JPS59104566A - Detector of abnormality of power source - Google Patents

Abstract

PURPOSE:To discriminate abnormalities such as loss and reduction of an AC power source by attaining a pulse signal on a basis of an AC signal obtained from a feeding terminal and attaining the voltage or current difference between this pulse signal and a reference AC signal generated synchronously with this pulse signal. CONSTITUTION:When an AC power source 21 is lost (indicated by a point A in Fig. b), n AC signal 121, an output signal 122 of a half-wave rectifying circuit 22, an output signal 123 of a square circuit 23, and an output signal 124 of a differentiating circuit 24 stops at the point A on the time axis in succession and the output signal of an oscillating circuit 25 disappears after a prescribed time based on the time constant of the circuit, and the output signal of a voltage detecting circuit 26 outputs a maximum value in an output circuit, thus detecting the loss of the AC power source 21. When the voltage is reduced, the AC signal 121 becomes smaller than a reference AC signal 125, and a potential difference with a fixed polarity is detected at the instant of comparison of signals by the voltage detecting circuit 26. By this device, the loss or the reduction of the AC power source is detected quickly similarly when it is generated in any phase.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides for immediate detection of voltage drop or loss in an abnormality-detected alternating current source of an electronic device or the like, thereby preventing a malfunction from occurring on the electronic device side. The present invention relates to a 1u source abnormality detection device that allows countermeasures to be taken.

Conventionally, this type of power supply abnormality detection device is shown in Figures 1 to N.
h, there are N to 9 shown in Figure 3, etc. In Figure 1, a relay 2 is provided after the power supply terminals 4 and 5 of an AC power source 1, and if the voltage of the AC power source 1 becomes lower than the holding pressure of the relay 2, the relay 2 is energized. This shows that the contact 6 of the relay 2 can be used to perform necessary actions on the devices connected to terminals 6 and 7 onward. FIG. 2 shows an example in which abnormality detection of the AC power supply 1 similar to that shown in FIG. 1 can be performed using a transistor 14. One circuit is provided in which DC voltage is divided by resistors 12 and 16, and this divided voltage is applied to the base of transistor 14 to utilize conduction/nonconduction between terminals 8 and 9. FIG. 5 shows an example of the principle in which abnormality detection of the AC power source 1 similar to that shown in FIGS. 1 and 2 is performed after converting it to a DC constant voltage power source. In other words,
The AC power supply 1 includes a rectifier/smoothing circuit 15 and a constant IA pressure circuit 16
is converted into a DC constant voltage power supply, and the voltage divided by the resistors 17 and 18 after the supply m terminals 4' and 5' is compared with the DC voltage source 19 for the set voltage voltage, and the minute voltage difference is amplified. An operational amplifier 20 is provided, and its output is used for the same purpose as above.

However, in Figure @2 and Figure 9P46, the same symbols as in Figure 1 indicate the same or corresponding parts.

The conventional device described above also has the following drawbacks and problems. That is, when an abnormality such as voltage drop or loss of AC power supply 1 occurs, the time it takes for each of the abnormality detection devices to detect the abnormality changes depending on the phase of occurrence, and it takes a long time to detect the abnormality. , for example 0.02 to 0.
06 seconds, and the loss of the AC' illumination 1 is easy to detect, but the voltage drop depends on the characteristics of the relay 2, the time constant of the rectifier 10 and smoothing capacitor 11, and the rectification/smoothing circuit 15.
Due to the time constant of , the constant voltage characteristics of the constant voltage circuit 16, etc.
The detection was slow and impractical, let alone protecting electronic equipment.

The present invention solves all the drawbacks and problems of the conventional devices as described above, and the details thereof will be explained below with reference to the drawings.

FIG. 4(a) shows a state in which the power supply abnormality detection device ytlJ of the present invention is connected to the power supply terminal 27 of the AC power supply 21 in parallel with the load, and the state is represented by a single line connection diagram. After rectifying the signal with the half-wave rectifier circuit 22, the rectangular amount is 1 m2
3, a rectangular signal is generated, the pulse signal is generated by capturing the rising edge of the rectangular signal through the differentiating circuit 24, and based on this pulse signal, the oscillation circuit 25 is started to obtain a reference AC signal, which is obtained from this and the above AC voltage #21. The AC IE source is input to the voltage detection circuit 6 to determine the voltage ratio or voltage difference between them, and based on the output of the voltage detection circuit 26, the AC IE source It can be used to determine abnormalities such as loss or decline of 21 and to take fail-safe measures for load equipment.

