Control device and control method for optical node

Abstract

This control device and control method for an optical node involve a controller that controls an optical node. The optical node comprises: a photoelectric conversion element that receives power-feeding light transmitted via an optical fiber and converts the power-feeding light into power; a power storage element that stores the power; a temperature sensor that measures the temperature of an environment including the optical node; and a communication unit that transmits temperature information indicating the temperature. The controller acquires temperature information via the communication unit, refers to a database in which characteristic information of the power storage element is recorded, acquires characteristic information associated with temperature, and estimates the voltage of the power storage element on the basis of an equivalent circuit model of the power storage element established using the characteristic information.

Description

Optical node control device and control method

[0001] The present disclosure relates to a control device and a control method for an optical node.

[0002] Non-Patent Document 1 discloses a technology for powering optical nodes with light passing through an optical fiber in an optical node system in which multiple optical nodes each equipped with multiple power storage elements are connected in series to a single optical fiber. According to this technology, a determination is periodically made as to whether the voltage of the power storage element estimated by an internal microcontroller is equal to or greater than a predetermined threshold, and the power supply destination via the optical fiber is switched between the local and other optical nodes based on the determination result.

[0003] T. Kawano, T. Manabe, A. Kuroda, K. Nakae,H. Watanabe1, K. Katayama, “Control using Power-over-Fiber for Remote-Operated Optical Fiber Switching Nodes”, Proceedings of the IWCS 2022 Cable & Connectivity Symposium, Oct. 2022.

[0004] According to the technology described in Non-Patent Document 1, when the ambient temperature including the optical node fluctuates, the characteristics of the storage elements included in the optical node change, and there is a problem that the voltage of the storage elements cannot be estimated accurately.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a control device and a control method for an optical node that can accurately estimate the voltage of a storage element, etc., included in the optical node, taking into account changes in the characteristics of the storage element, etc., included in the optical node, even when the ambient temperature including the optical node fluctuates.

[0006] In order to solve the above-mentioned problems, the present disclosure provides a control device and control method for an optical node, and relates to a controller for controlling an optical node. The optical node includes a photoelectric conversion element that receives power supply light transmitted through an optical fiber and converts it into electric power, a storage element that stores the electric power, a temperature sensor that measures the temperature of an environment including the optical node, and a communication unit that transmits temperature information indicating the temperature. The controller acquires the temperature information via the communication unit, refers to a database that records characteristic information of the storage element, acquires characteristic information associated with the temperature, and estimates the voltage of the storage element based on an equivalent circuit model of the storage element defined by the characteristic information.

[0007] According to the present disclosure, even if the ambient temperature including the optical node fluctuates, the voltage of the storage element can be accurately estimated by taking into account changes in the characteristics of the storage element and the like included in the optical node.

[0008] It is a diagram showing a configuration of an optical power supply system including a control device according to an embodiment of the present disclosure. It is a diagram showing an equivalent circuit when a storage element is being charged. It is a diagram showing an equivalent circuit when a storage element is being discharged. It is a flowchart showing an example of processing by a control device when controlling a plurality of optical nodes.

[0009] Next, embodiments of the present disclosure will be described in detail with reference to the drawings. In the description, the same components are designated by the same reference numerals and redundant description will be omitted.

[0010] [Configuration of Optical Power Supply System] Fig. 1 is a diagram illustrating the configuration of an optical power supply system including a control device according to an embodiment of the present disclosure. The optical power supply system includes a control device N0 and an optical node N1. Note that the optical power supply system may include optical nodes (optical nodes N2, N3, ...) in addition to the optical node N1. The control device N0 is connected to the optical nodes (optical nodes N1, N2, ...) included in the optical power supply system via an optical fiber FB, and the control device N0 manages the optical nodes included in the optical power supply system. In the following description, it is assumed that the optical nodes included in the optical power supply system have the same structure.

[0011] The optical node N1 includes a photoelectric conversion element PVC, a power storage element CP, a temperature sensor SC, and a communication unit OSM. The optical node N1 may also include an optical switch TR, an optical circulator CR1, a switch SW, a controller MPU, and a DC-DC converter DCV.

[0012] The photoelectric conversion element PVC receives the power supply light transmitted through the optical fiber FB and converts it into electric power. Here, the power supply light may be output from the control device N0. The photoelectric conversion element PVC may also receive the communication light transmitted through the optical fiber FB and convert it into a signal. The signal obtained by the photoelectric conversion element PVC may be transmitted to the controller MPU.

