JP2011176676A - Switch circuit, indoor power line, and method of improving transmission characteristic of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent degradation of communication quality by suppressing variation of a transmission characteristic of a branch power line due to state change of a switch arranged in one-side wire line of the branch power line, in power line carrier communication using an indoor power line. <P>SOLUTION: A switch circuit arranged in one-side wire line of a branch power line BL comprising a pair of wire lines WL1, WL2 branching from a core power line ML to supply power to a power load LD is formed with a parallel circuit of an opening-closing switch SW for switching turning-on/off of current between two terminals, and a capacitor C1 having capacitance of 1-100 nF. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a switch circuit provided on a wire line on one side of a branch power line that branches from a main power line and supplies power to a power load, an indoor power line used as a network for power line carrier communication, and improvement of transmission characteristics thereof Regarding the method.

  In power line carrier communication, a network can be easily constructed and communicated by using an existing power line. In power line carrier communication using an indoor power distribution system power line, differential transmission is usually performed using a pair of wire lines in order to establish communication between two modem devices. In differential transmission, a pair of wire lines are driven separately by two signals with inverted phases, that is, signals with the sum of the signal outputs of both signals being zero. Differential transmission has several advantages over transmission schemes that use a single wire line. One of them is that when the wire line has ideal line characteristics, almost no radiant energy is generated. However, the actual line characteristics are never ideal, and the line impedance changes for each line pair.

  If the balance between the pair of wire lines is poor, a common mode current is generated on the communication line. If leakage radio waves due to the common mode current cannot be sufficiently suppressed, the influence on peripheral devices becomes a problem. In order to reduce the common mode current, various countermeasures such as impedance matching or attenuation of differential transmission signal power have been proposed in the modem device to be used.

Report on "Study Group on High-Speed Power Line Carrier Communications" 22, Ministry of Internal Affairs and Communications, December 2005

  In a power line of an indoor distribution system, as a factor of a decrease in the balance between a pair of wire lines, it opens and closes on one side of the branch power line that branches from the main power line and supplies power to a power load such as a lighting device or a ventilation fan In the case where a switch (one-sided switch) is provided, the line characteristics change in the on / off state.

  With reference to FIG. 1, the above-described decrease in the degree of balance will be described. In FIG. 1A, a power load LD such as a lighting device is provided at the tip of a branch power line BL branched from the main power line ML, and one wire line WL1 is cut halfway (intermediate point M). 2 shows a typical example of a branch power line circuit in which a pair of wire lines WL3 and WL4 extend from the open ends of the two and a cut-off switch SW is connected to the tip of the wire lines WL3 and WL4. Wire line WL1, wire line WL3, cut-off switch SW, wire line WL4 from core power line ML to intermediate point M, wire line WL1, intermediate line M to power load LD, power load LD, wire line A loop-shaped current path that returns to the main power line ML through the WL2 in order is formed, and energization of the current path is controlled by turning on and off the one-side switch SW. Here, the line length of the wire line WL2 is “L”, the line length of the wire line WL1 from the main power line ML to the intermediate point M is “mL” (0 <m <1), and the intermediate point M to the power load LD. The line length of the wire line WL1 is “(1-m) L”, and the line lengths of the wire lines WL3 and WL4 are “nL” (n> 0).

  When the cut-off switch SW is turned off, the cut-off switch SW becomes an open end, and the signal wave incident from the main power line ML side is reflected by the cut-off switch SW. In this case, as shown in FIG. 1B, the line length of the path A passing through the wire line WL3 among the two paths from the main power line ML to the one-sided switch SW is “(m + n) L”, The line length of the path B passing through the wire line WL4 is “(2-m + n) L”, the line length of the path B is longer, and the difference is “(2-2m) L”. The route A side does not pass through the power load LD, but the route B side passes through the power load LD. On the other hand, when the cut-off switch SW is on, the cut-off switch SW does not become an open end, so that the signal wave incident from the main power line ML is reflected by the power load LD. In this case, as shown in FIG. 1C, the line length of the path A passing through the wire line WL3 among the two paths from the main power line ML to the power load LD is “(1 + 2n) L”, whereas the wire The line length of the path B that does not pass through the line WL3 is “L”, and conversely, the line length of the path A is longer, and the difference is “2 nL”. Accordingly, the change in the line length difference appears as a difference in phase shift between the differentially transmitted signal waves, and the degree of unbalance between the pair of wire lines changes. Further, the change in the degree of unbalance depends on the line lengths of the wire lines WL1 and WL2 and the wire lines WL3 and WL4 and the position of the intermediate point M.

  In relation to the above problems, Chapter 5 and 5.1.4 “ON-OFF dependency of switch branching on frequency characteristics” of the “Study Group on High Speed Power Line Carrier Communication” (Non-Patent Document 1) In the section, it is reported as a phenomenon in which the intensity of the leakage electric field varies depending on whether the one-way switch is turned on or off. However, although the non-patent document 1 has reported that a difference occurs in the strength of the leakage electric field by turning on and off the one-way switch, what kind of line characteristic change appears and how to solve it? No method has been reported.

  Here, the problem that the line characteristics change when the one-sided switch is turned on and off is due to the provision of the one-sided switch. Therefore, the problem is solved by changing the one-sided switch to a two-way switch. However, in order to change the existing single cut switch to the double cut switch, the single cut switch is replaced with a double cut switch, and the wire line on the side where the single cut switch is not provided (in FIG. Wiring work is required to extend the line WL2) to the double cut switch. In addition, even when constructing a new indoor power line, the use of the double switch increases the cost.

  Further, there are cases where a three-way switch circuit for alternately turning on and off the power load of the lighting device or the like is provided at a plurality of locations such as both sides of the corridor and up and down the stairs. Next, referring to FIG. 2, a pair of switches in a case where a three-way switch circuit is provided on a wire line on one side of a branch power line that branches from the main power line and supplies power to a power load such as a lighting device. A change in the degree of unbalance between the wire lines will be described. For the three-way switch circuit shown below, the solution method of changing to the double switch is not practical because the three-way switch circuit needs to be configured in a double manner.

