimodulus effectively and consume noise electric power; But be inserted in the situation that holding wire particularly is inserted in power line; What can become problem points is, causes the magnetic saturation of this iron core material to invest the limit of effective current value.

So; The circuit noise attenuator of the relevant embodiment of the invention; Make a coiling number in the material unshakable in one's determination and terminate in the limit number of turn at desired signal current value meeting magnetic saturation; Be made as unit element to the element of parallelly connected combined resistance 2 on this inductor 1, with the practicability of attempting expectation current noise attenuator that can anti-power line etc.In addition, the limit number of turn of meeting magnetic saturation is determined by the current value that circulates in lead, and not exclusive decision maker, adjusts in response to current value.

About the circuit noise attenuator of the embodiment of the invention the be connected in parallel inductor 1 shown in Fig. 1 (a) and resistance 2 and make unit element, the array (series connection) that these unit element is carried out shown in Fig. 1 (b) connects.Moreover, make the inductance L of this inductor 1 _i(L ₁, L ₂, L ₃... L _n) with the resistance value R of this resistance 2 _i(R ₁, R ₂R _n) ratio be fixed into a certain amount of.

If the impedance of i unit element is made as Z among Fig. 1 (b) _i, then show

[numerical expression 15]

$Z_i=\left|Z_i\right|e^{j{\mathrm{\&theta;}}_i}---\left(14\right)$ At this,

[numerical expression 16]

$\left|Z_i\right|=\frac{R_i\left(\mathrm{\&omega;}{L}_i\right)}{\sqrt{{{\mathrm{<figure-callout\; id="2"\; label="R\; i"\; filenames="HDA0000021807770000011.png,HDA0000021807770000021.png"\; state="\{\{state\}\}">R</figure-callout>}}_i}^2+{\left(\mathrm{\&omega;}{L}_i\right)}^2}}---\left(15\right)$

${\mathrm{\&theta;}}_i=\arctan \frac{R_i}{\mathrm{\&omega;}{L}_i}---\left(16\right)$

Therefore, the composite impedance Z of the unit element more than 2 that is connected in series with power line (lead 4) becomes

[numerical expression 17]

$Z=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\left|Z_i\right|e^{j{\mathrm{\&theta;}}_i}---\left(17\right)$

At this, if be set as

[numerical expression 18]

${\mathrm{\&theta;}}_1={\mathrm{\&theta;}}_2=\&CenterDot;\&CenterDot;\&CenterDot;={\mathrm{\&theta;}}_i=\&CenterDot;\&CenterDot;\&CenterDot;={\mathrm{\&theta;}}_n=\mathrm{\&theta;}---\left(18\right)$

Then become

[numerical expression 19]

$Z=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\left|Z_i\right|e^{\mathrm{j\&theta;}}---\left(19\right)$

To the angular frequency of noise current arbitrarily, if R _i/ ω L _i=x,

(19) formula becomes

[numerical expression 20]

$Z=\frac{e^{\mathrm{j\&theta;}}}{\sqrt{1+x^2}}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{R}_i---\left(20\right)$

In this situation, with ω as the expectation noise lower limit angular frequency in the noise muffler _n, if can become R _i/ ω _nL _i=x=1 that is R _i=ω _nL _iMode set R _iWith L _iValue, (20) formula becomes

[numerical expression 21]

$Z=\frac{e^{j\frac{\mathrm{\&pi;}}{4}}}{\sqrt{2}}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{R}_i---\left(21\right)$

Therefore, setting the also high noise angle frequency of lower limit noise angle frequency than this ω L _i R _i , thereby become x → 0,

[numerical expression 22]

$Z\&RightArrow;\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{R}_i$

At this, the inductance L of so-called inductor 1 _i(L ₁, L ₂L _n) with resistance value Ri (R1, the R2 of resistance 2 ... Rn) ratio is fixed into a certain amount of, means that ω is made as the expectation noise lower limit angular frequency in the noise muffler _n, can become R _i/ ω _nL _i=x=1 that is R _i=ω _nL _iMode set R _iAnd L _iValue.In addition, R _iSystem means it is the resistance 2 in i the unit element that shown in Fig. 1 (b), is connected in series _iResistance value, L _iThen mean it is the inductor 1 in i the unit element that shown in Fig. 1 (b), is connected in series _iInductance.

