JP2000350387A - Optical power-feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the decrease in a photoelectric conversion efficiency based on the temperature increase of a photoelectric conversion element by converting each of light beam that is branched into a plurality of parts to power by the photoelectric conversion element individually. SOLUTION: An optical power is generated by a laser 120 that is an emission means using power that is supplied from a power supply 110 of a main circuit 100 and is carried to a sub circuit 300 by an optical fiber 200. Then, the optical power is branched into two directions by a branching filter 330. Then, each optical power is converted to power by a photoelectric conversion means 310 individually and is supplied to a load device 320. In this case, the photoelectric conversion means 310 is subjected to stable voltage operation by an output voltage stabilization means 340 that is connected in parallel with the photoelectric conversion means 310. Also, a diode (reverse flow prevention means) 350 is provided between the output stabilization means 340 and the photoelectric conversion means 310, thus preventing the breakdown of the photoelectric conversion element due to inverse flow. By stabilizing an output voltage so that the maximum photoconductive conversion efficiency of the photoelectric conversion means 310 can be realized, power can be supplied to the load device 320 with high conductivity conversion efficiency and stable voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical power feeding device for generating optical power, converting the power after transporting the power, and supplying the power to a load device.

[0002]

2. Description of the Related Art FIG.
Shown in This device comprises a main circuit for generating optical power, an optical transmission line for transmitting the optical power, and a sub-circuit for receiving the optical power and converting it to electric power.

In FIG. 12, 100 is a main circuit for generating optical power, 200 is an optical fiber which is an optical transmission line for transmitting the optical power, 300 is a sub-circuit for receiving the optical power and converting it to electric power, and 110 is a power circuit. Power supply,
Reference numeral 120 denotes a laser as light emitting means for converting electric power to optical power; 310, a plurality of photoelectric conversion elements; and photoelectric conversion means for converting optical power to electric power.
The load device is a device to which the power generated by the power supply 10 is supplied.

[0004] A conventional optical power feeding device is composed of a main circuit 100.
To generate optical power, and the sub-circuit 30
The optical power is conveyed to 0, the optical power is converted into electric power by the sub-circuit 300, and power is supplied to the device.

[0005]

Problems to be solved by the present invention will be described below.

In a conventional optical power feeding device, optical power is continuously or periodically generated on the main circuit side, conveyed by an optical transmission line, and radiated to a photoelectric conversion element in a sub-circuit to be converted into electric power. Was.

At this time, when the device is continuously operated under the condition that the light power applied to the photoelectric conversion element is large, the temperature of the photoelectric conversion element rises due to the heat generated by the photoelectric conversion loss, thereby increasing the photoelectric conversion efficiency. However, there was a problem that it decreased. There is also a problem that the life of the element is shortened due to an increase in the element temperature. Solving these problems is one of the problems to be solved by the present invention.

Next, problems that occur when power is supplied to the equipment will be described.

In the conventional optical power supply apparatus shown in FIG. 12, a single GaAs photoelectric conversion element is used in series as the photoelectric conversion means 310, and a constant optical power is applied to this photoelectric conversion element. FIG. 13 shows the relationship between the output current and the output voltage.

The photoelectric conversion element is denoted by B (output voltage 9) in FIG.
(00 mV), the photoelectric conversion efficiency is maximized.
However, when the impedance of the device that receives power is small, the operating point of the photoelectric conversion element is, for example, A A in FIG.
When this impedance is large, the operating point of the photoelectric conversion element is, for example, C in FIG. As described above, when a device to which power is supplied does not operate at a constant impedance, the operating point of the photoelectric conversion element changes due to the change in the impedance, so that power cannot be supplied to the device at a constant voltage and maximum photoelectric conversion cannot be performed. Since the photoelectric conversion element does not operate at the point where the efficiency can be obtained, the photoelectric conversion efficiency also decreases. Solving this problem is another one of the problems to be solved by the present invention.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, suppress a decrease in photoelectric conversion efficiency due to a rise in temperature of a photoelectric conversion element during continuous operation, and provide a highly efficient and stable voltage output with high reliability. An optical power supply device is provided.

