JP2732325B2 - Battery backup DC supply - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery backup DC power supply, and more particularly, to an AC / DC converter for converting an AC voltage to a DC voltage, and a DC drive device driven by the DC voltage during an AC power failure. A battery for backing up the battery, and a switch unit for connecting or disconnecting the battery to or from the DC drive according to an instruction to drive and stop the DC drive, and to supply a direct current to the DC drive, The present invention relates to a battery backup DC supply device that charges a battery even when a DC drive device is stopped. In recent years, when an AC input has failed, for example, as shown in FIG. 2, a battery backup is required for a device that executes data comparison processing to a nonvolatile memory.

[0002]

2. Description of the Related Art Conventionally, there has been a battery backup DC supply device as shown in FIG. As shown in FIG. 1, the present apparatus includes an AC / DC converter 1 for converting an AC voltage to a DC voltage, a DC driving device 2 driven by a DC voltage,
A backup battery 3 for the DC driving device 2 at the time of AC power failure; a switch unit 5 for connecting or disconnecting the battery 3 to or from the DC driving device 2 in accordance with an instruction to drive and stop the DC driving device; It has a cooling unit 66 for cooling the DC converter 1 and a constant current unit 68 for supplying a charging current to the battery 3.

FIG. 7 shows the battery 3, the switch unit 5, the constant current unit 68 and the like shown in FIG. 6 in detail. As shown in the figure, the switch unit 5 is a relay, and includes an electromagnet 5a that performs excitation or demagnetization, and a movable unit 5b that is turned on or off by excitation or demagnetization.
The constant current circuit 68 includes a diode 8 as shown in FIG.
b, 8c, a transistor 8a, and a resistor 8r are mainly provided. Further, the DC driving device 2
A transistor 9a for performing an on / off operation based on a power on / off signal for instructing driving and stopping for the transistor 9a;
And a signal converter 9 for converting a power on / off signal into an appropriate current value.

In this example, normally, a 29 V DC converted by the AC / DC converter 1 is supplied to the constant current section 68.
Is converted into a charging current having a predetermined current value and supplied to the battery 3. Here, the charging current I _C can be calculated by the following equation. I _C = {(V _fb + V _fc ) −V _be } / R ₁ where V _fb and V _fc are the built-in voltages between the anodes and cathodes of the diodes 8b and 8c, and V _be is the transistor 8a.
Is the voltage between the base and the emitter, and R is the resistance value of the resistor 8r. Generally, in the case of a lead-acid battery, the charging current I _C
Is 0.25 × C (C is the capacity), and the capacity of the battery 3 is 5
If AH (capacity), the charging current I _C becomes 1.25 A.
This example operates as follows. When a power on signal, which is a driving instruction for the DC driving device 2, is output, the transistor 9a of the signal conversion unit 9 is turned on (conducting state). As a result, the electromagnet 5a of the relay of the switch unit 5 is in an excited state, the movable unit 5b can be moved, and the battery 3 is connected to the DC driving device 2, thereby coping with a power failure.

On the other hand, when a power off signal for instructing the DC drive device 2 to stop is output, the signal converter 9
The transistor 9a is turned off (disconnected state), the electromagnet 5a of the switch unit 5 is demagnetized, and the movable unit 5b disconnects the battery 3 from the DC driving device 2. In the conventional example, even if the DC driving device 2 is in a stopped state, the size I _C described above is supplied to the battery 3 via the constant current unit 68.
Is supplied to the battery 3. Therefore, the cooling unit 66 for cooling the AC / DC converter 1 needs to be controlled so that power is supplied even if the DC driving device 2 is in a stopped state. .

[0006]

As described above,
In the conventional example, the DC driving device 2 is stopped (po
(Wer off state), it is necessary to supply the charging current to the battery 3. In particular, when the number of the batteries 3 increases and there are N batteries 3, the magnitude of the current becomes 1.25 NA, and the AC / DC
The output capacity of the converter 1 increases, and as described above, it is necessary to cool the AC / DC converter 1 by the cooling unit 66. Even when the DC driving device 2 is stopped, the cooling unit 66 However, there is a problem that it is necessary to supply power and drive a cooling fan, for example.

Therefore, the present invention provides a method for controlling the charging current when the DC driving device 2 is stopped, since the battery is not used even if the AC power supply is interrupted. To provide an efficient, energy efficient, battery-backed DC supply with reduced power consumption, taking into account that the magnitude of the charging current does not need to be based on battery use It was made for the purpose of.

