JPH06105483A - Ac uninterruptible power source - Google Patents

Abstract

PURPOSE:To provide a power source having functions for safely detecting and judging the end of the life of a storage battery or the unconnection of the battery with a low cost without providing a special discharge resistor for determining the life of the battery. CONSTITUTION:An Ac uninterruptible power source has functions for discharging a storage battery 40 with predetermined power by sequentially starting a charger 30, an inverter 20 and an AC/DC converter 10 in this order, estimating the internal resistance of the battery 40 based on the voltage before the discharge of the battery 40 and the voltage or the voltage drop after predetermined time of discharging, simply detecting and judging the end of the life of the battery 40 and externally reporting the result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of an AC uninterruptible power supply system which continuously supplies power to a load device by an inverter using a storage battery as a power supply when the voltage of a regular power supply drops or a power failure occurs.

[0002]

2. Description of the Related Art A conventional example of an AC uninterruptible power supply device is shown in FIG. In the figure, 1 is a commercial AC power supply, 2 is an AC output, 3 is a direct transmission circuit, 10 is an AC / DC converter, 2
Reference numeral 0 is an inverter, 30 is a charger, 40 is a storage battery, 41 is a storage battery discharge switch, 42 is a storage battery discharge resistance, 43 is a storage battery life determination circuit, and 44 is a start switch for the storage battery life determination circuit.

In such a conventional apparatus, as a normal starting sequence, the commercial AC power source 1 first supplies power to the AC output 2 through the direct feed circuit 3 and the switch 60. And A
After activating the C / DC converter 10 and the charger 30 and confirming that the DC output voltage has risen normally,
The inverter 20 is started. Then, when the inverter and the commercial power supply are in a synchronous state, the switching device 60 is switched from the direct feed circuit 3 to the inverter output side, and the AC output output from the inverter 20 is output to the AC output 2 via the switching device 60,
This device is in a normal operating state. When the commercial power supply voltage becomes abnormal, the AC / DC converter stops and the storage battery 40
As a result, power is supplied to the inverter 20, and a stable voltage is continuously supplied to the output 2.

Thus, the life of the storage battery, which is one of the most important parts of the AC uninterruptible power supply, is not known for the first time when an actual commercial power failure occurs, but the life judgment circuit start switch 44 is set in advance. By operating the life judgment circuit 43, the storage battery discharge switch 41
Is closed to discharge the storage battery 40 with the storage battery discharge resistance 42, and an increase in internal resistance due to the life of the storage battery is detected by the voltage change or the like.

Providing a special discharge circuit for investigating an increase in the internal resistance of the storage battery leads to an increase in the cost of the parts, and further, the reliability decreases due to an increase in the number of parts around the storage battery.

[0006]

According to the present invention, in such an AC uninterruptible power supply, by considering the starting sequence of each circuit in the device, it is possible to provide a discharge resistance for determining the life of a storage battery without special provision. The storage battery can be discharged at a constant power, and the voltage before the discharge of the storage battery and the voltage or voltage drop width after a certain time has elapsed can be measured safely and inexpensively at the end of the life of the storage battery or unconnected. An object of the present invention is to provide a power supply device having a function of detecting / determining.

[0007]

1 is a circuit diagram showing an embodiment of an AC uninterruptible power supply device of the present invention, and FIG. 2 is a flow chart diagram for determining its life. The operation of FIG. 1 will be described with reference to the flowchart of FIG.

When the AC uninterruptible power supply is activated, first, the charger 30 is activated by a signal from the control circuit 45. Then, after confirming for a certain period of time, it is confirmed that the storage battery voltage is equal to or higher than the "charge completed" level, and the inverter 20 is started. Since the AC / DC converter 10 is not operating yet, the power required for the inverter to operate without load is supplied from the storage battery 40 through the rectifying element 50.

Although the storage battery voltage drops due to this discharge current, the storage battery voltage is above the "charge complete" level during charging because the internal resistance of the storage battery, which is approaching the end of life, is increasing. Regardless, even a small discharge current in this mode causes a sharp voltage drop compared to a healthy storage battery. By detecting this phenomenon, the life of the storage battery is known, and a lamp or a buzzer is provided outside to notify the end of the life of the storage battery.

When the battery life determination is completed, the AC / DC converter 10 is activated for the first time at that point.
After confirming that inverter power supply is possible, switch 6
0 is switched from the direct feed circuit 3 to the inverter output side.

Alternatively, in the above, if the storage battery voltage is below the "charge completed" level before the charger 30 is started and the inverter is started, the storage battery is still in the state of being charged, and the life is judged by the above method. Therefore, the inverter 20 and the AC / DC converter 10 are started without judging the life, and after confirming that the inverter can be fed with electric power, the switch 60 is switched from the direct feed circuit 3 to the inverter output side.

According to the present invention, the storage battery can be discharged at a constant power by considering the starting order of each circuit in the AC uninterruptible power supply device, and the voltage before the discharge of the storage battery and the discharge constant time. The internal resistance of the storage battery can be estimated by measuring the voltage or the width of the voltage drop after the lapse of time, and the end of life of the storage battery can be easily detected and judged. It also functions as a non-connection alarm when the storage battery is not connected.

[0013]

As described above, according to the present invention, the storage battery can be discharged at a constant power by considering the starting order of each circuit in the device, and the voltage before the discharge of the storage battery The internal resistance of the storage battery can be estimated from the voltage or the voltage drop width after a certain period of discharge.
This makes it possible to easily detect and determine the end of the life of the storage battery with a simple configuration without providing a special discharge resistance for determining the life of the storage battery, and to increase the cost due to the increase in the number of parts and decrease the reliability of the entire device. It is possible to determine the life of the storage battery without generating

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of an AC uninterruptible power supply device of the present invention.

FIG. 2 is a flowchart of battery life determination.

FIG. 3 is a circuit diagram of a conventional device.

[Explanation of symbols]

 1 Commercial AC power supply 2 AC output 3 Direct transmission circuit 10 AC / DC converter 20 Inverter 30 Charger 40 Storage battery 45 Control circuit 50 Rectifying element 60 Switching device

Claims (1)

[Claims] 1. When the voltage of the regular power source drops or a power failure occurs,
In an AC uninterruptible power supply device that continuously supplies power to a load device by an inverter that uses a storage battery as a power source, the storage battery is discharged at a constant power by setting a startup sequence to a charger, an inverter, and an AC / DC converter. The internal resistance of the storage battery is estimated from the voltage before discharge of the storage battery and the voltage or voltage drop width after a certain time of discharge, and the end of life of the storage battery is easily detected and judged, and this judgment result is notified to the outside. An AC uninterruptible power supply equipped with functions.