JPH0278327A - Blocking filter for indoor power line carrier - Google Patents

Abstract

PURPOSE:To obtain a blocking filter formed to have a broad band with a few number of stages or a small constant by providing a 1st circuit connected in series with a power line and offering a high impedance to a carrier frequency, dividing the 1st circuit into two and providing an opposite phase injection circuit to the midpoint. CONSTITUTION:The 1st circuit connecting in series with the power line, offering a low impedance at a commercial power frequency (50/60Hz) and a high impedance at a carrier frequency (100-450kHz) is divided into two (captions 1, 3) and the opposite phase injection circuit 2 is provided on the midpoint. The opposite phase injection circuit 2 consists mainly of a differential amplifier type power amplifier and a coupling circuit and inverts the phase of a carrier signal injected from a live line and injects the resulting signal to the original live line. Thus, the carrier signal leaked from the circuit 3 being the 1st circuit is almost cancelled by the output signal of the opposite phase injection circuit 2 at the power live line where the opposite phase injection circuit 2 exists and then the carrier signal leaked to the power supply side via the circuit 1 is attenuated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a blocking filter for an indoor power line carrier system that superimposes a carrier signal on an indoor power line to monitor and control load equipment and also performs telephone calls.

[Conventional technology]

The blocking filter for such a system is:
Utility Model Publication No. 56-68351 and Japanese Patent Application Publication No. 61-212927
Examples include the number. Its basic configuration was inserted and connected in series to the power line. It has a first circuit that has a low impedance with respect to the commercial power frequency and a high impedance with respect to the carrier wave frequency, and is connected between the power lines on the commercial power source side with respect to the connection position of the first circuit. It has a second circuit that has high impedance with respect to the commercial power supply frequency and low impedance with respect to the carrier wave frequency.

Specifically, the first and second circuits constitute a band eliminator filter or a low-pass filter.

Further, when the power line is a single-phase three-wire power line, a third circuit is provided for transmitting a carrier wave between two power lines that are live lines on the load side. Specifically, this third circuit is a series shared circuit, a circuit using only a capacitor, or a circuit using a transformer with one end connected to a neutral line. The above configuration prevents the carrier signal from leaking from the indoor side to the outside (power supply side) of the blocking filter. In addition, the third
The circuit expands the communication range by transmitting the carrier signal from one side to the other, and is called a different phase open signal transmission means.

[Problem to be solved by the invention]

However, when trying to apply the above-mentioned conventional technology to spread spectrum communication, that is, when trying to widen the band, the number of stages of the band elimination filter increases, or the component constants of the low-pass filter become too large (one size or less). Issues were raised in terms of cost.

An object of the present invention is to provide a blocking filter that has a wide band with a small number of stages or small constants.

[Means to solve the problem]

In order to achieve the above object, the present invention connects a power line in series. A first circuit ya1'2 having a low impedance with respect to the commercial power frequency and a high impedance with respect to the carrier wave frequency is divided into two parts, and an anti-phase injection circuit is provided at an intermediate position.

[Effect]

The first circuit divided into two circuits works so that the impedance of the power line changes little when viewed from the reverse phase injection circuit installed in the middle. Since the signal is reversed in phase and injected into the original live wire to cancel the original carrier wave signal, it has a leakage prevention function to the power supply side.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a block diagram showing a configuration example of a blocking filter to which the present invention is applied, in which the traveling direction of power from a commercial power source is indicated by a hot solid line arrow, and the leakage direction of a carrier wave signal is indicated by a broken line arrow.

In the figure, 1 is inserted and connected in series to the power line.

It has low impedance with respect to the commercial power frequency (50fiz / 60Hz) and the carrier wave frequency (IQOKk
~450KHz) with high impedance.
This is the circuit.

Further, 3 is a circuit having the same configuration as 1, and 2 is an anti-phase injection circuit provided between circuit 1 and circuit 2. and,
4 is a third circuit for transmitting a carrier wave signal between two live power lines on the load side of a single-phase three-wire power line, and is a different-phase open signal transmission circuit.

Here, the anti-phase injection circuit 2 mainly consists of a differential amplification type power amplifier and a coupling circuit, and injects the carrier wave signal extracted from the live line into almost the opposite phase to the original live line. Therefore, in the live line of the power line in the part where the anti-phase injection circuit 2 is located, the carrier wave signal leaked from the circuit 3, which is the first circuit, is almost canceled out by the output signal of the anti-phase injection circuit 2.

As a result, the carrier wave signal leaking to the power supply side via the first circuit, circuit 1, is attenuated to such an extent that it does not pose a problem.

Next, a specific example of the configuration shown in FIG. 1 will be described with reference to FIGS. 2 and 3. In FIG. 2, the same parts as in FIG. 1 are designated by the same numbers. The first circuit 1, 3 has a capacitance C1
It consists of a parallel resonant circuit with an inductance L and an inductance L. 7 to 12 are connected to the power line.

Terminals 7 to 9 are connected to the power supply side.

Further, terminals 10 to 12 are connected to the load (indoor) side.

Terminal 8 is connected to a neutral line (ground) on the power supply side, and is also directly connected to terminal 11. Terminals 7 and IQ are each connected to one live wire.

