JP2001343119A - Combustion control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce cost and also reduce the size of a circuit. SOLUTION: A combustion control device 1 is constituted such that a voltage from a power source 2 is inputted to the primary side of a transformer 6, the primary voltage is switched by a switching source control part 5, and its secondary voltage is fed to a combustion part 15. The combustion control device comprises an output voltage monitoring means 11 to output a monitoring signal corresponding to the secondary voltage, a combustion control means 16 to effect control of the combustion part 15, and a combustion forced stop means 12 to command the combustion part 15 and forcibly stop combustion. The output voltage monitoring means 11 is brought into instantaneous lowering of a secondary voltage owing to instantaneous service interruption or instantaneous voltage lowering and outputs an emergency period signal to the combustion control means 16. The combustion control means 16 receives the emergency period signal to stop combustion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a configuration in which a voltage from a power supply is input to a primary side of a transformer, the primary voltage is switched by a switching power supply control section, and the secondary voltage is supplied to a combustion section. The present invention relates to a combustion control device having a power supply unit having the same.

[0002]

2. Description of the Related Art In a conventional combustion control apparatus, it is necessary to provide a circuit for detecting an instantaneous power failure and an instantaneous voltage drop on the primary side of a power supply unit in order to prevent a combustion failure due to an instantaneous power failure and an instantaneous voltage drop.

[0003]

However, if a circuit for detecting an instantaneous power failure and an instantaneous voltage drop is provided on the primary side of the power supply unit as in the above-mentioned conventional combustion control device, the cost increases and the circuit becomes expensive. Also had the problem of becoming larger.

[0004] The present invention has been proposed in view of the above,
It is an object of the present invention to provide a combustion control device that can reduce costs and reduce the size of a circuit.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, a voltage from a power supply is input to a primary side of a transformer, and the primary voltage is supplied to a switching power supply control unit. An output voltage monitoring unit that monitors the secondary voltage and outputs a monitoring signal according to the secondary voltage, wherein the combustion control device includes a configuration that switches and supplies the secondary voltage to the combustion unit; A combustion control unit for controlling the unit, and a forced combustion stop unit for forcibly stopping combustion by instructing the combustion unit. The output voltage monitoring unit includes an instantaneous power failure or an instantaneous voltage drop in the power supply unit. In response to the drop in the secondary voltage, an emergency signal is output to the combustion control means and the forced combustion stop means, and the combustion control means and the forced combustion means stop the combustion in response to the emergency signal.
It is characterized by:

According to a second aspect of the present invention, in addition to the configuration of the first aspect of the present invention, there is provided a forced combustion stopping means for instructing the combustion section to forcibly stop combustion. The output voltage monitoring means outputs an emergency signal to the combustion control means and the forced combustion stop means in response to an instantaneous power failure or a drop in the secondary voltage due to an instantaneous voltage drop in the power supply unit, The forcible stop means stops the combustion in response to the emergency signal.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a combustion control device according to the present invention. In the figure, a combustion control device 1 of the present invention is a device for controlling combustion of a combustion device such as a gas water heater, and has a commercial AC power supply 2
And a rectifier circuit 3, a switching power supply controller 5, and a transformer 6.

The power supply voltage of the commercial AC power supply 2 is applied to a pair of opposed connection points of a rectifier circuit (for example, a bridge rectifier) 3 and is taken out as a DC voltage from the other pair of opposed connection points. After this DC voltage is smoothed by the smoothing capacitor 4, the DC voltage is applied to a series connection composed of the primary winding 61 of the transformer 6 and the switching power supply controller 5.

The switching power supply control section 5 has a configuration including a switching element (not shown), and controls the switching element to be turned on and off at a predetermined frequency to thereby reduce the primary current flowing through the primary winding 61 of the transformer 6. This causes the secondary voltage to be output to the secondary winding 62 side of the transformer 6.

