JP3317599B2 - Uninterruptible power system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an uninterruptible power supply, and more particularly to an uninterruptible power supply having means for protecting a storage battery from function deterioration or loss due to self-discharge of the storage battery when the charging function of the storage battery is abnormal. .

[0002]

2. Description of the Related Art Uninterruptible power supplies, which use a storage battery as a power source to supply stable AC power even in the event of a power failure or momentary voltage drop, have been widely used as power supplies for important load systems such as computers. It has become to.

FIG. 3 is a configuration diagram showing an example of a conventional uninterruptible power supply. In the figure, 1 is an AC input power supply, 2
Is a rectifier having a function of converting AC supplied from the AC input power supply 1 into DC and charging the storage battery 3; a storage battery 3 is a DC power supply serving as a backup energy source when the AC input power supply 1 fails; DC output or storage battery 3
Inverter that converts the DC output of the inverter to stable AC power, 5
A load is supplied with AC power from the inverter 4.

The storage battery 3 is normally charged by the rectifier 2 at a constant voltage equivalent to the floating voltage, and maintains its function as a storage battery in preparation for an AC input power failure while supplementing the self-discharge of the storage battery itself.

[0005]

In the conventional uninterruptible power supply as shown in FIG. 3, when the voltage corresponding to the floating voltage of the storage battery 3 cannot be maintained due to the abnormal control of the rectifier 2, the function of the storage battery 3 is affected. . For example, if the charging voltage by the rectifier 2 is maintained for about 10% and maintained for a long time, the specific gravity of the electrolytic solution of the storage battery 3 decreases, and the deterioration of the electrode plate progresses, so that the function as the storage battery may be reduced or lost. There is. In particular, lead batteries have such a tendency to be self-discharged, so that even if they are recharged, they may not be able to recover at worst.

Incidentally, as the output of the uninterruptible power supply, a stable AC output can be supplied by the inverter 4 even if the DC output of the rectifier 2 slightly decreases as long as the AC input is normal. The effect of the loss of the function of the storage battery 3 starts only when the AC input is interrupted or the instantaneous voltage drops.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has an uninterruptible power supply capable of protecting a storage battery from function deterioration or loss caused by abnormality in the storage battery charging function. The purpose is to provide.

[0008]

In order to achieve the above object, a first aspect of the present invention provides a rectifier for converting AC supplied from an AC input power supply into DC, and a rectifier or another rectifier when the AC input power supply is normal. A storage battery charged by a charger, DC is supplied from the rectifier when the AC input power supply is normal, and DC is supplied from the storage battery when the AC input power supply fails or the voltage drops, and an inverter for converting DC to AC. And a comparator that generates an output signal when the voltage of the storage battery falls below a predetermined value, and the output of the comparator corresponds to the self-discharge characteristics and the deterioration characteristics of the storage battery. A timer that detects an abnormal charging function when the specified time limit is exceeded to protect the storage battery from function deterioration or loss due to charging function abnormality. A. . According to another aspect of the present invention, there is provided a rectifier for converting AC supplied from an AC input power supply into DC power, and a storage battery charged by the rectifier or another charger when the AC input power supply is normal. An uninterruptible power supply comprising an inverter which is supplied with DC from the rectifier when the AC input power supply is normal, and is supplied with DC from the storage battery when the AC input power supply fails or the voltage drops, and converts DC into AC. In the device,
Deviation detecting means for detecting a deviation between a predetermined reference voltage corresponding to a self-discharge characteristic and a deterioration characteristic of the storage battery and the storage battery voltage; integration means for integrating a deviation output of the deviation detection means with time; A comparator is provided for detecting a charging function abnormality when the output reaches a level corresponding to the storage battery recoverable limit, thereby protecting the storage battery from function deterioration or loss due to the charging function abnormality. .

[0009]

According to the first aspect of the present invention, when the charging voltage of the storage battery drops for some reason, the comparator detects the drop in the charging voltage, and if the charging voltage of the storage battery drops, the comparator detects the drop. If it is not transient and continues for a long time, the timer issues an alarm when the comparator voltage drop detection output continues for a predetermined time set by the timer. Thereby, if an abnormality alarm is received and the cause of the decrease in the charging voltage of the storage battery is repaired or the emergency treatment for regular charging of the storage battery is performed, the deterioration or loss of the function of the storage battery can be prevented.

According to the second aspect of the invention, the voltage deviation detected by the deviation detecting means is integrated over time by an integrator, and the time integrated value of the voltage deviation corresponds to the self-discharge characteristic and the deterioration characteristic of the storage battery. If the set value is reached, compare
Alarms. Thereby, if an abnormality alarm is received and the cause of the decrease in the charging voltage of the storage battery is repaired or the emergency treatment for regular charging of the storage battery is performed, the deterioration or loss of the function of the storage battery can be prevented.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the block diagram of FIG. In FIG. 1, the same parts as those in FIG. 3 are denoted by the same reference numerals, and the description thereof will be omitted. Here, different points will be described. In the figure, reference numeral 11 denotes a comparator for detecting a voltage drop of the storage battery 3, reference numeral 12 denotes a setter for setting a detection reference for detecting a voltage drop by the comparator 11, and reference numeral 13 denotes a time when the output of the comparator 11 is detected for a predetermined time. It is a timer that issues an alarm output when it is continued.