[0013] For example, the photoelectric conversion element PVC may be a photodiode, a phototransistor, a light-emitting diode, etc. An element suitable for receiving light in the long wavelength band of 1300 nm to 1600 nm for communication may be used as the photoelectric conversion element PVC. The photoelectric conversion element PVC is not limited to the examples given here.

[0014] The storage element CP stores the power obtained by the photoelectric conversion element PVC. For example, the storage element CP is an electric double layer capacitor. Alternatively, the storage element CP may be a battery. The storage element CP may be various types of batteries, such as a lithium ion battery or a zinc battery. The storage element CP is not limited to the examples given here.

[0015] The temperature sensor SC measures the temperature of the environment including the optical node. The temperature sensor SC shown in FIG. 1 measures the temperature of the environment including the optical node N1. For example, the temperature sensor SC is a thermistor. Note that the temperature sensor SC that measures the temperature of the environment including the optical node N1 does not necessarily have to be provided inside the optical node N1. The temperature sensor SC may be provided near the surface of the optical node N1, or may be located outside the optical node N1 and in the vicinity of the optical node N1. The temperature sensor SC is not limited to the examples given here.

[0016] The communication unit OSM transmits temperature information indicating the temperature obtained by the temperature sensor SC. For example, the temperature information is transmitted to the control device N0 by communication light transmitted through the optical fiber FB.

[0017] 1, temperature information is transmitted from the temperature sensor SC to a controller MPU (described later). The temperature information is then transmitted from the controller MPU to a communication unit OSM, and the temperature information is then transmitted to the control device N0 via the communication unit OSM by communication light transmitted through the optical fiber FB.

[0018] The communication unit OSM may be a unit that modulates the communication light and superimposes predetermined information on the communication light. The communication unit OSM is not limited to the example given here.

[0019] The controller MPU performs various processes based on signals contained in the communication light transmitted through the optical fiber FB. The controller MPU is driven by power from the power storage element CP.

[0020] The controller MPU may transmit control signals to the switch SW, the optical switch TR, and the communication unit OSM. The controller MPU may also receive signals from the photoelectric conversion element PVC, or may receive signals indicating temperature information from the temperature sensor SC. Additionally, the controller MPU may control various devices (not shown) mounted on the optical node N1.

[0021] For example, the controller MPU is a general-purpose computer equipped with a CPU (Central Processing Unit), memory, and input / output units. A computer program (control program) for controlling each unit of the optical node N1 is installed in the computer. Various functions are realized by executing the computer program.

[0022] The switch SW switches the storage element CP between a first state in which power obtained by the photoelectric conversion element PVC is supplied to the storage element CP and a second state in which power is not supplied to the storage element CP. For example, the switch SW switches between the first state and the second state based on a signal from the controller MPU. The switching by the switch SW is controlled based on the voltage of the storage element CP.

[0023] The controller MPU itself may monitor the voltage of the storage element CP and switch between the first and second states via the switch SW, but in order to increase the charging speed of the storage element CP in the optical node N1, it is desirable that the processing load on the controller MPU be small.

[0024] Therefore, the controller MPU may control the switch SW based on a command from the control device N0. The control device N0 may estimate the voltage of the storage element CP, and based on whether the estimated voltage is equal to or greater than a predetermined threshold, a control signal for the switch SW may be transmitted from the control device N0 to the optical node N1.

[0025] The optical switch TR is connected to the optical fiber FB and switches whether or not to guide the light transmitted from the control device N0 via the optical fiber FB to the optical circulator CR1. For example, the optical switch TR is a 1×2 optical switch. If the transmitted light is not to be guided to the optical circulator CR1, the optical switch TR may be configured to guide the transmitted light to optical nodes (optical nodes N2, N3, ...) subsequent to the optical node N1.

[0026] The optical circulator CR1 is connected to the optical switch TR, the photoelectric conversion element PVC, and the communication unit OSM. The optical circulator CR1 guides light from the optical switch TR to the photoelectric conversion element PVC. The optical circulator CR1 guides light from the communication unit OSM to the optical switch TR.

