JP2024023028A - Natural energy storage device, natural energy wireless communication device, and power generation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently store generated power in a secondary battery.

SOLUTION: A natural energy storage device 50 includes a plurality of DC power sources 30,35 being combinations of natural energy power generating apparatuses 10,20 and secondary batteries 12,22 that charge power generated by the natural energy power generating apparatuses 10,20, respectively. The secondary battery 12 of the DC power source 30 which generates more power is connected to a load 60, whereas the secondary battery 22 of the DC power source 35 which generates less power is not connected to the load 60. In the natural energy power generating apparatuses 10,20, switching between solar cells and wind power generation facilities is performed.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a natural energy storage device that stores natural energy such as sunlight or wind power in a secondary battery, a natural energy wireless communication device, and a power generation method.

There is a technology that uses solar cells and secondary batteries to wirelessly transmit sensor information such as water level, flow velocity, bridge vibration, and captured images to remote locations, regardless of day or night. For example, Patent Document 1 discloses a water level gauge that performs measurement and wireless transmission at predetermined time intervals (for example, 30 minutes or 1 hour).

JP2018-72280A (Paragraph 0046,0048)

In cases where captured images, not just water levels, are periodically transmitted wirelessly, when the imaging cycle is short, the amount of power consumed by the imaging camera is greater than the amount of power generated by solar power generation, and the secondary battery There was a problem that the stored energy of the battery decreased.

The present invention has been made to solve these problems, and provides a natural energy power storage device, a natural energy wireless communication device, and a power generation method that can efficiently store generated power in a secondary battery. The purpose is to

In order to achieve the above object, a first invention provides a natural energy storage device including a plurality of DC power sources that combine a natural energy power generation device and a secondary battery for charging the power generated by the natural energy power generation device. The secondary battery of the DC power source that generates a large amount of power is connected to a load, and the secondary battery of the DC power source that generates a small amount of power is disconnected from the load. .

Further, a second invention is a natural energy power storage device that combines a natural energy power generation device and a secondary battery that charges the generated power generated by the natural energy power generation device, wherein the natural energy power generation device includes a solar battery and a secondary battery that charges the generated power generated by the natural energy power generation device. It is a combination with a wind power generator, and is characterized in that the secondary battery is charged by the solar cell or the wind power generator, whichever generates more power.

According to the present invention, generated power can be efficiently stored in a secondary battery.

1 is a configuration diagram of a natural energy wireless communication device that is an embodiment of the present invention. FIG. 3 is a configuration diagram of a first power generation unit. It is a block diagram of a 2nd power generation unit. 1 is a flowchart illustrating the operation of a natural energy wireless communication device according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that each figure is merely shown schematically to the extent that the embodiments can be fully understood. Further, in each figure, common or similar components are denoted by the same reference numerals, and redundant explanation thereof will be omitted.

(Embodiment)
FIG. 1 is a configuration diagram of a natural energy wireless communication device according to an embodiment of the present invention.
Natural energy wireless communication device 100 includes a natural energy storage device 50 and a wireless sensor device 60.
The natural energy power storage device 50 is a DC power source (for example, , a first DC power source 30, a second DC power source 35), and a secondary battery (for example, the secondary battery 12) of the DC power source (for example, the first DC power source 30) that generates a large amount of power. A secondary battery (e.g., secondary battery 22) of a DC power source (e.g., second DC power source 35) that is connected to a load (wireless sensor device 60) and generates less power is connected to the load (wireless sensor device 60). The first feature is that it is disconnected. Thereby, the first DC power source 30, which generates a large amount of power, charges the secondary battery 12 and supplies power to the load. On the other hand, the second DC power source 35, which generates less power, does not supply power to the load. Note that the first DC power source 30 charges the secondary battery 12 and the second DC power source 35 charges the secondary battery 22 regardless of the magnitude of the generated power.

Further, each power generation unit (first power generation unit 10, second power generation unit 20) is configured by combining a plurality of types of natural energy power generation devices. Power generating equipment that generates a large amount of power charges the secondary batteries 12 and 22 and supplies DC power to the load (wireless sensor device 60), while power generating equipment that generates a small amount of power charges the secondary batteries 12 and 22. It is configured to only do

The first power generation unit 10 includes a first solar cell 1a (FIG. 2) and a first wind power generator 2a (FIG. 2) as another power generation device, and generates DC power with a voltage V1 and an output current I1. The second power generation unit 20 includes a second solar cell 1b (FIG. 3) and a second wind power generator 2b (FIG. 3) as another power generation device, and generates DC power with a voltage V3 and an output current I2. That is, the first power generation unit 10 and the second power generation unit 20 store natural energy (solar energy, wind energy, etc.) in the secondary batteries 12 and 22. In addition, when the swept area A [m ² ], the wind speed v [m/s], and the air density ρ [kg/m ³ ], the kinetic energy W [J] due to wind power is W = (1/2) mv ² =(1/2) ^ρAv3 . This energy (power) is stored in the secondary batteries 12 and 22.

In the first power generation unit 10, the one that generates more power from the first solar cell 1a and the first wind power generator 2a charges the secondary battery 12 and supplies DC power to the load, and the one that generates less power charges the secondary battery 12 and supplies DC power to the load. The secondary battery 12 is charged, but DC power is not supplied to the load. Similarly, in the second power generation unit 20, the second solar cell 1b and the second wind power generator 2b, which generates more power, charges the secondary battery 22 and supplies DC power to the load, so that the generated power is increased. The smaller one charges the secondary battery 22 but does not supply DC power to the load.

In FIG. 1, the natural energy storage device 50 includes a first DC power source 30, a second DC power source 35, two voltage measuring units 40 and 41, a switch SW1, and a capacitor 45. There is. The first DC power source 30 includes the first power generation unit 10 described above, a generated current monitor 11, and a secondary battery 12. The second DC power source 35 includes the second power generation unit 20 described above, a generated current monitor 21, and a secondary battery 22.

The secondary batteries 12 and 22 are, for example, nickel-metal hydride assembled batteries with a nominal voltage of Vn, in which single cells with a nominal voltage of 1.2 V are connected in series and parallel. The secondary batteries 12 and 22 have a rated capacity C [Ah], and are charged with a constant current of charging current K·C [Ah]/1h=K·C [A] to prevent overcurrent. Further, the secondary batteries 12 and 22 have a property that the secondary battery charging power (=generated power) increases when the load current is not flowing than when the load current is flowing. Therefore, in this embodiment, a plurality of secondary batteries 12 and 22 are provided, and one of the secondary batteries is only charged and not discharged.

Furthermore, the secondary batteries 12 and 22 have a characteristic that charging is not performed with a minute current, but charging is started with a specific current (minimum charging current). Further, this minimum charging current is smaller for a small capacity secondary battery than for a large capacity secondary battery. Therefore, when a plurality of secondary batteries 12, 22 are used as in this embodiment, rather than using a single secondary battery whose capacity is the sum of the rated capacity C of each of the secondary batteries 12, 22. Charging can be performed even with a small amount of generated power. Note that the secondary batteries 12 and 22 are not limited to nickel-metal hydride assembled batteries, but may also be lithium ion batteries or the like.

The generated current monitors 11 and 21 detect output currents I1 and I2 (see FIG. 3) of the first power generation unit 10 and the second power generation unit 20. Note that the output current I1 of the first power generation unit 10 is equal to the sum (I3+I4) of the charging current I3 flowing to the secondary batteries 12 and 22 and the load current I4 flowing to the load (wireless sensor device 60) via the switch SW1. .

Voltage measurement units 40 and 41 measure voltages V2 and V4 of secondary batteries 12 and 22, respectively. The switch SW1 is a three-contact switch. Contact a is connected to the first DC power source 30, contact c is connected to the second DC power source 35, and contact b is connected to the first DC power source 30 and the second DC power source 35. It is in an OFF state where it is not connected to anything.

The capacitor 45 is maintained at the voltage of either the first DC power source 30 or the second DC power source 35, and even if the switch SW1 is in the OFF state of the contact b, the capacitor 45 is connected to the load (wireless sensor device) for a certain period of time. 60).

The wireless sensor device 60 includes a sensor section 61, a control section 65, and a wireless section 62, and wirelessly transmits information from various sensors to the outside. The sensor section 61 includes one or a combination of an imaging device, a water level gauge, a vibration sensor, etc. (not shown). The imaging device, for example, images the water level of a river periodically (for example, every minute or every five minutes). A water level gauge, for example, periodically observes the water level of a river. The vibration sensor detects, for example, vibrations of a bridge spanning a river.

