JP5103595B2 - High frequency injection apparatus for power line communication system - Google Patents

Description

  The present invention relates to a power line communication system, and more particularly to a high frequency injection device that injects a high frequency signal into a power line by magnetic coupling.

  When constructing a communication system using a power line drawn into a home, a means for superposing a high-frequency signal (frequency band of 1 MHz to 30 MHz) on the power line is required. As one example, a capacitive system in which capacitors 51 and 52 as shown in FIG. 6A-1 are directly connected to power lines 53 and 54 to inject a high-frequency signal from the signal line 50, or FIG. There is a ferrite method in which injection is performed using ferrite cores 55 and 56 as shown. FIG. 6A-2 and FIG. 6B-2 show the respective injection characteristics. (C) as an extreme example when the line impedance of the power line is low, and (b) when open as an extreme example when the impedance is high (in the case of (c) and (b), the power line) In the experiment, power was supplied to (a) when the power line was terminated at 90Ω. As a result, the capacitive method (FIG. 6 (A-2)) reduces the injection efficiency when the impedance of the power line is low (c), and the ferrite method (FIG. 6B-2) when the impedance of the power line is high (b). It can be seen that the injection efficiency decreases. FIG. 6 (C-1) shows a combination of both types for improving these characteristics. When both types are used together as shown in the figure, injection characteristics slightly improved as shown in FIG. 6 (C-2) can be obtained, but when the impedance is low (c), the injection characteristics are lowered in the low band of the signal band. Therefore, a more stable injection method has been demanded.

In Japan, the single-phase low-voltage distribution system (TT system: see FIG. 7) includes two power lines and three power lines, neutral lines installed on the ground. Therefore, since the high frequency signal superimposed on the power line is always superimposed on one of the neutral line and the other power line, the high frequency signal can be always received by connecting the modem to a 100 V commercial power source.
FIG. 7 is a conceptual diagram of a TT system adopted in a Japanese power distribution system. The middle point of the secondary side of the pole transformer 40 is grounded by the ground line 41 to the ground. Therefore, the voltage at both ends of the transformer 40 (between the power lines 42 and 43) is 200V, but is 100V between the transformer 40 and the neutral line 44. And the electric power is integrated by the watt-hour meter 49 in a consumer through the breaker of the electric power company which is not shown in figure, and the 3-wire power line enters into the distribution board 45, and each household appliance via each breaker 45a, 45b, 45c 46, 47, 48. Therefore, for example, if the home appliance 46 is a PC, the power line modem in the PC can communicate by transmitting and receiving a high-frequency signal superimposed on the power line 42 and the neutral line.
In addition, there are those disclosed in Patent Literature 1 and Patent Literature 2 for injecting signals with an electromagnetic inductive coupling (magnetic coupling) circuit using a ferrite core.
JP 2006-295247 A JP 2004-289458 A

However, actually, since various electric products are connected to the power line, the impedance of the power line greatly changes. In other words, since the impedance situation fluctuates due to the insertion / extraction of the outlet, the signal injection method shown in FIG. 6 and the conventional techniques disclosed in Patent Documents 1 and 2 have a signal injection efficiency due to a change in impedance. There is a problem that stable communication cannot be secured.
In view of such a problem, the present invention includes a capacitor element connected between two power lines, an injection unit that injects a high-frequency signal into each of the capacitor element and each power line, and a signal line that supplies a high-frequency signal to each injection unit. It is an object of the present invention to provide a power line communication system that suppresses a decrease in high-frequency signal injection efficiency even when the impedance of the power line fluctuates.

