JPS62144211A - Temperature controller - Google Patents

Abstract

PURPOSE:To reduce the difference between the temperature to be controlled and the target temperature by providing a mechanism part to secure the thermal connection between a temperature sensor which detect the temperature of a control subject and the open air. CONSTITUTION:A control subject 11 is fixed to a cooling plate 12 and a contact is secured between the plate 12 and one side of a Peltier element 13. While a radiating fin 14 has a contact with the other side of the element 13. The element 13 is energized to heat and cool the subject 11. The subject 11 is shielded from heat by a heat insulator 15. Then the temperature of the subject 11 is detected by a temperature sensor 16 through the plate 12. At the same time, a heat connection part 17 is provided to the insulator 15 to secure the thermal connection between the open air and the sensor 16. Thus the detected temperature signal is supplied to a comparator 19 together with the setting signal given from a setting circuit 18. Then a current is supplied to the element 13 via a drive circuit 20 with the signal which is proportional to the difference between said temperature signal and setting signal. As a result, the coincidence is obtained between the genuine subject temperature and the target temperature by controlling the degree of connection at the part 17.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a temperature control device that can control the temperature of an object with high precision even when the outside temperature changes.

Prior Art The prior art is shown in FIG. Conventionally, a controlled object 1 whose temperature is to be controlled is sealed with a container 2 and a radiation fin 3, and the inside thereof is evacuated to remove the influence of outside temperature on the controlled object 1. The controlled object 1 is fixed to a cooling plate 4, and the temperature of the controlled object 1 is detected by a temperature sensor 5 attached to the cooling plate 4. A temperature signal corresponding to the temperature from the temperature sensor 5 and a setting signal from the setting circuit 6 are compared in a comparator circuit 7, and a signal corresponding to the difference between them is output. The drive circuit 8 outputs a current □ proportional to the signal from the comparison circuit 7, and the Peltier element 9 uses the current from the drive circuit 8 to heat or cool the cooling plate 4 and the controlled object 1, thereby adjusting the temperature of the controlled object 1. is set to a temperature corresponding to the setting signal from the setting circuit 6. The Peltier element 9 has two surfaces, and heat is carried from one surface to the other surface by passing an electric current, and as a result, one surface is cooled and the other surface is heated. For example, when cooling the controlled object 1, the surface of the Peltier element 9 on the radiation fin 3 side is heated, but by attaching the radiation fin 3, it is prevented from becoming high temperature.

As described above, in the conventional technology, the temperature of the controlled object 1 is set to the target value by controlling the surroundings of the controlled object 1 (Yamaro et al.: 1 Spectroscopic study of a semiconductor laser temperature control device using a Peltier element. Volume 32, Issue 6, P328 (1983)
).

Problems to be Solved by the Invention In the conventional technology, a current proportional to the difference between the temperature signal corresponding to the temperature of the controlled object from the temperature sensor and the setting signal from the setting circuit is passed through the Peltier element, and the temperature of the controlled object is proportionally changed. It's in control. Since proportional control is used, there is always an error between the temperature of the controlled object and the set temperature determined by the setting circuit, and this error increases as the difference between the outside temperature and the set temperature increases.

Therefore, in conventional devices, when the outside temperature changes, the temperature of the controlled object deviates from the set temperature and cannot be kept constant. However, if the ratio of proportional control is increased, the above-mentioned error can be made smaller, but at the same time, the control becomes unstable, so there is a limit to the method of reducing the error by increasing the ratio.

Means for Solving the Problems In order to solve the problems of the prior art as described above, the present invention provides a temperature sensor for detecting the temperature of a controlled object, a setting device for determining the target temperature, and a temperature sensor for determining the target temperature. A controller that outputs a current proportional to the difference between a temperature signal corresponding to the temperature of the controlled object and a set signal corresponding to the target temperature from the setting device, and a Peltier element that heats or cools the controlled object using the current from the controller. and a mechanism section that thermally couples the temperature sensor and the outside air.

Operation In the conventional technology, the temperature determined by the setting device (target temperature) and the temperature of the controlled object detected by the temperature sensor (target temperature) are compared, and a current proportional to the difference is caused to flow through the Peltier element.
Performs proportional control.

Since it is proportional control, the target temperature does not match the target temperature, and the target temperature deviates from the target temperature toward the outside temperature. In the present invention, since the temperature sensor and the outside air are thermally coupled,
A difference occurs between the temperature detected by the temperature sensor (detected temperature) and the temperature of the controlled object (true target temperature), and the detected temperature deviates from the true target temperature toward the outside temperature. Then, the detected temperature and the target temperature are compared, and proportional control is performed as in the prior art, but the detected temperature deviates from the target temperature toward the outside temperature.

The difference between the true target temperature and the detected temperature changes depending on the degree of thermal coupling between the temperature sensor and the outside air (degree of thermal coupling), and the difference between the target temperature and the detected temperature changes depending on the ratio of proportional control. By appropriately adjusting the degree of coupling and the ratio of proportional control, the true target temperature can be made to match the target temperature.

Example When trying to set the temperature of a controlled object (target temperature) to the target temperature by proportional control as in the conventional technology, an error occurs between the target temperature and the target temperature, and the difference between the outside temperature and the target temperature The larger the value, the larger the error (Figure 5)
. This error can be reduced by increasing the proportional control ratio, but if it is too large, the control becomes unstable, so there is a limit to how much the error can be reduced.

To remove errors caused by such proportional control, proportional/integral control or proportional/integral/derivative control can be used.
In the present invention, it is possible to reduce errors while using proportional control.

An embodiment of the present invention is shown in FIG. The controlled object 11 is fixed to a cooling plate 12 , the cooling plate 12 is in contact with one surface of a Peltier element 13 , and the radiation fin 14 is in contact with the other surface of the Peltier element 13 .

