Natural energy power storage device, wireless communication device, and natural energy charging method

Abstract

To increase the degree of freedom in design.SOLUTION: A natural energy power storage device 50 includes a plurality of DC power sources 30, 35 that combine natural energy power generators 10, 20 with secondary batteries 12, 22 that are charged with power generated by the natural energy power generators 10, 20, respectively. The natural energy power storage device connects the secondary battery 12 of the DC power source 30 that generates a large amount of power to a load 60, and does not connect the secondary battery 22 of the DC power source 35 that generates a small amount of power to the load 60. The natural energy power generators 10, 20 can be switched between solar cells and wind power generation facilities.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a natural energy storage device that stores natural energy such as solar power or wind power in a secondary battery, a wireless communication device, and a natural energy charging method. [Background technology]

[0002] There is a technology that uses solar cells and secondary batteries to operate sensor devices such as measuring instruments and image sensors, and wirelessly transmits sensor information to remote locations, day or night. This sensor information includes, for example, water level, flow velocity, bridge vibration, captured images, etc. Patent Document 1 also discloses a technology that uses solar cells, wind power generation, etc. to charge secondary batteries. This wind power generation is used as a backup for the solar cells. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-220348 A (Fig. 2, paragraphs 0039 and 0045) Summary of the Invention [Problem to be solved by the invention]

[0004] The technology described in Patent Document 1 uses one type of secondary battery. Each secondary battery has its own minimum charging current value (for example, 0.01 to 0.02 times the rated capacity [Ah] of the secondary battery). Because of this minimum charging current value, when the power generated by the solar cell and wind turbine becomes low, the secondary battery cannot be charged. Therefore, it is conceivable to connect an additional secondary battery with a small rated capacity. Conversely, it is also conceivable to connect an additional secondary battery with a large rated capacity in order to extend the usage time. Whether it is more appropriate to connect a secondary battery to a solar cell or a hydroelectric generator, etc., depends on the case. In such cases, the technology of Patent Document 1, which uses one type of secondary battery, has limited flexibility, resulting in restrictions on the additional connection of secondary batteries.

[0005] The present invention has been made to solve these problems, and aims to provide a natural energy storage device, a wireless communication device, and a natural energy charging method that allow greater design freedom. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the first invention is a natural energy storage device comprising multiple types of natural energy power generation devices, multiple types of secondary batteries that are charged with the power generated by any one or a combination of the natural energy power generation devices, and a charging path through which each natural energy power generation device charges each secondary battery, characterized in that the charging path is specified based on the magnitude of the power generated by each of the natural energy power generation devices and the level of the charging voltage of the secondary batteries.

[0007] The second invention is a natural energy storage device comprising a natural energy power generation device, multiple types of secondary batteries that are charged with the power generated by the natural energy power generation device, and a discharge path through which each secondary battery discharges to a first load, wherein the discharge path is identified based on the level of the charging voltage of each secondary battery. [Effects of the Invention]

[0008] According to the present invention, the degree of freedom in design can be increased. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a configuration diagram of a wireless communication device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a configuration diagram of a first power generation unit. [Figure 3] FIG. 3 is a configuration diagram of a second power generation unit. [Figure 4] 5 is a flowchart illustrating the operation of the wireless communication device according to the first embodiment of the present invention. [Figure 5]4 is a table showing discharge path conditions of the discharge switch used in the first embodiment of the present invention. [Figure 6] 4 is a table showing charging path conditions of a charging switch used in the first embodiment of the present invention. [Figure 7] FIG. 10 is a configuration diagram of a wireless communication device according to a second embodiment of the present invention. [Figure 8] 10 is a table showing discharge path conditions of a discharge switch used in a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that each drawing is merely a schematic illustration to allow a sufficient understanding of the embodiments. In addition, common or similar components in each drawing are designated by the same reference numerals, and redundant explanations thereof will be omitted.