[0012]

In order to solve the above-mentioned problems, in an optical power feeding apparatus according to the present invention, a main circuit for generating optical power, and an optical transmission for conveying the optical power generated in the main circuit are provided. Optical power transmitted through the optical transmission line into a plurality of sub-circuits of a conventional optical power transmission device, which includes a sub-circuit and a sub-circuit that receives the optical power carried by the optical transmission line and converts the received optical power into electric power. Demultiplexing means, photoelectric conversion means for individually converting each of a plurality of demultiplexed lights into electric power by a photoelectric conversion element, and output voltage stabilizing means for operating the photoelectric conversion element at a stable output voltage. If necessary, a backflow preventing means for preventing a current from flowing backward from the output voltage stabilizing means to the photoelectric conversion element is added.

In the present invention, as described above, each of a plurality of split lights is individually converted into a photoelectric conversion element (of course,
This is a plurality of elements), and the temperature rise of the element due to light irradiation is reduced as compared with the case where one element is used as in the related art. As a result, the temperature rise of the element is reduced. Also, the decrease in the photoelectric conversion efficiency based on the conventional technology is suppressed as compared with the related art. Note that a beam splitter such as a half mirror can be used as the demultiplexing unit.

Further, as described above, the optical power feeding device of the present invention is provided with output voltage stabilizing means for operating the photoelectric conversion element at a stable output voltage. The output voltage stabilizing means reduces output voltage fluctuation of the photoelectric conversion element based on impedance fluctuation of a device to which power is supplied,
It plays a role in maintaining the output power or the photoelectric conversion efficiency at or near a maximum value. Specifically, as described later, a secondary battery and a voltage control diode (for example, a Zener diode) are effectively used as the output voltage stabilizing means.

Further, as described above, the optical power feeding device of the present invention is provided with backflow prevention means for preventing current from flowing back from the output voltage stabilizing means to the photoelectric conversion element, if necessary. This is from the output voltage stabilization means to the photoelectric conversion element,
This is for preventing a current from flowing in a direction opposite to the output current of the photoelectric conversion element, thereby preventing the photoelectric conversion element from being destroyed by the current. A diode is effectively used as the backflow preventing means.

As described above, the optical power feeding device having the above-described configuration suppresses a decrease in photoelectric conversion efficiency due to a rise in temperature when the device is continuously operated, and furthermore, controls the photoelectric conversion element with respect to the light irradiation power. High reliability, which can maintain stable continuous operation of the equipment because it can be operated stably at the voltage value at which the maximum power can be obtained and the power can be supplied to the equipment at the stabilized voltage. Become a device.

Further, since the temperature rise of the photoelectric conversion element due to light irradiation is reduced as compared with the prior art, the life of the element is prolonged and the reliability of the device is further improved.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to Examples, but the present invention is not limited thereto.

(Embodiment 1) FIG. 1A is a view schematically showing an optical power feeding device according to a first embodiment. In the drawing, parts in the conventional optical power feeding device shown in FIG. The same numbers are used for the same parts.

In the optical power feeding device shown in FIG. 1A, 100 is a main circuit for generating optical power, 200 is an optical fiber which is an optical transmission line for transmitting optical power, and 300 is optical power which receives optical power and converts it into electric power. Sub-circuit, and 110
Reference numeral 120 denotes a power supply as a power supply unit; 120, a laser as a light emitting unit that converts electric power into optical power; 310, a photoelectric conversion unit including a photoelectric conversion element that converts optical power into electric power;
0 is a load device that is a device to which the power generated by the photoelectric conversion unit 310 is supplied, 330 is a duplexer that is a unit that splits the optical power emitted from the optical fiber 200, 340
Is an output voltage stabilizing means for causing the photoelectric conversion means 310 to perform a stable voltage operation, and 350 is a means for preventing a current from flowing backward from the output voltage stabilizing means 340 to the photoelectric conversion means 310 (in a direction opposite to the output current). There is a certain backflow prevention means.

