JP2007006371A - Relay adaptor for power line communication and wiring structure thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact relay adaptor that can reduce the effect of noise and an impedance loss due to connection to an electric apparatus in a subscriber's house and can be manufactured inexpensively. <P>SOLUTION: A relay adaptor 1 for power line communication includes: a plug 6 connectable to a power socket 2 of a power line 3 on which a communication signal for information communication is superimposed; a plurality of pairs of branch lines 11, 12 branched from the plug 6; and a plurality of sockets 8, 10 respectively connected to the branch lines 11, 12, wherein the socket 8 is a MODEM socket 8 to which a PLC MODEM 7 is connected, and the socket 10 is an apparatus socket 10 to which an electric apparatus 9 other than the PLC MODEM 7 is connected. The length of the branch lines 12 connecting the plug 6 to the apparatus socket 10 is selected longer than the length of the branch lines 11 connecting the plug 6 to the MODEM socket 8 so as to prevent an impedance drop associated with connection of the electric apparatus 9 to the apparatus socket 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a relay adapter for power line communication that uses a power line as a communication medium for information communication, and a wiring structure thereof.

  A power line communication system (hereinafter referred to as a PLC system) has a high frequency signal (as high as several kHz to several tens of MHz or higher) as a communication signal on a power line through which a commercial current of a commercial frequency (generally 50 Hz or 60 Hz) flows. Communication is performed by superimposing. Such a PLC can transmit and receive a large amount of data by using an existing power line (also called a distribution line or a light line) drawn into each house without using a dedicated communication line. It is attracting attention as.

In the above PLC system, communication signals are conveyed using power lines, and in order to ensure a good normal state, sufficient signal strength and low noise are required. Since various electrical devices such as network terminals are connected, the communication signal may be affected by a decrease in impedance associated with the connection of these devices.
Thus, conventionally, for example, a wiring structure using the relay adapter 22 shown in FIGS. 5 and 6 has been considered.

Among these, in the wiring structure shown in FIG. 5 (see Patent Document 1), an electrical device 23 is connected to one outlet 24 via a relay adapter 22 having a blocking filter 21 having a low-pass filter characteristic therein, and a PLC modem 25 is connected. By connecting to the other outlet 26, it is possible to prevent a reduction in impedance due to the connection of the electric device 23 and to block high-frequency noise generated in the electric device 23.
On the other hand, in the wiring structure shown in FIG. 6, a relay adapter 22 to which a modem socket 32 is further added is used. That is, the adapter 22 includes a plug 29 connectable to an outlet 24, a pair of branch lines 30 and 31 branched from the plug 29, and two sockets 32 and 32 respectively connected to the branch lines 30 and 31, respectively. 33.

One of the sockets 32 and 33 is a modem socket 32 to which the PLC modem 25 is connected, and the other socket 33 is a device socket 33 to which the electric device 23 is connected. The blocking filter 21 having the low-pass filter characteristic is provided on a branch line 30 that connects the plug 29 and the device socket.
Therefore, in the wiring structure using the relay adapter 22 shown in FIG. 6, both the electrical device 23 and the PLC modem 25 can be connected even when there is only one outlet 24, and the relay adapter 22 is provided in the relay adapter 22. The filter 21 can block high frequency noise generated in the electrical device 23.

Japanese Patent Laid-Open No. 10-65583 (FIGS. 1 and 2)

In the conventional relay adapter 22, the blocking filter 21 is configured by an LC circuit. Therefore, an inductor (coil) that configures the circuit is limited in current capacity. For example, a vacuum cleaner or a dryer cannot be connected. On the other hand, when the allowable current capacity of the inductor is increased, the inductor itself is increased in size, and there is a problem that the relay adapter 22 including the blocking filter 21 must be increased in size and cost.
In addition, since the blocking filter 21 made of the conventional LC circuit uses a capacitor, there is a possibility that the capacitor may cause dielectric breakdown. Therefore, adding a fuse or the like to avoid this further increases the size and cost.

Furthermore, in the case of an AC adapter with a built-in power supply, such as a charger for a mobile phone, the AC cord is not provided because the plug (plug) of the outlet projects directly from the housing and is not provided with an AC cord. There is also a problem that communication signals in the power line are sucked into the AC adapter side compared to a normal AC adapter extending from the housing.
Therefore, a first object of the present invention is to provide a relay adapter that can reduce the influence of noise and impedance loss due to the connection of electrical equipment in a home, and that can be manufactured in a compact and low-cost manner.

