JPS58213149A - Temperature-controlling method of hot water supplying device - Google Patents

Abstract

PURPOSE:To restrict an excessive rise in the temperature of tapped hot water even at the time of a rapid change in the amount of hot water and enhance temperature characteristic of tapped hot water, by controlling the amount of heat supplied to a hot water supplying device in accordance with the results of proportional, integrating and differentiating calculations of the difference between a set temperature and the temperature of tapped hot water. CONSTITUTION:In a control gain part 8 conducting a temperature control, the difference TER between a set temperature signal TWR and a supplied hot water temperature signal TWO2 generated by a tapped hot water temperature detector 10 fitted to a process 9 to be controlled is processed by proportional, integrating and differentiating calculating parts 11-13 to obtain outputs Vp, VTi and VTd. The smaller of the sum total TC of the outputs and a comparison output TM obtained from comparison between the output VTd and a predetermined value Vs is selected by a smaller value selector 16, and is given to the process 9. In this case, a predeter mined value multiplier 17 for the integrated value is further provided, and when the output VTd is changed by not less than a predetermined value, the integral amount is maintained at a value which is obtained therefrom by multiplying by a predetermined value according to the sign (plus or minus) of the differential amount, and the thus maintained value is used as an initial value in integrating operation when the output VTd is converged within a predetermined value.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control method for improving hot water outlet temperature characteristics in a water heater using gas, oil, electricity, etc. as a heat source.

Here, temperature control of an instantaneous feeder that uses gas as fuel will be explained as an example.

First, the configuration of the gas instantaneous water heater will be explained with reference to FIG. Combustion heat in a gas burner 1 serving as a heat source is replaced with water in a heat exchanger 2 to supply hot water.

The temperature controller 3 receives the signal T from the output/15 width degree detector 4.
WO and the signal TWR from the temperature setting device 6 are input, and a predetermined combustion range is determined based on the deviation TEI of the signal,
Supply heat limit mil't! 'j 6 is controlled and the hot water temperature T
Controlling WO. The number 7 comes out, and he is wearing a cloth.

Next, FIG. 4 shows the block configuration of the temperature control system. 8 is the control in the temperature control 1i11 device: Tq in the gain section
The following output is given to the target process 9 of ili'J1.

As a result, the hot water level TWO appears.

TVVO is T via the gain of the hot water temperature detection unit 1o.
Feedbank as WO271. I'm here. T to H
As shown above, 01 represents the deviation between the set temperature and the hot water temperature. It forms a feedback system.

Figure 6 shows the conventional temperature control method.
This is to stabilize the hot water temperature when sudden fluctuations occur. The deviation TER between the set temperature signal TVvR and the hot water supply temperature TWO2 via the hot water temperature detector is 11, 12.
It is processed by 13 proportional, integral, and differential calculation units, and the results are VP, respectively.

VTi and VTd are obtained. Here, the proportional gain is KP
, Integral time constant is Ti Differential time constant is Td1 Integral initial value is V
If Tiφ is used, the above results are shown as follows.

TER VTd=KP-Td, dt (3) The differential performance result VTd is calculated by the comparator 14 as a constant rc
When compared with vB at 7t, its output TM is vTd and reaches its maximum value at 1. When V T d > VS, it is fixed to the minimum value,
Input to selector 15. In addition, the above-mentioned proportional-integral-differential calculation result il T C of equation 1.2.3 is also input to the selector,
The smaller of TC and TM is controlled as the output Tq to process 9. The outlet hot water temperature TWO expressed via the process gain GP is fed back via the outlet hot water temperature detector.

FIG. 6 shows the response characteristics of each signal when the amount of hot water supplied suddenly changes using the conventional temperature control method. A knows the temperature of the hot water.

B is the differential calculator V 'I' d, C is the integral calculation amount V
Ti.

D shows the characteristics of the output Tq of the selector. When the hot water supply acid suddenly decreases at t=t1, the hot water temperature rises rapidly, and at 2 t2, the differential amount VTd is equal to the predetermined value vs-vTd.
Since the voltage exceeds M-, the output of the ratio reducer 14 becomes the minimum value (T
M=TCmin), selector 15 selects a low output value and Tg=
Give TCmin to the controlled process. In addition, at the time point 1 = 13 when VTd falls below VTdM- due to the subsequent change in the outlet hot water temperature, the comparator output takes the maximum value TCmax, so the output from the selector becomes Tq = TC, and the integral amount VT
It can be seen that i gradually decreases depending on the temperature deviation signal. “Furthermore, at 1 = 14, the dependence exceeds the predetermined value again, so the selector output becomes the minimum value. Also, at 1:15, due to the same phenomenon as t = 't, the selector output decreases. The fixation of is released and a value that depends on the proportional-integral-differential calculation result is output.The above operation suppresses the rapid decrease in hot water supply acid and the excessive temperature of the hot water at the outlet of I4, but the output value depends only on the differential value. A because the minimum value is fixed
It can be seen that the tap water temperature converges after undergoing an oscillating phenomenon like this. This large oscillation phenomenon in the water temperature causes the user of the water heater to directly expose his/her body to hot water. Especially when used as a shower, the discomfort was a major problem in terms of usability.

The present invention solves the above-mentioned conventional drawbacks, and even when there is a sudden change in the amount of hot water supplied, the hot water temperature does not exceed ( The purpose of the present invention is to provide a temperature control method for a water heater that suppresses as much as possible λ barshoot when hot water supply acid decreases and undershoot when it increases, eliminates vibration phenomena, and quickly approaches the set temperature.

In order to achieve the above object, the present invention includes a proportional/integral/differential calculator, a comparator with a predetermined 1i [716M table for the amount of differential calculation, and an integral amount according to the positive/negative of the differential calculator and the output of the comparator. an integral value predetermined multiplier that multiplies the value by a predetermined value to give an initial value to the integral calculator; a normal proportional-integral-differential calculated value or a change in the output of the comparator; and a selection that is selected depending on the sign or negative of the differential amount and is applied to the controlled process. It is equipped with a container as a component.

The temperature control method for a water heater according to the present invention will be described in detail along with its effects.

If there is a sudden change in the amount of hot water supplied, the hot water temperature will also fluctuate due to process delays, etc., resulting in hot water fluctuations. The differential value calculated in accordance with the rate of change in the outlet hot water temperature also changes rapidly, and when its absolute value changes by more than a predetermined value VTdM, the output signal of the comparator changes. and: At the same time, the integrated value is multiplied by a predetermined multiplier according to the change signal of the comparator output and the differential calculation amount [E negative]. , if the value is negative, the operation is decreased by 1 (not 7) and held. The selector selects the signal to be output as described above according to the change signal of the comparator output and the positive or negative value of the differential operator.In other words, when the positive differential amount exceeds a predetermined value, the signal to be output is The output is set to the maximum value, and conversely, when the negative differential amount exceeds a predetermined value, the minimum value is selected.

When the above-mentioned operation suppresses the excessive discharge temperature and the differential amount converges to below the predetermined value VTdM), the selector detects the change in the comparator output signal and releases the fixation of the output to the maximum and minimum values. In addition, the integral calculator starts the performance of the hot water discharge degree deviation by setting the value held by the above-mentioned integral predetermined multiplier as the first aid 111. By multiplying the integral value by a predetermined value in this way, it is possible to provide a supply heat amount that quickly corresponds to an increase or decrease in the amount of hot water supplied from the mrb hot water temperature change, and it is possible to accelerate the convergence of the hot water temperature.

According to FIG. 1, a specific configuration example of the temperature control method of the present invention is shown. Components with the same numbers as in FIG. 6 are components having similar functions. A selector 16 selects the proportional-integral-differential calculation result or the extreme value (maximum weight or minimum) according to the output of the differential calculator and outputs it as the amount of heat to be supplied. 17
is an integral value predetermined multiplier that operates as described above.

Next, according to FIG. 2, response characteristics of each signal according to the hot water temperature control method of the present invention when the amount of hot water supply decreases rapidly are shown. A
indicates the outlet temperature, B indicates the differential computing unit, C indicates the integral computing unit, and D indicates the characteristics of the selector output. As in Figure 5, 1=11
The hot water supply paper rapidly decreased at 1 == 12, and the differential amount exceeded the predetermined value VTdM- on the negative side, so the output to the process became the minimum value (Tq-T Qn i n ), and at the same time,
The integral calculation needle is multiplied by a predetermined value less than 1 and is held as V T i y. The differential amount − by the subsequent change in output/lJ width
At t = 13, when 1 is less than the predetermined value, the fixation of the minimum value of the output to the process is released, and at the same time, the integral M, which was held by multiplying it by a predetermined value as before, is set as the initial value. An integral calculation is performed, and the hot water temperature is then determined based on the result of the proportional-integral-differential calculation.

Since the performance value is 1 times larger than before the hot water supply fluctuation, as can be seen from A, Vc approaches the set width tg in a short period of time without a large oscillation phenomenon of the hot water outlet temperature.

In Figure 2, we took the case where the t and L hot water heaters decreased as an example.
Conversely, if J is added to JiQ, cl, positive differential 1ml is I9
7. During the period in which the selector output exceeds the fixed value ゛, the selector output is fixed at the maximum value, and the
The value is then held and set as the initial value, and the operation continues.

In this case as well, the undershoot of the tapped water temperature is suppressed, and the blackness converges to the set r without causing a large vibration phenomenon.

As explained above, the hot water supply area control method of the present invention
For example, even when there is a sudden change in the amount of hot water supplied, overextension in the hot water supply width range is greatly suppressed, and the temperature settles to the set temperature in a short period of time without the vibration phenomenon that occurs in conventional systems, improving usability.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the water heater control method of the present invention, and FIG. 2 is a block diagram showing the water heater control method of the invention.
Characteristic diagram of I3 differential quantity, C fraction, D selector 111 force, Fig. 3 is a block diagram of the gas water heater, Fig. 4 is a block diagram of the T blackness control system, and Fig. 5 is the conventional control. FIG. 6 is a block diagram showing the conventional t'JI +1lll method. 1.----Gas burner, 2...Heat exchanger, 3.
... Temperature controller, 4 ... Output water Va degree detector, 6 ... - Temperature setting device, 6 ... Supply heat amount controller, 7 ...・Spout. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3] ゛4 Figure 5

Claims (1)

[Claims] Based on the proportional-integral-differential calculation result of the deviation between the set temperature and the hot water temperature (TER), the amount of heat supplied to the water heater is calculated as
1ll + hot water temperature control method is used, and the absolute value of the differential amount due to the performance - is a predetermined value VT.
d, when the integral changes by a predetermined value corresponding to the negative iE of the differential amount, the integral is maintained at a predetermined value corresponding to the negative value of the differential amount, and the amount of heat supplied is fixed at a predetermined value corresponding to the positive or negative value of the differential amount, so that the temperature side n is performed, and when the absolute differential value converges within the 791 constant value VTdM, the fixation of the supplied heat 1 is released, and
The integral calculation is a temperature control method for a water heater in which the retained value is given as an initial value to control the amount of heat to be supplied.