The parallel resonant circuit of circuit 1 and the parallel resonant circuit of circuit 3 are connected by a line connected in series. Terminals 9 and 12 are each connected to the other active +ij! In addition to being IC-connected, they are also connected via two parallel resonant circuits χ. 5 is a varistor connected between terminals 7 and 8; similarly, 6 is a varistor connected between terminals 8 and 9, which absorbs surges from the power supply side. Assuming that the different phase open signal transmission circuit 4 has its primary side connected between terminals 10 and 11, its secondary side is connected between terminals 11 and 12, and is connected to a pulse transformer 13 with a turns ratio of 1:10. Consists of a coupling capacitor and its discharge resistor.

The pulse transformer 13 has both the primary side and the secondary side connected to terminal 1.
1, and the other terminal is connected to terminal 10 or 12 through a parallel circuit of a coupling capacitor and a discharge resistor, respectively.
It is connected to. By the way, as examples of set values, the inductance L3 of the pulse transformer 13 is 15 μH, and the capacitance C6 of the coupling capacitor is 0.
The resistance value Rd of the discharge resistor is IMΩ.

Now, the anti-phase injection circuit 2 is connected between the parallel resonant circuit, which is the first circuit, and the terminal 8 (or terminal 11). In this embodiment, since the power line is a three-wire system, there are two types of circuits: one is an anti-phase injection circuit centered on the differential amplification type power amplifier 14'Y, and the other is an anti-phase injection circuit centered on the same (power amplifier 15').
It is systematic. Since both have the same configuration, only the power amplifier 14 will be described here. Note that the negative feedback circuit 16 of the differential amplification type power amplifier 14 (15) is shown in FIG. 3, and will be explained together with it. The non-inverting input section of the differential amplification type power amplifier 14 is connected to the terminal 8, and is also connected to the inverting input section via a series circuit of a volume Rv and a capacitor (capacitance C4).

This series circuit of Rv and C4 is a phase compensation circuit of the power amplifier 14, and is set appropriately at 4°.On the other hand, the inverting input part of the power amplifier 14 is an inductor.

(L2) and capacitor (C2) through a series resonant circuit.

and is connected to the live wire midway between lines 1 and 3.

It is connected to the output section via the negative feedback circuit 16. and,
The output section of the power amplifier 14 is connected to a parallel resonant circuit of a capacitor (C1) and an inductor (Ll) through a capacitor (C3) Yf. The parallel resonant circuit (C1, Ll) in this anti-phase injection circuit 2 is connected to the live wire between circuits 1 and 3, and its setting value is the same as the parallel resonant circuit in the first circuit 1 or circuit 3. It is the same as a resonant circuit. Next, as shown in FIG. 3, the negative feedback circuit 16 connects in series a series resonant circuit of an inductor with an inductance of L2 and a capacitor with a capacitance of C2, and a parallel resonant circuit of an inductor with an inductance of 5 and a capacitor with a capacitance of 2C2. A resistor having a resistance value Rf is connected in parallel to the capacitor C2. Here, to give an example of component constants, capacitance C1 is 0.
033μF and inductance LIY15μF.

Inductance L2 is 1.6μH, capacitance c2
and 03 are 0.33 μF, resistance Rf is IKΩ, and capacitance C4 is about 2.2 μF.

With this configuration, carrier wave voltage vo is generated between terminals 10 and 11, and voltage v is now generated on the live line between circuits 1 and 3.
If l occurs, the voltage -Vo will occur at the output I of the power amplifier 14 after a slight delay, and the voltage of the live wire v
1 to return the carrier frequency to voltage O. This result 1
The carrier wave signal leaking from the circuit 1 to the terminal 7 side is significantly attenuated.

〔Effect of the invention〕

As explained above, according to the present invention, the carrier wave frequency (100Kk to 450KHz) inserted and connected in series to the power line
A first circuit that has a high impedance is provided, and this first circuit is divided into two, and an anti-phase injection circuit is provided in the middle, so that the carrier signal leaking from the first circuit is injected into an anti-phase injection circuit. It is canceled out by the output signal of the circuit and the power supply side (
Since the structure required to obtain this effect is relatively simple, problems in terms of size and cost are improved.

Note that the present invention is effective even if amorphous cores are used as the inductors of one circuit 1 and 3, and the power for the power amplifiers 14 and 15 of the reverse phase injection circuit may be supplied from the terminals 7 to 9.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. 2 is a circuit diagram showing a specific configuration of FIG. 1, and FIG. 3 is a circuit diagram showing a specific configuration of the negative feedback circuit 16 of the differential amplification type power amplifier of FIG. 2...Negative phase injection circuit, 14, 15...Differential amplification type power amplifier. 16... Negative feedback circuit, 4... Different phase open signal transmission circuit, 1.3... First circuit.

Claims (1)

[Claims] 1. Two first circuits that have a high impedance with respect to the carrier frequency, which are inserted and connected in series to the power line, and a carrier wave that is installed at an intermediate position between these two first circuits and extracted from the live wire of the power line. A blocking filter for an indoor power line carrier system, comprising a reverse phase injection circuit for injecting a signal into the live line with a reverse phase signal.