Photovoltaic power generation device and optical system

Abstract

To supply required power from weak light without installing a new light source.SOLUTION: An optical power supply device according to this disclosure comprises a photoelectric conversion unit which converts input light into power, a first power storage unit which stores a part of power converted by the photoelectric conversion unit, a start unit which outputs the power stored in the first power storage unit based on voltage of the first power storage unit, a power storage control unit which outputs a remaining part the power converted in the first power storage unit based on the voltage of the first power storage unit and a second power storage unit which stores power outputted from the power storage control unit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an optical power supply device and an optical system for supplying power for driving a load device installed in an underground manhole or an overhead closure where power cannot be easily secured by optical power supply.

Background Art

[0002] As conventional optical power supply devices, for example, an optical power supply node device for a sensor network has been proposed. It is a technology in which a power supply light source for supplying power is installed, an optical signal from the power supply light source is transmitted to a plurality of node devices installed at a remote location to supply power, and a wireless sensor or a wired sensor is driven to acquire sensor information (see, for example, Non-Patent Document 1).

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In devices related to related technologies, the power required to drive a wireless sensor or a wired sensor and acquire sensor information is 510 μW and 118 μW respectively. For example, to supply power of 510 μW, when the efficiency of the photovoltaic converter is 30%, 1.7 mW of optical power supply is required. Since the optical signal intensity supplied to the existing optical access network is about 0.1 mW, there has been a problem that it is difficult to supply the power required for the wireless sensor and the wired sensor without separately installing a new light source.

[0005] In order to operate a load device such as a wireless sensor or a wired sensor, it is first necessary to operate a control device such as a microprocessor. In recent years, control devices such as microprocessors have been promoted to reduce power consumption, and after being started once, it has become possible to realize operation at an optical signal intensity of about 0.1 mW by an ultra-low power consumption operation such as a sleep mode. However, more power is required when the control device is started, and it has been difficult to start the control device with the weak optical signal supplied to the existing optical access network and operate the load device. Therefore, there has been a problem that the load device cannot be operated by a weak optical signal without installing a new light source.

[0006] In order to solve the above problems, an object of the present disclosure is to supply the necessary power from weak light without installing a new light source.

Means for Solving the Problems

[0007] To achieve the above object, the optical power supply device of the present disclosure converts light into power and stores it in two power storage units. When one power storage unit reaches the desired storage amount, the starting unit starts to supply power, and the other power storage unit starts to store power.

[0008] Specifically, the optical power supply device according to the present disclosure a photovoltaic conversion unit that converts the input light into power, A first power storage unit that stores part of the power converted by the photoelectric conversion unit; A starting unit that outputs the power stored in the first power storage unit based on the voltage of the first power storage unit; A power storage control unit that outputs the remaining part of the power converted by the photoelectric conversion unit based on the voltage of the first power storage unit; A second power storage unit that stores the power output from the power storage control unit; and is provided with.

[0009] In the optical power supply device according to the present disclosure, The power storage control unit may output the power converted by the photoelectric conversion unit after the starting unit outputs the power stored in the first power storage unit.

[0010] In the optical power supply device according to the present disclosure, The starting unit has a first threshold voltage and a second threshold voltage lower than the first threshold voltage. When the voltage of the first power storage unit becomes equal to or higher than the first threshold voltage, the starting unit starts to output the power stored in the first power storage unit. When the voltage of the first power storage unit becomes equal to or lower than the second threshold voltage, the starting unit ends the output of the power stored in the first power storage unit. The power storage control unit has a third threshold voltage higher than the first threshold voltage, and when the voltage of the first power storage unit is equal to or higher than the third threshold voltage, the power storage control unit may output the power converted by the photoelectric conversion unit.

[0011] In the optical power supply device according to the present disclosure, The power storage control unit may output the power converted by the photoelectric conversion unit in parallel with the starting unit outputting the power stored in the first power storage unit.

