JPS62119322A - Method of controlling burner - Google Patents

Abstract

PURPOSE:To improve the followability of the control by obtaining a target control signal value from a difference between a detection temperature and a set temperature and making the maximum change width within a predetermined period of time variable by the quantity of combustion. CONSTITUTION:A voltage from a temperature detection circuit 1 is subjected to a proportional control P, a differentiation control D, and two-step differentiation control D<2> by means of a first control circuit 6, and a control voltage is output. Further, a second control circuit 7 outputs an integration control signal I, and is reversed by an arithmetic amplifier 8 and fed back to an output point A of the first control circuit 6 via the normal direction of a diode 11. The output of the second control circuit 7 is fed back to the output point A of the first control circuit 6 via the reverse direction of a diode 12. By this construction, the maximum variation width of the control signal value is varied on the basis of the quantity of combustion, and the quantity of combustion can be varied in the maximum width where no poor combustion is produced, thus improving the followability of the control.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to combustor control, and particularly to variable control of the combustion amount of a combustor using liquid fuel.

(b) Prior Art A conventional control method for a combustor using general VC liquid fuel is the one described in 'FF 1982-5S-79927.

This publication states that the temperature difference between the set temperature and the detected temperature (hot water temperature) is determined as an analog value, and this analog value is differentiated, integrated, and proportionally amplified using an operational amplifier to create a control code. The combustion t of the combustor was controlled by a signal.

P → Problem to be solved by the invention In a normal combustor, a constant air-fuel ratio O'' is required between the amount of fuel for combustion and the amount of air for combustion, and this air-fuel ratio can be significantly increased. When it comes off (for example, when fuel is over-supplied), poor combustion occurs and harmful substances such as carbon oxide are generated.

Therefore, when using liquid fuel, if conventional control methods are used, for example, when the load (water temperature) changes suddenly and greatly, the amount of fuel supplied to the combustor will also suddenly increase.
At this time, if the supply of air for combustion did not follow suit, there was a peak during which combustion failures as described above would occur.

On the other hand, in order to prevent the fuel supply amount from rapidly increasing (or decreasing), there is a system that sets a certain limit on the range of variation (hereinafter referred to as "change width") of the fuel supply amount within a certain period of time. Attempted. This variable ratio ratio differs depending on the combustion case, and the smaller the amount of combustion, the smaller the range of change needs to be. For this reason, it is necessary to set the maximum value of the variation range of combustion fuel supply in accordance with the minimum combustion amount, and if this maximum value is used to control the combustion amount, the problem is that it takes a long time to reach the target combustion amount. It was a new song.

In view of the above problems, the present invention focuses on the fact that the maximum allowable range of the fuel supply amount changes based on the combustion amount, and provides a combustor control method that can optimally change the fuel supply amount.

) between d point tj! :Means for solving the problem The present invention is a combustion t
In the combustion 4 control method, when the target control signal value is determined based on the temperature difference between the set temperature and the detected temperature, and the control signal 1 shift is changed from the current control signal value to the target control signal value. , the most frequent shift of the first shift of the control signal within a certain period of time is changed based on the combustion amount.

(g) Effect When using the controlling method of the present invention, it is possible to increase the amount of combustion while maintaining a predetermined air-fuel ratio, and even achieve the target combustion compared to the conventional method! 1Llc,! You can do it as fast as you like.

(F) Example Below, the embodiment of the present invention will be explained based on the drawings. First, 11th is an electrical circuit diagram of the main part used in the control method of the present invention, 1 is a temperature ejection circuit, and the detected temperature q Thermistor 2 to detect (61@), variable resistor 3 for setting the degree of stirring, resistor 4
, 5 are connected in a bridge shape. This temperature detection circuit 1
, the voltage based on the difference between the hot water and the set temperature (target control signal 1it)? It is output to the first control circuit 6. This first control circuit 6 includes a P antibacterial circuit that controls the voltage proportional to the voltage from the cropping rate detection circuit 1, and a D control circuit that similarly controls the differential D).
It consists of a D control circuit that controls the same dK second derivative (D).
, D, by D2 control, i! II output the 1st rejected item. (If integral control &l1ltl[l, this output corresponds to the output obtained by differentiating the output by P, 1.D control. In other words, there is a relationship of P, I, D2 fc D, P, D2). ) 7 is a second control circuit, which is comprised of a 1-control circuit that performs the above-mentioned integral (I) control.

