JP2000324727A - Power feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the stable continuous operation of a load device by equipping a power feeder with accumulating parts which supplementarily supply a load device with accumulated power, in case that the power consumption of the load device is over the power converted by a light receiving means. SOLUTION: For this optical power feeder, when light is generated from a laser element 2 by the power supplied from a power source 1 in a main circuit 10, this light is carried to the side of a sub circuit 20 via an optical fiber 4. Then, the sub circuit 20 supplies the power to a load device 5 after having converted this light into electric energy with a photoelectric converting element 3, but when the supplied power is larger than the power consumption of the load device 5, excessive power is accumulated and charged in accumulating parts 6. Moreover, when the power consumption is over the supplied power, the power accumulated in the accumulating parts 6 are discharged, and it is supplied to the load device 5, thereby supplementing the amount of shortage of the power supplied from the photoelectric converting element 3. As a result, the single power feeder can maintain the continuous operation of the load device stably by itself.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device, and more particularly to a power supply device for supplying power in the form of light energy from a main circuit to a sub-circuit and supplying power from a sub-circuit to a load device.

[0002]

2. Description of the Related Art There is known a power supply device (hereinafter, simply referred to as an optical power supply device) including a sub-circuit for supplying power to a load device and a main circuit for supplying power to the sub-circuit in the form of optical energy. Have been. This optical power feeding apparatus is used for a reason such as to prevent an adverse effect such as an electric leakage or an electromagnetic induction noise caused by a feeding line being conductive in a feeding method using an electric wire (or a cable), or for a remote place or a remote place. It is used as a power supply method capable of electrically insulating a place where power cannot be taken, such as underwater, and a device installed in a chemical plant or the like. FIG. 7 is a block diagram showing a schematic configuration of a conventional optical power feeding device. As shown in FIG. 1, the optical power feeding apparatus basically includes a main circuit 100 for generating optical energy, an optical fiber (optical transmission line) 4 for transporting optical energy, and optical energy. 5 for supplying power to the sub-circuit 5. The main circuit 100 includes a power supply (power supply unit) 1 and a laser element (light emitting unit) 2 that generates optical energy with the power supplied from the power supply 1. The sub-circuit 200
It has a photoelectric conversion element (light receiving means) 3 for converting light energy conveyed via the optical fiber 4 into electric energy. As described above, in the conventional optical power feeding device, in the main circuit 100, the laser element 2 generates optical energy with the power supplied from the power supply 1, and this optical energy is transmitted to the sub-circuit 200 through the optical fiber 4. The power is supplied to the load device 5 after the transmitted light energy is converted into electric power by the photoelectric conversion element 3 on the sub-circuit 200 side.

[0003]

As described above, in the conventional optical power feeder, the optical energy supplied from the main circuit 100 is converted into electric power by the sub-circuit 200 and then supplied to the load device 5. . Recent electronic devices include, for example,
Many devices require a peak current several to ten times the average current consumption when the device is started up or during intermittent operation. When a device whose power consumption fluctuates with time is connected as the load circuit 5 of the sub-circuit 200, if the power consumption of the load device 5 exceeds the supply power even in an extremely short time,
The load device 5 stops due to power shortage. in this way,
In the conventional optical power feeding device, a load device 5 whose power consumption fluctuates with time is connected to the sub-circuit 200, and when the power consumption of the load device 5 exceeds the supplied power, the load device 5 There was a problem that continuous operation could not be maintained and reliability was low. In order to prevent such a stop of the load device 5, an optical power supply device having a large output capacity capable of supplying the maximum power consumption of the load device 5 or a parallel connection operation of a plurality of optical power supply devices is required. As a result, the output capacity of the optical power feeding device or the number of optical power feeding devices increases, resulting in a problem that the cost increases. The present invention has been made in order to solve the problems of the related art, and an object of the present invention is to provide a single power supply device even when power consumption of a load device temporarily exceeds supply power. An object of the present invention is to provide a highly reliable and economical power supply device capable of stably maintaining continuous operation of a load device. The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0004]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows. That is, the present invention provides a main circuit that converts electric energy into optical energy, an optical transmission line that carries the optical energy from the main circuit, and receives the optical energy from the optical transmission line and supplies power to a load device. A power supply unit, and a light emitting unit that converts electric energy supplied from the power supply unit into light energy, wherein the sub-circuit is configured to receive the received light. A light receiving means for converting energy into electric energy, and accumulating the power converted by the light receiving means; and the power stored when the power consumption of the load device is equal to or greater than the power converted by the light receiving means. And a power storage component for supplementarily supplying the load device to the load device. Further, the invention is characterized in that the power storage component is a storage battery. Further, the present invention provides the power storage component,
It is a capacitor. Further, the present invention is characterized in that the power storage component is an electric double layer capacitor.