At this, take one with the example of power line with noise muffler practicability.Be to use up to still undersaturated inductor 1 till the maximum current 10A, the ferrite ring-type coil of inductance that will have 0.4mH is as inductor 1.When effective lower limit noise frequency is made as 10kHz, R _i=25 Ω.If establishing this unit element respectively uses 3 inductors 1 on 2 power lines, then become ∑ R _i=150 Ω.In the situation that to establish effective lower limit noise frequency be 50kHz, establish R again, _i=125 Ω, total resistance value become 750 Ω.

Again, as shown in Figure 2 in the embodiment of the invention, owing to also can consume retrograde electric power, let the circuit element shown in Fig. 1 (b) on 2 leads 4, lead 4, connect evenly.Fig. 2 also comprises signal power source 3 and load 5.In addition, among Fig. 2, lead is made 2 line formulas, but do not receive this limit, also can be 3 line formulas.

The circuit noise attenuator of the relevant embodiment of the invention guides into power consumption to overlapping noise current on as the lead of the for example power line of wire antenna etc. by pure resistance, removes the noise obstacle of the electronic installation that is connected to lead.In this situation, the noise obstacle of removing in this electronic installation gets final product, and must will be increased to more than the essential value with the resistance value of inductor 1 parallel resistor 2.Another purpose of the circuit noise attenuator of relevant example of the present invention is, sees through with the resistance consumption noise current and lowers the electric power of radiation again that comes from as the wire antenna lead as far as possible to purify the noise electromagnetic environment.

For this reason, be necessary to know impedance Z as the lead 4 of wire antenna shown in Figure 6 _aWith impedance Z as the load of noise current load _LValue.Though there is no need correctly to know these value, see through and know general value, can determine the constant of circuit noise attenuator.So, below to knowing this X in the electronic installation that receives the noise obstacle _aWith Z _LThe means of value examine.

Fig. 3 and Fig. 4 are shown as the constant of decision noise muffler and utilize pincers type galvanometer on the earth connection that is connected in a large-scale electronic installation to survey the example of noise current frequency spectrum.Fig. 3 and Fig. 4 represent to electromagnetic environment in the overlapping noise current of set various earth connection make sampled data A, B, C, D, the E after the actual measurement, the frequency spectrum of F.In Fig. 3 and Fig. 4, its transverse axis is got frequency (kHz), and longitudinal axis power taking flow valuve (dB μ A) is to show frequency spectrum.Among Fig. 3, be presented at the frequency spectrum of sampled data A under frequency 10kHz～100kHz, B, C, among Fig. 4, be presented at the frequency spectrum of sampled data D under frequency 0.1MHz～1MHz, E, F.Can know understanding by Fig. 3, be presented at the frequency spectrum size miscellaneous of the noise current below the 100kHz, the noise current frequency that in fact mainly becomes the noise barrier factors is not clear.But, think that the maximum current amplitude of noting noise current is to conform with convention, note the 30kHz noise current among Fig. 3.When the noise current of this 30kHz is carried out power consumption and removal and become the electronic installation noise obstacle of object by the circuit noise attenuator of the relevant embodiment of the invention, be necessary to know impedance Z as the lead 4 of wire antenna _aAnd the impedance Z of noise obstacle load _LSize.

In the impedance Z that will know lead 4 _aAnd the impedance Z of noise obstacle load _LBig or small the time, used the mensuration of 2 inductors.Now, the inductance of establishing 2 inductors is respectively L ₁, L ₂And its inductance value is known, then notes the reactance value X in the angular frequency of noise frequency electric current ₁, X ₂Known.

