JP4845866B2 - Power supply for terminal network controller - Google Patents

Description

  The present invention relates to a power supply device for a terminal network control device of a telemeter system that performs remote meter reading using a communication line.

  Conventionally, as shown in FIG. 4, a telemeter system has been constructed in which a meter 4, such as gas, water, electricity, etc., is remotely measured from the center side device 1 using a communication line 2 such as a telephone line. A terminal network control unit (NCU) 33 connected to a meter such as water, gas or electricity is provided on the terminal side, and the terminal network control device 33 can communicate with the center side device via the communication line 2. .

  Since the terminal network controller 33 is mainly installed outdoors, an independent power source such as a battery drive is required without using a commercial power source in terms of workability. The terminal network control device 33 is an ultra-low power consumption type device that consumes as little as several tens of microwatts during standby and can operate for about 10 years with a single lithium battery.

Recently, however, the number of terminal network control units (NCUs) 23 using the wireless communication 6 as shown in FIG. The center side apparatus 1 is connected to the radio base station 5 via the communication line network 2, and the NCU 23 can communicate with the center side apparatus 1 via the radio communication 6 and further via the radio base station 5 and the communication line network 2. It has become. The reason why the number of NCUs 23 is increased is that there is a merit that if it is within the area of the wireless communication 6, it can be installed in a place where there is no communication line, or wiring work such as a telephone line is unnecessary. In the telemeter system, a master unit is connected to the terminal network control device 23, a slave unit is connected to each meter 4, and the master unit and a plurality of slave units are connected by, for example, specific low power wireless communication. Are known. Since the plurality of slave units transmit the monthly meter reading data of the meter 4 to the terminal network control device 23 via the master unit, the terminal network control device 23 sends the meter reading data to the center side via the radio base station 5. By transmitting to the apparatus 1, remote meter reading of the meter 4 can be performed.

  An existing mobile phone network is used for wireless communication. The cellular phone network has a wide communicable area and is most suitable for the NCU 23 that performs meter reading in each household in the country. In order to use the mobile phone network, the mobile phone wireless module 7 is mounted on the NCU 23. The mobile phone wireless module 7 is a module specialized for data communication using a mobile phone network, except for a call unit, a display unit, and an operation unit that are unnecessary for data communication from the mobile phone, Only the data communication unit is modularized.

  However, even though the mobile phone wireless module 7 is also reduced in power consumption, it consumes power of several milliwatts to tens of milliwatts even during standby. This power consumption is 100 times or more of the power consumption compared with the conventional NCU33. The reason for such a large amount of power consumption is that, compared with the conventional NCU 33, which has only a few LSIs such as a microcomputer and a telephone line modem, the mobile phone wireless module 7 is integrated with many LSIs. This is because standby power overlaps and the wireless unit periodically performs operations such as exchange of position information with the base station 5 even during standby when data communication is not being performed.

  In the case of the NCU 23 using the wireless communication 6 as described above, the power consumption is large, and in the case of one or several lithium batteries as in the past, the battery life is too short and the battery needs to be replaced frequently. Can not. If commercial power is used, power supply work is required, so the installation location of the NCU 23 is selected. For this reason, when a commercial power source cannot be used, it operates with the power supply device 24 which mounts many lithium batteries, such as 40 pieces and 80 pieces. However, even when such a large number of lithium batteries are mounted, the battery life of 10 years is not far from that of the conventional NCU33.

  Although the power consumption of the NCU 23 using the mobile phone network is large, the power consumption during standby, which accounts for the majority of the total power consumption, is only about several tens of milliwatts. Although this level of power consumption requires a large number of batteries as described above to cover a period of several years with batteries, it is a small amount of power to use a commercial power source.

  A solar cell is conceivable as a power source that fits this level of power consumption. As described in Patent Document 1, if a solar battery and a storage battery are combined, an independent power source is obtained. However, in this method, there is a risk that the power supply may be interrupted when the bad weather continues and the terminal network control device operates frequently. That is, there is a possibility that the terminal is turned off at the time of meter reading, which hinders meter reading work. Still, meter reading is possible by repeating re-reading, but it is unreliable and cannot be used for applications that use reports from terminals such as low gas level notifications, cylinder replacement notifications, and security emergency notifications.

  The power consumption during operation of the terminal network control device using the cellular phone network is several tens of times larger than that during standby. This means that the total amount of power required by the terminal network control device depends greatly on the operating conditions of the terminal.

  If the power supply device has the ability to supply power to the terminal network control device even if it is used in bad weather and the worst operating conditions, there is a problem that the solar cell panel and the power storage element become too large and are not realistic.

