CN104020336A - 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

The predictor method of a kind of ac circuit with differential mode driving source to wire crosstalk voltage in loop

Technical field

The invention belongs in electromagnetic compatibility the transmission line wire harness field of crosstalking, what be specifically related to is the predictor method of a kind of ac circuit with differential mode driving source to wire crosstalk voltage in loop.

Background technology

The electromagnetic interference (EMI) causing at electromagnetic compatibility field calculating transmission line generally has two kinds of predictor methods, numerical method and many conductor transmission line method.Differential mode driving source ac circuit based on these two kinds of methods is crosstalked and radiation is estimated problem and had research, Zhu of Tsing-Hua University Danyang, Adiantum monochlamys has been derived and has been had the strict solution of the differential-mode current of limit for length's two-wire and radiation by strict numerical method, but its result also just provides with the form of electric field, does not directly calculate crosstalk voltage value.External Clayton Paul has proposed three conductor transmission line model methods, has set up three conductor transmission line models of common mode driving source, and this model becomes to estimate measures the classical way that transmission line is crosstalked.Transmission line model based on Paul, some domestic scholars have also done a little research, Yang Jinhou comprising Xi'an precision optical machinery research institute, the people such as the Jiang Renbo of North China Electric Power University, the former has set up the interference of transmission line high-frequency coupling and has estimated measurement model, the latter has set up three conductor transmission line coupled interference for dissimilar conductor and has estimated measurement model, but the common ground of their research is exactly prediction model, be all that situation based on common mode driving source is set up, and wire harness all belongs to same system, namely can only estimate with crosstalking between the transmission line of common mode excitation, for the problem of estimating to earth lead interference voltage in loop with differential mode driving source two-wire circuit wire solving in the present invention, and wire harness belongs to the situation of different system, also do not have existing prediction model or engineering survey method to solve.

In sum, existing reported literature is not also studied the problem of estimating of earth lead interference voltage in loop differential mode driving source two-wire circuit wire, the present invention is according to the coupling mechanism of crosstalking, having set up differential mode driving source parallel wire return wire to the novel three conductor transmission line prediction models that in loop, earth lead interference voltage engineering solves, is the arrange method that provides of estimating of line-to-line crosstalk size in situation of this kind of wire harness.

Summary of the invention

The object of the present invention is to provide a kind of solve in electromagnetic compatibility differential mode driving source parallel wire loop to the ac circuit with differential mode driving source of the problem of estimating of earth lead interference voltage in loop the predictor method to wire crosstalk voltage in loop.

The object of the present invention is achieved like this:

(1) first according to the relation of arranging of the position between wire, measure traverse line spacing d between any two _i(i=1,2), and the height h on each conductor spacing ground _i(i=1,2,3), wire 1,2 is disturbed differential mode return line for executing, and wire 3 is perturbed line;

(2), according to distance relation and terrain clearance between each wire recording in step (1), according to image method, obtain the unit length self-capacitance c between each wire _i(i=1,2,3) and self-inductance l _i(i=1,2,3), unit length mutual capacitance c _ij(ij=1,2,3) and unit length mutual inductance lmij (ij=1,2,3);

(3) according to the inductance, the capacitance that obtain in step (2), set up ac circuit with differential mode driving source to wire crosstalk voltage prediction model in loop, wherein the disturbed wire loop in differential mode driving source loop and loop is all connected to self-inductance l separately _i(i=1,2,3), and between each wire and ground, be all connected with self-capacitance c _i(i=1,2,3) are all connected to mutual capacitance c between each wire in model simultaneously _ij(ij=1,2,3), mutual inductance lmij (ij=1,2,3), every wire has top voltage V separately _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), i=1 wherein, 2,3, (z, t) is illustrated in distance z place, electric current and voltage value during time t;

(4) by Kirchhoff's law, obtain three conductor transmission line equations:

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

$\frac{\∂V_2(z,t)}{\∂z}=-l_{m12}\frac{\∂I_1(z,t)}{\∂t}-l_2\frac{\∂I_2(z,t)}{\∂t}-{\mathrm{lm}}_{23}\frac{\∂I_3(z,t)}{\∂t}$

$\frac{\∂V_3(z,t)}{\∂z}=-l_{m13}\frac{\∂I_1(z,t)}{\∂t}-{\mathrm{lm}}_{23}\frac{\∂I_2(z,t)}{\∂t}-l_3\frac{\∂I_3(z,t)}{\∂t}$

$\frac{\∂I_1(z,t)}{\∂z}=-(c_1+c_2+c_{13})\frac{\∂V_1(z,t)}{\∂t}+c_{12}\frac{\∂V_2(z,t)}{\∂t}+c_{13}\frac{\∂V_3(z,t)}{\∂t}$

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

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

I wherein ₁(z, t), I ₂(z, t), I ₃(z, t) represents respectively on wire 1, wire 2, wire 3 at distance z place, electric current during time t, V ₁(z, t), V ₂(z, t), V ₃(z, t) represents respectively on wire 1, wire 2, wire 3 at distance z place, voltage during time t;

(5) measure the magnitude of voltage V at two ends, differential mode loop ₁(z, t), V ₂(z, t), current value I ₁(z, t), I ₂(z, t) also brings in three conductor transmission line equations, obtains the crosstalk voltage V on disturbed wire 3 ₃(z, t), crossfire I ₃(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:

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

This invention has solved with the wire harness loop of differential mode driving source the crosstalk voltage size of wire in loop has been estimated to measurement problem, cross-interference issue when this type of is arranged for wire harness also nobody proposes corresponding crosstalk voltage and estimates measuring method, this method can be simple, realize rapidly wire harness between system this type of while arranging line-to-line crosstalk estimate measurement, saving resource, and widely applicable, for the solution of problems provides a precedent.For wire harness in electromagnetic compatibility field lashes and arrangement problems provides theoretical foundation, the solution of problems is had to stronger directive significance.

Accompanying drawing explanation

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

Fig. 2 image method is measured parasitic parameter model in equation for transmission line;

The disturbed lead distal end crosstalk voltage of Fig. 3 result;

The disturbed lead proximal end crosstalk voltage of Fig. 4 result.

Embodiment

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

For this problem, because disturbed wire is between differential mode driving source loop, two parallel wires in differential mode driving source loop are superimposed to the interference of disturbed wire, cause concerning disturbed wire and disturb and can not ignore, and its loop model as shown in Figure 1.Estimate crosstalk voltage, just must set up corresponding model, therefore the present invention is according to coupling mechanism, transmission line unit length stray inductance, stray capacitance matrix have been extracted, and derived the three conductor transmission line differential equations that solve crosstalk voltage, set up three conductor transmission line models of head it off, for the solution of problems provides Theoretical Prediction foundation, be aided with corresponding measuring method, in the time of just can realizing this kind of Novel wire harness layout, crosstalk voltage estimates.

First according to crosstalk couplings mechanism, set up transmission line coupling crosstalk model, every wire all can comprise mutual capacitance, the mutual inductance between self self-capacitance, self-inductance and wire, ignores wire loss, sets up the three conductor transmission line coupling crosstalk anticipator circuit models based on this problem.Next based on Kirchhoff's law, set up three problem transmission line coupling crosstalks and estimate mathematical model:

$\frac{\∂V_1(z,t)}{\∂z}=-l_1\frac{\∂I_1(z,t)}{\∂t}-{\mathrm{lm}}_{12}\frac{\∂I_2(z,t)}{\∂t}-{\mathrm{lm}}_{13}\frac{\∂I_3(z,t)}{\∂t}---\left(1\right)$

$\frac{\∂V_2(z,t)}{\∂z}=-l_{m12}\frac{\∂I_1(z,t)}{\∂t}-l_2\frac{\∂I_2(z,t)}{\∂t}-{\mathrm{lm}}_{23}\frac{\∂I_3(z,t)}{\∂t}---\left(2\right)$