[0012] In the optical power supply device according to the present disclosure, The starting unit has a first threshold voltage and a second threshold voltage lower than the first threshold voltage. When the voltage of the first power storage unit becomes equal to or higher than the first threshold voltage, the starting unit starts to output the power stored in the first power storage unit. When the voltage of the first power storage unit becomes equal to or lower than the second threshold voltage, the starting unit ends the output of the power stored in the first power storage unit. The power storage control unit may have a third threshold voltage equal to the first threshold voltage, and output the power converted by the photoelectric conversion unit when the voltage of the first power storage unit is equal to or higher than the third threshold voltage.

[0013] In the optical power supply device according to the present disclosure, The starting unit A first voltage dividing resistor that divides the voltage output from the first power storage unit, When the voltage divided by the first voltage dividing resistor becomes equal to or higher than the first threshold voltage, start outputting the power stored in the first power storage unit, and when the voltage divided by the first voltage dividing resistor becomes equal to or lower than the second threshold voltage, end the output of the power stored in the first power storage unit, and a load switch, may be provided.

[0014] In the optical power supply device according to the present disclosure, The power storage control unit A second voltage dividing resistor that divides the voltage output from the first power storage unit, An N-channel FET that switches energization and interruption of a part of the power output from the photoelectric conversion unit to the power storage control unit according to the voltage divided by the second voltage dividing resistor, A P-channel FET that switches energization and interruption of the remaining part of the power output from the photoelectric conversion unit to the power storage control unit according to the switching of energization and interruption of a part of the power output from the photoelectric conversion unit to the power storage control unit in the N-channel FET, and The third threshold voltage may be determined by at least the gate threshold voltage of the N-channel FET.

[0015] Specifically, the optical system according to the present disclosure The optical power supply device, A load device that operates with the power stored in the second power storage unit, A control device that controls the operation of the load device based on the voltage output by the photoelectric conversion unit, the voltage of the first power storage unit, and the voltage of the second power storage unit, is provided.

[0016] Incidentally, the above inventions can be combined as much as possible.

Advantages of the Invention

[0017] According to the present disclosure, it is possible to supply necessary power from a weak optical signal without installing a new light source.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below. These examples are merely illustrative, and the present disclosure can be implemented in various modified forms based on the knowledge of those skilled in the art. In the present specification and drawings, components having the same reference numerals indicate the same components.

[0020] (Embodiment 1) An example of the schematic configuration of the optical system according to the present embodiment is shown in FIG. 1. The optical system 10 includes an optical power supply device 11, a control device 7, and a load device 8.

[0021] The optical power supply device 11 includes a photoelectric conversion unit 1 that converts the input light into electric power, a starting power storage unit 3 that functions as a first power storage unit for storing a part of the electric power converted by the photoelectric conversion unit 1, a starting unit 6 that outputs the electric power stored in the starting power storage unit 3 based on the voltage of the starting power storage unit 3, a power storage control unit 4 that outputs the remaining part of the electric power converted by the photoelectric conversion unit 1 based on the voltage of the starting power storage unit 3, and an operating power storage unit 5 that functions as a second power storage unit for storing the electric power output from the power storage control unit.

[0022] The photoelectric conversion unit 1 is connected to the optical fiber 9. The photoelectric conversion unit 1 converts the light input from the optical fiber 9 into electric power, outputs a part of the converted electric power to the startup power storage unit 3, and outputs the remaining part of the converted electric power to the power storage control unit 4.

[0023] The optical power supply device 11 may be provided with reverse current prevention units 2-1 and 2-2 between the photoelectric conversion unit 1 and the startup power storage unit 3, and between the photoelectric conversion unit 1 and the power storage control unit 4, respectively, to prevent reverse current of electric power. For example, the reverse current prevention units 2-1 and 2-2 may be Schottky barrier diodes.

[0024] A part of the electric power converted by the photoelectric conversion unit 1 is input to the startup power storage unit 3. The startup power storage unit 3 stores the electric power from the photoelectric conversion unit 1. Hereinafter, the voltage of the startup power storage unit 3 is denoted as Vsupply.