If establishing the current value that inserts the noise current of being measured before 2 inductors towards lead 4 is I ₀, the current value when establishing 1 inductor and having inserted lead is I ₁, and establish that to insert the current value of an inductor when lead again be I ₂The time, then set up time formula (22), (23), (24).

[numerical expression 23]

$\left|I_0\right|=\frac{\left|E_n\right|}{\sqrt{{(X_a+X_L)}^2+{(R_r+R_L)}^2}}---\left(22\right)$

$\left|I_1\right|=\frac{\left|E_n\right|}{\sqrt{{(X_a+X_L+X_1)}^2+{(R_r+R_L)}^2}}---\left(22\right)$

$\left|I_2\right|=\frac{\left|E_n\right|}{\sqrt{{(X_a+X_L+X_2)}^2+{(R_r+R_L)}^2}}---\left(24\right)$

Z wherein _a=R _r+ jX _a, Z _L=R _L+ jX _L

Ask it to separate, then become

[numerical expression 24]

$X_a+X_L=\frac{{\mathrm{\&alpha;}}_1{{\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="HDA0000021807770000011.png,HDA0000021807770000021.png"\; state="\{\{state\}\}">X</figure-callout>}}_2}^2-{\mathrm{\&alpha;}}_2{{\mathrm{<figure-callout\; id="1"\; label="X"\; filenames="HDA0000021807770000011.png,HDA0000021807770000041.png"\; state="\{\{state\}\}">X</figure-callout>}}_1}^2}{2({\mathrm{\&alpha;}}_2{X}_1-{\mathrm{\&alpha;}}_1{X}_2)}---\left(25\right)$

$R_r+R_L=\frac{\sqrt{4X_1{X}_2(X_1-X_2)({\mathrm{\&alpha;}}_1{X}_2-{\mathrm{\&alpha;}}_2{X}_1)-{({\mathrm{\&alpha;}}_1{{\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="HDA0000021807770000011.png,HDA0000021807770000021.png"\; state="\{\{state\}\}">X</figure-callout>}}_2}^2-{\mathrm{\&alpha;}}_2{{\mathrm{<figure-callout\; id="1"\; label="X"\; filenames="HDA0000021807770000011.png,HDA0000021807770000041.png"\; state="\{\{state\}\}">X</figure-callout>}}_1}^2)}^2}}{2({\mathrm{\&alpha;}}_1{X}_2-{\mathrm{\&alpha;}}_2{X}_1)}---\left(26\right)$

Wherein, X ₁＞X ₂, and

With this example, note the noise current of 30kHz, its wavelength is 10km, the length of lead 4 is also short more than wavelength, and ground Gao Yixiao.Therefore, can think R _rResistance value be below 10 Ω, but in the noise current situation of tens of kHz of the number milliampere that also circulates, how the value shown in (25) formula is to become problem if can becoming.Reason is, do not think with overlapping noise current and the antenna radiation resistance of this lead 4 interdependently, but thinks cause due to the noise magnetic field nearby.If like this, the internal resistance use that Rr becomes as oscillator gets final product.

Fig. 5 (a) and (b) show the relevant characteristic H that uses the noise muffler of the embodiment of the invention, with the characteristic G of the comparative example that does not use noise muffler.Can know understanding by Fig. 5 (a) and (b),, have noise outstanding at 30kHz, 50kHz, 70kHz, 90kHz, 100kHz～200kHz etc., but see through the noise muffler that uses the relevant embodiment of the invention, can know in the noise attentuation with the characteristic G of comparative example.Measured result thus, the noise muffler that can understand example of the present invention can purify noise circumstance.

Again, the embodiment of the invention is as shown in Figure 6, also can make at inductor 1 and the leading portion configuration inductor 6 of the unit element of resistance 2 and the tank circuit of capacitor 7, more effectively to suppress noise current.

