JPS60169016A - Burning control device - Google Patents

Abstract

PURPOSE:To reduce the transient responce for rapid load variation by a method wherein a saturation preventive means is provided, and an output level of a proportional control means is maintanined under a setting volume condition when a detected temperature is varied for the setting temperature more than the designated value. CONSTITUTION:When an operation of a PID control means 1 is stopped momentarily by an output from a integrator AI as the output V of the PID control means 1 and by a transient response means 4, the open degree of a proportional valve 2 is compared with a reference electric voltage Valpha correspond to the previous setting supply value. A saturation preventive means 5 is provided, that is, when the output V is outputted exceeding the reference electric voltage Valpha, the output V from the integrator AI is fed back to the input side of the integrator AI for maintaining the output V under the reference electric voltage Valpha level without regard to the inputted electric voltage thereof. Thus, the saturation in the operation of the integrator AI can be prevented by said saturation preventive means. Thereby, the burning control device provided with a control means having a less transient response for rapid load variation can be obtained.

Description

[Detailed description of the invention] Zero launch #! J4 is a combustion control device that proportionally controls the combustion of combustion equipment. Specifically, in order to maintain the hot water temperature at a set temperature, the fuel supply amount is proportionally controlled based on the comparison result between the set temperature and the detected temperature. The combustion control device includes control means including at least integration means.

° Conventionally, in this type of combustion control device, the difference between the set temperature and the detected temperature is 11. Automatically adjusts the fuel supply amount, that is, the amount of heat supplied to the difference i1J
Increasingly, proportional control means capable of

The above-mentioned proportional control means can freely adjust the hot water temperature and perform stable temperature control without supplying unnecessary fuel. If this occurs, a transient response such as overshoot or undershoot will occur in the control, and by the time the control is stabilized, hot water will be dispensed at a temperature that is significantly different from the set temperature.There is no means to prevent this transient response. It was necessary.

As a means for preventing this kind of transient response, there is, for example, a combustion control device disclosed in Japanese Patent Publication No. 55-105710 (Japanese Unexamined Patent Publication No. 57-31722), but this means is not sufficient. There were some inconveniences as shown below.

That is, as shown in FIG. 7, the deviation between the reference voltage (Va') obtained by dividing the power supply voltage (VCC) by resistance and the output voltage (Vb') of the thermistor (RT') as a temperature detection means is calculated using an integrator. (Al') is calculated by the PID control circuit (1'), and the constant current drive circuit (
8′) is configured to control the drive current of
A voltage (V c' ) set a predetermined value lower than the reference voltage (Va'), that is, an overshoot base #1 voltage, is compared with the detection voltage (vb') to determine whether an overshoot has occurred due to a temperature change. An overshoot detection circuit (4') is provided.
), the manual level of the integrator (AI') is shifted, and the output (V') of the PID control circuit (1') is
By forcibly lowering the
is configured to be opened backward υ to the lowest opening that maintains combustion.

However, the overshoot detection circuit (4')
is to shift the integrator (AI') to a state where its output saturates to a lower limit value, thereby making it inactive;
And, the minimum opening degree of the proportional valve (2') is λ resistance (
PID control circuit (l') by R2') and '(Rgi)
Due to the fact that the operation is set to be indifferent, after overshoot occurs, the detection voltage (Vb') Al r4f
Even if the voltage exceeds the overshoot determination voltage (Vc'), there is a delay in the return of the PID control circuit (1') to the active state, resulting in the occurrence of a large overshoot shoot.

In other words, if the amount of hot water that comes out suddenly changes, there is a disadvantage that the hot water temperature fluctuates up and down with respect to the set temperature and it takes time for it to stabilize.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide a combustion control device equipped with a control means that exhibits less transient response to sudden load changes.

In order to achieve the above object, a combustion control device according to the present invention includes:
If the detected temperature differs from the set temperature by more than a predetermined value, the gtJ proportional control hand-to-palm membrane force is applied so that the fuel supply amount becomes a preset amount regardless of the detected temperature. The present invention is characterized in that it is provided with a saturation prevention means for controlling the level to maintain a predetermined amount of r++J.

The above configuration will be explained below based on the block diagram shown in FIG.

FIG. 1 is a block diagram of a combustion control device for adjusting the hot water temperature by proportionally controlling the amount of gas combusted, such as in a gas water heater. Detected temperature (tl and water temperature by □ RT)
f/n (Ij Proportional control as a means for adjusting the fuel supply amount by PID control means +11 equipped with an integrator (AI) based on the deviation from the set temperature (to) by the temperature setting means (VR) of Ij It is configured to proportionally control the opening degree of the valve (2).

