Method for measuring characteristic parameters of semiconductor chilling plate

Abstract

The invention discloses a method for measuring characteristic parameters of a semiconductor chilling plate, and the method comprises the following steps: S1, electrifying, and measuring the hot end temperature and cold end temperature of the semiconductor chilling plate to be measured; s2, the temperature of the hot end is kept unchanged, the cold end is heated through a heater, and the temperature difference between the cold end and the hot end is zero; adjusting the heater to reduce the temperature of the cold end, and correspondingly measuring the heating power of the heater; powering off to raise the temperature of the cold end, and correspondingly measuring the electromotive force of the cold and hot ends; and S3, calculating a Seebeck coefficient and a resistance value of the to-be-tested semiconductor chilling plate, and calculating a heat conduction coefficient according to the Seebeck coefficient and the resistance value. According to the technical scheme provided by the invention, on the basis of lateral heating of the thin film heating resistor, the full temperature difference of the cold end and the hot end can be constructed only by heating and powering off the cold end, and the heating power is used for replacing the refrigeration power under the condition that the working current of the refrigeration sheet is not zero, so that the measurement process is simplified, the calculation error is reduced, and the measurement precision is improved.

Description

This application is a divisional application filed based on the contents of the embodiments of the specification of the original invention application "Multifunctional temperature control device based on semiconductor refrigeration chip". The application date of the original application is July 10, 2024, and the application number of the original application is 202410924026.9. Technical Field

[0001] The invention relates to the field of semiconductor refrigeration, and in particular to a method for measuring characteristic parameters of a semiconductor refrigeration sheet. Background Art

[0002] A semiconductor refrigerator is a PN junction made of special semiconductor materials. A thermocouple pair is formed through the PN junction. When direct current is connected, the thermocouple pair is cooled due to the Seebeck effect and the Peltier effect.

[0003] Compared with compression refrigeration or absorption refrigeration, semiconductor refrigeration chips have low requirements for the working environment, do not require refrigerants, and are quiet and vibration-free. In addition, by adjusting the working current of the semiconductor refrigeration chip, its cooling power output can be controlled. Therefore, semiconductor refrigeration chips are very suitable for applications with high temperature control requirements. The selection and characteristic parameter detection of semiconductor refrigeration chips are particularly important.

[0004] In the prior art, "Measurement and Selection of Characteristic Parameters of Semiconductor Refrigeration Components" in "Journal of Shanghai Jiaotong University" Vol.38, No.10, Oct.2004 proposed a method for measuring the characteristic parameters of semiconductor refrigeration chips, which uses a semiconductor refrigeration chip with known performance parameters to dissipate heat from the semiconductor refrigeration chip to be tested, so as to control the hot end temperature of the semiconductor refrigeration chip to be tested. The system has a complex structure, high cost and single performance. Summary of the invention

[0005] Based on this, the technical solution provided by the present invention uses a heater to control the cold end temperature of the semiconductor refrigerator under the condition that the hot end temperature of the semiconductor refrigerator remains unchanged. That is, through simple heater operation, the characteristic parameters of the semiconductor refrigerator are measured under different hot and cold end temperature differences. Not only does it not need to use complex peripheral refrigeration equipment, but it can also avoid the problem of frequent power on and off during the measurement process.

[0006] In order to achieve the above-mentioned object, the present invention provides a method for measuring characteristic parameters of a semiconductor refrigeration chip, the method comprising the following steps: S1: setting a working current, energizing the semiconductor refrigeration chip to be tested, and measuring the hot end temperature and the cold end temperature of the semiconductor refrigeration chip to be tested in a steady state; S2: keeping the hot end temperature unchanged, heating the cold end of the semiconductor refrigeration chip to be tested based on a heater so that the temperature difference between the hot and cold ends is zero; adjusting the heater so that the temperature of the cold end drops to a target temperature, and correspondingly measuring the heating power of the heater; the target temperature includes a sequence of temperature values ​​that are less than the hot end temperature and greater than the cold end temperature; powering off the semiconductor refrigeration chip to be tested, so that the temperature of the cold end rises to the target temperature, and correspondingly measuring the electromotive force between the cold end and the hot end; S3: calculating the Seebeck coefficient and the resistance value of the semiconductor refrigeration chip to be tested; S4: calculating the thermal conductivity coefficient of the semiconductor refrigeration chip to be tested according to a first formula, the first formula being specifically: Wherein, K is the thermal conductivity, α is the Seebeck coefficient, I is the working current, T c is a temperature value of the target temperature, T h is the hot end temperature, R x is the resistance value, and P is the heating power.

