JPH0465908A - Block filter for power line carrier - Google Patents

Abstract

PURPOSE:To realize a block filter suppressing malfunction due to an external signal with excellent installation performance by selecting an impedance at a signal frequency of 1st-4th impedance elements to have a specific condition. CONSTITUTION:First and second impedance elements 6, 7 having resonance impedance Z1, Z2 respectively at a signal frequency are inserted in series with a couple of power lines respectively, a 3rd impedance element 8 having a resonance impedance Z3 is connected from a signal input side of the impedance Z1 toward a signal output of the impedance Z2, a 4th impedance element 9 having a resonance impedance Z4 is connected from a signal input side of the impedance Z1 toward a signal output of the impedance Z2, and a condition of Z1:Z3=Z4:Z2 is satisfied by adjusting the resistance of resistors R3, R4 to realize the block filter with small size, installation work performance and excellent installation scene.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a block filter used in a power line transport system using power lines.

(Prior Art) There has conventionally been a power line transport system that transports information using a power line, and a block filter is used in this system.

FIG. 2 shows the configuration of a conventional block filter 1 for power line transport. 2 and 2'' are a pair of power lines, one of which is a series impedance element z (1 ) is connected between the signal output terminals 3 and 3' of the power lines 2 and 2', and another impedance element Z (2) that acts as a low impedance for the signal frequency and a high impedance for the power supply frequency is connected. It's nine months old,
A so-called inverse filter circuit was constructed, and the signal attenuation ratio was expressed by Z (2)/(Z (1) + Z (2)). In addition, impedance element z(1)
is a coil, or an LC parallel resonant circuit composed of a coil and a capacitor, and an impedance element z (2
) uses a coil or an LC series resonant circuit composed of a coil and a capacitor.

(Problem to be Solved by the Invention) However, in the circuit configuration as described above, in order to obtain a predetermined signal attenuation ratio, the impedance value at the signal frequency of impedance element Z(1) is made as large as possible, and the impedance value of impedance element Z(2) is made as large as possible at the signal frequency. ), it is necessary to make the impedance value of the impedance element z( ) as small as possible.
1), parts such as coils and capacitors that make up z(2) inevitably become larger, and therefore the shape of the block filter becomes extremely large, resulting in problems such as ease of construction and poor appearance when installed indoors. there were.

For example, an impedance element Z inserted in series in a power line
In order to increase the impedance value at the signal frequency in (1), it is necessary to increase the inductance of the coil as much as possible and to suppress current saturation with respect to low frequency load current, so it is necessary to increase the number of turns of the coil, or I needed to make the core bigger. Furthermore, in order to lower the impedance value at the signal frequency of the impedance element z(2) connected between the power lines, it is necessary to increase the capacitance of the capacitor as much as possible, or to use a winding coil with a large diameter to reduce loss. there were. Furthermore, since signal attenuation cannot be obtained for input signals from the opposite direction due to the circuit configuration, there is a risk that the system may malfunction due to input signals from the signal output terminal in the opposite direction.

The present invention eliminates the above-mentioned conventional problems and creates a circuit in which the attenuation characteristic is determined not by the impedance of each impedance element itself but by the impedance ratio of each element, so that each impedance element can be made smaller and the signal By making the circuit configuration as seen from the input side and the signal output side exactly the same symmetrical structure, signal attenuation can be obtained for signals from both input and output sides, and it has excellent workability.
The object of the present invention is to provide a power line carrier block filter that can suppress malfunctions caused by external signals.

(Means for Solving the Problems) The present invention achieves the above-mentioned object by connecting first and second power lines in series to a pair of power lines, respectively. A second impedance element is connected, and a third impedance element is connected from the signal input side of the first impedance element to the signal output side of the second impedance element, and the signal of the first impedance element is connected. 2. A fourth impedance element is connected from the output side to the signal input side of the second impedance element, and the impedance values Z0 to z at the signal frequency of each impedance element are determined. : 2. =2. :Z2
Achieve it by configuring it to satisfy the relationship.

(Function) According to the present invention, 1. Second. The impedance values at the signal frequency of each of the third and fourth impedance elements are Zl, Z, respectively.