  The terminal network control device is normally required to have a life equivalent to the 10-year life of the gas meter. When a lead storage battery or a lithium ion battery is used as a power storage element, the energy density is large and a large capacity can be obtained with a small volume. However, a 10-year life cannot be expected due to the number of times of charge / discharge and deterioration over time.

Adopting these selected large solar cell panels and power storage elements as power supply devices is based on bad weather and worst operating conditions. Such a condition is a rare state in actual use, and such a power supply device is almost over-specified. In the case of a configuration including only a solar battery and a power storage element, it takes time until the power from the solar battery is charged when the power storage element is not charged at the start of use. Or it needs to be charged separately.
JP 2000-102191 A

  Therefore, in a power supply device for a terminal network control device that should be able to supply power for a long time while having low power consumption during standby, it is efficient by using a large-capacity storage element to be charged and a spare battery in combination. There is a problem to be solved in terms of obtaining power supply specifications.

  An object of the present invention is to provide a power supply device for a terminal network control device that should be able to supply power over a long period of time while having low power consumption during standby. The object is to provide a power supply device for a terminal network control device capable of suppressing the manufacturing cost.

A power supply device for a terminal network control device according to the present invention includes a terminal network control device that is a parent device wirelessly connected to a center side device via a mobile phone line, a plurality of child devices connected to the parent device, A telemeter system comprising a meter connected to a slave unit, wherein the plurality of slave units transmit monthly meter reading data of the meter to the terminal network control device, and through the wireless communication, The terminal network control device is a power supply device for the terminal network control device of a telemeter system that performs remote meter reading of the meter by transmitting the meter reading data to the center side device, the center side device and the terminal network The control device performs wireless communication via the mobile phone line, and the power supply device has a solar cell power source and a large capacity capacity for storing and supplying electric power obtained by the solar cell power source. And a lithium battery for performing power source backup of the terminal network control device when the large-capacity capacitor cannot supply power, and the lithium battery has a power other than the power required for the wireless communication of the terminal network control device. The solar cell power supply and the large-capacity capacitor have a capacity capable of supplying electric power for 10 years, and the power generation capacity and the electric storage capable of storing electric power for executing the remote meter reading for four days when the large-capacity capacitor is fully charged on a fine day It is characterized by having each capacity .

  Although the capacity of the large-capacity capacitor is reduced with the lapse of time, there is not much deterioration due to the number of times of charging / discharging, and if it is used as a power storage element, it can be expected to have a long life of 10 years. Capacitor capacity is set with a margin in bad weather and standard conditions, but capacitors tend to increase in volume due to their low energy density, so spare lithium batteries for power shortages due to reduced size It is supposed to be supplemented with. That is, when the capacitor falls below a certain voltage, such as when the use starts or when the terminal network control device operates above the standard condition, the power supply is switched to the power supply from the spare battery.

  The battery is rarely consumed under the standard condition, but the battery may be consumed when the terminal is severely operated or when a large number of temporary operations are performed. By providing a function for reporting to the center before the end of the battery life, the system can be operated more smoothly.

  Also, the large-capacity capacitor must not be charged beyond the withstand voltage. When charging by adjusting the voltage by the DC / DC converter, charging does not exceed the withstand voltage. However, in order to simplify the circuit, when the output from the solar cell is connected to the large-capacity capacitor in series only with a diode, the withstand voltage may be exceeded, so a bypass circuit is required. The bypass circuit bypasses the current before exceeding the withstand voltage of the large-capacity capacitor, and prevents charging beyond the withstand voltage.

  The bypass circuit needs to bypass the maximum output current of the solar cell and generates heat when fully charged. There are also large capacitors near the bypass circuit, and it is not desirable that the bypass circuit generate heat for a long time. Therefore, it is desirable to have a circuit configuration in which the bypass circuit is eliminated and charging is performed with a voltage equal to or lower than the withstand voltage only by the DC / DC converter. However, since the withstand voltage of the large capacity capacitor is low, it may be used by connecting in series. In that case, even if the output voltage of the DC / DC converter is adjusted to the sum of the withstand voltage of the large capacity capacitor, A bypass circuit is still necessary because the capacitor may be charged with overvoltage if the voltage balance of the capacitor is lost.

  In order to prevent the bypass circuit from generating heat when fully charged, the output voltage of the DC / DC converter needs to be lower than the sum of the set voltages of the bypass circuits, not the sum of the withstand voltages.