[0007] Specifically, the step of calculating the Seebeck coefficient of the semiconductor refrigeration piece to be tested includes calculating the Seebeck coefficient according to a second formula, and the second formula is specifically: α=U / (T h 'T c ), Wherein, U is the electromotive force.

[0008] Specifically, the step of calculating the resistance value of the semiconductor refrigeration plate to be tested includes calculating the resistance value according to a third formula, and the third formula is specifically: Among them, R x is the resistance value.

[0009] Preferably, in step S2, the step of maintaining the hot end temperature constant includes dissipating heat from the hot end of the semiconductor refrigeration plate to be tested based on the heat sink so that the hot end temperature is constantly equal to the ambient temperature.

[0010] Preferably, the step of heating the cold end of the semiconductor refrigeration chip to be tested based on the heater includes placing the heating surface of the heater in close contact with the cold end of the semiconductor refrigeration chip to be tested, and heating the heating surface through a thin film heating resistor.

[0011] Preferably, the method further comprises setting different operating currents, repeating steps S1-S4, To obtain the thermal conductivity coefficient of the semiconductor refrigeration plate to be tested under different working currents.

[0012] Furthermore, the method for calculating the resistance value includes a double-arm bridge method.

[0013] Furthermore, the step S3 also includes calculating the Peltier coefficient and the refrigeration efficiency.

[0014] The beneficial effects achieved by the present invention through the above technical solution are:

[0015] 1) By turning the semiconductor cooling chip on and off once, the different hot and cold temperatures under the current can be obtained. The characteristic parameters of the semiconductor refrigeration chip when the end temperature difference is large simplify the measurement operation and avoid the shortening of the service life of the semiconductor refrigeration chip caused by frequent power on and off.

[0016] 2) The temperature difference between the hot end and the cold end is controlled by heating the hot end at a constant temperature, which reduces the measurement The complexity of temperature difference control in the characteristic parameters of semiconductor refrigerators.

[0017] 3) When the power is on, the cooling power is replaced by the heating power under different temperature difference conditions to simplify the process. Improve measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the exploded structure of the temperature control device according to an embodiment of the present invention;

[0019] Figure 2 is a schematic cross-sectional structure diagram of a temperature control device according to an embodiment of the present invention;

[0020] Figure 3 is a circuit structure principle diagram of a control module according to an embodiment of the present invention;

[0021] Figure 4 It is a flow chart of a method for measuring characteristic parameters of a semiconductor refrigeration sheet according to an embodiment of the present invention;

[0022] Figure 5 The circuit structure of the embodiment of the present invention using the double-arm bridge method to measure the resistance of the semiconductor refrigeration piece Schematic diagram;

[0023] Figure 6 The graph of the cooling power of the semiconductor refrigeration sheet according to the embodiment of the present invention as a function of temperature and current is shown in FIG. Line chart;

[0024] Figure 7The graph of the cooling coefficient of the semiconductor refrigeration sheet according to the embodiment of the present invention as a function of temperature and current is shown in FIG. Line graph.

[0025] The symbols in the figure represent:

[0026] 1. Shell; 101. Opening; 102. Heat dissipation hole; 2. Constant temperature module; 21. Insulation rubber ring; 22. Sample chamber; 221. First sample chamber; 222. Second sample chamber; 3. Heat dissipation module; 31. Cooling plate; 32. Radiator; 4. Semiconductor refrigeration plate; 5. Thin film heating resistor; 6. Insulation cotton; 7. Connecting plate; 71. Through hole; 8. Cold end temperature probe; 9. Hot end temperature probe; 10. Sample temperature probe; 11. Connecting pin. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the following embodiments are described in detail. The specific embodiments of the present invention are further described in detail. It should be understood that the embodiments described herein are only used to explain the present invention, but are not used to limit the scope of the present invention.

[0028] Embodiment 1

[0029] Please see attached Figure 1 and attached Figure 2 , Figure 1 The exploded structure of the temperature control device according to the embodiment of the present invention is shown in FIG. intention, Figure 2 It is a schematic diagram of the cross-sectional structure of the temperature control device of the embodiment of the present invention. As can be seen from the figure, the multifunctional temperature control device based on the semiconductor refrigeration plate 4 provided in the embodiment of the present invention has the dual functions of measuring the characteristic parameters of the semiconductor refrigeration plate 4 and detecting the low-temperature performance of the sample. The temperature control device includes a control module, a shell 1, a constant temperature module 2 and a heat dissipation module 3. The control module is used to measure and control system parameters, and calculate characteristic parameters according to the system parameters, and the system parameters include temperature, voltage and current. The constant temperature module 2 and the heat dissipation module 3 are placed on the shell 1. An opening 101 is set at the top of the shell 1 for taking and placing the sample to be tested.