Next, the operation of the optical power feeding device of the present invention will be described with reference to the present embodiment.

The power supplied from the power supply 110 serving as the power supply means in the main circuit 100 is used to generate optical power in the laser 120 serving as the light emitting means, and the optical power is generated by the optical fiber 200 serving as the optical transmission line. Transport to
The conveyed optical power is demultiplexed in two directions by a demultiplexer 330 which is a demultiplexing means in the sub-circuit 300. Then, each optical power is individually converted into electric power by the photoelectric conversion means 310 (photoelectric conversion element) and supplied to the load device 320. At this time, the output voltage stabilizing means 340 connected in parallel with the photoelectric conversion means 310 causes the photoelectric conversion means 310 to perform a stable voltage operation. Thereby, the output voltage of the photoelectric conversion element is kept stable. By stabilizing this output voltage so that the highest photoelectric conversion efficiency of the photoelectric conversion unit 310 is realized, power can be supplied to the load device 320 with high photoelectric conversion efficiency and a stable voltage. Further, by splitting the optical power and irradiating the photoelectric conversion unit 310 with the optimal optical power, the element can be operated with the maximum photoelectric conversion efficiency. Also, means 350 for preventing backflow of current from output voltage stabilizing means 340 to the photoelectric conversion element.
By disposing a diode between the output voltage stabilizing unit 340 and the photoelectric conversion unit 310, it is possible to prevent the photoelectric conversion element from being destroyed by a current flowing from the output voltage stabilizing unit 340 to the photoelectric conversion unit 310.

FIG. 2 shows an example of the operating time dependency of the output voltage of the photoelectric conversion element when the optical power feeding device of this embodiment and the conventional optical power feeding device are operated. The experimental conditions here are as follows.

The optical fiber 200 is a quartz fiber having a core diameter of 200 μm and a cladding diameter of 250 μm, and is of a step index type. The optical power emitted from the optical fiber 200 is 860 mW, the optical power split by the splitter 330 and applied to the photoelectric conversion means 310 is 4
30 mW. Each photoelectric conversion means 310 has one p
In this example, two GaAs devices having an n-junction are connected in series. Therefore, in the sub-circuit 300, four GaAs
The elements are connected in series. As shown in FIG. 1B, as the output voltage stabilizing means 340,
A battery in which three NiCd secondary batteries with an output voltage of 1.2 V are connected in series and a Zener diode are connected in parallel are used, and these are connected in parallel with the above-mentioned four GaAs devices connected in series. , And connect them according to the output voltage. As the load device 320, an MD player is used.

In FIG. 2, the solid line indicates the operating time dependency of the photoelectric conversion element output voltage in the optical power feeding device of the present invention, and the dotted line indicates the operating time dependency of the photoelectric conversion element output voltage in the conventional optical power feeding device. Is shown. As is apparent from FIG. 2, in the conventional optical power feeding apparatus, the output voltage of the photoelectric conversion element fluctuates with the fluctuation of the impedance of the load device 320 (MD player). In the device, the output voltage of the photoelectric conversion element is constant without depending on the operation time of the device. As described above, the optical power feeding device of the present invention can operate the photoelectric conversion element with a stable output voltage as compared with the conventional one, and supplies power to the load device with a constant voltage or a stable voltage. be able to.

The reason why the output voltage of the photoelectric conversion element in the optical power feeding device of the present invention is kept constant or almost constant even if the impedance of the load device fluctuates is as follows. That is, when the impedance of the load device decreases and the load current increases and exceeds the output current of the photoelectric conversion element, the excess is supplied from the NiCd secondary battery (output voltage stabilizing means) to the load device. When the impedance of the load device increases and the load current decreases, and the output current of the photoelectric conversion element exceeds the load current, the excess is N
It flows to the iCd secondary battery and is useful for charging the battery. As a result, the output voltage of the photoelectric conversion element is kept within a narrow range between the charging voltage and the discharging voltage of the NiCd secondary battery. Further, in this embodiment, a Zener diode is also used. Therefore, when the charging voltage of the NiCd secondary battery becomes higher than the Zener voltage value of the Zener diode, a current flows through the Zener diode, and the charging voltage value becomes the Zener voltage value. The output voltage is kept within a narrower range than in the case where the Zener diode is not used.

The above is the reason why the output voltage of the photoelectric conversion element is kept constant or almost constant even if the impedance of the load device fluctuates in the embodiment of the present invention.

FIG. 3 shows the photoelectric conversion means 3 used in this embodiment.
An example of the relationship between the electrical output and the output voltage when irradiating the optical power of 10 (one in which four GaAs elements are connected in series) is shown. From FIG. 3, it can be seen that the photoelectric conversion element has an electrical output value dependence on the output voltage, and that the photoelectric conversion element used in this embodiment can obtain the maximum power when the photoelectric conversion element output voltage is about 3.6 V. Understand.

From this, it was found that the voltage of the photoelectric conversion element was about 3.6 V
Output voltage stabilizing means operating at a stable voltage of (in the present embodiment, three NiCd secondary batteries with an output voltage of 1.2 V are connected in series to triple the output voltage, and a Zener diode is connected in parallel. Connected), the output voltage of the photoelectric conversion element is constant without depending on the impedance fluctuation during the operation of the load device, and the maximum output power can be obtained. Here, the same effect can be obtained for an element which can obtain the maximum output power at an output voltage different from about 3.6 V by using an output voltage stabilizing means for stabilizing the output voltage to that voltage.

FIG. 4 shows the photoelectric conversion means 3 used in this embodiment.
10 shows an example of the relationship between the photoelectric conversion efficiency and the output voltage of 10 (three GaAs elements connected in series). FIG. 4 shows that the photoelectric conversion efficiency has an output voltage dependency, and that the photoelectric conversion element used in this embodiment has the maximum efficiency when the output voltage of the photoelectric conversion element is about 3.6 V.
From this, by providing the output voltage stabilizing means for operating the photoelectric conversion element at a stable voltage of about 3.6 V, the photoelectric conversion efficiency of the photoelectric conversion element is constant without depending on the operation time of the device, and the maximum efficiency is increased. Will be obtained. Here, the same effect can be obtained for an element which can obtain the maximum output power at an output voltage different from about 3.6 V by using an output voltage stabilizing means for stabilizing the output voltage to that voltage.

FIG. 5 shows a NiCd secondary battery having an output voltage of 1.2 V as an output voltage stabilizing means as described above.
An example of the operating time dependence of the electrical output of the photoelectric conversion means 310 when a serially connected one having an output voltage of 3.6 V and a Zener diode connected in parallel is shown in FIG. This is shown in comparison with the case of the power supply device. The solid line is the value in the case of the optical power feeding device of the present invention, and the dotted line is the value in the case of the conventional optical power feeding device. In FIG. 5, in the conventional optical power feeding device, the power of the photoelectric conversion element fluctuates along with the impedance fluctuation of the load device (MD player). However, in the optical power feeding device of the present invention, the output of the photoelectric conversion element is changed. It can be seen that the voltage is constant irrespective of the impedance fluctuation, and that the maximum power is supplied to the load device. Thus, the photoelectric conversion means 31
As output voltage stabilizing means 340 connected in parallel to 0,
By selecting a secondary battery having an output voltage equal to the operating voltage at which the maximum power of the photoelectric conversion element is obtained, it is possible to continuously supply the maximum power that can be supplied by the photoelectric conversion unit 310 to the load device. . The output voltage here is 3.6V
However, when the type and the number of photoelectric conversion elements are changed, it is possible to continuously supply the maximum power at the optimum output voltage corresponding thereto.

