JP2019216387A - Communication device - Google Patents

Abstract

To provide a technology to prevent a deterioration in quality of a signal while reducing the influence of disturbance even when a plurality of types of connection forms are possible.SOLUTION: A load 20 is connected to a first power line 10. A first protection circuit 22 is connected to the first power line 10. A communication unit 30 is connected to a second power line 12. A second protection circuit 32 is connected to the second power line 12. A switch 52 switches between a first mode for connecting before grounding the first protection circuit 22 and second protection circuit 32, and a second mode for cutting off the connection between the first protection circuit 22 and second protection circuit 32 and grounding any one of the first protection circuit 22 and second protection circuit 32. When the first power line 10 and second power line 12 are connected to the same external power supply, the switch 52 switches to the second mode.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to communication technology, and particularly to a communication device that executes power line communication.

  In power line communication, a communication signal is superimposed using a power line as a medium. Communication devices for power line communication are required to have resistance to common mode noise. In order to increase resistance to common mode noise, for example, a common mode choke coil is connected (for example, see Patent Document 1).

JP 2014-30167 A

  The communication device includes a load that consumes the supplied power and a communication unit that performs power line communication. In such a communication device, another wire is connected to the load and the communication unit (hereinafter, referred to as a “first connection mode”), or the same wire is branched and connected to the load and the communication unit. (Hereinafter, referred to as “second connection mode”). On the other hand, a communication device is provided with a protection circuit to protect the communication device from disturbances such as ESD (Electro-Static Discharge), surge, and burst noise. In the case where protection circuits are connected to each of the load and the communication unit in consideration of the first connection form, in the second connection form, two protection circuits are connected to one wiring, The signal quality deteriorates.

  The present disclosure has been made in view of such a situation, and an object of the present disclosure is to provide a technique for suppressing deterioration of signal quality while reducing the influence of disturbance even when a plurality of types of connection forms are possible. It is in.

  In order to solve the above-described problems, a communication device according to an aspect of the present disclosure includes a load connected to a first power line and receiving power from an external power supply, and a first device connected to the first power line and protecting the load from disturbance. A protection circuit, a communication unit connected to the second power line and performing power line communication, a second protection circuit connected to the second power line and protecting the communication unit from disturbance, a first protection circuit and a second protection circuit And a second mode in which the connection between the first protection circuit and the second protection circuit is disconnected and one of the first protection circuit and the second protection circuit is grounded. And a switch for changing over. The switch switches to the second mode when the first power line and the second power line are connected to the same external power supply.

  According to the present disclosure, even when a plurality of types of connection forms are possible, deterioration of signal quality can be suppressed while reducing the influence of disturbance.

FIG. 2 is a diagram illustrating a configuration of a communication device according to the first embodiment. FIG. 2 is a diagram illustrating a configuration of a communication unit in FIG. 1. FIGS. 3A and 3B are diagrams showing configurations of the first protection circuit and the second protection circuit of FIG. FIGS. 4A and 4B are diagrams showing an outline of the operation of the communication device of FIG. FIG. 9 is a diagram illustrating a configuration of a communication device according to a second embodiment. FIG. 6 is a diagram illustrating a data structure of a table held by a control unit in FIG. 5. FIG. 9 is a diagram illustrating a configuration of a communication device according to a third embodiment.

(Example 1)
Before specifically describing an embodiment of the present disclosure, an outline of the present embodiment will be described. The present embodiment relates to a communication device that executes power line communication. The communication device corresponds to, for example, a controller or a slave terminal that communicates power information or sensor data in a HEMS (Home Energy Management System) or a smart meter system. In power line communication, a signal is superimposed on a power line. As described above, the communication device includes the load and the communication unit, and the connection between the load and the communication unit is made in the first connection mode or the second connection mode. In the first connection mode, the first power line connected to the load and the second power line connected to the communication unit are connected to different power sources. On the other hand, in the second connection mode, since the second power line branches off from the first power line, the first power line and the second power line are connected to the same power supply.

