JPS6318197Y2 - - Google Patents

Description

[Detailed description of the invention] This invention uses the metal circuit of the distribution line to transmit audio frequency signal radio waves from the load side to the power supply end, or
A current carrier that transmits from the consumer end to the secondary side of a pole transformer and is used to monitor line switches, transmit distribution line information such as voltage, current, and load management of distribution lines, and meter reading data from watt-hour meters. It concerns the transmitter.

As shown in Fig. 1, a transmitter in a current carrier system that transmits an audio frequency signal current from the load side to the power supply end using a distribution line as a transmission path transmits an audio frequency sine wave current generated by an oscillator 1. There is a method that is amplified by an amplifier 2 and injected into the low-voltage distribution line 4 through a coupling circuit 3 consisting of capacitors C ₁ and C ₂ and a transformer T ₁ , but the coupling circuit 3 has the disadvantage of being expensive and large in size. Ta.

Further, as shown in FIG. 2, a full-wave rectifier 5,
It is turned on and off by the pulse 6 of the signal frequency, and the resistors R ₁ to _{R 3} and the signal level adjustment switches S ₁ to _{S 3}
It has been proposed that a signal current is injected into the low-voltage distribution line 4 by a chopper circuit 8 formed from a transistor 7 that interrupts the current flowing through a selected one circuit. Since a large current flows through the switches S ₁ to _{S 3} ,
It has been difficult to downsize the switch portion and improve the quick response of switching.

The purpose of the present invention is to provide a current carrying transmitter which can solve the above-mentioned problems, has a signal current level adjustment means with excellent quick response, and can be made compact and inexpensive. It is.

In order to achieve this objective, the present invention connects a signal level adjustment transformer with a larger number of turns on the secondary side than the primary side as an impedance connected in series with a chopper circuit between the lines of the distribution line. The present invention is characterized in that impedance variable means for varying the composite impedance seen from the primary side is provided on the secondary side of the signal level adjustment transformer.

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

FIG. 3 is a circuit diagram showing an embodiment of the present invention. The transmitter includes a rectifier 5 connected between the lines of the low-voltage distribution line 4, a signal level adjustment transformer _TR , and a variable resistor R _V provided in its secondary circuit.
A transistor 7 is turned on and off by an audio frequency pulse 6. The alternating current of the low-voltage distribution line 4 is rectified into direct current by the rectifier 5, and a signal level adjusting transformer _TR having a variable resistor R _V as impedance variable means on the secondary side is used to adjust the transmission distance. Also, the necessary signal level is maintained to distinguish between noise current and signal current. The transistor 7 is turned on and off by the audio frequency pulse 6, thereby intermittent the current on the primary side of the signal level adjustment transformer _TR , shapes the signal current into a chopper waveform, and converts the signal current into a chopper waveform signal current. Therefore, information is transmitted from the load side to the power source end (not shown) via the low voltage distribution line 4. The signal level adjustment transformer _TR uses a transformer with a larger number of turns on the secondary side than on the primary side, so the variable resistor R _V used to operate the signal level adjustment transformer _TR reduces the flowing current. Therefore, the adjustment means can be made compact,
It can be made easy to operate.

4, 5, 6, 7, and 8 are circuit diagrams showing other embodiments of the present invention, all of which have almost the same circuit configuration as the embodiment shown in FIG. They have different structures in terms of means for varying the combined impedance on the secondary side of the transformer _TR . The same parts as in FIG. 3 are designated by the same reference numerals.

The signal level adjustment transformer _TR shown in Fig. 4 is
By short-circuiting any one of the winding taps T _P1 to _{T P3} provided on the secondary side, the combined impedance seen from the primary side of the signal level adjusting transformer _TR is changed. R _B is the resistance.

The signal level adjustment transformer _TR shown in Fig. 5 is
Winding taps T _P1 to _{T P3} , selection switches S _B1 to _{S B3} , and resistors R _B , the signal level shown in Fig. 6 is controlled by selection switches S _B1 to _{S B3} , and resistors R _B1 to _{R B3} . This changes the composite impedance seen from the primary side of the adjustment transformer _TR . In these cases, in order to ensure synchronization with the terminal equipment (not shown), the signal level may be changed, for example by setting the start pulse to 200% and subsequent pulses to 100%, or by changing the signal level of the power distribution line. measure the noise,
When changing the signal level each time based on this, by using electronic switches as the respective selection switches S _B1 to _{S B3} , quick switching operations can be performed and highly reliable information can be easily obtained. Moreover, it can be sent quickly.

Figures 7 and 8 show that the signal level adjustment transformer _TR is
FIG. 2 is a circuit diagram showing an embodiment provided on the alternating current side of the rectifier 5. FIG. Figure 7 shows that the _8th
The figure shows an example in which winding taps T _P1 to T _P3 constitute means for varying the combined impedance.

The embodiments shown in FIGS. 3, 4, 5, 6, 7, and 8 are as follows:
By increasing the number of turns on the secondary side of the signal level adjustment transformer T _R than on the primary side, and providing variable impedance means for adjusting the signal level on the secondary side where the current is small, it is possible to change the signal current as necessary. , can easily respond quickly.

In the embodiment of the present invention, a full-wave rectifier 5 is used, but a half-wave rectifier can also be used. Also, a thyristor or a bidirectional thyristor may be used in place of the transistor 7, in which case the rectifier 5
becomes unnecessary.

In addition, the variable resistor R _V shown in FIG. 3, the winding taps T _P1 to T P3 and the resistor R _B shown in FIG. 4, the winding taps T _P1 to _{T P3 and} the selection switches S _B1 to S shown in FIG. _B3
and resistors R _B , selection switches S _B1 to _{S B3} and resistors R _B1 to R _B3 shown in FIG. 6, variable resistors R _V shown in FIG. 7, and winding taps T _P1 to T _P3 and resistors shown in FIG. R _B corresponds to the impedance variable means of the present invention.

As explained above, according to the present invention, a signal level adjustment transformer with a larger number of turns on the secondary side than on the primary side is connected as an impedance connected in series with a chopper circuit between the lines of a distribution line, and Since the variable impedance means for varying the composite impedance seen from the primary side is provided on the secondary side of the signal level adjustment transformer, the current flowing through the variable impedance means can be reduced, and the variable impedance means can be quickly responsive. Make it excellent;
It can be made small and inexpensive.

[Brief explanation of the drawing]

1 and 2 are circuit diagrams showing examples of conventional distribution line current carrying transmitters, and FIGS. 3, 4, 5, 6, 7, and 8 are circuit diagrams showing embodiments of the present invention, respectively. 4...Low voltage distribution line, 5...Full wave rectifier, 6...
Audio frequency pulse, 7...transistor, T _R
...Transformer for signal level adjustment, R _B ...Resistor,
R _V ...Variable resistance, S _B1 ~ S _B3 ...Selection switch,
T _P1 ~ T _P3 ... Winding tap, R _B1 ~ _{R B3} ... Resistance.

Claims (1)

[Scope of utility model registration request] In a current carrier transmitter, an impedance and a chopper circuit are connected in series between the lines of a distribution line, and the current flowing through the impedance is interrupted at a signal frequency by the chopper circuit. A current transfer device characterized in that a signal level adjusting transformer having a large number of turns on the side is connected, and impedance variable means for varying the composite impedance seen from the primary side is provided on the secondary side of the signal level adjusting transformer. transmitter.