According to the embodiment of the invention; The just relevant lead noise current on the power line for example of supplying with signal electric power from signal power source towards load that circulates in; Not use the capacitor that can cause the resonance series phenomenon; And can will circulate in the noise current of different power line of distribution form etc. that is the noise current of common mode and normal mode carries out power consumption with resistance; Up to till suppress the noise obstacle, overlap the noise current on being used for from power supply or signal source towards the circuit of electronic installation supply capability or signal and can purify electromagnetic environment by decay.

Particularly; In the noise filter that patent documentation 1 is disclosed, because the noise current that makes normal mode is circuitous and towards the AC power lateral reflection at capacitor, thereby noise current is logical at the AC power effluent along conductor; Towards radiation more on every side, this can cause the secondary obstacle to noise current from conductor.

Relatively, such according to the embodiment of the invention as the self-criticism that the effect that is replaced as with regard to inductor behind the pure resistance is done, be made as Z as the lead internal driving of antenna _a=R _r+ jX _a, the noise obstacle load impedance of the electronic installation that suffers the noise obstacle that is connected with this lead is made as Z ₁=R _L+ jX _LThe time, with the resistance value R of this resistance be set as R＞＞(X _a+ X _L) and

Relation.Therefore, noise current quilt and inductor parallel resistor heat loss, retrograde electric power also can make electric power that noise current circulates in conductor as much as possible near 0, can purify electromagnetic environment.This be as patent documentation 1 used capacitor noise filter the effect that can't reach.

In the patent documentation 1, impose towards lead and insert the countermeasure of inductor with the reducing noise obstacle again.Signal in the lead as the power line equisignal line transmits, and carries out according to so-called normal mode.In the past, the inductor that is used to the noise filter of power line was necessary the material unshakable in one's determination that uses high frequency response property high, but should have the shortcoming that magnetic saturation takes place because of low current value easily by the iron core material.So, be construed as in the noise filter in the past, impose the coiling of 2 identical numbers of turn for avoiding magnetic saturation at 1 material unshakable in one's determination, utilize reciprocal electric current that magnetic flux is cancelled out each other.Therefore, the inductor of this situation only becomes has effectiveness to the common mode noise current, under normal mode, does not have countermeasure.

The circuit noise attenuator of the relevant embodiment of the invention; Suppress the noise current of common mode, normal mode bimodulus and in noise power consumption, have effectiveness; But; In situation about particularly inserting towards power line towards holding wire, what can become problem points is, causes the magnetic saturation of this iron core material to give the limit of effective current value.

So, the circuit noise attenuator of the relevant embodiment of the invention, the inductor more than 2 of being connected in series, and the resistance that is connected in parallel respectively on each inductor after this is connected in series.Particularly; In embodiments of the present invention, shown in Fig. 1 (b), the coiling number in 1 material unshakable in one's determination make can magnetic saturation with expectation signal code value the limit number of turn; Be made as unit element to the element of parallelly connected combined resistance 2 on this inductor 1; This unit element is connected in series, and the value after the inductance value of the inductor of its number that is connected in series is added up to is made as compound inductance value, thereby can suppress to produce because of the expectation electric current of power line etc. the situation of magnetic saturation.Therefore, can avoid the magnetic saturation phenomenon as patent documentation 2, can solve resistance and insert the caused problem of power line.

Inductor by being connected in series more than 2 can be avoided magnetic saturation, moreover, by use the inductor that coiling is arranged on the closed magnetic circuit with slit forms with iron core, can promote anti-magnetic saturation property.

Moreover, be to be fixed into a certain amount ofly at the ratio of the inductance of this inductor and the resistance value of this resistance, and when having this inductor with this resistance on this lead, the inductance of setting i the inductor that is connected in series for is L _i, the resistance value of resistance is R _i, setting the noise lower limit angular frequency in the circuit noise attenuator is ω _n, and R=ω _nL _iRelation, can make noise current not flow through inductor and be induced to the resistance that is connected in parallel, utilize resistance that noise current is carried out heat loss.