  Transient voltages and currents due to static electricity discharge or intermittent switches cause disturbances such as ESD, surge, and burst noise. Such a disturbance has a voltage or a current that is much larger than a voltage or a current in a normal circuit operation, and may cause a circuit to malfunction or be destroyed. A protection circuit is used to protect the load and the communication unit from such disturbance. In consideration of the first connection mode, when protection circuits are connected to each of the load and the communication unit, in the second connection mode, two protection circuits are connected to one wiring. Here, the signal of the power line communication has a frequency band of, for example, 1 MHz to 30 MHz, and has a frequency band higher than the commercial power frequency of 50 Hz or 60 Hz of the power. Therefore, when two protection circuits are connected to one wiring, the quality of a signal deteriorates due to the influence of the capacitance of the two protection circuits. Deterioration of signal quality limits the number of slave terminals that can be connected to the HEMS or smart meter system.

  The present embodiment aims at suppressing deterioration of signal quality while reducing the influence of disturbance in a communication device capable of the first connection mode and the second connection mode. For this purpose, the communication device according to the present embodiment is provided with a switch for enabling or disabling one protection circuit. The switch is switched according to the first connection mode or the second connection mode. For example, in the case where the first protection circuit is connected to the load and the second protection circuit is connected to the communication device, in the first connection mode, both the first protection circuit and the second protection circuit are used. Be activated. On the other hand, in the second connection mode, for example, the second protection circuit is invalidated. Therefore, the influence of disturbance is reduced by the first protection circuit, and the influence of the second protection circuit is reduced, so that deterioration of signal quality is suppressed.

  FIG. 1 shows a configuration of the communication device 100. Communication device 100 is connected to first power line 10 and second power line 12. The communication device 100 includes a first terminal 14, a second terminal 16, a load 20, a first protection circuit 22, a communication unit 30, a second protection circuit 32, a first connection line 40, a second connection line 42, and a third connection line. 44, a connection point 46, a ground 48, an operation unit 50, and a switch 52.

  An AC voltage from an external power supply (not shown) is applied to the pair of first power lines 10. The AC voltage is, for example, 100 [V] or 200 [V]. Power having such an AC voltage is also called commercial power, and has the above-described commercial power frequency. The pair of first terminals 14 connect the pair of first power lines 10 outside the communication device 100. The pair of first terminals 14 also connect a pair of wires inside the communication device 100, but this pair of wires is also referred to as a pair of first power lines 10 below. Further, the pair of first power lines 10 and the pair of first terminals 14 may be referred to as a first power line 10 and a first terminal 14.

  The load 20 is a circuit or an element that is connected to the pair of first power lines 10 in the communication device 100, receives power from an external power supply, and consumes the received power. For example, the load 20 converts AC power into DC power by an AC (Alternating Current) / DC (Direct Current) converter, and then operates the communication device 100 based on the DC power. The load 20 is not limited to this, and may be any load.

  In FIG. 1, two types of second power lines 12 are shown as a pair of second power lines 12. The first is a pair of second power lines 12 indicated by a dotted line, which is the pair of second power lines 12 in the first connection configuration described above. In this case, an AC voltage from an external power supply (not shown) different from an external power supply (not shown) that applies an AC voltage to the pair of first power lines 10 is applied to the pair of second power lines 12. . On the other hand, the second is a pair of second power lines 12 branched from points P1 and P2 in the pair of first power lines 10, and is a pair of second power lines 12 in the above-described second connection configuration. In this case, an AC voltage from an external power supply (not shown) that applies an AC voltage to the pair of first power lines 10 is applied to the pair of second power lines 12.

  The pair of second terminals 16 connect the pair of second power lines 12 outside the communication device 100. The pair of second terminals 16 connect a pair of wirings inside the communication device 100, but this pair of wirings is also referred to as a pair of second power lines 12 below. Further, the pair of second power lines 12 and the pair of second terminals 16 may be referred to as a second power line 12 and a second terminal 16.

  The communication unit 30 is connected to the pair of second power lines 12 in the communication device 100 and executes power line communication. FIG. 2 is a diagram illustrating a configuration of the communication unit 30. The communication unit 30 includes a common mode choke coil 70, a capacitor 72, a primary coil 74, a secondary coil 76, a transmission circuit 78, and a reception circuit 80. A common mode choke coil 70 is connected to the pair of second power lines 12. The common mode choke coil 70 has a function of attenuating the common mode noise toward the receiving circuit 80 and a function of attenuating the common mode noise that goes out of the transmitting circuit 78 to the outside. The common mode choke coil 70 has, for example, a structure in which a pair of second power lines 12 is wound around one core (not shown). The common mode choke coil 70 is connected to a primary coil 74 via a pair of capacitors 72.

