JP4373409B2 - Power system - Google Patents

Description

  The present invention relates to a power supply system used for a self-driving telemetry data observation apparatus installed in a place where there is no commercial power supply facility such as a mountainous area.

  In Japan, there are many torrent rivers and landslide hazard areas, and large-scale weather disasters are likely to occur due to large and small earthquakes and typhoons. Therefore, in order to understand the scale of damage to infrastructure facilities such as roads and buildings due to such a large-scale weather disaster, and to enable residents to promptly evacuate in the event of a disaster, remote monitoring of various disaster prevention information (telemetry) Is called monitoring or telemonitoring). In general, telemetry installs a telemetry data observation device at an arbitrarily selected observation target location, acquires observation data from various sensors in this telemetry data observation device, and transfers this observation data to a monitoring center via a communication network. It is realized by.

  By the way, the power supply means of the telemetry data observation apparatus can use commercial power equipment in plains and mountainous areas, but cannot use commercial power equipment in non-residential areas such as mountainous areas. For this reason, in non-residential areas, electric power is generated based on natural energy such as sunlight and wind power, and the generated electric power is used as an operation power source. However, since the amount of power generated by natural energy is inherently unstable, sufficient power cannot always be supplied. For example, solar power cannot be generated at night, and the amount of power generation varies greatly depending on the time of cloudy weather or sunshine conditions even during the daytime. Wind power generation is not performed sufficiently in areas where wind is weak, and even in areas where wind is strong, power generation is not performed during times when wind does not blow. Therefore, some measures are required when a device that generates electric power based on natural energy is used as a power source.

  Therefore, conventionally, a power supply system in which a device that converts natural energy into electric power and a battery are used is used. For example, in a landslide disaster remote monitoring system that transmits measurement data of a rain gauge, water level gauge, inclinometer and extensometer that detects earth and sand movement to a monitoring center server via a communication line, solar power having a power generation capacity of 2.8 W A power supply system in which a power generation unit and a lead storage battery having a capacity of DC12V-7.2Ah are combined is used (see, for example, Non-Patent Document 1).

"Sediment disaster remote monitoring system" (product name "i-SENSOR WEB monitoring system") http://www.i-sensor.com/

However, this type of conventional power supply system has the following problems to be improved.
(1) In the case of photovoltaic power generation, the amount of power generation varies over time due to the passage of clouds, temporary shading by trees and buildings that stand in the vicinity, and daily changes in solar altitude. However, secondary batteries that store electricity using chemical changes, such as lead-acid batteries, have a slow storage speed. Cannot follow. As a result, the electromotive force supplied from the solar battery cannot be efficiently stored, and much time is required to charge the storage battery. In addition, even if a change occurs in an event to be observed before the storage battery is fully charged and electric power is required, it is not possible to cope with this and a problem such as loss of important observation data occurs.

  (2) Secondary batteries that store electricity using chemical changes, such as lead-acid batteries, have a slow discharge rate because the discharge rate is controlled by a chemical reaction, and may not be able to follow the power supply associated with high-speed load fluctuations. is there. For example, in the telemetry data observation apparatus, when an abrupt event change occurs, the observation data is frequently acquired and the observation data is frequently transferred. In such a case, the telemetry data observation apparatus requires a rapid power supply, but sufficient power cannot be rapidly supplied in response to this request, resulting in the loss of important observation data and transmission loss. May occur. In addition, there is a concern that charging by natural energy cannot follow the rapid discharge, and the remaining amount of power storage does not satisfy the desired power. In order to solve this problem, it is necessary to increase the capacity of the storage battery and increase the output power of the solar battery, etc., but this not only increases the size and price of the power supply system, The problem arises that redundant storage capacity increases.

The present invention has been made paying attention to the above circumstances, and a first object thereof is a power supply that can be efficiently charged based on a high-speed electromotive force that changes with time due to natural energy, and that can be charged at low cost and with a large capacity. Is to provide a system.
A second object is to provide a power supply system capable of rapid discharge in response to high-speed load fluctuations and inexpensive and capable of long-time discharge.