[0005]

Embodiments of the present invention will be described below in detail with reference to the drawings. In all the drawings for describing the embodiments, components having the same functions are denoted by the same reference numerals, and repeated description thereof will be omitted.

[First Embodiment] FIG. 1 is a block diagram showing a schematic configuration of an optical power feeding apparatus according to a first embodiment of the present invention. The optical power feeder of the present embodiment also has a main circuit 10 for generating optical energy, an optical fiber (optical transmission line) 4 for transporting optical energy, and a sub-circuit for receiving optical energy and supplying power to a load circuit 5. And a circuit 20. The main circuit 10 includes a power source (power supply means) as in the conventional circuit.
1 and a laser element (light emitting means) 2 for generating optical energy with electric power supplied from a power supply 1. The sub-circuit 20 is a photoelectric conversion element (light receiving means) for converting light energy conveyed via the optical fiber 4 into electric energy.
3 and a power storage component 6. This power storage component 6
The power converted by the photoelectric conversion element 3 is stored, and when the power consumption of the connected load device 5 exceeds the power converted by the photoelectric conversion element 3, the stored power is transmitted to the load device 5. Load device 5 by supplementary supply
Has the function of always supplying the required power. next,
The operation of the optical power feeding device according to the present embodiment will be described. In the main circuit 10, light is generated from the laser element 2 by the power supplied from the power supply 1. This light is transmitted through the optical fiber 4
Through the sub-circuit 20. In this case, the light output from the laser element 2 is light for supplying electric power to the sub-circuit 20 side, so this light is not light having an output of about 10 mW used for ordinary optical communication or the like. , 100m
It is a light with a large output of about W or more. Subcircuit 2
Numeral 0 converts this light into electric energy by the photoelectric conversion element 3 and then supplies the electric power to the load device 5. Here, when the power consumption of the load device 5 fluctuates with time, the power storage component 6 operates as follows. (1) When the power supplied from the photoelectric conversion element 3 is larger than the power consumption of the load device 5, excess power not consumed by the load device 5 is charged and stored in the power storage component 6. (2) Conversely, when the power consumption of the load device 5 exceeds the supply power supplied from the photoelectric conversion element 3, the power stored in the power storage component 6 is discharged and the supply power supplied from the photoelectric conversion element 3 Is supplied to the load device 5. As described above, even when the power consumption of the load device 5 fluctuates with time, the optical power supply device of the present embodiment can
The power required by the load device 5 can be constantly supplied to the load device 5, and the continuous operation of the load device 5 can be stably maintained. Therefore, according to the present embodiment, even if the load device 5 has a large load fluctuation and the maximum power consumption exceeds the supply power supplied from the photoelectric conversion element 3, the load can be reduced by a single power supply device. The continuous operation of the device 5 can be stably maintained, and a highly reliable and economical power supply device can be provided.

Hereinafter, an example of this embodiment will be described. [Embodiment 1] In this embodiment, a storage battery is used as the power storage component 6. In the present embodiment, when the power consumption of the load device 5 fluctuates with time, the following operation is performed. (1) When the power supplied from the photoelectric conversion element 3 is larger than the power consumption of the load device 5, excess power not consumed by the load device 5 is charged to the storage battery and stored. (2) Conversely, the power consumption of the load device 5 is
When the power exceeds the power supplied from the photoelectric conversion element 3, the power stored in the storage battery is discharged to compensate for the shortage of the power supplied from the photoelectric conversion element 3, and the power required by the load device 5 is always reduced. Can be supplied. Accordingly, even in the present embodiment, even if the load device 5 has a large load fluctuation and the maximum power consumption exceeds the supply power supplied from the photoelectric conversion element 3, the load device 5 can be replaced by a single power supply device. Continuous operation can be stably maintained, and a highly reliable and economical power supply device can be provided.