The set value of the detection criterion setting unit 12 is determined from the deterioration characteristics of the storage battery 3 due to self-discharge. For example,
In the case of a lead-acid battery, the detection reference value is reduced by several percent (for example, reduced by 5%) because if the state of being lowered by 10% from the floating voltage continues for several months, the function may be significantly reduced or the recovery may not be possible.
Must be set to

The time setting by the timer 13 must be coordinated with the recovery charge characteristic after the storage battery 3 has been discharged due to a normal AC input power failure (as long as the function of the rectifier 2 is normal, the recovery charge is not required). Even if the voltage level is lower than the detection standard, an alarm should not be issued carelessly.) For example, if it is expected that recovery charging will take up to 24 hours, the time limit setting of the timer 13 is set to a longer time.

Next, the operation of the first embodiment of the present invention having the structure shown in FIG. 1 will be described. For example, when the charging voltage of the storage battery 3 decreases due to a component failure inside the rectifier 2 or the like, the comparator 11 detects the voltage decrease. Rectifier 2
If the abnormality of the battery is not transient and the voltage drop of the storage battery 3 continues for a long time, the output of the voltage drop detection of the comparator 11 continues for a predetermined time set by the timer 13 and the timer 13 is reset. Issues an abnormal alarm.

Thus, upon receiving an abnormality alarm, the rectifier 2
The repair or the emergency treatment for the regular charging of the storage battery 3 can prevent the deterioration or loss of the function of the storage battery 3.

As described above, in the present embodiment, by detecting the charging function abnormality of the rectifier 2 with the voltage and the time period corresponding to the self-discharge characteristic and the deterioration characteristic of the storage battery 3, the deterioration or loss of the function of the storage battery 3 can be prevented. Can be prevented.

Next, an uninterruptible power supply according to a second aspect of the present invention will be described with reference to the block diagram of FIG. In the embodiment shown in FIG. 2, the deviation detector 21 detects a voltage deviation between the storage battery voltage and the detection reference value set by the setting unit 22, and integrates the detected voltage deviation with time by an integrator 23. When the time integration value of the time exceeds the value set by the setter 25, the comparator 24 issues an alarm of the charging function abnormality.

Also in this case, the set values of the setting devices 22 and 25 are set in accordance with the self-discharge characteristics and the deterioration characteristics of the storage battery 3, and are detected by voltage integration.
More accurate detection is possible.

[0019]

As described above, according to the first and second aspects of the present invention, it is possible to protect the storage battery from being deteriorated or lost in function due to an abnormality in the storage battery charging function. An uninterruptible power supply can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of an uninterruptible power supply according to the invention of claim 1;

FIG. 2 is a configuration diagram showing one embodiment of an uninterruptible power supply according to the invention of claim 2;

FIG. 3 is a configuration diagram of a conventional uninterruptible power supply.

[Explanation of symbols]

1 ... AC input power supply 2 ...
Rectifier 3 ... storage battery 4 ...
Inverter 5… Load 11…
Comparator 12… Reference value setting device 13…
Timer 21… Deviation detector 22…
Reference value setting device 23… Integrator 24…
Comparator 25… Reference value setting device

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02J 9/06 G01R 31/36 H02H 7/18

Claims (2)

(57) [Claims] A rectifier for converting alternating current supplied from an alternating current input power to direct current, a storage battery charged by the rectifier or another charger when the alternating current input power is normal,
An uninterruptible power supply comprising an inverter which is supplied with DC from the rectifier when the AC input power supply is normal, and is supplied with DC from the storage battery when the AC input power supply fails or the voltage drops, and converts DC into AC. A comparator for generating an output signal when the voltage of the storage battery falls below a predetermined value; and a charging function when the output of the comparator exceeds a time period corresponding to the self-discharge characteristics and the deterioration characteristics of the storage battery. An uninterruptible power supply device comprising a timer for detecting an abnormality to protect a storage battery from function deterioration or loss due to a charging function abnormality. 2. A rectifier for converting AC supplied from an AC input power supply to DC, a storage battery charged by the rectifier or another charger when the AC input power supply is normal.
An uninterruptible power supply comprising an inverter which is supplied with DC from the rectifier when the AC input power supply is normal, and is supplied with DC from the storage battery when the AC input power supply fails or the voltage drops, and converts DC into AC. A deviation detecting means for detecting a deviation between a predetermined reference voltage corresponding to a self-discharge characteristic and a deterioration characteristic of the storage battery and the storage battery voltage,
Integrating means for integrating the deviation output of the deviation detecting means with time;
A comparator is provided for detecting a charging function abnormality when the output of the integrating means reaches a level corresponding to the storage battery recoverable limit, thereby protecting the storage battery from function deterioration or loss due to the charging function abnormality. Uninterruptible power supply.