[0011] (First embodiment) FIG. 1 is a diagram showing the configuration of a wireless communication device according to a first embodiment of the present invention. The wireless communication device 200 is a device that performs wireless communication using natural energy such as solar or wind energy. The wireless communication device 200 includes a natural energy storage device 100 and a first load 150 (for example, a wireless sensor device). The natural energy storage device 100 includes multiple types of power generation units (first power generation unit 10, second power generation unit 20), a generated current monitor 30 that measures the generated current of the first power generation unit 10, a generated current monitor 31 that measures the generated current of the second power generation unit 20, a charge switch 40, multiple secondary batteries 50, 51, a primary battery 55, and a discharge switch 60.

[0012] FIG. 2 is a configuration diagram of the first power generating unit 10, and FIG. 3 is a configuration diagram of the second power generating unit 20. As shown in FIG. The first power generating unit 10 (Fig. 2) includes a solar cell 1, a maximum power point tracking control unit 3a, and a constant voltage circuit with an overcurrent limiting function 4a. The second power generating unit 20 (Fig. 3) includes a wind power generator 2, a rectifying and smoothing circuit 5, a maximum power point tracking control unit 3b, and a constant voltage circuit with an overcurrent limiting function 4b.

[0013] The solar cell 1 converts solar energy into DC power with a voltage V1 and an output current I1. The wind power generator 2 converts wind energy into AC power. The wind power generator 2 is a rotating electric machine connected to a propeller, and generates electricity using wind power. Wind power generation is useful at night, in rainy weather, or when the solar cell 1 is installed under a bridge and sunlight is difficult to reach. The wind-receiving area A [m 2 ], wind speed v [m / s], air density ρ [kg / m 3 ], the kinetic energy W [J] due to wind power is W = (1 / 2) mv 2 =(1 / 2)ρAv 3 The rectifying and smoothing circuit 5 includes a diode and an electrolytic capacitor (not shown), and converts the AC power generated by the wind power generator 2 into DC power.

[0014] The maximum power point tracking control unit 3a varies the output voltage of the solar cell 1 to output a current that provides maximum power. The maximum power point tracking control unit 3b varies the output voltage of the rectifying and smoothing circuit 5 to output a current that provides maximum power. The constant voltage circuits 4a and 4b with overcurrent limiting function step up or step down the output voltage of the solar cell 1 or wind power generator 2 controlled by the maximum power point tracking control units 3a and 3b, and charge the secondary batteries 50 and 51 (Figure 1) up to the nominal voltage Vn. The constant voltage circuits 4a and 4b with overcurrent limiting function also limit the output current to a limit current setting value so as not to charge the secondary batteries 50 and 51 (Figure 1) with an overcurrent.

[0015] The generated current monitors 30, 31 detect the output currents of the first power generation unit 10 and the second power generation unit 20. In other words, the generated current monitors 30, 31 monitor the charging currents of the secondary batteries 50, 51.

[0016] The secondary batteries 50 and 51 are different types of secondary batteries, with different rated capacities C [Ah], or one may be a nickel-metal hydride battery and the other a lithium-ion battery. The nickel-metal hydride battery is a series-parallel connection of single cells with a nominal voltage of 1.2 V. It is preferable that the nominal voltage of the secondary batteries 50 and 51 be the same.

[0017] Each of the secondary batteries 50 and 51 has its own minimum charging current value (e.g., 0.01 to 0.02 times the rated capacity C [Ah] of the secondary battery). Therefore, it is preferable to set the rated capacity of one secondary battery (e.g., secondary battery 50) low so that the other secondary battery (e.g., secondary battery 51) can be charged even when the charging current falls below the minimum charging current value specific to the secondary battery. Furthermore, the secondary batteries 50 and 51 are charged with a constant current of K·C [Ah] / 1 [h] = K·C [A] to prevent overcurrent. In other words, when the secondary batteries 50 and 51 have different rated capacities C [Ah], the maximum charging currents of the constant voltage circuits 4a and 4b with overcurrent limiting function (FIG. 2) are controlled to be different. The primary battery 55 is a battery for battery backup.