In order to solve this problem, the present invention provides a high frequency injection apparatus according to a power line communication system for transmitting and receiving signals by superimposing a high frequency signal on a power line, the signal line supplying the high frequency signal; A tubular power line injection section for injecting a high frequency signal flowing in the signal line into the power line, a capacitive element for connecting the power lines by terminal lines extending from both poles to bypass the high frequency signal, and a high frequency flowing in the signal line A tubular capacitive injection section for injecting a signal into the power line through a terminal line of the capacitive element, and the power line injection section is disposed in each power line so that the power line penetrates the inside thereof, and the capacitive injection Is arranged in each terminal line so that the terminal line penetrates the inside, and the signal line is used as one power line. The power line injection section and the capacity injection section disposed on one terminal line are sequentially penetrated, and the signal line is disposed on the capacity injection section disposed on the other terminal line and the other power line. A loop is formed by sequentially passing through the power line injection unit.
The power line communication system is a power line communication system that includes an injection unit on the power line on the secondary side of the transformer, and superimposes a high-frequency signal transmitted from the modem on the power line via the injection unit to exchange data between the modems. . However, since the impedance of the power line changes due to the load change, there is a problem that the transmission characteristics change due to the impedance change when the high frequency signal is injected. Therefore, in the present invention, even if the impedance changes, the power lines are connected by capacitive elements so that the transmission characteristics in each frequency band do not change and are bypassed in high frequency, and each power line and both terminal lines of the capacitive elements are respectively connected. An injection part is provided, and a high frequency signal is injected into each injection part through a signal line serially. Thereby, even if the impedance of the power line fluctuates, the transmission characteristics in each frequency band can be stabilized.

A second aspect of the present invention relates to a high frequency injection apparatus according to a power line communication system that transmits and receives signals by superimposing a high frequency signal on a power line, the signal line supplying the high frequency signal, and the high frequency signal flowing through the signal line as the power line. A tubular power line injection section for injecting into the power supply, a capacitive element for connecting the power lines to bypass the high-frequency signal, and a tubular for injecting a high-frequency signal flowing through the signal line into the power line via a terminal line of the capacitive element A capacity injection section, wherein the power line injection section is disposed on any one of the power lines so that the power line penetrates the interior thereof, and the capacity injection section is disposed so that the terminal line penetrates the interior thereof. Arranged on one of the terminal lines, and the signal lines are sequentially supplied to the power line injection section and the capacity injection section. Through was characterized by constituting the loop.
In the present invention, the injection part is inserted into one of the power line and the capacitive element terminal line. As a result, although the level of the transmission characteristic is lowered, the transmission characteristic in each frequency band can be stably obtained with respect to the impedance fluctuation. Thereby, component costs can be reduced while maintaining transmission characteristics.

According to a third aspect of the present invention, the capacity injection unit is disposed in the vicinity of the power line injection unit and on a side to which an opposing modem that performs power line communication is connected as viewed from the power line injection unit.
A signal line for transmitting a high-frequency signal can be made less susceptible to external noise if it is as short as possible. In that sense, the signal line can be made shorter if the capacity injection unit and the power line injection unit are arranged without being separated from each other. Thereby, a signal line can be shortened and S / N of a signal can be made high.

According to a fourth aspect of the present invention, when the power line injection unit and the capacity injection unit are separated by a long distance to cause noise superposition, a signal line connecting the power line injection unit and the capacity injection unit is formed by a twisted pair line. It is characterized by doing.
It is necessary to consider that the signal line magnetically coupled by the injection unit eliminates the potential difference from the ground as much as possible. However, there is a case where the capacity injection part and the power line injection part have to be arranged apart due to the convenience of wiring. In such a case, the signal line between the capacity injection unit and the power line injection unit is twisted to form a twisted pair wire. Thus, even when external noise is superimposed on the signal line, the potential difference between each other can be canceled out.

According to a fifth aspect of the present invention, the capacitance of the capacitive element is determined to be equal to or higher than a predetermined impedance at the frequency of the power line.
Since the capacitive element is connected between the power lines, if the impedance is low, extra power is consumed and the shape of the capacitive element also increases. The capacitive element is required to short-circuit between the power lines in a high-frequency manner so that the low frequency (50 Hz) does not pass as much as possible. Thereby, the high frequency can be bypassed without affecting the impedance of the power line.

According to a sixth aspect of the present invention, the power line injection unit and the capacitive injection unit are configured to magnetically couple a signal line for transmitting the high-frequency signal to the power line.
The high frequency signal superimposed on the power line appears on the surface of the power line due to the skin effect. Therefore, if the signal line is sandwiched between the surfaces of the power line, a high frequency signal can be injected by the magnetic coupling force therebetween. Thereby, a high frequency signal can be inject | poured, without performing construction of a power line.