  Primary coil 74 is arranged opposite secondary coil 76, and these constitute a transformer. The secondary coil 76 connects the transmission circuit 78 and the reception circuit 80 in parallel. The pair of capacitors 72 has high impedance with respect to AC power supplied via the pair of second power lines 12, and has low impedance with respect to a signal using a frequency band of 1 MHz to 30 MHz. That is, the pair of capacitors 72 transmits a signal in a frequency band used for power line communication and blocks a signal in a frequency band used for AC power. The transmission circuit 78 executes transmission processing in power line communication, and the reception circuit 80 executes reception processing in power line communication. Returning to FIG.

  The first protection circuit 22 is connected to points P3 and P4 on the pair of first power lines 10. The first protection circuit 22 protects the load 20 from disturbances such as ESD, surge, and burst noise. The first connection line 40 is connected to the first protection circuit 22. The second protection circuit 32 is connected to points P5 and P6 on the pair of second power lines 12. The second protection circuit 32 protects the communication unit 30 from disturbances such as ESD, surge, and burst noise. The second connection line 42 is connected to the second protection circuit 32. The switch 52 is disposed on the second connection line 42. The switch 52 is connected to the operation unit 50, and connects and disconnects the second connection line 42 according to a user operation on the operation unit 50. The switch 52 is an interface that can be manually operated by the user. The switch 52 may be arranged on the first connection line 40 instead of the second connection line 42. The first connection line 40 extending from the first protection circuit 22 and the second connection line 42 extending from the second protection circuit 32 are connected at a connection point 46. The third connection line 44 connects the connection point 46 and the ground 48.

  FIGS. 3A and 3B show the configuration of the first protection circuit 22 and the second protection circuit 32. FIG. FIG. 3A shows the configuration of the first protection circuit 22. The first protection circuit 22 includes a first varistor V1, a second varistor V2, and a first arrester A1. A first varistor V1 is arranged on a line connected to the point P3, a second varistor V2 is arranged on a line connected to the point P4, and a first connection line 40 extends from a connection point of these lines. The first arrestor A1 is disposed on the first connection line 40, and the ground 48 is connected via the third connection line 44 as shown in FIG. That is, the first arrester A1 is disposed between the connection point and the ground 48.

  The first varistor V1 and the second varistor V2 are electronic components having two electrodes. When the voltage between the two terminals is low, the electric resistance increases, and when the voltage between the two terminals becomes higher than a certain level, the electric current rapidly increases. It has the property of reducing resistance. The first arrester A1 is a surge protection element using discharge, and starts discharging when a surge voltage exceeds a discharge starting voltage. The surge immunity of the first arrester A1 is larger than the surge immunity of the first varistor V1 and the second varistor V2.

  FIG. 3B shows the configuration of the second protection circuit 32. The second protection circuit 32 includes a third varistor V3, a second arrester A2, a third arrester A3, and a fourth arrester A4. A third varistor V3 is arranged on a wiring connecting point P5 and point P6. The second arrester A2 is arranged on the wiring connected to the point P5, the third arrester A3 is arranged on the wiring connected to the point P6, and the second connection line 42 extends from the connection point of these wirings. A fourth arrester A4 is arranged on the second connection line 42, and a ground 48 is connected via the third connection line 44 as shown in FIG. That is, the fourth arrester A4 is arranged between the connection point and the ground 48.

  Hereinafter, the operation of the communication device 100 in the first connection mode and the second connection mode will be described with reference to FIGS. 4A and 4B show an outline of the operation of the communication device 100. FIG. FIG. 4A shows the operation in the first connection mode. The configuration of the communication device 100 is shown in the same manner as FIG. 1, but a pair of first power lines 10 and the like are shown as one first power line 10 and the like. In the first connection configuration, as described above, the first power line 10 and the second power line 12 are not connected to the same external power supply. In this case, the switch 52 connects the second connection line 42 by the operation of the operation unit 50. Thus, the first protection circuit 22 and the second protection circuit 32 are connected via the first connection line 40 and the second connection line 42, and then connected to the ground 48 via the third connection line 44. Is grounded. Such a connection relationship between the first protection circuit 22, the second protection circuit 32, and the ground 48 is called a first mode.

