KR101230492B1 - System and method for controlling temperature in thermoelectric element evaluation apparatus - Google Patents

Abstract

PURPOSE: A temperature control system and a method of a thermoelement evaluating device are provided to obtain an average value of temperature sensed by a plurality of temperature sensors installed in the device and control the temperature of the device based on the average temperature value, thereby accurately controlling the temperature of the thermoelement evaluating device. CONSTITUTION: A temperature control system of a thermoelement evaluating device of a thermoelement elevating device comprises a plurality of hot plate temperature sensors, a plurality of cooling plate temperature sensors, a temperature information acquisition unit, an average temperature calculating member, and a temperature controller. The hot plate temperature sensors are installed inside a hot plate(210) where a hot heating wire(211) of the thermoelement elevating device. The cooling plate temperature sensor is spaced from the hot plate at a predetermined space and installed inside the cooling plate. The temperature information acquisition unit obtains temperature information by sensing the temperature of a hot plate and a cooling plate. [Reference numerals] (240) Temperature controller; (250) Temperature information acquisition unit; (260) Computer

Description

System and method for controlling temperature in thermoelectric element evaluation apparatus

The present invention relates to a temperature control system and method of a thermoelectric element evaluation apparatus, and more particularly, to obtain an average temperature using a plurality of temperature sensors in a thermoelectric element evaluation apparatus. System and method.

Thermoelectric devices are commonly referred to by various names as thermoelectric modules, Peltier devices, ThermoElectric Coolers (TEC), and ThermoElectric Modules (TEM). The thermoelectric element can be called a small heat pump. That is, it is a device that absorbs heat from a low temperature heat source and heats the high temperature heat source.

In principle, when a DC voltage is applied across the thermoelectric element, heat is transferred from the heat absorbing portion to the heat generating portion. Therefore, as time goes by, the temperature of the heat absorbing portion decreases and the temperature of the heat generating portion increases. At this time, if the polarity of the applied voltage is changed, the heat absorbing portion and the heat generating portion are changed to each other, and the flow of heat is reversed.

However, the figure of merit ZT of the thermoelectric element is determined by the thermal conductivity, the electrical conductivity, and the Seebeck voltage of the thermoelectric element. A structure for measuring double electrical conductivity and Seebeck voltage is shown in FIG. 1.

Referring to FIG. 1, as shown in the drawing, the thermoelectric characteristic measuring apparatus 100 is formed in a hermetic container 10 that can be maintained in a vacuum state by heating by the heating element 21. The other end of the sample 200 by a combination of the first heat source 20 capable of heating the end to a high temperature of 700 ° C. or more, for example, heating by the heating element 26 and cooling by the coolant 27. For example, a second heat source 25 capable of being heated and cooled from a low temperature below the liquid nitrogen temperature to a high temperature of 700 ° C. or more is provided. The sample 200 is sandwiched between both heat sources 20 and 25. Is supposed to be installed.

In addition, the thermoelectric characteristic measuring apparatus 100 operates the vacuum pump 40 for evacuating the inside of the airtight container 10, the vacuum gauge 41 for measuring the degree of vacuum in the airtight container 10, and the operation of the first heat source 20. The first temperature controller CTR1 for controlling, the second temperature controller CTR2 for controlling the operation of the second heat source 25, the air pump 45 for flowing the coolant 27, and the sample 120. An external power supply E for imparting a potential difference between both ends is provided.

In addition, the thermoelectric characteristic measuring apparatus 100 is a temperature measuring means for measuring the temperature of both ends of the sample 120, at least two pairs, in this embodiment, for example, three pairs of thermocouples TC1, TC2, TC3. Have The thermocouples TC1, TC2 and TC3 are drawn out of the airtight container 10 outside the container 10, and the thermocouples TC1, TC2 and TC3 are controlled by the first and second temperature controllers CTR1 and CTR2. do.

However, in the conventional method, even though there are a plurality of thermocouples TC1, TC2, and TC3, the temperature is applied as the set temperature. Therefore, since the power applied to the first heat source 20 and the second heat source 25 is also constant, there is a disadvantage that it is difficult to control the accurate temperature.