By the way, in general, in a power line for commercial power supply, in either case of two-wire type or three-wire type, one of the wires is a neutral wire (grounded wire) and the other wire is a non-grounded wire. Therefore, the high-frequency communication signal superimposed on the power line is in an unbalanced state.
For this reason, a leakage electric field is generated around the power line by the communication signal transmitted from the PLC modem 25, which may affect a wireless device using the same frequency band.

However, since the conventional relay adapter 22 employs the blocking filter 21 composed of an LC circuit that attenuates noise and communication signals in normal mode, a common that flows in the same direction to the power line (neutral line and non-ground line). The mode current cannot be reduced. For this reason, a decrease in balance due to the connection of the electric equipment 23 cannot be suppressed, and a leakage electric field due to a communication signal from the PLC modem 25 cannot be reduced.
Therefore, a second object of the present invention is to provide a relay adapter capable of preventing a leakage electric field by suppressing a decrease in the balance of power lines due to the connection of electrical equipment in the house.

In order to achieve the first object, the present invention takes the following technical means.
That is, the present invention provides a plug that can be connected to an outlet of a power line on which a communication signal for information communication is superimposed, a plurality of pairs of branch lines branched from the plug, and a plurality of branches connected to the respective branch lines. A plurality of sockets, and the plurality of sockets are configured for a power line communication including a modem socket to which a PLC modem is connected and a device socket to which an electrical device other than the PLC modem is connected. In the relay adapter of
By making the length of the branch line connecting the plug and the device socket longer than the length of the branch line connecting the plug and the modem socket, the impedance associated with the connection of the electrical device to the device socket is reduced. It is characterized in that a decrease is prevented.

According to the present invention described above, the length of the branch line connected to the socket for the device is lengthened, and the decrease in impedance due to the connection of the electrical device to the socket is prevented, so that the communication signal in the power line is transmitted to the electrical device. Attenuation of the communication signal due to the suction to the side is suppressed, and a decrease in communication performance due to the connection of the electrical equipment is prevented.
Further, since it is not necessary to provide an inductor or a capacitor unlike a conventional relay adapter with a built-in blocking filter, a relay adapter with a filter function can be manufactured at low cost.
In addition, in order to secure the impedance sufficient to prevent leakage of communication signals to the power supply equipment side with the length of the branch line, for example, in the case of a 1.6 mm flat cord, there is about 0.5 to 2.0 m. I have confirmed that it should be.

Another invention for achieving the first object includes a plug connectable to an outlet of a power line on which a communication signal for information communication is superimposed, a plurality of pairs of branch lines branched from the plug, A plurality of sockets connected to each branch line, the plurality of sockets being a modem socket to which a PLC modem is connected and a device socket to which an electrical device other than the PLC modem is connected In the relay adapter for power line communication composed of
A normal mode choke coil is connected to a branch line connecting the plug and the device socket.

In this case, since the normal mode choke coil is connected to the branch line connected to the socket for the device, the normal mode impedance (differential impedance) of the branch line is increased by the ferrite core of the choke coil, and noise generated from the electric device Is blocked to improve the communication performance of the PLC modem.
Further, in the present invention, it is only necessary to provide a normal mode choke coil inside the relay adapter, and it is not necessary to provide an inductor or a capacitor. Therefore, a relay adapter with a filter function can be manufactured at low cost.

By the way, in the case of the relay adapter adopting the normal mode choke coil, when an electrical device having a relatively large current consumption is connected to the device socket, magnetic saturation occurs in the ferrite core of the choke coil due to the commercial current. Noise removal performance may deteriorate.
In order to prevent such magnetic saturation, it is common to provide an air gap in the ferrite core, but this also reduces the normal mode impedance of the ferrite core for high-frequency communication signals, resulting in noise removal performance. On the contrary, it will deteriorate.

Therefore, it is preferable to provide a secondary winding for canceling out the magnetic field generated in the ferrite core by the commercial current in the ferrite core of the normal mode choke coil. In this case, magnetic saturation of the ferrite core can be prevented by canceling the magnetic field generated in the ferrite core by the commercial current with the induced current of the secondary winding.
The frequency of noise affecting the PLC modem (usually 1 MHz or more) is very large compared to the frequency of commercial current (60 Hz or 50 z), and the secondary winding has a high impedance for such noise frequency, Since the influence of noise due to the provision of the secondary winding is smaller than the frequency of the commercial current, the effect of the noise block by the normal mode choke coil is maintained.

