JPH0223041A - Uninterruptible power source equipment - Google Patents

Abstract

PURPOSE:To stabilize charge operation and output voltage even when an over- discharged battery is employed by working over-discharge protective function through monitoring of battery voltage upon occurrence of power interruption. CONSTITUTION:Upon interruption of a commercial power source AC, a second relay RL2 is de-energized to open a contact RL2a and a relay RL1 is ON/OFF controlled through a transistor TR functionable corresponding to the voltage divided by resistors R1, R2. In other words, output voltage from a charger CHG goes to 0V upon occurrence of power interruption, but -48V output voltage from a battery BAT is fed through a contact RL1a to the output terminal side thus providing a power supply continuously to the system. When the output voltage Vout of the battery BAT is higher than the discharge limit voltage, i.e., -44V, the transistor TR functions continuously to sustain energization of the relay RL1 thus keeping the contact RL1a in closed state. By such arrangement, output from the battery BAT is fed continuously to the system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an improvement of an uninterruptible power supply used in a private branch exchange or the like.

(Prior art) Equipment that is required to operate even during a commercial power outage, such as a private branch exchange, has a storage battery in its system power supply, and usually generates the required DC from the commercial power supply. In addition to supplying the generated DC voltage to the system, a storage battery is charged with the generated DC voltage, and in the event of a power outage of the commercial power supply, power is supplied from the storage battery to ensure uninterrupted operation.

FIG. 3 is a circuit showing the configuration of a conventional uninterruptible power supply in a private branch exchange (hereinafter referred to as PBX).
CIIG is a charger and is a circuit that generates a system-required DC voltage from a commercial power supply AC, and since the target is a PBX here, it generates -54.6V. Sw is a commercial power input switch of this charger CHG. Further, BAT is a storage battery, and is connected between the output side terminals of this charger COG via a normally open contact RLla of a relay RLI. R
1 and R2 are resistors connected in series, and the charger CO
Connected between the output side terminals of G, the voltage between the terminals Vout −G
Partial pressure is applied to ND. RLI is a relay (excitation coil side)
, TR are PNP type transistors, and the base side of the transistor TR is connected to the resistor 1?1. Also, connect the emitter side to the ground side G of the charger CHG at the voltage dividing point by R2.
ND terminal, and the collector side is connected to the -54,8V side V out terminal of the charger CHG via the relay RLI. The V out and GND side terminals are connected to the system side and supply power to the system. In addition, the storage battery BAT here consists of 24 lead-acid batteries connected in series.
Let us take as an example a case in which 8V DC is to be obtained.

In such a configuration, when the commercial power supply AC is first applied to the charger CIIG by turning on the commercial power switch SW shown in FIG. 3, the charger CIIG receives -54.8 V DC, which is the storage battery floating charging voltage. generate. This DC output is output to the output terminal side and supplied to the system (
Time TI in FIG. 4). On the other hand, this output terminal side voltage is divided by resistors R1 and R2 and given as the base potential of the transistor TR, so that the output terminal voltage V out of the charger CIIG is the discharge limit voltage of the storage battery BAT - 44V.
Since the transistor TR is set to operate in the above manner, when the output terminal voltage V out of the charger CIIG becomes equal to or higher than the discharge limit voltage -44V, the transistor TR
works and relays! ? L1 is energized. That is, 5
In the case of Figure 54, when Vout becomes 144V or higher, is relay 1? LL is energized. As a result, the normally open contact RLLa of the relay RLI is closed (time T2), which is 12 o'clock due to the effect of the operation delay time), and the normally closed contact R
The output of the charger CIIG is applied through Lla, and the storage battery BAT is charged.

Here, it is assumed that the commercial 'Q[AC] has a power outage at time T3 in FIG. Then, the output of the charger CIIG itself becomes O.
v, but the output voltage of storage battery BAT -48V is the contact R
Power is supplied to the output terminal side through Lla, and power is supplied to the system without change. Also, at this time, V out
Since is equal to or higher than the discharge limit voltage -44V, the transistor TR continues to operate, and therefore the relay RLI also remains energized.

Therefore, since the contact RLla is maintained in the closed state, the relay RLI remains energized from now on.

As a result, the output of the storage battery BAT becomes the contact point t? L1
will continue to be supplied to the system via a.

However, the discharge of the storage battery BAT progresses, and eventually T
At point 4, the output voltage of storage battery BAT is the discharge limit voltage -4
When the voltage drops below 4V, transistor TR turns off, which deenergizes relay RLI, so its contact RL1a
is turned off, storage battery BAT is disconnected from the output terminal, and over-discharge of storage battery BAT is prevented.

Incidentally, the relationship between the output current of the charger CHG and the gravitational voltage has a drooping characteristic as shown in FIG. Note that here, an example is shown in which the maximum output current of this charger CHG is LOA.

Therefore, when a storage battery BAT is connected to this charger CI (G), if this storage battery DAT is sufficiently charged, the battery voltage will be -54.6V (point A in Figure 5), which is the floating charging voltage. However, if the storage battery BAT is discharged to some extent, even if a current of 10A is applied from the charger CHG, the battery voltage of the storage battery BAT is a floating charging voltage -54
．． Since the voltage does not rise to 8 V, the voltage falls below the floating charging voltage as shown at point B and point 0 in FIG. 5, and in extreme cases, it may fall below the discharge limit voltage of -44 V. If the storage battery is discharged to some extent and the charger is connected, it will only rise to point B in Figure 5, then the DC output voltage Vout with respect to the commercial power AC input will be as VoutB in Figure 6. become.

That is, when the input of the commercial power supply AC is applied to the charger CHG at time T1 in FIG. 6, the DC output voltage v o
ut becomes -54.6V, which activates the transistor TR and energizes the relay RLI, which closes the contact RLla at time 12 in Fig. 6 and connects the storage battery BAT to the output terminal. Therefore, vout will decrease to that battery voltage. Thereafter, as charging of the storage battery DAT progresses, the voltage VOut at the output terminal increases and eventually becomes constant at -54.6 V, which is the floating charging voltage.

On the other hand, when the storage battery 13AT is over-discharged, the battery voltage is below the discharge limit voltage -44V, and in this case, the DC output voltage V out with respect to the commercial power supply AC is Vo in FIG.
The change will be similar to utC. That is, when commercial power supply AC is applied to charger C) IC at time T1 in FIG. Since the RLI is energized, the contact RLla is closed at time 12 in FIG. 6, the storage battery BAT is connected to the output terminal, and Vout drops to the battery voltage (0 point voltage). Since the voltage at this zero point is different from the voltage at the above-mentioned point B and is lower than the discharge limit voltage -44V, the transistor TR is turned off, the relay RLI is deenergized, and the contact RL1a is opened. However, due to this, storage battery DA
When T is disconnected, the output from charger CIIG is -5
To recover to 4.8 V, the transistor TJ? operates, relay RLI is energized, and contact RL in Figure 6 is activated.
la is closed, storage battery BAT is connected to the output terminal, and V out drops to the battery voltage. Since this voltage is less than the discharge limit voltage -44V, the transistor TR
is turned off, relay RLL is deenergized and contact 1? Ll
a is opened. As a result, the storage battery BAT is disconnected and the output from the charger CIIG is -54.8 V.
to recover. Then, the operation of TR being turned off again, changing to the voltage of the storage battery, turning off TR, and changing to the output of the charger, is repeated at a cycle of ΔT. After that, when the charging of the storage battery DAT progresses and exceeds the overdischarge voltage,
Such repeated ON/OFF operation of relay RLI is eliminated, contact RLla continues to be closed, and storage battery DAT
As the charging progresses, the voltage v out at the output terminal increases and eventually becomes constant at -54.8 V, which is the floating charging voltage.