In other words, when there are a plurality of thermocouples TC1, TC2, and TC3, the temperature may be different for each measurement position. For example, the set temperature (Set Point) is 30 ℃, it can be 29 ℃, 29.6 ℃, 29.2 ℃ for each measurement position. Therefore, since the temperature is controlled only by the temperature measured at a specific point, it is difficult to accurately evaluate the performance index (ZT) of the thermoelectric device because the temperature control is not accurate.

That is, even if the average temperature of the first heat source 20 is not equal to the set temperature, the temperature of the place where the temperature sensor used as the input value of the temperature controllers CTR1 and CTR2 is located is unique (the temperature sensor value of the remaining portion). Even if there is much deviation between the set temperature and the set temperature, if it is equal to the set temperature, it is judged that the temperature control is correct and maintains the state without any further output adjustment. Therefore, the T _ave (average temperature) and T _set (set temperature) The phenomenon that the temperature deviation is large occurs.

Generally, when you want to control the temperature of a specific plate or object, there is no problem to control the temperature by using a temperature controller because one temperature sensor is attached and temperature is controlled. Since spatial temperature homogeneity is very important, precise temperature control is required.

In addition, the use of an AC power source has the disadvantage that it is inaccurate in calculating the thermal energy used to accurately control the temperature.

Japanese Laid-Open Patent Publication No. 07-324991

The present invention has been proposed in order to solve the problems according to the prior art, and an object thereof is to provide a system and method capable of accurate temperature control in a thermoelectric device evaluation apparatus.

It is another object of the present invention to provide a system and method for evaluating a precision figure of merit (ZT) of a precise thermoelectric element under accurate temperature control.

One embodiment of the present invention has been proposed to achieve the above object, and provides a temperature control system of the thermoelectric device evaluation apparatus. The temperature control system of the thermoelectric element evaluation apparatus includes: a plurality of hot plate temperature sensors installed in a hot plate configured with a hot hot wire of the thermoelectric element evaluation apparatus; A plurality of cooling plate temperature sensors spaced apart from the hot plate at predetermined intervals and installed in a cooling plate configured with a cooling hot wire; A temperature information acquisition unit for obtaining temperature information by sensing the hot plate and cooling plate temperatures from the hot plate temperature sensor and the cooling plate temperature sensor, respectively; Average temperature calculating means for averaging the temperature information to calculate an average temperature, and comparing the calculated average temperature with a preset set temperature to calculate a comparison difference value; And a temperature controller for applying additional power to the hot heating wire or the cooling heating wire by the calculated comparison difference value.

In addition, another embodiment of the present invention, the plurality of hot plate temperature sensor and the cooling plate temperature sensor is a temperature sensing step of sensing the temperature of the hot plate and the cooling plate is configured with the hot heating wire of the thermoelectric element evaluation device, respectively ; A temperature information obtaining step of obtaining, by a temperature information obtaining unit, sensed temperature information of the hot plate and the cooling plate from the hot plate temperature sensor and the cooling plate temperature sensor; A comparison difference value calculating step of calculating an average temperature by averaging the obtained temperature information by the average temperature calculating means and comparing the calculated average temperature with a predetermined set temperature; And an additional power applying step of applying additional power to the hot heating wire or the cooling heating wire by the temperature difference calculated by the temperature difference controller.

Here, the average temperature calculating means controls the output of the temperature controller until the deviation between the calculated average temperature and the predetermined set temperature and the standard deviation of the calculated average temperature for a predetermined time satisfy the set conditions. You can do

Here, the temperature controller may be characterized by using a direct current (DC) power source.

Here, the average temperature calculating means may be characterized by controlling the output of the temperature controller using a PID (Proportinal Integral Differential) control scheme.

According to the present invention, since the temperature sensed by a plurality of temperature sensors installed in the thermoelectric element evaluation apparatus is averaged to adjust the temperature of the thermoelectric element evaluation apparatus to an average temperature value, accurate temperature control is possible.

In addition, another effect of the present invention is that the temperature of the thermoelectric element evaluation apparatus is controlled by the average average temperature value, and thus it is possible to evaluate the performance index of the precise thermoelectric element.

1 is a block diagram showing a thermoelectric device evaluation apparatus according to the prior art.
2 is a configuration of the temperature control system of the thermoelectric element evaluation apparatus according to the present invention.
FIG. 3 is a diagram illustrating a temperature control of the hot plate 210 in FIG. 2.
4 is a diagram illustrating a temperature control of the cooling plate 220 in FIG. 2.
5 is a flowchart illustrating a process of controlling the temperature sensor in the thermoelectric device evaluation apparatus according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Hereinafter, a temperature control system and method of a thermoelectric device evaluation apparatus according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 is a configuration of the temperature control system of the thermoelectric element evaluation apparatus according to the present invention. 2, the temperature control system of the thermoelectric element evaluation apparatus 200 includes a thermoelectric element evaluation apparatus 200; A temperature information acquisition unit 240 for obtaining temperature information from the thermoelement evaluation apparatus 200; An average temperature calculating means (260) for calculating an average temperature by averaging the temperature information and comparing a calculated average temperature with a preset set temperature to calculate a comparison difference value; And it is configured to include a temperature controller 250 for adjusting the temperature of the thermoelectric element evaluation device 200 by applying an additional power by the calculated comparison difference value.

The thermoelectric element evaluation apparatus 200 has a structure in which a cooling tank 230, a cooling plate 220, a hot plate 210, and the like are layered. The structures of the thermoelectric element evaluation apparatus 200 will be described in detail below for easy understanding.

The cooling tank 230 serves to cool the heat transferred from the upper layer to an area for storing the cooling water 232. Here, the liquid nitrogen is usually used as the cooling water 232, but is not limited thereto, and liquid helium, freon gas, or the like may be used. In addition, the cooling tank 230 is provided with a water supply line 233 to inject or discharge the cooling water 232.

The buffer layer 231 is placed on the cooling tank 230. The buffer layer 231 serves as a buffer between the cooling tank 230 and the cooling plate 220, and a plate of a heat insulating material series may be used.

The cooling plate 220 is disposed on an upper end of the buffer layer 231, and a cooling plate temperature sensor 223 is installed at one side of the lower end of the cooling plate 220. Of course, the cooling heating wire 221 is arranged inside the cooling plate 220. The cooling heating wire 221 may be a type coated with Teflon on the outside, but is not limited thereto, and a general heating wire may be used.

In addition, the cooling plate 220 is made of an aluminum material excellent in heat transfer efficiency.

The hot plate 210 is configured at the upper end of the cooling plate 220. Similar to the structure of the cooling plate 220, the hot plate 210 has a hot hot wire 211 arranged therein. Along with this, the hot plate temperature sensor 213 is installed outward on one side of the lower end. The material of the hot plate 210 is made of metal. That is, for example, aluminum, copper and the like can be used.

Of course, the sample 120 is placed between the cooling plate 220 and the hot plate 210. In addition, a first ceramic plate 201 and a second ceramic plate 202 are formed between the sample 120, the cooling plate 220, and the hot plate 210, respectively. In other words, the first ceramic plate 201 is placed between the sample 120 and the hot plate 210, and the second ceramic plate 202 is placed between the sample 120 and the cooling plate 220.

This sample 120 becomes a thermoelectric element. Of course, the thermoelectric element is configured based on the thermoelectric phenomenon. Here, a thermoelectric element is a generic term of the element which can utilize the various effects shown by interaction of a heat and an electricity.

Examples of such thermoelectric devices include thermistors used for stabilization of circuits, detection of heat, power, and light, devices using the Seebeck effect for measuring temperature, and peltiers used in the manufacture of refrigerators and thermostats. ) And the like to utilize the effect. The most widely used material for thermoelectric elements is Bi ₂ Te ₃ .

The temperature information acquisition unit 240 is connected to the cooling plate temperature sensor 223 and / or the hot plate temperature sensor 213 to obtain temperature information of the cooling plate 220 and / or the hot plate 210. In detail, the cooling plate temperature sensor 223 and / or the hot plate temperature sensor 213 may acquire the temperature information sensed.

The computer 260 is provided with a microprocessor (not shown), a storage device (not shown), a program, software, a display (not shown), and the like as an average temperature calculating means. Accordingly, the computer 260 stores the sensed temperature information of the temperature sensors 213 and 223 in real time, and averages the temperature information to calculate an average temperature. In addition, a comparison difference value is calculated by comparing the calculated average temperature with a predetermined set temperature. As a method of controlling the temperature controller 250 by the computer 260, various control methods may be used. For example, the temperature may be controlled by using a PID (Proportinal Integral Differential) control method.

The temperature controller 250 serves to supply additional DC power to the thermoelectric device evaluation apparatus 200 by the comparison difference value calculated by the computer 260.

FIG. 3 is a diagram illustrating a temperature control of the hot plate 210 in FIG. 2. Referring to FIG. 3, five temperature sensors 213a to 213e are installed inside the hot plate 210. In other words, the first hot plate temperature sensor 213a, the second hot plate temperature sensor 213b, the third hot plate temperature sensor 213c, the fourth hot plate temperature sensor 213d and the fifth hot plate temperature sensor ( 213e is provided at regular intervals in the region of the hot hot wire 211 provided inside the hot plate 210. These five temperature sensors 213a to 213e are all connected to the temperature information acquisition unit 250.

4 is a diagram illustrating a temperature control of the cooling plate 220 in FIG. 2. 4 also has a configuration similar to FIG. Referring to FIG. 4, five temperature sensors 223a to 223e are installed inside the cooling plate 220. In other words, the first cooling plate temperature sensor 223a, the second cooling plate temperature sensor 223b, the third cooling plate temperature sensor 223c, the fourth cooling plate temperature sensor 223d and the fifth cooling plate temperature sensor ( 223e is installed at regular intervals inside the cooling plate 220. These five temperature sensors 223a to 223e are all connected to the temperature information acquisition unit 250. Of course, these five temperature sensors 223a to 223e are also provided at regular intervals in the region of the cooling hot wire 221 provided inside the cooling plate 220 similarly to FIG. 3.

5 is a flowchart illustrating a process of controlling the temperature sensor in the thermoelectric device evaluation apparatus according to an embodiment of the present invention. Referring to FIG. 5, the temperature is sensed using the hot plate temperature sensors 213a to 213e of FIG. 3 planted in each of the hot plates 210 of FIG. 3 (step S500). In other words, the temperature information acquisition unit 250 acquires the temperature sensed by the hot plate temperature sensors 213a to 213e.

The computer 260 reads the T1, T2, T3, T4, and T5 values from the temperature information acquisition unit 250 and calculates the average temperature T _avg (steps S510 and S520). In other words, the temperature values T1, T2, T3, T4, and T5 sensed by the temperature sensors 213a to 213e are read, and the average of these values is obtained. The average temperature is calculated by the following equation.

Here, n is the number of temperature sensors, and T _{1 ..} T _n represents the measured temperature value measured by each temperature sensor.

For example, when five hot plate temperature sensors 213a to 213e are used as shown in FIG. 3, the average temperature value is Tave = (T1 + T2 + T3 + T4 + T5) / 5.

When the average temperature is calculated, the computer 260 calculates a comparison difference value by comparing the set temperature T _{set, which} is the temperature set in the temperature controller 240 of FIG. 3, with the average temperature T _avg , and the temperature controller 240. ) And additional power is applied to the hot heating wire (211 of FIG. 3) by the comparison difference value calculated by controlling () (S530). In this case, the control method uses a PIC control method.

The computer 260 outputs the temperature controller (240 of FIG. 3) until the deviation between the set temperature T _set and the average temperature T _avg and the standard deviation of the average temperature Tab for a predetermined time satisfy the set conditions. By adjusting through the control, the spatial uniformity of the temperature in the hot plate 210 and the set temperature Tset are best controlled (steps S540 and 550).

Of course, the flow chart of Figure 5 described only the case of the hot plate 210, but similarly applies to the case of the cooling plate 220 shown in FIG.

120: sample 200: thermoelectric element evaluation device
210: hot plate 201: first ceramic plate
202: second ceramic plate 211: hot heating wire
213: hot plate temperature sensor
213a: first hot plate temperature sensor
213b: second hot plate temperature sensor
213c: third hot plate temperature sensor
213d: fourth hot plate temperature sensor
213e: fifth hot plate temperature sensor
220: cooling plate 221: cooling heating wire
223: cooling plate temperature sensor
223a: first cooling plate temperature sensor
223b: second cooling plate temperature sensor
223c: third cooling plate temperature sensor
223d: fourth cooling plate temperature sensor
223e: fifth cooling plate temperature sensor
230: cooling tank 231: buffer layer
240: temperature information acquisition unit
250: thermostat 260: computer

Claims (8)

A plurality of hot plate temperature sensors installed in a hot plate configured with a hot heating wire of the thermoelectric element evaluation device;
A plurality of cooling plate temperature sensors spaced apart from the hot plate at predetermined intervals and installed in a cooling plate configured with a cooling hot wire;
A temperature information acquisition unit for obtaining temperature information by sensing the hot plate and cooling plate temperatures from the hot plate temperature sensor and the cooling plate temperature sensor, respectively;
Average temperature calculating means for averaging the temperature information to calculate an average temperature, and comparing the calculated average temperature with a preset set temperature to calculate a comparison difference value; And
A temperature controller for applying additional power to the hot heating wire or the cooling heating wire by the calculated comparison difference value
Temperature control system of the thermoelectric element evaluation device comprising a.
The method of claim 1,
The average temperature calculating means,
Temperature control of the thermoelectric element evaluation device, characterized in that the output of the temperature controller is controlled until a deviation between the calculated average temperature and a predetermined set temperature and a standard deviation of the calculated average temperature for a predetermined time satisfy a set condition. system. 3. The method according to claim 1 or 2,
The temperature controller is a temperature control system of the thermoelectric element evaluation device, characterized in that using a direct current (DC) power.
3. The method according to claim 1 or 2,
The average temperature calculating means, the temperature control system of the thermoelectric element evaluation apparatus, characterized in that for controlling the output of the temperature controller using a PID (Proportinal Integral Differential) control system.
A temperature sensing step in which a plurality of hot plate temperature sensors and a cooling plate temperature sensor sense a temperature of a hot plate having a hot heating wire and a cooling plate having a cooling heating wire, respectively, of the thermoelectric element evaluation apparatus;
A temperature information obtaining step of obtaining, by a temperature information obtaining unit, sensed temperature information of the hot plate and the cooling plate from the hot plate temperature sensor and the cooling plate temperature sensor;
A comparison difference value calculating step of calculating an average temperature by averaging the obtained temperature information by the average temperature calculating means and comparing the calculated average temperature with a predetermined set temperature; And
An additional power supply step of applying additional power to the hot heating wire or the cooling heating wire by a temperature difference calculated by the temperature controller;
Temperature control method of the thermoelectric element evaluation device comprising a.
The method of claim 5, wherein
The average temperature calculating means,
The temperature control of the thermoelectric element evaluation device, characterized in that for controlling the output of the temperature controller until the deviation between the calculated average temperature and the predetermined set temperature and the standard deviation of the calculated average temperature for a predetermined time satisfies the set conditions. Way.
The method according to claim 5 or 6,
The temperature controller is a temperature control method of the thermoelectric element evaluation device, characterized in that using a direct current (DC) power.
The method according to claim 5 or 6,
And the average temperature calculating means controls the output of the temperature controller using a PID (Proportinal Integral Differential) control method.

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