JP2004328866A - Uninterruptible power supply unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To offer an uninterruptible power supply unit which can estimate an appropriate charge time and besides can reduce the size of its power unit by reducing a mounting space in the power unit. <P>SOLUTION: This uninterruptible power supply unit is equipped with a battery charge control circuit 9 which switches, while it suppresses a power supply by the receiption of a system OFF signal from a system at the destination of the power supply, the charge current of a battery 11 into a current of a smaller value than that of the charge current supplied to the battery 11 when it receives a system-on signal. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an uninterruptible power supply employing a battery backup, and more particularly to an uninterruptible power supply capable of reducing the size and cost of a power supply unit while satisfying charging of a battery.
[0002]
[Prior art]
Conventionally, there is an uninterruptible power supply of this type provided to a POS (point of sale information management) system as shown in FIG.
[0003]
In the illustrated uninterruptible power supply, a power supply unit 100 that supplies power to the system converts a commercial AC (AC) power taken from a plug 1 into 24 VDC (direct current) by an AC / DC converter 7 while generating AC / DC. The DC converter 8 generates a system backup voltage and a battery charging voltage. The battery charging voltage charges the battery 11 via the battery switching circuit 10 by the battery charging circuit 109. The battery switching circuit 10 connects the battery 11 to the DC 24 V supply circuit to form an uninterruptible power supply when the commercial AC power supply is cut off.
[0004]
Next, referring to FIG. 3 and FIG. 4, charging of the battery 11 in response to an “ON / OFF (ON / OFF) signal” of a switch in the power supply destination system will be described.
[0005]
When the power switch 3 of the power supply unit 100 changes from the “OFF” connection open state to the “ON” closed state, charging current is supplied to the battery 11 and continues until the power switch 3 is turned “OFF”. The AC / DC converter 7 is controlled so that a switch in the power supply destination system is turned “ON / OFF”, and normally there is no output when the switch is “OFF”. When the power switch 3 is “ON” and the switch “ON” signal is received from the power supply destination system, the AC / DC converter 7 supplies DC power to the system and also supplies the cooling fan 14 of the power supply unit 100 that generates heat. The cooling fan 14 is turned on by supplying DC power, and is driven.
[0006]
[Problems to be solved by the invention]
In the conventional uninterruptible power supply described above, there is a problem that it is necessary to increase the mounting space in the power supply unit, and therefore, it is necessary to increase the size of the power supply unit.
[0007]
The reason is that in a normal power supply destination system, the battery is continuously charged at a constant current value to a full charge state while the power supply unit is connected to the commercial AC power supply regardless of "ON / OFF", thereby setting the commercial AC power supply. This is because sufficient power is immediately supplied to the system in the event of a power failure. With this configuration, while the system is “OFF”, the battery needs to be charged in a natural air-cooled state in which the cooling fan is stopped in terms of quietness (CS (customer satisfaction)). Due to the stoppage of the cooling fan, a rise in component temperature due to a loss in power supplied to the AC / DC converter of the system backup power supply and the circuit for charging the battery that is operating even when the system is “OFF” increases. In order to suppress the rise in the temperature of the components, it is necessary to employ components having a greater heat radiation effect or to adopt a heat radiation plate of a larger size as compared with the design when the system is "ON".
[0008]
For example, in a battery charging circuit, when the voltage is approximately 27 V and the charging current is 0.3 A, the charging power is approximately 8.1 W. If the efficiency of the battery charging circuit is 70%, the charging circuit will generate approximately 3.5W of power loss. In this case, the battery can be fully charged in about 12 hours, but in order to maintain the temperature below the rated temperature of the component, it is necessary to increase the size of the component or provide a large-sized heat sink.
[0009]
On the other hand, if the charging current of the battery is set to one third of 0.1 A in order to suppress the temperature rise of such components, the charging power is approximately 2.7 W. Therefore, the power loss can be suppressed to about 1.2 W by this charging circuit. That is, it is possible to assemble the device with small parts and a heat sink having a small size. However, full charging cannot be performed unless charging time is expected to be about 24 hours.
