JP5178482B2 - Wireless communication system - Google Patents

Description

  The present invention relates to a wireless communication system.

In recent years, a surge as disclosed in Patent Document 1 on a lightning surge intrusion path (antenna or the like) of a wireless communication device in order to protect against a high-frequency transient overvoltage generated by a lightning strike, a so-called lightning surge. An absorber (lightning arrester) may be provided. The surge absorber prevents lightning surges from escaping to the ground, thereby preventing damage to the inside of the wireless communication device. In addition to protecting against lightning surges, wireless communication devices need to detect lightning surges for control of alarm output and malfunction prevention. However, lightning surges cannot be detected with a surge absorber alone. For this reason, a surge sensor for detecting a lightning surge as disclosed in Patent Document 2 is required separately from the surge absorber.
JP 2007-259622 A Japanese Patent Laid-Open No. 2002-277489

  However, when the surge absorber and the surge sensor are individually provided for the wireless communication device, not only the size of the surge absorber and the surge sensor but also a power source is required for each. For this reason, there existed a problem that the system scale containing a surge absorber, a surge sensor, and a radio | wireless communication apparatus became large.

  The present invention has been made in view of the above problems, and a main object of the present invention is to provide a wireless communication system capable of protecting against lightning surge and detecting lightning surge while suppressing the system scale.

A main aspect of the present invention for solving the above-described problem is a wireless communication system having an antenna and a wireless communication module that transmits and receives via the antenna, wherein one electrode is disposed between the antenna and the wireless communication module. A coherer that is connected to the first signal line and whose other electrode is grounded to a low level and is shifted from an insulated state to a short-circuit state by a lightning surge received by the antenna, and a detection that detects the lightning surge received by the antenna And
A pull-up resistor whose one terminal is connected to a high-level power supply voltage and whose other terminal is connected to the input port of the detection unit, and a second between the first signal line and one electrode of the coherer. A high-frequency blocking coil provided between the signal line and a third signal line between the other terminal of the pull-up resistor and the input port of the detection unit, and the detection unit includes the input The lightning surge is detected when the input to the port changes from the high level to the low level.

  Further, in the wireless communication system described above, the detection unit has a function of controlling transmission / reception via the antenna by the wireless communication module, and a predetermined period elapses after the lightning surge is detected. In the meantime, control for stopping transmission / reception via the antenna by the wireless communication module may be performed.

  Further, in the wireless communication system described above, the decohealer is connected to an output port of the detection unit, vibrates the coherer, and returns a short circuit state of the coherer due to the lightning surge to an insulating state, A detection part is good also as performing control which operates the decohealer when the predetermined period passes after detecting the lightning surge.

  Further, in the wireless communication system described above, when the detection unit operates the decoherer to return the short circuit state of the coherer to an insulating state, the detection unit transmits and receives via the antenna to the wireless communication module. It is good also as performing control which cancels | releases this stop.

  Further, in the wireless communication system described above, the detection unit detects the lightning surge to the wireless communication module after releasing the stop of transmission / reception via the antenna from the wireless communication module. It is good also as performing control which transmits the transmission signal which shows that via the said antenna.

  In addition, the problems disclosed in the present application and the solutions thereof will be clarified by the column of the best mode for carrying out the invention and the drawings.

  As shown in the present invention, it is possible to provide a wireless communication system capable of protecting against lightning surge and detecting lightning surge while suppressing the system scale.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

<<< Configuration of Wireless Communication System >>>
FIG. 1 is a diagram showing a configuration of a wireless communication system according to an embodiment of the present invention. The wireless communication system 100 shown in FIG. 1 is a system for performing predetermined wireless communication installed on a steel tower on which transmission and distribution lines are installed. Not only a function for performing predetermined wireless communication, but also a coherer 130 and a decoherer described later. It has a function of protecting from lightning surge using 170 and a function of detecting lightning surge. In the case of the function of detecting a lightning surge, a lightning surge detection signal S indicating that a lightning surge accompanying a lightning strike that has occurred on the tower where the lightning device is installed is installed at a power company branch or sales office. Send to a server (not shown).

  The wireless communication system 100 includes a wireless communication module 110, an antenna 120, a coherer 130, an MCU (Micro Control Unit) 140, a pull-up resistor 150, a high-frequency blocking coil 160, and a decoherer 170.

  The wireless communication module 110 receives the reception signal A received by the antenna 120 via the first signal line 122, and demodulates the input reception signal A according to a predetermined communication protocol. The demodulated signal is output to a predetermined output device (not shown). Further, the wireless communication module 110 modulates information to be transmitted into a transmission signal D according to a predetermined communication protocol and transmits the modulated signal via the antenna 120.

  In the coherer 130, one electrode 134a is connected to the first signal line 122 between the antenna 120 and the wireless communication module 110, and the other electrode 134b is connected (grounded) to a ground having a low level potential. As shown in FIG. 2, the coherer 130 has a structure in which a metal powder 132 such as nickel is sandwiched between a pair of electrodes 134 a and 134 b and these are covered with an insulator 136. The electrical resistance between the electrodes 134 in a normal state is high and is almost in an insulating state (Hi-Z state). In short, it has a characteristic of being in a short circuit state (coherence).

  It is known that the change in electric field strength due to typical lightning discharge reaches about 120 V / m at the maximum in 100 μS. On the other hand, it has a characteristic that it has low sensitivity and hardly reacts to a gradual change in electric field strength. In addition, once it is in a conductive state, it has a characteristic that it does not return to the original insulating state even if the current is cut off. In order to return to the original insulating state, a decoherer 170 described later is required.

  FIG. 3 shows time characteristics according to the applied voltage of the coherer 130. The coherer 130 has a structure in which constant voltage diodes are reversely connected in parallel through a point contact formation period in which a point contact is formed between the electrode 134 and the metal powder 132 or between the metal powders 132 due to an increase in applied voltage. When the applied voltage reaches the breakdown voltage, the operation proceeds to the short-circuit operation period, and the operation proceeds to the voltage limit characteristic operation period (the voltage between the electrodes 134 is limited between the breakdown voltage and the breakdown voltage). .

  The MCU 140 includes a DI (Data Input) port 142 and a DO (Data Output) port 144. The DI port 142 is connected to the pull-up resistor 150 and the high frequency blocking coil 160. DO port 144 is connected to decohealer 170. The MCU 140 performs overall control of transmission / reception via the antenna 120 by the wireless communication module 110, and in particular, a function for controlling whether transmission / reception of the wireless communication module 110 is enabled or disabled, and a DI port 142. And a function of detecting a lightning surge accompanying a lightning strike based on an input level (High level: lightning surge not detected, Low level: lightning surge detected). Furthermore, it has a function of operating or stopping the decoherer 170 based on the level output from the DO port 144 (High level: operation of the decoherer 170, Low level: stop of the decoherer 170). In addition, you may implement as a processor provided with CPU and memory other than MCU140, and you may implement said two functions as a separate processor.

  The pull-up resistor 150 has one terminal connected to the power supply voltage VCC corresponding to the high level voltage in the MCU 140 and the other terminal connected to the DI port 142 of the MCU 140. The high frequency blocking coil 160 connects the second signal line 124 connecting the first signal line 122 and one electrode 134 a of the coherer 130, and the other terminal of the pull-up resistor 150 and the DI port 142. The third signal line 155 is provided. The high-frequency blocking coil 160 is also called a choke coil or a line filter, and is a coil that blocks the passage of a high-frequency current (lightning surge) exceeding a predetermined frequency.

  The decoherer 170 is a device for returning the coherer 130 that has been short-circuited to the original insulating state. The deco-healer 170 includes, for example, a piezoelectric element and an electromagnet, and ultrasonic waves (20 kHz or more) from the above-described piezoelectric element and electromagnet based on a command (High level: operation, Low level: stop) output from the DO port 144 of the MCU 140. ) And the insulator 136 of the coherer 130 is vibrated to return the coherer 130 from the short-circuited state to the original insulating state.

<<< Operation of Wireless Communication System >>>
FIG. 4 is a timing chart showing the operation of the wireless communication system 100. Assuming that time elapses in the order of times t0, t1, t2, and t3 shown in the figure, a lightning surge occurs at time t1, the coherer 130 operates, the decoherer 170 operates at time t2, and at time t3. The case where the coherer 130 returns is shown.

  From time t0 to time t1, no lightning strike has occurred, the change in the electric field strength of the received signal A received by the antenna 120 is gentle, and the coherer 130 maintains the insulation state (Hi-Z state). ing. For this reason, the reception signal A is input to the wireless communication module 110 without going to the DI port 142 of the MCU 140 via the coherer 130 or the high frequency blocking coil 160. Further, a high level corresponding to the power supply voltage VCC is input to the DI port 142 via the pull-up resistor 150, and in response to this, the MCU 140 outputs a communication control signal C instructing the wireless communication module 110 to enable transmission / reception. To do.

  At time t1, a sudden and large change in electric field strength (lightning surge) of the received signal A occurs with a lightning strike, and the coherer 130 shifts from the insulated state to the short-circuited state. For this reason, the reception signal A does not flow toward the wireless communication module 110 but flows toward the ground via the coherer 130. At this time, the coherer 130 realizes a function as a surge absorber that protects the wireless communication module 110 from lightning surge.

  Further, the received signal A when a lightning strike is at a high frequency, and the high frequency blocking coil 160 blocks the input of the high frequency component of the received signal A toward the DI port 142 of the MCU 140. Since the high-frequency blocking coil 160 can pass a DC component of the reception signal A, the low level of the ground is input to the DI port 142 of the MCU 140 via the coherer 130. As a result, the MCU 140 has detected a lightning surge in response to the change in the input level of the DI port 142 from the high level to the low level. Then, the MCU 140 outputs a communication control signal C instructing the wireless communication module 110 to stop transmission / reception in order to prevent an invalid transmission signal D having a large noise or the like from being transmitted from the antenna 120.

  At time t2 when a predetermined period T0 has elapsed from time t1, the decoherer 170 operates based on a command (high level) from the DO port 144 of the MCU 140, and the coherer 130 starts to shift from the short-circuited state to the original insulated state. To do.

  At time t3, the coherer 130 returns from the short-circuited state to the original insulated state, and returns to the state from time t0 to time t1 when no lightning strike has occurred. That is, a high level corresponding to the power supply voltage VCC is input to the DI port 142 via the pull-up resistor 150. In response to the change in the input level of the DI port 142 from the Low level to the High level, the MCU 140 instructs the wireless communication module 110 to transmit a lightning surge detection signal S indicating that a lightning surge has been detected, and to stop transmission / reception. A communication control signal C instructing release is output. At this time, the MCU 140 realizes a function of detecting a lightning surge.

  Then, the wireless communication module 110 can modulate the lightning surge detection signal S instructed from the MCU 140 into a transmission signal D according to a predetermined communication protocol and transmit it from the antenna 120. As a result, the branch office or sales office of the electric power company that has received the transmission signal D can grasp the steel tower where the lightning strike has occurred, and can quickly perform subsequent maintenance.

  As described above, the wireless communication system 100 functions as a surge absorber that protects the wireless communication module 110 from lightning surges in a small-scale system configuration using the coherer 130, the decoherer 170, the MCU 140, and the like without using a surge absorber or a surge sensor. And a function of detecting a lightning surge can be realized. The coherer 130 does not require a power source because it operates with a lightning surge.

  Although the best mode for carrying out the present invention has been described above, the above embodiment is intended to facilitate understanding of the present invention and is not intended to limit the present invention. . The present invention can be changed and improved without departing from the gist thereof, and equivalents thereof are also included in the present invention.

It is the figure which showed the structure of the radio | wireless communications system which concerns on one Embodiment of this invention. It is the figure which showed the structure of the coherer which concerns on one Embodiment of this invention. It is the figure which showed the time characteristic according to the applied voltage of the coherer which concerns on one Embodiment of this invention. 6 is a timing chart illustrating an operation of the wireless communication system according to the embodiment of the present invention.

Explanation of symbols

100 wireless communication system 110 wireless communication module 120 antenna 122 signal line 130 coherer 132 metal powder 134a, 134b electrode 136 insulator 140 MCU
142 DI port 144 DO port 150 Pull-up resistor 155 Signal line 160 High-frequency blocking coil 124 Signal line 170 Decohealer

Claims (5)

A wireless communication system having an antenna and a wireless communication module that transmits and receives via the antenna,
One electrode is connected to the first signal line between the antenna and the wireless communication module, and the other electrode is grounded to the low level, and the lightning surge received by the antenna shifts from the insulation state to the short-circuit state. Coherer to do,
A detector for detecting a lightning surge received by the antenna;
A pull-up resistor having one terminal connected to a high level power supply voltage and the other terminal connected to the input port of the detection unit;
Between the second signal line between the first signal line and one electrode of the coherer, and the third signal line between the other terminal of the pull-up resistor and the input port of the detection unit. A high-frequency blocking coil provided,
The detecting unit detects the lightning surge when an input to the input port changes from the high level to the low level;
A wireless communication system. The wireless communication system according to claim 1,
The detection unit has a function of controlling transmission / reception through the antenna by the wireless communication module, and detects a lightning surge and passes through the antenna by the wireless communication module until a predetermined period elapses. Control to stop transmission / reception
A wireless communication system. The wireless communication system according to claim 2,
A decohealer connected to the output port of the detection unit, oscillating the coherer and returning the short circuited state of the coherer due to the lightning surge to an insulated state;
The detection unit performs a control to operate the decohealer when the predetermined period has elapsed after detecting the lightning surge;
A wireless communication system. A wireless communication system according to claim 3,
The detection unit, when operating the decoherer to return the short circuit state of the coherer to an insulating state, performs a control to release the stop of transmission and reception through the antenna to the wireless communication module,
A wireless communication system. The wireless communication system according to claim 4,
The detection unit causes the wireless communication module to cancel transmission / reception stop via the antenna and then causes the wireless communication module to transmit a transmission signal indicating that the lightning surge has been detected via the antenna. Doing control,
A wireless communication system.

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