[0027] The DC-DC converter DCV boosts the power supplied from the power storage element CP and supplies the boosted power. For example, the DC-DC converter DCV supplies the boosted power to the communication unit OSM and the temperature sensor SC. In addition, the DC-DC converter DCV may supply the boosted power to various devices mounted on the optical node N1.

[0028] The control device N0 includes a controller CTL that controls the optical nodes (optical nodes N1, N2, ...). In addition, the control device N0 may include a database DB, a laser LD, a modulator FQ, an optical circulator CR0, and an optical receiver PD.

[0029] The laser LD outputs power supply light to be supplied to the optical nodes (optical nodes N1, N2, ...). For example, the laser LD is a semiconductor laser. Examples of semiconductor lasers include a Fabry-Perot laser (FP laser) and a distributed feedback laser (DFB laser). The laser LD is not limited to the examples given here.

[0030] The modulator FQ modulates the power supply light and superimposes the communication light on the power supply light. The modulator FQ may modulate the power supply light based on a signal received from the controller CTL and superimpose the communication light on the power supply light. For example, the modulator FQ is an electro-optic modulator, an acousto-optic modulator, a semiconductor optical modulator, or the like. The modulator FQ is not limited to the examples given here.

[0031] The optical circulator CR0 is connected to the modulator FQ, the optical receiver PD, and the optical fiber FB. The optical circulator CR0 guides the light from the modulator FQ to the optical fiber FB. The optical circulator CR0 guides the light from the optical fiber FB to the optical receiver PD.

[0032] The optical receiver PD may receive communication light transmitted through the optical fiber FB and convert it into a signal. The signal obtained by the optical receiver PD may be transmitted to the controller CTL.

[0033] For example, the optical receiver PD may be a photodiode, a phototransistor, a light-emitting diode, etc. An element suitable for receiving light in the long wavelength band of 1300 nm to 1600 nm for communication may be used as the optical receiver PD. The optical receiver PD is not limited to the examples given here.

[0034] The database DB records characteristic information of the power storage element CP. The database DB records the characteristic information for each temperature of the environment including the optical node.

[0035] Here, the "characteristic information" refers to the characteristics of the storage element CP and other elements that constitute the optical node. For example, the "characteristic information" refers to the capacitance C of the storage element CP, the equivalent series resistance R ＥＳＲ , and the leakage resistance component R ｌｅａｋ In addition, the "characteristic information" includes the series resistance component R ＭＰＵ , and the sleep current I ＣＣ , and may include the output current I of the photoelectric conversion element.

[0036] The controller CTL performs various processes based on signals contained in the communication light transmitted through the optical fiber FB. In particular, the controller CTL may control one or more optical nodes (optical nodes N1, N2, ...).

[0037] The controller CTL may transmit control signals to the laser LD and the modulator FQ. The controller CTL may also receive signals from the optical receiver PD. Additionally, the controller CTL may control various devices (not shown) mounted on the control device N0.

[0038] For example, the controller CTL is a general-purpose computer equipped with a CPU (Central Processing Unit), a memory, and an input / output unit. A computer program (control program) for controlling each unit of the control device N0 is installed in the computer. Various functions are realized by executing the computer program.

[0039] For example, the controller CTL may acquire temperature information transmitted from the communication unit OSM via the optical fiber FB. More specifically, the temperature information is transmitted as communication light via the communication unit OSM and converted into a signal by the optical receiver PD. The temperature information is then input from the optical receiver PD to the controller CTL.

[0040] The controller CTL may also refer to a database DB that records characteristic information of the power storage elements CP, and acquire characteristic information associated with the temperature of the environment including the optical node. That is, the controller CTL searches for characteristic information stored in the database DB based on the temperature measured by the temperature sensor SC, and acquires the characteristics of the power storage elements CP and the like in the optical node.

[0041] Then, the controller CTL calculates the voltage V of the storage element CP based on the equivalent circuit model of the storage element CP determined by the characteristic information. Ｃ Estimate.

[0042] For example, Fig. 2 is a diagram showing an equivalent circuit when the storage element is being charged. Based on the equivalent circuit shown in Fig. 2, the voltage V of the storage element CP per unit time is Ｃ The change in dV Ｃ / dt can be written as follows using characteristic information:

[0043] 3 is a diagram showing an equivalent circuit when the storage element is discharging. Based on the equivalent circuit shown in FIG. 3, the voltage V of the storage element CP per unit time is Ｃ The change in dV Ｃ / dt can be written as follows using characteristic information:

[0044] Voltage V of the storage element CP per unit time Ｃ The change in dV Ｃ By integrating / dt over time, the voltage V of the storage element CP at a predetermined timing is calculated. Ｃ can be estimated.

