JP3160148B2 - Abnormality detection device for power supply voltage in combustion control equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply voltage abnormality detection apparatus for a combustion control device for detecting a power supply voltage drop or power failure.

[0002]

2. Description of the Related Art Conventionally, this type of apparatus has been widely used in equipment in which a power failure or a drop in the power supply hinders subsequent operations. Also, in such devices, if an abnormality occurs in the operation of the device for some reason during operation, control for stopping the device is widely performed for safety measures. Therefore, when an abnormality occurs during the operation of such a device and the device is stopped, the user can know by this type of device whether or not the cause of the stop is an abnormality of the power supply voltage. The user can take appropriate action on the device.

Next, a conventional power supply voltage abnormality detecting device will be described. FIG. 7 is a circuit diagram showing a configuration of a circuit for detecting an instantaneous power failure of a power supply. Reference numeral 71 denotes an AC power supply, 72 denotes a transformer, 73 denotes a diode bridge, 74 denotes a smoothing capacitor, 75 denotes a resistor, 76 denotes a Zener diode, and 77 denotes a Zener diode. Indicates an amplifier. In this circuit, a pulse is output from the point a every one cycle of the AC voltage output from the AC power supply 71. Therefore, the instantaneous power failure of the AC power supply 71 is detected by monitoring the cycle (pulse interval) of this pulse. can do.

FIG. 8 is a circuit diagram showing a configuration of a circuit for detecting an instantaneous voltage drop of a power supply. The same reference numerals as those in FIG. 7 denote the same components, 81 denotes a resistor, and 82 denotes a variable. Shows the resistance. In this circuit, the AC power supply 7
Since a DC voltage proportional to the AC voltage output from 1 is obtained from the point b, a voltage drop of the AC power supply 71 can be detected by monitoring this DC voltage.

In the two circuits described above, the abnormality in the output voltage of the AC power supply 71 is detected by detecting the voltage on the secondary side of the transformer 72. There is also a configuration in which insulation is provided with respect to the above.

[0006] Incidentally, in a device equipped with such a power supply voltage abnormality detecting device, for example, a commercial combustion control device for controlling a motor or a boiler, a large current flows at the time of start-up, so that it is instantaneous. The power supply voltage drops. Therefore, as shown in FIG.
When only the combustion control device 91 is started in a state where is connected to the AC power supply 71, as shown in FIG. 10 (I), when the combustion control devices 91 and 92 are started simultaneously, as shown in FIG. As shown in II), when the combustion control devices 91 to 94 are started simultaneously, the output voltage of the AC power supply 71 fluctuates as shown in FIG.

[0007] Here, as shown in FIG. 10 (III), when the amount of drop in the power supply voltage is large, since the contactor of the motor controlled by the combustion control device causes chattering, the safety inside the combustion control device is reduced. The device is activated and the system is shut down. In addition, even when the AC power supply 71 fails, the safety device in the combustion control device operates and the system is stopped.

In the case where the system is stopped due to the above-mentioned cause, if the cause is a power failure, the operation may be resumed after confirming that the power supply is normal. However, if the power supply voltage drops abnormally and the system is stopped even though the power supply has not failed, the cause of such a voltage drop, for example, the load connected to the same power supply, An appropriate measure must be taken after examining the number or length and thickness of the electric wires connecting the power supply and the load.

[0009] In such a device, when an abnormality occurs in the power supply voltage and the device stops, the subsequent measures differ depending on whether or not the cause is a power failure.

[0010]

However, the circuit shown in FIG. 7 can detect a momentary power failure but cannot detect a voltage drop, and the circuit shown in FIG. Although it is possible to detect a large voltage drop, it is not possible to determine whether the cause is a power failure. Therefore, in a device equipped with a conventional power supply voltage abnormality detection device, when an abnormality occurs in the power supply voltage and the device stops, a great deal of time and effort is required to identify the cause.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a power supply voltage abnormality detecting device for detecting a power supply voltage drop when the power supply voltage drops and determining whether or not the cause of the voltage drop is a power failure. is there.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, an abnormality of a power supply voltage in a combustion control device according to the present invention.
The detection device rectifies the AC voltage supplied from the power supply and
When the rectified DC voltage falls below a predetermined value, a voltage drop signal
Voltage monitoring means for outputting a signal based on the AC voltage.
Amplifier to which pressure is applied, charged by the output of this amplifier
Capacitor and the voltage between the terminals of this capacitor
Compared with the voltage, the voltage between the terminals is lower than the predetermined voltage.
Power outage monitor equipped with a comparator that changes the output when
Viewing means, the voltage monitoring means and the power failure monitoring means.
Upon receiving the output, the voltage monitoring means generates the voltage drop signal.
If output, the output of the power failure monitoring means has changed
Sometimes a power failure is determined and the output of the power failure monitoring means changes
Determining means for determining a voltage drop when not performed;
A power outage or a voltage of the power supply according to the determination result of the determination means;
Display means for displaying that the vehicle is descending .

