JP4461537B2 - Power line carrier communication equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power line carrier communication device that performs communication via a power feed line, and is particularly applied to a non-contact power feed device that supplies power from a ground side to a moving body such as a transport vehicle that travels on a track in a non-contact state. The present invention relates to a power line carrier communication device.
[0002]
[Prior art]
Conventionally, unmanned factories have been promoted as part of factory automation, and materials are transported on the premises by unmanned transport vehicles. In accordance with a command from the control unit installed on the ground side, this transport vehicle travels on the track to the place where the goods to be transported are placed, stops at a predetermined position, and loads the goods to the destination. It is designed to be transported.
[0003]
As a power supply device for this transport vehicle, there is a so-called non-contact power supply device that supplies power to the transport vehicle from the ground side without directly contacting the transport vehicle. This power supply device includes a primary side circuit / feed line that generates a high frequency magnetic field by supplying a high frequency current (alternating current power) to a power supply line attached to a track, and is mounted on the carrier side so as to be magnetically connected to the primary side. And a secondary side circuit coupled to the primary side circuit, and configured to supply power from the primary side circuit to the secondary side circuit via a magnetic field. In the case of this non-contact power supply device, unlike so-called trolley power supply, power is supplied in a non-contact manner, so that maintenance work such as brushes is unnecessary, and above all, dust and dirt caused by contact with the running brush etc. There is no generation of dust and the like, which is convenient for application in a clean atmosphere such as a clean room.
[0004]
In this type of unmanned conveyance system, it is necessary to control an unmanned conveyance vehicle, and communication is performed between the control unit on the ground side and the conveyance vehicle. There is a so-called power line carrier communication device that superimposes signals and uses a feeder line as a transmission path for communication signals.
[0005]
FIG. 4 schematically shows a primary circuit of a non-contact power feeding device to which a conventional power line carrier communication device is applied. In the figure, reference numeral 10 denotes a high-frequency power source that generates a high-frequency current. Reference numeral 20 denotes a power supply line that generates a magnetic field when a high-frequency current is supplied from the high-frequency power supply 10. The feeder line 20 is folded in the vicinity of the middle, and is attached to a track 30 that is a traveling path of the transport vehicle, with one line 20A and the other line 20B up to the turning point as a pair of parallel lines. . The feeder line 20 is connected to the high-frequency power source 10, and high-frequency currents having a phase difference of 180 degrees are respectively supplied to the line 20A and the line 20B.
[0006]
Here, the ground-side communication transformer 40 of the power line carrier communication device is installed near the high-frequency power supply 10 and is magnetically coupled to the power supply line 20, and the carrier-side communication transformer 50 of this power line carrier communication device is It is mounted on the transport vehicle and is magnetically coupled to the feeder line 20. The ground side communication device and the carrier vehicle side communication device (both not shown) of the power line carrier communication device are connected to the feeder line 20 via these communication transformers, and the ground side and carrier vehicle side via the feeder line 20 are connected. Communication between them.
[0007]
According to this power line carrier communication device, for example, when a communication signal including a digital code is transmitted from the ground side to the carrier vehicle, the logical value “0” is associated with a lower frequency of a frequency of several hundred kHz, and the logical value “1”. "Is associated with a higher frequency, and a combination of frequency components corresponding to the content of the communication signal is superimposed on the power component on the feeder 20 via the ground communication transformer 40 and transmitted. The transport vehicle on the track receives the communication signal superimposed on the power component via the transport vehicle-side communication transformer 50.
[0008]
[Problems to be solved by the invention]
By the way, according to the above-described configuration of the prior art, when the line length from the ground-side communication transformer 40 to the turn-around point of the feed line 20 is around a quarter wavelength of the communication signal, the communication signal is placed on the feed line 20. There is a problem that a standing wave is generated and an area where communication is impossible occurs on the orbit.
[0009]
This mechanism will be described with reference to FIGS.
The above-described feed line 20 shown in FIG. 4 forms a distributed constant circuit, and as shown in FIG. 5, the end Tb of the parallel line made up of the line 20A and the line 20B (part corresponding to the turning point of the feed line 20). Equivalent to short-circuiting. For this reason, reflection occurs at the end Tb of the parallel line, and when the line length between the start end Ta and the end Tb of the parallel line becomes approximately a quarter wavelength of the communication signal, as shown in FIG. A standing wave of a communication signal (communication current) having a node (resonance point) in the vicinity is generated on the parallel lines. As a result, the amplitude of the communication signal in the vicinity of the start end Ta becomes extremely small, and when the transport vehicle is located in the vicinity of the start end Ta, it becomes impossible to receive a communication signal from the ground side, and thus the transport vehicle cannot be controlled.
[0010]
For example, when the frequency of the communication signal is set near several hundred kHz as described above, the wavelength is at least 1000 m or more, but the signal propagation speed is reduced inside the feeder line, so that 5 minutes When it reaches about 3 and the line length is about 100 m, it is considered that standing waves appear. Therefore, there is a possibility that power line carrier wave communication becomes impossible before and after the actual line length (for example, 100 to 200 m).
[0011]
In order to avoid this, the length of the feeder line can be changed. However, if the feeder line is lengthened, power loss may increase and the supply of power may be hindered. If it is shortened, there is a disadvantage that the configuration of the apparatus becomes complicated.
[0012]
The present invention has been made in view of the above circumstances, and in power line carrier communication, a reflected wave or standing wave due to a communication signal does not occur on the feeder line, and communication between the carrier on the track and the ground side is possible. An object of the present invention is to provide a power line carrier communication device that can be used on all tracks.
[0013]
[Means for Solving the Problems]
To solve the above problems, this invention provides a contactless power supply apparatus for performing non-contact power supply to the movable body by supplying AC power to the annexed to said track along the track of the moving body feeding line, A power line carrier communication device that is applied to the non-contact power supply device and performs communication between the ground side and the mobile body via the power supply line, and is considered as an electrical terminal on the power supply line Provided with an impedance matching resistor and an LC series resonance circuit that resonates at the frequency of the AC power, and the power supply line comprises a parallel line to which the AC power is supplied at the start, and the impedance matching resistor And the LC series resonance circuit are connected in parallel between terminal ends of the parallel lines .
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a power line carrier communication apparatus according to an embodiment of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the description is abbreviate | omitted suitably.
[0017]
FIG. 1 shows a configuration on the ground side (primary side circuit) of a non-contact power feeding device to which the power line carrier communication device according to this embodiment is applied. In the figure, reference numeral 100 denotes a high-frequency power source that generates a high-frequency current. Reference numeral 200 denotes a power supply line that generates a magnetic field when a high-frequency current is supplied from the high-frequency power source 100. The feeder line 200 forms a parallel line from the line 200A and the line 200B, and is attached along a track 300 that is a traveling path of a transport vehicle (not shown). The starting end Ta of the parallel line (feed line 200) is connected to the high frequency power supply 100, and a terminating circuit 600 described later is connected to the terminating end Tb.
[0018]
The ground-side communication transformer 400 of the power line carrier communication device is installed in the vicinity of the high-frequency power source 100 and is magnetically coupled to the feeder line 200. In addition, the carrier-side communication transformer 500 of the power line carrier communication device is mounted on a carrier vehicle (not shown) and is magnetically coupled to the feeder line 200. In other words, the ground-side communication device and the carrier-side communication device (both not shown) of the power line carrier communication device are connected to the power supply line 200 via these communication transformers, and the power supply line 200 serves as a transmission path for communication signals. used. Communication between the ground side and the transport vehicle side is performed using a communication signal having a frequency of several hundred kHz, and a lower frequency component corresponding to a logical value “0” and an upper frequency corresponding to a logical value “1”. This is done by superimposing the component on the power.
[0019]
Here, as shown in FIG. 2A, the ground side communication transformer 400 is magnetically coupled to both the line 200 </ b> A and the line 200 </ b> B forming the feeder line 200. When a current having a frequency corresponding to a communication signal is supplied to the primary side winding 400A of the ground side communication transformer 400, a current component of the communication signal is induced in the line 200A and the line 200B. The power component supplied from the high-frequency power source 100 to the power supply line 200 (that is, the line 200A and the line 200B) is superposed.
[0020]
Further, as shown in FIG. 5B, the carrier-side communication transformer 500 is magnetically coupled to the lines 200A and 200B of the feeder 200 attached to the track 300, and flows through the lines 200A and 200B. The communication signal is induced in the secondary winding 500A by the current component of the communication signal. The transport vehicle-side communication transformer 500 moves along the feed line 200 together with the transport vehicle while maintaining magnetic coupling with the feed line 200.
[0021]
Further, as shown in FIG. 3, the termination circuit 600 includes an LC series resonance circuit 601 including a coil L and a capacitor C, and an impedance matching resistor R. The impedance matching resistor R and the LC series resonance circuit 601 are connected in parallel between a portion regarded as an electrical termination Tb on the feeder line 200, that is, between the termination of the line 200A forming the parallel line and the termination of the line 200B. Has been.
[0022]
Here, the resistance R for impedance matching has an impedance substantially equal to the characteristic impedance of the feeder 200 formed of the line 200A and the line 200B, and absorbs the reflected wave of the communication signal generated at the terminal Tb. The LC series resonance circuit 601 is set so as to resonate at the frequency of the AC power supplied from the high frequency power source 100. The terminal Tb of the parallel line is short-circuited with respect to the AC power in an AC manner. The AC power component supplied from 100 is passed. In addition, the values of the resistor R, the coil L, and the capacitor C constituting the termination circuit 600 are set so that the impedance of the LC series resonance circuit 601 is sufficiently larger than the impedance of the resistor R at the frequency of the communication signal. Yes.
[0023]
Hereinafter, the operation of the power line carrier communication apparatus according to this embodiment will be described with reference to FIG.
First, when a high-frequency current as power is supplied from the high-frequency power supply 100 to the feeder line 200, the LC series resonance circuit 601 of the termination circuit 600 enters a resonance state, and the line 200A and the line 200B are exchanged in an alternating manner at the termination Tb. Shorted. As a result, most of the high-frequency current supplied from the high-frequency power supply 100 flows through the power supply line 200 via the LC series resonance circuit 601 and generates a high-frequency magnetic field around the power supply line 200. As a result, the power supply of the transport vehicle 501 on the track is established, and the transport vehicle 501 becomes operable. At this time, since most of the high-frequency current supplied from the high-frequency power supply 100 flows through the LC series resonance circuit 601 and hardly flows into the impedance matching resistor R, almost no power loss occurs in the termination circuit 600.
[0024]
Next, when a communication signal for instructing a destination or the like is sent from the ground side to the transport vehicle 501 on the track, the ground side communication device sends the communication signal to the feeder 200 via the ground side communication transformer 400. Output to. As a result, the communication signal from the ground side is transmitted over the feeder line 200 while being superimposed on the high-frequency current supplied as the AC power from the high-frequency power supply 100.
[0025]
Here, the communication signal output from the ground-side communication transformer 400 installed on the start end Ta side of the parallel line propagates on the feed line 200 and reaches the end Tb side. Therefore, the reflected wave by this communication signal is not generated. Further, as described above, the LC series resonance circuit 600 does not resonate at the frequency of the communication signal, and the impedance of the LC series resonance circuit 600 is set sufficiently higher than the impedance of the resistor R. Most of the current component flows into the impedance matching resistor R side.
[0026]
For this reason, the reflected wave of the communication signal is effectively suppressed by the impedance matching resistor R, and the loss of the communication signal by the LC series resonance circuit 600 hardly occurs. Therefore, even if the line length of the feeder line 200 is, for example, a quarter wavelength of the communication signal, a standing wave of the communication signal is not formed on the feeder line 200, and the carrier vehicle 501 Communication signals transmitted from the ground side can be received in the entire area.
[0027]
Conversely, considering the case where a communication signal is transmitted from the transport vehicle 501 to the ground side, even if the communication signal output from the transport vehicle 501 reaches the terminal Tb, the impedance of the terminal Tb is similarly matched. Therefore, no reflected wave is generated by this communication signal, and no standing wave is formed. Therefore, the communication device on the ground side can receive the communication signal from the transport vehicle 501 regardless of where the transport vehicle 501 is located on the track.
[0028]
As described above, according to this embodiment, it is possible to match the impedance at the terminal without causing power loss, so that the generation of reflected waves and standing waves due to communication signals is suppressed, and the entire trajectory is reduced. Two-way communication via the feeder line 200 is possible.
[0029]
In addition, since the reflected wave at the end of the feed line 200 is suppressed, a reflected wave or standing wave due to a communication signal is formed on the feed line 200 regardless of the line length of the feed line 200. There is no. Therefore, the amplitude of the communication signal is uniform on the entire track, and the SN ratio can be stabilized over the entire track.
[0030]
The embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and the present invention includes any design changes that do not depart from the gist of the present invention. It is. For example, in the above-described embodiment, the communication signal is output to both the line 200A and the line 200B constituting the feeder line 200. However, the present invention is not limited to this, and the communication signal is output only to one line. It is good also as what to do.
Further, although only the power component is allowed to pass through the LC series resonance circuit 601, a filter circuit, for example, can be used instead of the LC series resonance circuit 601.
[0031]
【The invention's effect】
As described above, according to the present invention, the impedance matching resistor and the resonance circuit that resonates at the frequency of the AC power supplied to the power supply line are provided at the portion regarded as the electrical terminal on the power supply line. Therefore, a reflected wave or standing wave due to a communication signal is not generated on the feeder line in the power line carrier communication, and communication between the carrier on the track and the ground side is possible on the whole track.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration on the ground side of a non-contact power feeding device to which a power line carrier communication device according to an embodiment of the present invention is applied.
FIG. 2 is a circuit diagram showing configurations of a ground side communication transformer and a carrier vehicle side communication transformer of the power line carrier communication apparatus according to the embodiment of the present invention.
FIG. 3 is a circuit diagram showing a configuration of a termination circuit of the power line carrier communication device according to the embodiment of the present invention.
FIG. 4 is a diagram illustrating a configuration of a non-contact power feeding device to which a power line carrier communication device according to a conventional technique is applied.
FIG. 5 is a diagram for explaining the operation of the power line carrier communication apparatus according to the prior art.
FIG. 6 is a diagram showing a waveform of a standing wave on a feeder line by a power line carrier communication device according to the prior art.
[Explanation of symbols]
100: high frequency power source 200: feeder lines 200A, 200B; lines (parallel lines)
300: Track 400; Ground-side communication transformer 400A: Ground-side communication transformer primary winding 500; Carrier-vehicle-side communication transformer 500A; Carrier-vehicle-side communication transformer secondary-side winding 501; Carrier vehicle C; Capacitor L; Coil R: impedance matching resistor Ta; start end Tb; end

Claims (1)

A non-contact power supply apparatus that supplies AC power to a power supply line attached to the track along a track of the mobile body to perform non-contact power supply to the mobile body, and is applied to the non-contact power supply apparatus, via an electric wire a power line communication device for communicating between the ground side the moving body,
In a portion regarded as an electrical termination on the feeder line, an impedance matching resistor and an LC series resonance circuit that resonates at the frequency of the AC power are provided .
The feeder line is composed of a parallel line to which the AC power is supplied to the starting end, and the impedance matching resistor and the LC series resonance circuit are connected in parallel between the ends of the lines forming the parallel line. A power line carrier communication device.

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