In order to achieve the second object, the present invention takes the following technical means.
That is, the present invention provides a plug that can be connected to an outlet of a power line on which a communication signal for information communication is superimposed, a plurality of pairs of branch lines branched from the plug, and a plurality of branches connected to the respective branch lines. A plurality of sockets, and the plurality of sockets are configured for a power line communication including a modem socket to which a PLC modem is connected and a device socket to which an electrical device other than the PLC modem is connected. In the relay adapter of
A common mode choke coil is connected to a branch line connecting the plug and the device socket.

In this case, since the common mode choke coil is connected to the branch line connected to the device socket, the common mode impedance of the branch line is increased by the ferrite core of the choke coil, and the power line ( A decrease in the degree of balance between the neutral line and the non-grounded line is suppressed, thereby preventing the PLC modem communication signal from leaking outside the power line.
In the present invention, a normal mode choke coil may be further connected in series with the common mode choke coil at a branch line connecting the plug and the device socket. In this case, in addition to the effect of suppressing the leakage electric field due to the increase of the common mode impedance, the effect of blocking noise from the electric equipment due to the increase of the normal mode impedance can be obtained.

As described above, according to the relay adapter of the present invention, it is possible to reduce the influence of noise and impedance loss due to the connection of electrical equipment in the home, and it is possible to manufacture it at a compact and low cost.
In addition, according to the relay adapter of the present invention, it is possible to prevent a leakage electric field by suppressing a decrease in the balance of the power line due to the connection of electrical equipment in the house.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a wiring structure of a PLC system using a relay adapter 1 according to the first embodiment of the present invention.
In the figure, an outlet 2 installed indoors is a part of the outlet of a power line 3 of a plurality of commercial power sources branched from a distribution board (not shown), and the power line 3 leading to the outlet 2 It communicates with a base unit modem (not shown) installed outdoors that can communicate with other networks. For this reason, the power line 3 has not only a function of conducting an alternating current serving as a commercial power supply but also a function as a signal transmission path for information communication.

As shown in FIG. 1, the relay adapter 1 of the present embodiment includes a single plug 6 that can be connected to the outlet 2 of the power line 3 in a housing 5 formed of a hollow box having a substantially rectangular parallelepiped shape. By attaching a modem socket 8 to which the cord plug of the PLC modem 7 is connected and a device socket 10 to which a plug protruding from a housing of an electric device 9 made of, for example, an AC adapter of a cellular phone is connected. It is configured.
The plug 6 is connected to a pair of branch lines (first branch line 11 and second branch line 12) that branch in parallel. Of these, the first branch line 11 is connected to the modem socket 8. The other second branch line 12 is connected to the device socket 10.

The length of the second branch line 12 connecting the plug 6 and the device socket 10 is longer than the length of the first branch line 11 connecting the plug 6 and the modem socket 8. In the embodiment, the second branch line 12 is made of a 1.6 mm flat cord and is set to a length of about 0.5 to 2.0 m.
According to the relay adapter 1 according to the above configuration, the second branch line 12 connected to the device socket 10 is set to a length of about 0.5 to 2.0 m, thereby connecting the electrical device 9 to the socket 10. It is intended to prevent a decrease in impedance that accompanies it.

For this reason, the attenuation of the communication signal due to the communication signal in the power line 3 being sucked into the electric device 9 side can be suppressed, and the deterioration of the communication performance of the PLC modem accompanying the connection of the electric device 9 can be prevented. it can.
Moreover, according to the relay adapter 1 of this embodiment, since it is not necessary to provide an inductor or a capacitor in the housing 5, a relay adapter with a filter function can be manufactured at low cost.

FIG. 2 shows a wiring structure of a PLC system using the relay adapter 1 according to the second embodiment of the present invention.
As shown in FIG. 2, the relay adapter 1 of the present embodiment also has a plug 5 that can be connected to the outlet 2 of the power line 3 in a housing 5 made of a hollow box having a substantially rectangular parallelepiped shape, By attaching a modem socket 8 to which the cord plug of the PLC modem 7 is connected and a device socket 10 to which a plug protruding from a housing of an electric device 9 made of, for example, an AC adapter of a cellular phone is connected. It is configured.
The plug 6 is connected to a pair of branch lines (first branch line 11 and second branch line 12) that branch in parallel. Of these, the first branch line 11 is connected to the modem socket 8. The other second branch line 12 is connected to the device socket 10.