In order to achieve the first object, the first aspect of the present invention provides the following means. That is, a power generation unit that generates power based on natural energy, a power storage unit that stores power generated by the power generation unit, and a charge / discharge control unit that controls storage of power in the power storage unit, The power storage unit includes a high-speed charge / discharge power storage unit having a first power storage speed faster than a power generation speed of the power generation unit, and a second power slower than the first power storage speed. And a low-speed charge / discharge power storage unit having a power storage speed of. And the electric power produced | generated by the said electric power generation part is first supplied to the said high-speed charging / discharging electrical storage part by the said charging / discharging control unit, and the said high-speed charging / discharging electrical storage part is charged. On the other hand, after the start of charging of the high-speed charge / discharge power storage unit, when charging is performed at the charge rate of the high-speed charge / discharge power storage unit, when the power storage amount reaches a value smaller than the saturation value, Discharges the electric power stored in the high-speed charge / discharge power storage unit while supplying the power generated by the power generation unit to the high-speed charge / discharge power storage unit and continuing to charge the high-speed charge / discharge power storage unit. The low-speed charge / discharge power storage unit is supplied to charge the low-speed power storage unit.

  Therefore, when charging the power storage unit, first, the high-speed charge / discharge power storage unit is charged, and when the amount of power stored in the high-speed charge / discharge power storage unit reaches a predetermined value, the high-speed power storage unit is subsequently charged. While continuing, an operation for transferring the power of the high-speed power storage unit to the low-speed power storage unit is performed. For this reason, even when the electric power generated by the electric power generation unit changes at high speed due to the influence of temporal fluctuation of natural energy, it is possible to efficiently store this electric power in the high-speed charge / discharge electric storage unit. In addition, when a certain amount of power is stored in the high-speed charge / discharge power storage unit, power is transferred from the high-speed charge / discharge power storage unit to the low-speed charge / discharge power storage unit. It becomes possible to accumulate. Furthermore, combining a high-speed and expensive high-speed charge / discharge power storage unit with a low-speed but low-speed low-speed charge / discharge power storage unit makes the system less expensive than a case where only the high-speed charge / discharge power storage unit accumulates the total power storage amount. You can also.

In order to achieve the above first and second objects, a second aspect of the present invention is that the high-speed charge / discharge power storage unit of the power storage unit has a first discharge rate faster than the power consumption rate of the load. And the low-speed charge / discharge power storage unit has a second discharge rate that is slower than the first discharge rate. The charge / discharge control unit first discharges the electric power stored in the high-speed charge / discharge power storage unit and supplies it to the load. Then, after the start of discharging of the high-speed charge / discharge power storage unit, when discharging is performed at the discharge rate of the high-speed charge / discharge power storage unit, when the remaining power storage time decreases to a value larger than the lower limit value, While discharging from the high-speed charge / discharge power storage unit to the load, the power stored in the low-speed charge / discharge power storage unit is discharged and supplied to the high-speed charge / discharge power storage unit. It is designed to be charged.

  Therefore, when power is supplied from the power storage unit to the load, power is first supplied from the high-speed charge / discharge power storage unit to the load. An operation of transferring the power of the low-speed power storage unit to the high-speed power storage unit while the power supply from the storage unit to the load is continued is performed. For this reason, even when the time fluctuation of the load is fast and rapid discharge is required, it is possible to reliably supply power to the load. In addition, when the remaining charge of the high-speed charge / discharge power storage unit falls below a predetermined value, power is transferred from the low-speed charge / discharge power storage unit to the high-speed charge / discharge power storage unit, so that power is supplied to the load for a long time. It becomes possible. Furthermore, combining a high-speed and expensive high-speed charge / discharge power storage unit with a low-speed but low-speed low-speed charge / discharge power storage unit makes the system less expensive than a case where only the high-speed charge / discharge power storage unit accumulates the total power storage amount. You can also.

In short, according to the present invention, it is possible to provide a power supply system that can be charged efficiently based on a high-speed electromotive force that varies with time due to natural energy, and that can store electricity at a low cost and a large capacity.
In addition, it is possible to provide a power supply system that is capable of rapid discharge corresponding to high-speed load fluctuations and that is inexpensive and capable of long-term discharge.