FIG. 4(b) represents the voltage waveforms at the output terminals of each of the constituent blocks of FIG. 4(a), and shows a specific example for explaining the main points of the present invention in detail.

First, in the case of a loss of the AC power source 21, if the loss occurs at point A on the time axis in FIG. 4(b), then the AC power source 21
1, the output signal 122 of the half-wave rectifier circuit 22, the output signal 126 of the rectangular circuit 26, and the output signal 124 of the differentiating circuit 24 stop after point A on the time axis, and the output signal of the transmitting circuit 25 125 disappears after opening based on the time constant of the circuit, and the voltage detection circuit 26
The output signal is, for example, a signal of the maximum value in the output circuit, representing the voltage ratio or voltage difference corresponding to the loss of AC power supply 21 from the time of loss of r or l of the AC power source 21. After that, AC electrician 1
If, at the start of the time axis, the phase is recovered with the phase shown in the AC signal 121 and deviates from r, the output signals of the half-wave rectifier circuit 22, the rectangular circuit 26, the differentiator circuit z4, the oscillator circuit 25, and the t1 pressure detection circuit 26 are 122.126.12 in Figure 4(b), respectively.
4. The situation after the time axis opening point of 125 and 1-6 is shown.

However, since the phase of the reference AC signal 125 lags behind the AC signal 121 in the output signal 126 of the voltage detection circuit 26, a positive and negative voltage difference is observed at the instant of comparison of these signals, and the polarity and voltage difference are Depending on the culm If, an appropriate signal representing the voltage ratio or voltage difference, for example intermediate between zero and the maximum value in the output circuit, is output. Then, assuming that the output signal 124 of the differentiating circuit 24 is obtained by the above-described series of signal processing at the same time as the start of the next normal cycle of the AC signal 121 at point C on the time axis, the transmitting circuit 25 calculates the output signal 124 at this point. The output signal 124 causes the start*1I111. After that, the fco reference AC signal 125 is outputted in synchronization with the AC signal 121, and the difference between the input signals to the voltage detection circuit 26 becomes J(, so the output signal disappears and disappears). j(ru.

Next, in the case of a voltage drop in the AC power supply 21, each suppression process will not be interrupted midway as in the case of the above-mentioned AC power supply z1 loss of 5 seconds, and as soon as the oxidation is reduced, the reference AC signal will simply be Since the magnitude of the AC signal 121 relative to 125 becomes relatively small (the phases are the same), the voltage detection circuit 26 detects a difference in polarity with constant polarity at the instant of comparison of these signals. A voltage ratio or voltage difference corresponding to the degree of polarity and potential difference is output.

As detailed above, according to the present invention, AC? Detection of voltage drop or loss of lj [121 is considerably faster than with conventional devices since the time delay in the detection circuit is small, and it can be detected equally quickly and accurately no matter what phase it occurs in. Therefore, on the load side such as various electronic devices that are supplied with power from this AC source 21, upon receiving the above detection signal, fail-safe measures such as preventing equipment malfunction or stoppage can be quickly taken. This is something that can be done.

[Brief explanation of the drawing]

Figure 1 shows the relay type, Figure 2 shows the transistor type, and the 6th type
The figures are explanatory diagrams of conventional examples of the constant voltage drop detection method, and Figure @4 is an explanatory diagram of the configuration and operation of the present invention. ... Rectangularization circuit Z4 ... Differentiation circuit 25.
...Oscillation filJfN! I26...Voltage detection circuit 27
...Power supply terminal No.8...Detection No. 48 terminal 121
, , Voltage wave of father flow signal from AC power supply 21 J)chi12
2. Output signal waveform 126 of half-wave rectifier circuit 2...
Output signal waveform 124 of rectangularization circuit 23...differentiation circuit 2
4 output signal waveform 125... Output signal waveform 126 of the oscillation circuit 25... Output signal waveform of the voltage detection circuit 26
・Start at the time of loss of AC power source 1 ・Start at the time of recovery of AC power source 21 ・Return point of @1 circuit 25 1 Concave'X3 Flash

Claims (1)

[Claims] A power supply abnormality detection device characterized in that an oscillator that operates in synchronization with an abnormality-detected alternating current source is connected, and an output signal from the oscillator is compared with a signal from the power supply.