JPH03183327A - Uninterruptible power source - Google Patents

Abstract

PURPOSE:To simply detect malfunction of a charging state at the time of charging a battery by connecting the battery to a dummy-load from a charging state to discharge it, and monitoring a voltage at the time of discharging to detect whether its voltage drop is suitable or not. CONSTITUTION:When a commercial power source has no malfunction, a battery 22 is periodically inspected. That is, a microprocessor 26 controls to periodically switch a changeover switch 28, and to periodically discharge a battery 22 to a dummy-load 27 for a predetermined time. A discharging voltage at this time is checked by a comparator 29, which informs externally by an alarm generator 30 if it is lower than a discrimination voltage VREF. Thus, a malfunction due to a life to be difficult to be detected, a malfunction due to overdischarge when stored for maintenance can be detected before a power interruption which occurs irregularly.

Description

[Detailed Description of the Invention] [Summary] This invention relates to an uninterruptible power supply equipped with means for detecting the state of charge of a pantry, and aims to easily detect a defective state of charge when charging a battery. An uninterruptible power supply having a charger for charging a battery, comprising a pseudo load, a switching means for cutting off a charging path from the charger to the battery and connecting a discharge path of the battery to the pseudo load, and the battery. discharge voltage monitoring means for detecting whether the voltage during discharge to the pseudo load is appropriate.

[Industrial Field of Application] The present invention relates to an uninterruptible power supply that supplies a specified alternating current output for a certain period of time even if the AC input is interrupted, and particularly relates to an uninterruptible power supply that includes means for detecting the state of charge of a battery. .

Generally, devices such as computers that have a large impact on society are equipped with an uninterruptible power supply having a battery outside the device as a countermeasure against power outages. The uninterruptible power supply normally supplies commercial power to a load device (such as a computer) and charges an internal battery, and when a power outage occurs, it supplies power from the internal battery for backup. However, if there is a problem with the battery in the uninterruptible power supply, charging will not be performed properly and the device will not be able to be backed up even if a power outage occurs. Therefore, it is important to accurately monitor the state of charge of the battery and detect failures in advance so as not to impair the intended backup function.

[Prior art] Figure 4 shows an uninterruptible power supply (hereinafter referred to as UPS)
This is an example. In the USP shown in the figure, if there is no abnormality in the commercial power supply, the commercial power supply is directly supplied to a load device such as a computer, and at the same time is supplied to the charger 42 via the transformer 4, where it is converted to DC. The battery 43 is charged.

In the event of a power failure in the commercial power source, the DC power generated by the discharge of the battery 43 is converted into AC power by the inverter 44, and is supplied to the load device as AC power via the transformer 41.

Conventionally, the charging state of the battery 43 configured as described above has been detected by methods such as (1) monitoring the battery charging voltage, and (2) integrating the charging current.

That is, in (1) monitoring the battery charging voltage, since the charging voltage to the battery changes as shown in Figure 5 depending on the charging state, the charging state is detected by monitoring this voltage change. It is something. Also,
(2) Integration of charging current attempts to detect the state of charge by integrating the current flowing from the charger to the battery over time and calculating the amount of charged charge.

[Problems to be Solved by the Invention] However, in the method (1) of monitoring the battery charging voltage, the change in voltage is very small and the variation is large, so it is difficult to detect the state of charge of the battery based on this. had become difficult. Furthermore, even if the charging voltage is monitored using this method, it is not possible to detect a defective state in which the inside of the battery is in a high impedance state due to overdischarge, etc., which poses a problem from the viewpoint of reliability. Furthermore, the method (2) of integrating the charging current requires a large-scale circuit to accurately obtain the time integral of the current, which poses a problem in terms of cost.

The present invention was created in view of these problems, and
It is an object of the present invention to provide an uninterruptible power supply device that can easily detect a defective state of charge when charging a battery.

[Means for Solving the Problem] The means in the present invention for achieving the above object are as follows:
As shown in the diagram explaining the principle of the present invention, in an uninterruptible power supply device having a battery 1 and a charger 2 for charging the pantry 1, a pseudo load 3 and a charger for charging the battery 1 from the charger 2 are provided. a switching means 4 for connecting the discharge path of the battery l to the pseudo load 3 by cutting off the path; and a discharge voltage monitoring means 5 for detecting whether the voltage at the time of discharging the battery 1 to the pseudo load 3 is appropriate. According to an uninterruptible power supply device characterized by comprising:

[Operation] As shown in FIG. 2, the present invention attempts to detect a battery failure by utilizing the fact that a voltage drop proportional to the internal impedance appears when the battery is discharged.

That is, the battery 1 is discharged from the charged state by the charger 2 by being connected to the pseudo load 3 by the switching means 4,
The voltage during this discharge is monitored by a discharge voltage monitoring means,
Detects whether the voltage drop is appropriate. Therefore, when the battery becomes defective due to end-of-life or over-discharge, the internal impedance increases and the voltage drop increases, making it possible to detect the defective state. If the switching means is controlled to switch periodically, the battery can be automatically inspected while being continuously charged.