[Embodiment 2] In this embodiment, an electric storage device is used as the electric storage component 6. Also in this embodiment, as in the first embodiment, when the power consumption of the load device 5 fluctuates with time,
It works as follows. (1) When the power supplied from the photoelectric conversion element 3 is larger than the power consumption of the load device 5, the excess power not consumed by the load device 5 is charged and stored in the battery. (2) Conversely, the power consumption of the load device 5 is
When the power exceeds the power supplied from the storage device, the power stored in the battery is discharged to compensate for the shortage of the power supplied from the photoelectric conversion element 3, and the power required by the load device 5 is constantly reduced. Can be supplied. Accordingly, even in the present embodiment, even if the load device 5 has a large load fluctuation and the maximum power consumption exceeds the supply power supplied from the photoelectric conversion element 3, the load device 5 can be replaced by a single power supply device. Continuous operation can be stably maintained, and a highly reliable and economical power supply device can be provided. In general, as shown in FIG. 2, an equivalent circuit of a capacitor is represented by a series circuit of a resistor (equalized series resistance: Rs) and a capacitor (C). Therefore, when the power consumption of the load device 5 fluctuates rapidly over time, it is more advantageous to use a capacitor having a small equivalent series resistance (Rs) in order to improve the followability of the discharge characteristics. In addition, the capacitor
Since there is no limiting factor such as characteristic deterioration or repeated life due to repeated charging and discharging as seen in a storage battery, the function can be maintained semipermanently. Therefore, there is no need for maintenance costs such as periodic replacement or the cost of replacement parts as in the case of using a storage battery, so that the power supply device is more economical.

[Embodiment 3] In this embodiment, an electric double layer capacitor is used as the electric storage component 6. Further, as the load device 5, a device having a large fluctuation in power consumption and including a motor was used. FIG. 3 shows an example of a temporal change in the power consumption of the load device 5. The average value of the power consumption of the load device 5 used in this embodiment is about 150 mW, but about 900 to 1000 mW at the maximum (motor driving) and about 75 m at the minimum.
mW and the maximum value is 10 times or more the minimum value, and the fluctuation range is extremely large. In addition, a laser element (light emitting means) 2
As an AlGaAs semiconductor laser (wavelength: 810n)
m, output: 750 mW) to a photoelectric conversion element (light receiving means)
3 as a GaAs photoelectric conversion element (diameter: 3 mm, output: 2 V); and as an optical fiber (optical transmission line) 4, a quartz optical fiber (core diameter: 200 μm, SI type, NA = 0.
2, length: 200 m). Furthermore, as an electric double layer capacitor, the capacitance (C: 2F) and the equivalent series resistance (R
s: 30 mΩ). The output power of the photoelectric conversion element 3 (the power supplied from the photoelectric conversion element 3) is about 2
The power consumption is constant at 00 mW, which sufficiently satisfies the necessary condition of “must be equal to or more than the average value of the load power consumption” described later. The rated operating voltage of the load device 5 is 1.
The output current at 5V is about 130mA. That is, the maximum power consumption of the load device 5 is about five times larger than the supply power that can be constantly supplied from the photoelectric conversion element 3. As a result of using the optical power feeding device of the present embodiment for the operation of the load device 5 described above, the load device 5 started normally and a stable continuous operation was realized. In addition, it was confirmed that the stable continuous operation was still maintained after 10 hours or more while the load device 5 was normally operated.

FIG. 4 shows the time dependence of the output current of the photoelectric conversion element 3, the current consumed by the load device 5, and the current flowing through the electric double layer capacitor during the steady operation. Here, as for the current flowing through the electric double layer capacitor, the plus side indicates charging (that is, the polarity in which power is accumulated in the electric double layer capacitor), while the minus side discharges (that is, power from the electric double layer capacitor). (Polarity supplied). FIG.
As can be seen from FIG. 3, the output current from the photoelectric conversion element 3 is substantially constant, and when the current consumption of the load device 5 is larger than the output current of the photoelectric conversion device 3, the electric current is transferred from the electric double layer capacitor to the load device 5. On the other hand, an electric current is supplied supplementarily. That is, the electric double layer capacitor plays a role as an auxiliary power supply for supplying the stored power to the load device 5 following the load fluctuation of the load device 5, and its operation is particularly complicated. No external control or charging circuit is required. The same load device 5 was operated by a conventional optical power feeding device not including an electric double layer capacitor, but the power required for starting could not be supplied. 5 could not even be started. The condition of the device connected as the load device 5 is that the average value of the power consumption is required to be equal to or less than the power supplied from the photoelectric conversion element 3. Furthermore, when the power consumption of the load device 5 exceeds the supply power supplied from the photoelectric conversion element 3 when the power consumption of the load device 5 fluctuates, the shortage of power in the load device 5 and the continuous time It is necessary to appropriately select the capacity of the electric double layer capacitor and the value of the equivalent series resistance depending on the length. When the power consumption of the load device 5 fluctuates rapidly in time as in this embodiment, an electric double layer capacitor having a small equivalent series resistance value is used in order to improve the followability of the discharge characteristics. Is more advantageous.