  In the first mode, the disturbance input to the first power line 10 flows from the first protection circuit 22 to the ground 48 via the first connection line 40 and the third connection line 44. The disturbance input to the second power line 12 flows from the second protection circuit 32 to the ground 48 via the second connection line 42 and the third connection line 44. As described above, by enabling the first protection circuit 22 and the second protection circuit 32, any one of the disturbance inputted to the first power line 10 and the disturbance inputted to the second power line 12 can be prevented. Also, the load 20 and the communication unit 30 are protected. On the other hand, since only one protection circuit is provided for the path connecting the first power line 10 to the ground 48 and the path connecting the second power line 12 to the ground 48, the signal quality is not deteriorated.

  FIG. 4B shows an operation in the second connection mode. The configuration of the communication device 100 is shown in the same manner as FIG. In the second connection configuration, as described above, the first power line 10 and the second power line 12 are connected to the same external power supply. In this case, the switch 52 disconnects the second connection line 42 by the operation of the operation unit 50. The connection between the first protection circuit 22 and the second protection circuit 32 is disconnected, and only the first protection circuit 22 is connected to the ground 48 via the first connection line 40 and the third connection line 44, thereby being grounded. . Such a connection relationship between the first protection circuit 22, the second protection circuit 32, and the ground 48 is called a second mode.

  In the first mode, the disturbance input to the first power line 10 flows from the first protection circuit 22 to the ground 48 via the first connection line 40 and the third connection line 44. Therefore, the disturbance input to the first power line 10 does not flow to the communication unit 30. By activating the first protection circuit 22 in this manner, the load 20 and the communication unit 30 are protected against a disturbance input to the first power line 10. On the other hand, since only one protection circuit is provided on the path from the first power line 10 to the ground 48, the signal quality is not deteriorated.

  According to the present embodiment, in the first connection mode, the first protection circuit 22 and the second protection circuit 32 are enabled, so that the disturbance input to the first power line 10 and the input to the second power line 12 The load 20 and the communication unit 30 can be protected against any disturbance. Further, in the first connection mode, only one protection circuit is provided for the path connecting the first power line 10 to the ground 48 and the path connecting the second power line 12 to the ground 48, so that the signal quality is improved. Deterioration can be suppressed. Further, in the second connection mode, the first protection circuit 22 is enabled and the second protection circuit 32 is disabled, so that the load 20 and the communication unit 30 are connected to the disturbance input to the first power line 10. Can be protected. Further, in the second connection mode, only one protection circuit is disposed on the path from the first power line 10 to the ground 48, so that deterioration of signal quality can be suppressed.

  As described above, even if a plurality of types of connection forms are possible, deterioration of signal quality can be suppressed while reducing the influence of disturbance. In addition, since deterioration of signal quality is suppressed, the number of connected terminals can be increased. Further, since the switch 52 is arranged on one of the first connection line 40 and the second connection line 42, the first mode or the second mode can be realized by connecting or disconnecting the switch 52. Further, since the operation unit 50 is provided, the switch 52 can be operated.

  The outline | summary of 1 aspect of this indication is as follows. The communication device 100 according to an aspect of the present disclosure includes a load 20 connected to the first power line 10 and receiving power from an external power supply, and a first protection circuit 22 connected to the first power line 10 and protecting the load 20 from disturbance. A communication unit 30 connected to the second power line 12 to execute power line communication; a second protection circuit 32 connected to the second power line 12 to protect the communication unit 30 from disturbance; The first protection circuit 22 and the second protection circuit 32 by disconnecting the first protection circuit 22 and the second protection circuit 32 by disconnecting the first protection circuit 22 and the second protection circuit 32. A switch 52 for switching between the first mode and the second mode in which one of them is grounded. The switch 52 switches to the second mode when the first power line 10 and the second power line 12 are connected to the same external power supply.

  The switch 52 may switch to the first mode when the first power line 10 and the second power line 12 are not connected to the same external power supply.