Embodiments according to the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a telemetry system including a self-supporting drive type telemetry data observation apparatus according to an embodiment of the present invention. In this telemetry system, a telemetry data observation device 1 is installed at an observation point such as a mountainous area, and a data collection device 2 is installed at a government office of a national or local government. The telemetry data observation device 1 and the data collection device 2 Are connected via a communication network 3.

  The telemetry data observation apparatus 1 is a self-supporting drive type, and includes a charge / discharge control unit 11, an energy conversion unit 12, a power storage unit 13, and a data logger 14. The energy conversion part 12 consists of a solar cell panel, for example, and converts sunlight energy into electric power. In addition, as the energy conversion part 12, it is also possible to use another converter using natural energy such as a wind power generator.

  The power storage unit 13 is for storing the power generated by the energy conversion unit 12, and includes a high-speed charge / discharge power storage unit 131 and a low-speed charge / discharge power storage unit 132. The high-speed charge / discharge power storage unit 131 has a first charge / discharge time constant and further includes a first power storage capacity, and is configured of an electric double layer capacitor, for example, as shown in FIG. The first charge / discharge time constant is such that the charge time constant can follow the time variation of the power generated by the energy conversion unit 12, and the discharge time constant is a load variation, that is, the power required by the data logger 14. Each is set to a value that can follow the time variation.

  On the other hand, the low-speed charge / discharge power storage unit 132 has a second charge / discharge time constant longer than the first charge / discharge time constant and a second charge capacity larger than the first charge capacity. A secondary battery using a chemical change, for example, a lead storage battery as shown in FIG. The second power storage capacity is set to a power storage amount that can drive the data logger for 24 hours, for example.

  The charge / discharge control unit 11 includes, for example, an information processing unit 111, an information storage unit 112, a serial communication interface 113, and a charge / discharge control circuit 114 as shown in FIG. First of all, the charge / discharge control circuit 114 supplies the power generated by the energy conversion unit 12 to the power storage unit 13 for charging, and discharges the power stored in the power storage unit 13. Each of the operations to be supplied to the data logger 14 which is a load is controlled.

  In the charging control, first, the high-speed charge / discharge power storage unit 131 is charged, and when the charge time reaches a preset time, the high-speed charge / discharge power storage unit 131 is charged while continuing to charge the high-speed charge / discharge power storage unit 131 thereafter. Control is performed to transfer the stored power to the low-speed charge / discharge power storage unit 132. At this time, when the high-speed charge / discharge power storage unit (electric double layer capacitor) 131 is charged, a backflow prevention process for the charged power is performed. Further, when charging the low-speed charge / discharge power storage unit (lead storage battery) 132, constant voltage charging is required, so that the voltage value discharged from the high-speed charge / discharge power storage unit (electric double layer capacitor) 131 is a constant value. To prevent overcharging.

  In the discharge control, first, the electric power stored in the high-speed charge / discharge power storage unit 131 is discharged and supplied to the data logger 14, and when the discharge time has elapsed in advance, the high-speed charge / discharge power storage unit 131 thereafter. Control is performed to discharge the electric power stored in the low-speed charge / discharge power storage unit 132 and transfer it to the high-speed charge / discharge power storage unit 131 while continuing the discharge.

  The information processing unit 111 monitors the charge / discharge state of the power storage unit 13 by the charge / discharge control circuit 114 and stores the detection information in the information storage unit 112 when an abnormal state is detected. At the same time, the detection information is read from the information storage unit 112 and output from the serial communication interface 113 to the data logger 14 as a status notification signal.

  The data logger 14 includes a sensor 15, an information processing unit 16, and a communication interface 17, and further includes a power supply unit 141, a serial communication interface 142, and an information storage unit 143 as shown in FIG. Among these, the power supply unit 141 supplies the power supplied from the charge / discharge control circuit 114 to each circuit unit in the data logger 14. The serial communication interface 142 is used to exchange charge / discharge control signals and status notification signals with the charge / discharge control unit 11.