FIG. 6 shows a NiCd secondary battery having an output voltage of 1.2 V as an output voltage stabilizing means as described above.
An example of the dependence of the photoelectric conversion efficiency of the photoelectric conversion means 310 on the operation time of the device of the present invention when a serially connected one (output voltage: 3.6 V) and a Zener diode connected in parallel is used. The solid line is the value of the optical power supply device of the present invention, and the dotted line is the value of the conventional optical power supply device.
In FIG. 6, in the conventional optical power feeding device, the photoelectric conversion efficiency of the photoelectric conversion element fluctuates along with the impedance fluctuation of the load device (MD player). It can be seen that the photoelectric conversion efficiency is constant without depending on the impedance fluctuation and is kept at its maximum value. Thus, the output voltage stabilizing means 340 connected in parallel to the photoelectric conversion means 310
By selecting a secondary battery having an output voltage equal to the operating voltage when the photoelectric conversion efficiency is maximized, the photoelectric conversion unit 310 can always be operated in the state where the photoelectric conversion efficiency is maximized.

FIG. 7 shows an example of the light irradiation time dependency of the temperature of the photoelectric conversion element when the photoelectric conversion means 310 is irradiated with light power. The solid line is the value of the optical power feeding device of the present invention, and the dotted line is the value of the conventional optical power feeding device.
FIG. 7 shows that the temperature rise of the photoelectric conversion element in the optical power feeding apparatus of the present invention is significantly smaller than the temperature rise of the photoelectric conversion element in the conventional optical power feeding apparatus. As described above, the optical power emitted from the optical fiber is demultiplexed and received by the plurality of photoelectric conversion elements, so that the photoelectric conversion efficiency caused by the increase in the light irradiation time to the photoelectric conversion unit 310 causes the photoelectric conversion efficiency loss. It is possible to suppress the temperature rise of the conversion element.

FIG. 8 shows the photoelectric conversion efficiency (value standardized by the initial value) when the photoelectric conversion means 310 is irradiated with light power.
1 shows an example of the light irradiation time dependency. The solid line is a value in the optical power feeding device of the present invention, and the dotted line is a value in the conventional optical power feeding device. FIG. 8 shows that the decrease in photoelectric conversion efficiency due to the temperature rise of the photoelectric conversion element due to light irradiation in the optical power supply device of the present invention is significantly smaller than the decrease in photoelectric conversion efficiency in the conventional optical power supply device. As described above, the optical power emitted from the optical fiber is demultiplexed and received by the plurality of photoelectric conversion elements, so that the photoelectric conversion efficiency caused by the increase in the light irradiation time to the photoelectric conversion unit 310 causes the photoelectric conversion efficiency loss. A rise in the temperature of the conversion element can be suppressed, and the decrease in photoelectric conversion efficiency can be significantly reduced as compared with the conventional optical power feeding device.

(Embodiment 2) Next, a case where the configuration of the demultiplexing means is changed will be described.

FIG. 9 is a schematic diagram showing a second embodiment, that is, an optical power feeder having means for splitting light emitted from an optical fiber by three beam splitters.

In FIG. 9, reference numeral 310 denotes a photoelectric conversion element which is a photoelectric conversion means for converting optical power into electric power; 320, a load device which is a device to which the power generated by the photoelectric conversion element is supplied; A beam splitter (half mirror) 331 which is a means for splitting the obtained optical power with a one-to-one optical power, a beam splitter 331 which is a means for splitting the optical power emitted from the optical fiber with a one-to-two optical power, Reference numeral 332 denotes a beam splitter, which is a unit that splits the optical power emitted from the optical fiber with 1: 3 optical power, and 340, a secondary battery that is a unit that operates the photoelectric conversion element at a constant voltage.

The optical power emitted from the optical fiber, which is an optical transmission line, is converted into a one-to-three optical power by a beam splitter 332, which is a demultiplexing means in a sub-circuit, respectively.
The light is split into two directions of 0 and the beam splitter 331. The light power transmitted through the beam splitter 331 is 1
The light is split into two directions of the photoelectric conversion means 310 and the beam splitter 330 with the power of the pair. Then, the optical power transmitted through the beam splitter 330 is split into two directions by a one-to-one optical power, and is radiated to the photoelectric conversion means 310 respectively. In this way, the four photoelectric conversion elements are irradiated with light power of uniform intensity.

In the photoelectric conversion means 310, all of the photoelectric conversion elements are connected in series, and in parallel with the photoelectric conversion elements, a secondary battery and a Zener diode are used as output voltage stabilization means 340 for stabilizing the output voltage of the photoelectric conversion means. And are connected in parallel. The optical power applied to the photoelectric conversion unit 310 is converted into electric power, and is output at a voltage stabilized by the output voltage stabilization unit 340 (secondary battery and zener diode) connected in parallel with the photoelectric conversion unit 310. . When the impedance of the load device 320 is high and the load current is small, and the output current from the photoelectric conversion means 310 exceeds the load current, the excess becomes the charging current of the secondary battery 340, and the impedance of the load device 320 is low and the load When the current is large and exceeds the output current from the photoelectric conversion means 310, the excess is due to the rechargeable battery 34
Supplied from 0. Also, the charging voltage of the secondary battery 340 does not exceed the Zener voltage of the Zener diode.

In this embodiment, the optical fiber 200 is a silica fiber having a core diameter of 200 μm and a cladding diameter of 250 μm, and is of a step index type. Optical fiber 2
00 is 860 mW, and the light power applied to the photoelectric conversion unit 310 is 215 mW.
Each photoelectric conversion means 310 (photoelectric conversion element) is a GaAs element having one pn junction. As the output voltage stabilization means 340, three NiCd secondary batteries are connected in series to achieve an output voltage of 3.6V. And a Zener diode connected in parallel was used.

FIG. 10 shows an example of the dependence of photoelectric conversion efficiency on light irradiation power to the photoelectric conversion element when one photoelectric conversion means 310 (photoelectric conversion element) is irradiated with light. FIG. 10 shows that the photoelectric conversion efficiency decreases as the light irradiation power to the photoelectric conversion element increases. In the present embodiment, the optical power emitted from the optical fiber is split into four using the splitter and the photoelectric conversion is performed using the four photoelectric conversion elements. The power is about 25 when irradiating one conventional photoelectric conversion element.
%. Therefore, as indicated by A in FIG. 10, the value of the photoelectric conversion efficiency is increased as compared with a value obtained by irradiating one conventional photoelectric conversion element (indicated by B in the figure). In this embodiment, four photoelectric conversion elements are connected in series, and the total electric output is a value obtained by adding the electric outputs of the respective photoelectric conversion elements. If the photoelectric conversion efficiency becomes higher, the electric output as a whole also increases. As described above, by using a plurality of demultiplexing means and performing photoelectric conversion with a plurality of photoelectric conversion elements, the photoelectric conversion efficiency is increased as compared with the related art, and the efficiency of the entire optical power feeding device system is improved. Becomes possible.

(Embodiment 3) FIG. 10 schematically shows a third embodiment, that is, an optical power feeding apparatus provided with three beam splitters (half mirrors) for splitting light at a ratio of 1: 1. FIG.

In FIG. 10, reference numeral 310 denotes a photoelectric conversion element which is a photoelectric conversion means for converting optical power into electric power; 320, a load device which is a device to which power generated by the photoelectric conversion element is supplied; The beam splitter 340, which is a means for splitting the obtained optical power in a one-to-one ratio, has a secondary battery, which is a means for operating the photoelectric conversion element at a constant voltage, and a zener diode connected in parallel.

Next, the operation of the sub-circuit will be described.

The optical power emitted from the optical fiber as the optical transmission path is split in two directions by the beam splitter 330 as a splitter in the sub-circuit with one-to-one optical power.
The split light is further added to the beam splitter 3.
The light passes through 30 and is split by one-to-one optical power. Finally, the four lights are split into photoelectric conversion units 3
Irradiate 10 In this way, the four photoelectric conversion units 310 (photoelectric conversion elements) are irradiated with light power of uniform intensity.

In the photoelectric conversion means 310, all the photoelectric conversion elements are connected in series, and in parallel with the photoelectric conversion elements, output voltage stabilization means 340 for stabilizing the output voltage of the photoelectric conversion means includes a secondary battery and a Zener diode. Are connected in parallel. The optical power applied to the photoelectric conversion unit 310 is converted into electric power, and is output at a voltage stabilized by the output voltage stabilization unit 340 (secondary battery and zener diode) connected in parallel with the photoelectric conversion unit 310. . When the impedance of the load device 320 is high and the load current is small, and the output current from the photoelectric conversion means 310 exceeds the load current, the excess becomes the charging current of the secondary battery 340, and the impedance of the load device 320 is low and the load When the current is large and exceeds the output current from the photoelectric conversion means 310, the excess is due to the secondary battery 340.
Supplied from

In this embodiment, the optical fiber has a core diameter of 2
It is a quartz fiber having a diameter of 00 μm and a cladding diameter of 250 μm, and is a step index type. The optical power emitted from the optical fiber is 860 mW.
10 are 215 mW each, and each photoelectric conversion unit 310 (photoelectric conversion element) has one pn
A GaAs element having a junction;
As 40, a battery in which three NiCd secondary batteries were connected in series to achieve an output voltage of 3.6 V and a Zener diode were connected in parallel was used.

The optical power emitted from the optical fiber is divided into four by the demultiplexing means, and the photoelectric conversion is performed using the four photoelectric conversion elements. Approximately 25% of the case of irradiating one photoelectric conversion element. Therefore, as indicated by A in FIG. 10, the value of the photoelectric conversion efficiency is increased as compared with a value obtained by irradiating one conventional photoelectric conversion element (indicated by B in the figure). In this embodiment, four photoelectric conversion elements are connected in series, and the total electric output is a value obtained by adding the electric outputs of the respective photoelectric conversion elements. If the photoelectric conversion efficiency becomes higher, the electric output as a whole also increases. As described above, by using a plurality of demultiplexing means and performing photoelectric conversion with a plurality of photoelectric conversion elements, the photoelectric conversion efficiency is increased as compared with the related art, and the efficiency of the entire optical power feeding device system is improved. Becomes possible.

9 and 11, the efficiency of the entire optical power feeding device system can be similarly improved by using a plurality of demultiplexing means.

[0050]

As described above, by implementing the present invention, the photoelectric conversion efficiency or the output power of the optical power feeding device is kept at or near the maximum value, and
Power can be continuously supplied to the load device at a stable output voltage. Therefore, the device is resistant to transient fluctuations of the load device occurring in the device, and is a highly reliable device capable of stably maintaining the continuous operation of the device. Further, in the optical power feeding device of the present invention, by preventing the temperature of the photoelectric conversion element from rising, it is possible to perform the photoelectric conversion with high efficiency and to extend the life of the element.

In the embodiment of the present invention, the voltage at which the photoelectric conversion element operates with high efficiency is output as it is. Of course, the voltage can be converted by a DC-DC converter or the like in accordance with the equipment serving as the load device. It is possible, and even in this case, the effect of the present invention for providing a highly efficient and highly reliable optical power feeding device is remarkable.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an optical power feeding device of the present invention.

FIG. 2 is a diagram illustrating an example of an operation time dependency of an output voltage of a photoelectric conversion element in an optical power feeding apparatus.