  A first connection line 40 extending from the first protection circuit 22, a second connection line 42 extending from the second protection circuit 32, and a connection point 46 between the first connection line 40 and the second connection line 42 and a ground 48 are connected. A third connection line 44 may be further provided. The switch 52 may be arranged on one of the first connection line 40 and the second connection line 42.

  An operation unit 50 that can operate the switch 52 may be further provided.

(Example 2)
Next, Example 2 will be described. The second embodiment relates to a communication device that executes power line communication as in the first embodiment. The communication device includes a switch that enables the first protection circuit and the second protection circuit in the first connection mode and disables the second protection circuit in the second connection mode. In the first embodiment, the user manually operates the switch. On the other hand, in the second embodiment, the switching of the switches is automated. Here, it demonstrates centering on the difference with Example 1. FIG.

  FIG. 5 shows a configuration of the communication device 100. The communication device 100 does not include the operation unit 50 as compared with the communication device 100 of FIG. 1 and includes a voltage detection unit 60 and a control unit 62. The voltage detection unit 60 is connected to a point P7 on the first power line 10 and connected to a point P8 on the second power line 12. The voltage detection unit 60 detects the voltage value of the AC voltage on the first power line 10 as a first voltage, and detects the voltage value of the AC voltage on the second power line 12 as a second voltage. Since a known technique may be used for detecting the first voltage and the second voltage, the description is omitted here.

  The control unit 62 receives the first voltage and the second voltage detected by the voltage detection unit 60. The control unit 62 subtracts the second voltage from the first voltage, and acquires the absolute value of the subtraction result as a difference. In addition, the control unit 62 holds a table in which the operation for the difference is indicated. FIG. 6 shows a data structure of a table held in the control unit 62. The control unit 62 determines the operation of the switch 52 according to the conditions shown in the table. For example, if the difference is greater than the threshold, switch 52 is connected, and if the difference is less than or equal to the threshold, switch 52 is disconnected. Referring back to FIG.

  In the case of the first connection mode, since a different external power supply is connected to the first power line 10 and the second power line 12, the difference between the first voltage and the second voltage increases. Therefore, in such a case, the first mode is set. On the other hand, in the case of the second connection mode, since the same external power supply is connected to the first power line 10 and the second power line 12, the difference between the first voltage and the second voltage is reduced. Therefore, in such a case, the second mode is set. The control unit 62 switches the switch 52 according to the determined content.

  According to the present embodiment, since the switch 52 is switched based on the difference between the first voltage on the first power line 10 and the second voltage on the second power line 12, the switching of the switch 52 can be automated. If the difference is larger than the threshold value, the switch 52 is connected, and if the difference is equal to or smaller than the threshold value, the switch 52 is disconnected.

  The outline | summary of 1 aspect of this indication is as follows. A voltage detector 60 for detecting a first voltage on the first power line 10 and a second voltage on the second power line 12, and a switch based on a difference between the first voltage and the second voltage detected by the voltage detector 60. And a control unit 62 for switching between the two.

Example 3
Next, a third embodiment will be described. Third Embodiment A third embodiment relates to a communication device that executes power line communication as before. The communication device includes a switch that enables the first protection circuit and the second protection circuit in the first connection mode and disables the second protection circuit in the second connection mode. In the third embodiment, the switching of the switches is automated as in the second embodiment. Here, it demonstrates centering on the difference from before.

  FIG. 7 shows a configuration of the communication device 100. The communication device 100 does not include the voltage detection unit 60 but includes a phase detection unit 64 as compared with the communication device 100 of FIG. The phase detection unit 64 is connected to a point P7 on the first power line 10 and connected to a point P8 on the second power line 12. The phase detection unit 64 detects the phase of the AC power on the first power line 10 as the first phase, and detects the phase of the AC power on the second power line 12 as the second phase. A known technique may be used for the detection of the first phase and the second phase, and a description thereof will be omitted.

  The control unit 62 receives the first phase and the second phase detected by the phase detection unit 64. The control unit 62 subtracts the second phase from the first phase, and acquires the absolute value of the result of the subtraction as a difference. In addition, the control unit 62 holds a table in which the operation for the difference is indicated. The table is the same as in FIG.