(Problem to be solved by the invention) In this way, the uninterruptible power supply used in PBX generates a DC output of a predetermined voltage from the commercial power supply, supplies it to the system, and connects it to the storage battery via a relay. The relay is turned on/off by a control means that monitors the voltage between the output terminals of the uninterruptible power supply and turns it on when it is above a predetermined discharge limit voltage, and turns it off when it is below the discharge limit voltage. When there is generated voltage output from the commercial power source and the battery voltage of the storage battery is sufficient, connect the storage battery to the output terminal of the uninterruptible power supply, and when the generated voltage output from the commercial power source decreases or there is a power outage, the storage battery of battery voltage to the system so that the PBX continues to operate normally. However, if the storage battery is exhausted during a power outage and the battery voltage drops below the discharge limit voltage, it will have an adverse effect on the storage battery, so in order to protect the storage battery, when the battery voltage falls below the discharge limit voltage, the relay is turned off and the storage battery is disconnected. I have to.

However, the battery voltage is monitored using the voltage between the output terminals of the uninterruptible power supply, and there is a slight delay in the relay on/off control operation based on the monitoring results, so the battery voltage may be low when the storage battery is not fully charged. is lower than the discharge limit voltage, when the commercial power is turned on after installing the storage battery,
The battery is disconnected by the relay in the OFF state,
Therefore, the relay turns on by detecting the generated voltage from the commercial power supply and starts charging the storage battery, so the voltage between the uninterruptible power supply output terminals becomes lower than the discharge limit voltage due to this charging, and the relay turns off. The generated voltage from the commercial power supply is detected again and the relay is turned on, and the storage battery begins to be charged. Due to this charging, the voltage between the uninterruptible power supply output terminals becomes lower than the discharge limit voltage, and therefore the relay is turned off. The generated voltage from the commercial power supply is detected again and the relay is turned on, and so on, and so on, and the relay repeats on/off at a predetermined period. Therefore, there is a problem of shortening the life of the relay, and the system that is supplied with such pulsed unstable voltage becomes unstable until the voltage stabilizes.
It may also cause abnormal operation or failure.

SUMMARY OF THE INVENTION An object of the present invention is to protect a relay for controlling connection of a storage battery by preventing it from operating intermittently over a long period of time in short cycles even when a discharged storage battery is used. An object of the present invention is to provide an uninterruptible power supply capable of stabilizing the voltage supplied to a system by preventing pulsed voltage output.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention is configured as follows. That is, it generates a DC output of a predetermined voltage from a commercial power supply and supplies it to the system, and connects it to the storage battery via a switch means to charge the storage battery and supply the battery output to the system side. An uninterruptible power source that controls charging and discharging of the storage battery by a control means that monitors the voltage and controls the switch means so that the storage battery is connected when the voltage is above a predetermined discharge limit voltage and disconnected when it is below the discharge limit voltage. The device is configured to include forced holding means that operates when the commercial power is input to control the switch means and forcibly connect the DC output to the storage battery.

(Function) In this configuration, the required DC output within the system is generated and supplied from the commercial power supply, but when the generated voltage output decreases or there is a power outage, the battery voltage of the storage battery is supplied to the system. ensure system operation. Therefore,
The system supply voltage is monitored, and when the voltage exceeds a predetermined discharge limit voltage, the switching means is closed, and the generated voltage output maintains the charging of the storage battery and the application of battery output to the system supply line, so that the storage battery does not become over-discharged. In this device, when commercial power is applied, the switch means is forcibly kept in the closed circuit state by the forced holding means to enable charging/discharging. Therefore, even if the voltage of the storage battery is lower than the discharge limit voltage, the switch means is continuously closed, and the voltage supplied to the system does not have small fluctuations. When the commercial power supply is interrupted, the forced circuit closing control of the switch means is canceled, and control of the switch means and system power supply based on the battery voltage of the storage battery are started. If the storage battery is exhausted and becomes over-discharged, it will have an adverse effect on the storage battery, so in order to protect the storage battery, the control means opens the switch means to disconnect the storage battery when the battery voltage becomes lower than the discharge limit voltage. In this way, the storage battery is forcibly connected and charged while commercial power is applied, and when a power outage occurs, this is released and the overdischarge protection function is activated by monitoring the storage battery's battery voltage. ,
Even when using an over-discharged storage battery, stable charging operation and output voltage stabilization can be achieved, and even when a relay is used as a switching means, the relay can prevent intermittent operation over a long period of time in short cycles. It is possible to provide an uninterruptible power supply device that protects the system and stabilizes the voltage supplied to the system by preventing pulsed voltage output from occurring.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. Figure 1 is a circuit diagram showing the configuration of this device, and in the figure CII
G is a charger and is a circuit that generates the DC power required for the system from the commercial AC power supply, and since the target is a PBX here, it generates -54.6V.

