JPH07170678A - Ac uninterruptible power-supply apparatus - Google Patents

Abstract

PURPOSE:To automatically start and stop an uninterruptible power-supply apparatus so as to be interlocked with a power-supply switch for a load apparatus by a method wherein a load current is detected, the operating state of the load apparatus is judged on the basis of a detected value and, on the basis of a judged result, the uninterruptible power-supply apparatus is automatically changed over to an operating state or a standby state. CONSTITUTION:When a load apparatus which is connected to an AC output 2 for an AC uninterruptible power-supply apparatus is stopped, a commercial AC power supply 1 is output to the AC output 2 via a direct transmission circuit 3 and a changeover device 41. When the load apparatus is set to an operating state, a current starts to flow. Its current value is detected by a current detector 50, and it is input to an operation/stop control circuit 40. Then, the control circuit 40 judges, by the detected value, that the load apparatus is in a starting state, it starts an inverter 30 and a rectifier 10, and it changes over the changeover device 41 to the side of the inverter. On the other hand, when the load apparatus is stopped and the detected value of the detector 50 becomes sufficiently small, the control circuit 40 stops the inverter 30 and the rectifier 10, and it changes over the changeover device 41 to the side of the direct transmission circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an 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 such 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 delivery circuit, 10 is a rectifier, 20 is a storage battery, 30 is an inverter, 40 is a start / stop control circuit,
43 is a start / stop switch, 42 is an input switch, 41
Is a switch. In such a conventional device, normally, when the input switch 42 is turned on, the commercial AC power supply 1 supplies power to the AC output 2 through the direct feed circuit 3 and the switch 41.

Here, the run / stop switch 43 is set to "run".
Switching to the rectifier 10 from the start / stop control circuit 40.
And a start signal is sent to the inverter 30 to start each. Then, the commercial AC power supply 1 is converted into DC power by the rectifier 10, charges the storage battery 20, and inputs it to the inverter 30. If the inverter output voltage is normal, the switch 41 switches from the direct feed circuit 3 to the inverter output side, and the AC output output from the inverter 30 is output to the AC output 2 via the switch 41.

Further, when the commercial AC power supply 1 fails, power is continuously supplied from the storage battery 20 to the AC output 2 via the inverter 30 and the switch 41 without interruption.

Generally, in this type of AC uninterruptible power supply, the input switch 42 is normally kept on, and normal operation is often performed only by the run / stop switch 43. In such a usage mode, when the load device is in a stopped state, in order to save energy or prevent the operation of the unnecessary AC uninterruptible power supply due to the artificial interruption of the original switchboard, turn on the power switch of the output load device. on/
It was necessary to operate the run / stop switch of the AC uninterruptible power supply each time it was turned off.

If the operation due to unnecessary power failure is frequently repeated, such as when the load device is in a stopped state as described above, the battery is frequently charged and discharged, which shortens the life of the battery. On the other hand, if the load device is operated without forgetting to turn on the run / stop switch, the inverter will not operate and AC output 2
There was a case where the power was lost.

[0007]

DISCLOSURE OF THE INVENTION In such an AC uninterruptible power supply, the present invention determines the operation stop state of the load device by detecting the load current. When the stop state is detected, the inverter is stopped and the switching device is switched. Is switched to the direct-delivery circuit and automatically put into the stop standby state (there is no unnecessary discharge from the storage battery even if the commercial power supply fails at this time).
It is an object of the present invention to provide a power supply device which eliminates the above-mentioned drawbacks of the power supply device by adopting a system in which when the load device is started, the load device is detected and the inverter is started and the switching device is switched to the inverter side to supply power to the inverter.

[0008]

FIG. 1 is a circuit diagram showing an embodiment of the AC uninterruptible power supply of the present invention. The difference from the circuit diagram of the conventional example shown in FIG. 2 is that an input switch 42 and a run / stop switch 43 are provided. Is provided and a current detector 50 is provided on the output side, and the detected value is set as one of the operating conditions of the AC uninterruptible power supply.

To explain the operation of FIG. 1, first, when the load device connected to the output of the present apparatus is stopped, the commercial AC power source 1 passes through the direct feed circuit 3 to the AC output 2 via the switch 41. It is outputting. At this time, when the load device is in the operating state, current starts flowing through the above path. The current value is detected by the current detector 50 and input to the run / stop control circuit 40. From the detected value, it is determined that the load device is in the activated state, the inverter and the rectifier are activated, and after confirming that the inverter output voltage is stable, the switch 41 is switched to the inverter side.

Further, in this state, when the load device is stopped and the current value detected by the current detector 50 becomes sufficiently small, it is confirmed for a certain period of time, the inverter and the rectifier are stopped, and the switch 41 is connected to the direct circuit side. Switching, the AC uninterruptible power supply goes into the stand-by state for stop.

According to the present invention, since the AC uninterruptible power supply can be started and stopped automatically in conjunction with the power switch of the load device, the operation of the operation / stop switch of the AC uninterruptible power supply is unnecessary. Therefore, the operation method of this device can be greatly simplified. Further, when the present apparatus is installed and used in a place distant from the load apparatus, this AC uninterruptible power supply apparatus can be automatically remote-controlled by the power switch of the load apparatus.

[0012]

As described above, according to the present invention, when the load device is in a stopped state, the commercial AC power source supplies power to the load device via the direct transfer circuit 3, and the inverter 30 and the rectifier 20 are in a stop standby state. When the load device is activated, the inverter 30 and the rectifier 20 are automatically activated, and the inverter output is supplied to the load device. As described above, since the AC uninterruptible power supply can be automatically started and stopped in conjunction with the power switch of the load device, the usage of the device can be greatly simplified. In addition, remote control of this device is possible.

[Brief description of drawings]

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

FIG. 2 is a circuit diagram of a conventional device.

[Explanation of symbols] 1 Commercial AC power supply 2 AC output 3 Direct transfer circuit 10 Rectifier 20 Storage battery 30 Inverter 40 Start / stop control circuit 41 Switcher 50 Current detector

Claims (1)

[Claims] 1. When the voltage of the regular power source drops or a power failure occurs,
In an AC uninterruptible power supply system that continuously supplies power to a load device by an inverter that uses a storage battery as a power source, it is equipped with a device that detects the load current and a circuit that determines the operating state of the load equipment from the detected value. An AC uninterruptible power supply that can automatically switch the operating mode to standby or standby depending on the result, and eliminates the operation switch that is operated by a person on a daily basis.