The transformer 6 is provided with another secondary winding 621 having a common iron core 63. One end of the secondary winding 621 is connected to the other end via a photocoupler (photodetector) 11a. Are directly connected to the switching power supply control unit 5, respectively, so that the secondary voltage generated in the secondary winding 621 is applied to the switching power supply control unit 5 via the photocoupler 11a.

A secondary voltage generated on one secondary winding 62 is smoothed by a smoothing circuit including a diode 8 and a smoothing capacitor 9. Both terminals 9a of this smoothing capacitor 9,
9b, the output voltage monitoring circuit 20, the combustion unit 15,
Control unit consisting of microcomputer (combustion control means)
16 are connected in parallel. Note that the control unit 16
A combustion control such as a valve opening control of a gas supply valve or a rotation speed control of a fan motor is performed by commanding the combustion unit 15.

A switching element 14 is interposed between one terminal of the output voltage monitoring circuit 20 and one terminal of the combustion section 15. A forced combustion stop circuit (combustion forced stop means) 12 and a photocoupler (photodetector) 11b are connected in series to a base terminal of the switching element 14. It is connected between the terminal and another terminal of the combustion section 15.

Between the output voltage monitoring circuit 20 and the terminal 9a, three photocouplers (LEDs) 10a and 10
b and 10c are connected in parallel.

A photocoupler (photodetector) 11c and a resistor 18 are connected in series to the other terminal of the control unit 16, and a resistor 19 is interposed between the connection point 21 and the control unit 16. ing.

In the combustion control device 1 having the above-described structure, the secondary power generated at both ends of the secondary winding 62 of the transformer 6 is smoothed and then output from the output voltage monitoring circuit 20, the combustion unit 15 and the control unit 16. It is supplied to each part. Output voltage monitoring circuit 20
Detects and monitors the smoothed secondary voltage, and according to the magnitude of the detected secondary voltage,
a, 10b, and 10c are blinked. The blinking signal is received by the photocouplers 11a, 11b, and 11c and converted into an electric signal, which is used as a monitoring signal or an emergency signal indicating abnormality.

The switching power supply control unit 5 grasps the state of the secondary voltage based on the optical coupling between the photocoupler 10a and the photocoupler 11a, and changes the switching cycle and frequency according to the state. By doing so, the switching control of the primary voltage is performed so that the secondary voltage becomes the specified voltage.

By the way, the secondary voltage control based on the power supply voltage is normally performed. However, when an instantaneous power failure or an instantaneous voltage drop occurs on the power supply side, electric power is supplied from the commercial AC power supply 2 to the switching power supply control unit 5. Therefore, the power stored in the smoothing capacitor 4 is used. This capacitor power can be output for a certain period of time, but thereafter, as time passes, the capacitor power decreases, and the power supplied to the transformer 6 decreases with the decrease. At the switching frequency and cycle, the secondary voltage drops significantly.

On the other hand, the control unit 16 includes the photocoupler 10
The voltage V1 corresponding to the secondary voltage is input via the resistor 19 according to the optical coupling between the photocoupler c and the photocoupler 11c. A threshold value V01 for determining whether the secondary voltage is normal is set in the control unit 16 in advance,
If the input voltage V1 is within a range that is not problematic compared with the threshold value V01, the control unit 16 determines that the power supply side is normal and instructs the combustion unit 15 to perform normal combustion control.
On the other hand, if the input voltage V1 is in a problematic range as compared with the threshold value V01, it is determined that an instantaneous power failure or an instantaneous voltage drop abnormality has occurred on the power supply side, and the combustion unit 15 is instructed to stop combustion. .

