JP2015012364A - Communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication device that observes a signal having an object frequency.SOLUTION: According to an embodiment, a communication device performs communication with an external device by means of a power line. The communication device comprises first storage means, receiving means, calculation means, and second storage means. The second storage means stores information on an observation object frequency. The receiving means receives an electric signal of the power line from the power line. The calculation means calculates a frequency characteristic of electric characteristics of the electric signal, and calculates a physical quantity at the observation object frequency. The second storage means stores information on a signal strength.

Description

  The present embodiment relates to a communication device capable of communicating using a power line.

  Technological development for the purpose of increasing the functionality and efficiency of power systems and introducing distributed power sources such as solar power generation and storage batteries into power systems is actively underway. In order to increase the efficiency of the electric power system, it is necessary to grasp the state and improve the control, and communication technology is considered to be an indispensable technology. Wireless communication and power line carrier communication are being studied as communication technologies for power systems. Along with this, development of sensor network technology for collecting a large amount of sensor information in order to grasp and control a detailed state more efficiently has been advanced. Examples of sensor network use include environmental and ecosystem monitoring.

  In relation to environmental monitoring, how to reduce damage from natural disasters such as earthquakes has become an important theme since the Great East Japan Earthquake. Various studies have been conducted on earthquake prediction so far, and it is known that electromagnetic radiation is a predictive event when an earthquake occurs. Therefore, studies on earthquake prediction by detecting this electromagnetic wave are underway.

Masashi Hayakawa and two others “Electric phenomena and earthquake prediction associated with earthquakes” RF World No.4, CQ Publication 2008

  However, a special observation device equipped with an antenna, a signal processing unit, and the like is used to detect electromagnetic waves accompanying an earthquake. In order to improve the estimation accuracy of earthquake occurrence and estimate the location of earthquake occurrence, it is necessary to arrange observation devices for detecting electromagnetic waves over a wide area and to observe these electromagnetic waves constantly. This is difficult.

  Here, for the purpose of improving the efficiency of the power distribution system, introduction of smart meters in which a communication function is added to a watt-hour meter has been progressing. This is intended to collect power consumption and other information with a central device using a communication function installed in a smart meter, and to improve the efficiency of power transmission and distribution. If it is possible to give the function of an observation device to a smart meter, a system for detecting electromagnetic waves radiated in advance due to the occurrence of an earthquake can be widely arranged. However, incorporating elements that are essentially unnecessary, such as an antenna and a signal processing circuit as a function of the observation device, into the smart meter is not preferable because it increases the size and cost of the smart meter.

  Therefore, an object of the present invention is to provide a communication device that observes a signal of a target frequency.

  According to the embodiment, the communication device communicates with an external device using a power line. The communication apparatus includes a first storage unit, a reception unit, a calculation unit, and a second storage unit. The second storage means stores information on the frequency to be observed. The receiving means receives an electric signal of the power line from the power line. The calculation means calculates a frequency characteristic of an electric characteristic of the electric signal and calculates a physical quantity at the frequency to be observed. The second storage means stores the signal strength information.

1 is a block diagram showing a configuration as an example of a communication apparatus according to an embodiment. The block diagram which shows the detailed structure used as an example of the signal receiving part shown in FIG. The block diagram which shows the detailed structure used as an example of the signal transmission part shown in FIG. The block diagram which shows the detailed structure used as an example of the control part shown in FIG. The flowchart which shows the operation | movement which concerns on this embodiment. The schematic diagram which shows the frequency characteristic which concerns on this embodiment.

  Hereinafter, the present embodiment will be specifically described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration as an example of the communication apparatus 10 according to the present embodiment. The communication device 10 is connected to a pair of power lines 104 that transmit power. The communication device 10 uses the power line 104 to perform external communication (for example, other communication having the same function as the communication device 10) connected to the power line 104 by power line communication (PLC). Device). The communication device 10 performs power line carrier communication by superimposing an information signal on the power line 104. The power line 104 not only functions as a transmission line used for power line carrier communication, but also functions as an antenna that receives broadcast wave signals and electromagnetic waves radiated in advance due to the occurrence of an earthquake. The power line 104 is not limited as long as it is a cable that transmits power, such as an electric wire, a lead-in line, or a light line. The communication device 10 is connected to a smart meter having a measurement function that automatically measures the amount of power used by a consumer in which the communication device 10 is installed. Note that the communication device 10 may be a smart meter provided with the measurement function in the same element instead of a separate element.

The communication apparatus 10 includes a coupling unit 100, a signal receiving unit 101, a signal transmitting unit 102, and a control unit 103.
The coupling unit 100 connects the signal reception unit 101 and the signal transmission unit 102 to the power line 104. The coupling unit 100 has a high impedance at a transmission frequency (for example, 50 Hz) where power is transmitted through the power line 104. Therefore, coupling unit 100 prevents power from flowing to communication device 10 side. On the other hand, the coupling unit 100 1 has a low impedance at a communication frequency (for example, 10 kHz to 450 kHz) used for communication. That is, in the coupling unit 100, the impedance at a specific frequency higher than the transmission frequency is lower than the impedance at the transmission frequency.
The signal reception unit (reception unit) 101 receives and processes a signal sent from the external device to the communication device 10 via the power line 104. Furthermore, the signal receiving unit 101 receives and processes electrical characteristics (for example, voltage) of the electrical signal flowing through the power line 104 from the power line 104. The detailed configuration of the signal receiving unit 101 will be described later.
The signal transmission unit (transmission unit) 102 processes a signal transmitted from the communication device 10 to the external device via the power line 104, and transmits the processed signal to the external device. The detailed configuration of the signal transmission unit 102 will be described later.
The control unit 103 controls the operation of the communication device 10. A detailed configuration of the control unit 103 will be described later.
FIG. 2 is a block diagram illustrating a detailed configuration as an example of the signal receiving unit 101. The signal reception unit 101 includes an A (analog) / D (digital) conversion unit 201 and a reception signal adjustment unit 202 in order from the control unit 103 to the coupling unit 101. The A / D conversion unit 201 is means for converting an analog signal into a digital signal. The reception signal adjustment unit 202 includes a reception amplifier unit 203 and a reception filter unit 204. The reception amplifier unit 203 is a unit that adjusts the intensity of the signal so that the loss of information included in the signal is reduced as much as possible when the analog signal is converted into the digital signal using the A / D conversion unit 201. The reception filter unit 204 is a means for attenuating a signal having a frequency other than the frequency (or frequency band, frequency band) used for power line carrier communication and the frequency to be observed. The frequency to be observed is, for example, the frequency of a broadcast wave whose signal intensity fluctuates due to the occurrence of an earthquake (for example, a signal of a broadcast wave from a transmitting station such as AM / FM broadcast) or a precursor radiation due to the occurrence of an earthquake. The frequency of an electromagnetic wave (for example, an electromagnetic wave generated by at least one of the piezoelectric effect, rock destruction, electrokinetic phenomenon, etc.). In the present embodiment, such a signal having an observation target frequency is referred to as an observation target electromagnetic signal. That is, the reception filter unit (extraction means) 204 extracts a communication signal used for power line carrier communication and an electromagnetic signal to be observed.

  FIG. 3 is a block diagram illustrating a detailed configuration as an example of the signal transmission unit 102. The signal transmission unit 102 includes a D / A conversion unit 301 and a transmission signal adjustment unit 302 in order from the control unit 103 toward the coupling unit 100. The D / A converter 301 is means for converting a digital communication signal into an analog signal. The transmission signal adjustment unit 302 includes a transmission amplifier unit 303 and a transmission filter unit 304. The transmission amplifier unit 303 is a unit that adjusts signal strength and supplies a current to the power line 104 so that a communication signal can be transmitted using the power line 104. The transmission filter unit 304 is means for attenuating noise generated by the processing of the D / A conversion unit 301 or the processing of the transmission amplifier unit 303.

FIG. 4 is a block diagram illustrating a detailed configuration as an example of the control unit 103. As the control unit 103, for example, a microcontroller having a storage area such as a flash memory or an EEPROM (Electrically Erasable Programmable Read-Only Memory) can be used. The control unit 103 can be configured by, for example, an FPGA (Field Programmable Gate Array), a PLD (Programmable Logic Device), or the like. The control unit 103 includes a calculation processor unit 401, a frequency information holding unit 402, a signal strength calculation unit 403, a calculation result holding unit 404, and a clock unit 405.
The calculation processor unit 401 is a means for performing numerical calculations and calculations for control. The calculation processor unit 401 is a calculation unit in the microcontroller. When the control unit 103 is configured with an FPGA or a PLD, the calculation processor unit 401 is mounted as a circuit similar to an arithmetic unit similar to a microcontroller.

  The frequency information holding unit (storage unit) 402 is a unit that stores frequency information of an electromagnetic signal to be observed. The frequency information holding unit 402 can use a flash memory or an EEPROM.

  The signal strength calculation unit (calculation unit) 403 is a unit that calculates the frequency characteristic of the electrical characteristic acquired by the signal reception unit 101 from the power line 104. Further, the signal intensity calculation unit 403 is a means for calculating a physical quantity at the frequency of the electromagnetic signal to be observed stored in the frequency information holding unit 402. The physical quantity calculated by the signal strength calculation unit 403 is, for example, a signal strength (also referred to as an electrical signal strength) or a phase at the frequency of the electromagnetic signal to be observed. In the present specification, an example in which the signal strength calculation unit 403 calculates the signal strength as the frequency characteristic will be described as an example. The signal intensity calculation unit 403 can perform calculation using fast Fourier transform.

  The calculation result holding unit (storage unit) 404 is a unit that stores the calculation result of the signal strength calculation unit 403. The calculation result is, for example, the physical quantity itself at the frequency of the electromagnetic signal to be observed, or information on the amount of change from a certain reference value. The calculation result holding unit 404 can use a flash memory or an EEPROM. Note that the frequency information holding unit 402 and the operation result holding unit 404 can be different data areas of the same circuit element or different circuit elements.

  The clock unit 405 is a means for measuring time. The control unit 103 can recognize the current time by the clock unit 405. As the clock unit 405, an RTC (Real Time Clock) or the like can be used. That is, the calculation result holding unit 404 stores the calculation result (physical quantity information) in the signal intensity calculation unit 403 in association with the time when the signal intensity calculation unit 403 calculates the physical quantity at the frequency of the electromagnetic signal to be observed. can do.

  Next, the operation of the communication device 10 will be described. FIG. 5 is a flowchart showing the operation of the communication apparatus 10. Note that the communication device 10 is connected to the power line 104 and is in a state where an electric signal can be acquired from the power line 104.

  The signal receiving unit 101 acquires the electrical characteristics of the power line 104 (step S11). In step S <b> 11, the signal receiving unit 101 receives a power signal flowing through the power line 104 from the power line 104 and acquires an electrical characteristic from the power signal. Below, an electrical characteristic is demonstrated as a voltage.

  Next, the calculation processor unit 401 determines whether or not the frequency information of the electromagnetic signal to be observed is stored in the frequency information holding unit 402 (step S12). The frequency information is variable. Even if the frequency information is initially set, the frequency information may be rewritable based on information transmitted from an external device in power carrier communication.

  When the frequency information is not stored in the frequency information holding unit 402 (step S12, No), the calculation processor 401 controls to execute a normal communication operation (step S16). The normal communication operation is, for example, an operation of transmitting information such as power consumption to an external device through power carrier communication.

  When the frequency information is stored in the frequency information holding unit 402 (step S12, Yes), the signal strength calculating unit 403 calculates the frequency characteristics of the voltage acquired by the signal receiving unit 101 (step S13). In step S13, the signal strength calculation unit 403 calculates the frequency characteristic of the electric characteristic of the electric signal, and calculates a physical quantity at the frequency to be observed. That is, the communication apparatus 10 measures the physical quantity itself at the frequency of the electromagnetic signal to be observed or the amount of change from a certain reference value. At this time, the reception filter unit 204 functions to extract an electromagnetic signal to be observed from the electric signal. Next, the calculation processor unit 401 controls to execute a normal communication operation (step S14).

  Next, the control unit 10 stores the above-described calculation result by the signal strength calculation unit 403 in Step S13 in the calculation result holding unit 404 (Step S15). Thereafter, the signal transmission unit 102 may transmit calculation result information to an external device using the power line 104. In this case, the external device can use the calculation result to estimate the occurrence of the earthquake. An example of the estimation of the occurrence of an earthquake will be described later with reference to FIG. Note that the communication device 10 may estimate the occurrence of an earthquake using the calculation result by itself without transmitting the calculation result to the external device. Depending on the estimation result, the communication device 10 may sound an alarm on its own device, or may transmit alarm information to an external device using the power line 104. Note that the calculation of the physical quantity at the frequency to be observed by the communication device 10 may be executed at an arbitrary timing regardless of the normal communication operation in step S14.

  Next, an example of estimating the occurrence of an earthquake will be described. FIG. 6 is a schematic diagram showing the frequency characteristics calculated in step S13 of FIG. The horizontal axis represents frequency, and the vertical axis represents signal strength (electric field strength). Here, the frequency characteristics of the broadcast wave signal will be described as an example. It is assumed that the frequency of the broadcast wave signal is lower than the frequency of the communication signal used for power line carrier communication.

  The solid line graph shows the frequency characteristics of the broadcast wave signal at the normal time. The normal time is when the broadcast wave signal is not affected by ionospheric disturbances that occur before the earthquake. The dotted line graph shows the frequency characteristics of broadcast wave signals affected by ionospheric disturbances before the earthquake. The signal strength of the broadcast wave signal affected by the ionospheric disturbance is lower than the signal strength of the broadcast wave signal at the normal time. In other words, ionospheric disturbances that occur before the occurrence of an earthquake affect the propagation of broadcast wave signals and fluctuate the signal strength of broadcast wave signals.

  Note that the signal strength of the broadcast wave signal affected by the ionospheric disturbance may be higher than the signal strength of the broadcast wave signal at the normal time. The frequency of the broadcast wave signal may be higher than the frequency of the communication signal used for power line carrier communication. The frequency of the broadcast wave signal may overlap with the frequency of the communication signal used for power line carrier communication. In this case, after confirming that the communication signal is not transmitted through the power line 104, the control unit 103 may execute the calculation of the frequency characteristics of the electrical characteristics by the signal strength calculation unit 403 as in step S13. . In FIG. 6, the frequency characteristic of the broadcast wave signal has been described as an example, but the same applies to other electromagnetic signals to be observed. In other words, the change in the electromagnetic signal is not only a change in the signal intensity of the broadcast wave caused by the disturbance of the ionosphere, but also the electromagnetic wave generated by at least one of the piezoelectric effect, rock destruction, electrokinetic phenomenon, etc. It may be a change in signal strength.

  Next, the effect of this embodiment will be described. By using the power line 104 as an antenna that receives an electromagnetic signal to be observed, the communication apparatus 10 according to the present embodiment can observe the electromagnetic signal to be observed and acquire data. The communication device 10 functions as an observation device for an electromagnetic signal to be observed by simply changing the software without adding an antenna or a special signal processing circuit required for observing the electromagnetic signal to be observed. Is possible. Since a plurality of communication devices 10 can be installed as a smart meter or together with a smart meter, the communication device 10 can be used for improving the estimation accuracy of an earthquake occurrence and estimating an earthquake occurrence position.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 10 ... Communication apparatus, 100 ... Coupling part, 101 ... Signal receiving part, 102 ... Signal transmission part, 103 ... Control part, 104 ... Power line, 201 ... A / D conversion part, 202 ... Reception signal adjustment part, 203 ... Reception amplifier 204, reception filter unit, 301 ... D / A conversion unit, 302 ... transmission signal adjustment unit, 303 ... transmission amplifier unit, 304 ... transmission filter unit, 401 ... calculation processor unit, 402 ... frequency information holding unit, 403 ... Signal strength calculation unit, 404... Operation result holding unit, 405.

Claims (7)

In a communication device that communicates with an external device using a power line,
First storage means for storing information on the frequency to be observed;
Receiving means for receiving electrical characteristics of the power line from the power line;
A computing means for computing a frequency characteristic of the electrical characteristic and computing a physical quantity at the frequency to be observed;
Second storage means for storing the physical quantity information;
A communication device comprising:   The communication apparatus according to claim 1, wherein the frequency to be observed is a frequency of a broadcast wave.   The communication apparatus according to claim 1, wherein the frequency to be observed is a frequency of an electromagnetic wave generated by at least one of a piezoelectric effect, rock destruction, and an electrokinetic phenomenon.   The communication apparatus according to claim 1, further comprising: a transmission unit that transmits the physical quantity information to the external apparatus using the power line.   The communication apparatus according to claim 1, further comprising an extraction unit configured to extract a signal having a frequency to be observed from the electrical characteristics.   The communication apparatus according to claim 1, wherein the physical quantity is signal intensity at a frequency to be observed. It further includes a clock unit that measures time,
The second storage means stores the information on the physical quantity in association with the time when the calculating means calculates the physical quantity.
The communication apparatus according to claim 1.

Images