JP4461538B2 - Power line carrier communication equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power line carrier communication apparatus that performs communication via a power feed line, and more particularly to a power line carrier communication apparatus applied to a non-contact power feeder that supplies power to a moving body such as a transport vehicle from the ground side in a contactless manner.
[0002]
[Prior art]
Conventionally, unmanned factories have been pushed forward 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. The power supply device includes a primary side circuit / feed line that is installed on the ground side and generates a high-frequency magnetic field, and a secondary side circuit that is mounted on the carrier and is magnetically coupled to the primary side feed line. The power is supplied in a non-contact state from the primary side to the secondary side circuit. 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]
FIG. 8 schematically shows a primary side 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 one track 20A and the other track 20B up to the folding point (termination Tb) are used as a pair of parallel tracks on a track 30 that is a traveling path of the carrier vehicle. It is attached. Further, the end portion of the feeder line 20 is connected to the high frequency power source 10, and high frequency currents having phases different by 180 degrees are supplied to the lines 20A and 20B, respectively.
[0005]
A ground-side communication transformer 40 of a communication device (not shown) installed on the ground side is magnetically coupled to the power supply line 20 near the high-frequency power supply 10. On the other hand, a transport vehicle-side communication transformer 50 magnetically coupled to the feeder 20 is mounted on the transport vehicle on the track 30, and a communication device (not shown) on the transport vehicle side passes through the communication transformer 50. Are connected to the feeder line 20.
Thus, the power line carrier communication device uses the power supply line of the non-contact power supply device as a transmission path for communication signals, and the power supply line includes communication between each communication device on the ground side and the carrier vehicle side. The transformer is magnetically coupled.
[0006]
According to this power line carrier communication device, when communication is performed between the ground side and the carrier vehicle side, the frequency component representing the logical value “0” and the frequency component representing the logical value “1” are transmitted via the communication transformer. The code is transmitted by superimposing it on the power component on the feeder line and combining these frequency components. Here, for example, the logical value “0” is associated with the lower order of the frequency of the order of several hundred kHz, and the logical value “1” is associated with the higher order frequency.
[0007]
[Problems to be solved by the invention]
Incidentally, the line length up to the turning point of the feed line 20 is in the vicinity one wavelength of approximately a quarter of the communication signal, a standing wave is generated by the communication signal on the power supply line 20, the region as a communication impossible in orbit There is a problem that occurs.
[0008]
This mechanism will be described with reference to FIG. 9 and FIG.
The feed line 20 shown in FIG. 8 forms a distributed constant circuit, and is equivalent to the short-circuited end Tb of the parallel line composed of the line 20A and the line 20B as shown in FIG. For this reason, reflection occurs at the end Tb, and when the line length between the start end Ta and the end Tb becomes approximately a quarter wavelength of the communication signal, a node (resonance point) is located near the start end Ta as shown in FIG. A standing wave of a communication signal (communication current) having As a result, as shown in FIG. 9, when the transport vehicle 100 is located in the vicinity of the starting end Ta, the transport vehicle 100 cannot receive a communication signal from the ground side.
[0009]
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 in a vacuum, but the propagation speed decreases inside the feeder line, so that 5 minutes It is shortened to about 3. As a result, depending on the setting of the frequency of the communication signal, when the line length between the start end Ta and the end Tb reaches about 100 m, a standing wave appears on the line, and the region where the power line carrier wave communication becomes impossible is on the orbit. Occurs.
[0010]
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.
[0011]
The present invention has been made in view of the above circumstances, and even if a standing wave due to a communication signal is present on a feeder line in power line carrier communication, communication between the carrier on the track and the ground side is possible. It is an object of the present invention to provide a power line carrier communication device that can be used on all the tracks.
[0012]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has the following configuration.