According to the power supply device for a terminal network control device according to the present invention, it is possible to obtain an independent small-sized solar battery power source that does not require power supply work even in a terminal network control device using a mobile phone network with high power consumption. it can. In addition, a lifetime of 10 years or more can be expected under most operating conditions, and there is no need for maintenance such as battery replacement. In other words, in a system that measures the monthly usage of electricity, gas, etc. at the customer's home that the power company or gas company has a contract with, the data transmission is operated during a free time such as at night on a preset meter reading day. Yes, it does not regularly transmit data, and the NCU does not require a long time for meter reading, so the operation rate on the meter reading day is also very low. Is short and the utilization rate is extremely low. The present invention relates to a solar cell power source, a large-capacity capacitor for storing and supplying electric power obtained by the solar cell power source, and a power source backup for a terminal network control device when the large-capacity capacitor cannot supply electric power. By defining the capacity of the lithium battery and the power generation capacity and storage capacity of the solar battery power source and the large capacity capacitor, a power supply device suitable for a system with a very low operating rate can be configured.

  Embodiments of a power supply apparatus for a terminal network control apparatus according to the present invention will be described below with reference to the drawings. A block diagram of an embodiment of a power supply device for a terminal network control device according to the present invention is shown in FIG. The telemeter system to which the power supply device for the terminal network control device is applied may be the same as that shown in FIG. 3 except for the NCU power supply device, and the description of the system will be omitted.

  A power supply device 10 shown in FIG. 1 uses a solar cell 9 as a power source, uses a large-capacity capacitor (hereinafter abbreviated as “capacitor”) 11 as a storage element, and has a lithium battery 12 that compensates for power shortage of the capacitor 11 as a spare battery. Power supply. Although the capacity of the capacitor 11 is reduced with the lapse of time, the capacitor 11 does not deteriorate much due to the number of charge / discharge, and can function for 10 years. The capacity of the capacitor 11 is set with a margin in bad weather and standard conditions.

  When the capacitor 11 falls below a certain voltage, such as at the start of use or when the terminal network control device operates above the standard condition, the power supply is switched from the lithium battery 12 as a spare battery to compensate for the power shortage. To work.

  Although the battery is hardly consumed under the standard conditions, the lithium battery 12 may be consumed when the terminal has severe operating conditions or when a large number of temporary operations are performed. By providing a function for reporting to the center before the end of the life of the lithium battery 12, the telemeter system can be operated more smoothly.

  In addition, as described above, when the output from the solar cell 9 is connected to a large-capacity capacitor in series with only a diode, the withstand voltage of the capacitor is exceeded, so that the current is bypassed before the withstand voltage is exceeded. A bypass circuit is required to prevent 11 from being charged beyond the withstand voltage. In order to avoid overcharging when the voltage balance of each capacitor is lost and to prevent the bypass circuit from generating heat when fully charged, the output voltage of the DC / DC converter is not the sum of the withstand voltage. The voltage is set lower than the sum of the set voltages of the bypass circuits.

  A circuit example of the embodiment of the present invention is shown in FIG. The output from the solar cell 9 is connected to the charge control unit 13. The charge control unit 13 charges the capacitor 11 with the output power from the solar cell 9 through the diode 17 and the DC / DC converter 18 that prevent backflow to the solar cell 9.

  The terminal network control apparatus connected to this embodiment is 3V operation, and the capacitor 11 connects two 2.5V withstand voltage products 11a and 11a in series. The series capacitors 11a and 11a are provided with bypass circuits 19a and 19a, respectively. Each bypass circuit 19a includes a shunt regulator and a transistor. The set voltage of the bypass circuit 19a is set to a value not exceeding 2.5V of the withstand voltage of each capacitor 11a. This configuration and setting is an extreme example, but even if one capacitor 11a is fully charged by 2.5V and the other capacitor 11a is charged from 0V, it is already fully charged. Since the bypass circuit operates to bypass the current, the fully charged capacitor will not be charged beyond the withstand voltage, and the empty capacitor will be charged with the current through the bypass circuit.

  Further, in order to avoid unnecessary heat generation at the time of full charge, the output voltage of the DC / DC converter 18 of the charge control unit 13 is set to 4.9 V which is smaller than 2.5V + 2.5V = 5.0V. By this setting, the bypass circuit 19 does not work at full charge, and unnecessary heat generation is suppressed.