Again, the lead internal driving as antenna is made as Z _a=R _r+ jX _a, the noise obstacle load impedance of the electronic installation that suffers the noise obstacle that is connected with this lead is made as Z ₁=R _L+ jX _L, with the resistance value R of this resistance be set as R＞＞Rr and R|X _a+ X _L| relation, can make the electric power that drives in the wrong direction near 0.

Again; Current value when the current value of the noise current of being measured before the lead insertion inductor is made as IQ in 1 inductor of lead insertion is made as I1, the current value when lead inserts an inductor again is made as I2 again; Calculate according to following formula; Can know the impedance magnitude of the impedance and the load of noise obstacle of lead, also can be corresponding in the same manner to different electromagnetic environments.

[numerical expression 25]

$X_a+X_L=\frac{{\mathrm{\&alpha;}}_1{{\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="HDA0000021807770000011.png,HDA0000021807770000021.png"\; state="\{\{state\}\}">X</figure-callout>}}_2}^2-{\mathrm{\&alpha;}}_2{{\mathrm{<figure-callout\; id="1"\; label="X"\; filenames="HDA0000021807770000011.png,HDA0000021807770000041.png"\; state="\{\{state\}\}">X</figure-callout>}}_1}^2}{2({\mathrm{\&alpha;}}_2{X}_1-{\mathrm{\&alpha;}}_1{X}_2)}$

[numerical expression 26]

$R_r+R_L=\frac{\sqrt{4X_1{X}_2(X_1-X_2)({\mathrm{\&alpha;}}_1{X}_2-{\mathrm{\&alpha;}}_2{X}_1)-{({\mathrm{\&alpha;}}_1{{\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="HDA0000021807770000011.png,HDA0000021807770000021.png"\; state="\{\{state\}\}">X</figure-callout>}}_2}^2-{\mathrm{\&alpha;}}_2{{\mathrm{<figure-callout\; id="1"\; label="X"\; filenames="HDA0000021807770000011.png,HDA0000021807770000041.png"\; state="\{\{state\}\}">X</figure-callout>}}_1}^2)}^2}}{2({\mathrm{\&alpha;}}_1{X}_2-{\mathrm{\&alpha;}}_2{X}_1)}$

Being combined on 2 leads of this inductor and this resistance is connected evenly again.To be overlapped in as wire antenna with lead unit and to come the noise current pure resistance on the lead of for example power line etc. of usefulness to cause into power consumption, and can remove the noise obstacle of the electronic installation that is connected to lead.Moreover, utilizing the resistance consumption noise current with lead unit, attenuating comes from the electric power of radiation again as the lead of wire antenna as far as possible, can purify the noise electromagnetic environment.

Claims (5)

1. circuit noise attenuator; It can be with the circuit noise attenuator of the noise attentuation in the electric current that overlaps on the lead; This lead is derived by a low frequency signal power supply and is connected a load, and an antenna of using as the transmitting-receiving high frequency noise current comes start, it is characterized in that: comprise:

One inductor, it allows the circulation of low frequency signal electric power; And

One resistance; Inductance value with respect to this inductor in the angular frequency of noise current; Set the resistance value that can flow into for by the high frequency noise current of this inductor blocking; With its resistance value this high frequency noise current is replaced into heat consumption, the inductance value of this inductor is become certain value with the ratio of the resistance value of this resistance.

2. circuit noise attenuator as claimed in claim 1 is characterized in that: the said inductor more than 2 of being connected in series, said resistance is connected in parallel respectively on each inductor that is connected in series.

3. circuit noise attenuator as claimed in claim 2 is characterized in that: said inductor is on the iron core of the closed magnetic circuit institute construction with space, to wind the line to form.

4. circuit noise attenuator as claimed in claim 1 is characterized in that: the inductance value of setting i the said inductor that is connected in series for is Li, and the resistance value of said resistance is Ri, and the setting noise lower limit angular frequency in the circuit noise attenuator is ω _n, and R _i=ω _nL _i

5. circuit noise attenuator as claimed in claim 1 is characterized in that: the internal driving as the lead of said antenna is made as Z _a=R _r+ jX

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