JPH06161569A - Temperature control method for cooling/heating enable element - Google Patents

Abstract

PURPOSE:To make possible stable temperature control, to reduce an overshoot amount, to shorten setting time and to improve the accuracy of temperature control by controlling heating/cooling sensitivity and making heating capacity and cooling capacity equal. CONSTITUTION:A temperature control system controls the heating and cooling of a controlled system 2 with a heating/cooling enable heat source element 1, and the cooling/heating enable element 1 has difference in the heating capacity and cooling. A temperature PV of the controlled system is measured by a measuring instrument 3, and the measured result is inputted to a subtracter 4 and a controller 5. The subtracter 4 calculates difference (e) between a set temperature SV and the measured temperature PV and inputs it to the controller 5. The controller 5 decides a manipulated variable Ce of the cooling/heating enable element 1 corresponding to the difference (e) and outputs it to a heating/cooling changeover switch 6. A cooling/heating switching signal SL is a switching signal to be decided corresponding to the positive/negative polarity of the difference (e) and it is decided whether the manipulated variable outputted from the controller 5 is outputted to an HG adjusting part 7 or to a CG adjusting part 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to temperature control of a temperature controller, and more particularly to a technique for improving temperature control performance for a heatable element having a difference in heating capacity and cooling capacity.

[0002]

2. Description of the Related Art Conventionally, PID control has often been used as a method for temperature control. In this PID control, a step response method, a limit cycle method, a limit cycle method, etc. are used when obtaining each constant (P, TI, TD). The above-mentioned constants that enable stable control as much as possible are obtained by the sensitivity method or the like.

[0003]

However, in the heatable element used for temperature control, such as a thermomodule,
Due to the effect of Joule heat, the heating capacity becomes larger than the cooling capacity. Therefore, the optimum temperature controllability cannot be obtained with the constants P, TI, TD obtained by the above-mentioned conventional method, and the temperature control becomes unstable. The overshoot amount to the heating side increases. However, problems such as an increase in settling time will occur as

The present invention has been made in view of the above circumstances, and by performing control to equalize the heating capacity and the cooling capacity, stable temperature control, reduction of overshoot amount, reduction of settling time, and temperature control are achieved. It is an object of the present invention to provide a temperature control method for a coolable element that achieves high accuracy.

[0005]

According to the present invention, in a temperature control method for a heatable element having a difference in heating capacity and a cooling ability, a temperature control method for a heatable element which cools and cools is performed in one cycle after a limit cycle is reached. The heating sensitivity and the cooling sensitivity are adjusted and controlled until the maximum value and the minimum value are equal and the heating time and the cooling time are equal, and then the cooling can be performed using the adjusted heating sensitivity and cooling sensitivity. It is characterized in that the element is controlled to be heated and cooled.

[0006]

According to the present invention, the heating capacity and the cooling capacity are made equal by adjusting the heating sensitivity and the cooling sensitivity prior to the ordinary temperature control of the PID or the like, and then the adjusted heating capacity is adjusted. Executes temperature control with sensitivity and cooling sensitivity.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings.

FIG. 1 shows an embodiment of the present invention.

The temperature control system of this embodiment controls heating and cooling of a controlled object 2 by a heat source element (coolable element) 1 capable of heating and cooling, and the coolable element 1 has a heating capacity as described above. There is a difference in cooling capacity.

The measuring device 3 measures the temperature PV of the controlled object,
The measured value PV is input to the subtraction point 4 and the controller 5.

The subtraction point 4 is the set temperature SV and the measured temperature PV.
And the difference e is calculated and input to the controller 5. The controller 5 determines the operation amount Ce of the coolable element 2 based on the difference e between the set temperature SV and the measured temperature PV, and outputs the operation amount Ce to the heating / cooling changeover switch 6. The controller 5 also outputs a heating / cooling switching signal SL to the heating / cooling switching switch 6. The heating / cooling switching signal SL is a switch switching signal of the heating / cooling switching switch 6 which is determined according to the positive / negative polarity of the difference signal e, and the operation amount output from the controller 5 by the heating / cooling switching signal SL. Ce is the HG adjustment unit 7 and the CG adjustment unit 8
To which of the following is output.

The HG (heating sensitivity) adjusting section 7 is driven when performing heating control, and outputs Ce · Gh obtained by multiplying the input operation amount Ce by the heat gain Gh to the heat source element 1. However, this heat gain Gh is obtained by multiplying the gain Ge (s) obtained by the PID control by the calculation unit 9 by the heating sensitivity HG (0 to 100%). The heating sensitivity HG is adjusted and controlled to an optimum value by the processing described later.

The CG (cooling sensitivity) adjusting section 8 is driven when performing cooling control, and outputs Ce · Gc obtained by multiplying the input operation amount Ce by the cool gain Gc to the heat source element 1. However, this cool gain Gc is obtained by multiplying the gain Ge (s) obtained by the PID control by the calculation unit 9 by the cooling sensitivity CG (0 to 100%). This cooling sensitivity CG is adjusted and controlled to an optimum value by the processing described later.

The controller 5 monitors the measured value PV after turning on the heat source element 1, and the controller 5 detects the time when the temperature of the controlled object 2 becomes stable from the measured value PV. Upon detecting the stable state, the controller 5 outputs a sensitivity adjustment control start signal ST for instructing to start the sensitivity adjustment control of the HG and CG adjustment units 7 and 8 to the calculation unit 9. The output time of the sensitivity adjustment control start signal ST is, for example, the time when the limit cycle is measured after the temperature of the controlled object 2 first reaches the set temperature SV after the control is started.