[0018] The charging switch 40 has multiple (four) terminals 41, 42, 43, and 44. The ON / OFF between the terminals is controlled by the control unit 90, and multiple charging paths are formed. For example, charging path a is when terminals 41 and 42 are turned ON, and the power generated by the first power generation unit 10 charges the secondary battery 50. Charging path b is when terminals 41 and 44 are turned ON, and the power generated by the first power generation unit 10 charges the secondary battery 51. Charging path c is when terminals 43 and 44 are turned ON, and the power generated by the second power generation unit 20 charges the secondary battery 51. Charging path d is when terminals 43 and 42 are turned ON, and the power generated by the second power generation unit 20 charges the secondary battery 50.

[0019] The discharge switch 60 has multiple (four) terminals 61, 62, 63, and 64. The ON / OFF states between the terminals are controlled by the control unit 90 to form multiple discharge paths. For example, discharge path a is formed when terminals 61 and 64 are turned ON, and energy charged in the secondary battery 50 is discharged to the first load 150. Discharge path b is formed when terminals 62 and 64 are turned ON, and energy stored in the primary battery 55 is discharged to the first load 150. Discharge path c is formed when terminals 63 and 64 are turned ON, and energy charged in the secondary battery 51 is discharged to the first load 150.

[0020] The first load 150 is, for example, a wireless sensor device, and transmits data (captured images, water level data, vibration data, etc.) detected by a sensor unit 153 wirelessly to another wireless communication device (not shown) or a server (not shown) using LTE (Long Term Evolution). The first load 150 is also configured with a sensor unit 153, a control unit 152, and a wireless unit 151, and wirelessly transmits information from various sensors to the outside. The sensor unit 153 is configured with any one or a combination of an imaging device, a water level meter, a vibration sensor, etc. (not shown). The imaging device, for example, periodically captures an image of the water level of a river (for example, every minute or every five minutes). The water level meter, for example, periodically observes the water level of the river. The vibration sensor, for example, detects vibrations of a bridge spanning the river. The first load 150 also communicates with a wireless master unit (not shown) that uses sub-GHz band wireless. Furthermore, the wireless unit 151 of the device itself receives data (captured images, water level data, vibration data, etc.) from other wireless communication devices (not shown). In other words, the wireless communication device 200 as a whole functions as a zero energy gateway. The control unit 152 is a CPU (Central Processing Unit) that controls the sensor unit 153 and the wireless unit 151.

[0021] 4 is a flowchart for explaining the operation of the wireless communication device 200 according to the first embodiment of the present invention. This flow is started by powering on or resetting. The control unit 90 sets the thresholds of the generated current monitors 30 and 31 (S1). After the process of S1, the control unit 90 sets the threshold voltages of the secondary batteries 50 and 51 (S2). The threshold voltages of the secondary batteries 50 and 51 vary depending on the ambient temperature and the power consumption of the first load 150. For example, the threshold voltage is lowered when the ambient temperature is low and raised when the ambient temperature is high. After the process of S2, the control unit 90 measures the charging voltages of the secondary batteries 50 and 51 (S3). After the process of S3, the control unit 90 sets a discharge route based on the discharge route conditions (S4). That is, the control unit 90 sets the discharge switch 60 based on the table of FIG. 5. At this time, if the rated capacities C [Ah] of the secondary batteries 50 and 51 are different, the control unit 90 appropriately sets the maximum charging current of the constant voltage circuits with overcurrent limiting function 4a and 4b (FIG. 2).

[0022] FIG. 5 is a table showing discharge path conditions of the discharge switch 60 used in the first embodiment of the present invention. When the voltage of the secondary battery 50 is higher than the threshold, the discharge path a is selected (conditions A1, A2, A5, A7). When the voltage of the secondary battery 51 is higher than the threshold, the discharge path c is selected in principle (conditions A3, A6), but when the voltage of the secondary battery 50 is also higher than the threshold, the discharge path a is selected (conditions A1, A7). The threshold for the voltage of the secondary battery 51 varies depending on the ambient temperature and the power consumption of the first load 150. For example, when the ambient temperature is low, the threshold is lowered, and when the ambient temperature is high, the threshold is raised.

[0023] Condition A4 occurs when the charging voltages of secondary battery 50 and secondary battery 51 are lower than the threshold and the voltage of primary battery 55 is high, and discharge path b is selected. Condition A8 occurs when the voltages of secondary battery 50, secondary battery 51, and primary battery 55 are lower than the threshold, and none of the discharge paths is used. In other words, under condition A8, only charging of secondary battery 50 and secondary battery 51 is performed.

[0024] Returning to the explanation of the flowchart in Fig. 4, after the process of S4, the control unit 90 measures the current of the generated current monitors 30, 31 (S5). After the process of S5, the control unit 90 sets a charging route based on the charging route conditions (S6) and repeats the voltage measurement (S3). That is, in S6, the control unit 90 sets the charging switch 40 based on the table in Fig. 6.

[0025] The timing for repeating the processes of S3 to S6 can be set arbitrarily. The processes of S3 to S6 may be repeated at predetermined time intervals (at predetermined time intervals), for example. The processes of S3 to S6 may also be repeated when the charging voltage of the secondary batteries 50, 51 changes (or when it is easy to change it) or when the power generated by the first power generating unit 10 and the second power generating unit 20 changes (or when it is easy to change it). The control unit 90 may also execute the process of setting the discharge route (S3 to S4) and the process of setting the charge route (S5 to S6) at different times. For example, it is also possible to set the discharge route before operating the sensor unit 153 and the wireless unit 151, and set the power receiving route after operating the sensor unit 153 and the wireless unit 151.

[0026] FIG. 6 is a table showing the charging path conditions of the charging switch 40 used in the first embodiment of the present invention. When the generated current (charging current) flowing from the first power generation unit 10 is greater than a threshold and the charging voltage of the secondary battery 50 is low, charging path a is selected (conditions B2, B3, B6). That is, when the generated power of the first power generation unit 10 is large and the charging voltage of the secondary battery 50 is low, the secondary battery 50 is charged from the first power generation unit 10. However, when the generated current flowing from the second power generation unit 20 is less than a threshold and the charging voltage of the secondary battery 50 is high, neither secondary battery 50, 51 is charged (B5). When the generated current flowing from the second power generation unit 20 is greater than a threshold and the charging voltage of the secondary battery 51 is low, charging path c is selected (conditions B1, B2, B8). That is, the secondary battery 51 is charged from the second power generation unit 20.

[0027] When the generated current flowing from the first power generation unit 10 is greater than the threshold, the generated current flowing from the second power generation unit 20 is lower than the threshold, and the charging voltage of the secondary battery 51 is low, the charging path b is selected (condition B4). That is, the secondary battery 51 is charged from the first power generation unit 10. When the generated current flowing from the first power generation unit 10 is less than the threshold, the generated current flowing from the second power generation unit 20 is greater than the threshold, and the charging voltage of the secondary battery 51 is low, charging path d is selected (condition B9). That is, the secondary battery 50 is charged from the second power generation unit 20.

[0028] When the generated current flowing from the first power generation unit 10 and the second power generation unit 20 is small, either the secondary battery 50 or the secondary battery 51, whichever has the lower voltage, is charged (B10 to B13). When the generated current flowing from the first power generation unit 10 and the second power generation unit 20 is large, both currents are used to charge either the secondary battery 50 or the secondary battery 51, whichever has the lower voltage (B14, B15). In other words, when the generated current flowing from the first power generation unit 10 and the second power generation unit 20 is large, either the secondary battery 50 or the secondary battery 51 is charged at high speed.

[0029] As described above, according to the natural energy storage device 100 of this embodiment, the power generated by one of the multiple types of power generation units is charged into one of the two types of secondary batteries 50, 51 depending on the magnitude of the power generated by the two types of power generation units (e.g., the first power generation unit 10 and the second power generation unit 20) and the level of the charging voltage of the two types of secondary batteries 50, 51. The charging switch 40 is controlled by the control unit 90, and specifies charging routes a, b, c, and d. Specifying charging routes a, b, c, and d in the matrix table (FIG. 6) makes it easy to change the discharging route.