That is, according to the present invention, AC power is supplied to a power supply line (for example, a component corresponding to a power supply line 21 to be described later) attached to a track of a mobile body (for example, a component corresponding to a transport vehicle 100 to be described later). In a non-contact power supply device that performs non-contact power supply to a moving body, in a power line carrier communication device that performs communication between the ground side and the mobile body via the power supply line, magnetically coupled to the power supply line And a communication transformer (for example, a component corresponding to a ground-side communication transformer 41 described later) provided on the ground side is arranged at a substantially center between a start end and a terminal end of the feed line, Power line carrier communication is performed with a communication transformer (for example, a component corresponding to a carrier-side communication transformer 50 described later) that is magnetically coupled and mounted on the mobile body.
[0013]
According to this configuration, the ground-side communication transformer is positioned at the approximate center between the start and end of the feed line, so that the length of the feed line viewed from the ground-side communication transformer is equal to the total length of the feed line. Approximately half of the track length. For this reason, even if the line length of the feeder line (parallel line) is, for example, a quarter wavelength of the communication signal, the line length of the feeder line viewed from the ground-side communication transformer is less than the quarter wavelength of the communication signal. The effect of standing waves does not appear. In other words, according to this configuration, if the line length from the beginning to the end of the feeder line is less than a half wavelength of the communication signal, there is no resonance point of the standing wave on the feeder line, and the track Communication is possible in the entire area above.
[0014]
Further, the present invention supplies AC power to a power supply line (for example, a component corresponding to a power supply line 22 described later) attached to a track of a moving body (for example, a component corresponding to a transport vehicle 100 described later), and In a non-contact power supply device that performs non-contact power supply to a moving body, in a power line carrier communication device that performs communication between the ground side and the mobile body via the power supply line, magnetically coupled to the power supply line Two communication transformers (for example, constituent elements corresponding to ground side communication transformers 42A and 42B described later) are provided on the ground side, and are arranged on the start side and the end side of the feeder line, respectively. Power line carrier communication is performed with a communication transformer (for example, a component corresponding to a carrier-side communication transformer 50 described later) that is magnetically coupled to an electric wire and mounted on the moving body.
[0015]
According to this configuration, the two ground-side communication transformers are located on both ends of the feeder line (parallel line), respectively, so that the waveforms of the communication signals output from the respective communication transformers are superimposed. For this reason, even if the line length of the feeder line becomes a quarter wavelength of the communication signal and a standing wave appears, communication in a region where communication with one communication transformer is impossible is compensated with the other communication transformer. The effect of standing waves does not appear. That is, according to this configuration, if the line length of the feeder line is less than a half wavelength of the communication signal, a node (resonance point) of the standing wave does not appear on the line of the feeder line, and the orbit Communication is possible across the entire area.
[0016]
Furthermore, the line length of the feeder line is less than a half wavelength of a communication signal transmitted through the feeder line.
According to this configuration, there is no resonance point on the line of the feeder line with respect to the set frequency of the communication signal, and power line carrier communication is possible over the entire track. That is, even if the frequency of the communication signal is arbitrarily set, the power line carrier communication can be performed over the entire track by setting the line length of the feeder line to less than a half wavelength of the communication signal.
[0017]
Furthermore, a half wavelength of a communication signal transmitted through the feeder line is longer than a line length of the feeder line.
According to this configuration, there is no resonance point on the line of the feed line with respect to the set line length of the feed line, and power line communication is possible over the entire track. That is, even if the line length of the feeder line is arbitrarily set, the power line carrier communication can be performed over the entire track by making the half wavelength of the communication signal longer than the line length of the feeder line.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a non-contact power feeding apparatus according to an embodiment of the present invention will be described with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to a common element and the description is abbreviate | omitted suitably.
[0019]
<Embodiment 1>
FIG. 1 schematically 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 the first embodiment is applied.
