JPS6128438Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a block filter used in a power line carrier control system that remotely controls equipment by superimposing a carrier high frequency modulated by an equipment control signal onto a commercial power source.

Conventionally, it has been used as a block filter to prevent commercial power on which external noise has been superimposed from being supplied to a load, and to prevent the noise generated by this load from being superimposed on the commercial power and having an adverse effect on other loads. There was something like the one shown in Figure 1. That is, the commercial power supply AC is applied to the load 5 via the LC parallel resonant circuits 3 and 4, and the LC series resonant circuit 2 is connected in parallel with the commercial power supply AC, and the resonant frequency of the LC parallel resonant circuits 3 and 4 is The frequency of the internal noise generated in the load 5 (generally much higher than the commercial power supply frequency) is set to be approximately equal to the frequency to increase the impedance against internal noise, and the resonant frequency of the LC series resonant circuit 2 is set to a higher frequency side than the commercial power supply frequency. By setting Q to be small and providing broad resonance characteristics, it is possible to prevent internal noise from being superimposed on the commercial power supply and to prevent external noise from being input to the load 5. was. However, such a block filter
When commercial power is supplied to the load via BF', the commercial power AC side, that is, the input side of block filter BF' is short-circuited at high frequency by the LC series resonant circuit 2.
There was a problem in that the power line on the power supply side from BF' could not be used as a transmission line for a remote control system that transmitted a carrier high frequency modulated by a device control signal. For example, if a large number of branch lines branch from the main power line are wired, and commercial power is supplied via a block filter to a load connected to one of the branch power lines, the main power line and other branch power Since the lines are short-circuited in terms of high frequency and the attenuation of the carrier high frequency of the remote control system becomes large, there is a drawback that the carrier high frequency cannot be transmitted using these power supply lines. The present invention aims to solve the above-mentioned drawbacks.

Examples will be described below using figures. Second
The figure shows an embodiment of the present invention, in which a commercial power supply AC on which a carrier radio frequency for remote control of equipment is superimposed has a resonance frequency approximately equal to the frequency of the carrier radio frequency.
The series circuit of LC parallel resonant circuit 1 and LC series resonant circuit 2, which has resonance characteristics broader on the high frequency side than the commercial power supply frequency, are connected in parallel, and the frequency of internal noise generated in the load is applied to both ends of this LC series resonant circuit. A load 5 is connected via LC parallel resonant circuits 3 and 4 having a resonant frequency substantially equal to . In the figure, C ₁ to C ₄ are capacitors, and L ₁ to _{L 4} are Q-dump resistors that broaden the resonance characteristics.

Fig. 3 shows an example of the use of the block filter BF according to the present invention, in which commercial power AC is connected to the load via the main power line _l0 such as a bus duct and the branch power lines _lk , _lb , _lo ... Transmitters T _K , T _{B , T N transmit power to each power supply line l 0 , l k , l b , and lo to transmit} a carrier high frequency modulated with a device control signal, and receive the modulated carrier high frequency. It has come to be used as a carrier high-frequency transmission line for a remote control system consisting of receivers R _K , _RB , and _RN for controlling equipment. In this case, the LC parallel resonant circuit 1 on the input side of the block filter BF resonates with the carrier high frequency and becomes high impedance, so even if the LC series resonant circuit 2 has a low impedance with respect to the carrier high frequency, the main power supply lines l ₀ and The branch power lines l _k and _lo have high impedance with respect to the carrier high frequency, and the main power line l ₀ and the branch power lines l _{k and lo} are not short-circuited as in the conventional example. . Furthermore, the impedance of the LC parallel resonant circuit 1 is low at frequencies other than the frequency of the carrier high frequency, and the LC series resonant circuit 2 is also low at frequencies higher than the commercial power frequency. The effect of blocking external noise (including carrier high frequency) having a frequency higher than the commercial power supply frequency is not impaired.

As described above, the present invention uses an LC parallel resonant circuit that has a resonant frequency approximately equal to the frequency of the carrier high frequency for the commercial power supply on which the carrier high frequency for remote control of equipment is superimposed, and a resonance characteristic that is broader on the higher frequency side than the commercial power supply frequency. An LC series resonant circuit and a series circuit are connected in parallel, and a load is connected to both ends of the LC series resonant circuit via an LC parallel resonant circuit having a resonant frequency approximately equal to the frequency of internal noise generated within the load. An LC parallel resonant circuit having a frequency approximately equal to the frequency of the carrier high frequency is inserted in series on the input side, and the input side impedance is higher than the carrier high frequency. This has the advantage that when supplying commercial power to a load using a power line, the power line on the input side of the block filter can be used as a transmission line for a power line carrier remote control system that transmits signals using a carrier high frequency. It is.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional example, FIG. 2 is a circuit diagram of an embodiment of the present invention, and FIG. 3 is a circuit diagram showing an example of use of the same. AC is an alternating current power supply, 1, 3, and 4 are LC parallel resonant circuits, 2 is an LC series resonant circuit, and BF is a block filter circuit.

Claims (1)

[Scope of utility model registration request] An LC parallel resonant circuit that has a resonant frequency approximately equal to the frequency of the carrier high frequency on a commercial power supply on which a carrier high frequency for remote control of equipment is superimposed, and an LC series resonant circuit that has a resonance characteristic that is broader on the higher frequency side than the commercial power supply frequency. Connect the series circuits in parallel to obtain the above LC
A block filter circuit consisting of a series resonant circuit and a load connected to both ends via an LC parallel resonant circuit that has a resonant frequency approximately equal to the frequency of internal noise generated within the load.