$\frac{\∂V_3(z,t)}{\∂z}=-l_{m13}\frac{\∂I_1(z,t)}{\∂t}-{\mathrm{lm}}_{23}\frac{\∂I_2(z,t)}{\∂t}-l_3\frac{\∂I_3(z,t)}{\∂t}---\left(3\right)$

$\frac{\∂I_1(z,t)}{\∂z}=-(c_1+c_2+c_{13})\frac{\∂V_1(z,t)}{\∂t}+c_{12}\frac{\∂V_2(z,t)}{\∂t}+c_{13}\frac{\∂V_3(z,t)}{\∂t}---\left(4\right)$

$\frac{\∂I_2(z,t)}{\∂z}=c_{12}\frac{\∂V_1(z,t)}{\∂t}-(c_2+c_{12}+c_{23})\frac{\∂V_2(z,t)}{\∂t}+c_{23}\frac{\∂V_3(z,t)}{\∂t}---\left(5\right)$

$\frac{\∂I_3(z,t)}{\∂z}=c_{13}\frac{\∂V_1(z,t)}{\∂t}+c_{23}\frac{\∂V_2(z,t)}{\∂t}-(c_3+c_{13}+c_{23})\frac{\∂V_3(z,t)}{\∂t}---\left(6\right)$

I wherein ₁(z, t), I ₂(z, t), I ₃(z, t) is respectively the electric current on wire 1,2,3, V ₁(z, t), V ₂(z, t), V ₃(z, t) is respectively the voltage on wire 1,2,3.

Next measure the distance d between each transmission line, and the height h on each conductor spacing ground, as known conditions, then the method based on mirror image is set up these type of novel three conductor transmission line stray inductances, stray capacitance is estimated measurement model, estimate unit length inductance, capacitance size, its principle as shown in Figure 2.

Between an extraction wire, unit length inductance and electric capacity are as follows:

Capacitance per unit length:

$C=\left[\begin{array}{ccc}{c}_1+c_{12}+c_{13}& -c_{12}& -c_{13}\\ -c_{12}& c_2+c_{12}+c_{23}& -c_{23}\\ -c_{13}& -c_{23}& c_3+c_{13}+c_{23}\end{array}\right]---\left(7\right)$

Unit length inductance:

$L=\left[\begin{array}{ccc}{l}_1& {\mathrm{lm}}_{12}& {\mathrm{lm}}_{13}\\ {\mathrm{lm}}_{12}& l_2& {\mathrm{lm}}_{23}\\ {\mathrm{lm}}_{13}& {\mathrm{lm}}_{23}& l_3\end{array}\right]---\left(8\right)$

C wherein _i(i=1,2,3) represent wire i unit length self-capacitance, c _ij(ij=1,2,3) represent unit length mutual capacitance between wire i, j; l _i(i=1,2,3) represent wire i unit length self-inductance, and lmij (ij=1,2,3) represents unit length mutual inductance between wire i, j.

So far, based on differential mode driving source parallel wire loop, three conductor transmission line prediction models of the problem of estimating of earth lead interference voltage in loop have just been set up, by solving equation for transmission line, just can directly have been obtained the near-end of disturbed wire, the discreet value of far-end cross talk voltage.Result as shown in Figure 3, Figure 4.

First the present invention will obtain earth lead relative position relation in differential mode driving source parallel wire loop and loop, be measure traverse line spacing d between any two, and terrain clearance h, and recording wire two ends differential mode common mode load and driving source amplitude and frequency, these are as the condition that solves line-to-line crosstalk voltage.

Next according to the known conditions obtaining, by image method, record the unit length inductance between wire.The schematic diagram of the image method based on this problem as shown in Figure 2.Then according to the relation of arranging of wire, based on Kirchhoff's law, obtain estimating novel many conductor transmission line equation of transmission line crosstalk voltage.And by the unit length inductance value obtaining according to unit length inductance matrix in uniform dielectric, the relation of capacitance matrix

CL＝μεE (9)

Just can determine capacitance per unit length Matrix C, wherein E is three rank unit matrixs, and μ is dielectric permeability, and ε is medium specific inductive capacity.Mutual capacitance between the corresponding respective wire of each value in capacitance matrix or the self-capacitance value of wire self.