  As illustrated in FIG. 2, the sensor 15 includes a rainfall sensor, and for example, a commercially available falling mass type rain gauge is used. In this falling mass type rain gauge, a constant voltage is applied (pulled up) to the signal line from the data logger 14, and when rain accumulates in a certain capacity of the mass, it falls and contacts the contacts, thereby In this structure, the amount of rain per unit time is measured by counting the contact pulses generated at the data logger 14. 2 exemplifies the case where the rain sensor 153 is accommodated in the data logger 14 and is operated using a part of the electric power supplied from the charge / discharge control circuit 114 to the data logger 14. When the built-in rain sensor is used, the rain sensor can be installed outside the telemetry data observation apparatus 1.

The information processing unit 16 is composed of, for example, a microcomputer, and comprehensively controls the rainfall observation operation in the data logger 14 and the data transmission / reception operation with the data collection device 2 in accordance with an application program stored in a program memory (not shown).
The information storage unit 143 is provided with an area for storing observation data detected by the rainfall sensor 15 and an area for storing an observation / transfer control table used for controlling the information processing unit 16. The communication interface 17 is for transferring data to and from the data collection device 2 via the communication network 3, and includes a wireless packet communication interface, for example, as shown in FIG.

The data collection device 2 includes a communication interface 22 and a data processing unit 23. Specifically, the communication interface 22 and the data processing unit 23 are configured by a general-purpose computer 21.
The communication network 3 includes an IP (Internet Protocol) network represented by the Internet, for example, and a plurality of access networks for accessing the IP network. As the access network, for example, a DSL (Digital Subscriber Line) or a wired subscriber network using an optical transmission line, a LAN, a wireless LAN (Local Area Network), a mobile communication network, or a dedicated line network is used.

Next, the operation of the apparatus configured as described above will be described using the charge sequence and the discharge sequence shown in FIGS.
(1) Charging operation of the power storage unit 13
The electric double layer capacitor 131 has a charging characteristic of W (t) as shown in FIG. In other words, it has the ability to charge at a storage amount (storage speed) of a1 per unit time. On the other hand, the lead storage battery 132 has a charging characteristic of X2 (t) as shown in FIG. In other words, it has the ability to charge at a storage amount (storage speed) of a2 per unit time. Further, although the solar energy generally varies from moment to moment, it can be regarded that it increases in proportion to the time t if viewed in a sufficiently short time. Here, let α be the amount of solar irradiation energy per unit time. Thus, the charging speed of the electric double layer capacitor 131 is faster than the changing speed of solar energy, while the charging speed of the lead storage battery 132 is slower than the changing speed of solar energy. This relationship is expressed by an expression:
a1 <α <a2
It becomes.

  Now, when the irradiation of sunlight is started at time t = 0 as shown in FIG. 3 while the power storage unit 13 is not charged, the charged amount of the electric double layer capacitor 131 is less than the threshold value. First, the discharge control circuit 114 starts charging the electric double layer capacitor 131. At this time, the accumulative speed of the electric double layer capacitor 131 is higher than the change rate of solar energy as shown in the above equation. Therefore, the electric double layer capacitor 131 can store all the solar energy, and as a result, as shown by O-B0 in FIG.

  Then, when time elapses from the charging start time t = 0 and reaches time t0, the charge / discharge control circuit 114 continues to charge the electric double layer capacitor 131 and supplies the electric power stored in the electric double layer capacitor 131. Control to transfer to the lead battery 132 is performed. Therefore, after that, charging of the lead battery 132 is started, and in the lead battery 132, the storage amount X2 (t) increases according to the storage speed a2 of the lead battery 132 as indicated by A0-B1-B2 in FIG. At this time, the electric double layer capacitor 131 is discharged to the lead battery 131 while continuing to be charged with solar energy, and thus apparently charged at a rate of α-a2 as indicated by B0-C1-C2 in FIG. As a result, the storage amount X1 (t) increases. At time t2, charging of the electric double layer capacitor 131 ends.

  The time t0 is set to a time when the charged amount will reach E0, which is a value smaller than the saturation value Em, when charging is performed at the charging speed of the electric double layer capacitor 131. Further, t2 is set to a time when the amount of electricity stored in the electric double layer capacitor 131 will reach the saturation value Em. Instead of monitoring t0 and t2, the amount of electricity stored in the electric double layer capacitor 131 is monitored. When the values correspond to B0 and C0 (= Em), respectively, switching of the charge control mode and charge termination processing are performed. May be performed.