When Z and Z, the signal attenuation ratio of the block filter is expressed by the coefficient of (Z4/Zt-Z, /Z3), and only needs to satisfy the condition Z, /Z2 = Z□/Z3. Signal attenuation performance will be obtained. That is, as long as the above impedance ratio is satisfied, the impedance value of each impedance element itself is not limited.

In other words, the impedance element through which a low-frequency load current flows, which is inserted in series with the power line as described above, can be constructed of a coil with a small core, which has a lower impedance value than the conventional one, has a small number of turns per turn, and is connected between the power lines. Impedance elements can now have higher impedance values than before, making it possible to use capacitors with small capacitance or coils with small winding diameters.As a result, not only each element but also the overall shape A block filter for power line conveyance, which can be made small and has excellent workability and aesthetic appearance, is constructed.

Furthermore, since the circuit configuration is symmetrical, the same signal attenuation characteristics can be obtained even if the signal input power is reversed, which not only prevents signal leakage from within the system, but also prevents system damage due to external input signals. Malfunctions are prevented.

(Example) Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a diagram showing an embodiment of the power line carrying block filter 4 of the present invention, where 5 and 5' are a pair of power lines as signal transmission paths, and 6 and 7 are an inductor LL, a capacitor C1, and a resistor R1, respectively. , and inductor L2. Depends on capacitor C2 and resistor R2. The first . Second impedance element.

8 and 9 are inductor L3 and capacitor C, respectively.
A third impedance element is formed by an LC circuit whose resonance point is the signal frequency using the inductor L4, the capacitor C4, and the resistor R4, and a fourth impedance element is formed by an LC circuit whose resonance point is the signal frequency by the inductor L4, the capacitor C4, and the resistor R4. It is. Further, 10, 11, 10' and 11' are connection terminals for connecting the block filter 4 to the power lines 5 and 5'.

The 6 to 9 impedance elements each have an impedance value of zl, z, z, z4 at the signal frequency, and satisfy an impedance ratio of z: z, = z: z.

The present invention is configured as described above, and the impedance element 6
, 7 are configured as LCR parallel resonant circuits, so
The impedance of the parallel portion of the inductor and capacitor reaches its maximum value at the signal frequency of the resonance point, and the overall impedance is the parallel impedance value 21 of the resistance value of the resistor and the parallel resistance of the inductor and capacitor.
．． 2. It also has low impedance for low-frequency load currents, so it transmits power with low loss.

Since the impedance elements 8 and 9 are configured as an LCR series resonant circuit, the impedance element in the series part of the inductor and capacitor takes a minimum value at the signal frequency which is the resonance point, and the overall impedance value is determined by the resistance of the resistor part. 2, 2, which is the sum of the value and the series resistance of the inductor and capacitor. Low frequencies are cut off by the capacitor, so no power is consumed and no large current flows through the inductor or resistor.

When a signal with a voltage value E1 is input from the terminal 10, the voltage value E 1 ” (Z4/ZZ-Zz
/Z a )·A voltage value is output. In addition, A is Z
□.

2,,2. , 2. It is a coefficient expressed as The ratio of each impedance value of Z□ to z2 is 2:23=2:
2. Since the following relationship is satisfied, the signal voltage across the terminal 11 is calculated to be zero. Also, the above zl: z, =
By approaching the relationship z,: z, even if it does not satisfy the relationship, the value of the output signal can be reduced regardless of the size of each impedance value itself.

Therefore, high signal attenuation performance can be obtained.

Similarly, for the input signal from terminal 11, the signal voltage output to terminal 10 on the opposite side is Z, /Z2-Z1
/Z, high signal attenuation performance can be obtained.

21,2. Since a load current, which is a large low-frequency current, flows through the component inductors LL and L2, it is preferable to use an inductance with as few turns as possible in order to prevent heat generation and current saturation. , 2. If the inductance is increased, the inductance must be increased, so the shape of the core becomes larger.According to the present invention, 21.
2. may be small, and the inductor Ll with a small core
, L2.

In addition, inductor L3.za, which is a component of Z4. L
4 is combined with capacitors C3 and C4 respectively to form a series resonant circuit, and in order to reduce the M resonance impedance, inductor L3. To keep L4 loss as low as possible.

