Power line communication system

Abstract

To provide a power line carrier communication system that can achieve both cost reduction and availability maintenance.SOLUTION: A power line carrier communication system includes mutually exclusive first to third power supplies, first to third power lines, controllers, and first and second transmission devices. The controllers are connected to a light and the first to third power lines. The first and second transmission devices are connected to the first and second power lines, respectively, and generate messages. Each controller includes a communication unit, a power supply unit, and a control unit. The communication unit communicates with the first transmission device via the first power line, and communicates with the second transmission device via the second power line. The power supply unit generates drive power from power supplied from any two power lines of the first power line, the second power line, and the third power line. The control unit is supplied with drive power and controls the light based on a message acquired via the first power line or the second power line.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of this invention relate to a power line communication system.

Background Art

[0002] The lighting control system is essential for the safe operation of aircraft taking off and landing at airports. At airport fields, a wide variety of lights such as guiding lights and control lights are installed in large numbers on taxiways and guiding roads. In addition, a system for monitoring and lighting control of failure states such as broken cores of various guiding lights is also laid.

[0003] In many systems, the power line for supplying power to the lights also serves as a communication medium for monitoring and controlling the lights. This type of system is known as a power line communication system. The power line communication system is widely used in applications such as a stop line light system (STBL) that lights / extinguishes lights to guide an aircraft on the ground, or a runway status display lighting system (RWSL), or for detecting broken cores of lights.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Non-Patent Documents

[0005] [Non-Patent Document 1] "Current Status and Trends of Airport Lighting Systems", [online], [Retrieved November 22, 2021], Internet,<URL:https: / / www.jstage.jst.go.jp / article / ieiej / 37 / 2 / 37_79 / _pdf / -char / en> [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] To illuminate the lights installed on runways and taxiways, a vast number of cables are laid across the airport's extensive network. This leads to increased construction costs, including not only the cost of the cables themselves, but also civil engineering, piping, and cable laying. The longer the construction period, the greater the costs. Furthermore, cables must also be laid for the cable break detection system, adding even more expense.

[0007] On the other hand, ensuring a high level of system availability is desirable for the safe operation of aircraft. For example, to ensure that operations can continue even if one of the devices controlling the monitoring system fails, it is preferable to make the equipment and communication paths redundant. However, this leads to increased infrastructure costs.

[0008] Thus, in airport power line communication systems, there is a need to reduce equipment costs while maintaining a high level of availability. Technologies capable of satisfying these conflicting requirements are in demand. Therefore, the objective is to provide a power line communication system that can achieve both cost reduction and maintenance of availability, and contribute to the safe operation of aircraft. [Means for solving the problem]

[0009] According to the embodiment, the power line carrier communication system comprises a first power source, a second power source, and a third power source, all mutually exclusive; a first power line supplying power from the first power source; a second power line supplying power from the second power source; a third power line supplying power from the third power source; a plurality of controllers; and a first transmission device and a second transmission device. The controllers are connected to the lights and to the first power line, the second power line, and the third power line. The first transmission device is connected to the first power line and generates telegrams to control the lights. The second transmission device is connected to the second power line and generates telegrams. Each controller comprises a communication unit, a power supply unit, and a control unit. The communication unit communicates with the first transmission device via the first power line and with the second transmission device via the second power line. The power supply unit generates driving power from power supplied from any two of the first, second, and third power lines. The control unit includes a control unit that is supplied with driving power and controls the lights based on a message obtained via a first power line or a second power line. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 shows an example of a power line carrier communication system according to the embodiment. [Figure 2] Figure 2 shows an example of the connection between the transmission devices 103 and 109, the controller 104, and the sensor 106. [Figure 3] Figure 3 is a functional block diagram showing an example of the transmission device 103. [Figure 4] Figure 4 shows an example of a logical network topology between a transmission device and a controller. [Figure 5] Figure 5 is a functional block diagram showing an example of the controller 104. [Figure 6] Figure 6 is a functional block diagram showing another example of the controller 104. [Figure 7] Figure 7 shows another example of a logical network topology between a transmission device and a controller. [Figure 8] Figure 8 is a diagram illustrating the relationship between network topology and transmission delay. [Figure 9]FIG. 9 is a diagram for explaining the relationship between network topology and transmission delay. [Figure 10] FIG. 10 is a diagram for explaining priority control.

Embodiment for Carrying out the Invention

[0011] FIG. 1 is a diagram showing an example of a power line communication system according to an embodiment. The system of FIG. 1 includes an operation console 100, a controller 101, a data processing device 102, transmission devices 103 and 109, a controller 104, a lamp 105, various sensors 106, a power supply 107, a transmission line 108, and a power line 110. Among these, the operation console 100, the controller 101, and the data processing device 102 are placed in a central facility such as an air traffic control tower, and the transmission devices 103 and 109, the controller 104, the lamp 105, various sensors 106, and the power supply 107 are arranged in a field such as a remote runway or a taxiway.