  In FIG. 2A, a power load LD such as a lighting device is provided at the tip of a branch power line BL branched from the main power line ML, and the wire line WL1 on one side is cut halfway (intermediate points M and N). The first terminal of the first three-way switch SW1 is connected to the point M, the first terminal of the second three-way switch SW2 is connected to the intermediate point N, and the second and second terminals of the first three-way switch SW1 are connected. The third terminal and the first and second terminals of the four-way switch SW3 are respectively connected, and the second and third terminals of the second three-way switch SW1 and the third and fourth terminals of the four-way switch SW3 are respectively connected. A typical example of a branch power line circuit using a three-way switch is shown. In this specification, a circuit between the intermediate points M and N including the two three-way switches SW1 and SW2 is referred to as a three-way switch circuit.

  In the three-way switch circuit shown in FIG. 2A, only one of the switches SW1 to SW3 is switched, so that conduction between the intermediate points M and N is alternately switched. Here, the three-way switches SW1 and SW2 are configured such that one is conductive while the other is non-conductive and the other is non-conductive between the first terminal and the third terminal. The four-way switch SW3 is switched between the first terminal and the third terminal, between the second terminal and the fourth terminal, and between the first terminal and the fourth terminal and between the second terminal and the third terminal. The state is switched alternately. The number of four-way switches SW3 provided in the three-way switch circuit may be 0 or 2 or more. Wire line WL1, from main power line ML to intermediate point M, three-way switch SW1, four-way switch SW3, three-way switch SW2, wire line WL1 from intermediate point N to power load LD, power load LD, A loop-like current path that returns to the main power line ML is formed via the wire line WL2 in order, and the energization of the current path is controlled by switching the switches SW1 to SW3. Here, as an example, the line length of the wire line WL1 from the main power line ML to the intermediate point M and the line length of the wire line WL1 from the intermediate point N to the power load LD are respectively “L”, and four lines from the three-way switch SW1. The line length from the switch SW3 to the three-way switch SW2 is “mL”, and the line length of the wire line WL2 is “nL”.

  In the circuit configuration illustrated in FIG. 2A, when the terminal pair on the side that is conductive in each of the switches SW1 to SW3 is continuous through the intermediate wire line, the intermediate points M and N are electrically connected. When the terminal pair that is conducted by any of the switches SW1 to SW3 is switched, the path A passing through the intermediate point M from the main power line ML is cut off from the intermediate point N at the second or third terminal of the three-way switch SW2, and the main power line A path B that passes from ML through the wire line WL2, the power load LD, and the intermediate point N is disconnected from the intermediate point M at the second or third terminal of the three-way switch SW1. Therefore, regardless of which of the switches SW1 to SW3 is switched, the open end of the branch power line BL becomes the intermediate points M and N, and the signal wave incident from the main power line ML side is reflected at the intermediate points M and N. In this case, as shown in FIG. 2B, of the two routes from the main power line ML to the open end, the line length of the route A is “(1 + m) L”, while the line length of the route B is “ (1 + m + n) L ”, the line length of the path B becomes longer, and the difference is“ nL ”. The route A side does not pass through the power load LD, but the route B side passes through the power load LD. On the other hand, when the intermediate points M and N are conducting, the intermediate point M and N is not an open end, so that the signal wave incident from the main power line ML is reflected by the power load LD. In this case, as shown in FIG. 2C, the line length of the path A passing through the switches SW1 to SW3 among the two paths from the main power line ML to the power load LD is “(2 + m) L”, The line length of the path B passing through the wire line WL2 is “nL”, and the magnitude relation between the line lengths of the path A and the path B is determined according to the magnitude relation between (2 + m) and n, and the difference is “| (2 + m -N) L | " Accordingly, the change in the line length difference appears as a difference in phase shift between the differentially transmitted signal waves, and the degree of unbalance between the pair of wire lines changes. Further, the change in the degree of unbalance depends on the wire lengths between the wire lines WL1 and WL2 and the intermediate points M and N, and the positions of the intermediate points M and N.

  As described above, when a cut-off switch or a three-way switch is provided on a wire line on one side of a branch power line that branches from the main power line and supplies power to a power load such as a lighting device, depending on the state of the switch Thus, the unbalance between the pair of wire lines constituting the branch power line changes. The change appears as a difference in line length between the pair of wire lines and a difference in phase shift determined according to the wavelength of the carrier frequency of the incident signal wave, that is, a difference in transmission characteristics of the branch power line. . The difference in the transmission characteristics is that, in power line carrier communication using an indoor power line, the electrical characteristics during communication change depending on the state of the switch provided on the branch power line, and the modem has a good balance. Under communication conditions set in the device, there is a concern that the balance of the transmission path is lowered due to a change in the state of the switch and the communication quality is deteriorated.

  The present invention has been made in view of the above problems, and its purpose is to transmit a branch power line by changing the state of a switch provided on a wire line on one side of the branch power line in power line carrier communication using an indoor power line. It is in the point which suppresses the fall of communication quality by suppressing the change of a characteristic.

  In order to achieve the above object, the present invention is a switch circuit provided on a wire line on one side of a branch power line consisting of a pair of wire lines that branch from a main power line and supply power to a power load. A switch characterized by comprising an open / close switch for switching on / off of a current between the capacitor and a capacitor connected in parallel with the open / close switch between the two terminals, wherein the capacitor has an electric capacity of 1 nF to 100 nF Provide a circuit.

  Furthermore, the present invention is a switch circuit provided in a wire line on one side of a branch power line made up of a pair of wire lines that branches from a main power line and supplies power to a power load, the first terminal and the second terminal Connected between the first terminal and the second terminal, and a three-way switch for switching on and off the current between the first terminal and the third terminal so that one is on and the other is off. A second capacitor connected between the first terminal and the third terminal, wherein the first and second capacitors have a capacitance of 1 nF to 100 nF. A switch circuit is provided.

