CN104020336B - Method for estimating crosstalk voltage of wire in direct-current circuit with difference-module excitation source - Google Patents

Abstract

The invention belongs to the field of crosstalk of transmission wire harness in electromagnetic compatibility and particularly relates to a method for estimating crosstalk voltage of a wire in a direct-current circuit with a difference-module excitation source. According to the method for estimating the crosstalk voltage of the wire in the direct-current circuit with the difference-module excitation source, the interval between every two adjacent wires is measured and the distances between wires and the ground are measured according to the arrangement relation between all the wires, the wire 1 and the wire 2 are crosstalk application difference-module circuit lines, and the wire 3 is a crosstalk receiving wire; the self-capacitance per unit length, the self-inductance per unit length, the mutual capacitance per unit length and the mutual inductance per unit length between every two adjacent wires are obtained according to the method of images; a model for estimating the crosstalk voltage in the wire of the alternating-current circuit with the difference-module excitation source is established according to the inductance values and the capacitance values; a three-conductor transmission line equation is obtained according to the Kirchhoff law; the crosstalk voltage and the crosstalk current on the crosstalk receiving wire are obtained. By the adoption of the method for estimating the crosstalk voltage of the wire in the direct-current circuit with the difference-module excitation source, estimating and measurement of the crosstalk between the wires when the wires of the system are arranged according to the arrangement relation can be achieved easily and rapidly, resources are saved, and the application range is wide.

Description

A kind of ac circuit with differential mode driving source is estimated to wire crosstalk voltage in loop Method

Technical field

The invention belongs in electromagnetic compatibility transmission line wire harness crosstalk field and in particular to be a kind of to carry differential mode driving source The predictor method to wire crosstalk voltage in loop for the ac circuit.

Background technology

Calculating the electromagnetic interference that causes of transmission line in field of electromagnetic compatibility typically has two kinds of predictor methods, numerical method and many Conductor propagation line method.Differential mode driving source ac circuit crosstalk based on both approaches and radiation pre-estimation problem have research, Tsing-Hua University Zhu Danyang, the strict numerical method of Adiantum monochlamys has been derived and has been had the strict solution of limit for length's two-wire differential-mode current and radiation, But its result is also simply given in the form of electric field, is not directly calculated crosstalk voltage value.External Clayton Paul proposes three conductor transmission line model methods, establishes three conductor propagation line models of common mode driving source, and this model becomes Estimate the classical way of measurement transmission line crosstalk.Based on the transmission line model of Paul, some domestic scholars have also been made and grind Study carefully, including the Yang Jinhou of Xi'an precision optical machinery institute, Jiang Renbo of North China Electric Power University et al., the former establishes transmission Measurement model is estimated in the interference of line high-frequency coupling, and it is pre- that the latter establishes three conductor transmission line coupled interference for different types of conductor Estimate measurement model, but their researchs what is common is that prediction model is all that situation based on common mode driving source is set up, and And wire harness broadly falls into same system, that is, the crosstalk between the transmission line with common mode excitation can only be estimated, in the present invention The pre-estimation problem with differential mode driving source two-wire circuit wire to earth lead interference voltage in loop solving, and wire harness belongs to not The situation of homologous ray, does not also have existing prediction model or engineering survey method to solve.

In sum, existing reported literature is electric to earth lead interference in loop to differential mode driving source two-wire circuit wire The pre-estimation problem of pressure is not also studied, and the present invention, according to the coupling mechanism of crosstalk, establishes differential mode driving source parallel wire loop The new three conductor transmission line prediction models that wire solves to earth lead interference voltage engineering in loop, are this kind of wire harness arrangement In the case of line-to-line crosstalk size estimate the method for providing.

Content of the invention

It is an object of the invention to provide differential mode driving source parallel wire loop is in loop in a kind of solution electromagnetic compatibility The ac circuit with differential mode driving source of the pre-estimation problem of earth lead interference voltage is estimated to wire crosstalk voltage in loop Method.