[0010]
It is an object of the present invention to provide an uninterruptible power supply capable of solving the above-described problems, allowing an appropriate charging time, reducing a mounting space in a power supply unit, and reducing a size of the power supply unit. That is.
[0011]
[Means for Solving the Problems]
The uninterruptible power supply according to the present invention receives the system OFF (OFF) signal from the power supply destination system to the power supply unit and receives the system ON (ON) signal while charging the battery while the power supply is suppressed. A battery charge control circuit that switches to a smaller current value than the charge current supplied to the battery when the battery is running.
[0012]
For example, in the case of a 24-hour POS system, the “ON” state frequently or continuously during a busy period with many customers, but the “OFF” state continues for a long time when the customers are idle. With the above configuration under such conditions, the time until full charge is short in the "ON" state during one prosperity, and long in the "OFF" state during the off-peak time. The consumption can be reduced, and the size of the component and the size of the heat sink can be reduced.
[0013]
It is preferable that the charging current value in a state where the system OFF signal is received be a minimum current value at which the battery can be fully charged. Further, the component for generating the DC power supplied from the commercial AC power to the power supply destination system may have a size based on heat generation and heat radiation in accordance with the generation ratio of the system OFF signal and the system ON signal.
[0014]
Similarly, the heat radiating plate of the power supply unit that generates the DC power supplied from the commercial AC power supply to the power supply destination system is configured to generate heat of the power supply unit and the heat radiating plate according to the generation ratio of the system OFF signal and the system ON signal. The size based on the heat radiation is effective in reducing the mounting space in the power supply unit and the size of the power supply unit.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0016]
FIG. 1 is a functional block diagram showing an embodiment of the present invention.
[0017]
In the illustrated uninterruptible power supply, an inlet 2 for connecting an AC plug 1, a power switch 3, a filter 4, a smoothing circuit 5, a power factor improvement circuit 6, AC / DC converters 7, 8, a battery charge control circuit 9, a battery A power supply unit 15 including a switching circuit 10, a DC / DC converter 12, a connector 13, and a cooling fan 14 and a battery 11 connected to the battery switching circuit 10 are provided.
[0018]
The AC plug 1 supplies commercial AC power such as AC (alternating current) 100 V to the power supply unit 15 of the uninterruptible power supply via the inlet 2. The power switch 3 forms a closed circuit by "ON" and supplies commercial AC power to the internal circuit. The internal circuit is connected to AC / DC converters 7 and 8 via a series circuit including a filter 4, a smoothing circuit 5, and a power factor improvement circuit 6.
[0019]
The power that has passed through the filter 4 and the smoothing circuit 5 in the “ON” state of the power switch 3 is sent to the power factor improvement circuit 6 and the battery switching circuit 10. The power factor improving circuit 6 is provided reflecting recent domestic and overseas harmonic regulations. However, the provision of the power factor correction circuit may be omitted in a small power device or a device not regulated.
[0020]
The AC / DC converter 7 generates a main power supply DC voltage “+24 V” used in the system while receiving the “ON” signal from the system. This power is supplied to a device such as a printer, for example. The AC / DC converter 8 generates a DC voltage “+ 5VSB” for system backup (SB) regardless of the system ON / OFF signal. At the same time, AC / DC converter 8 generates a voltage for charging battery 11.
[0021]
The battery charging control circuit 9 receives a voltage for charging the battery from the AC / DC converter 8 and supplies a charging current corresponding to an “ON / OFF” signal received separately from the system to the battery switching circuit 10. The battery switching circuit 10 detects “ON” of the AC power from the AC power transmitted from the smoothing circuit 5 and supplies the charging current output from the battery charging control circuit 9 to the battery 11. When the AC power is extinguished and the AC power is turned “OFF”, the battery switching circuit 10 connects the battery 11 to the 24 V supply circuit of the DC power supply destination system.
[0022]
When receiving the “ON” signal from the system, the DC / DC converter 12 generates a DC voltage “+5 V, +3.3 V, −12 V, +12 V, etc.” used in the logic of the system. The cooling fan 14 is supplied with the output “+12 V” of the DC / DC converter 12 so as to operate only while the system is “ON”.
[0023]
Next, the main operation functions of the illustrated circuit will be described with reference to FIGS.
[0024]
As described above, the difference between FIG. 1 and FIG. 3 is that while the battery charge control circuit 9 is receiving the battery charging voltage from the AC / DC converter 8, it responds to the "ON / OFF" signal separately received from the system. The charging current is supplied to the battery switching circuit 10.
[0025]
The power supply unit 15 is initially in an “OFF” state in which the AC plug 1 is plugged into the commercial AC power supply, the battery 11 is connected, and the power switch 3 is opened, and the system ON / OFF received from the power supply destination system The signal is a system OFF signal whose circuit is opened. If this is the case, no operation starts.
[0026]
Here, when the power switch 3 of the power supply unit 15 is changed from “OFF” to “ON”, the AC power is supplied to the AC / DC converter via the filter 4 and the smoothing circuit 5, and via the power factor improvement circuit 6. 7, 8 and, on the other hand, the battery switching circuit 10. The AC / DC converter 7 is controlled by a system ON / OFF signal based on a switch of a power supply destination system, and there is no output in the state of the system OFF signal. The AC / DC converter 8 generates a DC voltage “+ 5VSB” and generates a voltage for charging the battery 11 irrespective of the system ON / OFF signal.
[0027]
Since the battery charge control circuit 9 having received this voltage has received the system OFF signal, the battery charge control circuit 9 supplies a charge current with a small current value to the battery switching circuit 10. Since the battery switching circuit 10 receives the notification of the AC power supply “ON” by receiving the supply of the AC power from the smoothing circuit 5, the charging current due to the small current value from the battery charging control circuit 9 is supplied to the battery 11. Power is supplied until the power switch 3 is turned “OFF”. This is a state where the power switch 3 is "ON" and the system ON / OFF signal is "OFF" in FIG.
[0028]
Here, a case where a switch ON signal is received from the power supply destination system will be described.
[0029]
First, one AC / DC converter 7 receives a switch ON signal, so that a DC power supply “+24 V” serving as a main power supply in the power supply destination system is generated, and a DC voltage “+5 V, + 3.3V, -12V, + 12V, etc. " This DC voltage “+12 V” operates the cooling fan 14.
[0030]
On the other hand, since the battery charge control circuit 9 receives the system ON signal, it switches the small current value and supplies the battery switching circuit 10 with the charging current based on the large current value. Since the battery switching circuit 10 receives the notification of the AC power supply “ON” by receiving the AC power supply from the smoothing circuit 5, the charging current due to the large current value from the battery charging control circuit 9 is supplied to the battery 11. The power is supplied until the switch 3 is turned "OFF" and the AC power supply is turned "OFF", or until the system ON signal is switched to the system OFF signal. This is a state where the power switch 3 is “ON” and the system ON / OFF signal is “ON” in FIG.
[0031]
For example, in the case of a POS system in a 24-hour store, the “ON” state is frequent or continuous when there are many customers, but compared to the case where the “OFF” state continues for a long time when customers are off. It can be said that week days are relatively short. With the above configuration under such conditions, the time until full charge is short in the "ON" state during one prosperity, and long in the "OFF" state during the off-peak time. It is likely that the consumption will be reduced and the dimensions of the components and the size of the heat sink can be significantly reduced.
[0032]
The charging current value in the state where the system OFF signal is received can be the minimum current value at which the battery can be fully charged. In addition, the component that generates the DC power supplied from the commercial AC power to the power supply destination system can have a size based on heat generation and heat radiation in accordance with the generation ratio of the system OFF signal and the system ON signal.
[0033]
Similarly, the heat radiating plate of the power supply unit that generates the DC power supplied from the commercial AC power supply to the power supply destination system is configured to generate heat of the power supply unit and the heat radiating plate according to the generation ratio of the system OFF signal and the system ON signal. The size based on the heat radiation is effective in reducing the mounting space in the power supply unit and the size of the power supply unit.
[0034]
In the above description, the function of switching the magnitude of the charging current by the system ON / OFF signal is provided to the battery charge control circuit, and when the system OFF signal is received as shown in FIG. The current value was reduced so as to operate so that the chargeable minimum value was obtained. However, when the condition that the battery of the uninterruptible power supply is always fully charged is not set, the battery charge control circuit is set to cut off the battery charge when receiving the system OFF signal. Is also good.
[0035]
In the above description, reference is made to the illustrated functional blocks and procedures, but changes such as allocation or separation of procedures by separation / merging of functions are free as long as the above functions are satisfied, and the above description limits the present invention. However, the present invention is also applicable to general uninterruptible power supplies that have a backup battery in the commercial AC power supply and charge the backup battery with the commercial AC power supply.
[0036]
【The invention's effect】
As described above, according to the present invention, it is possible to obtain an effect of suppressing an increase in the size of a power supply unit provided with a heat radiation measure.
[0037]
The reason is that the battery charging control circuit has a function of switching the charging current in response to a system ON / OFF signal from the power supply system, and reduces the charging current of the battery when the system OFF signal is received. For this reason, the loss in the power supply unit is reduced and the heat generation is also reduced, so that it is not necessary to increase the size of components provided for heat dissipation measures or the size of the heat sink.
[0038]
In addition, since the size of the components and the size of the heat radiating plate do not increase, the size of the power supply unit does not need to be increased. Furthermore, since the size of the power supply unit, the components, and the heat radiating plate are not increased, it is possible to suppress an increase in the cost of the power supply unit.
[Brief description of the drawings]
FIG. 1 is a functional block diagram showing an embodiment of the present invention.
FIG. 2 is a time chart illustrating a change in a charging current in FIG. 1;
FIG. 3 is a functional block diagram showing an example of the related art.
FIG. 4 is a time chart for explaining a change in charging current in FIG. 3;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 AC plug 2 Inlet 3 Power switch 4 Filter 5 Smoothing circuit 6 Power factor improvement circuit 7, 8 AC / DC converter 9 Battery charge control circuit 10 Battery switching circuit 11 Battery 12 DC / DC converter 13 Connector 14 Cooling fan 15 Power supply unit

Claims (6)

In an uninterruptible power supply employing a battery backup, a charging current supplied from a commercial AC power supply and supplied to a battery is supplied to a power supply destination system in a state in which a system “off” signal indicating a halt of the power supply destination system is received. An uninterruptible power supply device comprising: a battery charge switching circuit that switches to a current value reduced from a current value when a system “ON” signal indicating operation of the system is received. 2. The uninterruptible power supply according to claim 1, wherein a charging current value in a state where a system "OFF" signal is received is a minimum current value at which the battery can be fully charged. 2. The component according to claim 1, wherein the component that generates the DC power supplied from the commercial AC power to the power supply destination system is based on heat generation and heat radiation according to the generation ratio of the system “OFF” signal and the system “ON” signal. An uninterruptible power supply device. 2. The power supply unit according to claim 1, wherein the heat radiating plate of the power supply unit that generates a DC power supply supplied from the commercial AC power supply to the power supply destination system follows a generation ratio of the system "OFF" signal and the system "ON" signal. An uninterruptible power supply having a size based on heat generation of the heat sink and heat radiation of the heat sink. 2. The system according to claim 1, wherein a charging current value for each of a system "off" signal and a system "on" signal set based on a generation state of the system "off" signal and the system "on" signal is transmitted. Uninterruptible power supply. 6. The charging current value in a state where the system "ON" signal is received according to claim 5, wherein a longer charging time of the system "ON" signal and a system "OFF" signal are received. An uninterruptible power supply device characterized in that a smaller charging current is set to a charging current value in a state in which the system “off” signal is longer for a longer time.

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