  The switching unit 14 serves to connect the lithium battery 12 when the capacitor 11 is not charged. In the present embodiment, the threshold is set to 3.5 V in consideration of the capability of the output unit 15 in the subsequent stage and the load condition of the terminal network control device 23. The voltage detection unit 20 in the switching unit 14 detects the voltage of the capacitor 11, and the FET (field effect transistor) 21 in the switching unit 14 is used as a power source in the case of full charge from 3.5 V to 4.9 V. Is off. When the voltage of the capacitor 11 changes from 0V to 3.5V, the FET 21 is turned on to supply the lithium battery 12 as a power source. In this embodiment, two lithium batteries 12 are about 6V in series, and therefore a diode 22 is inserted to prevent backflow to the capacitor side.

  The output unit 15 is composed of a DC / DC converter, and outputs a voltage suitable for the terminal network control device 23 to be connected.

  The battery life detection unit 16 determines the battery life of the lithium battery 12. When it is determined that the service life is reached, the terminal network control device 23 must finally notify the center device 1. For this purpose, there is a method of adding a signal line to the terminal network control device 23. However, in this embodiment, the output unit 15 is controlled to intentionally lower the output voltage to about 2.4 V, and the terminal network control device. 23, the battery voltage drop notification is made.

  Next, in this embodiment, the grounds for using the capacitor 11 and the lithium battery 12 together will be described. In this embodiment, the solar cell 9 has an output of 3 watts and the capacitor 11 has 700 farads in which two 1400 farads 11a and 11a are connected in series. The panel of the 3-watt solar cell 9 is about 150 mm × 250 mm even in a general polycrystalline solar cell. The capacitor 11 is also large enough to fit in the battery storage unit of the terminal network control device 23 that uses a large number of batteries. These power supplies are of a size that does not cause a problem as a power supply for the terminal network control device 23.

  In the present embodiment, the amount of power that can be stored in the capacitor 11 and used as a power source is 700 farads from 4.9 V to 3.5 V, so that it is about 1 watt hour from the calculation.

  The terminal network control device 23 is assumed to be 15 milliwatts during standby and 1.5 watts during operation. As an operating condition, it is assumed that each terminal under operation is easily operated for one minute. For example, if the terminal network control device 23 having 10 terminals under its control performs meter reading once a month, the operation time of the month is 10 minutes.

  The operation of the power supply device during standby will be described. If the charging power is 1 watt hour, it can operate in a standby state for about 2 days even if the solar cell 9 is not connected.

  The solar cell 9 generates power not only with direct sunlight but also with diffused light. Even when it is cloudy, about one third of the power can be generated and there is about 1 watt. Therefore, even this is sufficiently higher than the standby power of the terminal network control device 23 and the capacitor 11 can be charged. In addition, the amount of power generated by the solar cell 9 when it becomes very dark, such as rain or snow, is 1/10 or less of that on a sunny day. However, even if the power generation amount is 1/100, it is 30 milliwatts, so it is difficult to charge the capacitor 11. However, in most cases, the standby power of the terminal network control device 23 can be covered. The voltage can be maintained. From these facts, assuming that the voltage of the capacitor 11 can be maintained from sunrise to sunset at worst, it can operate for about 4 days in a standby state.

  Next, the charging capability of the power supply device will be described. It is charged from 3.5V to 4.9V except when starting to use. Since the charge amount stored in the capacitor 11 is about 1 watt hour, it can be charged within one hour when it is fine. Even when it is cloudy, the charging is completed within a few hours. In this embodiment, the required amount of charge is about 1 watt hour at the maximum, so that the solar cell 9 with an output of 3 watts is sufficient.

  Next, the operation of the power supply device will be described. Normally, the meter reading operation is performed on the order of several times a month. In the system of the present embodiment, the cycle of charging and recovering the electric power discharged at night from the morning is repeated, and therefore, the meter reading cycle is basically irrelevant whether it is once a month or twice a month. It is assumed that daily meter reading is not realistic. If there are more subordinate terminals, the operation time for one meter reading increases proportionally, which is a problem.

If the meter reading operation is performed in the daytime, the battery is sequentially charged, which is convenient. However, if the meter reading operation is performed at night, only power is consumed. However, since it is difficult to condition the operation, it is assumed that the meter is read at night.
The standby state consumes about 0.25 watt-hours overnight. If the remaining 0.75 watt hour covers the meter reading operation, the operation is about 30 minutes, that is, the number of terminals under the terminal network control device 23 is 30.

  From the above, in this embodiment, the standard condition that can be operated without using the lithium battery 12 is that it operates for four days in standby, and the operation condition is under the control of the terminal network controller 23. Up to 30 terminals.

  Of course, even if it is used under the above conditions, the charge of the capacitor 11 disappears if an adverse condition such as the meter readings overlap after 4 days of bad weather, the lithium battery 12 guarantees the operation. It is rare that these adverse conditions overlap, and the lithium battery 12 should not be consumed so much. However, if the battery is exhausted, a notification will be sent to the center side device 1 and there will be no trouble in operation.

Here, the case where the lithium battery 12 is not provided is considered. When the lithium battery 12 is not provided, the terminal network control device 23 is turned off when the charge of the capacitor 11 is exhausted. Therefore, it is necessary to be able to supply power even when adverse conditions overlap. In other words, the system similar to the present embodiment must be able to perform meter reading of 30 terminals under the control of bad weather for 4 days.
In such a case, it is necessary to simply double the capacitance of the capacitor 11 in order to ensure the meter reading operation. However, in such a response, the doubled capacitor does not enter the battery storage part of the terminal network control device 23 as a whole, so it is necessary to provide a separate housing, and the number of expensive capacitors is doubled, resulting in a cost reduction. Will increase significantly and the merchantability will decrease. It is also conceivable that the condition becomes worse than the worst condition. It is also possible that irregular operations are entered in terminal tests. Thus, it can be seen that the measure for doubling the capacitance of the capacitor 11 is over-specification due to an event that occurs rarely. It is understood whether the merit of using the capacitor 11 and the lithium battery 9 according to the present invention is great.

  The present invention is not limited to the above embodiment, and it is needless to say that many modifications and changes can be made to the above embodiment within the scope of the present invention.

The block diagram which shows schematic structure of the power supply device for terminal network control apparatuses of this invention. The circuit diagram which shows one Example of the power supply device for terminal network control apparatuses shown in FIG. The system block diagram of the terminal network control apparatus using radio | wireless communication. The system block diagram of the terminal network control apparatus using the conventional communication line.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Center side apparatus 2 Communication network 4 Meter 5 Wireless base station 6 Wireless communication 7 Mobile phone wireless module 9 Solar cell 10 Power supply device 11 (11a, 11a) Large capacity capacitor 12 Lithium battery 13 Charge control part 14 Switching part 15 Output part 16 Battery Life Detection Unit 17 Diode 18 DC / DC Converter 19 (19a, 19a) Bypass Circuit 20 Voltage Detection Unit 21 FET
22 Diode 23 Terminal network controller

Claims (4)

A terminal network control device which is a master unit wirelessly connected to the center side device via a mobile phone line;
A telemeter system comprising a plurality of slave units connected to the master unit and a meter connected to the slave unit,
The plurality of slave units transmit monthly meter reading data of the meter to the terminal network control device, and the terminal network control device transmits the meter reading data to the center side device by the wireless communication. A power supply device for the terminal network control device of a telemeter system that performs remote meter reading of the meter,
The center side device and the terminal network control device perform wireless communication via the mobile phone line,
The power supply device includes a solar cell power source, a large-capacity capacitor for storing and supplying electric power obtained by the solar cell power source,
A lithium battery for performing power backup of the terminal network control device when the large-capacity capacitor cannot supply power; and
The lithium battery has a capacity capable of supplying power other than the power required for the wireless communication of the terminal network control device for 10 years,
The solar cell power supply and the large-capacity capacitor each have a power generation capacity and a storage capacity capable of storing electric power for executing the remote meter reading for 4 days when the large-capacity capacitor is fully charged on a clear day. Power supply for control device The power supply device for a terminal network control device according to claim 1,
A power supply device for a terminal network control device, comprising battery life detection means for detecting the arrival of the life of the lithium battery and reporting the fact to the center. The power supply apparatus for a terminal network control device according to claim 1 or 2,
The large-capacity capacitor is formed by connecting a plurality of capacitors in series, and each of the capacitors is provided with a bypass circuit for preventing overvoltage, and the charging voltage to the large-capacity capacitor is the voltage of each bypass circuit. A power supply apparatus for a terminal network control apparatus, wherein the power supply apparatus is controlled to be lower than a sum of bypass setting voltages. The power supply device for a terminal network control device according to claim 1,
A charge control unit that controls charging of the electric power obtained by the solar cell to the large-capacitance capacitor; and the large-capacity capacitor and the lithium that are connected to the charge control unit and that correspond to an output voltage of the large-capacity capacitor A switching unit that switches between and outputs one of the batteries; and the terminal network control device that is connected to the switching unit and is connected to the switching unit, and can output the battery life information according to the battery life of the lithium battery. And a power supply device for a terminal network control device.

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