Further, a voltage V2 corresponding to a secondary voltage is applied to the forced combustion stop circuit 12 in accordance with an optical coupling between the photocoupler 10b and the photocoupler 11b. In this combustion forced stop circuit 12, a threshold value V02 for determining the occurrence of an instantaneous power failure or an instantaneous voltage drop on the power supply side is set in advance.
If the applied voltage V2 is within a range that does not cause any problem compared to the threshold value V02, the power supply side is determined to be normal, and the switching element 14 is kept in the on state. on the other hand,
If the applied voltage V2 is in a problematic range as compared with the threshold value V02, it is determined that an instantaneous power failure or abnormal instantaneous voltage drop has occurred on the power supply side, the switching element 14 is turned off, and the power to the combustion unit 15 is reduced. The supply is cut off, and the operation of the combustion unit 15 is forcibly stopped.

As described above, in this embodiment, when an instantaneous power failure or instantaneous voltage drop occurs on the power supply side, the control unit 16 controls the combustion unit 15 based on a signal from the output voltage monitoring circuit 20 provided on the secondary side. To stop the combustion by instructing the power supply side, there is no need to provide a detection circuit for instantaneous power failure or instantaneous voltage drop, which is conventionally provided separately on the power supply side.
Therefore, the cost can be reduced and the circuit can be downsized.

Further, the forced combustion stop circuit 12 is provided so that, when an instantaneous power failure or an instantaneous voltage drop occurs on the power supply side, not only the combustion stop by the control unit 16 but also the forced combustion stop circuit 12 is operated at the same time. Thus, the combustion can be stopped more reliably, and the safety in the event of an abnormality can be further improved.

[0023]

Since the present invention has the above-described configuration,
The following effects can be obtained.

According to the first aspect of the present invention, when an instantaneous power failure or instantaneous voltage drop occurs on the power supply side, the combustion control means operates the combustion section based on an emergency signal from the output voltage monitoring means provided on the secondary side. To stop combustion by instructing the system to eliminate the need for a separate circuit for detecting instantaneous power failures or instantaneous voltage drops, which was previously provided separately on the power supply side, thus reducing costs and miniaturizing the circuit. can do. According to the second aspect of the present invention, the forced combustion stop means is provided, and when an instantaneous power failure or an instantaneous voltage drop occurs on the power supply side, not only the combustion stop by the combustion control means but also the forced combustion stop means is operated at the same time. As a result, the combustion can be stopped more reliably, and the safety in the event of an abnormality can be further improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a combustion control device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Combustion control device 2 Commercial AC power supply 3 Rectifier circuit 4 Smoothing capacitor 5 Switching power supply control unit 6 Transformer 8 Diode 9 Smoothing capacitor 10a Photocoupler 10b Photocoupler 10c Photocoupler 11a Photocoupler 11b Photocoupler 11c Photocoupler 12 Combustion forced stop circuit (Combustion forced stop means) 14 switching element 15 combustion unit 16 control unit (combustion control means) 18 resistance 19 resistance 20 output voltage monitoring circuit (output voltage monitoring means) 21 connection point 61 primary winding 62 secondary winding 63 iron core 621 Secondary winding

Claims (2)

[Claims] 1. A configuration is provided in which a voltage from a power supply is input to a primary side of a transformer, the primary voltage is switched by a switching power supply control section, and a secondary voltage obtained by the switching is supplied to a combustion section. A combustion control device, comprising: an output voltage monitoring unit that monitors the secondary voltage and outputs a monitoring signal according to the secondary voltage; and a combustion control unit that controls the combustion unit. The monitoring means outputs an emergency signal to the combustion control means in response to an instantaneous power failure in the power supply unit or a drop in secondary voltage due to an instantaneous voltage drop, and the combustion control means stops combustion in response to the emergency signal. A combustion control device. 2. A combustion forced stop means for instructing the combustion section to forcibly stop combustion, wherein the output voltage monitoring means includes a secondary voltage drop accompanying an instantaneous power failure or an instantaneous voltage drop in a power supply section. Receiving the emergency signal and outputting an emergency signal to the combustion control means and the forced combustion stop means, wherein the combustion control means and the forced combustion stop means stop the combustion in response to the emergency signal. The combustion control device according to any one of the preceding claims.