[0008]

In order to solve the above technical problems, the present invention provides an AC / DC converter 10 for converting an AC voltage to a DC voltage as shown in FIG. A battery 30 for backing up the DC drive device 20 driven by the DC voltage, a switch unit 50 for connecting or disconnecting the battery 30 to or from the DC drive device 20 in accordance with an instruction to drive and stop the DC drive device; In the battery backup DC supply device capable of charging the battery 30 even when the DC drive device 20 is stopped, when the drive of the DC drive device 20 is instructed, AC / DC
When there is an instruction to drive the cooling unit 60 that cools the converter 10 and the DC drive device 20, the charging current during driving is supplied to the battery 30, and when there is an instruction to stop the DC drive device 20, And an instruction-dependent constant current unit 80 that supplies a stop charging current having a current value smaller than the driving charging current to the battery 30.

[0009]

As shown in FIG. 1, when there is an instruction to drive the DC driving device 20, the switch unit 50 operates the AC / DC
The battery 30 is connected to the DC driving device 20 together with the DC voltage converted from the converter 10, and the DC voltage from the battery 30 is supplied to the DC driving device 20 to prepare for a power failure of the AC power supply. If there is a power failure, only the DC voltage from the
It will be supplied to the C drive device 20. In addition, when there is an instruction to drive the DC driving device 20, the instruction-dependent constant current unit 80 supplies a charging current at the time of driving to the battery 30.

On the other hand, when there is an instruction to stop the DC drive unit 20, the switch unit 50 disconnects the battery 30 from the DC drive unit 20, and the instruction dependent constant current unit 80 supplies the charging current at the time of power failure to the battery 30. Will be supplied. Here, the magnitude of the stop-time charging current is set to be smaller than the magnitude of the driving-time charging current. The reason for this is that when the DC driving device 20 is in a stopped state, the current from the battery 30 to be backed up is supplied to the DC driving device 20 even if the AC power supply is interrupted.
Is not used immediately, so that it is not necessary to supply a charging current of a driving charging current of a magnitude set on the assumption that the battery 30 is used. When the magnitude of the charging current is small, the DC / A
Since the calorific value of the C converter 10 is small, it is not necessary to supply power to the cooling unit 60 to cool the C converter 10, and the power of the power supply is reduced as a whole.

[0011]

Next, an embodiment of the present invention will be described. FIG. 2 shows an overall view of the battery backup DC supply device according to the embodiment. As shown in the figure, in the present embodiment, an AC / DC converter 1 for converting an AC voltage to a DC voltage, DC / DC converters 21 and 23 which are DC driving devices 2, and an AC power supply during a power failure. and N number of the battery units 13 ₁ to 13 _N to back up the DC / DC converter 21, 23, the DC / DC converter 21,
A power control unit 4 for instructing driving and stopping of the
When the DC / DC converters 21 and 23 are driven.
Cooling units 71, 72 for cooling converters 21, 23, etc.
73, 74 and AC according to an instruction from the power control unit 4.
Cooling unit 6 for cooling DC / DC converter 1;
Logic unit 22 driven by converters 21 and 23, respectively
And a volatile memory 24. FIG. 3 shows each of the battery units 131 to _{1 according} to the first embodiment.
13 _N.

As shown in FIG. 1, the battery unit includes a switch unit 5 for connecting or disconnecting the battery 3 to or from the DC driving devices 21 and 23 in response to an instruction from the power supply control unit 4. It has a transistor 9a for performing on / off operation based on a power on / off signal for instructing the drive device 2 to drive and stop, and a resistor for voltage adjustment. When the DC converters 21 and 23 are instructed to drive, the driving charging current is converted to the battery
When the DC drive devices 21 and 23 are instructed to stop, an instruction-dependent constant current unit 81 that supplies a stop-time charging current having a current value smaller than the driving-time charging current to the battery 3 is provided. Have The switch unit 5
Are an electromagnet 5a that is excited or demagnetized, and an electromagnet 5a.
a movable part 5b for connecting or disconnecting the battery 3 to or from the DC driving devices 21 and 23 in accordance with the excitation or demagnetization of
And Further, the instruction-dependent constant current section 81 mainly includes a transistor 81 as shown in FIG.
a, a constant current circuit including diodes 81e and 81f and a resistor 81g, and a constant current circuit mainly including a transistor 81b, diodes 81c and 81d, and a resistor 81h.

Next, the operation of the battery backup DC supply device according to this embodiment will be described. A power on signal is generated from the power supply control unit 4 and the DC drive device 2
When there is an instruction to drive 1 or 23, the signal is input to the base of the transistor 9a of the signal conversion unit 9, and the transistor 9a is turned on (on). Then, the switch unit 5
The electromagnet 5a is excited to move the movable part 5b to connect the battery 3 to the DC / DC converters 21 and 23, and to supply a DC current to the DC / DC converters 21 and 23 in preparation for a power failure of the AC power supply. Will be. At this time, the transistor 81a is always in a conductive state, and the sum of the current and the current passing through the transistor 81b is supplied to the battery 3 as a driving charging current. That is, the driving charging current I _C is as follows: I _C = {(V _fe + V _ff ) −V _bea } / R _g + {(V _fc + V _fd ) −V _beb } / R _h . However, V _fe , V _ff , V _fc and V _fd are diodes 8
1 e, 81 _f, 81 _{c, and} 81 _d are the internal voltages between the anode and the cathode, and V _bea and V _beb are transistors 81
a, a voltage between the base and emitter of 81b, R _g,
R _h is the resistance 81g, is a resistance value of 81h.