  Furthermore, the present invention is an indoor power line used as a network for power line carrier communications, or a method for improving the transmission characteristics thereof, comprising a pair of wire lines branched from a main power line and supplying power to a power load. An indoor power line characterized in that a capacitor having an electric capacity of 1 nF or more and 100 nF or less is connected in parallel to an open / close switch that switches on / off of a current between two terminals provided on a wire line on one side of the power line. Alternatively, a method for improving the transmission characteristics is provided.

  Furthermore, the present invention is an indoor power line used as a network for power line carrier communications, or a method for improving the transmission characteristics thereof, comprising a pair of wire lines branched from a main power line and supplying power to a power load. On / off of the current between the first terminal and the second terminal and the on / off of the current between the first terminal and the third terminal provided on the wire line on one side of the power line so that one is on and the other is off. For the three-way switch to be switched, a first capacitor having an electric capacity of 1 nF to 100 nF is connected between the first terminal and the second terminal, and an electric capacity is connected between the first terminal and the third terminal. Provided is an indoor power line characterized by connecting a second capacitor of 1 nF or more and 100 nF or less, or a transmission characteristic improving method thereof.

  Further, the indoor power line or the transmission characteristic improving method thereof according to the first or second feature is characterized in that one side of the pair of wire lines from the backbone power line to the power load at a carrier frequency used for the power line carrier communication. A third feature is that a balancing element that suppresses a phase difference caused by a difference in line length between the first and second sides is inserted in series into a wire line on the other side of the branch power line.

  Further, the indoor power line of the third feature or the method for improving the transmission characteristics thereof has the same material and structure as the wire line on one side of the branch power line as the balancing element, and has the same length as the difference in the line length. The fourth feature is to use a wire line.

  Further, the indoor power line or the transmission characteristic improving method thereof according to the third feature is characterized in that an inductor element is used as the balancing element.

  Furthermore, in the indoor power line or the transmission characteristic improving method thereof according to any one of the third to fifth features, the balancing element is connected to the end of the wire line on the other side of the branch power line on the side close to the power load or It is a sixth feature that it is inserted in the vicinity of the end.

  According to the above-described switch circuit, indoor power line, or indoor power line transmission characteristic improving method, the high frequency band (2 MHz to 30 MHz) or more used for high-speed power line carrier communication such as HomePlug 1.0 specification or AV specification Since the high-frequency signal wave passes through a capacitor having an electrical capacitance of 1 nF or more and 100 nF or less provided in the open / close switch or the 3-way switch, the open / close switch or the 3-way switch does not become an open end, and reflection does not occur at the location. Therefore, the change in the transmission characteristics of the branch power line due to the change in the state of the switch provided on the wire line on one side of the branch power line is eliminated or greatly suppressed, and the communication quality is reduced due to the change in the transmission characteristic of the branch power line. Can be prevented. In addition, a capacitor having an electric capacity of 1 nF or more and 100 nF or less is provided on a wire line on one side of the branch power line in order to block the passage of the frequency band from DC to the commercial AC power supply frequency (50 Hz or 60 Hz). ON / OFF of the power supply from the power supply to the power load can be controlled in the same manner as when no capacitor is provided.

  Furthermore, according to the indoor power line of the third to sixth characteristics or the method for improving the transmission characteristics thereof, the balancing element is provided on the wire line on the side where the open / close switch of the branch power line or the three-way switch is not provided. Since the balance between the pair of wire lines from the main power line to the power load is improved, the communication quality can be improved regardless of the state of the open / close switch or the three-way switch.

A schematic diagram explaining the difference between the line length and the circuit diagram explaining the effect of the cut-off switch on the branch power line of the indoor power distribution system on the decrease in balance A schematic diagram for explaining the difference between the line length and a circuit diagram for explaining the influence of the three-way switch circuit on the branch power line of the indoor power distribution system on the decrease in balance. The circuit diagram which shows typically the typical example of the indoor power line provided with the branch power line which has the cut-off switch used as the application object of this invention The circuit diagram and principal part enlarged view which show typically the indoor power line provided with the branch power line which has the cut-off switch in 1st Embodiment of this invention The figure which shows the simulation result which verified the selection range of the electric capacity of the capacitor 4 is a circuit diagram showing three types of measurement circuits each modeling the indoor power line shown in FIG. 4, the indoor power line shown in FIG. 3, and an indoor power line that does not have a branching power line having a comparative cut-off switch. Configuration diagram of a measurement circuit for measuring the transmission characteristics of the measurement circuit shown in FIGS. Configuration diagram of a measurement circuit for measuring the common current of the measurement circuit shown in FIGS. The figure which shows the Smith chart and the attenuation | damping characteristic (S21) which show the reflection characteristic (S11) of the circuit for a measurement to which the countermeasure of 1st Embodiment is applied according to ON / OFF of a single cut-off switch. The figure which shows the Smith chart which shows the reflective characteristic (S11) of the circuit for a measurement which does not apply the countermeasure of 1st Embodiment, and attenuation | damping characteristic (S21) according to ON / OFF of a one-way switch The figure which shows the common current measurement result of the circuit for a measurement which applied the countermeasure of 1st Embodiment according to ON / OFF of a single-sided switch The figure which shows the common current measurement result of the circuit for a measurement which does not apply the countermeasure of 1st Embodiment according to ON / OFF of a cut-off switch The circuit diagram which shows typically the typical example of the indoor power line provided with the branch power line which has the three-way switch circuit which becomes the application object of this invention The circuit diagram and principal part enlarged view which show typically the indoor power line provided with the branch power line which has the three-way switch circuit in 2nd Embodiment of this invention The circuit diagram which shows typically the indoor power line provided with the branch power line which has the one-piece switch in 3rd Embodiment of this invention The circuit diagram which shows the circuit for a measurement which modeled the indoor power line shown in FIG. The figure which shows the common current measurement result of the circuit for a measurement which applied the countermeasure of 1st and 3rd embodiment according to ON / OFF of a cut-off switch The circuit diagram which shows typically the indoor power line provided with the branch power line which has the three-way switch circuit in 4th Embodiment of this invention