  In the case of the first connection mode, since a different external power supply is connected to the first power line 10 and the second power line 12, a difference between the first phase and the second phase becomes large. Therefore, in such a case, the first mode is set. On the other hand, in the case of the second connection mode, since the same external power supply is connected to the first power line 10 and the second power line 12, the difference between the first phase and the second phase is reduced. Therefore, in such a case, the second mode is set. The control unit 62 switches the switch 52 according to the determined content.

  According to the present embodiment, the switch 52 is switched based on the difference between the first phase in the first power line 10 and the second phase in the second power line 12, so that the switching of the switch 52 can be automated. If the difference is larger than the threshold value, the switch 52 is connected, and if the difference is equal to or smaller than the threshold value, the switch 52 is disconnected.

  The outline | summary of 1 aspect of this indication is as follows. A phase detection unit 64 that detects a first phase in the first power line 10 and a second phase in the second power line 12, and a switch based on a difference between the first phase and the second phase detected by the phase detection unit 64. And a control unit 62 for switching between the two.

  The present disclosure has been described based on the embodiments. This embodiment is an exemplification, and it is understood by those skilled in the art that various modifications can be made to each of those components or combinations of processing processes, and such modifications are also within the scope of the present disclosure. .

  In the first to third embodiments, in the first connection mode, an external power supply different from the external power supply connected to the first power line 10 is connected to the second power line 12. However, the present invention is not limited to this. For example, the second power line 12 may be a dedicated line for power line communication. The second power line 12 may be a wiring branched from the first power line 10 by a non-contact coupling circuit such as a ferrite core. This corresponds to a configuration in which a signal flows into the first power line 10 in a non-contact manner. According to this modification, the degree of freedom of configuration can be improved.

  In the second embodiment, the control unit 62 subtracts the second voltage from the first voltage, and acquires an absolute value of the subtraction result as a difference. However, the control unit 62 may obtain a result obtained by dividing the first voltage by the second voltage as a difference. At this time, if the difference is within a predetermined range including “1”, the switch 52 is turned off, and if the difference is not within the range, the switch 52 is connected. According to this modification, the degree of freedom of configuration can be improved.

  DESCRIPTION OF SYMBOLS 10 1st power line, 12 2nd power line, 14 1st terminal, 16 2nd terminal, 20 load, 22 1st protection circuit, 30 communication part, 32 2nd protection circuit, 40 1st connection line, 42 2nd connection line , 44 third connection line, 46 connection point, 48 ground, 50 operation section, 52 switch, 70 common mode choke coil, 72 capacitor, 74 primary coil, 76 secondary coil, 78 transmission circuit, 80 reception circuit, 100 communication apparatus.

Claims (6)

A load connected to the first power line and receiving power from an external power supply;
A first protection circuit connected to the first power line and protecting the load from disturbance;
A communication unit connected to the second power line and performing power line communication;
A second protection circuit connected to the second power line and protecting the communication unit from disturbance;
A first mode in which the first protection circuit and the second protection circuit are connected and then grounded, and a connection between the first protection circuit and the second protection circuit is cut off, and the first protection circuit A switch for switching between a second mode in which one of the second protection circuit and the second protection circuit is grounded,
The communication device, wherein the switch switches to the second mode when the first power line and the second power line are connected to the same external power supply.   The communication device according to claim 1, wherein the switch switches to the first mode when the first power line and the second power line are not connected to the same external power supply. A first connection line extending from the first protection circuit;
A second connection line extending from the second protection circuit;
A third connection line that connects a connection point between the first connection line and the second connection line to a ground;
The communication device according to claim 1, wherein the switch is disposed on one of the first connection line and the second connection line.   The communication device according to claim 1, further comprising an operation unit that can operate the switch. A first voltage on the first power line, a voltage detection unit for detecting a second voltage on the second power line,
4. The control device according to claim 1, further comprising: a control unit configured to switch the switch based on a difference between the first voltage and the second voltage detected by the voltage detection unit. 5. The communication device according to claim 1. A first phase in the first power line and a phase detection unit that detects a second phase in the second power line;
4. The control device according to claim 1, further comprising: a control unit configured to switch the switch based on a difference between the first phase and the second phase detected by the phase detection unit. 5. The communication device according to claim 1.

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