JP2006115402A - Adaptive common mode noise eliminating device for communication line - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adaptive common mode noise eliminating device for a communication line for eliminating common mode noises in a wide frequency range on a communication line. <P>SOLUTION: The adaptive common mode noise eliminating device 1 for a communication line is provided with an induced voltage detector 11, for detecting the common mode noise of a communication line 2 in the manner of the induced voltage of the communication line 2; a signal detector 12 for detecting at least any one of a normal mode voltage, a normal mode current, a common mode voltage, and a common mode current of the communication line 2; a noise eliminating signal generator 13 for generating a noise eliminating signal for eliminating the common mode noise; a noise eliminating signal applier 14 for applying the generated noise eliminating signal to the communication line 2; and an optimization processor 15 for using the detected common mode noise as a reference signal, and deciding the amplitude value and the phase information of the noise eliminating signal so that the amplitude value of this common mode noise may be reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a communication line adaptive type common mode noise removing apparatus for removing common mode noise in a wide frequency range on a communication line.

  In recent years, electromagnetic interference caused by unnecessary radio waves (electromagnetic noise) generated from wireless devices and inverter devices has become a problem. When unwanted radio waves are induced on communication lines, electromagnetic interference may occur in communication devices and communication quality may be degraded. CISPR Pub.22). Moreover, in addition to a reduction in the strength of electronic devices accompanying an increase in speed and power consumption of electronic devices, for example, new communication forms such as power line carrier communication (Non-Patent Document 1) using a power line as a communication line are becoming widespread. For this reason, the problem of electromagnetic induction on communication lines is becoming increasingly complex.

As a means for improving electromagnetic induction in a communication line, a method using an adaptive common mode noise removing device for communication line (Patent Document 1, etc.), a power supply circuit and a communication circuit of a communication device when a lightning surge enters, There are proposed a method for suppressing the occurrence of a potential difference between them (Patent Document 2, etc.), a method for detecting an output signal of a communication circuit and improving the S / N ratio (Patent Document 3, etc.), and the like. These are effective when an unnecessary radio wave / electromagnetic interference wave source that causes electromagnetic induction is clear, or when an induction signal in a specific frequency band is deleted.
Japanese Utility Model Publication No. Hei 6-29226 Japanese Patent Laid-Open No. 11-225433 Japanese Patent No. 323164 Akiyama, et al., “Examination of Pseudo-Communication Circuits for Equipment Testing in Power Line Carrier Communications (PLC)”, IEICE Techniques EMCJ2003-12, pp.71-75, 2003-4

  The above-described conventional means for improving electromagnetic induction to a communication line is effective when an unnecessary radio wave / electromagnetic interference wave source that causes electromagnetic induction is clear or when an induction signal in a specific frequency band is deleted.

  However, (1) it is necessary to optimize the filter according to the noise type (for example, a conventional LC noise filter has a resonance frequency peculiar to a circuit element (a), so that a desired attenuation amount is set to a wide frequency range. (B) In the case of a noise filter that cuts a particularly low frequency band, there is a restriction such as an increase in the size of the inductance element), (2) Response to a case where noise frequency fluctuation occurs There is a problem in that it is not easy, and (3) it is not easy to cope with an event in which the frequency band of unnecessary radio waves and electromagnetic interference waves that cause electromagnetic induction cannot be specified in advance.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a communication line adaptive common mode noise removing device for removing common mode noise in a wide frequency range on the communication line. There is to do.

  In order to solve the above-mentioned problem, the present invention of claim 1 is provided between a communication device or a communication line termination unit using a balanced line or a power line that is a balanced line as a communication line, and the communication line. A common mode noise detecting unit for detecting common mode noise of the communication line by at least one of an induced voltage, an induced current of the line, and a radiated electromagnetic field in the vicinity of the communication line; and a normal mode voltage and a normal mode current of the communication line A signal detection unit for detecting at least one of a common mode voltage and a common mode current, a noise removal signal generation unit for generating a noise removal signal for removing the common mode noise, and the generated noise removal signal A noise removal signal applying unit that applies to the communication line in at least one of a common mode voltage and a common mode current; and the detection Means for Solving with an Adaptive Common Mode Noise Rejecting Device for Communication Line, characterized in that it comprises an optimization processing unit for determining the amplitude value and phase information of the noise removal signal so that the amplitude value of the mon mode noise becomes small And

