JP2012152050A - Cell power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cell power supply device for inhibiting power interruption to a load when exchanging a battery and capable of serving as a replacing cell power supply device for a current battery until it is replaced because of deterioration of output voltage.SOLUTION: A cell power supply device for supplying power to a battery driven load, includes: at least two power supply systems having a switch and a battery serially connected, for connecting the load in parallel; a voltage detection part connected to these power supply systems in parallel, for detecting the drop of the inter-terminal voltage of the load to a prescribed setting value and outputting a voltage drop detection signal; and a switch controlling part for performing switching on or off of the power source voltage so as not to shutdown the power source voltage applied to the load even when switching on the other power system in a state when the power system switch with dropped output voltage is switched on depending on the voltage drop detection signal output from the voltage detection part.

Description

  The present invention relates to a battery power supply device, and more particularly to power supply control during battery replacement.

  One type of field device that constructs a process control system is one that is configured to be driven by a battery. FIG. 3 is a block diagram showing an example of a power supply system in such a field device.

  In FIG. 3, the field device 1 is driven by a battery 2 and has a sensor function for measuring a physical quantity such as temperature and pressure, and an actuator function such as valve opening / closing control. Not shown. In addition, the field device 1 is provided with a wireless communication unit 1a for performing wireless communication with an external host system (not shown).

  The voltage detector 3 measures the output voltage of the battery 2 to detect a voltage drop, and clearly indicates to the outside that the output voltage of the battery 2 has fallen below a predetermined set value. The field device 1 and the battery 2 are connected in parallel. The set value is set slightly higher than the lower limit value of the drive voltage at which the field device 1 can operate stably.

  In such a configuration, the voltage drop detection result of the voltage detection unit 3 is notified to an external host system through the wireless communication unit 1a as alarm information, for example, as necessary.

  When the output voltage of the battery 2 falls below a predetermined set value set in advance, the worker temporarily stops the power supply from the battery 2 to the field device 1 and replaces the battery 2. I do.

  By the way, the installation location of field devices such as temperature transmitters and pressure transmitters in process control systems is the source of wells such as oil and gas in remote areas such as deserts and seas, high places such as plant chimneys, and high temperatures. It may be a dangerous place filled with volatile gas.

  It is difficult to immediately replace the battery 2 for driving the field device 1 installed in these places when the voltage detection unit 3 detects a decrease in the output voltage.

  In addition, these plants are premised on continuous operation over a long period of time, and it is not preferable to replace batteries at any time other than when the plant is stopped for regular maintenance.

  As described above, due to the nature of the field device installation environment, plant operating requirements, etc., the operation stop time from when the power supply to the field device is stopped until the battery is replaced and the power supply to the field device is restarted is relatively long. There is also a risk.

  In the case of a lithium battery generally used as a primary battery, the output voltage does not decrease to near the discharge limit, but the time from when the output voltage decrease is detected until the operation limit of the device is reached is, for example, about 1 hour. And relatively short. Therefore, lithium battery backup batteries and supercapacitors are equipped, and even if the power supply from the lithium battery stops, it is possible to supply power for a while, but in general these power supplies The capacity is small, and the power supply time to the equipment is limited.

  Therefore, for example, as shown in FIG. 4, a plurality of n power supply systems in which the batteries 41 to 4n, the diode 50, and the switches 71 to 7n are connected in series, and the remaining amount of the batteries 41 to 4n are reduced to a predetermined level. A plurality of n remaining battery level detection circuits 51 to 5n that detect detection signals and output detection signals, and supply the optimum battery output to the device main body 60 based on the detection signals of the remaining battery level detection circuits 51 to 5n. The battery selection circuit 50 that outputs a signal for selectively turning on / off the switches 71 to 7n as described above, and proposes an automatic battery power switching device that prevents power interruption even when the battery is replaced. Has been.

  Patent Document 1 describes a technology of an automatic battery power supply switching device shown in FIG. 4 that is configured so that power supply is not interrupted even when a battery is replaced.

JP-A-7-194014

  However, according to the conventional configuration shown in FIG. 4, the power loss does not occur when the battery is replaced, but the remaining amount of the batteries 41 to 4n has decreased to a predetermined level in each of the plurality of n power supply systems. Since a plurality of n remaining battery level detection circuits 51 to 5n for detecting this and outputting detection signals are provided, the circuit configuration of the apparatus becomes complicated and the number of parts increases, making it difficult to reduce the size of the apparatus. There is a problem.

  The present invention solves such a problem, and an object of the present invention is to provide a battery power supply device that can prevent a power interruption from occurring during battery replacement with a relatively simple configuration.

In order to achieve such a problem, the invention according to claim 1 of the present invention is:
In a battery power supply that supplies power to a battery-driven load,
A switch and a battery connected in series, and at least two power systems connected in parallel with the load;
A voltage detection unit connected in parallel with these power supply systems, detecting that the voltage between the terminals of the load has dropped to a predetermined set value and outputting a voltage drop detection signal;
Based on the voltage drop detection signal output from the voltage detector, the power supply voltage applied to the load is not disconnected by turning on the switch of the other power supply system while the switch of the power supply system whose output voltage is reduced is on. Switch controller to control on and off,
Is provided.

The invention according to claim 2 is the battery power supply device according to claim 1,
The load is a field device for constructing a process control system.

The invention according to claim 3 is the battery power supply device according to claim 2,
The field device includes a wireless communication unit.

The invention according to claim 4 is the battery power supply device according to any one of claims 1 to 3,
The battery is a lithium battery.

  As a result, the load can be continuously driven without power interruption to the load during battery replacement.

  The battery whose output voltage has decreased can be replaced at any point in time until the output voltage of the current battery decreases and is replaced.

It is a block diagram which shows one Example of this invention. 2 is a timing chart illustrating the operation of FIG. 1. It is a block diagram which shows an example of the power supply system in the conventional field device. It is a block diagram which shows an example of the conventional automatic switching apparatus of a battery power supply.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention, and the same reference numerals are given to portions common to FIG. In FIG. 1, batteries 21 and 22 are the same, and are connected to supply power to the field device 1 via switches SW1 and SW2 connected in series, respectively. The voltage detection unit 3 and the switch control unit 9 are also connected in parallel with the field device 1.

  These batteries 21 and 22 may be battery packs in which a plurality of batteries are internally connected in series or in parallel. In comparison with the battery 2 of FIG. 3, the output voltage and the output current are equal to or greater than each other, and the output capacity is at least 1/2 or greater.

  The switches SW1 and SW2 have a self-holding function, and can maintain the on / off state without supplying holding power or by supplying a small holding power.

  The voltage detector 3 detects a decrease in the output voltage of the batteries 21 and 22. This voltage drop detection result is output to the switch control unit 9 and, if necessary, is notified to an external host system through the wireless communication unit 1a as alarm information, for example.

  The switch control unit 9 controls on / off of the switches SW1 and SW2, and is configured by, for example, a sequencer using a digital circuit or a software program that operates on a microcomputer.

The operation of FIG. 1 will be described.
First, the switch control unit 9 is driven so that the switch SW1 is turned on and the SW2 is turned off. Thereby, the field device 1 is driven by the output voltage V21 of the battery 21 (step S1).

  The voltage detector 3 detects a decrease in the output voltage V21 of the battery 21 that drives the field device 1. When it is detected that the output voltage V21 of the battery 21 has decreased below a predetermined set value set in advance, a voltage drop detection signal is output to the switch control unit 9 and alarm information is transmitted via the wireless communication unit 1a. To the external host system (step S2). Here, the set value is set slightly higher than the lower limit value of the drive voltage at which the field device 1 can operate stably.

  The switch control unit 9 keeps the switch SW1 on and also turns on the switch SW2 connected to the unused battery 22. Thereby, the field device 1 is driven by the output voltage V21 of the battery 21 and the output voltage V22 of the battery 22 (step S3).

  Subsequently, the switch control unit 9 turns off the switch SW1 connected to the battery 21 in which the output voltage V21 has decreased while keeping the switch SW2 on. Thereby, the field device 1 is driven by the output voltage V22 of the battery 22 (step S4).

  Thereafter, the worker replaces the battery 21 whose output voltage V21 has decreased with an unused one based on the alarm information notified to the external host system via the wireless communication unit 1a (step S5).

  At this time, since the field device 1 is continuously driven with the output voltage V22 of the new battery 22, the battery 21 does not need to be replaced quickly, and the output voltage V22 of the battery 22 decreases to a predetermined set value. It may be performed within the period until. Although the battery life may be shortened depending on the use environment and self-discharge, it is relatively long.

  Further, the voltage detection unit 3 detects a decrease in the output voltage V22 of the battery 22 that drives the field device 1. When it is detected that the output voltage V22 of the battery 22 has dropped below a predetermined set value set in advance, the voltage drop detection result is output to the switch control unit 9 and also as alarm information via the wireless communication unit 1a. To the external host system (step S6).

  The switch control unit 9 keeps the switch SW2 on, and also turns on the switch SW1 connected to the replaced unused battery 21. Thereby, the field device 1 is driven by the output voltage V21 of the battery 21 and the output voltage V22 of the battery 22 (step S7).

  Subsequently, the switch control unit 9 turns off the switch SW2 connected to the battery 22 in which the output voltage V22 is lowered while keeping the switch SW1 on. Thereby, the field device 1 is driven by the output voltage V21 of the battery 21 (step S8).

  Thereafter, the worker replaces the battery 22 whose output voltage V22 has decreased with an unused one based on the alarm information notified to the external host system via the wireless communication unit 1a (step S9).

  Thereafter, the sequence from steps S2 to S9 is repeated.

  As a result, when replacing a battery whose output voltage V21 or V22 has decreased with an unused battery, the drive power supply of the field device is not temporarily cut off as in the prior art, and is continuously operated over a long period of time. Therefore, it is possible to replace the battery without stopping the premise plant.

  Further, even if the voltage detection unit 3 detects a decrease in the output voltage V21 or V22 of the battery, it is not necessary to quickly replace the battery.

  In addition, in the present invention, by using a battery having an output capacity of approximately ½, actual life data in an actual operating environment can be obtained earlier in about half the period compared to the conventional one. The accuracy can be further increased.

  FIG. 2 is a timing chart for explaining the operation of FIG. 1, (a) shows a voltage drop detection signal of the voltage detector 3, and (b) shows on / off of the switch SW <b> 1 connected in series with the battery 21. (C) shows ON / OFF of the switch SW2 connected in series to the battery 22, and (d) shows the output voltage V21 of the battery 21 and the output voltage V22 of the battery 22 applied as drive voltages to the field device 1. Is shown.

  At time t1, the switch SW1 is on and the switch SW2 is off, and the output voltage V21 of the battery 21 is applied to the field device 1 as a drive voltage (step S1).

  When the output voltage V21 of the battery 21 decreases at time t2, a voltage decrease detection signal is output from the voltage detection unit 3 to the switch control unit 9 (step S2).

  Based on the voltage drop detection signal input from the voltage detector 3, the switch controller 9 holds the switch SW <b> 1 on and also turns on the switch SW <b> 2 connected to the unused battery 22. Thereby, the output voltage V21 of the battery 21 and the output voltage V22 of the battery 22 are applied to the field device 1 as drive voltages (step S3).

  At time t3, the switch control unit 9 turns off the switch SW1 while keeping the switch SW2 on. Thereby, the output voltage V22 of the battery 22 is applied to the field device 1 as a drive voltage (step S4).

  When the output voltage V22 of the battery 22 decreases at time t4, a voltage decrease detection signal is output from the voltage detection unit 3 to the switch control unit 9 (step S6). The battery 21 in which the output voltage V21 has decreased is replaced with an unused battery between time t3 when the decrease in the output voltage V21 is detected and time t4 when the decrease in the output voltage V22 of the battery 22 is detected. .

  Based on the voltage drop detection signal input from the voltage detector 3, the switch controller 9 keeps the switch SW <b> 2 on and also turns on the switch SW <b> 1 connected to the replaced unused battery 21. Thereby, the output voltage V21 of the battery 21 and the output voltage V22 of the battery 22 are applied to the field device 1 as drive voltages (step S7).

  At time t5, the switch control unit 9 turns off the switch SW2 while keeping the switch SW1 on. Thereby, the output voltage V21 of the battery 21 is applied to the field device 1 as a drive voltage (step S8). The battery 22 in which the output voltage V22 has decreased is replaced with an unused battery from time t5 when the decrease in the output voltage V22 is detected until the decrease in the output voltage V21 of the battery 21 is detected.

  In the above-described embodiment, an example of a battery power supply device for driving a field device has been described. However, the load is not limited to the field device, and it is useful as a battery power supply device for various devices using a battery as a drive power source. is there.

  Further, after determining that the data necessary for the life prediction can be accumulated, both the switches SW1 and SW2 may be turned on to connect the batteries in parallel, and the operation mode may be similar to that of using a conventional battery.

  As described above, according to the battery power supply device of the present invention, it is possible to prevent the occurrence of power interruption at the time of battery replacement with a relatively simple configuration, and the output voltage of the current battery can It can be exchanged at any point in time until it is lowered and exchanged, and is suitable as a battery power supply device with a load that requires continuous operation over a long period of time, such as a field device that constructs a process control system.

1 Field equipment (load)
1a Wireless communication unit 21, 22 Battery 3 Voltage detection unit 9 Switch control unit SW1, SW2 switch

Claims (4)

In a battery power supply that supplies power to a battery-driven load,
A switch and a battery connected in series, and at least two power systems connected in parallel with the load;
A voltage detection unit that is connected in parallel with these power supply systems, detects that the voltage between the terminals of the load has dropped to a predetermined set value, and outputs a voltage drop detection signal;
Based on the voltage drop detection signal output from the voltage detector, the power supply voltage applied to the load is not disconnected by turning on the switch of the other power supply system while the switch of the power supply system whose output voltage is reduced is on. Switch controller to control on and off,
A battery power supply device comprising:   The battery power supply device according to claim 1, wherein the load is a field device for constructing a process control system.   The battery power supply apparatus according to claim 1, wherein the field device includes a wireless communication unit.   The battery power supply device according to any one of claims 1 to 3, wherein the battery is a lithium battery.

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