  Embodiments of a switch circuit, an indoor power line, and a transmission characteristic improving method for an indoor power line according to the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 3 schematically shows a typical example of the indoor power line 1 before applying the present invention, that is, to which the present invention is applied. Branch power lines BL <b> 1 to BL <b> 3 are branched from three locations of the main power line ML that is wired indoors from a power meter (not shown) via a distribution board (not shown). Outlets CT1 and CT2 are connected to the ends of the branch power lines BL1 and BL2, open when not in use, and connected to a power load when in use. A pair of wire lines constituting each branch power line BL1, BL2 is not provided with a one-way switch, a three-way switch, or the like. Accordingly, the branch power lines BL1 and BL2 have the same line length from the main power line ML of the pair of wire lines to the outlet or the power load regardless of connection / disconnection of the power load. A power load LD (for example, a lighting device or a ventilation fan) is connected to the tip of the branch power line BL3, and the wire line WL1 on one side of the pair of wire lines WL1 and WL2 constituting the branch power line BL3 is in the middle (intermediate) A pair of wire lines WL3, WL4 extend from the pair of open ends, and a one-side switch (open / close switch) SW is connected to the tip. The details of the branch power line BL3 to which the one-side switch SW is connected are the same as those described with reference to FIG. As a typical example, the outlets CT1 and CT2 are attached to the walls of different rooms, the power load LD is attached to the ceiling of a room, and the cut-off switch SW is attached to the wall of the same room as the power load LD. Assuming that As a result, if a commercially available PLC (Power Line Communication) adapter (modem device) for high-speed power line carrier communication is connected to the outlets CT1 and CT2, respectively, the outlets CT1 and CT2 (between two different rooms) can be operated at high speed. Power line carrier communication is possible. In addition, as a typical example, the main power line ML is configured with a pair of a neutral line of a commercial AC power source of a single-phase three-wire 200V and two voltage lines.

  Next, FIG. 4 shows an indoor power line 2 in which the present invention is applied to the indoor power line 1 shown in FIG. The difference between the indoor power line 1 shown in FIG. 3 and the indoor power line 2 shown in FIG. 4 is that the indoor power line 2 shown in FIG. The capacitor C1 is connected between the terminals in parallel with the switch SW. In FIG. 4B, the main part surrounded by a broken line is enlarged and displayed. Here, the switch circuit 3 in which the one-side switch SW and the capacitor C1 are connected in parallel corresponds to the switch circuit according to the present invention.

  The capacitor C1 is required to have a withstand voltage exceeding the peak voltage because the peak voltage of the AC or DC voltage supplied to the main power line ML is applied to both ends when the switch SW is opened (off). In the case of a commercial AC power supply with a single-phase three-wire 200V power supply voltage supplied to the power line ML, a withstand voltage of 250V or higher is used, and in the case of a DC power supply, for example, one having a withstand voltage of 630V or higher is used. In addition, when 2 to 30 MHz is assumed as the carrier frequency band of the high-speed power line carrier communication, the impedance of the capacitor C1 is given by 1 / 2πfc (f is the carrier frequency and c is the electric capacity of the capacitor C1). The electric capacity is preferably 1 nF or more and 100 nF or less. As a result, the signal wave of the high-speed power line carrier communication passes in the frequency band, but the impedance increases in the frequency band from DC to 60 Hz, and the supply of the power supply voltage is cut off. As a capacitor satisfying the above conditions, for example, a medium and high voltage ceramic capacitor (withstand voltage of 630 V, electric capacity of 10 nF) manufactured by Murata Manufacturing Co., Ltd. can be used.

  FIG. 5 shows a circuit simulation result verified with respect to the selection range of the capacitance of the capacitor C1. The power supply voltage supplied to the main power line ML is changed from 10 Hz to 100 MHz with an AC power supply having an amplitude of 50 V, and the electric capacity of the capacitor C1 is 6 types of 0.1 nF, 1 nF, 5 nF, 10 nF, 100 nF, and 1000 nF. Assuming the case where the parasitic capacitance of the main power line ML is 0.5 nF and the power load LD is a resistance load of 100Ω, the current flowing through the power load LD and the impedance of the capacitor C1 are calculated. FIG. 5 shows that the current increases when the frequency is 60 Hz and the capacitance of the capacitor C1 exceeds 100 nF. In addition, at 1 nF or less, the increase in impedance is significant, and a clear decrease in current is observed at 2 MHz or more. Therefore, the electric capacity of the capacitor C1 is preferably 1 nF or more and 100 nF or less, but more preferably 5 nF or more and 100 nF or less in order to suppress an increase in impedance with respect to a high frequency band of 2 to 30 MHz. Furthermore, in order to better suppress the increase in current at the commercial AC power supply frequency of 60 Hz, the upper limit of the electric capacity of the capacitor C1 is preferably set to be smaller than 100 nF. Therefore, more preferably, the electric capacity of the capacitor C1 is set in the range of, for example, 5 nF to 50 nF, and more preferably 5 nF to 20 nF. In the case where a DC power supply is supplied to the main power line ML, the electric capacity of the capacitor C1 may be 100 nF or more, but considering the versatility of the switch circuit 3, it is preferably 100 nF or less. .

  Here, when the present invention is applied to the conventional indoor power line 1 shown in FIG. 3, a method of adding a capacitor C1 in parallel to the existing cut-off switch SW, and the existing cut-off switch SW are cut into pieces. There are two methods of replacing the switch circuit 3 in which the switch SW and the capacitor C1 are connected in parallel. In any case, the effect of the present invention is the same. When there is no existing indoor power line 1 and an indoor power line 2 to which the present invention is newly applied is laid, a switch circuit 3 in which a cut-off switch SW and a capacitor C1 are connected in parallel may be used as the cut-off switch. Even in this case, the switch circuit 3 may be configured in the field by individually connecting the single-cut switch SW and the capacitor C1 in parallel.

  Next, the effect when the present invention is applied will be verified based on specific measurement data. FIGS. 6A to 6C show measurement circuits (circuits to be measured) in which the indoor power lines 1 and 2 shown in FIGS. 3 and 4 are modeled for experiments. The power line PL1 is obtained by integrating the main power line ML and the branch power line BL1 between the branch power lines BL1 and BL3, and the power line PL2 is obtained by integrating the main power line ML and the branch power line BL2 between the branch power lines BL2 and BL3. Outlets CT1 and CT2 are connected to the tip. Power lines PL1 and PL2 and branch power line BL3 are connected in parallel at branch point P, respectively. FIG. 6A corresponds to the indoor power line 2 after application of the present invention shown in FIG. 4, and the electric capacity of the capacitor C1 is 10 nF. FIG. 6B corresponds to the indoor power line 1 before application of the present invention shown in FIG. 3, and the cut-off switch SW is not provided with a capacitor. FIG. 6C shows a comparative example in the case where the cut-off switch SW and the wire lines WL3 and WL4 are not provided in the branch power line BL3. 6 (a) to 6 (c), two-core vinyl insulation manufactured by Showa Electric Cable System Co., Ltd. is connected to power lines PL1, PL2, branch power line BL3, and a pair of wire lines WL3, WL4. Using vinyl sheath cables (flat 2 mm diameter), the power lines PL1 and PL2 each have a line length of 2 m, the branch power line BL3 from the branch point P to the intermediate point M, the line length from the intermediate point M to the power load LD, and The line lengths of the wire lines WL3 and WL4 from the intermediate point M to the cut-off switch SW are each 3 m. In addition, the said cable used for the circuit for a measurement does not limit the specification etc. of the cable used for the main power line and branch power line which comprise the indoor power line 2 of this invention.

  7 and 8 show a configuration diagram of a measurement circuit for transmission characteristics between the outlets CT1 and CT2 in the respective measurement circuits of FIGS. 6 (a) to 6 (c). FIG. 7 is a measurement circuit of S parameters (S11: reflection characteristic, S21: attenuation characteristic) when the outlet CT1, CT2 is a four-terminal network, and FIG. 8 shows the common current between the outlets CT1, CT2. Each of the measurement circuits is commonly used for FIGS. 6 (a) to 6 (c). The measurement circuit shown in FIG. 7 connects the first port P1 of the network analyzer 10 and the outlet CT1 via a 100Ω-50Ω impedance conversion balun 11, and connects the second port P2 of the network analyzer 10 and the outlet CT2 to 100Ω−. It is configured to be connected via a 50Ω impedance conversion balun 12. The measurement circuit shown in FIG. 8 connects the first personal computer 13 and the outlet CT1 via the PLC adapter 14, and connects the second personal computer 15 and the outlet CT2 via the PLC adapter 16, and is in front of the outlet CT2. The current probe 17 is provided at the measurement point P, and the current probe 17 is connected to the input port P3 of the real-time spectrum analyzer 18. The first personal computer 13 and the PLC adapter 14 and the second personal computer 15 and the PLC adapter 16 are connected by an Ethernet (Ethernet is a registered trademark) cable, respectively. As the PLC adapters 14 and 16, those commercially available by the applicant based on the HomePlug AV specification were used. For data transmission between the personal computers 13 and 15, data was transmitted from the personal computer 13 to the personal computer 15 using self-made software for measuring UDP (User Datagram Protocol) throughput.

  9 and 10 show the measurement of S parameters (S11: reflection characteristics, S21: attenuation characteristics) when the cut-off switch SW of the measurement circuit shown in FIGS. 6 (a) and 6 (b) is on and off. Results are shown. FIG. 9 shows the characteristics when the present invention is applied (FIG. 6A), FIG. 10 shows the characteristics when the present invention is not applied (FIG. 6B), and each figure (a) shows the reflection characteristics. (S11) is shown, and each figure (b) shows the attenuation characteristic (S21). From FIG. 10, before application of the present invention, the reflection characteristic and the attenuation characteristic between the outlets CT1 and CT2 are greatly different due to the influence of the branch power line BL3 provided with the cut-off switch SW when the cut-off switch SW is turned on and off. I understand that On the other hand, as shown in FIG. 9, in the case of the present invention in which the capacitor C1 is provided in parallel with the cut-off switch SW, the reflection characteristics between the outlets CT1 and CT2 are turned on and off when the cut-off switch SW is turned on and off. The difference between the attenuation characteristics is greatly suppressed, and there is almost no difference between the two characteristics.

  11 and 12 show the measurement results of the common current when the cut-off switch SW of the measurement circuit shown in FIGS. 6A and 6B is on and off. In addition, in FIG.11 and FIG.12, the measurement result of the common current of the circuit for a measurement shown in FIG.6 (c) is written together as a comparative example. From FIG. 12, it can be seen that there is a large difference in the measurement result of the common current depending on the frequency range between when the cut-off switch SW is turned on and when the cut-off switch SW is turned on. On the other hand, as shown in FIG. 11, in the case of the present invention in which the capacitor C1 is provided in parallel with the cut-off switch SW, the difference in the measurement result of the common current is large when the cut-off switch SW is turned on and off. It turns out that it is suppressed. In FIG. 11 and FIG. 12, the difference in the measurement result of the common current of the measurement circuit shown in FIG. 6C is the same as the measurement of the S parameter and the common current in the high frequency band of 2 to 30 MHz. Even the measurement circuit is susceptible to the influence of the surrounding environment (noise, etc.), so the results are slightly different, but the effect of applying the present invention is clearly shown.