[0013]

According to the present invention constructed as described above, when the power supply voltage drops, the voltage monitoring means detects it,
If a power failure occurs, the power failure monitoring means detects it. In response to the outputs of the two monitoring means, when a voltage drop occurs, the determination means determines whether or not the cause of the voltage drop is a power failure, and the display means displays a voltage drop or a power failure according to the result.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing a configuration of one embodiment of the present invention, and the same reference numerals as those in FIG. 7 denote the same components.
In Figure 1, 1 is an AC power source, 2 is a transformer, 3 diode bridge, 4 is a smoothing capacitor. Also, 1
Reference numerals 0 to 16 denote resistors, 17 denotes a capacitor, 18 and 19 denote comparators, 20 denotes an inverter, 21 and 22 denote AND circuits, 23 and 24 denote transistors, and 25 and 26 denote LEDs.

Here, the voltage of the AC power supply 1 is 200 V AC.
And the power supply voltage is A
A voltage having the same value as the voltage output from the point b when the voltage reaches C180V is supplied. The capacitor 17 is charged by the pulse output from the point a, and is discharged via the resistor 16 when no pulse is output from the point a. Then, a voltage having the same value as the inter-terminal voltage of the capacitor 17 when the interval between pulses output from the point a becomes 50 msec is input to the + terminal of the comparator 19.

Next, the operation of the embodiment constructed as described above will be described. When the voltage of the AC power supply 1 is normal, the outputs of the comparators 18 and 19 are both "L", the outputs of the AND circuits 21 and 22 are both "L", and the transistors 23 and 24 are turned off. Therefore, the LEDs 25 and 26 do not light up.

In such a state, when a power failure occurs in the power supply 1, the voltages at points a and b change as shown in FIGS. 2 (a) and 2 (b). The state of this momentary power outage is 50
Since the output voltage at the point b and the voltage between the terminals of the capacitor 17 both decrease for more than msec, the comparators 18, 1
9 are both "H", the output of the AND circuit 21 is "H", and the output of the AND circuit 22 is maintained at "L". Accordingly, only the LED 25 is lit to indicate that a power failure has occurred. In addition, even though the power supply 1 is not interrupted, the power supply voltage is momentarily changed to AC180V for some reason.
When the voltage drops below, the voltages at the points a and b are as shown in FIG.
It changes as shown in (a) and (b). In such a state, the output of the comparator 18 becomes “H” and the output of the comparator 19 becomes “L”.
1 is "L", and the output of the AND circuit 22 is "H". Therefore, only the LED 26 is turned on to indicate that a voltage drop has occurred.

In this embodiment, the transistor 2
A latch circuit may be provided on the input side of 3, 24 so that when the LED 25 or the LED 26 is turned on, the lighting is continued until the latch circuit related to the turned on LED is reset.

Next, another embodiment of the present invention using a microcomputer will be described. FIG. 4 is a block diagram showing the configuration of another embodiment of the present invention, in which the same reference numerals as those in FIG. 1 denote the same components.
Is an interactive input / output device for displaying "power failure" or the like. In the following program, the “value at point b” refers to the analog voltage output from point b as A /
This is the value after D conversion.

FIG. 5 is a flowchart showing a procedure to be executed by the microcomputer 41. First, in step S50, the value at point b is read. Next, the process proceeds to step S51, and the time is measured by the timer 1,
After elapse of 0.5 sec, the process proceeds to step S52, and the value of the point b input earlier is set to B. In step S53, the current b
The value of the point is read and the value is set to A. In step 54, BA is calculated and it is determined whether or not the value is 10 or more. That is, in this step S54, 0.5 seconds
It is determined whether or not the output voltage at point b has dropped by 10 V or more. If the determination is affirmative, the process proceeds to step S55, and if the determination is negative, the process proceeds to step S55. In step S55, it is determined whether there is a momentary power failure flag indicating that a momentary power failure has occurred. If the momentary power failure flag is present, the process proceeds to step S57, and if there is no momentary power failure flag, the process proceeds to step S56. This momentary stop flag will be described later with reference to FIG. In step S56, an instantaneous drop flag indicating that the power supply voltage has dropped instantaneously even though there is no power failure is set to O.
Set to N. In step S57, the timer 1 is cleared.
In step 58, the presence or absence of the instantaneous stop flag or instantaneous descent flag is determined.
Proceeding to 59, the display according to the flag is displayed on the input / output device 42.
To be performed. If neither flag is present, the process returns to step S51. Thereafter, steps S51 to S59 are repeated.

Next, the instantaneous stop flag will be described with reference to FIG. FIG. 6 is a flowchart showing an interrupt program executed every 2 msec during execution of the main program shown in FIG. First, it is determined in step S61 whether or not a pulse has been input from point a. If a pulse has been input, the flow proceeds to step S62 to clear the timer 2, and if no pulse has been input, the flow proceeds to step S63. Then, the time is measured by the timer 2.

In step S64, it is determined whether or not the time measured by the timer 2 is 50 msec or more.
That is, in step S64, it is determined whether a power failure has occurred for a time period of 50 msec or more. If the determination is affirmative, the process proceeds to step S65 to turn on the instantaneous stop flag, and then returns to the main program. If the determination is negative, the process returns to the main program. As described above, according to the present embodiment, it is possible to detect a momentary power failure or a momentary voltage drop not caused by the power failure, and to that effect,
2 can be displayed.

[0023]

As described above, according to the present invention, when the power supply voltage drops momentarily, the determination means determines whether or not the cause is a power failure, and the display means displays the result. So that when the power supply voltage drops, the voltage drop can be detected,
It is possible to know whether or not the cause of the voltage drop is a power failure.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a waveform diagram showing output waveforms at points a and b in FIG.

FIG. 3 is a waveform chart showing output waveforms at points a and b in FIG.

FIG. 4 is a configuration diagram showing a configuration of another embodiment of the present invention.

FIG. 5 is a flowchart showing a procedure of a main program to be processed by the microcomputer shown in FIG. 4;

FIG. 6 is a flowchart showing a procedure of an interrupt program to be processed by the microcomputer shown in FIG. 4;

FIG. 7 is a circuit diagram showing a configuration of a conventional power supply voltage abnormality detection circuit.

FIG. 8 is a circuit diagram showing a configuration of a conventional power supply voltage abnormality detection circuit.

FIG. 9 is a circuit diagram showing a connection relationship of a combustion control device.

FIG. 10 is a waveform diagram showing a power supply voltage waveform in the circuit shown in FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC power supply 2 Transformer 3,73 Diode bridge 4,17,74 Capacitor 10-16,75 Resistance 18,19 Comparator 20 Inverter 21,22 AND circuit 23,24 Transistor 25,26 LED 41 Microcomputer 42 I / O device

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G05F 1/10 304 H02H 3/24

Claims (1)

(57) [Claims] An AC voltage supplied from a power supply is rectified,
When the rectified DC voltage falls below a predetermined value, the voltage drops
Voltage monitoring means for outputting a signal,An amplifier to which a voltage based on the AC voltage is applied,
The capacitor charged at the output of the amplifier and this capacitor
The voltage between the terminals is compared with a predetermined voltage.
When the voltage falls below a predetermined voltage, the
Equipped with a parator A power failure monitoring unit that receives outputs of the voltage monitoring unit and the power failure monitoring unit.
When the voltage monitoring means outputs the voltage drop signal,
If the power failure monitoring meansOutput changesStop when
Power outage monitoring meansOutput changesNot
Sometimes determining means to determine a voltage drop and,  The power outage or power failure of the power
Display means for indicating that a pressure drop has occurred.
Abnormality detection device for power supply voltage in firing control equipment.