[Example] Examples of the present invention will be described in detail below.

FIG. 3 is a schematic configuration diagram of an uninterruptible power supply according to an embodiment of the present invention. In the figure, 20 is AC wiring connected to a commercial power source and a load device such as a computer, 21 is a transformer connected to the AC wiring 20, and 22 is a battery 2.
Reference numeral 3 denotes a charger that converts human-powered AC into DC to charge the battery 22 via the transformer 21, 24 an inverter that converts DC to AC, and 25 an AC connected to the commercial power supply side to the connection point of the transformer 21. A bidirectional three-terminal thyristor is installed in the wiring 20, and 26 is a microprocessor (MPU) that controls switching elements in the device.
Reference numeral 7 denotes a pseudo load that serves as a load for discharging the battery 22 during the test; 28 indicates a changeover switch that cuts off the charging path from the charger 23 to the battery 22 and switches the discharge path of the battery 22 to the pseudo load 27 under the control of the MPU 26; 29;
is a comparator which is a discharge voltage monitoring means, which inputs the discharge voltage of the battery 22 and the judgment voltage v ltF, compares the two, and outputs a signal to that effect when the discharge voltage becomes lower than the judgment voltage V ltF. Output.

Reference numeral 30 denotes an alarm generator as an abnormality notification means, which emits a warning buzzer and a warning light to the outside based on the output signal of the comparator 29. A capacitor 31 is provided to supply power in place of the battery 22 when a power outage occurs in the commercial power supply while the battery 22 is being discharged to the pseudo load 27 .

In the uninterruptible power supply having the above configuration, when there is no abnormality in the commercial power supply, the bidirectional three-terminal thyristor 25 is turned on, and the commercial power supply is supplied as is to the load device. At the same time, the charger 23 is activated and the transformer 2
The battery 22 is charged by converting alternating current supplied from a commercial power supply via the AC power source 1 . When a commercial power outage is detected by a detector (not shown), the MPU
26 connects the charger 23 and the bidirectional 3-terminal thyristor 2
5 is turned off and inverter 24 is activated. As a result, the battery 22 changes from the charging state to the discharging state, and the discharged DC output is converted to AC by the inverter 24, and an AC output equivalent to that of the commercial power supply is output to the AC wiring 20 via the transformer 21, and the commercial power supply The power source is supplied to the load device as an alternative power source.

In the uninterruptible power supply in the above embodiment, the battery 22 is periodically inspected when there is no abnormality in the commercial power supply. That is, the MPU 26 periodically controls the changeover switch 28 to switch the battery 22.
A discharge for a certain period of time is periodically applied to the pseudo load 27. Then, the discharge voltage at that time is checked by the comparator 29, and if the voltage is lower than the determination voltage VREF, the alarm generator 30 notifies the outside. This determination voltage V REF is set lower than the discharge voltage of a good battery, and is set to a value that allows detection of a low discharge voltage of a defective battery whose internal impedance has increased due to overdischarge or life.

In this way, the uninterruptible power supply of this embodiment is designed to automatically test batteries, which are rarely used and are constantly charged, with a relatively simple configuration. Therefore, it is possible to detect defects due to lifespan, which have been difficult to detect, or defects due to over-discharge when stored for maintenance, before power outages occur irregularly.

In the above embodiment, the MPU 26 is used as a switching means to periodically switch the switch, but the present invention is not limited to this. For example, the switch may be manually switched and checked.

Further, although the discharge voltage monitoring means is configured to make a determination using one determination voltage, it may be configured to set a plurality of determination voltages so that the state of charge can be checked in multiple stages.

[Effects of the Invention] As explained above, according to the present invention, a battery that is continuously charged can be inspected in that state with a relatively simple configuration, and the lifespan that has been difficult to be detected can be improved. Since it is possible to detect in advance defects caused by over-discharge during storage for maintenance, etc., it is possible to provide an uninterruptible power supply that can be reliably backed up in the event of a power outage.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the principle of the present invention, Fig. 2 is an explanatory diagram of discharge voltage, Fig. 3 is a block diagram of an embodiment of the present invention, Fig. 4 is a block diagram of an example of an uninterruptible power supply, FIG. 5 is an explanatory diagram of charging voltage. 1.22.43... Battery 2.23.42... Charger, 3.27... Pseudo load, 4... Switching means, 5... Discharge voltage monitoring means, 20... AC Wiring, 21.41...Transformer, 24.44...Inverter, 25...Bidirectional 3@Children's Risk, 26...Microprocessor (MPU) 28...Selector switch, 29...Comparator , 30...Alarm generator. Figure 1 Figure 2 Figure 4 Figure 5

Claims (1)

[Claims] An uninterruptible power supply having a battery (1) and a charger (2) for charging the battery (1), comprising: a pseudo load (3); The charging path to the battery (1) is cut off and the discharging path of the battery (1) is changed to the pseudo load (1).
switching means (4) connected to the battery (3); and discharge voltage monitoring means (4) for detecting whether the voltage at the time of discharging the battery (1) to the pseudo load (3) is appropriate.
5) An uninterruptible power supply device comprising: