JP6132608B2 - Power line carrier communication equipment - Google Patents

Description

  The present invention relates to a power line carrier communication apparatus that carries power and information signals using a power line.

Conventionally, a low-frequency PLC (Power Line Communication) system called TWACS _R has been put into practical use as a network technology using a power line in electricity, gas and water customers. “TWACS _R ” is a technology that realizes bidirectional communication by superimposing an information signal on an electrical signal. The TWACS _R is provided with a power line carrier communication device as shown in FIG.

  In this power line carrier communication apparatus, a power plant Vs that generates AC power is connected to power lines PL1 and PL2 via a system impedance Ls, and a reactor Lo, a resistor R1, and a switch SW are connected in series at both ends of the power lines PL1 and PL2. A signal generator 1 comprising a circuit is connected. The power plant Vs supplies an AC voltage V as shown in FIG. 8B to the terminals T1 and T2 via the system impedance Ls.

  At the same time, the switch SW is turned on for a time from time (t0−Δt) before and after the zero cross point (time t0) of the AC voltage V of the power plant Vs to time (t0 + Δt), for example, about 1.5 ms to 3 ms. .

  For this reason, a parabolic current as shown in FIG. 8C flows through the signal generator 1 including a series circuit of the reactor Lo, the resistor R1, and the switch SW. Information signals “0” and “1” are output depending on the presence or absence of the parabolic current. That is, the AC signal from the power plant Vs and the information signal from the signal generator 1 are obtained at the terminals T1 and T2.

  Note that Patent Documents 1 to 4 are known as conventional related technologies of the reactor.

Japanese Utility Model Publication No. 1-4423 JP 2002-57046 A JP 7-183134 A JP-A-11-340064 US Patent No. 4400688 U.S. Pat. No. 4,218,655 US Pat. No. 4,595,520 US Pat. No. 5,486,805 US Patent 5933072

However, when the switch SW is turned on / off, the system voltage between the terminals T1 and T2 is distorted in the form of differentiating the parabolic current shown in FIG. These current and voltage waveforms contain many high frequency components. This high frequency component may adversely affect devices connected to the same power line.
The subject of this invention is providing the power line carrier communication apparatus which can reduce the high frequency component which generate | occur | produces with an information signal.

In order to solve the above problems, a power line carrier communication device according to the present invention has a first power line and a second power line, and carries a power via a transformer and a system impedance of the power line. And a series circuit in which a reactor unit and a switch unit are connected in series, and both ends of the series circuit are connected to the first power line of the power carrier unit and the power supply unit. A signal generator that is connected to the second power line and superimposes an information signal on the power carrier unit by turning on and off the switch unit, and the reactor unit has an inductance value that increases as current flowing through the reactor unit decreases. It is characterized by that.

  According to the present invention, since the inductance value of the reactor portion increases as the current flowing through the reactor portion decreases, the current waveform rises and falls smoothly. Therefore, it is possible to provide a power line carrier communication device that can reduce high-frequency components generated by information signals.

1 is a basic configuration diagram of a power line carrier communication device according to the present invention. It is a figure which shows the power line carrier communication apparatus which concerns on Example 1 of this invention. It is a figure which shows the power line carrier communication apparatus which concerns on Example 2 of this invention. It is a structural example of the modification of the power line carrier communication apparatus which concerns on Example 2 of this invention. It is a figure which shows the power line carrier communication apparatus which concerns on Example 3 of this invention. It is a figure which shows the power line carrier communication apparatus which concerns on Example 4 of this invention. It is a block diagram which shows the automatic meter-reading system to which the power line carrier communication apparatus of this invention is applied. It is a block diagram of the conventional power line carrier communication apparatus.

  Hereinafter, embodiments of the power line carrier communication apparatus of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a basic configuration diagram of a power line carrier communication apparatus according to the present invention. In FIG. 1A, the power plant (the power supply unit of the present invention) Vs supplies AC power to the power transfer units PL1 and PL2 via the transformer and the power line system impedance Ls.

  The signal generator 1a has a series circuit in which a variable reactor Lx (reactor unit of the present invention) and a switch SW are connected in series, and both ends of the series circuit are connected to both ends of the power transfer units PL1 and PL2, An information signal is superimposed on the power carriers PL1 and PL2 by turning on and off the switch SW (the switch unit of the present invention).

  The variable reactor Lx has an inductance value that increases as the current flowing through the reactor Lx decreases. FIG. 1B is a diagram illustrating a waveform of a current flowing through the variable reactor Lx. The variable reactor Lx increases the inductance value when the current is small, and decreases the inductance value when the current is large. Therefore, in FIG. 1B, the current waveform rises and falls as shown by the solid line. The waveform shown by the dotted line is a conventional waveform.

  Therefore, it is possible to provide a power line carrier communication device that can reduce high-frequency components generated by information signals.

  Next, specific examples of the power line carrier communication device will be described.

  FIG. 2 is a diagram illustrating the power line carrier communication apparatus according to the first embodiment of the present invention. In FIG. 2A, four saturable reactors La to Ld (reactor portions of the present invention) are connected in series with the core being saturated with an electric current of a predetermined value or more and the inductance value abruptly reduced. The switch is connected in series to the switch SW. Each of the four saturable reactors La to Ld is magnetically saturated with different current values.

  As shown in FIG. 2B, the saturable reactor La is magnetically saturated with the current i1, and the inductance value decreases rapidly. The saturable reactor Lb is magnetically saturated with a current i2 larger than the current i1, and the inductance value decreases rapidly. The saturable reactor Lc is magnetically saturated with a current i3 larger than the current i2, and the inductance value decreases rapidly. The saturable reactor Ld is not magnetically saturated.

That is, by connecting the four saturable reactors La to Ld in series, as shown in FIG. 2B, the inductance of the entire series circuit gradually decreases as the current increases.
In other words, since the inductance value increases as the current flowing through the four saturable reactors La to Ld decreases, the current waveform becomes smooth at the rise and fall of the current waveform as shown in FIG. . Therefore, high frequency components generated by the information signal can be reduced.

  FIG. 3 is a diagram illustrating the power line carrier communication apparatus according to the second embodiment of the present invention. In the power line carrier communication apparatus according to the second embodiment, the variable reactor Le (reactor portion of the present invention) shown in FIG. 3 (a) is made of a magnetic material such as ferrite constituting the magnetic closed circuit shown in FIG. 3 (b). A core 10 and a coil 12 wound around the core 10 are provided. In the core 10, vertically symmetrical gaps 13 a 1 and 13 a 2, vertically symmetrical gaps 13 b 1 and 13 b 2, and vertically symmetrical gaps 13 c 1 and 13 c 2 are formed in order at a plurality of locations P 1, P 2 and P 3. The vertical size of the gaps 13c1 and 13c2 is the smallest, the vertical size of the gaps 13b1 and 13b2 is larger than the vertical size of the gaps 13c1 and 13c2, and the vertical size of the gaps 13a1 and 13a2 is larger than the vertical size of the gaps 13b1 and 13b2. large.

  The pillar portion 14a is a core excluding the gap 13a1 and the gap 13a2 from the core 10 at the location P1. The pillar part 14b is a core which remove | excludes the gap 13b1 and the gap 13b2 from the core 10 in the location P2. The column portion 14c is a core that excludes the gap 13c1 and the gap 13c2 from the core 10 at the place P3.

  The pillar portions 14a, 14b, and 14c are magnetically saturated in the order of the pillar portions 14a, 14b, and 14c because the core cross-sectional areas increase in order. As shown in FIGS. 3B and 3C, the column portion 14a formed between the gaps 13a1 and 13a2 is magnetically saturated with the current i1, and the inductance value decreases rapidly. The column portion 14b formed between the gaps 13b1 and 13b2 is magnetically saturated with a current i2 larger than the current i1, and the inductance value is rapidly reduced. The column portion 14c formed between the gaps 13c1 and 13c2 is magnetically saturated with a current i3 larger than the current i2, and the inductance value decreases rapidly.

  In other words, by providing the column portions 14a, 14b, and 14c, as shown in FIG. 3C, the inductance gradually decreases as the current increases. In other words, since the inductance value increases as the flowing current decreases, the current waveform becomes smooth at the rise and fall of the current waveform as shown in FIG. Therefore, high frequency components generated by the information signal can be reduced.

  FIG. 4 is a structural example of a modified example of the power line carrier communication apparatus according to the second embodiment of the present invention. The modification shown in FIG. 4 is characterized in that holes 15a, 15b, and 15c are provided in place of the gaps 13a1 and 13a2, the gaps 13b1 and 13b2, and the gaps 13c1 and 13c2 shown in FIG.

  The pillar portions 16a1 and 16a2 are cores excluding the hole portion 15a from the core 10 at the location P1. The pillar portions 16b1 and 16b2 are cores excluding the hole portion 15b from the core 10 at the location P2. The pillars 16c1 and 16c2 are cores excluding the hole 15c from the core 10 at the place P3.

  The vertical sizes of the holes 15a, 15b, and 15c increase in the order of the hole 15c, the hole 15b, and the hole 15a. For this reason, since the core cross-sectional area becomes smaller in the order of the column portions 16c1 and 16c2, the column portions 16b1 and 16b2, and the column portions 16a1 and 16a2, the inductance value changes as shown in FIG. Therefore, also in the modification, the same effect as the effect of the power line carrier communication apparatus according to the second embodiment can be obtained.

  FIG. 5 is a diagram illustrating the power line carrier communication apparatus according to the third embodiment of the present invention. As shown in FIG. 5A, the power line carrier communication apparatus according to the third embodiment includes a core 10 and a coil 12 as a reactor portion, and a wedge portion in which a core is cut out in a wedge shape in a part of the core 10. 17a and 17b are provided.

  The wedge part 17 a and the wedge part 17 b are provided symmetrically with respect to the core 10. The wedge portions 17a and 17b (the core cross-sectional area changing portion of the present invention) continuously change in cross-sectional area.

  As shown in FIG. 5 (b), magnetic saturation region portions 18, 19, and 20 are formed in the tip region of the wedge portions 17 a and 17 b along the longitudinal direction of the core 10, and the magnetic saturation region portion 18, The core cross-sectional area increases in the order of the magnetic saturation region 19 and the magnetic saturation region 20.

  For this reason, the magnetic saturation region 18 is magnetically saturated with the current i1, and the inductance value decreases rapidly. The magnetic saturation region 19 is magnetically saturated with a current i2 that is larger than the current i1, and the inductance value decreases rapidly. The magnetic saturation region 20 is magnetically saturated with a current i3 that is larger than the current i2, and the inductance value decreases rapidly.

  That is, when the current is increased, the magnetic saturation region is expanded, which is equivalent to gradually increasing the gap. Therefore, as shown in FIG. 5C, the inductance gradually decreases as the current increases. In other words, since the inductance value increases as the current decreases, the current waveform becomes smooth at the rise and fall of the current waveform as shown in FIG. Therefore, high frequency components generated by the information signal can be reduced.

  FIG. 6 is a diagram illustrating the power line carrier communication apparatus according to the fourth embodiment of the present invention. In the power line carrier communication apparatus according to the fourth embodiment, as shown in FIG. 6A, a series circuit of a reactor L1 and a switch SW1, a series circuit of a reactor L2 and a switch SW2, a reactor L3 and a switch SW3, And the series circuit of the reactor L4 and the switch SW4 are connected in parallel to form a parallel circuit. This parallel circuit is connected to both ends of the power transfer units PL1 and PL2.

  Reactors L1 to L4 constitute the reactor part of the present invention, and switches SW1 to SW4 constitute the switch part of the present invention.

  FIG. 6B shows the voltage before and after the zero crossing point at the power plant Vs. Before and after the zero cross point, the switches SW1 to SW4 are turned on. As shown in FIG. 6C, the switch SW1 is turned on at time t1, the switch SW2 is turned on at time t2, the switch SW3 is turned on at time t3, and the switch SW4 is turned on at time t4.

  That is, when the switches SW1, SW2, SW3, and SW4 are turned on in the order, the reactors L1, L2, L3, and L4 are connected in parallel in order, so that the overall inductance is as shown in FIG. 6 (d). , Get smaller in order. For this reason, as shown in FIG.6 (e), an electric current increases gradually.

  Then, after exceeding the peak value of the current, the switch SW4 is turned off at time t5, the switch SW3 is turned off at time t6, the switch SW2 is turned off at time t7, and the switch SW1 is turned off at time t8.

  That is, by turning off the switches SW4, SW3, SW2, and SW1 in this order, the reactors L4, L3, L2, and L1 are removed in order, so that the overall inductance is as shown in FIG. 6 (d). Become bigger. For this reason, as shown in FIG.6 (e), an electric current reduces gradually. Therefore, the current waveform becomes smooth at the rise and fall of the current waveform. Therefore, high frequency components generated by the information signal can be reduced.

  For example, as illustrated in FIG. 7, the power line carrier communication apparatus according to the first to fourth embodiments described above performs automatic meter reading of measurement data by bidirectional communication between the power meter M and the high voltage system on the upper side of the transformer T. Applicable to automatic meter reading system.

  The power plant Vs is connected to a power meter M via a system impedance Ls (including a substation transformer), a power line, and a transformer T. The power line carrier communication device is provided on the high voltage system side (system impedance Ls, reactor Lo1, switch SW1, current transformer CT) and the power meter side (power meter M, reactor Lo2, switch SW2, voltmeter V). . The current transformer CT detects a current generated by turning on / off the switch SW2 as an information signal. The voltmeter V detects a voltage distortion generated by turning on / off the switch SW1 as an information signal.

Vs Power plant PL1, PL2 Power transfer unit Lo, Lo1, Lo2, L3, L4 Reactor Lx, Le Variable reactor La, Lb, Lc, Ld Saturable reactor Ls System impedance SW, SW1, SW2, SW3, SW4 Switch R1 Resistance T Transformer T1, T2 Terminal M Power meter 1, 1a Signal generator 10 Core 11, 13a1, 13a2, 13b1, 13b2, 13c1, 13c2 Gap 12 Coil 14a, 14b, 14c, 16a1, 16a2, 16b1, 16b2, 16c1, 16c2 Column Portions 15a, 15b, 15c Holes 17a, 17b Wedges 18, 19, 20 Magnetic saturation region

Claims (5)

A power carrier having a first power line and a second power line, and carrying the power via the transformer and the system impedance of the power line;
A power supply unit for supplying power via the power transfer unit;
A reactor unit and a switch unit have a series circuit connected in series, and both ends of the series circuit are connected to the first power line and the second power line of the power transfer unit, and the power is turned on and off by the switch unit. A power line carrier communication device comprising: a signal generator for superimposing an information signal on a carrier, wherein the reactor portion has an inductance value that increases as a current flowing through the reactor portion decreases.   The power line carrier communication apparatus according to claim 1, wherein the reactor unit includes a plurality of saturable reactors connected in series, and each of the saturable reactors is magnetically saturated with different current values. The reactor section includes a core made of a magnetic material that forms a magnetic closed circuit,
A coil wound around the core,
2. The core is formed with gaps or holes of different sizes at a plurality of locations, and the pillars of the core excluding the gap or the holes from the core are magnetically saturated at each location. Power line carrier communication device. The reactor section includes a core made of a magnetic material that forms a magnetic closed circuit,
A coil wound around the core,
The core is formed with a core cross-sectional area changing portion having a continuously changing core cross-sectional area, and is magnetically saturated in order from the smallest cross-sectional area portion of the core cross-sectional area changing portion. Power line carrier communication device. The reactor part is composed of a plurality of reactors,
The switch unit includes a plurality of switches provided in one-to-one correspondence with the plurality of reactors, and the reactor and the switches are connected in series,
The power line carrier communication device according to claim 1, wherein the plurality of switches are turned on in order and then turned off in a reverse order to the turn-on order.

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