In the relay adapter 1 of the present embodiment, the normal mode choke coil 14 is connected to the second branch line 12 that connects the plug 6 and the device socket 10. The choke coil 14 is configured by winding one wire 12a constituting the second branch wire 12 and the other wire 12b around the ring-shaped ferrite core 15 in the opposite directions by the same number of times.
According to the relay adapter 1 according to the above configuration, the normal mode choke coil 14 is connected to the second branch line 12 connected to the device socket 10, so that the normal of the branch line 12 is caused by the ferrite core 15 of the choke coil 14. Mode impedance (differential impedance) increases. For this reason, the noise which generate | occur | produces from the electric equipment 9 is blocked, and the communication performance of the PLC modem 7 can be improved.

Further, according to the relay adapter 1 of the present embodiment, it is only necessary to provide the normal mode choke coil 14 inside the housing 5, and an inductor or a capacitor is not required unlike the conventional blocking filter. The adapter can be manufactured in a compact and low cost.
FIG. 3 shows a modification of the normal mode choke coil 14 used in the relay adapter 1 of the second embodiment.
In this case, a secondary winding 16 for canceling the magnetic field generated in the ferrite core 15 by the commercial current is wound around the choke coil 14. The secondary winding 16 is further wound around the second ferrite core 17. It is wound.

According to the relay adapter 1 according to this modification, the magnetic field generated in the ferrite core 15 by the commercial current is canceled by the induced current of the secondary winding 16. For this reason, it is possible to prevent magnetic saturation from occurring in the ferrite core 15 and to effectively prevent the noise removal performance from being deteriorated.
Since the noise frequency is higher than the frequency of the commercial current, the impedance of the secondary winding 16 with respect to the noise frequency is large, and the ferrite of the normal mode choke coil 14 can be provided without providing the second core 17 as shown in FIG. The effect of the noise block by the core 15 is maintained. However, if the second core 17 is provided, the influence of the secondary winding 16 on high frequency noise can be further reduced, and the noise blocking effect by the ferrite core 15 can be more reliably maintained.

FIG. 4 shows a wiring structure of a PLC system using the relay adapter 1 according to the third embodiment of the present invention.
As shown in FIG. 4, the relay adapter 1 of the present embodiment also has a plug 5 that can be connected to the outlet 2 of the power line 3 in a housing 5 made of a hollow box having a substantially rectangular parallelepiped shape, By attaching a modem socket 8 to which the cord plug of the PLC modem 7 is connected and a device socket 10 to which a plug protruding from a housing of an electric device 9 made of, for example, an AC adapter of a cellular phone is connected. It is configured.
The plug 6 is connected to a pair of branch lines (first branch line 11 and second branch line 12) that branch in parallel. Of these, the first branch line 11 is connected to the modem socket 8. The other second branch line 12 is connected to the device socket 10.

In the relay adapter 1 of the present embodiment, the common mode choke coil 18 is connected to the second branch line 12 that connects the plug 6 and the device socket 10. The choke coil 18 is configured by winding one wire 12a and the other wire 12b constituting the second branch wire 12 around the ring-shaped ferrite core 15 in the same direction and the same number of times.
According to the relay adapter 1 according to the above configuration, the common mode choke coil 18 is connected to the second branch line 12 connected to the device socket 10, so the common of the branch line 12 is connected by the ferrite core 15 of the choke coil 18. The mode impedance increases. For this reason, a decrease in the balance of the power line (neutral line and ungrounded line) 3 due to the connection of the electric device 9 is suppressed, and the communication signal of the PLC modem 7 is prevented from leaking outside the power line 3. be able to.

Also, in the case of the relay adapter 1 according to the present embodiment, it is only necessary to provide the common mode choke coil 18 inside the housing 5, so that the relay adapter 1 with a filter function can be manufactured in a compact and low cost. .
It should be noted that the provision of the common mode choke coil 18 on the second branch line 12 of the relay adapter 1 cannot cope with normal mode noise and impedance reduction. For this reason, also in this embodiment, like the case of the first embodiment, the second branch line 12 is set to a length of about 0.5 to 2.0 m, which is much longer than usual, and the power line 3 It is preferable to suppress the attenuation of the communication signal.