The wireless unit 62 transmits data detected by the sensor unit 61 (captured images, water level data, vibration data, etc.) to other natural energy wireless communication devices (not shown) and a server (not shown) using LTE (Long Term Evolution). to communicate wirelessly. The wireless unit 62 also communicates with a wireless base unit (not shown) that uses sub-GHz band wireless. Further, the wireless unit 62 of the own device receives data (captured images, water level data, vibration data, etc.) from another natural energy wireless communication device (not shown). In other words, the natural energy wireless communication device 100 functions as a zero energy gateway. The control unit 65 is a CPU (Central Processing Unit) that controls the sensor unit 61, the wireless unit 62, and the natural energy storage device 50.

FIG. 2 is a configuration diagram of the first power generation unit 10, and FIG. 3 is a configuration diagram of the second power generation unit 20.
The first power generation unit 10 (FIG. 2) includes a first solar cell 1a, a maximum power point tracking control section 3a, a constant voltage circuit with overcurrent limiting function 4a, a first wind power generator 2a, and a rectifying and smoothing circuit 5. , a maximum power point follow-up control section 3b, a constant voltage circuit with overcurrent limiting function 4b, and a switch SW2. Similarly, the second power generation unit 20 (FIG. 3) includes a second solar cell 1b, a maximum power point tracking control section 3c, a constant voltage circuit with overcurrent limiting function 4c, a second wind power generator 2b, and a rectifier. It is configured to include a smoothing circuit 5, a maximum power point follow-up control section 3d, a constant voltage circuit with overcurrent limiting function 4d, and a switch SW3.

The first solar cell 1a and the second solar cell 1b convert solar energy into DC power with a voltage V1 and an output current I1. The maximum power point tracking control units 3a, 3c vary the voltages V5, V6 of the first solar cell 1a and the second solar cell 1b, and output a current that provides the maximum power. The constant voltage circuits 4a and 4c with overcurrent limiting function step up or step down the output voltages V5 and V6 of the first solar cell 1a and the second solar cell 1b controlled by the maximum power point tracking control sections 3a and 3c, and Next, charge the batteries 12, 22 (FIG. 1) to the nominal voltage Vn. Further, the constant voltage circuits 4a and 4c with an overcurrent limiting function limit the output currents I1 and I2 by a limit current setting value IL so as not to charge the secondary batteries 12 and 22 (FIG. 1) with an overcurrent.

Note that if the output current I6 of the first solar cell 1a and the second solar cell 1b is less than the limiting current IL, the constant voltage circuit with overcurrent limiting function 4a does not perform current limiting. At this time, the output current I6=I1=(power at maximum power point/voltage V2 of the secondary battery 12 (FIG. 1)). In other words, the output power at the maximum power point of the natural energy power generation equipment (first solar cell 1a, second solar cell 1b, first wind power generator 2a, second wind power generator 2b) ×I1) divided by the voltage V2 of the secondary batteries 12, 22 (output current I1) is smaller than the allowable charging current IAL of the secondary batteries 12, 22 (IAL>Limited current setting value IL) .

The first wind power generator 2a and the second wind power generator 2b are rotating electrical machines connected to a propeller, and generate electricity using wind power. Wind power generation is useful at night, during rainy weather, and when solar cells are installed at the bottom of bridges and sunlight is difficult to reach.

The rectifying and smoothing circuit 5 includes a diode and an electrolytic capacitor (not shown), and converts the AC voltage output from the first wind power generator 2a and the second wind power generator 2b into a DC voltage. The maximum power point tracking control units 3b and 3d vary the output voltage of the rectifying and smoothing circuit 5 to output a current that provides the maximum power.
The maximum power point follow-up control units 3b and 3d use the voltage fluctuation of the rectifying and smoothing circuit 5 to output a current that provides the maximum power.
The constant voltage circuits 4b and 4d with overcurrent limiting function step up or step down the output voltage of the first wind power generator 2a and the second wind power generator 2b controlled by the maximum power point tracking control sections 3b and 3d, and Charge the batteries 12, 22 (FIG. 1) to the nominal voltage Vn.