In the figure, reference numeral 10 denotes a high-frequency power source that generates a high-frequency current. Reference numeral 21 denotes a feeder line that generates a magnetic field when a high-frequency current is supplied from the high-frequency power source 10. The feeder line 21 is folded in the vicinity of the middle to form a parallel line from the line 21A and the line 21B, and is attached to the track 30 that is a traveling path of a transport vehicle (not shown).
[0020]
That is, the starting end Ta of this parallel line is connected to the high frequency power supply 10, and the terminal end Tb is short-circuited to each other through a resistance of 0 ohm. Further, high-frequency currents having a phase difference of 180 degrees are respectively supplied from the high-frequency power source 10 to the lines 21A and 21B, and high-frequency currents in opposite directions are supplied. However, if the feeder line 21 is viewed as a single line, these currents are in phase.
[0021]
Further, a substantially central portion between the start end Ta and the end Tb of the line 21A and the line 21B is drawn out of the track 30, and a communication device (not shown) installed on the ground side is provided in the lead-out part. ) Of the ground side communication transformer 41 is magnetically coupled. That is, the ground-side communication transformer 41 is disposed at the approximate center of the feeder line 21. On the other hand, a conveyance vehicle (not shown) on the track 30 is equipped with a conveyance vehicle-side communication transformer 50 magnetically coupled to the power supply line 21, and a communication device (not shown) on the conveyance vehicle side is provided. The power supply line 21 is connected via the communication transformer 50.
[0022]
Here, as shown in FIG. 2A, the ground-side communication transformer 41 is magnetically coupled to these lines at the lead-out portions of the lines 21A and 21B. A current having a frequency corresponding to a communication signal is supplied to the primary side winding 41A of the ground side communication transformer 41, and currents in opposite directions are induced in the line 21A and the line 21B by this current.
[0023]
Further, as shown in FIG. 4B, the carrier-side communication transformer 50 is magnetically coupled to the feeder line 21 (lines 21A and 21B) attached to the track 30 and flows through the lines 21A and 21B. As a result, currents in the same direction are induced in the secondary winding 50A. The transport vehicle-side communication transformer 50 moves along the feed line 21 while being magnetically coupled to the feed line 21 as the transport vehicle moves.
[0024]
In the first embodiment, when the line length of the feeder line 21 is referred to, the line length of the parallel line made up of the line 21A and the line 21B is represented. When Ta represents the end of the feeder line 21, it represents the end Tb of the parallel line. Further, it is assumed that the line length of the feeder line 21 is approximately a quarter wavelength of the communication signal.
[0025]
Next, the operation of the power line carrier communication apparatus according to the first embodiment will be described with reference to FIG. 3 and FIG.
A high frequency current as power is supplied in advance from the high frequency power supply 10 to the power supply line 21, and a high frequency magnetic field is generated around the power supply line 21. Similarly to the above-described conventional technology, the communication between the ground side and the transport vehicle side uses the lower frequency component corresponding to the logical value “0” and the upper frequency component corresponding to the logical value “1” as power. It is performed by superimposing on.
[0026]
First, when sending a communication signal from the ground side to the transport vehicle 100 on the track 30, the ground side communication device outputs the communication signal to the feeder line 21 via the ground side communication transformer 41. As a result, the communication signal from the ground side is transmitted on the feeder line 21 while being superimposed on the waveform of the high-frequency current from the high-frequency power supply 10.
[0027]
Here, when viewed from the ground-side communication transformer 41, each line length from the starting end Ta and the terminating end Tb of the feeder line is approximately one-eighth wavelength of the communication signal, so that the reflection by the communication signal at the starting end Ta and the terminating end Tb. Even if the wave is generated, the node (resonance point) of the standing wave does not appear on the feeder line 21 as shown in FIG. Therefore, no matter where the transport vehicle 100 is located on the track 30, a communication signal is guided to the transport vehicle-side communication transformer 50 mounted on the transport vehicle 100, and a communication signal from the ground side can be received. .
[0028]
On the contrary, when a communication signal is transmitted from the transport vehicle 100 to the ground side, the line length between the transport vehicle 100 and the ground communication transformer 41 is always shorter than a quarter wavelength. For this reason, no standing wave node appears near the ground-side communication transformer 41. Accordingly, the communication device on the ground side can receive a communication signal from the transport vehicle regardless of where the transport vehicle is located on the track 30.
Therefore, there is no area incapable of communication on the entire track.
According to the first embodiment, communication on the entire track is possible without complicating the configuration of the apparatus.
[0029]
In the first embodiment, the line length of the feeder line 21 is set to a quarter wavelength of the communication signal. However, when viewed from the ground-side communication transformer 41, the line length from the starting end Ta to the terminal end Tb of the feeder line 21 is the communication length. Therefore, the length of the feeder line 21 (parallel line) can be arbitrarily set to less than a half wavelength of the communication signal. In other words, the half wavelength of the communication signal transmitted through the feeder line 21 only needs to be longer than the line length of the feeder line 21.
[0030]
<Embodiment 2>
Next, a second embodiment of the present invention will be described.
FIG. 5 schematically shows the configuration of the primary circuit of the non-contact power supply apparatus to which the power line carrier communication apparatus according to the second embodiment is applied. This non-contact power supply apparatus supplies AC power to a power supply line attached to the track on which the transport vehicle travels, and performs contact power supply to the transport vehicle on this track, as in the first embodiment. Is.
[0031]
In the figure, reference numeral 10 denotes a high-frequency power source that generates a high-frequency current, and reference numeral 22 denotes a feeder line that generates a magnetic field when the high-frequency current is supplied from the high-frequency power source 10. As in the first embodiment, the feeder line 22 is folded back near the middle thereof to form a parallel line from the line 22A and the line 22B, and is attached to the track 30.
[0032]
That is, the starting end Taa of the parallel line is connected to the high frequency power supply 10 and the terminal end Tbb is drawn out of the track 30 and short-circuited to each other. Further, high-frequency currents having a phase difference of 180 degrees are respectively supplied from the high-frequency power source 10 to the line 22A and the line 22B, and high-frequency currents in opposite directions are supplied to the line 22A and the line 22B. However, if the feeder line 21 is viewed as a single line, these currents are in phase.
[0033]
Reference numerals 42 </ b> A and 42 </ b> B denote ground-side communication transformers, which are arranged on the start end Taa side and the end Tbb side of the line 22 </ b> A and the line 22 </ b> B, respectively, and are magnetically coupled to the feeder line 22. That is, the two communication transformers 42A and 42B are provided on the ground side, and are disposed on the start end side and the end end side of the feeder line, respectively. These ground side communication transformers 42A and 42B are commonly supplied with a communication signal from a ground side communication device (not shown), and the ground side communication device is connected to the power supply line via the ground side communication transformers 42A and 42B. 22 is connected. The ground side communication transformers 42A and 42B have the same structure as the ground side communication transformer 41 shown in FIG.
In FIG. 5, reference numeral 50 denotes a transport vehicle side communication transformer provided in a communication device mounted on the transport vehicle, which is shown in FIG.
[0034]
In the second embodiment, the line length of the feeder line 22 refers to the line length of the parallel line composed of the line 22A and the line 22B, and the beginning end of the parallel line refers to the beginning end of the feeder line 22. When Taa is represented and the end of the feeder line 22 is referred to, it represents the end Tbb of the parallel line. Further, it is assumed that the line length of the feeder line 22 is approximately a quarter wavelength of the communication signal.
[0035]
The operation of the power line carrier communication apparatus according to the second embodiment will be described below with reference to FIGS.
It is assumed that a high frequency current as power is supplied in advance to the power supply line 22 from the high frequency power supply 10, and a high frequency magnetic field is generated around the power supply line 22. Similarly to the above-described conventional technology, the communication between the ground side and the transport vehicle side uses the lower frequency component corresponding to the logical value “0” and the upper frequency component corresponding to the logical value “1” as power. It is performed by superimposing on.