Furthermore, the detected temperature (1) and the set temperature (to) are compared, and if the detected temperature (1) is greater than or equal to a predetermined value (αl) v4 with respect to the set temperature (to), a transient response is detected in the temperature control. When this occurrence is detected, the operation of the PID control means (1) is temporarily stopped, and a predetermined fuel supply amount (
Transient response detection means (4) controlled to maintain α2)
) is provided.

Then, the output of the integrator (AI), which is the output (V) of the 111D control means (1), and the transient response detection means (4)
) sets the opening degree of the proportional valve (2) in 110 in advance when the operation of the PID control means (11 is temporarily stopped) and sets the reference voltage (Va) corresponding to a constant supply amount. In comparison, when the output (V) exceeds this reference voltage (Va), the output (V) of the integrator (AI)
) to maintain the reference voltage (Va) regardless of its input terminal, the output (V) is fed back to the input side of the integrator (AI) so that the operation of the integrator (AI) does not saturate. A saturation prevention means (5) for controlling the button is provided.

In addition, 1 "1" (() As an anti-prevention film, -C is the fE #) pU of the integrator (AI), and the output (V
) to the predetermined amount (C2-), any configuration may be used, such as negative feedback means that prevents the output from exceeding a predetermined value or below the jjF constant value.

Due to the above structure, the following excellent effects have been achieved.

In other words, a transient response to load fluctuations such as overshoot may occur due to sudden driving of the hot water outlet, and PID fli
Even if the operation of the control means is temporarily stopped in a saturated operation state 1, the saturation prevention means prevents the P.I.D.I.
The output level of the Hjl1 means is maintained at a level corresponding to a predetermined supply amount set in advance, so that the output level of the Hjl1 means is not saturated. Therefore, the delay in operation when returning to the normal PID fltlJ control state is reduced, and the transient fluctuation of the temperature change can be minimized.

Hereinafter, specific embodiments of the present invention will be explained based on the drawings.

As shown in Figure 2, between the power supply (Vcc) and the ground point, there is a resistor (R1), (1), a two-mister (RT) as a temperature detection means, and a temperature setting means.
Connect the iJ resistor (VR) in series, and connect the power supply (
3 resistors (R8) between Vcc) and ground.

(R4), (R5) ft The detection voltage (Va) obtained from the connection point (A) of the two resistors (R1) and (R2) of the bridge circuit connected in series is passed through the buffer (AO) to the configuration described below. pH) is input to the control circuit 1@(1), and is also manually input to the comparator (A4) as the transient response detection means (4). On the other hand, the three resistors (R
8) '4 source side connection point of (R4) and (R5) (
B) The reference voltage (vb) obtained from the detection voltage (V
Comparison base No. 1 for a) (Tojite PID control circuit tl)
At the same time, input the reference voltage (Vc) obtained from the grounding point side connection point (C1) to the +jts d self comparator (A
4) is input as a comparison basis for overshoot detection.

-C, the voltage (V) corresponding to the deviation between the reference voltage (Vb) and the detected voltage (Va) is determined as a constant 'A m, which determines the bi degree of the proportional valve (2) that adjusts the fuel supply amount; + circuit (
3), and the reference voltage (V
c) The detected 1n pressure (Va) is discharged, that is,
The detected temperature (1) is set at a predetermined M(C) with respect to the set temperature (to).
1) Overshoot group 14LI7! degree (t
O'), the output voltage t of the comparator (A4) (DIK, hence the PID control circuit fl)
This is to forcibly lower v+ and control the proportional valve (2) in the direction of closing, thereby preventing the occurrence of overshoot.

The PID ID same-side circuit + includes six first operands (AI) constituting a differentiator, a second operand (A2) constituting an integrator (AI), and the following. Third operational term 11Vtl as saturation prevention means (6)
K4 (/M3), and the output E+ of the converter (A4) is connected to a diode (Di) and a resistor (R6).
) to the input of the integrator (A2), and when an overshoot is detected, the +Jr constant voltage corresponding to the resistor (R6) V is added to the input of the integrator (A2). By doing so, the level of the output of the PID suppressing circuit (1), that is, the output tv+ of the integrator (A2) is forcibly lowered.

Then, in order to prevent the operation of the integrator (A2) from becoming saturated due to the operation of the comparator (A4), the power supply (Vcc) is connected to the resistor (R7) by the amplification '/4 (A8) in step 11.
.

(R8) and the lower limit voltage (VL) corresponding to the minimum fuel supply amount which is the predetermined amount (C2) divided by the voltage divider (A
The deviation from the output ff) of 2) is amplified and the integrator (A2
) to the input side of the integrator (A2) by negative feedback via the input side F (D2), the output tv+ of the integrator (A2) is prevented from falling below the voltage (VL) regardless of the input level. Note that the diode (D2) is an integrator (
When the output ff+ of A2) is larger than the voltage (VL), U,+ is actuated to prevent feedback to the input terminal.

In addition, the constant current drive circuit (3
), but it may be omitted.

Moreover, FIG. 8 is a drawing in which the transient response of temperature when the flow rate changes is eliminated in the embodiment shown in FIG. 2, and 1i! ! : The response shown by the line shows the response when the saturation prevention means 511j is included in the KPID control means as in the conventional example.

Another embodiment will be described below with reference to the drawings.

As shown in FIG. 4, it has basically the same configuration as the embodiment shown in FIG. The differentiator (
By adding a predetermined voltage corresponding to the resistor (R6) to the input of A1), the circuit is configured to perform the same operation as the embodiment shown in FIG. still,
In the figure, the same reference numerals as in Fig. 2 and the subtraction of f6 indicate the same configuration or function as the embodiment shown in Fig. 2.

That is, since the polarity of No. 18 is reversed between the input of the differentiator (AI) and the input of the integrator (82), the VC and comparator (
In order to invert the -1 polarity of the output ρ) of 4), the polarity of the diode (Dl) of 6iJ is inverted and connected,
The reference voltage (
VC) and detection voltage (Va) are switched and connected.

Next, the saturation prevention means (5) was configured to detect both open neatness and undershoot, and to regulate both the upper and lower limits of the function #1 range of the fjIJ recording divider (AΣ). Another embodiment will be explained based on FIG.

That is, a comparator (
Along with A4), a resistor (, R8) is provided to detect undershoot.

(R8'), (R4), (R5) reference voltage for transient response determination (Vc), (VC
and the detection voltage (Va), and the resistor (R7').

The function of the integrator (82) set by (R7) and (R8)! An operational amplifier (A8') that provides negative feedback to the upper limit value (VH) of the fill range and an operational amplifier (88) that provides negative feedback to the lower limit value (VL) are provided. A8) Therefore, the output tv+ of the integrator (A2) is maintained at the lower limit value (VL) K, and when undershoot occurs, the output tv+ of the integrator (A2) is maintained at the lower limit value (VL).
J') V Therefore, the configuration is such that the output (Vl) of the integrator (A2) is maintained at the upper limit value (VH).

In addition, in order to adjust the gain of the PID control circuit tl) according to the meteor, as shown in Fig. 6,
I]iJ The resistor (RG) that determines the gain of the buffer circuit (AO) may be configured to have a flow rate height that changes the resistance ia in accordance with the flow rate.

In addition, the PID control circuit (1JfJ) is a differentiator (A1).
may be omitted and configured as a proportional control circuit using only the integrator (A2); similarly, the saturation prevention means ti)
Any device that can remix the amount of feedback, such as a pond using an amplifier, a resistor, or a Zener diode, may be used.

Alternatively, the control circuit or the entire combustion control device may be configured by a microcomputer, and the configuration can be modified in various ways.

[BRIEF DESCRIPTION OF THE DRAWINGS] 1cXJ is a block diagram showing the configuration of the combustion control device according to the present invention, FIG. 2 is a circuit block diagram showing the specific configuration of the combustion control device according to the present invention, and FIG. 8 is the eleventh work. 4 to 6 are circuit block diagrams of another embodiment, and FIG. 7 is a block diagram showing the configuration of a conventional example. +l)・・・Proportional system both means, (5)・・・・・・
Saturation prevention means, (AI), (Aj2)...
Integrating means, (tO)... Set temperature, (1)...
...Detected temperature, IV) ...Fuel supply amount, (
α1)...Predetermined value, (α2)...Predetermined amount, (VH)...Upper limit 11r1, (VL)...
····lower limit. Agent Patent Attorney Shukan Kitamura 1) 5j! No. 31 Hiro No. 7

Claims (1)

[Claims] ■ At least proportionally controlling the fuel supply fti: (V) based on the comparison result between the set temperature (to) and the detected temperature (11) in order to maintain the water temperature at the set temperature (to). The combustion control device is equipped with a control means il+ including an integrating means (AI), and if the detected temperature ([) in 1q differs from the set temperature (to) by a predetermined value (αl) or more, the detected temperature Regardless of (1), the output level of the proportional control means fi+ is adjusted so that the fuel supply ht (V) becomes a predetermined amount (α2) (F+fJ predetermined amount).
A combustion control device characterized in that it is provided with a flat anti-saturation membrane (5) for controlling the saturation to maintain the temperature. ■ The predetermined amount (α2) is the lower limit value (VL) of the fuel supply amount (V) necessary to maintain combustion and the fuel supply amount (V)
The combustion control device according to claim 0, wherein one or both of the upper limit values (vn) of . (2) The saturation prevention means (5) includes the integration means (At
) noh! [Special W characterized by regulating the iX range] [The combustion control device according to claims (1) to (2).