On the other hand, when a power off signal is generated from the power supply control unit 4 and a stop instruction is issued, the signal is input to the base of the transistor 9a of the signal conversion unit 9, and the transistor 9a is turned off (off state). Then, the electromagnet 5a of the switch unit 5 is demagnetized, and the movable unit 5b is turned off to shut off the battery 3 from the DC / DC converters 21 and 23. At the same time, the transistor 81b of the instruction-dependent constant current section 81 is turned off. Therefore, current flows through the battery 3 only through the transistor 81a which is always in a conductive state. Therefore, the stop-time charging current I _C supplied to the battery 3 is given by I _C = {(V _fe + V _ff ) −V _bea } / R _g . As compared with the case, a charging current having a smaller current value is supplied to the battery 3. This is the DC / DC
When converters 21 and 23 are stopped, for example, AC / D
Even if the AC input to the C converter 1 is interrupted, the DC / DC converters 21 and 23 do not need to be immediately backed up from the battery 3, so that a charging current of a magnitude that is assumed to be backed up immediately is supplied. It is not necessary to do it. Since the stop charging current supplied to the battery 3 is smaller than the driving charging current, the AC / DC converter 1 does not need to be cooled by the cooling unit 6, thereby reducing the power to be supplied. Will do.

FIG. 4 shows a battery unit according to a second embodiment. In this embodiment, the emitter of the transistor 82a and the collector of the transistor 82b are connected to each other with a resistor 82f interposed therebetween, as shown in the figure, instead of the instruction-dependent constant current unit 81 according to the first embodiment. It is provided so as to be performed. Also in this example, as in the first embodiment, the transistor 82a is always in a conductive state. DC / DC converters 21 and 2 which are DC driving devices
When a power-on signal for instructing the driving of the drive unit 3 is generated and the signal converted by the signal conversion unit 9 is output, the electromagnet 5a of the switch unit 5 is excited, the movable unit 5b moves, and the battery 3 is the DC / DC converter 21,
23 to prepare for a power failure of the AC power supply. At this time, the transistor 82b of the instruction-dependent constant current unit 82 is turned on, and therefore, the battery 3
The driving charging current I _C shown below is supplied. That is, I _C = {(V _fc + V _fd ) −V _be } / R ₁₂ ... R ₁₂ = R _e * R _f / (R _e + R _f ) where V _fc and V _fd are diodes 82c, respectively. a built-in voltage between the anode and cathode 82d, R _e, R _f represents resistance 82e, the resistance value of 82f.

On the other hand, when a power off signal for instructing the stop of the DC / DC converters 21 and 23 is input to the signal converter 9, the signal is changed to a corresponding signal and the switch 5
The electromagnet 5a is demagnetized, the movable part 5b moves, and the battery 3 is disconnected from the DC / DC converters 21 and 23 to be in a cutoff state. Further, the transistor 9a of the signal converter 9 is cutoff state, said instruction dependency transistor 82b of the constant current portion 82 becomes disconnected state, therefore, the battery 3, is stopped when the charging current I _C shown below Will be supplied. That is, I _C = {(V _fc + V _fd ) −V _be } / R ₁₁ ... R ₁₁ = R _e. The stop-time charging current is smaller than the driving-time charging current indicated by the equation. Therefore, the AC
The DC / DC converter 1 does not need to be cooled by the cooling unit 6, and the cooling unit 6 may be driven in synchronization with a driving instruction from the power supply control unit 4.

FIG. 5 shows a battery unit according to a third embodiment. In this example, unlike the battery units according to the first and second embodiments, an instruction-dependent constant current unit 83 is provided instead of the detection result-dependent constant current units 81 and 82. The instruction-dependent constant current unit 83
Has a transistor 83a and diodes 83d and 83e, and the diode 83d is short-opened by a transistor 83b, as shown in FIG. Further, the collector of the transistor 83c is connected to the base of the transistor 83b.
The constant current diode 83f is connected to the base of the transistor 83c.

The operation of this embodiment will be described. In this example,
DC / DC converters 21 and 2 from the power control unit 4
3 is instructed by the signal converter 9, the transistor 9a is turned on, and the electromagnet 5a of the switch 5 is turned on.
Is excited, the movable part 5b is moved, and the battery 3 is connected to the DC / DC converters 21 and 23 to prepare for the case where the AC power supply is interrupted. At this time, the constant voltage diode 83f of the instruction-dependent constant current unit 83 is in a cut-off state, and the transistor 83
c is also in the blocking state. Therefore, the charging current at the time of driving is determined by the voltage value obtained through the diodes 83d and 83e. That is, I _C = {(V _fd + V _fe ) −V _be } / R _g . Here, V _fd and V _fe are the diodes 83d and 83
e is the built-in voltage between the anode and the cathode, and R _g is the resistance value of the resistor 83 _g .

On the other hand, when there is an instruction from the power supply control unit 4 to stop the DC / DC converters 21 and 23, when the transistor 9a of the conversion unit 9 is turned off, the constant voltage diode 83f enters a breakdown region, A reverse current will flow through the diode 83f. Therefore, the base of the transistor 83c is in a high state, and the transistor 83b is in a conductive state. Therefore, if, as the voltage value V _ce between the collector and emitter of the transistor 83b becomes 1/3 of the internal voltage V _f1 between the cathode and the anode of the diode 83d, i.e., V _fd = 0.6V,
When V _ce is set to 0.2 V, the charging current at stop is smaller than the charging current at driving according to the equation. Therefore, when the DC / DC converter 1 is stopped, there is no need to drive the cooling unit 6 for cooling the AC / DC converter 1, and power is saved. As described above, in the present embodiment, as shown in FIG. 2, since a large number of battery units are provided, even if the decrease in the current value of each battery unit is small, the sum is N times, and the degree of power saving is large.

[0020]

As described above, according to the present invention, when a stop instruction is given to the DC driving device, a current smaller than the current value of the driving charging current supplied at the time of driving is obtained. A stop charging current having a value is supplied to the battery. Therefore, when the DC drive device is stopped, it is not necessary to drive the cooling unit for cooling the AC / DC converter, and the power consumption of the battery backup DC supply device can be saved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the principle of the present invention.

FIG. 2 is an overall block diagram according to an embodiment;

FIG. 3 is a circuit diagram showing a battery unit according to the first embodiment.

FIG. 4 is a circuit diagram showing a battery unit according to a second embodiment.

FIG. 5 is a circuit diagram showing a battery unit according to a third embodiment.

FIG. 6 is an overall block diagram according to a conventional example.

FIG. 7 is a circuit diagram showing a battery unit according to a conventional example.

[Explanation of symbols]

 10, 1 AC / DC converter 20, 2 DC drive device 30, 3 battery 4 Power supply control unit 50, 5 Switch unit 60, 70, 6, 7 Cooling unit 80, 81, 82, 83 Instruction dependent constant current unit 9 Signal conversion Department

Claims (4)

(57) [Claims] 1. An AC / D converter for converting an AC voltage into a DC voltage.
The C converter (10), a battery (30) for backing up a DC drive device (20) driven by a DC voltage in the event of an AC power failure, and an instruction to drive and stop the DC drive device (20) Switch unit (50) for connecting or disconnecting the battery (30) to or from the DC driving device (20)
A DC backup device that supplies DC to the DC drive device (20) and charges the battery (30) even when the DC drive device (20) is stopped; AC / DC when the driving instruction of 20) is given
When the cooling unit (60) that cools the converter (10) and the drive of the DC drive device (20) are instructed,
The charging current at the time of driving is supplied to the battery (30), and when there is an instruction to stop the DC driving device (20), the charging current at the time of stopping having a current value smaller than the charging current at the time of driving is supplied to the battery (30). And a command-dependent constant current section (80) for supplying the DC power to the battery. 2. The command-dependent constant current section (80) includes two types of constant current circuits connected in parallel, and a DC driving device (2).
0), the sum of the charging currents from the two circuits is used as the driving charging current for the battery (3).
0), and when there is an instruction to stop the DC driving device (20), the charging current from one of the circuits is supplied to the battery (30) as the stopping charging current. The battery backup DC supply device according to claim 1. 3. The control circuit according to claim 2, wherein the instruction-dependent constant current section (80) is a DC power supply.
A resistor having a variable resistance value is provided according to a drive instruction and a stop instruction of the driving device (20), and a drive charging current and a stop charging current are respectively set according to the drive instruction and the stop instruction. The battery backup DC supply device according to claim 1, wherein the DC power is supplied to a battery (30). 4. The command-dependent constant current section (80) includes a DC
Switching to a diode having a different built-in potential in accordance with a drive instruction and a stop instruction of the driving device (20), and in response to a drive instruction and a stop instruction, a driving charge current and a stop charge current are respectively changed to a battery ( The battery backup DC supply device according to claim 1, wherein the battery backup DC supply device is supplied.