According to the present invention, the power lines are connected by the capacitive elements and are bypassed in high frequency, and each power line and the capacitive element are respectively provided with the injection portions, and the signal lines are passed through the injection portions in series so that the high frequency signal is passed. Therefore, even if the impedance of the power line fluctuates, the transmission characteristics in each frequency band can be stabilized.
Further, the injection part is inserted into one of the power lines and the capacitive element terminal side. As a result, although the transmission level of the transmission characteristic is lowered, the transmission characteristic in each frequency band can be stably obtained with respect to the impedance fluctuation of the power line, so that the component cost can be reduced while maintaining the transmission characteristic.
Further, by disposing the capacity injection unit and the power line injection unit without separation, the signal line can be configured to be short, and the S / N of the signal can be increased.

In addition, since the signal line between the capacity injection unit and the power line injection unit is twisted and configured by a twisted pair line, even if external noise is superimposed on the signal line, the potential difference between each other can be canceled.
In addition, the capacitive element short-circuits between the power lines in a high frequency manner, and the capacitance value is determined so that the low frequency (50 Hz) does not pass as much as possible, so that the high frequency can be bypassed without affecting the impedance of the power line. it can.
Further, if the signal line is sandwiched between the surfaces of the power line, only the high-frequency signal can be injected due to the magnetic coupling force between them, so that the high-frequency signal can be injected without the construction of the power line.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. .
FIG. 1 is a configuration diagram of a high-frequency injection device according to a power communication system according to a first embodiment of the present invention. The high-frequency injection device 100 is a high-frequency injection device 100 according to a power line communication system that transmits and receives signals by superimposing a high-frequency signal from a modem 11 on power lines 1 and 6, and includes a loop-shaped signal line 8 that supplies a high-frequency signal. The high frequency signal flowing in the signal line 8 is injected into the power lines 1 and 6 and the ferrite cores (power line injection portions) 2 and 7 are connected to the connection points 9 and 10 to bypass the high frequency signal. A capacitor (capacitance element) 4 to be connected, and tubular ferrite cores (capacity injection portions) 3 and 5 for injecting a high-frequency signal flowing through the signal line 8 into the power lines 1 and 6 via the terminal lines 4a and 4b of the capacitor 4 It is prepared for.
Then, the power line 1 is passed through the ferrite core 2, the power line 6 is passed through the ferrite core 7, the terminal wire 4 a of the capacitor 4 is passed through the ferrite core 3, and the terminal wire 4 b of the capacitor 4 is passed through the ferrite core 5. Let A loop is formed so that the signal line 8 sequentially passes through the ferrite core 2 and the ferrite core 3 on the power line 1 side, and further passes through the ferrite core 5 and the ferrite core 7 on the power line 6 side. In addition, you may comprise each ferrite core so that what divided the tubular core along the axis | shaft may pinch | interpose a power wire or a terminal wire.

The ferrite cores 2 and 7 used in the power line injection section are relatively large because a magnetic flux density that does not saturate due to the current flowing in the power line is required. However, the ferrite cores 3 and 5 used in the capacity injection section include the capacitor 4. Since a flowing current is small, a small size can be used.
That is, this power line communication system includes an injection unit on the secondary power line of the transformer, and superimposes a high-frequency signal transmitted from the modem on the power line via the injection unit to exchange data between the modems. System. However, since the impedances of the power lines 1 and 6 change due to load fluctuations, there is a problem that transmission characteristics fluctuate due to impedance changes when a high frequency signal is injected (see FIG. 6). Therefore, in the present embodiment, the power lines 1 and 6 are connected by the capacitive element 4 and are bypassed in high frequency, and the ferrite cores 2, 7, 3 are respectively connected to the terminal lines 4 a and 4 b of the power lines 1 and 6 and the capacitive element 4. 5, and a high frequency signal is injected through each ferrite core through the signal line 8 in series. Thereby, even if the impedance of the power lines 1 and 6 fluctuates, the signal injection characteristics in each frequency band can be stabilized (details will be described later).