FIG. 3 is a diagram illustrating an example of the dependency of the photoelectric conversion element power on the photoelectric conversion element operating voltage.

FIG. 4 is a diagram illustrating an example of the dependence of photoelectric conversion efficiency on the operating voltage of a photoelectric conversion element.

FIG. 5 is a diagram illustrating an example of the dependence of the power of the photoelectric conversion element on the operation time of the optical power supply apparatus.

FIG. 6 is a diagram illustrating an example of the dependence of the efficiency of the photoelectric conversion element on the operation time of the optical power feeding apparatus.

FIG. 7 is a diagram illustrating an example of the dependence of the temperature of the photoelectric conversion element on the operation time of the optical power feeding apparatus.

FIG. 8 is a diagram illustrating an example of the dependence of the efficiency of the photoelectric conversion element on the operation time of the optical power feeding apparatus.

FIG. 9 is a schematic diagram of an optical power feeding device using a plurality of splitters of the present invention.

FIG. 10 is a diagram illustrating an example of the dependence of photoelectric conversion efficiency on light irradiation power to a photoelectric conversion element.

FIG. 11 is a schematic diagram of an optical power feeding device using a plurality of splitters of the present invention.

FIG. 12 is a schematic diagram of a conventional optical power feeding device.

FIG. 13 is a diagram illustrating an example of a relationship between an output current and an output voltage of a photoelectric conversion element.

[Explanation of symbols]

Reference Signs List 100: main circuit, 110: power supply means, 120: light emitting means, 200: optical transmission line, 300: sub-circuit, 310: photoelectric conversion means, 320: load device 330: demultiplexing means, 33
DESCRIPTION OF SYMBOLS 1 ... Demultiplexing means which divides optical power into one to two, 332 ... Demultiplexing means which divides optical power into one to three, 340 ... Output voltage stabilizing means 350 ... Backflow prevention means

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masato Mino 3-19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo F-term in Nippon Telegraph and Telephone Corporation (reference) 5F051 BA11 JA07 JA17 KA02 KA03 KA04 KA10

Claims (7)

[Claims] 1. A main circuit for generating optical power, an optical transmission line for transmitting the optical power generated by the main circuit, and a sub-circuit for receiving the optical power conveyed on the optical transmission line and converting the received optical power into electric power. In the optical power feeding apparatus provided, the main circuit includes a power supply unit, and a light emitting unit that converts power from the power supply unit into light, and the sub-circuit generates the light transmission in the main circuit. A demultiplexing unit that demultiplexes the optical power conveyed by the path into a plurality of light beams; a photoelectric conversion unit that individually converts each of the plurality of light beams demultiplexed by the demultiplexing device into electric power by a photoelectric conversion element; An optical power feeding device comprising: an output voltage stabilizing unit for stabilizing an output voltage of the conversion unit. 2. A backflow preventing means for preventing a current from flowing in a direction opposite to an output current of said photoelectric conversion means from said output voltage stabilizing means to said photoelectric conversion means. 2. The optical power feeding device according to 1. 3. The light according to claim 1, wherein said output voltage stabilizing means stabilizes the output voltage of said photoelectric conversion means so that the output power from said photoelectric conversion means is maximized. Power feeding device. 4. The optical power feeding device according to claim 1, wherein the demultiplexing unit demultiplexes the light so that the photoelectric conversion efficiency of the photoelectric conversion unit is maximized. 5. The optical power feeding device according to claim 1, wherein one or a plurality of secondary batteries are connected in series as said output voltage stabilizing means. 6. The output voltage stabilizing means, wherein one or a plurality of secondary batteries are connected in series and a Zener diode is connected in parallel. 5. The optical power feeding device according to claim 3, or 4. 7. The apparatus according to claim 1, wherein one or a plurality of beam splitters are used as said demultiplexing means.
7. The optical power feeding device according to 2, 3, 4, 5, or 6.