  Although not shown, in the relay adapter 1 of the third embodiment shown in FIG. 4, a normal mode choke coil shown in FIG. 2 or 3 is connected to the second branch line 12 connecting the plug 6 and the device socket 10. 14 may be connected in series with the common mode choke coil 18. In this case, in addition to the effect of suppressing the leakage electric field by increasing the common mode impedance, it is possible to obtain the noise blocking effect from the electrical device 9 by increasing the normal mode impedance.

In addition, each said embodiment is an illustration and is not restrictive. The scope of the present invention is defined by the claims, and all modifications within the scope equivalent to the configurations described therein are also included in the scope of the present invention.
For example, in each of the above-described embodiments, the case where two pairs of branch lines 11 and 12 are connected to one plug 6 is illustrated, but three or more pairs of branch lines are branched to one plug 6. In this case, two or more modem sockets 8 and / or device sockets 10 are provided.

  Further, the casing 5 of the relay adapter 1 does not necessarily have to be a shape-retaining box, and may be formed of a flexible bag that can insulate the branch lines 11 and 12 and the ferrite core 15 from the outside. it can. Furthermore, the housing 5 itself of the relay adapter 1 can be omitted.

It is a wiring structure figure of the PLC system using the relay adapter which concerns on 1st embodiment. It is a wiring structure figure of the PLC system using the relay adapter which concerns on 2nd embodiment. It is a top view of the normal mode choke coil which shows the modification of the relay adapter which concerns on 2nd embodiment. It is a wiring structure figure of the PLC system using the relay adapter which concerns on 3rd embodiment. It is a wiring structure figure of the PLC system using the conventional relay adapter. It is a wiring structure figure of the PLC system using the conventional relay adapter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Relay adapter 2 Outlet 3 Power line 5 Case 6 Plug 7 PLC modem 8 Modem socket 9 Electrical equipment 10 Equipment socket 11 First branch line (branch line)
12 Second branch line (branch line)
14 Normal mode choke coil 15 Ferrite core 16 Secondary winding 17 Second ferrite core (second core)
18 Common mode choke coil

Claims (6)

A plug that can be connected to an outlet of a power line on which a communication signal for information communication is superimposed, a plurality of pairs of branch lines branched from the plug, and a plurality of sockets respectively connected to the branch lines In the relay adapter for power line communication, the plurality of sockets are composed of a modem socket to which a PLC modem is connected and a device socket to which an electrical device other than the PLC modem is connected.
By making the length of the branch line connecting the plug and the device socket longer than the length of the branch line connecting the plug and the modem socket, the impedance associated with the connection of the electrical device to the device socket is reduced. A relay adapter for power line communication, characterized in that decline is prevented. A plug that can be connected to an outlet of a power line on which a communication signal for information communication is superimposed, a plurality of pairs of branch lines branched from the plug, and a plurality of sockets respectively connected to the branch lines In the relay adapter for power line communication, the plurality of sockets are composed of a modem socket to which a PLC modem is connected and a device socket to which an electrical device other than the PLC modem is connected.
A relay adapter for power line communication, wherein a normal mode choke coil is connected to a branch line connecting the plug and the device socket.   The relay adapter for power line communication according to claim 2, wherein a secondary winding for canceling a magnetic field generated in the ferrite core by a commercial current is provided on the ferrite core of the normal mode choke coil. A plug that can be connected to an outlet of a power line on which a communication signal for information communication is superimposed, a plurality of pairs of branch lines branched from the plug, and a plurality of sockets respectively connected to the branch lines In the relay adapter for power line communication, the plurality of sockets are composed of a modem socket to which a PLC modem is connected and a device socket to which an electrical device other than the PLC modem is connected.
A relay adapter for power line communication, wherein a common mode choke coil is connected to a branch line connecting the plug and the device socket.   The relay adapter for power line communication according to claim 4, wherein a normal mode choke coil is further connected in series with the common mode choke coil to a branch line connecting the plug and the device socket.   The relay adapter according to any one of claims 1 to 5, connected to a power line outlet on which a communication signal for information communication is superimposed, a PLC modem connected to a modem socket of the adapter, and the adapter Wiring structure in power line communication consisting of electrical equipment connected to the equipment socket.

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