  According to the second aspect of the present invention, the optimization processing unit repeats the optimization process a predetermined number of times to determine a filter coefficient for defining the noise removal signal, and an arbitrarily specified optimum 2. The communication line adaptive type common mode noise removing apparatus according to claim 1, wherein at least one of determining the filter coefficient is repeated by repeating the optimization process until a convergence level of the optimization function is reached. To do.

  According to a third aspect of the present invention, there is provided the communication line adaptive common mode noise removing apparatus according to the first or second aspect, wherein the detection value at the signal detection unit is minimized.

  According to a fourth aspect of the present invention, the noise removal signal applying unit includes a transformer for connecting a winding of a transformer inserted in the communication line and the noise removal signal generation unit. The communication line adaptive common mode noise elimination device according to any one of 3 is used as a solution.

  The present invention according to claim 5 is characterized in that the noise removal signal applying unit includes a transformer including an inductance inserted in each line of the communication line and an inductance connected to the noise removal signal generation unit. The communication line adaptive common mode noise elimination device according to any one of claims 1 to 3 is used as a solution.

  According to the adaptive common mode noise elimination device for communication lines of the present invention, the optimization processing unit determines the amplitude value and phase information of the noise elimination signal so that the amplitude value of the detected common mode noise becomes small. Therefore, common mode noise in a wide frequency range on the communication line can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram of an adaptive common mode noise removing device for communication lines according to the present embodiment.

  In FIG. 1, 1 is an adaptive common mode noise elimination device for communication lines, 2 is a communication line that is a balanced line (or a power line when a power line that is a balanced line is a communication line), and 3 is a communication line termination unit (or (Communication equipment) 4 is a noise source.

  The communication line adaptive common mode noise removing device 1 includes an induction voltage detection unit 11 (common mode noise detection unit) that detects common mode noise of the communication line 2 in the form of an induction voltage of the communication line 2, and a communication line 2. A signal detection unit 12 that detects at least one of a normal mode voltage, a normal mode current, a common mode voltage, and a common mode current; a noise removal signal generation unit 13 that generates a noise removal signal for removing common mode noise; The noise removal signal applying unit 14 that applies the generated noise removal signal to the communication line 2 and the detected common mode noise as a reference signal, and the amplitude of the noise removal signal so that the amplitude value of the common mode noise is reduced. And an optimization processing unit 15 that determines the value and the phase information.

  FIG. 1 shows that when noise generated from a noise source 4 such as an electronic filter is induced as common mode noise to a communication line 2 via a transmission line such as a space or a power line, the communication line 2 and the communication line termination are shown. This corresponds to the image of removing the noise signal of the communication line 2 using the communication line adaptive common mode noise removing device 1 installed between the units 3.

Here, the common mode noise of the communication line 2 is detected by the induced voltage detector 11 as a common mode induced voltage. That is, the induced voltage detection unit 11 detects a noise signal that propagates through 2 ⁿ communication lines 2 in the same phase. Here, as means for realizing the induced voltage detection unit 11, a capacitive voltage probe, a pseudo communication network (Japanese Patent Laid-Open Nos. 3-222529, 3-289221, and 4-20126 are disclosed). Or a circuit based on or equivalent to CISPR Pub.16-1-1933), a method of combining this pseudo communication network and a filter for selecting an arbitrary frequency band component.

  The signal detection unit 12 has at least one of a function of detecting a communication signal affected by a noise signal flowing inside the communication line 2 in a normal mode and a function of detecting a common mode signal of the communication line 2, and detects the detected signal. The value is transferred to the optimization processing unit 15. Here, as means for realizing the signal detection unit 12, in the case of the common mode, in the case of the pseudo communication network (for voltage), the capacitive voltage probe (for voltage), the current probe (for current), and the normal mode A differential voltage probe (for voltage), a high impedance probe (for voltage), a current probe (for current), etc. can be used. Further, in FIG. 1, when the common mode voltage is targeted, the induced voltage detection unit 11 can be used as a signal detection unit. Further, in the case of normal mode voltage, the normal mode voltage of one set of communication lines 2 is selected as an observation target from a plurality of sets of communication lines 2, while in the case of normal mode current, the normal mode components are observed from communication line 2 Select the measurement line so that you can.

  The optimization processing unit 15 uses the induced voltage detected by the induced voltage detection unit 11 as a reference signal, and minimizes the detection value at the signal detection unit 12 (that is, indirectly between the induced voltage and the noise removal signal). Set the filter coefficients that determine the characteristics of the denoising signal (to minimize the total value). In addition, as an algorithm for determining the filter coefficient of the adaptive common mode noise removal apparatus 1 for communication lines, a minimum mean square algorithm, an adaptive lattice algorithm, a sequential least square algorithm, a least square lattice type algorithm, a fast transversal filter ( FTF algorithm etc.) and others can be used. Detailed information is published in Yoji Iiguni, “Adaptive Signal Processing Algorithm”, Baifukan, 2000.

  Further, the optimization processing unit 15 can determine the filter coefficient by repeating the optimization processing a number of times designated in advance. Also, the filter coefficient can be determined by repeating the optimization process until the convergence level of the arbitrarily specified optimization function is reached. Further, the filter coefficient may be determined by performing both of these methods.

  In addition, when the optimization processing unit 15 uses the induced voltage to the communication line 2 measured by the induced voltage detection unit 11 as a reference signal, the time variation of the induced voltage measured by the induced voltage detection unit 11 is used as it is. Either a method or a method of obtaining a frequency distribution in an arbitrary frequency band from time variation of the induced voltage measured by the induced voltage detection unit 11 and selecting and using a fluctuation component in the arbitrary frequency band can be considered.

  Next, the noise removal signal whose characteristics (specifically, amplitude value and phase information, etc.) are determined by the filter coefficient determined by the optimization processing unit 15 is supplied to the common mode voltage and common by the noise removal signal application unit 14. The mode current is applied to the communication line 2 in the signal format. As a means for realizing the noise removal signal applying unit 14, in the case of a common mode voltage, a capacitive voltage probe, a pseudo communication circuit network, an interference wave applying filter (JP-A-6-209300, JP-A-10-101177). In the case of a common mode current, a current probe, a transformer, etc. can be used.

  That is, the induced voltage detected by the induced voltage detection unit 11 is minimized by the series of processes described above, thereby suppressing the induced voltage (common mode noise) of the communication line 2 or to the outside via the communication line 2. It is possible to suppress the output of noise. In the example of FIG. 1, the communication line 2 is composed of two lines, but the present invention can also be applied to the case of four lines or the like. In the example of FIG. 1, the induced voltage detection unit 11 is provided in the communication line adaptive common mode noise removal device 1. However, depending on the target system, the communication line adaptive common mode noise removal is performed. It can be provided outside the apparatus 1 and is preferably installed at a position close to the noise source 4 in order to improve the accuracy of the filter coefficient determination by the optimization processing unit 15.

  FIG. 2 is another configuration diagram of the adaptive common mode noise elimination device for communication lines according to the present embodiment. In FIG. 2, 11 </ b> A is an induced current detection unit (common mode noise detection unit) that detects common mode noise of the communication line 2 in the form of the induced current of the communication line 2.

FIG. 2 corresponds to an example in which an induced current detector 11A is used instead of the induced voltage detector 11 in FIG. The induced current detection unit 11A detects a noise signal propagating through the ²ⁿ communication lines 2 in the same phase as a current common mode signal. The optimization processing unit 15 uses the induced current detected by the induced current detection unit 11A as a reference signal, and minimizes the detection value in the signal detection unit 12 (that is, the total value of the induced current and the noise removal signal is calculated). Set the filter coefficient of the adaptive common mode noise eliminator for communication lines (to minimize).

  Further, in the optimization processing unit 15, when referring to the induced current of the communication line 2 detected by the induced current detecting unit 11A, the frequency distribution is obtained from the method of using the induced current as it is and the time variation of the induced current, Any method of selecting and using a fluctuation component in an arbitrary frequency band can be employed. As means for realizing the induced current detector 11A, a method using a current probe for conducting wire measurement, a method using a magnetic sensor as a current sensor, a current probe for conducting wire measurement and an arbitrary frequency band component are selected. The method of combining these filters, the method of combining the said filter using a magnetic sensor as a current sensor, etc. can be considered. In FIG. 2, when the signal detection unit 12 detects a common mode current, the induced voltage detection unit 11 can be used as the signal detection unit 12.

  In addition, in the example of FIG. 2, the induction current detection unit 11A is provided in the communication line adaptive common mode noise removal device 1, but depending on the target system, the communication line adaptive common mode noise removal is performed. It can be provided outside the apparatus 1 and is preferably installed at a position close to the noise source 4 in order to improve the accuracy of the filter coefficient determination by the optimization processing unit 15.

  FIG. 3 is another configuration diagram of the adaptive common mode noise removal device for communication lines according to the present embodiment. In FIG. 3, 11B is a radiated electromagnetic field detector (common mode noise detector) that detects common mode noise of the communication line 2 in the form of a radiated electromagnetic field near the communication line 2.

  FIG. 3 corresponds to an example in which a radiated electromagnetic field detector 11B is used in place of the induced voltage detector 11 in FIG. The radiated electromagnetic field detector 11B detects a noise signal that is guided to the communication line 2 in the time domain. The optimization processing unit 15 uses the radiated electromagnetic field detected by the radiated electromagnetic field detection unit 11B as a reference signal, and minimizes the detection value at the signal detection unit 12 (that is, the sum of the induced current and the noise removal signal). Set the filter coefficient of the adaptive common mode noise elimination device for communication lines (to minimize the value).

  In the optimization processing unit 15, when referring to the radiated electromagnetic field detected by the radiated electromagnetic field detection unit 11B, a frequency distribution is obtained from a method of using the radiated electromagnetic field as it is and a time variation of the radiated electromagnetic field, Any method of selecting and using a fluctuation component in an arbitrary frequency band can be employed. As a means for realizing the radiated electromagnetic field detection unit 11B, a method using an antenna for measuring a radiated electromagnetic field, a method of combining the antenna and a filter for selecting an arbitrary frequency band component, and the like can be considered.

  In the example of FIG. 3, the radiated electromagnetic field detector 11B is provided outside the communication line adaptive common mode noise removing device 1, but depending on the target system, the communication line adaptive common mode noise is provided. It is also possible to provide in the removal apparatus 1.

  FIG. 4 is a diagram illustrating a circuit configuration example using a transformer as the noise removal signal applying unit 14 when the number of communication lines 2 is two. In FIG. 4, a, a ', b, b' indicate input / output terminals, and L indicates inductance.

  In FIG. 4A, a transformer T2 (connected to the noise removal signal generation unit 13 with respect to the midpoint of the winding of the transformer T1 (main circuit element = inductance L1) inserted between the communication lines 2 is used. Main circuit element = inductance L2) is installed. At this time, in the transformer T1, the method of adding the noise removal signal generated by the noise removal signal generation unit 13 so that the magnetic field between the two inductances L2 cancels each other. Noise signal can be suppressed.

  Further, in FIG. 4B, inductance is inserted into each line of the communication line 2, and inductance connected to the noise removal signal generation unit 13 is installed on the opposing side (a transformer is installed on each line). At this time, by adding a noise removal signal generated by the noise removal signal generation unit 13 so that the magnetic field between two inductances (between L1 or L2) cancels out in each transformer, The common mode noise signal can be suppressed.

  Although FIG. 4 shows the case of two communication lines, the same can be applied to other cases such as four lines and eight lines.

  FIG. 5 is a diagram showing an example of the result of confirming the effect of suppressing the common mode induced current noise by simulation in the configuration shown in FIG. In FIG. 5, the horizontal axis corresponds to time, the vertical axis corresponds to the induced current detected by the induced current detection unit 11 </ b> A, and (a) is an example in which induced noise is simply applied to the communication line 2, (b ) Is an example in the case of using the adaptive common mode noise removing device 1 for communication line in FIG. Here, an example is assumed in which a current probe that covers a frequency band from 10 Hz to 10 MHz is used as the induced current detection unit 11A.

  As shown in FIG. 5, it can be seen that the amplitude level of the induced current noise having different periods on the time axis is reduced to 1/20 or less. That is, when common mode noise having a wide frequency component is induced in the communication line 2, it can be confirmed from the result of FIG. 5 that the adaptive common mode noise removal device 1 for communication line is effective.

  In this embodiment, it is also possible to detect common mode noise of a communication line in two or more forms among induced current, induced voltage, and radiated electromagnetic field, and the noise removal signal is detected as common mode voltage and common mode. It is also possible to apply to the communication line in both forms of current.

  As is clear from the above description, according to the present invention, it is possible to efficiently realize suppression of induction of a noise signal to the communication line and suppression of output of the noise signal to the outside via the communication line. In addition, the communication line adaptive common mode noise removing device of the present invention is provided on one or more pairs of communication lines, between the communication line and the communication line termination unit (or communication device), on the power line, between the power line and the power line termination unit. , Etc., a great effect can be expected in the reduction and countermeasure of electromagnetic interference generated during communication use and electromagnetic interference through communication lines.

It is a block diagram of the adaptive common mode noise removal apparatus for communication lines which concerns on this Embodiment. It is another block diagram of the adaptive common mode noise removal apparatus for communication lines which concerns on this Embodiment. It is another block diagram of the adaptive common mode noise removal apparatus for communication lines which concerns on this Embodiment. FIG. 3 is a diagram illustrating a circuit configuration example using a transformer as the noise removal signal applying unit 14 when the number of communication lines 2 is two. It is a figure which shows the example of a result which confirmed the suppression effect of the induction current noise of a common mode by simulation with the structure shown in FIG.

Explanation of symbols

1 Communication Type Adaptive Common Mode Noise Eliminator 2 Communication Line 3 Communication Line Termination (or Communication Equipment)
4 Noise source 11 Induced voltage detector 11A Induced current detector 11B Radiated electromagnetic field detector 12 Signal detector 13 Noise removal signal generator 14 Noise removal signal application unit 15 Optimization processor

Claims (5)

Installed between the communication line that uses the balanced line or the power line that is the balanced line as a communication line or the communication line termination unit and the communication line,
A common mode noise detection unit that detects common mode noise of the communication line by at least one form of the induction voltage, the induction current, and the radiated electromagnetic field near the communication line;
A signal detector that detects at least one of a normal mode voltage, a normal mode current, a common mode voltage, and a common mode current of the communication line;
A noise removal signal generator for generating a noise removal signal for removing the common mode noise;
A noise removal signal applying unit that applies the generated noise removal signal to the communication line in the form of at least one of a common mode voltage and a common mode current;
An adaptive common mode noise removal for communication lines, comprising: an optimization processing unit that determines an amplitude value and phase information of the noise removal signal so that an amplitude value of the detected common mode noise is reduced. apparatus.   The optimization processing unit repeats the optimization process a predetermined number of times to determine a filter coefficient for defining the noise removal signal, and until a convergence level of an arbitrarily specified optimization function is reached 2. The adaptive common mode noise removal device for communication lines according to claim 1, wherein at least one of the optimization process is repeated to determine the filter coefficient.   3. The adaptive common mode noise removal device for communication lines according to claim 1, wherein a detection value at the signal detection unit is minimized.   The communication according to any one of claims 1 to 3, wherein the noise removal signal applying unit includes a transformer that connects a winding of a transformer inserted in the communication line and the noise removal signal generation unit. Adaptive common mode noise removal device for wire. The said noise removal signal application part is provided with the transformer which consists of the inductance inserted in each line of the said communication line, and the inductance connected to the said noise removal signal production | generation part. An adaptive common mode noise elimination device for communication lines as described in 1.

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