An inductor with a large winding diameter must be used.

According to the present invention, 2. , 2. The value of can be large;
It is possible to configure R3 and R4 using an inductor with a thin winding, or in other words, a small shape.

In the present invention, Zl is an impedance expressed by pure resistance, and z3 is the sum of the series resistance of resistor R3 and inductor L3, and the series resistance of capacitor C3, so the ratio of z, near 3 can be adjusted almost arbitrarily by appropriately selecting the resistor R3. Similarly 24.2. Even in this relationship, the ratio z4:Z can be arbitrarily adjusted by appropriately selecting the resistor R4.

One embodiment of the present invention has been described above, but each embodiment
The first . A second impedance element is inserted in series to each of the pair of power lines,
LCR from the signal input side of Zl to the signal output side of 22
It is composed of a series resonant circuit and connects a third impedance element having a resonant impedance Z3 at the signal frequency, and is composed of an LCR series resonant circuit from the signal input side of Zl to the signal output side of Z2, and has a resonant impedance Z3 at the signal frequency. Zl: Za
= Z4: With a circuit configuration that satisfies the condition of Zz,
A small block filter for power line transport that can obtain attenuation characteristics from both directions without using a large inductor, has excellent workability and installation appearance, and can prevent malfunctions due to signals from outside the system. can be realized.

Note that the first to fourth impedance elements 6 to 9
have a resonant impedance at the signal frequency, and obtained damping characteristics by adjusting the resistance values of resistors R3 and R4, but resistors R1 to R4 may also be adjusted.
The impedance elements 2 to z4 may be configured to adjust both the resistance component, the actance component, and C, without using the signal frequency as the resonance point.

Furthermore, the first. LC the second impedance element 6°7
R parallel circuit, 3rd. Fourth impedance element 8, 9
were each constructed using an LCR series circuit, but this means that the overall configuration of each impedance element is zl: z, =
z4: It is sufficient if the condition of z is satisfied, and the first condition is satisfied. The second impedance element is an inductor, and the third impedance element is an inductor. The fourth one is composed of a series circuit of an inductor and a capacitor,
Depending on the ratio of the inductances of the first to fourth impedance elements, the following condition may be satisfied: z: z: = z4: z2.

(Effects of the Invention) As is clear from the above description, the present invention provides a first power line connected in series to a pair of power lines, respectively. A second impedance element is connected, and a third impedance element is connected from the signal input side of the first impedance element to the signal output side of the second impedance element, and the signal of the first impedance element is connected. A fourth impedance element is connected from the output side to the signal input side of the second impedance element, and between the impedance values Z1 to 24 at the signal frequency of each impedance element, 2 steps:
2. =24: 2. By satisfying the following relationship, the shape of each impedance element is small and bidirectional attenuation is achieved.It is compact and has excellent workability and installation appearance, and it also prevents malfunctions due to signal input from outside the system. , it has greatly contributed to the modern information society.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing a block filter used in a conventional power line transport system. 1.4...Block filter, 2.2'5.5'
...Power line, 6,7,8.9 ...Impedance element. Fig. 1 9-31 iS4 in-behance search) (1 to 1)

Claims (3)

[Claims] (1) For each line constituting a pair of power lines, the first,
The second impedance elements are connected in series, and a third impedance element is connected from the signal input side of the first impedance element to the signal output side of the second impedance element, and a third impedance element is connected to the first impedance element. A fourth impedance element is connected from the signal output side of the second impedance element to the signal input side of the second impedance element, respectively.
The impedance value of each of the first to fourth impedance elements at the carrier signal frequency is Z_1.
or Z_4, Z_1:Z_3=Z_4:Z
A block filter for power line transport characterized by satisfying the relationship _2. (2) The first and second impedance elements are connected by a parallel circuit including an inductor, a capacitor, and a resistor;
, the fourth impedance element is constituted by a series circuit including an inductor, a capacitor, and a resistor. (3) Claim (1) characterized in that the first and second impedance elements are constituted by circuits including inductors, and the third and fourth impedance elements are constituted by series circuits including inductors and capacitors. ) block filter for power line conveyance.