The switch SW2 is a switch that switches between the output voltage of the constant voltage circuit with overcurrent limiting function 4a and the output voltage of the constant voltage circuit with overcurrent limiting function 4b. In other words, the switch SW2 switches between the power generated by the first solar cell 1a and the power generated by the first wind power generator 2a.
The switch SW3 is a switch that switches between the output voltage of the constant voltage circuit with overcurrent limiting function 4c and the output voltage of the constant voltage circuit with overcurrent limiting function 4d. In other words, the switch SW3 switches between the power generated by the second solar cell 1b and the power generated by the second wind power generator 2b.

FIG. 4 is a flowchart for explaining the operation of the natural energy wireless communication device 100 according to the embodiment of the present invention. This flow starts when the power is turned on or reset.
Voltage measurement units 40 and 41 (FIG. 1) measure the voltage of each secondary battery 12 and 22 (S1). After the process in S1, the control unit 65 (FIG. 1) determines whether the voltages of both the secondary batteries 12 and 22 are below the threshold value (S2). If the voltages of both secondary batteries 12 and 22 are below the threshold (YES in S2), the control unit 65 sets the switch SW1 to contact b to turn it off (S3). As a result, the wireless sensor device 60 will not start up, but the secondary batteries 12 and 22 will continue to be charged.

On the other hand, if the voltage of either of the secondary batteries 12, 22 exceeds the threshold (NO in S2), the control unit 65 compares the voltages of the secondary batteries 12, 22 (S4). If the voltage of the secondary battery 12 is higher than the voltage of the secondary battery 22, the control unit 65 sets the switch SW1 to contact a to set the path to path 1 (S5). After the processing in S5, the control unit 65 determines whether the generated current measured by the generated current monitor 11 (FIG. 1) is less than or equal to a threshold value (S6). If the generated current is below the threshold (YES in S6), the control unit 65 switches the switch SW2 (FIG. 2) (S7). That is, if the generated current of the first solar cell 1a is below the threshold value, the secondary battery 12 is charged by the first wind power generator 2a. Conversely, if the generated current of the first wind power generator 2a is below the threshold value, the secondary battery 12 is charged by the first solar cell 1a. After the process in S7 or when the generated current exceeds the threshold value in S6 (NO in S6), the control unit 65 returns the process to S1 and measures the voltages of the secondary batteries 12 and 22.

On the other hand, when the voltage of the secondary battery 22 is higher than that of the secondary battery 12 in S4, the control unit 65 sets the switch SW1 (FIG. 1) to the contact point c to set the path to path 2 (S8). After the processing in S8, the control unit 65 determines whether the generated current measured by the generated current monitor 21 (FIG. 1) is less than or equal to a threshold value (S9). If the generated current is below the threshold (YES in S9), the control unit 65 switches the switch SW3 (FIG. 2) (S10). That is, if the generated current of the second solar cell 1b is below the threshold value, the secondary battery 22 is charged by the second wind power generator 2b. Conversely, if the generated current of the second wind power generator 2b is below the threshold value, the secondary battery 22 is charged by the second solar cell 1b. After the process in S10 or when the generated current exceeds the threshold value in S9 (NO in S9), the control unit 65 returns the process to S1 and measures the voltages of the secondary batteries 12 and 22.

Conventional charging/discharging systems discharge to the load while charging the secondary battery. In the natural energy power storage device 50 of the present embodiment, a discharge path (for example, path 1 (FIG. 1) when switch SW1 is set to contact a) for charging the secondary battery and discharging from the secondary battery to the load is provided. , and a separate path (for example, path 2 (FIG. 1) when switch SW1 is set to contact a) that is a charging-only path. As a result, the charging efficiency and charging amount of the secondary battery 22 on the path 2 through which no load current is flowing increases. Furthermore, since the natural energy power storage device 50 includes the plurality of secondary batteries 12 and 22, the minimum charging current is smaller than when using a single secondary battery whose capacity is the sum of the capacities of the respective secondary batteries. Since the current value is small, charging can be performed even with a small amount of generated power.