Moreover, the shorter the signal line for transmitting the high frequency signal, the less the influence of the external noise can be made. In that sense, the signal lines 8 can be made shorter if the ferrite cores (that is, the capacity injection part and the power line injection part) are arranged as far as possible from each other. Further, the signal line 8 near the modem 11 is twisted together. As a result, the signal line 8 can be shortened, and the S / N of the signal can be increased.
In addition, since the capacitive element 4 is connected between the power lines 1 and 6, if the impedance of the capacitive element is low, excess power is consumed and the withstand voltage value is increased, so that the shape of the capacitive element 4 is increased. The capacitive element 4 is required to short-circuit between the power lines 1 and 6 in a high-frequency manner so that a low frequency (50 Hz or 60 Hz) does not pass as much as possible. By taking such conditions into consideration and arranging an appropriate capacitive element, the high frequency can be bypassed without affecting the impedance of the power lines 1 and 6.
The high frequency signal superimposed on the power lines 1 and 6 appears on the surfaces of the power lines 1 and 6 due to the skin effect. Therefore, if the signal line 8 is sandwiched between the surfaces of the power lines, a high frequency signal can be injected by the magnetic coupling force therebetween. Thereby, a high frequency signal can be inject | poured, without performing construction of a power line.

FIG. 2 is a configuration diagram of a high-frequency injection device according to a power communication system according to the second embodiment of the present invention. The same components will be described with the same reference numerals as in FIG. The high-frequency injection device 110 is a high-frequency injection device 110 according to a power line communication system that transmits and receives signals by superimposing a high-frequency signal from the modem 11 on the power lines 1 and 6, and includes a loop-shaped signal line 8 that supplies a high-frequency signal. A high frequency signal by connecting a tubular ferrite core (power line injection part) 7 for injecting a high frequency signal flowing in the signal line 8 into the power line 6 (or the power line 1 is acceptable) and the power lines 1 and 6 to the connection points 9 and 10. A capacitor (capacitance element) 4 that bypasses the capacitor, and a tubular ferrite core (capacity injection portion) that injects a high-frequency signal flowing through the signal line 8 into the power line 6 via the terminal line 4b (4a in the case of the power line 1) 5.
The power line 6 is passed through the ferrite core 7, and the terminal line 4 b of the capacitor 4 is passed through the ferrite core 5. And a loop is comprised so that the signal wire | line 8 may penetrate the ferrite core 7 and the ferrite core 5 in the power line 6 side one by one. In addition, you may comprise each ferrite core so that what divided the tubular core along the axis | shaft may pinch | interpose a power wire or a terminal wire.
In other words, in the present embodiment, the ferrite cores 7 and 5 are inserted into the one power line 6 and the capacitive element terminal 4b side. As a result, although the injection level of the transmission characteristic is lowered, the transmission characteristic in each frequency band can be stably obtained with respect to power line impedance fluctuation. Thereby, component cost can be reduced.

FIG. 3 is a configuration diagram of a high-frequency injection device according to a power communication system according to the third embodiment of the present invention. The same components will be described with the same reference numerals as in FIG. In this high-frequency injection device 120, the power line injection part (ferrite cores 2 and 7) and the capacity injection part (ferrite cores 3 and 5) are spaced apart, and are between the ferrite cores 2 and 7 and the ferrite cores 3 and 5. The signal line is constituted by a twisted pair line 8a.
That is, it is necessary to consider that the signal line magnetically coupled by the injection unit eliminates the potential difference from the ground as much as possible. However, in some cases, the ferrite cores 2 and 7 and the ferrite cores 3 and 5 have to be arranged apart due to the convenience of wiring. In such a case, the signal lines between the ferrite cores 2 and 7 and the ferrite cores 3 and 5 are twisted to form a twisted pair wire 8a. Thereby, even when external noise is superimposed on the signal line 8a, the potential difference between each other can be canceled out.

  FIG. 4 is a diagram showing the injection characteristics in the configuration of this embodiment (FIG. 1). The vertical axis represents transmission characteristics (dB), and the horizontal axis represents the frequency (MHz) of the high-frequency signal. As an example, when the impedance is low (c) as an extreme example when the impedance is low, and when the impedance is open as an extreme example when the impedance is high (b) ((c) and (b) No power was supplied), and when the power line was terminated at 90Ω, the experiment was conducted with power supplied as (a). As is apparent from this figure, it can be seen that the transmission characteristics do not change over substantially all frequencies in each parameter.

  FIG. 5 is a view for explaining an embodiment incorporating the high-frequency injection device of the present invention. The same components will be described with the same reference numerals as in FIG. In this embodiment, the high frequency injection device 100 of the present invention is attached to the power lines 1 and 6 in the homes of the watt hour meters 15 and 16, respectively. In the case of a single high-frequency injection device 100, the signal line 8 is terminated when it passes through the ferrite cores 3 and 5, but in this embodiment, the signal line (twisted pair line) 11 is extended without termination. A high frequency signal is injected into the power lines 1 a and 6 a through the ferrite cores 2, 7, 3 and 5 of the high frequency injection device 100 provided in the adjacent wattmeter 16. In this figure, a signal line (twisted pair line) 12 for injecting a high-frequency signal into another power line (not shown) is shown.

It is a block diagram of the high frequency injection apparatus which concerns on the electric power communication system which concerns on the 1st Embodiment of this invention. It is a block diagram of the high frequency injection apparatus which concerns on the electric power communication system which concerns on the 2nd Embodiment of this invention. It is a block diagram of the high frequency injection apparatus which concerns on the electric power communication system which concerns on the 3rd Embodiment of this invention. It is a figure which shows the injection | pouring characteristic in the structure (FIG. 1) of this embodiment. It is a figure explaining the Example incorporating the high frequency injection apparatus of this invention. It is a block diagram of the high frequency injection apparatus which concerns on the conventional electric power communication system. It is a conceptual diagram of the TT system employ | adopted as the power distribution system of Japan.

Explanation of symbols

  1, 6 Power line, 2, 3, 5, 7 Ferrite core, 4 capacitor, 4a, 4b terminal line, 8 signal line, 8a twisted pair wire, 9, 10 conduction connection point, 11 modem, 100 high frequency injection device

Claims (6)

A high frequency injection device according to a power line communication system for transmitting and receiving signals by superimposing a high frequency signal on a power line,
A capacity for bypassing the high-frequency signal by connecting the power lines by a signal line for supplying the high-frequency signal, a tubular power line injection section for injecting the high-frequency signal flowing through the signal line into the power line, and a terminal line extending from both poles An element and a tubular capacitive injection section for injecting a high-frequency signal flowing through the signal line into the power line via a terminal line of the capacitive element,
The power line injection section is arranged in each power line so that the power line penetrates the inside thereof, and the capacity injection section is arranged in each terminal line so that the terminal line penetrates the inside thereof, and the signal line The power line injection section disposed on the power line and the capacity injection section disposed on the one terminal line are sequentially penetrated, and the signal line is further passed through the capacity injection section disposed on the other terminal line and the other power line. A high-frequency injection apparatus according to a power line communication system, wherein a loop is formed by sequentially penetrating through a power line injection unit arranged. A high frequency injection device according to a power line communication system for transmitting and receiving signals by superimposing a high frequency signal on a power line,
A signal line for supplying the high-frequency signal; a tubular power line injection section for injecting a high-frequency signal flowing through the signal line into the power line; a capacitive element for connecting the power lines to bypass the high-frequency signal; and the signal line A tubular capacitive injection section for injecting a high-frequency signal flowing into the power line through a terminal line of the capacitive element,
The power line injection part is disposed on any one of the power lines so that the power line penetrates the inside thereof, and the capacity injection part is disposed on any one of the terminal lines so that the terminal line penetrates the inside thereof. A high frequency injection apparatus according to a power line communication system, wherein a loop is formed by sequentially passing the signal line through the power line injection section and the capacity injection section.   The said capacity injection part is arrange | positioned in the vicinity of the said power line injection part, and the side to which the opposite modem which performs power line communication seeing from this power line injection part is connected. A high-frequency injection device according to a power line communication system.   When the power line injection unit and the capacity injection unit are separated by a long distance to cause noise superposition, a signal line connecting the power line injection unit and the capacity injection unit is configured by a twisted pair line. The high frequency injection apparatus which concerns on the power line communication system as described in any one of Claim 1 thru | or 3.   5. The high frequency injection apparatus according to claim 1, wherein the capacitance of the capacitive element is determined to be equal to or higher than a predetermined impedance at a frequency of the power line.   6. The power line according to claim 1, wherein the power line injection unit and the capacity injection unit are configured to magnetically couple a signal line for transmitting the high-frequency signal to the power line. A high-frequency injection device according to a communication system.

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