[0025] The startup unit 6 outputs the electric power stored in the startup power storage unit 3 based on the voltage Vsupply of the startup power storage unit 3. For example, when the startup unit 6 is connected to the control device 7 as shown in FIG. 1, the control device 7 may be started by the startup unit 6 outputting the electric power stored in the startup power storage unit 3 to the control device 7. An example of the configuration of the startup unit 6 will be described later.

[0026] The remaining part of the electric power converted by the photoelectric conversion unit 1 is input to the power storage control unit 4. The power storage control unit 4 outputs the electric power from the photoelectric conversion unit 1 based on the voltage Vsupply of the startup power storage unit 3. For example, the power storage control unit 4 may control the output of the electric power from the photoelectric conversion unit 1 so that the operating power storage unit 5 starts storing power when the voltage Vsupply of the startup power storage unit 3 reaches the voltage required to operate the control device 7.

[0027] The operating power storage unit 5 stores the electric power from the power storage control unit 4.

[0028] The control device 7 monitors the voltage output by the photoelectric conversion unit 1, the voltage of the startup power storage unit 3, and the voltage of the operation power storage unit 5, and controls the operation of the load device 8 based on these. For example, if the light supplied by the optical fiber 9 is an optical signal, an operation instruction signal can be superimposed on the output voltage of the photoelectric conversion unit 1 by modulating the optical signal. When there is an instruction to operate the load device 8 by the operation instruction signal, the control device 7 checks the voltage of the operation power storage unit 5, and after confirming that the power necessary to operate the load device 8 is stored, it may give an operation instruction to the load device 8. Note that the control device 7 according to the present embodiment can also be realized by a computer and a program, and it is also possible to record the program on a recording medium or provide it through a network.

[0029] The load device 8 operates according to the operation instruction of the control device 7 using the power stored in the operation power storage unit 5. As the load device 8 according to the present embodiment, general various devices such as an N×M optical switch, an inclination sensor, a water level sensor, a wireless transmission device, and an optical transmission device may be used.

[0030] An example of the configuration of the startup unit 6 is shown in FIG. 2. The startup unit 6 includes a startup voltage dividing resistor 601 and a load switch 602. Further, the load switch 602 includes an input terminal 603, an output terminal 604, and an output control terminal 605.

[0031] The startup voltage dividing resistor 601 divides the voltage Vsupply of the startup power storage unit 3 and inputs the divided voltage to the output control terminal 605 of the load switch 602.

[0032] The load switch 602 has the power Vsupply stored in the startup power storage unit 3 input to the input terminal 603. The load switch 602 outputs the power Vsupply input to the input terminal 603 from the output control terminal 605 based on the voltage input to the output control terminal 605.

[0033] Specifically, the load switch 602 is a semiconductor element that can conduct or cut off power from the input terminal 603 to the output terminal 604 according to the magnitude relationship between the voltage input to the output control terminal 605 and the threshold voltage of the load switch 602. A commercially available product may be used for the load switch 602. As an example of the load switch 602, Non-Patent Document 2 can be cited.

[0034] Here, assuming that the threshold voltage of the output control terminal 605 is Vthreshold, the voltage-side resistance value of the startup voltage-dividing resistor 601 is R1, and the ground-side resistance value is R2, the relationship of Equation (1) is obtained using the voltage Vsupply of the startup power storage unit 3. (Equation 1) Vthreshold = Vsupply × R2 / (R1 + R2) (1) The right side of Equation (1) is the voltage input to the output control terminal 605. That is, when the voltage Vsupply of the startup power storage unit 3 satisfies Equation (1), the conduction of power from the input terminal 603 to the output terminal 604 is started, and power is output to the control device 7.

[0035] Therefore, in the startup unit 6, it is possible to start the control device 7 at an arbitrary voltage by adjusting the resistance value of the startup voltage-dividing resistor 601. For example, assume that the threshold voltage Vthreshold of the output control terminal 605 of the load switch 602 is 1V. In this case, in order to start the control device 7 when the voltage Vsupply of the startup power storage unit 3 is 2V, it is necessary to set R1 = R2. As a result, when the voltage Vsupply of the startup power storage unit 3 is 2V, a voltage of 1V is input to the output control terminal 605 by the startup voltage-dividing resistor 601. At this time, since the voltage of the output control terminal 605 is equal to or higher than the threshold voltage Vthreshold (= 1V), the load switch 602 energizes the power from the startup power storage unit 3 from the input terminal 603 to the output terminal 604. As a result, when the voltage Vsupply of the startup power storage unit 3 becomes 2V, the load switch 602 starts to output the power from the startup power storage unit 3 from the output terminal 604 to the control device 7, and it becomes possible to start the control device 7.

[0036] In a general load switch 602, since the voltage input to the output control terminal 605 is digitally operated, the output control terminal 605 is provided with a hysteresis characteristic. Specifically, the load switch 602 has two threshold voltages, and the second threshold voltage for turning off the output from the output terminal 604 is set lower than the first threshold voltage for turning on the output from the output terminal 604.

[0037] Therefore, when the voltage input to the output control terminal 605 of the load switch 602 becomes equal to or higher than the first threshold voltage, the load switch 602 starts outputting power from the output terminal 604. After starting to output power from the output terminal 604, the load switch 602 ends the power output from the output terminal 604 when the voltage input to the output control terminal 605 becomes equal to or lower than the second threshold voltage.

[0038] By using the load switch 602, the starting unit 6 can electrically disconnect the starting power storage unit 3 and the control device 7 until the power required for starting the control device 7 is stored in the starting power storage unit 3. When the power required for the starting power storage unit 3 is stored, the starting unit 6 sets the resistance value of the voltage dividing resistor 403 for charge control so that the voltage of the output control terminal 605 becomes equal to or higher than the first threshold voltage. Thereby, the starting unit 6 can supply the power required for starting the control device 7. That is, since the starting unit 6 can supply a larger power to the control device 7 than the power constantly output from the photoelectric conversion unit 1, the control device 7 can be started.

[0039] An example of the configuration of the charge control unit 4 is shown in FIG. 3. The charge control unit 4 may be composed of an N-channel FET 401, a P-channel FET 402, a voltage dividing resistor 403 for charge control, and a pull-up resistor 404. Also, a part of the power output from the photoelectric conversion unit 1 to the charge control unit 4 is input to the pull-up resistor 404, and the remainder is input to the source terminal of the P-channel FET 402.

[0040] The voltage dividing resistor 403 for charge control divides the voltage Vsupply of the starting power storage unit 3 and inputs the divided voltage to the gate terminal of the N-channel FET 401.

[0041] As described above, for the N-channel FET 401, the voltage divided by the voltage dividing resistor 403 for power storage control is input to the gate terminal. For the N-channel FET 401, a part of the power output from the photoelectric conversion unit 1 to the power storage control unit 4 is input to the drain terminal via the pull-up resistor 404. For the N-channel FET 401, the source terminal is connected to the ground. When the voltage input to the gate terminal of the N-channel FET 401 is equal to or higher than the gate threshold voltage, the N-channel FET 401 conducts between the drain terminal and the source terminal, and outputs the power input to the drain terminal from the source terminal.

[0042] For the P-channel FET 402, the voltage of the drain terminal of the N-channel FET 401 is input to the gate terminal. For the P-channel FET 402, as described above, the remainder of the power output from the photoelectric conversion unit 1 to the power storage control unit 4 is input to the source terminal. For the P-channel FET 402, the drain terminal is connected to the operating power storage unit 5.

[0043] Here, in the N-channel FET 401, when the N-channel FET 401 conducts between the drain terminal and the source terminal, the voltage of the drain terminal of the N-channel FET 401 decreases to near 0V. Along with this, the voltage of the gate terminal of the P-channel FET 402 also decreases to near 0V. At this time, the P-channel FET 402 conducts between the source terminal and the drain terminal, and outputs the power input to the source terminal from the drain terminal to the operating power storage unit 5. Thereby, the operating power storage unit 5 starts charging.

[0044] That is, when the N-channel FET 401 conducts or cuts off the power between the drain terminal and the source terminal, accordingly, the P-channel FET 402 also conducts or cuts off the power between the source terminal and the drain terminal. Therefore, whether the power storage control unit 4 outputs power to the operating power storage unit 5 is determined by the magnitude relationship between the voltage Vsupply of the starting power storage unit 3 and the gate threshold voltage of the N-channel FET 401.

[0045] Assuming that the gate threshold voltage of the N-channel FET 401 is Vg_threshold, the voltage-side resistance value of the voltage-dividing resistor 403 for power storage control is R3, and the ground-side resistance value is R4, the relationship of Equation (2) is obtained using the voltage Vsupply of the startup power storage unit 3. (Equation 2) Vg_threshold = Vsupply × R4 / (R3 + R4) (2) The right side of Equation (2) is the voltage input to the gate terminal of the N-channel FET 401. That is, when the voltage Vsupply of the startup power storage unit 3 satisfies Equation (2), as described above, the N-channel FET 401 conducts the power between the drain terminal and the source terminal, and the P-channel FET 402 conducts the power between the source terminal and the drain terminal, and power is output to the operating power storage unit 5.

[0046] Therefore, in the power storage control unit 4, by adjusting the resistance value of the voltage-dividing resistor 403 for power storage control, it becomes possible to start storing power in the operating power storage unit 5 at an arbitrary voltage. For example, assume that the gate threshold voltage Vg_threshold of the N-channel FET 401 is 1V. In this case, in order to start storing power in the operating power storage unit 5 when the voltage Vsupply of the startup power storage unit 3 is 2V, it is necessary to set R3 = R4. As a result, when the voltage Vsupply of the startup power storage unit 3 is 2V, a voltage of 1V is input to the gate terminal of the N-channel FET 401 by the voltage-dividing resistor 403 for power storage control. At this time, since the voltage of the gate terminal of the N-channel FET 401 becomes equal to or higher than the gate threshold voltage Vg_threshold (= 1V), the N-channel FET 401 conducts the power between the drain terminal and the source terminal. Along with this, the P-channel FET 402 conducts the power between the source terminal and the drain terminal. As a result, when the voltage Vsupply of the startup power storage unit 3 becomes 2V, the P-channel FET 402 starts to output the remainder of the power input from the photoelectric conversion unit 1 to the power storage control unit 4 from the drain terminal to the operating power storage unit 5, and it becomes possible to start storing power in the operating power storage unit 5.

[0047] Note that the operation of the power storage control unit 4 is similar to that of the starting unit 6 in that the output from the drain terminal of the P-channel FET 402 becomes ON when the voltage at the gate terminal of the N-channel FET 401 becomes equal to or higher than the gate threshold voltage. However, there is no hysteresis characteristic at the gate terminal of the N-channel FET 401, and it is different in that the gate threshold voltage of the N-channel FET 401 at which the output from the drain terminal of the P-channel FET 402 becomes OFF is equal to the gate threshold voltage of the N-channel FET 401 at which the output from the drain terminal of the P-channel FET 402 becomes ON.

[0048] Therefore, when the voltage Vsupply of the starting power storage unit 3 becomes less than 2V, the voltage input to the gate terminal of the N-channel FET 401 becomes less than 1V. As a result, since the voltage at the gate terminal of the N-channel FET 401 becomes less than the gate threshold voltage (=1V), the power storage from the drain terminal of the P-channel FET 402 to the operating power storage unit 5 stops. In the power storage control unit 4, by adjusting the resistance value of the power storage control voltage dividing resistor 403, the power storage of the operating power storage unit 5 can be started at an arbitrary voltage Vsupply of the starting power storage unit 3.