(2) Discharge operation of power storage unit
The electric double layer capacitor 131 has a discharge characteristic of V (t) as shown in FIG. That is, it has the ability to discharge the stored power at a discharge amount (discharge rate) of −b1 per unit time. On the other hand, the lead storage battery 132 has a discharge characteristic of Y2 (t) as shown in FIG. That is, it has the ability to discharge the amount of electricity stored at a discharge amount (discharge rate) of -b2 per unit time. Further, assuming that the power consumption by the data logger 14 is constant, the power consumption per unit time is expressed as β as shown in FIG. Thus, the discharge rate of the electric double layer capacitor 131 is faster than the power consumption rate of the data logger 14, while the charge rate of the lead storage battery 132 is slower than the power consumption rate of the data logger 14. This relationship is expressed by an expression:
b1>β> b2
It becomes.

Now, it is assumed that both the electric double layer capacitor 131 and the lead storage battery 132 are fully charged. In this state, it is assumed that the data logger 14 starts the rain observation operation and the observation data transfer operation. Then, the charge / discharge control circuit 114 first starts discharging the stored amount from the electric double layer capacitor 131. At this time, the discharge amount per unit time (slope −b1) of the electric double layer capacitor 131 is larger than the power consumption per unit time (slope β) of the data logger 14. Therefore, the electric double layer capacitor 131 can supply all the required power to the data logger 14. As a result, as shown by O-B0 in FIG. 4, discharge is performed at a speed indicated by the slope β.

Then, at time t0, the charge / discharge control circuit 114 thereafter starts the transfer of power from the lead storage battery 132 to the electric double layer capacitor 131 while continuing the discharge from the electric double layer capacitor 131. Therefore, thereafter, discharge from the lead battery 132 is started, and in the lead battery 132, the storage amount Y2 (t) decreases according to the discharge rate b2 of the lead battery 132 as indicated by A0-B1-B2 in FIG. Further, at this time, the electric double layer capacitor 131 discharges the charged amount to the data logger 14 while being charged from the lead battery 132. Therefore, as shown by B0-C1-C2 in FIG. The amount of stored electricity Y1 (t) gradually decreases. At time t2, the discharge from the electric double layer capacitor 131 ends.

  The time t0 is set to a time when the remaining amount of electricity stored will decrease to E1, which is a certain amount larger than the lower limit value Ep, when discharging is performed at the discharge rate of the electric double layer capacitor 131. . Also, t2 is set to a time when the remaining amount of electricity stored in the electric double layer capacitor 131 will decrease to the lower limit value Ep. Instead of monitoring t0 and t2, the remaining amount of electricity stored in the electric double layer capacitor 131 is monitored. When the values correspond to B0 and C0 (= Ep), the discharge control mode is switched and the discharge is completed. Processing may be performed.

  As described above, in this embodiment, the power storage unit 13 is configured by combining the electric double layer capacitor 131 and the lead storage battery 132. When the power storage unit 13 is charged, the electric double layer capacitor 131 is charged first, and the electric double layer capacitor 131 is led from the electric double layer capacitor 131 while continuing to charge the electric double layer capacitor 131 at a time t0. Electric power is transferred to the storage battery 132. For this reason, it is possible to efficiently store the electromotive force having a large time fluctuation of the solar cell panel 12, and it is possible to provide an inexpensive and large capacity power supply system.

In addition, when discharging the electric power stored in the power storage unit 13 and supplying it to the data logger 14, first, discharging of the charged amount from the electric double layer capacitor 131 is started. While continuing the discharge from the capacitor 131, the power is transferred from the lead storage battery 132 to the electric double layer capacitor 131. Therefore, it is possible to supply sufficient power to the data logger 14 that consumes a large amount of power per unit time, and it is possible to provide a power supply system that can supply power for a long time at a low cost.

  The present invention is not limited to the above embodiment. For example, three or more power storage units with different charge / discharge time constants are prepared, and the power storage units are charged in order from the one with the smallest charge time constant and discharged in the order from the one with the smallest discharge time constant. May be. Also, when there are multiple loads with different power consumption per unit time, or when the power consumption per unit time of one load fluctuates with time, it corresponds to the power consumption required by the load The power storage unit having a discharge time constant to be selected may be adaptively selected to control the power to be discharged.

In the above embodiment, the case where solar power generation is used has been described as an example. However, when other natural energy such as wind power generation or geothermal power generation is used to generate power, the power is stored in the power storage unit and used. This invention can also be applied.
In addition, the type of sensor, the configuration of the data logger and the charge / discharge control unit, the configuration of the power storage unit, the type of the high-speed charge / discharge power storage unit and the low-speed charge / discharge power storage unit, the control procedure control contents by the data logger, etc. Various modifications can be made without departing from the scope of the invention.

  In short, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

It is a block diagram which shows the structure of the telemetry system containing the self-supporting drive type telemetry data observation apparatus concerning one Embodiment of this invention. It is a block diagram which shows the specific structure of the self-supporting drive type telemetry data observation apparatus shown in FIG. It is a figure which shows the charge sequence of the electric power storage unit by the charging / discharging control unit of the self-supporting drive type telemetry data observation apparatus shown in FIG. It is a figure which shows the discharge sequence of the electric power storage unit by the charging / discharging control unit of the self-supporting type telemetry data observation apparatus shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,10 ... Self-supporting-type telemetry data observation device, 2 ... Data collection device, 3 ... Communication network, 11 ... Charge / discharge control unit, 111 ... Information processing part of charge / discharge control unit, 112 ... Information storage of charge / discharge control unit 113, serial communication interface, 114, charge / discharge control circuit, 12 ... energy conversion unit (solar cell panel), 13 ... power storage unit, 131 ... high-speed charge / discharge power storage unit (electric double layer capacitor), 132 ... low-speed charge Discharge power storage unit (lead storage battery), 14 ... data logger, 141 ... power supply unit, 142 ... data logger serial communication interface, 143 ... data logger information storage unit, 15 ... rain sensor, 16 ... data logger information processing unit , 17 ... Communication interface (wireless packet communication interface).

Claims (4)

A power generation unit that generates power based on natural energy;
A power storage unit for storing the power generated by the power generation unit;
A charge / discharge control unit for controlling the storage of power in the power storage unit;
The power storage unit is
A high-speed charge / discharge power storage unit having a first power storage speed faster than a power generation speed of the power generation unit;
A low-speed charge / discharge power storage unit having a second power storage speed slower than the first power storage speed,
The charge / discharge control unit includes:
Means for supplying power generated by the power generation unit to the high-speed charge / discharge power storage unit to charge the high-speed charge / discharge power storage unit;
After the start of charging of the high-speed charge / discharge power storage unit, when charging is performed at the charge rate of the high-speed charge / discharge power storage unit, when the power storage amount reaches a value smaller than a saturation value , the power is thereafter While supplying the electric power generated by the generator to the high-speed charge / discharge power storage unit and continuing to charge the high-speed charge / discharge power storage unit, the power stored in the high-speed charge / discharge power storage unit is discharged to A power supply system comprising: means for supplying to the discharge power storage unit and charging the low-speed power storage unit. The high-speed charge / discharge power storage unit of the power storage unit has a first discharge rate faster than the power consumption rate of the load,
The low-speed charge / discharge power storage unit of the power storage unit has a second discharge rate that is slower than the first discharge rate,
The charge / discharge control unit includes:
First, means for discharging the power stored in the high-speed charge / discharge power storage unit and supplying it to the load;
After the start of the discharge of the high-speed charge / discharge power storage unit, when discharging is performed at the discharge speed of the high-speed charge / discharge power storage unit, when the remaining power storage time decreases to a value larger than the lower limit value, thereafter, While continuing the discharge from the high-speed charge / discharge power storage unit to the load, the power stored in the low-speed charge / discharge power storage unit is discharged and supplied to the high-speed charge / discharge power storage unit to charge the high-speed charge / discharge power storage unit. The power supply system according to claim 1, further comprising: means.   3. The high-speed charge / discharge power storage unit has a first power storage capacity, and the low-speed charge / discharge power storage unit has a second power storage capacity larger than the first power storage capacity. Power system.   The power supply system according to claim 1, wherein the high-speed charge / discharge power storage unit is configured by an electric double layer capacitor, and the low-speed charge / discharge power storage unit is configured by a secondary battery using a chemical change.

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