The object of the present invention is achieved like this：

(1) first according to the position arrangement relation between wire, measure traverse line spacing d between any two_i(i=1,2), with And the height h on each conductor spacing ground_i(i=1,2,3), wire 1,2 is to apply to disturb differential mode return line, and wire 3 is perturbed line；

(2) according to the distance between each wire recording in step (1) relation and terrain clearance, obtained according to image method Unit length self-capacitance c between each wire_iAnd self-inductance l (i=1,2,3)_i(i=1,2,3), unit length mutual capacitance c_ij (i=1,2,3, j=1,2,3) and unit length mutual inductance lm_ij(i=1,2,3, j=1,2,3)；

(3) according to the inductance obtaining in step (2), capacitance, set up the ac circuit with differential mode driving source in loop Wire crosstalk voltage prediction model, wherein differential mode encourage the disturbed wire loop in resource loop and loop to be each connected to from electricity Sense l_iAll it is connected with self-capacitance c between (i=1,2,3), and each bar wire and ground_i(i=1,2,3), simultaneously in model between each wire All it is connected to mutual capacitance c_ij(i=1,2,3, j=1,2,3), mutual inductance lm_ij(i=1,2,3, j=1,2,3), each wire has Each top voltage V_i(z, t), top electric current I_i(z,t)；Terminal voltage V_i(z+ Δ z, t), terminal current I_i(z+ Δ z, t), its Middle i=1,2,3, (z, t) represents in the voltage x current value at z, during time t；

(4) three conductor transmission line equations are obtained by Kirchhoff's law：

Wherein I₁(z,t)、I₂(z, t)、I₃(z, t) represents on wire 1, wire 2, wire 3 respectively at z, electric current during time t, V₁(z,t)、V₂(z,t)、 V₃(z, t) represents on wire 1, wire 2, wire 3 respectively in the voltage at z, during time t；

(5) measure the magnitude of voltage V at differential mode loop two ends₁(z,t)、V₂(z, t), current value I₁(z,t)、I₂(z, t) bring into In three conductor transmission line equations, obtain the crosstalk voltage V on disturbed wire 3₃(z, t), crossfire I₃(z, t) size,

Extract capacitance per unit length：

Unit length inductance：

This invention solves the wire harness loop with differential mode driving source and estimates measurement to the crosstalk voltage size of wire in loop Problem, cross-interference issue also nobody during arrangement such for wire harness proposes corresponding crosstalk voltage and estimates measuring method, we Method can be simple, rapidly realize wire harness between system such arrangement when line-to-line crosstalk estimate measurement, save resources, and applicable surface Extensively, it is that the solution of problems provides a precedent.Provide reason for cluster binding bundle and arrangement problemss in field of electromagnetic compatibility By foundation, the solution to problems has stronger directive significance.

Brief description

Fig. 1 differential mode driving source parallel wire loop is to earth lead interference model in loop；

Parasitic parameter model in Fig. 2 image method measurement equation for transmission line；

Fig. 3 disturbed lead distal end crosstalk voltage result；

Fig. 4 disturbed lead proximal end crosstalk voltage result.

Specific embodiment

Below in conjunction with the accompanying drawings the present invention is described further.

For this problem, because disturbed wire is located between differential mode excitation resource loop, differential mode encourages two of resource loop Parallel wire is superimposed to the interference of disturbed wire, causes to disturb for disturbed wire and can not ignore, its loop model such as Fig. 1 Shown.Crosstalk voltage to be estimated, is necessary for setting up corresponding model, therefore the present invention, according to coupling mechanism, is extracted transmission line list Bit length stray inductance, parasitic capacitance matrix, and it is deduced the three conductor transmission line differential equations solving crosstalk voltage, set up Solve three conductor propagation line models of this problem, be the solution of problems provides Theoretical Prediction foundation, be aided with corresponding Measuring method, when just can achieve this kind of novel wire harness arrangement, crosstalk voltage estimates.