[0049] In the optical power supply device 11 according to the present embodiment, after the starting unit 6 outputs the power stored in the starting power storage unit 3, the power storage control unit 4 may output the power converted by the photoelectric conversion unit 1. This can be realized, for example, when the power storage control voltage dividing resistor 403 and the starting voltage dividing resistor 601 have the same configuration, by making the gate threshold voltage of the N-channel FET 401 larger than the first threshold voltage of the starting unit 6.

[0050] In the optical power supply device 11 according to the present embodiment, in parallel with the starting unit 6 outputting the power stored in the starting power storage unit 3, the power storage control unit 4 may output the power converted by the photoelectric conversion unit 1. This can be realized, for example, when the power storage control voltage dividing resistor 403 and the starting voltage dividing resistor 601 have the same configuration, by making the gate threshold voltage of the N-channel FET 401 equal to the first threshold voltage of the starting unit 6.

[0051] As described above, according to the present disclosure, it is possible to supply the necessary power from a weak optical signal without installing a new light source.

Industrial Applicability

[0052] The optical power supply device and the optical system according to the present disclosure can be applied to the information and communication industry.

Explanation of Signs

[0053] 1: Photoelectric conversion unit 2-1, 2-2: Backflow prevention unit 3: Starting storage unit 4: Storage control unit 5: Operating storage unit 6: Starting unit 7: Control device 8: Load device 9: Optical fiber 10: Optical system 11: Optical power supply device 401: N-channel FET 402: P-channel FET 403: Voltage dividing resistor for storage control 404: Pull-up resistor 601: Starting voltage dividing resistor 602: Load switch 603: Input terminal 604: Output terminal 605: Output control terminal

Claims

1. A photoelectric conversion unit that converts the input light into electric power, a first power storage unit that stores a part of the electric power converted by the photoelectric conversion unit, a starting unit that outputs the electric power stored in the first power storage unit to a control device that controls the operation of a load device based on the voltage of the first power storage unit, a power storage control unit that outputs the remaining part of the electric power converted by the photoelectric conversion unit based on the voltage of the first power storage unit, a second power storage unit that stores the electric power output from the power storage control unit and outputs the stored electric power to the load device, comprising: when the voltage of the first power storage unit becomes equal to or higher than a first threshold voltage which is the voltage when the electric power necessary for starting the control device is stored in the first power storage unit, the starting unit starts outputting the electric power stored in the first power storage unit to start the control device, when the voltage of the first power storage unit is equal to or higher than a third threshold voltage which is equal to or higher than the first threshold voltage, the power storage control unit outputs the electric power converted by the photoelectric conversion unit A photovoltaic power supply device.

2. The third threshold voltage is higher than the first threshold voltage, after the starting unit outputs the electric power stored in the first power storage unit, the power storage control unit outputs the electric power converted by the photoelectric conversion unit The photovoltaic power supply device according to claim 1, characterized in that.

3. The third threshold voltage is equal to the first threshold voltage, in parallel with the starting unit outputting the electric power stored in the first power storage unit, the power storage control unit outputs the electric power converted by the photoelectric conversion unit The photovoltaic power supply device according to claim 1, characterized in that.

4. when the voltage of the first power storage unit becomes equal to or lower than a second threshold voltage which is lower than the first threshold voltage, the starting unit also ends the output of the electric power stored in the first power storage unit The photovoltaic power supply device according to any one of claims 1 to 3, characterized in that.

5. The power storage control unit a voltage dividing resistor that divides the voltage output from the first power storage unit, an N-channel FET that switches the energization and interruption of a part of the electric power output from the photoelectric conversion unit to the power storage control unit according to the voltage divided by the voltage dividing resistor, a P-channel FET that switches the energization and interruption of the remaining part of the electric power output from the photoelectric conversion unit to the power storage control unit according to the switching of the energization and interruption of a part of the electric power output from the photoelectric conversion unit to the power storage control unit in the N-channel FET, and is provided with: The third threshold voltage is determined by at least the gate threshold voltage of the N-channel FET The photovoltaic power supply device according to any one of claims 1 to 4, characterized in that

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