[Second Embodiment]
FIG. 13 schematically shows a typical example of the indoor power line 4 before applying the present invention, that is, to which the present invention is applied. Branch power lines BL <b> 1 to BL <b> 3 are branched from three locations of the main power line ML that is wired indoors from a power meter (not shown) via a distribution board (not shown). Outlets CT1 and CT2 are connected to the ends of the branch power lines BL1 and BL2, open when not in use, and connected to a power load when in use. A pair of wire lines constituting each branch power line BL1, BL2 is not provided with a one-way switch, a three-way switch, or the like. Accordingly, the branch power lines BL1 and BL2 have the same line length from the main power line ML of the pair of wire lines to the outlet or the power load regardless of connection / disconnection of the power load. A power load LD (for example, a lighting device or a ventilation fan) is connected to the tip of the branch power line BL3, and a section in the middle of the wire line WL1 on one side of the pair of wire lines WL1 and WL2 constituting the branch power line BL3. Two intermediate three-way switches SW1 and SW2 and a pair of wire lines WL3 and WL4 are provided (between the intermediate points M and N). The first terminal of the first three-way switch SW1 is connected to the intermediate point M, the first terminal of the second three-way switch SW2 is connected to the intermediate point N, and the second terminal of the first three-way switch SW1. And the second terminal of the second three-way switch SW2 are connected to both ends of the wire line WL3, respectively, and the third terminal of the first three-way switch SW1 and the third terminal of the second three-way switch SW2 are connected to the wire line WL4. Are connected to both ends. The three-way switches SW1 and SW2 are switched so that one is conductive while the other is non-conductive and the conductive non-conductive between the first terminal and the second terminal and the non-conductive between the first terminal and the third terminal. A four-way switch can be provided in the middle of the pair of wire lines WL3 and WL4 as shown in FIG. 2 (a). Suppose. When the intermediate points M and N are conductive, only one side of the pair of wire lines WL3 and WL4 is used. The details of the branch power line BL3 to which the two three-way switches SW1 and SW2 are connected are the same as those described with reference to FIG. As a typical example, the outlets CT1 and CT2 are attached to the walls of different rooms, the power load LD is attached to the ceiling of the staircase or the hallway, and the three-way switches SW1 and SW2 are located at positions separated from each other on the staircase or the hallway. Assume that it is attached to a wall. This enables high-speed power line communication between outlets CT1 and CT2 (between two different rooms) by connecting commercially available PLC adapters (modem devices) for high-speed power line communication to outlets CT1 and CT2, respectively. It becomes. In the second embodiment, in the indoor power line 4 shown in FIG. 13, the pair of wire lines of the branch power line BL3 extending from the main power line ML to the power load LD has a line length on the side passing through the wire line WL1. Assume that the wire length is longer than the wire length of the wire line WL2.

  Next, FIG. 14 shows an indoor power line 5 to which the present invention is applied to the indoor power line 4 shown in FIG. The difference between the indoor power line 4 shown in FIG. 13 and the indoor power line 5 shown in FIG. 14 is that the indoor power line 5 shown in FIG. Capacitors C2 and C3 are connected in parallel between the first and second terminals and between the first and third terminals, respectively. In FIG. 14B, the main part surrounded by a broken line is enlarged and displayed. Here, the switch circuit 6 including the three-way switch SW1, the capacitors C2 and C3 connected between the first and second terminals and between the first and third terminals corresponds to the switch circuit according to the present invention. The three-way switch to which the capacitors C2 and C3 are added may be the second three-way switch SW2 on the intermediate point N side. It is sufficient if the capacitors C2 and C3 are connected to one of the two three-way switches SW1 and SW2. This is because the intermediate points M and N with respect to the signal in the high frequency band can be obtained by connecting a capacitor between any two terminals of the three-way switches SW1 and SW2 that are open at both the intermediate points M and N. This is because is not an open end. The above is the same even if a four-way switch is added between the two three-way switches SW1 and SW2, and it is not necessary to add a capacitor to the four-way switch as in the case of the three-way switch SW1.

  Capacitors C2 and C3 have the same specifications as the capacitor C1 described in the first embodiment. Therefore, each capacitance is preferably 1 nF or more and 100 nF or less, more preferably, for example, the capacitance of the capacitors C2 and C3 is set in the range of 5 nF to 50 nF, and more preferably 5 nF to 20 nF. Good to do.

  Here, when the present invention is applied to the conventional indoor power line 4 shown in FIG. 13, a method of adding capacitors C2 and C3 to the existing three-way switch SW1, and the existing three-way switch SW1 to three There are two methods of replacing the switch circuit 6 in which the capacitors C2 and C3 are connected to the switch SW1, and the effect exhibited by the present invention is the same in any case. When there is no existing indoor power line 4 and a new indoor power line 5 to which the present invention is applied is laid, a switch circuit 6 in which capacitors C2 and C3 are connected to a three-way switch SW1 may be used as a single-cut switch. . In this case as well, the switch circuit 6 may be configured on-site by individually connecting the capacitors C2 and C3 in parallel to the three-way switch SW1.

  Since the effect when the present invention is applied is the same as that of the first embodiment, verification and explanation based on specific measurement data are omitted.

[Third Embodiment]
In the first embodiment, the capacitor C1 is connected in parallel between the two terminals of the cut-off switch SW, and the difference in the transmission characteristics of the indoor power line when the cut-off switch SW is turned on and off is realized. . However, in the branch power line provided with the cut-off switch SW, even when the cut-off switch SW is turned on, a difference occurs in the line length between the pair of wire lines from the main power line ML to the power load LD, and the balance is lowered. The possibility of this is as described with reference to FIG. Therefore, the switch circuit 3 of the present invention shown in the first embodiment is effective in suppressing the difference in the transmission characteristics of the indoor power line when the cut-off switch SW is turned on and off. Is not sufficient to suppress a decrease in the balance when the is on. In the third embodiment, measures are taken to improve the decrease in the balance.

  FIG. 15 shows an indoor power line 7 in which a measure for improving the balance is applied to the indoor power line 2 to which the present invention shown in FIG. 4 is applied. The difference between the indoor power line 2 shown in FIG. 4 and the indoor power line 7 shown in FIG. 15 is that the pair of wire lines WL3 and WL4 of the branch power line BL3 are not connected to the indoor power line 7 shown in FIG. This is the point that the balancing element 8 is connected to the open end where WL2 is cut halfway (intermediate point Q). In the third embodiment, as the balancing element 8, a cable having the same material and structure as the wire lines WL 3 and WL 4 and having the short ends of the pair of wire lines WL 5 and WL 6 having the same length is used. As a result, the pair of wire lines of the branch power line BL3 has one side constituted by the wire lines BL1, BL3, BL4 and the other side constituted by the wire lines BL2, BL5, BL6, and the respective line lengths are equal. A decrease in the balance due to the difference between the two is suppressed.

  Regardless of the position of the intermediate point Q on the wire line WL2, the line lengths of the other wire lines BL2, BL5, BL6 are the same, so the position of the intermediate point Q is near the power load LD or the wire line The end of the power load LD side of WL2 may be used. In this case, there is an advantage that the operation of connecting the balancing element 8 to the intermediate point Q can be easily performed from the ceiling or wall surface to which the power load LD is attached.

  Next, the effect when the balancing element 8 is connected to the intermediate point Q will be verified based on specific measurement data. FIG. 16 shows a measurement circuit in which the indoor power line 7 shown in FIG. 15 is modeled for an experiment. The electric capacity of the capacitor C1 is 10 nF. Since power lines PL1 and PL2 are the same as the measurement circuit shown in FIG. 6, overlapping description is omitted. FIG. 17 shows the measurement results of the common current when the cut-off switch SW of the measurement circuit shown in FIG. 16 is on and off. In FIG. 17, the measurement result of the common current of the measurement circuit shown in FIG. 6C is also shown as a comparative example.

  When the measurement result of the common current in the first embodiment shown in FIG. 11 and the measurement result of the common current in the third embodiment shown in FIG. 17 are compared, by connecting the balancing element 8 to the intermediate point Q, In both cases where the cut-off switch SW is turned on and off, the measurement result of the common current of the measurement circuit shown in FIG. 16 shows that the measurement circuit shown in FIG. It can be seen that the approximation is based on the measurement result of the common current. From this, it can be seen that the balance is improved by providing the capacitor C1 in parallel with the cut-off switch SW and further connecting the balancing element 8 to the intermediate point Q.

  In the third embodiment, the balancing element 8 is a cable having the same material and structure as that of the wire lines WL3 and WL4 and having a pair of wire lines WL5 and WL6 having the same length short-circuited. The purpose of connecting the balancing element 8 is to compensate for the phase shift caused by the difference in the line length. Therefore, an inductor element capable of causing a phase shift by being connected and also allowing direct current to flow therethrough is provided. It can also be used as the balancing element 8. By the way, since the phase shift due to the difference in line length actually changes depending on the difference in line length and the carrier frequency, in order to improve the measurement result of the common current in the field in advance, It is also preferable to use one or more of the prepared several types of inductor elements having different inductances in series or in parallel as the balancing element 8.

[Fourth Embodiment]
In the second embodiment, the capacitor C2 and the capacitor C3 are connected between the first and second terminals of the three-way switch SW1 or SW2 and between the first and third terminals, respectively, and when the intermediate points M and N are in conduction. It was possible to suppress the difference in the transmission characteristics of indoor power lines when out of traffic. However, in the branch power line provided with the three-way switches SW1 and SW2, a difference occurs in the line length between the pair of wire lines from the main power line ML to the power load LD even when the intermediate points M and N are conductive. As described with reference to FIG. 2, the degree of balance may be lowered. Therefore, the switch circuit 6 of the present invention shown in the second embodiment is effective for suppressing the difference in the transmission characteristics of the indoor power line between the intermediate points M and N during conduction and non-communication. It is not sufficient to suppress a decrease in the degree of balance during conduction between points M and N. In the fourth embodiment, measures are taken to improve the decrease in the balance.

  FIG. 18 shows an indoor power line 9 in which a measure for improving the balance is applied to the indoor power line 5 to which the present invention shown in FIG. 14 is applied. The difference between the indoor power line 5 shown in FIG. 14 and the indoor power line 9 shown in FIG. 18 is that in the indoor power line 9 shown in FIG. 18, the wire line WL2 on the side where the three-way switches SW1 and SW2 of the branch power line BL3 are not connected. The balancing element 8 is connected to the open end cut along the way (intermediate point Q). In the fourth embodiment, as the balancing element 8, a pair of wire lines WL5, WL6 having the same material and structure as the wire lines WL1, WL3, WL4 is short-circuited. The length of the pair of wire lines WL5 and WL6 is a half of the difference obtained by subtracting the line length of the wire line WL2 from the total length of the wire line WL1 and the cable length of the pair of wire lines WL3 and WL4. And Thereby, a pair of wire lines of the branch power line BL3, one side is constituted by the wire line BL1 and the wire line BL3 or BL4, the other side is constituted by the wire lines BL2, BL5, BL6, and the respective line lengths are equal. A decrease in the balance due to the difference in line length is suppressed.

  Since the effect when the balancing element 8 is connected to the intermediate point Q is the same as that of the third embodiment, verification and explanation based on specific measurement data are omitted. In the fourth embodiment, as the balancing element 8, the same material and the same structure as the wire lines WL 3 and WL 4 are used, but the tips of the pair of wire lines WL 5 and WL 6 are short-circuited. The purpose of connection is to compensate for the phase shift caused by the difference in the line length, so that an inductor element that causes a phase shift by connection and that can also carry DC current is used as the balancing element 8. It is also possible to do. By the way, since the phase shift due to the difference in line length actually changes depending on the difference in line length and the carrier frequency, in order to improve the measurement result of the common current in the field in advance, It is also preferable to use one or more of the prepared several types of inductor elements having different inductances in series or in parallel as the balancing element 8.