The specific implementation circuits of these P control circuits, ■ control circuits, DlIJn circuits, and n2 control circuits can be constructed from well-known Nariko circuits using arithmetic operations, so a description of the circuit configuration and operation will be omitted. .

8 is amplification 4, and using resistor 9.10, the second system n
After inverting the output 1v) of the circuit T, it is fed back to the output black of the first damping circuit 6 via the negative direction of the diode 11. 12 is a diode, and the output of the second control circuit 7 (
Y) & is fed back to the output of the first control circuit 6 via the reverse direction of this diode.

A value M obtained by multiplying the output (v) of the second control circuit 7 by several times using the amplification 4 is used as the first control signal, and the amount of combustion fuel supplied is controlled based on this signal value.

Using the electric circuit diagram configured as shown above, the output of the first control circuit 6 increases and exceeds the value of the output tV), the diode 12 becomes conductive and the output voltage (control of the combustion amount The differential value of the signal (corresponding to the variation of the control signal) is limited by the output (v). On the other hand, when the output power of the first control circuit 6 is decreased and becomes less than 1 voltage of the output (-4), the diode 11 becomes conductive and limits the voltage of the output voltage to 1 voltage of the output (-V). do. Therefore, the voltage at the output point A is limited between -V and +vJ18, and this limit is proportional to the output 1 of the 21st μs circuit 7, that is, the voltage (7) of the control signal. It is something that changes.

To explain the specific operation using the present invention as described above, first, by changing the destination of the liquid fuel to be supplied,
When using a combustor in which the combustion t changes continuously between 2,000 and 10,0001 days/h, the maximum change in fuel supply amount must be determined so that combustion does not result in poor combustion. Therefore, the possible fuel supply amount at the minimum combustion time (combustion time of 2,000 days/h) is 2,000 kcal/second Xo, 2=
4007/h'js: Fuel to be obtained. Similarly 5,0
5.000kt#/h per second when burning at 00 to 21/A
Xo, 2 = fuel to obtain 1.000 d/h, 1,00
10,000 kt per second when burning at 0 CNral/h
*/h

In the conventional control method, the maximum variation width of the fuel supply amount was specified at the minimum fuel supply t (approximately 400kdZh of fuel per second), so for example, if the combustion amount was 2,000'
The time required to change the speed from ti/h to 10,000kc11/h was approximately 20 seconds as shown in Fig. 2.

On the other hand, in the controlling method of the present invention, the maximum variation range of the fuel supply amount can be changed based on the combustion sound at that time, so the combustion tVz, ooow/n to 10
, 000 days/h can be shortened to about 8 seconds, as shown by ■ in FIG.

(G) Effects of the Invention μAs described above, the present invention is a method for controlling a combustor that changes the combustor based on a control signal value, in which a target control signal 1 shift is determined based on the temperature difference between a set temperature and a detected temperature; When changing the control signal value from the current control signal value to the target control signal value, the maximum change width of this control signal value within a certain period of time is changed based on the combustion amount, so there is no possibility of combustion failure when changing the combustor. It is possible to change the combustion rate within the maximum range without causing the combustion amount change, and it is possible to control the combustion amount with good followability to changes in the amount of combustion.

[Brief explanation of drawings]

Figure 1 is a circuit diagram of essential parts showing an example using the method of the present invention, and Figure 2 shows a case where the electric circuit diagram shown in Figure 1 is used and a case where the conventional method is used. FIG. 1 is an explanatory diagram showing changes in combustion of 1...temperature detection circuit, 6...first control circuit, 7.
...Second control circuit, 8...Operation amplifier.

Claims (1)

[Claims] (1) In a combustor control method in which the combustion amount changes depending on the control signal value, the target control signal value is determined from the temperature difference between the set temperature and the detected temperature, and the control signal value is changed from the current control signal value to the target control signal value. A method for controlling a combustor, characterized in that the maximum change width of the control signal value within a certain period of time is changed based on the amount of combustion.