First according to crosstalk couplings mechanism, set up transmission line coupling cross-talk models, every wire all can include oneself of itself Mutual capacitance between electric capacity, self-inductance and wire, mutual inductance, ignore conductor wire losses, set up and are passed based on three conductors of this problem Defeated line coupling crosstalk anticipator circuit model.Next setting up three problem transmission line coupling crosstalks based on Kirchhoff's law estimates number Learn model：

Wherein I₁(z,t)、I₂(z,t)、I₃(z, t) is respectively the electric current on wire 1,2,3, V₁(z,t)、V₂(z,t)、V₃ (z, t) is respectively the voltage on wire 1,2,3.

Next measure the distance between each transmission line d, and the height h on each conductor spacing ground, as known conditions, The method being then based on mirror image sets up such new three conductor transmission line stray inductances, parasitic capacitance estimates measurement model, estimates Unit length inductance, capacitance size, its principle is as shown in Figure 2.

Extract unit length inductance and electric capacity between a wire as follows：

Capacitance per unit length：

Unit length inductance：

Wherein c_i(i=1,2,3) represents wire i unit length self-capacitance, c_ij(i=1,2,3, j=1,2,3) represents wire Unit length mutual capacitance between i, j；l_i(i=1,2,3) represents wire i unit length self-inductance, lm_ij(i=1,2,3, j=1,2, 3) represent unit length mutual inductance between wire i, j.

So far, based on differential mode driving source parallel wire loop to the pre-estimation problem of earth lead interference voltage in loop three Conductor transmission line prediction model is just set up, and just can directly obtain the near of disturbed wire by solving equation for transmission line End, the discreet value of far-end cross talk voltage.Result is as shown in Figure 3, Figure 4.

The present invention first has to obtain earth lead relative position relation in differential mode driving source parallel wire loop and loop, I.e. measure traverse line spacing d between any two, and terrain clearance h, and record wire two ends differential mode common mode load size and swash Encourage source amplitude and frequency, these are as the condition solving line-to-line crosstalk voltage.

Next according to the known conditions obtaining, recorded the unit length inductance between wire by image method.Asked based on this The schematic diagram of the image method of topic is as shown in Figure 2.Then obtain estimating biography based on Kirchhoff's law according to the arrangement relation of wire The new multi-conductor transmission lines equation of defeated line crosstalk voltage.And by the unit length inductance value obtaining according to unit in uniform dielectric Length inductance matrix, the relation of capacitance matrix

CL=μ ε E (9)

It is assured that capacitance per unit length Matrix C, wherein E is three rank unit matrixs, μ is dielectric permeability, ε is medium Dielectric constant.Mutual capacitance between the corresponding respective wire of each value in capacitance matrix or the self-capacitance value of wire itself.

After inductance capacitance value between prediction model and wire determines, the big small frequency of measurement driving source, measurement Result brings the crosstalk voltage that can be obtained by disturbed wire between differential mode loop in model into.This give the crosstalk electricity of emulation Pressure value, Fig. 3 is disturbed lead distal end crosstalk voltage, and Fig. 4 is disturbed lead proximal end crosstalk voltage, it can be seen that with The increase of frequency, the size of crosstalk voltage is gradually increased, and meets practical situation and the theory analysis of crosstalk couplings, each frequency institute Corresponding crossfire value is also shown in figure, has reached the purpose estimated, as can be seen from Figure, when frequency reaches 100MHz When, in differential mode loop, the crosstalk voltage of perturbed line can reach 6 × 10^-7V.

Claims (1)

1. a kind of ac circuit with differential mode driving source to the predictor method of wire crosstalk voltage in loop it is characterised in that：

(1) first according to the position arrangement relation between wire, measure traverse line spacing d between any two_i(i=1,2), and respectively The height h on conductor spacing ground_i(i=1,2,3), wire 1,2 is to apply to disturb differential mode return line, and wire 3 is perturbed line；

(2) according to the distance between each wire recording in step (1) relation and terrain clearance, each is obtained according to image method Unit length self-capacitance c between wire_iAnd self-inductance l (i=1,2,3)_i(i=1,2,3), unit length mutual capacitance c_ij(i= 1,2,3, j=1,2,3) and unit length mutual inductance lm_ij(i=1,2,3, j=1,2,3)；