SW is a commercial power input switch for this charger CIIG. Further, BAT is a storage battery, and is connected between the output side terminals of this charger CIIG via a normally closed contact RLla of a relay RLI. R1 and R2 are resistors connected in series, which are connected between the output terminals of the charger CHG to divide the inter-terminal voltage Vout - GND. RLI is a relay (excitation coil side), TR is a PNP type transistor, and the base side of the transistor TR is connected to the voltage dividing point by the resistors R1 and R2, and the emitter side is connected to the ground side GND terminal of the charger CIIG. Then, connect the collector side to -54,6V of the charger COG via relay RLI.
Connect to the side v out terminal. The V out and GND side terminals are connected to the system side and supply power to the system. Note that the storage battery DAT is exemplified here by 24 lead-acid batteries connected in series to obtain a DC voltage of -48V.

The configuration up to this point is the same as the conventional example explained in FIG. In this device, in addition to the conventional configuration, a second relay 1? L2 (excitation coil)
The normally open contact RL2a of this second relay RL2 is connected between the emitter and collector of the transistor TR, so that when the commercial power supply AC is normal, the transistor TI? The control of the relay RLI by the second relay RL2 is stopped, and the normally open contact RL2a of the second relay RL2 is used to forcibly energize the relay 12Ll instead.

In such a configuration, first, by turning on the commercial power switch Sw shown in FIG. 3, the second relay RL2 is excited, and this second relay 1? Normally open contact RL2a of L2
Close. Then, when the commercial power supply AC is applied to the charger CHG by turning on the commercial power switch SW, the charger C
Since HG generates DC of -54.6V, which is the storage battery floating charging voltage, this DC output is output to the output terminal side,
while being supplied to the system and relay RLI;
The relay RLI is energized. As a result, relay 1? L
The normally closed contact RLla of the battery BAT is closed, and the output of the charger ClIC is applied through the normally closed contact RL1a.
will be charged. At this time, if storage battery BA
If T is in an overdischarge state, the output voltage v out of the uninterruptible power supply becomes below the discharge limit voltage due to charging of the storage battery BAT, but relay RLI is energized because of relay RL2 of jl$2. Since the normally closed contact RLla continues to remain closed, the storage battery BAT continues to be charged as shown in FIG. 2(b). As charging progresses, the output voltage Vout of the uninterruptible power supply slowly rises to -54.8 which is the floating charging voltage.
Once it reaches V, it is kept at this voltage.

Therefore, even if the storage battery BAT is in an over-discharge state,
Unlike in the past, the relay RLI does not repeat intermittent cycles in short cycles, and the output voltage Vo of the uninterruptible power supply
ut also rises slowly and does not undergo pulse-like changes.

Here, assume that the commercial power supply AC has a power outage. Then, the second
relay RL2 is deenergized, so the second relay RL2
Contact RL2a opens, and relay RLI is activated by transistor TR, which operates according to the voltage divided by resistors R1 and R2.
will be controlled on/off.

In other words, due to a power outage, the output of the charger C) IG itself becomes Ov.
However, the output voltage of storage battery BAT is -48V at contact RL.
It is supplied to the output terminal side through la, and power is supplied to the system without change. At this time, if v out is equal to or higher than the discharge limit voltage of the storage battery BAT -44V, the transistor TR continues to operate, and therefore the relay RLI
remains energized.

Therefore, since the contact RL1a is maintained in the closed state, the relay RLI remains energized from now on.