Next, a method of setting the capacitance of the electric double layer capacitor and the equivalent series resistance will be described. FIG.
FIG. 4 is a diagram schematically illustrating the time dependency of the current consumption at the time of startup when the load device 5 of the present embodiment consumes the maximum power.
Here, assuming that the output current of the photoelectric conversion element 3 is slightly less than 100 mA, of the current consumption of the load device 5, 1
It can be seen that it is only necessary to supplementarily supply a current exceeding 00 mA (total charge amount integrated over time) from the electric double layer capacitor. This can be expressed by the following equation (1).

[0012]

(Equation 1)

Here, ΔQ is the accumulated charge amount, Ic is the current consumption of the load device 5, Io is the output current of the photoelectric conversion element 3, and in the case of FIG. 5, ΔQ is 1.25 coulomb. Therefore, the electricity 2 for storing the minimum necessary charge amount
The capacitance of the multilayer capacitor is expressed by the following expression (2), which represents the relationship among the capacitance (C) of the capacitor, the amount of accumulated charge (ΔQ), and the voltage (V; operating voltage 1.5 V).
(Q = 1.25, V = 1.5V), and the capacitance of the electric double layer capacitor is obtained, a value of 0.84F is obtained. Therefore, a setting condition is obtained that an electric double layer capacitor having a capacity equal to or larger than this value should be used.

[0014]

C = ΔQ / V (2) On the other hand, the terminal voltage of the electric double layer capacitor viewed from the load device 5 side ( Vt) is a charging voltage (V1), an equalizing series resistance (Rs), a consumption current (Ic) of the load device 5, an output current (Io) of the photoelectric conversion element 3, a current supply time (t), and a capacitor capacity (C). ) Etc. are represented by the following (3).

[0015]

Vt = V1− {Rs · (Ic−Io)} − {(Ic−Io) · t / C} (3) Load Depending on the device 5, there is a device in which a minimum required voltage value for maintaining operation is determined. In the case where such a device is connected as the load device 5, in Expression (3), (Vt) should not be lower than the minimum voltage (1 V in the present embodiment) required to maintain the continuous operation of the load device 5. , It is necessary to set the values of the capacitor capacity (C) and the equivalent series resistance (Rs). Here, the equivalent series resistance (Rs) is set to 6
Assuming 0 mΩ, in order to satisfy Vt ≧ 1, the above-mentioned values (Ic = 600 mA, Io = 10
0 mA, Rs = 60 mΩ, t = 2.5, V1 = 2 V), a value of C ≧ 1.29F is obtained.
Therefore, a second setting condition that an electric double layer capacitor having a capacity equal to or larger than this value may be used is obtained. Since the capacitance of the electric double layer capacitor actually used needs to satisfy both of the expressions (2) and (3), finally, in the case of this embodiment, the equivalent series resistance ( If Rs) is 60 mΩ or less, the setting condition is C ≧ 1.29F. For the above reasons, in this embodiment, an electric double layer capacitor having a value of capacitance (C): 2F and equivalent series resistance (Rs): 30 mΩ is used. FIG. 6 shows the relationship between the capacitance (C) of the electric double layer capacitor and the discharge current qualitatively using the equivalent series resistance (Rs) as a parameter. When the discharge current increases, the voltage drop increases, so that the capacity (C) tends to decrease. The decrease in capacity due to the increase in discharge current depends on the resistance value of the equivalent series resistance (Rs), and the greater the resistance value of the equivalent series resistance (Rs), the more remarkable the decrease in capacity. That is, it can be said that it is more effective to use an electric double-layer capacitor having a small equivalent series resistance (Rs) for the application of large current discharge. However, the resistance value of the equivalent series resistance (Rs) of the electric double layer capacitor depends on the material and the element structure, and therefore cannot always be selected on purpose. Generally, as the capacitance (C) increases, the resistance value of the equivalent series resistance (Rs) tends to decrease. Therefore, in order to reduce the resistance value of the equivalent series resistance (Rs), a method of using an electric double layer capacitor having an unnecessarily large capacity may be considered. However, as the capacitance (C) increases, the initial charge of the electric double layer capacitor increases. It is necessary to pay attention to such an adverse effect that the time required for the process becomes long and the element becomes large.

