JP2777746B2 - Combustor fan motor speed controller - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustor provided with a convection fan or a combustion fan, and more particularly to a control device for controlling the rotational speed capability of the fan motor.

2. Description of the Related Art Conventionally, the rotation speed of a fan motor of this type is controlled by turning off the phase of a power supply to lower the duty ratio.
No. 269821), or a wave removal control, so that several waves are always supplied and one wave is removed, and the wave removal control is performed repeatedly.

Problems to be Solved by the Invention However, among the above conventional methods, the phase control cuts the phase in order to lower the duty ratio, so the fan motor must be turned on at a high voltage, and is susceptible to noise, The phase width of the phase must be determined using a timer with high precision in terms of microcomputer software, and there is a disadvantage that programming becomes complicated.

Further, in the wave removal control, since one wave is removed when a certain number of waves are applied, for example, six waves are applied and 1
If it is a wave, the duty ratio is 6/7, but the duty ratio can only be limited to 2/3, 3/4, 4/5, 5/6, 6/7. And no fine control during that time.

Means for Solving the Problems The present invention has been made to solve the above-mentioned drawbacks, and has a commercial power supply zero volt cross detection circuit and a switching element (a phototriac in this example) for controlling a fan motor.
Then, one wave is energized first, and after that, the current energization rate is compared with the standard energization rate. If the current energization rate is less than the standard energization rate, the next one wave is energized. A microcomputer having a function of performing wave removal control such that the power is not supplied when the rate is higher than the reference power supply rate is provided, and the number of revolutions of the fan motor is controlled.

Operation In the present invention, a reference duty ratio is determined and compared with the current duty ratio to determine whether to energize or to remove the next waveform. Therefore, it is possible to control the reference duty ratio even if it is determined very finely.

Embodiment An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic circuit diagram of a combustor according to the present invention,
1 is a commercial power supply, 2-2 is a relay for controlling the ignition heater 6, 3 is a switching element (photo triac) for controlling a convection fan 7 for sending warm air into the room, 4 Reference numeral -2 denotes a switching element (photo triac) for controlling the combustion fan 8 for supplying combustion air, and reference numeral 5-2 denotes a relay for supplying power to the pump drive circuit 9. Are connected in parallel. Further, the pump driving circuit 9 includes a pump 10
And a circuit for supplying oil. A transformer 11 has a rectifying bridge diode 12 on its secondary side.
, And smoothing with the smoothing capacitor 14, and the relay 2-
1, 5-1 and a power supply to be supplied to the switching elements (photo triacs) 3-1 and 4-1.
Reference numeral 13 denotes a constant voltage regulator, which constitutes a power supply of the microcomputer 15. Reference numeral 16 denotes a room temperature detection circuit, which is a circuit for detecting the room temperature by a thermistor or the like.
When a signal is input to the microcomputer 15, the microcomputer 15 performs A / D conversion and detects the room temperature. 17, 18, 19 and 20 are drivers for the relays 2-1 and 5-1 and the phototriacs 3-1 and 4-1. Reference numerals 21 and 22 denote limiting resistors for limiting the current flowing to the diode side of the phototriac. Reference numeral 23 denotes a zero volt detection circuit for detecting a zero volt cross point of the commercial power supply 1.

Here, the basic operation of the combustor according to the present invention will be described. First, the combustion fan 8 is rotated to supply combustion air, and the ignition heater 6 is energized to drive the pump 10 to supply oil to form a flame.
Rotate to blow out warm air. Although not shown in FIG. 1, the set temperature can be set during combustion, and the combustion amount is switched from strong to slight combustion in consideration of the difference from the room temperature detected by the room temperature detection circuit 16. A signal is output from the microcomputer 15 to the pump drive circuit 9 for the oil amount, and the oil amount is changed accordingly. The convection fan 7 and the combustion fan 8 are composed of photo triacs 3 and 4.
The air volume is changed by changing the duty ratio of

In the present invention, as for the rotation speed control of the fan motors of the convection fan 7 and the combustion fan 8, the wave removal control is performed as shown in FIG. This is because the microcomputer 15 detects the signal from the zero volt detecting circuit 23 as shown in FIG. 2 (2) and the photo triacs 3-1, 3-2, 4 from the microcomputer 15 as shown in FIG. 2 (3). -1,
By extracting only one output to 4-2, the duty ratio to the phototriacs 3-1, 3-2, 4-1 and 4-2 is reduced, and the number of rotations is reduced.

If you want to achieve the desired number of rotations, set the duty ratio to, for example, 70.
%, It is sufficient to conduct 70 waves out of 100 waves and de-energize 30 waves. In this case, energize 70 waves continuously, then de-energize 30 waves continuously Then, as shown in the flowchart of FIG. 3, one-wave energization is performed first, and thereafter, the reference energization rate (in this example, 70/100) is compared with the current energization rate. To determine whether to energize or de-energize the next one wave. That is, when the first one wave is energized, the current energization rate is 1/1, and when comparing 1/1 and 70/100, 70/100 is smaller, so that the next one wave is not energized. And the current energization rate is halved by de-energizing, 70/100 compared to 70/100
Is larger, the next one wave is energized. As a result, the current energization rate becomes 2/3, and 70/100 is larger than 70/100, so the next energization is performed. And the current duty ratio is 3 /
It becomes 4, where 70/100 became smaller, and the next time it is de-energized. And the current duty ratio is 3/5, 70/100
The next is energized because it is larger. And the current duty ratio
4/6, 70/100 is larger, so the next will be energized. When the operation is performed up to 100 waves in this manner, the wave removal is performed almost evenly, and the duty ratio becomes 70%. The same calculation is performed again from the next one wave to 100 waves, and the calculation is repeated.

According to the present invention, it is possible to considerably control the rotation speed of the fan motor, and to simplify the control because a timer with high accuracy is not required in microcomputer software. Since it is a cross, there is an effect that noise is small. In this example, 100
Since the calculation is performed again from the beginning at the wave, the reference duty ratio can be set every 1% (for example, 70%).
%, 71%, 72%) and canceling every 1000 waves has the advantage that it can be set every 0.1% (for example, 70%, 70.1%, 70.2%).

[Brief description of the drawings]

FIG. 1 is a schematic circuit diagram of a combustor according to the present invention, and FIG. 2 shows a voltage between a fan motor, a zero volt detection waveform, and a microcomputer output diagram to a phototriac when control according to the present invention is performed. FIG. 3 shows a flowchart of one embodiment of the present invention. 3-1 and 3-2 are switching elements (photo triacs), 4-1 and 4-2 are switching elements (photo triacs), 7 is a convection fan, 8 is a combustion fan, and 15 is a combustion fan.
Is a microcomputer, and 23 is a zero volt cross circuit.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F23N 3/00-3/08 F23N 5/00

Claims (1)

(57) [Claims] 1. A combustor control device comprising a convection fan (7) or a combustion fan (8) for controlling the rotational speed capability of these fan motors, comprising: a commercial power supply zero volt cross detection circuit (23); The switching element for controlling the fan motor is first energized by one wave, and thereafter, the reference duty ratio and the current duty ratio are compared. If the current duty ratio is equal to or less than the reference duty ratio, the next 1 A microcomputer (15) having a function of performing wave removal control for energizing a wave and deenergizing the current energization rate when the current energization rate is greater than a reference energization rate;