As a result, the output of the storage battery BAT is changed to the contact RL1a.
will continue to be supplied to the system via

However, the discharge of storage battery BAT progresses, and eventually storage battery BA
When the output voltage of T is below the discharge limit voltage -44V, transistor TR is turned off, thereby relay 1? Since L1 is deenergized, its contact RL1a is turned off, and storage battery BAT is disconnected from the output terminal, thereby preventing overdischarge of storage battery BAT.

In this way, this device generates DC output at legal voltage from a commercial power source and supplies it to the system, and also connects to the storage battery via a relay to charge the storage battery and supply battery output to the system. Further, in the uninterruptible power supply, the relay is turned on/off by a control means that monitors the system supply voltage and turns on when it is above a predetermined discharge limit voltage and turns off when it is below the discharge limit voltage. A forced holding circuit that operates when commercial power is input to form a forced energizing circuit for the relay is provided to forcibly turn on the relay.

Then, the system generates and supplies the required DC output from the commercial power supply, and when the generated voltage output decreases or there is a power outage, the battery voltage from the storage battery is supplied to the system to ensure system operation. , monitors the system supply voltage, turns on the relay when it exceeds a predetermined discharge limit voltage, and maintains a state in which the storage battery is charged by the generated voltage output and battery output is applied to the system supply line, so that the storage battery does not become over-discharged. Backup against power outage within range,
In this device, a forced holding circuit consisting of a second relay that operates when commercial power is applied forces the relay for connecting the storage battery to the ON state, making it possible to charge/discharge, and thereby the storage battery reaches the discharge limit. Even if the voltage is lower than the voltage, the relay for connecting the storage battery is kept on continuously to prevent the relay from turning on and off frequently, and to prevent small fluctuations in the voltage supplied to the system. be. When the commercial power supply is out of power, the forced on control of the relay for connecting the storage battery is released, and control of the relay for connecting the storage battery and system power supply are performed based on the battery voltage of the storage battery, so that the storage battery is exhausted. In order to protect the storage battery, the control means turns off the relay for connecting the storage battery and disconnects the storage battery when the battery voltage becomes lower than the discharge limit voltage. As such, the storage battery is forcibly interlocked to the charging state while commercial power is applied, and when a power outage occurs, the interlock is released and the overdischarge protection function by monitoring the storage battery voltage is activated. Therefore, even when using an over-discharged storage battery, stable charging operation and output voltage stabilization can be achieved, and the relay can be protected by preventing intermittent operation over a long period of time in short cycles. It becomes possible to stabilize the voltage supplied to the system by preventing pulsed voltage output.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, and can be implemented with appropriate modifications within the scope of the gist thereof, and the relay for connecting the storage battery may be a semiconductor switch element such as a transistor. It can also be replaced.

〔Effect of the invention〕

As described in detail above, according to the present invention, even when an over-discharged storage battery is used, stable charging operation and stabilization of the output voltage can be achieved. Therefore, it is possible to provide an uninterruptible power supply device having such characteristics that it can supply a suitable voltage and eliminate the risk of abnormal or unstable operation.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2 is a time chart showing its action, Fig. 3 is a circuit diagram showing the configuration of a conventional device, and Figs. 4 to 6 show its action. It is a figure for explaining. AC...Commercial power supply, CHG...Charger, RL11?
L2-...Relay, RLla, RL2a-"normally open contact, R1, R2-...Resistor, TR...Transistor, B
AT...storage battery, Sv...switch. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] It generates a DC output of a predetermined voltage from a commercial power supply and supplies it to the system, and connects it to the storage battery through a switch means to charge the storage battery and supply the battery output to the system side, and also adjusts the system supply voltage. In an uninterruptible power supply device, the charging and discharging of the storage battery is controlled by a control means that monitors and controls the switch means to connect the storage battery when the voltage exceeds a predetermined discharge limit voltage, and disconnect it when the voltage falls below the discharge limit voltage. . An uninterruptible power supply device comprising: forced holding means that operates when the commercial power is input to control the switch means and forcibly connect the DC output to the storage battery.