[0030] As a result, for example, when a power generation unit (e.g., the first power generation unit 10, the second power generation unit 20) is charging a secondary battery with a larger capacity (e.g., secondary battery 50), if the charging current falls below the minimum charging current value specific to the secondary battery, charging is performed by switching to the secondary battery with a smaller capacity (e.g., secondary battery 51).

[0031] According to the discharge switch 60 of this embodiment, any one of the DC power charged in the secondary battery 50, the DC power charged in the secondary battery 51, and the DC power stored in the primary battery 55 is discharged to the first load 150.

[0032] (Second embodiment) The load of the natural energy storage device 100 in the first embodiment is the first load 150 (for example, a wireless sensor device), but an LED lighting device may also be provided.

[0033] FIG. 7 is a diagram showing the configuration of a wireless communication device according to the second embodiment of the present invention. The wireless communication device 201 is configured to include a natural energy storage device 101, a first load 150 (for example, a wireless sensor device), and a second load 160 (for example, an LED lighting device).

[0034] Similar to the above embodiment, the natural energy storage device 101 includes a plurality of types of power generation units (first power generation unit 10, second power generation unit 20), a power generation current monitor 30 that measures the power generation current of the first power generation unit 10, a power generation current monitor 31 that measures the power generation current of the second power generation unit 20, a charge switch 40, a plurality of secondary batteries 50, 51, and a primary battery 55. However, the natural energy storage device 101 differs in that it includes a discharge switch 69 instead of the discharge switch 60 of the above embodiment.

[0035] The discharge switch 69 further includes a terminal 65 in addition to the discharge switch 60 (FIG. 1) of the above embodiment. When the terminals 63 and 65 are set to the ON state, a discharge path d is formed. The discharge path d discharges the DC power charged in the secondary battery 51 to the second load 160. When the discharge path c is not used, the discharge path d becomes a path connecting the second load 160 to a secondary battery 51 different from the secondary battery 50 connected to the first load 150. The second load 160 is, for example, an LED lighting device that illuminates the surroundings in synchronization with an imaging device (not shown) included in the sensor unit 153.

[0036] FIG. 8 is a table showing discharge path conditions of the discharge switch 69 used in the second embodiment of the present invention. Discharge paths a and b are the same as those in FIG. 5 (conditions A1 to A8) of the above embodiment. Discharge path c is not used in principle, but may be used if discharge paths a and b are not used. Discharge path d is selected when the voltage of the secondary battery 51 is higher than the threshold, that is, under conditions C1, C3, C6, and C7. Note that under condition C6, discharge paths a and b are not used, and only discharge path d is used. Condition C6 is intended, for example, to light up only the LED lighting device when another device (for example, an imaging device without an LED lighting device) is operating nearby.

[0037] As described above, the natural energy wireless communication device 201 of this embodiment can connect the second load 160 to which DC power is supplied by a secondary battery different from the secondary battery connected to the first load 150. For example, when the secondary battery 50 and the first load 150 are connected, the second load 160 is connected to the secondary battery 51.

[0038] (Variation) The present invention is not limited to the above-described embodiment, and various modifications are possible, for example, as follows. (1) In the above embodiments, the charge switch 40 and the discharge switch 60 are controlled using a matrix table (FIGS. 5, 6, and 8). However, it is not always necessary to use a matrix table.

[0039] (2) In each embodiment, in addition to solar cells, wind power generators are used. However, it is also possible to use water flow generators that convert the water flow of rivers into electrical energy, temperature difference generators that utilize the temperature difference between a structure and its surroundings, vibration generators that utilize the vibration of a structure, indoor photovoltaic power generation, etc. (3) In each embodiment, two types of natural energy power generation equipment (solar cell 1, wind power generator 2) charged two types of secondary batteries 50, 51, but three or more types of natural energy power generation equipment (e.g., solar cell, water current generator, temperature difference generator) may charge two or three types of secondary batteries.