By passing current through the Peltier element 13 in this manner, the controlled object 11 can be heated or cooled through the cooling plate 12. The heat insulating material 16 is used to prevent heat from flowing into or out of the controlled object 11 and the like, thereby increasing the efficiency of heating or cooling by the Peltier element 13. The temperature of the controlled object 11 is determined by the cooling plate 1.
2 and is detected by the temperature sensor 16. Insulation material 15
A thermal coupling portion 17 is provided to thermally couple the outside air and the temperature sensor 16. A temperature signal corresponding to the temperature detected by the temperature sensor 16 (detected temperature) is input to the comparison circuit 19 together with a setting signal from the setting circuit 18 which determines the temperature (target temperature) as soon as the temperature of the controlled object 11 is set. Outputs a signal proportional to the difference between the temperature signal and the setting signal. The drive circuit 20 supplies a current proportional to the signal from the proportional circuit 19 to the Peltier element 13 .

In this way, the temperature detected by the temperature sensor 16 is controlled to match the target temperature determined by the setting circuit 18.

However, since proportional control is performed, the detected temperature and the target temperature do not match, and the detected temperature deviates from the target temperature toward the outside temperature side, as in the prior art.

By the way, in the present invention, since the temperature sensor 16 and the outside air are thermally coupled through the thermal coupling part 17, the temperature detected by the temperature sensor 16 and the temperature of the controlled object 11 (true object temperature) are different from each other. The target temperature deviates from the detected temperature to a temperature opposite to the outside air temperature, and the degree of thermal coupling of the thermal coupling part 17 (the amount of heat flowing into the temperature sensor from the outside or the amount of heat flowing out from the temperature sensor to the outside) is extremely high. If it is small,
Corresponding to the prior art, since the temperature detected by the temperature sensor 16 and the true target temperature are equal, if the proportional control ratio is increased in an attempt to match the true target temperature with the target temperature,
Operation becomes unstable.

As the degree of thermal coupling increases, the true target temperature shifts from the detected temperature to a temperature opposite to the outside air temperature, as described above. This deviation is determined by the degree of thermal coupling. Incidentally, since the proportional control is performed on the detected temperature, the deviation of the detected temperature from the target temperature is related to the outside temperature and the ratio of the proportional control, and does not depend on the degree of thermal coupling. Therefore, by adjusting the proportional control ratio to bring the detected temperature closer to the target temperature and at the same time adjusting the degree of thermal coupling, it is possible to make the true target temperature match the target temperature.

This will be explained in detail below using FIG. When the degree of thermal coupling is small (FIG. 2(a)), the deviation of the true target temperature from the detected temperature is small. As the outside temperature moves away from the target temperature, the detected temperature moves away from the target temperature as shown in the figure. In addition, the deviation of the true target temperature from the detected temperature must be small, so in order to set the true target temperature to the target temperature even if the outside temperature deviates from the target temperature, it is necessary to set the true target temperature to the target temperature using the proportional It is necessary to gradually increase the ratio of control.

Conversely, when the degree of coupling is large, the deviation of the true target temperature from the detected temperature is large. Therefore, contrary to the above case, even if the outside temperature deviates from the target temperature, in order to set the true target temperature to the target temperature, it is necessary to gradually reduce the proportional control ratio.

Therefore, if the degree of thermal coupling is selected to an appropriate value, the true target temperature will be maintained even if the outside temperature changes when the ratio of proportional control is kept constant (point D), as shown in Figure 2. can be set as the target temperature.

The above is a case where the outside temperature is higher than the target temperature.

Considering cases where the outside air temperature is higher or lower than the target temperature by the same amount, the deviations of the detected temperature and the true target temperature from the target temperature are equal (FIG. 2(C)). Therefore,
Even if the outside temperature is lower than the target temperature, if the ratio of thermal coupling degree and proportional control is set to the optimal value for the above-mentioned high case, the true target temperature will be set to the target temperature even if the outside temperature changes. be able to.

An embodiment of the thermal coupling portion 17 is shown in FIGS. 3 and 4. The thermal coupling part 16 has a cylindrical shape and consists of a heat transfer part 21 and a heat insulating part 22 as shown in FIG. 3, and is incorporated into the heat insulating material 15 and can be rotated as shown in the figure. The heat transfer part 21 is in close contact with the cooling plate 12, so that the temperature sensor 16 can be thermally coupled to the outside air through the cooling plate 12. The heat insulating section 22 serves to prevent unnecessary heat from entering and exiting. The contact area of the heat transfer part 21 with the cooling plate 12 can be changed by rotating it as shown in FIG. The degree of thermal coupling with outside air can be adjusted.

Effects of the Invention As mentioned above, even though the present invention uses a proportional control system with a simple configuration, even when the outside temperature changes,
It is possible to reduce the deviation of the temperature of the controlled object from the target temperature.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a temperature control device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of the operation of the same device, and FIGS. 3 and 4 are diagrams showing an embodiment of a thermal coupling part in the same device. FIG. 5 is an explanatory diagram of the operation of a conventional temperature control device, and FIG. 6 is a configuration diagram of the same device. 13... Peltier element, 16... group temperature sensor, 17... thermal coupling section, 18... old setting circuit, 1e... group comparison circuit, 20... ...Drive circuit. Name of agent: Patent attorney Toshio Nakao and one other person I!
? Cup of regret
1 Ward U) Castle

Claims (1)

[Claims] a temperature sensor that detects the temperature of a controlled object; a setting device that determines a target temperature; a controller that outputs a current proportional to the difference between signals from the temperature sensor and the setting device; A temperature control device comprising a Peltier element that heats or cools the controlled object, and a mechanism that thermally couples the temperature sensor to outside air.