JPH0946930A - Ac switch for switching bypass power of uninterruptible power unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mitigate the influence of instantaneous power failure of a bypass power source by keeping ON condition while the switch to supply the bypass power between the bypass power source and load is on. SOLUTION: An uninterruptible power unit 1 stops power supply by the occurrence of abnormality. Moreover, when an ON signal is inputted into the semiconductor element 32 of an AC switch 3, the semiconductor element 32 is turned on, and supplies power through a breaker 5 from a bypass power source 4. Accordingly, switching without a break from the uninterruptible power unit 1 to the bypass power source 4 can be realized. Furthermore, the semiconductor element 32 of an AC switch 3 keeps the ON condition also after turning on of the switch 31 of the AC switch 3. Accordingly, the influence of the instantaneous power failure of the bypass power source can be prevented to its minimum by making the semiconductor element of the AC switch act upon it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC switch for switching a bypass power supply of an uninterruptible power supply which switches between an output of an uninterruptible power supply and an output of a bypass power supply.

[0002]

2. Description of the Related Art FIG. 2 shows a power supply system according to the present invention, in which 1 is an uninterruptible power supply, 2 is a load, and 3 is A.
C switch, 4 is a bypass power supply, and 5 is a circuit breaker.

In FIG. 2, the AC switch 3 for switching the power supply from the uninterruptible power supply 1 to the load 2 to the power supply from the bypass power supply 4 is used as follows. Normally, when an abnormality occurs in the uninterruptible power supply device 1 for some reason while the uninterruptible power supply device 1 is supplying power to the load 2, the means provided in the uninterruptible power supply device 1 supplies power to the load 2. Is stopped. At the same time, an ON signal is sent from the control unit (not shown) to the switch 31 and the semiconductor element 32 of the AC switch 3. Here, the semiconductor element 32 shown in the figure is unidirectional with a thyristor symbol, but it is generally required to be bidirectional and is configured in antiparallel. Further, the semiconductor element is not limited to the thyristor as a matter of course.

FIG. 3 shows the operation of each function of the power supply switching. That is, in FIG. 3, the uninterruptible power supply 1 stops power supply due to the occurrence of an abnormality. AC
When an ON signal is input to the semiconductor element 32 of the switch 3,
The semiconductor element 32 is turned on, and power is supplied to the load 2 from the bypass power supply 4 through the breaker 5. The circuit breaker 5 is usually provided to ensure safety and reliability, and is normally on. Therefore, the switching of the power supply from the uninterruptible power supply 1 to the bypass power supply 4 is performed at an extremely high speed, and the load 2 can be instantaneously switched.

An ON signal is also sent to the switch 31 of the AC switch 3, but since the switch is a mechanical switch, it takes 10 ms to reach the ON state. Instantaneous switching cannot be realized by itself. Furthermore, the semiconductor element 32 alone requires a continuous rated energizing current capacity, which is large and expensive, which is not a good idea. For this reason, the AC switch 3 is configured as shown in FIG. 2, and further, after the switch 31 is turned on, the semiconductor device 32 is configured so that current can be reliably drawn from the semiconductor device 32 to the switch 31. The semiconductor element 32 is turned off by stopping the sending of the ON signal to the semiconductor device 32. This is as shown in FIG. Therefore, the semiconductor element 32 can be rated for a short time, and the device can be made small and inexpensive.

[0006]

However, when a so-called electromagnetic contactor of electromagnetic attraction type is frequently used for a switch of an AC switch and a momentary power failure occurs in a bypass power supply, the switch is turned off and then turned on again. Became,
Therefore, there has been a problem in that the power-off period is extended for the load.

However, the object of the present invention is to
The AC switch that skillfully operates the semiconductor element of the C switch to reduce the influence of the momentary power failure of the bypass power supply,
To provide.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned points, and a means for solving the problem is to insert the bypass power supply and the load into the output of the uninterruptible power supply and the bypass. In an AC switch for bypass power supply switching of an uninterruptible power supply in which a switch for switching the output of a power supply and a semiconductor element are connected in parallel, the semiconductor element continues to be in an ON state while the switch of the AC switch is ON. Is configured to hold.

By the solving means, the following actions can be achieved. That is, since the semiconductor element of the AC switch can maintain the ON state by the ON signal, even if the switch is turned off due to a momentary power failure in the bypass power supply, if the bypass power supply is restored, power can be supplied to the load without delay. You can

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION
Between the bypass power supply and the load, there is provided an AC switch in which a switch for supplying the bypass power supply and a semiconductor element which maintains an ON state while the switch is ON are connected in parallel. Is. Hereinafter, the present invention will be described in more detail with reference to the drawings.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the functions of the respective parts of the present invention represented in a manner similar to FIG. 3 in order to facilitate understanding of the present invention. That is, the uninterruptible power supply 1 stops the power supply due to the occurrence of an abnormality, and when the ON signal is input to the semiconductor element 32 of the AC switch 3, the semiconductor element 32 is turned on and the circuit breaker 5 is disconnected from the bypass power supply 4. As in the case of FIG. 3, the load 2 is supplied with power via the load 2 and thus the instantaneous switching from the uninterruptible power supply 1 to the bypass power supply 4 can be realized.

Further, the semiconductor element 32 of the AC switch 3
Is used so that the ON state is maintained even after the switch 31 of the AC switch 3 is turned on as shown in the figure. Here, the semiconductor element drive circuit, which is the source of the ON signal to the semiconductor element 32, must naturally be able to send the ON signal even during the momentary power failure of the bypass power supply 4,
It is relatively easy to implement power supply strengthening measures to this extent. Also, the fact that the switch 31 of the AC switch 3 continues to send the ON signal even after it is turned ON means that the semiconductor element 32
The ON signal may be the same logic as the ON signal of the switch 31 and can be simpler than the configuration of FIG.

Now, the voltage drop of the semiconductor element 32 is practically much larger than that of the switch 31, and the semiconductor element 32
Switch 31 that is connected in parallel even if the 32 ON signal continues
Is turned on, the current flows from the semiconductor element 32 to the switch 31.
Move to. That is, the current path to such a load 2 is as illustrated. That is, if the switch 31 is in the ON state, no current flows through the semiconductor element 32 even if an ON signal is input, and therefore, the semiconductor element 32 having a conventional short-time rating can be used.

[0014]

As described above, according to the present invention, A
It is possible to provide a device having a remarkable practical effect in which the semiconductor element of the C switch is skillfully acted to minimize the influence of the momentary power failure of the bypass power supply and the continuity of the power supply to the load is enhanced. To do.

[Brief description of drawings]

FIG. 1 is an operation explanatory view shown for explaining functions of respective parts of the present invention.

FIG. 2 is a system diagram showing a power supply system according to the present invention.

FIG. 3 is an operation explanatory view shown for explaining the functions of respective parts of the conventional technique.

[Explanation of symbols]

 1 uninterruptible power supply 2 load 3 AC switch 31 switch 32 semiconductor element 4 bypass power supply 5 circuit breaker

Claims (1)

[Claims] 1. A switch for bypass power supply of an uninterruptible power supply in which a switch and a semiconductor element which are inserted between a bypass power supply and a load and switch between an output of the uninterruptible power supply and an output of the bypass power supply are connected in parallel. An AC switch for bypass power supply switching of an uninterruptible power supply, wherein the semiconductor element has a function of continuously maintaining an ON state while the switch is ON.