[0036]
First, when sending a communication signal from the ground side to the transport vehicle 100 on the track 30, the ground side communication device outputs the communication signal to the feeder line 22 via the ground side communication transformers 42A and 42B. As a result, the communication signal from the ground side is transmitted on the feeder line 22 while being superimposed on the waveform of the high-frequency current from the high-frequency power supply 10.
[0037]
At this time, as seen from the ground side communication transformer 42A installed on the start end Taa side, the line length to the end Tbb of the parallel line is approximately a quarter wavelength of the communication signal, so as shown in FIG. In addition, a standing wave node (resonance point) due to a communication signal (communication current) from the ground-side communication transformer 42A is generated near the starting end Taa where the ground-side communication transformer 42A is installed.
[0038]
On the other hand, as viewed from the ground side communication transformer 42B installed on the terminal Tbb side, the line length to the start end Taa of the parallel line is similarly about a quarter wavelength of the communication signal, and therefore, as shown in FIG. As described above, a standing wave node (resonance point) due to a communication signal (communication current) from the ground side communication transformer 42B is generated near the terminal Tbb where the ground side communication transformer 42B is installed.
[0039]
Here, standing waves by the respective communication signals from the ground side communication transformers 42 </ b> A and 42 </ b> B are combined on the feeder line 30. As a result, the node of one standing wave is supplemented by the other standing wave, and the node (resonance point) of the standing wave does not appear over the entire area of the feeder line 22 as shown in FIG. Accordingly, the transport vehicle 100 can receive a communication signal from the ground side regardless of where it is located on the track 30.
[0040]
In addition, considering the case where a communication signal is transmitted from the transport vehicle 100 to the ground side, a node of a standing wave due to the communication signal transmitted from the transport vehicle 100 exists on either side of the ground-side communication transformer 42A or 42B. However, since it does not exist on the other side, the communication signal from the transport vehicle is received by either the ground side communication transformer 42A or 42B. Therefore, the communication device on the ground side can receive a communication signal from the transport vehicle wherever the transport vehicle is located on the track 30. Therefore, there is no area incapable of communication on the entire track. According to the second embodiment, it is possible to cope with a line length of less than a half wavelength of a communication signal, and communication with a high SN ratio is possible on the entire track.
[0041]
In the second embodiment, the line length of the feeder line 22 is set to approximately a quarter wavelength of the communication signal. For example, when viewed from the ground-side communication transformer 42A, the line length to the terminal Tbb of the feeder line 22 is the communication signal. Therefore, the line length of the feeder line 22 can be arbitrarily set up to less than about half the wavelength of the communication signal. In other words, the half wavelength of the communication signal transmitted through the feeder line 22 only needs to be longer than the line length of the feeder line 22.
[0042]
Although one embodiment of the present invention has been described above, the present invention is not limited to the first and second embodiments described above, and the present invention can be applied even if there is a design change or the like without departing from the gist of the present invention. include. For example, in each of the embodiments described above, the line length of the feeder lines 20 and 21 is set to approximately a quarter wavelength of the communication signal. However, the present invention is not limited thereto, and is approximately a half wavelength of the communication signal. It is sufficient to set appropriately according to the trajectory length of the transport system.
[0043]
In the first embodiment described above, the ground communication transformer is installed in the approximate center of the feeder line 21. As a modification, a plurality of ground communication transformers are provided between the start end Ta and the end Tb. It is also possible to provide it. Thereby, the SN ratio of the communication signal can be improved.
Furthermore, the above-described Embodiment 1 and Embodiment 2 may be combined to install a ground-side communication transformer at the start end, the end, and the central portion of the feeder line. Thereby, an even better SN ratio can be obtained.