After inductance capacitance value between prediction model and wire is determined, measure the large small frequency of driving source, measurement result is brought into the crosstalk voltage that just can obtain disturbed wire between differential mode loop in model.Here provided the crosstalk voltage value of emulation; Fig. 3 is disturbed lead distal end crosstalk voltage, and Fig. 4 is disturbed lead proximal end crosstalk voltage, as can be seen from the figure; increase along with frequency; the size of crosstalk voltage increases gradually, meets actual conditions and the theoretical analysis of crosstalk couplings, and the corresponding crossfire value of each frequency is also all presented in figure; reached the object of estimating; as can be seen from Figure, when frequency reaches 100MHz, in differential mode loop, the crosstalk voltage of perturbed line can reach 6e-7V.

Claims (1)

1. the predictor method to wire crosstalk voltage in loop with the ac circuit of differential mode driving source, is characterized in that:

(1) first according to the relation of arranging of the position between wire, measure traverse line spacing d between any two _i(i=1,2), and the height h on each conductor spacing ground _i(i=1,2,3), wire 1,2 is disturbed differential mode return line for executing, and wire 3 is perturbed line;

(2), according to distance relation and terrain clearance between each wire recording in step (1), according to image method, obtain the unit length self-capacitance c between each wire _i(i=1,2,3) and self-inductance l _i(i=1,2,3), unit length mutual capacitance c _ij(ij=1,2,3) and unit length mutual inductance lmij (ij=1,2,3);

(3) according to the inductance, the capacitance that obtain in step (2), set up ac circuit with differential mode driving source to wire crosstalk voltage prediction model in loop, wherein the disturbed wire loop in differential mode driving source loop and loop is all connected to self-inductance l separately _i(i=1,2,3), and between each wire and ground, be all connected with self-capacitance c _i(i=1,2,3) are all connected to mutual capacitance c between each wire in model simultaneously _ij(ij=1,2,3), mutual inductance lmij (ij=1,2,3), every wire has top voltage V separately _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), i=1 wherein, 2,3, (z, t) is illustrated in distance z place, electric current and voltage value during time t;

(4) by Kirchhoff's law, obtain three conductor transmission line equations:

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

$\frac{\∂V_2(z,t)}{\∂z}=-l_{m12}\frac{\∂I_1(z,t)}{\∂t}-l_2\frac{\∂I_2(z,t)}{\∂t}-{\mathrm{lm}}_{23}\frac{\∂I_3(z,t)}{\∂t}$

$\frac{\∂V_3(z,t)}{\∂z}=-l_{m13}\frac{\∂I_1(z,t)}{\∂t}-{\mathrm{lm}}_{23}\frac{\∂I_2(z,t)}{\∂t}-l_3\frac{\∂I_3(z,t)}{\∂t}$

$\frac{\∂I_1(z,t)}{\∂z}=-(c_1+c_2+c_{13})\frac{\∂V_1(z,t)}{\∂t}+c_{12}\frac{\∂V_2(z,t)}{\∂t}+c_{13}\frac{\∂V_3(z,t)}{\∂t}$

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

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

I wherein ₁(z, t), I ₂(z, t), I ₃(z, t) represents respectively on wire 1, wire 2, wire 3 at distance z place, electric current during time t, V ₁(z, t), V ₂(z, t), V ₃(z, t) represents respectively on wire 1, wire 2, wire 3 at distance z place, voltage during time t;

(5) measure the magnitude of voltage V at two ends, differential mode loop ₁(z, t), V ₂(z, t), current value I ₁(z, t), I ₂(z, t) also brings in three conductor transmission line equations, obtains the crosstalk voltage V on disturbed wire 3 ₃(z, t), crossfire I ₃(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

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