(3) according to the inductance obtaining in step (2), capacitance, set up the ac circuit with differential mode driving source to wire in loop Crosstalk voltage prediction model, wherein differential mode encourage the disturbed wire loop in resource loop and loop to be each connected to self-inductance l_i All it is connected with self-capacitance c between (i=1,2,3), and each bar wire and ground_i(i=1,2,3), simultaneously in model between each wire all It is connected to mutual capacitance c_ij(i=1,2,3, j=1,2,3), mutual inductance lm_ij(i=1,2,3, j=1,2,3), each wire has respectively Ad initio terminal voltage V_i(z, t), top electric current I_i(z,t)；Terminal voltage V_i(z+ Δ z, t), terminal current I_i(z+ Δ z, t), wherein I=1,2,3, (z, t) represents in the voltage x current value at z, during time t；

(4) three conductor transmission line equations are obtained by Kirchhoff's law：

$\frac{\∂V_1(z,t)}{\∂z}=-l_1\frac{\∂I_1(z,t)}{\∂t}-{\mathrm{lm}}_{12}\frac{\∂I_2(z,t)}{\∂t}-{\mathrm{lm}}_{13}\frac{\∂I_3(z,t)}{\∂t}$

$\frac{\∂V_2(z,t)}{\∂z}=-{\mathrm{lm}}_{12}\frac{\∂I_1(z,t)}{\∂t}-l_2\frac{\∂I_2(z,t)}{\∂t}-{\mathrm{lm}}_{23}\frac{\∂I_3(z,t)}{\∂t}$

$\frac{\∂V_3(z,t)}{\∂z}=-{\mathrm{lm}}_{13}\frac{\∂I_1(z,t)}{\∂t}-{\mathrm{lm}}_{23}\frac{\∂I_2(z,t)}{\∂t}-l_3\frac{\∂I_3(z,t)}{\∂t}$

$\frac{\∂I_1(z,t)}{\∂z}=-(c_1+c_{12}+c_{13})\frac{\∂V_1(z,t)}{\∂t}+c_{12}\frac{\∂V_2(z,t)}{\∂t}+c_{13}\frac{\∂V_3(z,t)}{\∂t}$

$\frac{\∂I_2(z,t)}{\∂z}=c_{12}\frac{\∂V_1(z,t)}{\∂t}-(c_2+c_{12}+c_{23})\frac{\∂V_2(z,t)}{\∂t}+c_{23}\frac{\∂V_3(z,t)}{\∂t}$

$\frac{\∂I_3(z,t)}{\∂z}=c_{13}\frac{\∂V_1(z,t)}{\∂t}+c_{23}\frac{\∂V_2(z,t)}{\∂t}-(c_3+c_{13}+c_{23})\frac{\∂V_3(z,t)}{\∂t}$

Wherein I₁(z,t)、I₂(z,t)、I₃(z, t) represents on wire 1, wire 2, wire 3 respectively at z, during time t Electric current, V₁(z,t)、V₂(z,t)、V₃(z, t) represents on wire 1, wire 2, wire 3 respectively in the electricity at z, during time t Pressure；

(5) measure the magnitude of voltage V at differential mode loop two ends₁(z,t)、V₂(z, t), current value I₁(z,t)、I₂(z, t) bring three into and lead In body equation for transmission line, obtain the crosstalk voltage V on disturbed wire 3₃(z, t), crossfire I₃(z, t) size,

Extract capacitance per unit length：

$C=\left[\begin{array}{ccc}{c}_1+c_{12}+c_{13}& -c_{12}& -c_{13}\\ -c_{12}& c_2+c_{12}+c_{23}& -c_{23}\\ -c_{13}& -c_{23}& c_3+c_{13}+c_{23}\end{array}\right],$

Unit length inductance：

$L=\left[\begin{array}{ccc}{l}_1& {\mathrm{lm}}_{12}& {\mathrm{lm}}_{13}\\ {\mathrm{lm}}_{12}& l_2& {\mathrm{lm}}_{23}\\ {\mathrm{lm}}_{13}& {\mathrm{lm}}_{23}& l_3\end{array}\right].$