[Another embodiment]
In the first and third embodiments described above, when a cut-off switch SW is provided on one side of a pair of wire lines as a branch power line that branches from the main power line ML and supplies power to the power load LD (first In the second and fourth embodiments, three-way switches SW1 and SW2 are provided on one side of a pair of wire lines as branch power lines that branch from the main power line ML and supply power to the power load LD. Although assumed to be provided (second type), the branch power line that branches from the main power line ML and supplies power to the power load LD is limited to one or two branch power lines of the first or second type. Instead of this, a configuration may be adopted in which a plurality of branch power lines arbitrarily combining the first or second type of branch power lines are branched from the main power line ML. The present invention shown in the first or third embodiment is applied to the power line, the first type branch power line, and the second type branch power line. Alternatively, the present invention shown in the fourth embodiment may be applied. In addition, when there are a plurality of first or second type branch power lines, it is preferable to apply the present invention according to the above type to all the branch power lines, but for some of the branch power lines. Even if the present invention is applied, the transmission characteristics can be improved.

  In each of the above embodiments, although not clearly indicated, the one-way switch SW, the three-way switch SW1, SW2, and the like are assumed to be manual switches for manually switching on / off or conduction paths. It may be a non-manual switch such as a possible switch, a timer-type switch, or a sensor-type switch that switches according to the detection signal of the sensor.

  In the third and fourth embodiments, the line length on the wire line WL1 side is the line length passing through the wire line WL1 and the line length passing through the wire line WL2 from the main power line ML to the power load LD of the branch power line BL3. The case where the balancing element 8 is provided on the wire line WL2 side has been described on the assumption that the length is long. However, when the line length on the wire line WL2 side is long, the balancing element 8 is provided on the wire line WL1 side. Anyway.

DESCRIPTION OF SYMBOLS 1,4: Conventional indoor power line 2,5,7,9: Indoor power line which concerns on this invention 3,6: Switch circuit which concerns on this invention 8: Balancing element 10: Network analyzer 11,12: Balun for impedance conversion 13 , 15: Personal computer 14, 16: PLC adapter 17: Current probe 18: Real-time spectrum analyzer A, B: Path BL: Branch power line BL1-BL3: Branch power line C1-C3: Capacitor CT1, CT2: Outlet LD: Power load ML : Core power line M, N, Q: Intermediate point P: Branch point P1, P2: Network analyzer port P3: Real-time spectrum analyzer port PL1, PL2: Power line SW: Cut-off switch (open / close switch)
SW1, SW2: 3-way switch SW3: 4-way switch WL1-WL6: Wire line

Claims (14)

A switch circuit provided on a wire line on one side of a branch power line made up of a pair of wire lines that branch from a main power line and supply power to a power load,
An on / off switch for switching on / off of current between two terminals, and a capacitor connected in parallel with the on / off switch between the two terminals,
A switch circuit, wherein the capacitor has an electric capacitance of 1 nF to 100 nF. A switch circuit provided on a wire line on one side of a branch power line made up of a pair of wire lines that branch from a main power line and supply power to a power load,
A three-way switch for switching on / off of current between the first terminal and the second terminal and on / off of current between the first terminal and the third terminal so that one is on and the other is off; the first terminal; A first capacitor connected between the second terminals; a second capacitor connected between the first terminal and the third terminal;
A switch circuit, wherein the first and second capacitors have an electric capacitance of 1 nF to 100 nF. A method for improving the transmission characteristics of an indoor power line used as a network for power line carrier communication,
For the open / close switch that switches on and off the current between the two terminals provided on the wire line on one side of the branch power line that is branched from the main power line and supplies power to the power load, the electric capacity is A method for improving transmission characteristics, wherein capacitors of 1 nF to 100 nF are connected in parallel. A method for improving the transmission characteristics of an indoor power line used as a network for power line carrier communication,
On / off of current between the first terminal and the second terminal and the first terminal provided on a wire line on one side of a branch power line that is branched from the main power line and supplies power to the power load. And a third terminal for switching the current between the first terminal and the third terminal so that one is on and the other is off. A method of improving transmission characteristics, comprising: connecting one capacitor; and connecting a second capacitor having an electric capacity of 1 nF to 100 nF between the first terminal and the third terminal.   A balancing element that suppresses a phase difference due to a line length difference between one side and the other side of the pair of wire lines from the main power line to the power load at a carrier frequency used for the power line carrier communication, the branch power line The transmission characteristic improving method according to claim 3 or 4, wherein the transmission line is inserted in series with the other wire line.   6. The transmission characteristic improvement according to claim 5, wherein a wire line having the same material and structure as a wire line on one side of the branch power line and having the same length as the difference in the line length is used as the balancing element. Method.   6. The transmission characteristic improving method according to claim 5, wherein an inductor element is used as the balancing element.   The said balancing element is inserted in the edge part near the said power load of the wire line of the other side of the said branch power line, or the edge part vicinity, The any one of Claims 5-7 characterized by the above-mentioned. Transmission characteristics improvement method. An indoor power line used as a network for power line carrier communication,
For the open / close switch that switches on and off the current between the two terminals provided on the wire line on one side of the branch power line that is branched from the main power line and supplies power to the power load, the electric capacity is An indoor power line, wherein capacitors of 1 nF to 100 nF are connected in parallel. An indoor power line used as a network for power line carrier communication,
On / off of current between the first terminal and the second terminal and the first terminal provided on a wire line on one side of a branch power line that is branched from the main power line and supplies power to the power load. And a third terminal for switching the current between the first terminal and the third terminal so that one is on and the other is off. An indoor power line, wherein one capacitor is connected, and a second capacitor having an electric capacity of 1 nF to 100 nF is connected between the first terminal and the third terminal.   A balancing element that suppresses a phase difference due to a line length difference between one side and the other side of the pair of wire lines from the main power line to the power load at a carrier frequency used for the power line carrier communication is the branch power line The indoor power line according to claim 9 or 10, wherein the indoor power line is inserted in series in a wire line on the other side.   The wire material having the same material and structure as the wire line on one side of the branch power line and having the same length as the difference in the line length is used as the balancing element. Indoor power line.   The indoor power line according to claim 11, wherein an inductor element is used as the balancing element. 14. The balance element according to any one of claims 11 to 13, wherein the balancing element is inserted in an end portion of the wire line on the other side of the branch power line on the side close to the power load or in the vicinity of the end portion. Indoor power line as described.

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