[0040] (4) In each embodiment, the maximum power point tracking control unit 3b is connected to the wind power generator 2 (FIG. 3), but it is not necessarily required to connect the maximum power point tracking control unit 3b. (5) The natural energy wireless communication devices 200, 201 of each embodiment can be applied to a system in which data from a sensor (e.g., an imaging device) that consumes a large amount of power for infrastructure monitoring is sent to a server or a short-range wireless base station at short intervals. [Explanation of symbols]

[0041] 1. Solar cells (natural energy generation equipment) 2. Wind turbines (natural energy power generation equipment, other power generation equipment) 3a, 3b Maximum power point tracking control section 4a, 4b Constant voltage circuit with overcurrent limiting function (overcurrent limiting circuit, low voltage circuit) 5 Rectifier smoothing circuit 10. First Power Generation Unit 20 Second Power Generation Unit 30,31 Power generation current monitor 40 Charging switch 50,51 Secondary battery 55 Primary battery 60,69 Discharge switch 61, 62, 63, 64, 65 terminals 100,101 Natural energy storage device 150 First load (wireless sensor device) 151 Radio Department 152 Control Unit 153 Sensor unit 160 2nd load (LED) 200, 201 Wireless communication device C Rated capacity a,b,c,d Charging path, discharging path

Claims

1. A natural energy storage device including a plurality of types of natural energy power generation devices, a plurality of types of secondary batteries that are charged with power generated by any one or a combination of the natural energy power generation devices, and a charging path through which each of the natural energy power generation devices charges each of the secondary batteries, The charging path is specified based on the magnitude of the power generated by each of the natural energy power generation devices and the level of the charging voltage of the secondary battery. A natural energy storage device characterized by:

2. The natural energy storage device according to claim 1, a discharge path through which any one of the plurality of types of secondary batteries discharges to a first load; The discharge path is specified based on the level of the charging voltage of the secondary battery. A natural energy storage device characterized by:

3. The natural energy storage device according to claim 2, Further comprising a primary battery; The discharge path is identified based on the level of the charging voltage of each of the secondary batteries and the voltage of the primary battery. A natural energy storage device characterized by:

4. The natural energy storage device according to claim 1, The charging path is configured by a charging switch that connects any one of the natural energy power generation devices to any one of the secondary batteries. A natural energy storage device characterized by:

5. The natural energy storage device according to claim 4, The charging switch is controlled based on a matrix table in which combinations of the magnitude of the power generated by each of the natural energy power generation devices correspond to ON / OFF states. A natural energy storage device characterized by:

6. The natural energy storage device according to claim 1, The plurality of natural energy power generation devices are solar cells and wind power generators. A natural energy storage device characterized by:

7. A natural energy storage device including a natural energy power generation device, a plurality of types of secondary batteries for charging with power generated by the natural energy power generation device, and a discharge path for discharging each of the secondary batteries to a first load, The discharge path is identified based on the level of the charging voltage of each of the secondary batteries. A natural energy storage device characterized by:

8. The natural energy storage device according to claim 7, Further comprising a primary battery; The discharge path is identified based on the level of the charging voltage of each of the secondary batteries and the voltage of the primary battery. A natural energy storage device characterized by:

9. The natural energy storage device according to claim 7, The discharge path is specified by a discharge switch that is controlled based on a matrix table that corresponds high and low combinations of the charging voltage of the secondary battery to ON / OFF. A natural energy storage device characterized by:

10. The natural energy storage device according to claim 7, a second load different from the first load is further connected; The discharge path includes a path connecting the second load to a secondary battery different from the secondary battery connected to the first load. A natural energy storage device characterized by:

11. The natural energy storage device according to claim 1 or claim 7, The plurality of types of secondary batteries include secondary batteries with different rated capacities. A natural energy storage device characterized by:

12. A wireless communication device comprising the natural energy storage device according to claim 2 or 7 and a wireless sensor device that wirelessly transmits information from various sensors to an external device, The first load is the wireless sensor device. A wireless communication device comprising:

13. A natural energy charging method for a natural energy storage device including a plurality of types of natural energy power generation devices, a plurality of types of secondary batteries that are charged with power generated by any one or a combination of the natural energy power generation devices, and a charging path through which each of the natural energy power generation devices charges each of the secondary batteries, comprising: The charging path is identified based on the magnitude of the power generated by each of the natural energy power generation devices and the level of the charging voltage of the secondary battery. A natural energy charging method.

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