[0045] The time integration method used by the controller CTL may be the Euler method or the Runge-Kutta method, but is not limited to the examples given here.

[0046] In addition, when the estimated voltage of the storage element CP is less than a predetermined threshold, the controller CTL may change the storage element CP to a first state in which power is supplied to the storage element CP via a switch SW or an optical switch TR.

[0047] In addition, when the estimated voltage of the storage element CP is equal to or higher than a predetermined threshold, the controller CTL may change the storage element CP to a second state in which no power is supplied to the storage element CP via the switch SW or the optical switch TR.

[0048] More specifically, the controller CTL may transmit a signal for controlling the switch SW or the optical switch TR to the optical node by communication light via the optical fiber FB. The controller MPU, which receives the signal, may control the switch SW or the optical switch TR to change the state of the power storage element CP.

[0049] 4 is a flowchart showing an example of processing by the control device when controlling a plurality of optical nodes. As an example, consider a case where the optical nodes included in the optical power supply system are optical nodes N1 and N2.

[0050] In step S101, the controller CTL transmits a predetermined control signal via the optical fiber FB to switch the optical path to the optical node N1. Specifically, the controller CTL establishes an optical path via the optical fiber FB to enable communication between the controller MPUs of the optical nodes N1.

[0051] In step S103, the controller CTL acquires the temperature information of the optical node N1.

[0052] In step S105, power supply to the optical node N1 is started. More specifically, the controller CTL controls the controller MPU and the switch SW to start charging the power storage element CP.

[0053] In step S107, the controller CTL estimates the voltage at the optical node N1. More specifically, based on the acquired temperature information, it acquires characteristic information of elements included in the optical node N1. Then, based on an equivalent circuit model of the storage element CP determined by the acquired characteristic information, it estimates the voltage V Ｃ Estimate.

[0054] In step S109, the controller CTL determines whether the voltage at the optical node N1 is equal to or greater than a predetermined threshold. Ｃ is equal to or greater than a predetermined threshold.

[0055] If it is determined that the difference is less than the predetermined threshold (NO in step S109), the process returns to step S107.

[0056] If it is determined that the difference is equal to or greater than the predetermined threshold (YES in step S109), in step S111, the controller CTL transmits a predetermined control signal via the optical fiber FB to switch the optical path to the optical node N2. Specifically, the controller CTL establishes an optical path via the optical fiber FB in a state in which communication is possible between the controller MPUs of the optical nodes N2.

[0057] In step S113, the controller CTL acquires the temperature information of the optical node N2.

[0058] In step S115, power supply to the optical node N2 is started. More specifically, the controller CTL controls the controller MPU and the switch SW to start charging the power storage element CP.

[0059] In step S117, the controller CTL estimates the voltages at the optical nodes N1 and N2. More specifically, based on the acquired temperature information, it acquires characteristic information of the elements included in the optical nodes N1 and N2. Then, based on an equivalent circuit model of the storage element CP determined by the acquired characteristic information, it estimates the voltage V Ｃ Estimate.

[0060] In step S119, the controller CTL determines whether the voltage at the optical node N1 is equal to or greater than a predetermined threshold. Ｃ is equal to or greater than a predetermined threshold.

[0061] If it is determined that the difference is less than the predetermined threshold (NO in step S119), the process returns to step S101.

[0062] If it is determined that the voltage is equal to or greater than the predetermined threshold (YES in step S119), in step S121, the controller CTL determines whether the voltage at the optical node N2 is equal to or greater than the predetermined threshold. Ｃ is equal to or greater than a predetermined threshold.

[0063] If it is determined that the difference is less than the predetermined threshold (NO in step S121), the process returns to step S117.

[0064] If it is determined that the value is equal to or greater than the predetermined threshold value (YES in step S121), the process shown in FIG. 4 ends.

[0065] [Effects of the Embodiments] As described in detail above, the optical node control device and control method according to the present disclosure relate to a controller for controlling an optical node. The optical node includes a photoelectric conversion element that receives power supply light transmitted through an optical fiber and converts it into electric power, a storage element that stores the electric power, a temperature sensor that measures the temperature of an environment including the optical node, and a communication unit that transmits temperature information indicating the temperature. The controller acquires the temperature information via the communication unit, refers to a database that records characteristic information of the storage element, acquires characteristic information associated with the temperature, and estimates the voltage of the storage element based on an equivalent circuit model of the storage element defined by the characteristic information.

[0066] As a result, even if the ambient temperature including the optical node fluctuates, the voltage of the storage element can be accurately estimated taking into account changes in the characteristics of the storage element and the like included in the optical node. In particular, by estimating the voltage of the storage element by a controller external to the optical node, power consumption within the optical node can be reduced. For example, since there is no need for the control device to directly inquire about the voltage to the optical node, power consumption in the optical node can be reduced. In addition, the charging speed of the storage element in the optical node can be increased. As a result, the efficiency of power supply to the optical node can be improved.

[0067] In addition, it is possible to schedule the appropriate timing for switching the power supply destination, thereby avoiding the risk of the voltage of the storage element falling outside the operating voltage range.

[0068] In the optical node control device and control method according to the present disclosure, the optical node may further include a switch that switches the energy storage element between a first state in which power is supplied to the energy storage element and a second state in which power is not supplied to the energy storage element. The controller may also change the energy storage element to the first state via the switch when the voltage is below a predetermined threshold, and change the energy storage element to the second state when the voltage is equal to or greater than the predetermined threshold. This makes it possible to accurately control the charging and discharging of the energy storage element in the optical node while suppressing power consumption within the optical node.

[0069] Furthermore, in the optical node control device and control method according to the present disclosure, the controller may control one or more optical nodes. This allows for the collective management of one or more optical nodes. This also reduces the load when managing power supply to optical nodes. This also improves the convenience of users of the optical power supply system.

[0070] Although the contents of the present disclosure have been described above based on the embodiments, the present disclosure is not limited to these descriptions, and various modifications and improvements are possible, which will be apparent to those skilled in the art. The descriptions and drawings that form part of this disclosure should not be understood as limiting the present disclosure. Various alternative embodiments, examples, and operating techniques will be apparent to those skilled in the art from this disclosure.

[0071] Of course, the present disclosure includes various embodiments not described herein. Therefore, the technical scope of the present disclosure is defined only by the invention-specifying matters according to the scope of the claims that are appropriate from the above description.

[0072] CP Storage element CR0, CR1 Optical circulator CTL Controller DB Database DCV DC-DC converter FB Optical fiber FQ Modulator LD Laser MPU Controller N0 Control device N1, N1, N3 Optical node OSM Communication unit PD Optical receiver PVC Photoelectric conversion element SC Temperature sensor SW Switch TR Optical switch

Claims

1. A control device for an optical node, comprising a controller that controls an optical node, wherein the optical node comprises: a photoelectric conversion element that receives power supply light transmitted through an optical fiber and converts it into electric power; a storage element that stores the electric power; a temperature sensor that measures the temperature of an environment including the optical node; and a communication unit that transmits temperature information indicating the temperature, wherein the controller acquires the temperature information via the communication unit, refers to a database that records characteristic information of the storage element, acquires the characteristic information associated with the temperature, and estimates the voltage of the storage element based on an equivalent circuit model of the storage element that is determined by the characteristic information.

2. The control device for an optical node according to claim 1, wherein the optical node further comprises a switch that switches the storage element between a first state in which the power is supplied to the storage element and a second state in which the power is not supplied to the storage element, and the controller changes the storage element to the first state via the switch when the voltage is less than a predetermined threshold, and changes the storage element to the second state when the voltage is equal to or greater than the predetermined threshold.

3. The control device for an optical node according to claim 1 or 2, wherein the controller controls one or more of the optical nodes.

4. A control method for a controller that controls an optical node, wherein the optical node comprises: a photoelectric conversion element that receives power supply light transmitted through an optical fiber and converts it into electric power; a storage element that stores the electric power; a temperature sensor that measures the temperature of an environment including the optical node; and a communication unit that transmits temperature information indicating the temperature, wherein the controller acquires the temperature information via the communication unit, refers to a database that records characteristic information of the storage element, acquires the characteristic information associated with the temperature, and estimates the voltage of the storage element based on an equivalent circuit model of the storage element defined by the characteristic information.

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