As described above, even in the present embodiment, even if the load device 5 has a large load fluctuation and the maximum power consumption exceeds the power supplied from the photoelectric conversion element 3, the single power supply device can be used. Thus, the continuous operation of the load device 5 can be stably maintained, and a highly reliable and economical power supply device can be provided. In addition, electric double layer capacitors
Since the volume energy density is higher than that of a normal power storage device, a smaller and lighter optical power feeding device can be configured. In addition,
In each of the above embodiments, a storage battery, a storage battery,
Alternatively, the case of using an electric double layer capacitor has been described, but the present invention is not limited to this, and any power storage component of the present invention may be used as long as it can store or supply a necessary amount of power. In addition, not only one kind of power storage component, but a plurality of types may be used in combination. For example, if a storage battery and an electric double layer capacitor are combined, the burden ratio of the power supplied from the main circuit 10 at the time of power shortage is reduced, so that the device has higher reliability. Furthermore, the sub-circuit 20
Needless to say, the present device can be improved to a device that intermittently supplies power to the side or a device that can carry an optical signal between the main circuit 10 and the sub-circuit 20 as well as one-sided power supply. . As described above, the invention made by the inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and can be variously modified without departing from the gist of the invention. Of course, it is.

[0017]

The effects obtained by typical ones of the inventions disclosed in the present application will be briefly described as follows. (1) According to the present invention, even when the power consumption of the load device exceeds the power transferred from the main circuit and converted, it is possible to always supply the power required by the load device. (2) According to the present invention, even if a load device has a large load fluctuation and the maximum power consumption of which exceeds the power supplied from the photoelectric conversion element, the load device can be continuously connected with a single power supply device. The operation can be stably maintained, and a highly reliable and economical power supply device can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a power supply device according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing an equalizer circuit of a battery used as a power storage component of the present embodiment.

FIG. 3 is a graph illustrating an example of a temporal change in power consumption of a load device connected to the optical power feeding device according to the present embodiment.

FIG. 4 shows the time dependence of the output current of the photoelectric conversion element, the consumption current of the load device, and the current flowing through the electric double layer capacitor in the third embodiment of the optical power feeding device of the present embodiment during a steady operation. It is a graph.

FIG. 5 is a diagram schematically illustrating the time dependence of current consumption at startup when the load device of Example 3 of the optical power supply device of the present embodiment consumes maximum power.

FIG. 6 is a graph qualitatively showing a relationship between a capacity of an electric double layer capacitor used in Example 3 of the optical power feeding device of the present embodiment and a discharge current by using an equivalent series resistance as a parameter.

FIG. 7 is a block diagram illustrating a schematic configuration of a conventional power supply device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Power supply, 2 ... Laser element, 3 ... Photoelectric conversion element, 4 ...
Optical fiber, 5: load device, 6: power storage component, 10, 10
0: Main circuit, 20, 200: Sub circuit, C: Capacitance, Rs:
Equalizing series resistance.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mikio Yamazaki 3-19-2 Nishishinjuku, Shinjuku-ku, Tokyo F-term in Nippon Telegraph and Telephone Corporation 5F051 AA08 JA17 5F089 AA10 AB20 AC10 CA21 GA10 5G003 AA01 BA01 CC01 DA06 DA18

Claims (4)

[Claims] 1. A main circuit for converting electric energy to optical energy, an optical transmission line for transmitting optical energy from the main circuit, and receiving optical energy from the optical transmission line to supply power to a load device. In the power supply device including a sub-circuit, the main circuit includes: a power supply unit; and a light-emitting unit configured to convert electric energy supplied from the power supply unit into optical energy. A light receiving means for converting the power into electric energy, and storing the power converted by the light receiving means, and when the power consumption of the load device is equal to or more than the power converted by the light receiving means, the stored power is A power supply device, comprising: a power storage component for supplementarily supplying the load device. 2. The power supply device according to claim 1, wherein the power storage component is a storage battery. 3. The power supply device according to claim 1, wherein the power storage component is a power storage device. 4. The power supply device according to claim 1, wherein the power storage component is an electric double layer capacitor.