The calculation unit 9 obtains the gain Ge (s) of the PID control in accordance with the command of the controller 5, multiplies this by the heating sensitivity HG or the cooling sensitivity CG obtained by the sensitivity adjustment processing described later, and obtains them by multiplication. Heat gain Gh (= Ge (s) · HG) or cool gain Gc
(= Ge (s) · CG) is adjusted by the HG adjusting unit 7 or the CG adjusting unit 8
Output to.

FIG. 2 shows the sensitivity adjustment processing by the controller 5 and the calculation section 9. This flow chart will be described below with reference to the time chart of FIG.

When the heat source element 1 is turned on, the controller 5 first gives a command to the computing unit 9 so that the sensitivities of the HG adjusting unit 7 and the CG adjusting unit 8 become maximum values (HG = CG = 100%). As a result, the calculation unit 9 adjusts the HG adjustment unit 7 and the CG adjustment unit 8 so that the sensitivity becomes 100% at the maximum value.
The adjusting unit 7 and the CG adjusting unit 8 are adjusted (step 10).
0).

After that, when the system is stabilized and the limit cycle is measured by the controller 5 (initial limit cycle period in FIG. 3), the controller 5 outputs the adjustment control start signal ST to the arithmetic unit 9.

When the adjustment control is started, the calculation unit 9 executes ON-OFF control by the limit cycle (step 110). Further, the controller 5 measures the maximum value PVmax, the minimum value PVmin, the heating time Th, and the cooling time Tc of the measured value PV for each cycle (step 120, see FIG. 3).

Then, if | PVmax |> | PVmin | and Th <Tc (1), the controller 5 issues a command to the arithmetic unit 9 to decrease the heating sensitivity HG (or increase the cooling sensitivity CG). Output (steps 130 and 140).

If .vertline.PVmax.vertline. <. Vertline.PVmin.vertline. And Th> Tc (2), on the other hand, a command is output to the arithmetic unit 9 to increase the heating sensitivity HG (or decrease the cooling sensitivity CG). (Steps 150 and 160).

Then, such control is performed by | PVmax | = |
Repeatedly until PVmin | and Th = Tc.
Then, the heating sensitivity HG and the cooling sensitivity CG when | PVmax | = | PVmin | and Th = Tc are the sensitivity values used in the subsequent temperature control. In this way, the heating and cooling capacities of the heat source elements 1 having different heating and cooling capacities are made equal.

In the example of FIG. 3, since the above equation (1) is initially satisfied, the control for reducing the heating sensitivity HG is performed.

When the heating sensitivity HG and the cooling sensitivity CG are determined as described above (step 170), the arithmetic unit 9 uses the limit cycle method or the like to determine each constant value P (proportional gain) and TD (derivative) in the PID control. Time) and TI (integration time) are calculated by the following equation (step 180),
Further, the gain Ge (s) is obtained from these calculated values according to the following equation. In this case, the case of additional value control and the case of constant value control are shown.

<Additional value control> TD = 0.6T0 (3) TI = 0.1T0 <Constant value control> TD = 0.5T0 TI = 0.125T0 (4) where T0 = Th + Tc, α (duty) = Th / T0, and M is a manipulated variable limit.

[0026] Then, the calculation unit 9 obtains the gain Ge (s) thus obtained.
Is multiplied by the heating sensitivity HG and the cooling sensitivity CG previously obtained, respectively, and the heat gain Gh obtained by these multiplications is obtained.
(= HG ・ Ge (s)) and cool gain Gc (= CG ・ Ge)
(s)) is set in the HG adjusting unit 7 and the CG adjusting unit 8, respectively. Accordingly, when the heating control is performed, the product of the heat gain Gh and the manipulated variable Ce is applied from the HG adjusting unit 7 to the heating element 1, and when the cooling control is performed, the CG adjusting unit 8 cools the heating element 1 to the cool gain Gc. And the manipulated variable Ce are applied (step 190).

In FIG. 3, | PVmax | ≠ | PVmin | and Th ≠ Tc during the initial limit cycle, but the heating sensitivity HG and the cooling sensitivity CG in the sensitivity adjustment cycle.
As a result of the adjustment, the heating capacity and the cooling capacity become equal in the subsequent limit cycle with | PVmax | = | PVmin | and Th = Tc.

Although the present invention is applied to the PID control in the embodiment, the present invention may be applied to other PI and PD controls.

[0029]

As described above, according to the present invention,
In a temperature controller using a heat-coolable element capable of heating and cooling and having a difference between the heating capacity and the cooling capacity, the heating capacity and the cooling capacity are made equal by controlling the heating and cooling sensitivity. It is possible to realize stable temperature control, reduction of overshoot amount, reduction of settling time, and high accuracy of temperature control.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a flow chart showing the operation of the embodiment of the present invention.

FIG. 3 is a time chart showing the operation of the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Heat source element (element which can be cooled) 2 ... Control object 3 ... Measuring part 5 ... Controller 6 ... Heating / cooling changeover switch 7 ... HG adjusting part 8 ... CG adjusting part 9 ... Arithmetic part

Claims (1)

[Claims] 1. A temperature control method for a heatable element having a difference in heating capacity and a cooling capacity, which controls heating and cooling of a heatable element, wherein a maximum value and a minimum value of measured values in one cycle are reached after a limit cycle is reached. The heating and cooling sensitivities are adjusted and controlled until they are equal and the heating time and the cooling time are equal, and thereafter the heating and cooling control is performed using the adjusted heating and cooling sensitivities. A method for controlling temperature of a heatable element, comprising: