JPH02136038A - Power switching apparatus - Google Patents

Abstract

PURPOSE:To supply a stable output voltage by conducting a switching operation rapidly through switching an output voltage from a power supply according to the rate of change of voltage. CONSTITUTION:If any abnormality occurs in a power supply apparatus 1 and an output voltage 10 lowers abruptly at the time T1, an average value voltage 30 changes gently due to a time constant. On the other hand, the rate of voltage change 42 becomes larger (the absolute value becomes larger) abruptly in the negative direction and becomes zero thereafter. In this case, when a threshold value VTH larger in the absolute value than the normal rate of change is set beforehand, a switching signal 40 becomes a logical value '1' at the time T1 and an output voltage 70 is switched to the output voltage 20 from a power supply apparatus 2 by a switch control circuit 5 and a switch 6.

Description

TECHNICAL FIELD The present invention relates to a power supply switching device, and more particularly to a power supply switching device that selectively sends out output voltages supplied from a plurality of power supply devices.

Conventional technology Conventionally, this type of power switching device determines that a voltage abnormality has occurred when the average value of the output voltage of a certain power supply device over a predetermined period of time falls below a preset threshold voltage, and switches the output voltage of a certain power supply device to another power supply device. The output voltage was switched to 1 and was sent out.

However, in the conventional power supply switching device described above, since the integrated value, which is the average value of the output voltage supplied from the power supply device over a predetermined time, is the subject of judgment, even if there is a large voltage fluctuation during integration, it is still within the integration time. However, there was a drawback that the switching operation was not performed and it was not possible to switch quickly.

SUMMARY OF THE INVENTION An object of the present invention is to provide a power switching device that can shorten switching time.

The power supply switching device of the present invention is a power supply switching device that selectively sends out power supply voltages supplied from a plurality of power supplies, and the power supply switching device selectively sends out power supply voltages supplied from a plurality of power supplies, and the power supply switching device selectively sends out power supply voltages that are currently being sent out. an average voltage sending means for sending out an average value voltage, a change rate signal sending means for sending out a change rate signal that is a change rate of the average value voltage, and when the change rate is outside a predetermined range, the output It is characterized by having a switching means for switching from the power supply voltage to another power supply voltage and transmitting it.

K1 top Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of a power supply switching device according to the present invention. In FIG. It is configured to include a switch control circuit 5, and a switch 6, and outputs the output voltage 10 or 20 of the power supply device 1 or 2 as an output voltage 70 alternatively.

The voltage detection sensor 3 rectifies the alternating current output voltage 10 or 20 from the power supply device 1 or 2, and calculates the average value over a predetermined period of time.

The voltage abnormality determination circuit 4 differentiates the average voltage 30 that is the output of the voltage detection sensor 3, and sends out a switching signal 40 when the voltage change rate, which is the result of the differentiation, shows a value outside a predetermined range.

The switch control circuit 5 responds to the switch signal 40 to output the drive signal 5.
0 to the switch 6, and a well-known relay drive circuit is used.

The switch 6 outputs a voltage of 10 or 20 depending on the drive signal 50.
is alternatively sent out as an output voltage 70, and is constructed using a well-known relay.

Next, the configuration and operation of the voltage detection sensor 3 and the voltage abnormality determination circuit 4 will be explained using FIGS. 2 and 3.

Note that in the normal state, the output voltage 1 of the power supply device 1
0 as the output voltage 7o.

FIG. 2 is a block diagram showing the internal configuration of the voltage detection sensor 3 and the voltage abnormality determination circuit 4, and parts equivalent to those in FIG. 1 are designated by the same symbols.

In FIG. 2, the voltage detection sensor includes a time averaging circuit 31 for calculating an average value every predetermined time. Further, the voltage abnormality judgment circuit 4 includes a differentiating circuit 41, a voltage change rate 42 which is the output thereof, and a preset threshold value 43.
It is configured to include a comparison circuit 44 for comparing the .

It is assumed that the differentiating circuit 41 is constituted by a well-known CR time constant circuit, and its time constant is sufficiently small.

Next, the operation shown in FIG. 2 will be explained using FIG. 3.

FIG. 3 is a waveform diagram showing the output voltage 10 of the power supply device 1, the average value voltage 30 from the voltage detection sensor 3, the voltage change rate 42 from the differentiation circuit 41, and the switching signal 40.

Under normal conditions, the output voltage 10 is
When the signal is input to , it is rectified by a rectifier circuit (not shown) and then integrated by a time averaging circuit 31 . Then, an average value voltage 30 as shown in the figure will be sent out. Next, by differentiating this with a differentiating circuit 41, a voltage change rate 42 is calculated. This voltage change rate 4
2 is compared with a preset threshold value -VTH.

Next, some abnormality occurs in the power supply device 1 and the time T1
Suppose that the output voltage 10 suddenly drops at . Then, the average voltage 30 changes slowly due to the time constant.

On the other hand, the voltage change rate 42 suddenly increases in the negative direction (the absolute value is large) and then becomes zero. At this time, if a threshold giVTl+ whose absolute value is larger than the normal rate of change is set in advance, the switching signal 40 becomes the logical value "1." at time T1, and the switching device control circuit 5 and the switching device 6 control the output voltage 70.
will be switched to the output voltage 20 from the power supply device 2.

On the other hand, in the conventional power supply switching device, since the average value voltage 30 is the subject of judgment when sending out the switching signal 40, the switching signal 40 is set at time T2 after time T1.
has a logical value of "1", that is, due to the time constant when calculating the average value, at time TI, the average value voltage 30 is within the normal fluctuation range, so the switching signal 40 is not sent. This is because the switching signal 40 is not sent out until the time T2 when the average voltage 30 becomes lower than the normal value. Therefore, according to the present invention, the switching operation is performed earlier than the conventional method by the time (T2-71).

Note that in this embodiment, the switching operation is performed when the voltage change rate becomes larger in the negative direction than a predetermined dark value, but in addition, the switching action is also performed when the voltage change rate becomes larger in the positive direction. You can do it like this.

In this case, two comparison circuits may be provided.

Fish J! υExample As explained above, the present invention has the advantage that by switching the output voltage from the power supply according to the voltage change rate, the switching operation can be performed quickly and a stable output voltage can be supplied. be.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a power supply switching device according to an embodiment of the present invention, FIG. 2 is a block diagram showing the internal configuration of the voltage detection sensor and voltage abnormality determination circuit in FIG. 1, and FIG. FIG. 3 is a waveform chart showing the operation shown in FIG. Explanation of symbols of main parts 3...Voltage detection sensor 4...Voltage abnormality judgment circuit 6...Switcher Fig. 3

Claims (1)

[Claims] (1) A power supply switching device that selectively sends out power supply voltages supplied from a plurality of power supplies, the average voltage that sends out an average value voltage that is the average value over a predetermined time of the output power supply voltages that are currently being sent out. a rate-of-change signal transmitting means for transmitting a rate-of-change signal that is a rate of change of the average voltage; and a rate-of-change signal transmitting unit configured to switch from the output power supply voltage to another power supply voltage when the rate of change is outside a predetermined range. 1. A power supply switching device comprising: switching means for transmitting power.