[0012] The operation console 100 displays information related to the monitoring and control of the lamp 105 (such as control commands, status, or abnormal information). These information are aggregated by the controller 101, processed, and the organized information is passed to the data processing device 102. The data processing device 102 transmits various telegrams to the transmission devices 103 and 109 in the field via the transmission line 108.

[0013] Here, the transmission devices 103 and 109, the controller 104, the sensors 106, the power line 110, and the power supply 107 are each duplicated and have a redundant configuration. The transmission devices 103 and 109, the controller 104, the lamp 105, and the sensors 106 receive power supply from the power supply 107 via the power line 110. The transmission devices 103 and 109 transmit telegrams to the subordinate controller 104 by power line communication via the power line 110. The controller 104 receives the telegram transmitted from the transmission device 103 in the downlink and controls the lighting / extinguishing / flashing of the lamp 105. Also, the controller 104 transmits the data acquired by the sensors 106 to the transmission device 103 in the uplink.

[0014] In this embodiment, a three-phase AC power supply is assumed as the power supply 107. Each phase of the three-phase AC is designated as phase A, phase B, and phase C, and the power supply systems for each phase are designated as power supply system A, system B, and system C. The AC power from each system is supplied to the redundant transmission devices 103 and 109 in an mutually exclusive manner. In other words, power supply system A as the first power supply, power supply system B as the second power supply, and power supply system C as the third power supply are mutually exclusive. By connecting the power lines of different systems to the controller 104 under the transmission devices 103 and 109, the power supply system can be duplicated, and power line communication can also be implemented.

[0015] The controller 104 is powered by a power source separate from the higher-level transmission device (103 or 109). The lights 105 are arranged in an alternating pattern so that no adjacent lights powered by the same power source are adjacent to each other. In other words, the lights 105, arranged in a staggered pattern on the lighting line, receive power from different power supply systems. Thus, the lights 105 are redundant by being arranged in an alternating pattern on the same lighting line and utilizing different power supply systems.

[0016] Figure 2 shows an example of the connection of transmission devices 103, 109, controller 104, and sensor 106 on the field side. In Figure 2, transmission device 103 is equipped with transmission devices 1-1 and 1-2 and functions as a single system. Similarly, transmission device 109 is equipped with transmission devices 2-1 and 2-2 and functions as a double system.

[0017] In system 1, transmission device 1-1 is connected to power supply system A, and transmission device 1-2 is connected to power supply system B. Controllers 1-1, 1-2, ..., 1-n under system 1 are connected to power supply systems A, B, and C. Similarly, in system 2, transmission device 2-1 is connected to power supply system A, and transmission device 2-2 is connected to power supply system B. Controllers 2-1, 2-2, ..., 2-n under system 2 are connected to power supply systems A, B, and C.

[0018] The power line 110 includes a first power line supplying power from power source A, a second power line supplying power from power source B, and a third power line supplying power from power source C. Here, transmission devices 1-1 and 2-1 are connected to the first power line and generate telegrams to control the lights 105. Transmission devices 1-2 and 2-2 are connected to the second power line and generate telegrams to control the lights 105.

[0019] For example, by configuring transmission devices connected to STBL or TCLL, which are controlled at the same timing, with two separate circuits, operation can continue even if an abnormality occurs in one of the systems. The controller 104 is connected to the lights 105 and the first, second, and third power lines.

[0020] As shown in Figure 2, the controller 104 is powered by three power sources, and two of these sources (for example, systems A and B) are individually connected to the transmission equipment of each system, thereby duplicating both the power supply and power line communication.

[0021] Figure 3 is a functional block diagram showing an example of a transmission device 103. The configuration of the transmission device 109 is similar. The transmission device 103 includes redundant transmission devices 1-1 and 1-2, each of which comprises a power supply unit 200, an upper transmission unit 201, a processing unit 202, and a lower transmission unit 203.

[0022] In transmission device 1-1, the power supply unit 200 is connected to power supply system A, and the power supply unit 200 supplies A-phase power to the upper transmission unit 201, the processing unit 202, and the lower transmission unit 203. The upper transmission unit 201 communicates with the data processing unit 102 (Figure 1) via power line communication through transmission system A of the transmission line 108. The processing unit 202 controls the lights 105 and processes monitoring data from the sensor 106. The lower transmission unit 203 communicates with the lower controllers 1-1, 1-2, ..., 1-n via power line communication through power system A.

[0023] In the transmission device 1-2, the power supply unit 200 is connected to the power supply B system, and the power supply unit 200 supplies B-phase power to the upper transmission unit 201, the processing unit 202, and the lower transmission unit 203. The upper transmission unit 201 communicates with the data processing unit 102 via power line communication through the transmission B system of the transmission line 108. The processing unit 202 controls the lights 105 and processes monitoring data from the sensor 106. The lower transmission unit 203 communicates with the controllers 1-1, 1-2, ..., 1-n via power line communication through the power supply B system. Incidentally, the lower-level transmission unit 203 forms a multi-hop network topology between the transmission device and the controllers under its control.

[0024] Figure 4 shows an example of a logical network topology between a transmission device and a controller. As shown in (a) to (d), depending on factors such as the arrangement of the controller 104, the branching of the transmission path 108, and the transmission distance, the lower-level transmission unit 203 forms different network topologies between the transmission device and the controller. Multi-hopping can improve the reliability of information delivery from the transmission device to each controller, even when extending the transmission distance.

[0025] Figure 5 is a functional block diagram showing an example of a controller 104. The controller 104 comprises a power supply unit 300, a lower-level transmission unit 301, a processing unit 302, and a control unit 303. The power supply unit 300 is connected to power supply systems A, B, and C, and supplies power from any of these systems as driving power to the lower-level transmission unit 301, the processing unit 302, and the control unit 303. In other words, the power supply unit 300 generates driving power from power supplied from any two of the first, second, and third power lines.

[0026] In other words, the controller 104 can receive power from multiple power sources. The lower transmission unit 301 is connected to power source A and power source B, and can perform power line communication using each system. Specifically, the lower transmission unit communicates with the first transmission device (transmission devices 1-1, 2-1) via the first power line 301, and with the second transmission device (transmission devices 1-2, 2-2) via the second power line. The power source for system C is internally logically OR connected to systems A and B in the power supply unit 300 so that it can be used in common between circuits even if the circuits are different.

[0027] The processing unit 302 extracts control information from a message obtained via power line communication from a higher-level transmission device. The control unit 303 is connected to the lamp 105 and controls the lamp 105 based on the extracted control information, and also responds to the transmission device via the lower-level transmission unit 301 regarding whether or not there is a malfunction in the lamp 105. In other words, the control unit 303 controls the lamp 105 based on the drive power supplied from the power supply unit 300 and the message obtained via the first power line or the second power line.

[0028] In Figure 5, a redundant configuration consisting of power supply systems A and B is sufficient. However, if either power supply system A or B actually fails, the remaining system alone will have to supply power to all of the high-power lighting fixtures 105. To prepare for this, it will be necessary to secure a power source with more than double the capacity of normal operation, which raises concerns about the impact on equipment costs.

[0029] Therefore, in this embodiment, a third three-phase AC power supply system, power supply system C, is connected to the power supply unit 300 of the controller 104, and load balancing is performed by power supply system C. In other words, if either power supply system A or power supply system B fails, power can be supplied from power supply system C, thereby leveling the power capacity even in the event of an emergency. Consequently, the capacity of the backup power source can be kept to the minimum necessary, thus minimizing the impact on equipment costs.

[0030] Figure 6 is a functional block diagram showing another example of the controller 104. The controller 104 shown in Figure 6 includes, in addition to the configuration in Figure 5, a bridge 306 that connects the lower transmission unit 301 to the power supply C system of the third power line. Since the power supply C system is not interconnected with the transmission device 103, the bridge 306 allows for the transmission of messages via the power supply C system by switching, for example, from system A to system C, or from system B to system C.

[0031] Figure 7 shows another example of a logical network topology between a transmission device and a controller. As shown in Figure 7, different network topologies can be formed with different power systems, making it possible to select an efficient transmission path with respect to the communication path that depends on the communication environment. For example, it is possible to reduce the number of hops in the communication path and improve the reliability and speed of message delivery. In Figure 7, it is shown that controller 1-1 of system B is bridged to system C. Note that the bridging function may be included in the lower transmission unit 203.

[0032] Incidentally, the transmission route of the message in this embodiment is a multi-hop route under an arbitrary network topology with redundant transmission devices (103, 109) as the route. Therefore, it is expected that the time it takes for the message to arrive from the transmission device will increase as the number of hops increases.

[0033] Figures 8 and 9 illustrate the relationship between network topology and transmission delay. As shown in Figure 8, as the number of hops increases (A, B, C, D), the time it takes for a message sent from the transmission device to reach the controller increases. This is undesirable in lighting control, where precise synchronization of on / off or flashing timing is required. In other words, in lighting control, multiple circuits must be controlled simultaneously with a single control, so when data is sent and received between the transmission device and controller for each circuit, it becomes a problem if the control information arrives at each controller at different times.

[0034] Since control information affects, for example, the timing of turning lights on and off, there is a possibility that the variation in on / off times will increase to a degree that is visible to aircraft pilots, requiring countermeasures. Therefore, in this embodiment, the transmission devices 103 and 109 pre-determine the number of hops to the controller and the response time (transmission delay) with each controller 104, and store the relationship between the number of hops and the time difference in memory. Then, by including the time difference in the control command or the parameters of controller 104, the control timing of the other controllers is delayed to match the arrival time to the controller furthest away in terms of the number of hops (the fourth stage in Figure 8).

[0035] In other words, the controllers from the first to the third stage use counters or timers to delay the control timing by a time difference of ΔtA to ΔtC from the arrival of the control command (telegram). Here, ΔtA=DA, ΔtB=DB, and ΔtC=DC (A, B, C, and D are the arrival times of the telegrams up to each stage). By doing this, it becomes possible to synchronize the control timing of the controllers from the first to the fourth stage. This helps to suppress variations in the on / off of lights as seen by the aircraft pilot.

[0036] Furthermore, due to the afterimage phenomenon, variations are not visible if kept short. Therefore, time differences within a certain period can be ignored. For example, as shown in Figure 9, if the time difference (transmission delay) from ΔtA to ΔtC is within a threshold (e.g., a few ms), this time difference can be ignored. Therefore, the lights can be controlled at the time the control command arrives, without using delay means such as counters or timers. In other words, the control timing should be delayed only when the transmission delay exceeds a predetermined threshold.

[0037] Alternatively, as shown in Figure 9, the controllers may be divided into several groups based on the time difference (transmission delay), and a control delay time may be set for each group. In this way, it is possible to avoid assigning complex parameters to control commands and controller 104, and to achieve synchronized control of the lights with simple processing.

[0038] Figure 10 is a diagram illustrating priority control. By providing a bridge 306 (Figure 6) to the controller 104, it is possible to set up an uplink and a downlink in the transmission path of power line carrier communication using different power sources. Furthermore, priorities can be set for each link. For example, communication traffic on the uplink from the controller to the transmission device can be given a higher priority than communication traffic on the downlink in the opposite direction. With such settings, for example, the underlying information necessary for control, such as sensor data, can be preferentially aggregated on the uplink to the higher-level device. Furthermore, response information such as the on / off status of the controller and any abnormalities can be transmitted using a near full-duplex method for both downstream and upstream connections, making it possible to guarantee response times.

[0039] As described above, according to the embodiment, it is possible to provide a power line communication system that can achieve both cost reduction and maintenance of availability, contributing to the safe operation of aircraft. Furthermore, it is possible to provide a power line communication system that can achieve different performance requirements for monitoring and control using multiple different power lines within the airport field, while suppressing cable installation costs.

[0040] While embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications are permitted without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, as well as within the scope of the claims and their equivalents. [Explanation of symbols]

[0041] 100...Operation console, 101...Controller, 102...Data processing unit, 103...Transmission device, 104...Controller, 105...Lighting, 106...Sensor, 107...Power supply, 108...Transmission line, 109...Transmission device, 110...Power line, 200...Power supply unit, 201...Higher transmission unit, 202...Processing unit, 203...Lower transmission unit, 300...Power supply unit, 301...Lower transmission unit, 302...Processing unit, 303...Control unit, 306...Bridge.

Claims

1. The first, second, and third power supplies are mutually exclusive, A first power line supplying power from the first power source, a second power line supplying power from the second power source, and a third power line supplying power from the third power source, A light fixture, and a plurality of controllers connected to the first power line, the second power line, and the third power line, A first transmission device connected to the first power line and generating a telegram for controlling the lights, The system comprises a second transmission device connected to the second power line and for generating the message, Each of the aforementioned controllers is: A communication unit that communicates with the first transmission device via the first power line and with the second transmission device via the second power line, A power supply unit that generates driving power from power supplied from any two of the aforementioned power lines, the first power line, the second power line, and the third power line, A power line carrier communication system comprising: a control unit that is supplied with the aforementioned driving power and controls the lights based on a telegram obtained via the first power line or the second power line.

2. Each of the controllers further comprises a bridge that bridges the communication unit to the third power line, The power line carrier communication system according to claim 1, wherein the control unit forms a first network in a first network topology with the first transmission device as the root, and a second network in a second network topology with the second transmission device as the root.

3. The power line carrier communication system according to claim 2, wherein each of the controllers delays the control timing and synchronizes the control of the lights based on the transmission delay from the route under the first network topology and the transmission delay from the route under the second network topology.

4. The power line carrier communication system according to claim 3, wherein each of the controllers delays the control timing to synchronize the control of the lights when the transmission delay exceeds a predetermined threshold.

5. The power line carrier communication system according to claim 3, wherein each of the controllers delays the control timing by a certain amount for each of the plurality of groups based on the transmission delay.

6. The power line carrier communication system according to claim 1, wherein the communication unit sets different priorities for the communication traffic via the first power line and the communication traffic via the second power line.

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