[0044]
【The invention's effect】
As described above, according to the present invention, the ground that is magnetically coupled to the feed line at the approximate center between the start and end of the feed line attached to the track, or at the start and end of the feed line. Since the side communication transformer is installed, no standing wave node appears over the entire area of the power supply line. Therefore, even when a standing wave due to a communication signal is present on the power supply line in power line carrier communication, Communication between the transport vehicle and the ground side is possible on the entire track.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a non-contact power feeding apparatus to which a power line carrier communication apparatus according to Embodiment 1 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 Embodiment 1 of the present invention;
FIG. 3 is a diagram for explaining the operation of the power line carrier communication apparatus according to Embodiment 1 of the present invention.
FIG. 4 is a diagram showing a waveform of a standing wave on a feeder line by the power line carrier communication apparatus according to Embodiment 1 of the present invention.
FIG. 5 is a diagram showing a configuration of a non-contact power feeding device to which a power line carrier communication device according to Embodiment 2 of the present invention is applied.
FIG. 6 is a diagram for explaining the operation of the power line carrier communication apparatus according to Embodiment 2 of the present invention.
FIG. 7 is a diagram showing a waveform of a standing wave on a feeder line by a power line carrier communication apparatus according to Embodiment 2 of the present invention.
FIG. 8 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. 9 is a diagram for explaining the operation of the power line carrier communication apparatus according to the prior art.
FIG. 10 is a diagram showing a waveform of a standing wave on a feeder line by a power line carrier communication apparatus according to a conventional technique.
[Explanation of symbols]
10: high frequency power supplies 21, 22: feeder lines 21A, 21B, 22A, 22B; lines (parallel lines)
30: Tracks 41, 42A, 42B; Ground side communication transformer 41A: Primary winding 50A of the ground side communication transformer; Secondary winding 50 of the carrier side communication transformer; Carrier side communication transformer 100; Taa; start end Tb, Tbb; end

Claims (3)

A non-contact power supply apparatus that supplies AC power to a power supply line attached to a trajectory of a mobile body to perform non-contact power supply to the mobile body, between the ground side and the mobile body via the power supply line In the power line carrier communication device that performs the communication of
A first communication transformer that is magnetically coupled to the power supply line and provided on the ground side is disposed at a substantially center between a start end and a terminal end of the power supply line, and is magnetically coupled to the power supply line. And configured to perform power line carrier communication by transmitting a communication signal via the feeder line between the second communication transformer and the first communication transformer mounted on the mobile body ,
The power line carrier communication device , wherein a line length of the feeder line is less than half of a wavelength of the communication signal . A non-contact power supply apparatus that supplies AC power to a power supply line attached to a trajectory of a mobile body to perform non-contact power supply to the mobile body, between the ground side and the mobile body via the power supply line In the power line carrier communication device that performs the communication of
Two first communication transformers that are magnetically coupled to the power supply line are provided on the ground side, and are arranged on a start side and a termination side of the power supply line, respectively, and are magnetically coupled to the power supply line. And configured to perform power line carrier communication by transmitting a communication signal via the feeder line between the second communication transformer and the first communication transformer mounted on the mobile body ,
The power line carrier communication device , wherein a line length of the feeder line is less than half of a wavelength of the communication signal .   A non-contact power supply apparatus that supplies AC power to a power supply line attached to a trajectory of a mobile body to perform non-contact power supply to the mobile body, between the ground side and the mobile body via the power supply line In the power line carrier communication device that performs the communication of
  A first communication transformer that is magnetically coupled to the power supply line and provided on the ground side is disposed at a substantially center between a start end and a terminal end of the power supply line, and is magnetically coupled to the power supply line. And configured to perform power line carrier communication by transmitting a communication signal via the feeder line between the second communication transformer and the first communication transformer mounted on the mobile body,
  The power line carrier communication apparatus characterized in that a line length from the start end to the end when viewed from the first communication transformer is less than a quarter of a wavelength of the communication signal.

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