In addition, the natural energy power storage device 50 of the present embodiment includes other power generation devices (for example, a first wind power generator 2a, a second wind power generator 2b) different from the solar cells (the first solar cell 1a, the second solar cell 1b). By providing a charging line from the battery, it becomes possible to charge the battery at night or in the rain. Therefore, the amount of charge of the secondary batteries 12, 22 increases, leading to an increase in communication frequency and sensor information amount.

(Modified example)
The present invention is not limited to the embodiments described above, and various modifications such as those described below are possible.
(1) In the embodiment, wind power generators (first wind power generator 2a, second wind power generator 2b) were used in addition to solar cells (first solar cell 1a, second solar cell 1b). However, it is also possible to use a water current generator that converts river water flow into electrical energy, a temperature difference generator that uses the temperature difference between a structure and its surroundings, and a vibration generator that uses the vibration of a structure.
(2) In the embodiment described above, the constant voltage circuits 4a, 4b, 4c, and 4d with overcurrent limiting functions were used, but the power generated by the solar cells and wind power generators is small, and the charging current is limited to the secondary batteries 12, 22. If the charging current is below the charging current limit value, there is no need to have a function to limit overcurrent.
(3) In the embodiment described above, the maximum power point tracking control units 3b and 3d were connected to the wind power generators (first wind power generator 2a, second wind power generator 2b), but the maximum power point tracking control unit There is no need to connect 3b and 3d.
(4) The natural energy wireless communication device 100 of the above embodiment sends data from a sensor (for example, an imaging camera) that consumes a large amount of power to a server or a short-distance wireless base unit in short cycles, for example, when monitoring infrastructure structures. It can be applied to such systems.

1a 1st solar cell (natural energy power generation equipment)
1b Second solar cell (natural energy power generation equipment)
2a 1st wind power generator (natural energy power generation equipment, other power generation equipment)
2b Second wind power generator (natural energy power generation equipment, other power generation equipment)
3a, 3b, 3c, 3d Maximum power point tracking control section 4a, 4b, 4c, 4d Constant voltage circuit with overcurrent limiting function (overcurrent limiting circuit, low voltage circuit)
5 Rectifying and smoothing circuit 10 First power generation unit 12, 22 Secondary battery 20 Second power generation unit 50 Natural energy storage device 60 Wireless sensor device (load)
100 Natural energy wireless communication device

Claims (7)

A natural energy storage device comprising a plurality of DC power sources that combine a natural energy power generation device and a secondary battery that charges the power generated by the natural energy power generation device,
A natural energy storage device characterized in that the secondary battery of the DC power source that generates a large amount of power is connected to a load, and the secondary battery of the DC power source that generates a small amount of power is disconnected from the load. Device. The natural energy storage device according to claim 1,
The natural energy power generation device is a combination of a solar cell and a wind power generator,
A natural energy power storage device characterized in that the secondary battery is charged by the solar cell or the wind power generator, whichever generates more power. The natural energy storage device according to claim 1 or 2,
A natural energy storage device characterized in that a current obtained by dividing the output power at the maximum power point of the natural energy power generation device by the voltage of the secondary battery is less than an allowable charging current of the secondary battery. A natural energy power storage device that combines a natural energy power generation device and a secondary battery that charges the power generated by the natural energy power generation device,
The natural energy power generation device is a combination of a solar cell and a wind power generator,
A natural energy power storage device characterized in that the secondary battery is charged by the solar cell or the wind power generator, whichever generates more power. A natural energy wireless communication device comprising the natural energy storage device according to claim 1 or 2 and a wireless sensor device that wirelessly transmits information from various sensors to the outside,
A natural energy wireless communication device characterized in that the wireless sensor device functions as the load. A power generation method for a natural energy power storage device comprising a plurality of DC power sources that combine a natural energy power generation device and a secondary battery for charging the power generated by the natural energy power generation device, the method comprising:
A power generation method characterized in that the secondary battery of the DC power source that generates a large amount of power is connected to a load, and the secondary battery of the DC power source that generates a small amount of power is disconnected from the load. A power generation method using a natural energy power storage device that combines a natural energy power generation device and a secondary battery that charges the power generated by the natural energy power generation device,
The natural energy power generation device is a combination of a solar cell and a wind power generator,
A power generation method characterized in that the secondary battery is charged by the solar cell or the wind power generator, whichever generates more power.

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