[0030] The constant temperature module 2 includes a sample chamber 22, a thin film heating resistor 5 and a semiconductor cooling sheet 4. The thermal resistor 5 is coated on the side of the sample chamber 22, and the cold end of the semiconductor refrigeration sheet 4 is close to the conduction part of the sample chamber 22. The conduction part of the sample chamber 22 is connected to the side of the sample chamber 22, and both are made of heat conductive material. The sample chamber 22 includes at least one sample cavity for storing the sample to be tested, and the opening of the sample cavity is consistent with the direction of the opening 101 of the shell 1. In an embodiment of the present invention, the sample chamber 22 is provided with a plurality of sample cavities, including a first sample cavity 221 and a second sample cavity 222 surrounding the first sample cavity 221, and a plurality of different samples to be tested can be placed at the same time. Among them, the inner diameter of the first sample cavity 221 is larger than the inner diameter of the second sample cavity 222. In other embodiments of the present invention, the distribution of the sample cavities can be in other forms, and the inner diameters of the sample cavities can have other size relationships.

[0031] In particular, the conductive portion of the sample chamber 22 is connected to the sample cavity for transmitting cold energy into the sample cavity.

[0032] In particular, both the cold end and the hot end of the semiconductor refrigeration sheet 4 are coated with thermal grease to facilitate heat conduction.

[0033] The thin film heating resistor 5 and the semiconductor cooling sheet 4 work together to adjust the temperature in the sample chamber 22. The thin film heating resistor 5 improves the tightness of the package, and the heating method is overall surface heating. Compared with other single-point heating methods using power resistors, it better ensures the uniformity of heating and allows the sample to be tested to reach a temperature steady state faster. In an embodiment of the present invention, the conduction part of the sample chamber 22 is arranged at the bottom of the sample cavity. In other embodiments of the present invention, the conduction part of the sample chamber 22 can be arranged at the top or other parts of the sample cavity.

[0034] The heat dissipation module 3 includes a cooling plate 31, and the hot end of the semiconductor cooling plate 4 is in close contact with the cooling plate 31. The thermal module 3 further includes a heat sink 32, which is fixed to the side of the cooling fin 31. In the embodiment of the present invention, the heat sink 32 is a cooling fan, and the housing 1 corresponding to the cooling fan is provided with cooling holes 102. In other embodiments of the present invention, the heat sink 32 can be other devices that can dissipate the heat on the cooling fin 31 and can adjust and control the heat dissipation speed.

[0035] The temperature control device further comprises a connecting plate 7 , which is fixed to the top of the housing 1 via a connecting pin 11 .

[0036] The connecting plate 7 has a first surface and a second surface opposite to the first surface, and the sample chamber 22 is connected The first surface, the cooling plate 31 is fixedly connected to the second surface. The connecting plate 7 is provided with a through hole 71 connecting the first surface and the second surface, the conducting part of the sample chamber 22 corresponds to the through hole 71, and the semiconductor cooling plate 4 is arranged in the through hole 71. The first surface of the connecting plate 7 is also provided with a heat-insulating rubber ring 21, the sample chamber 22 is placed in the heat-insulating rubber ring 21, and the outer side of the thin film heating resistor 5 and the inner side of the heat-insulating rubber ring 21 are filled with heat-insulating cotton 6. In the embodiment of the present invention, the heat-insulating rubber ring 21 and the connecting plate 7 are integrated, which not only enhances the heat-insulating effect of the sample chamber 22 but also fixes the sample chamber 22. In other embodiments of the present invention, the heat-insulating rubber ring 21 and the connecting plate 7 are separable.

[0037] Embodiment 2

[0038] Please refer to the attached Figure 3 , Figure 3 FIG. 1 is a schematic diagram of the circuit structure of a control module according to an embodiment of the present invention. The control module of the temperature control device disclosed in the embodiment of the invention is used to control the entire temperature control device to perform low temperature detection and measure characteristic parameters. The control module includes an onboard computer, a temperature control unit and a single-chip microcomputer. The temperature control unit is connected to a temperature probe, and the temperature probe includes a hot end temperature probe 9, a cold end temperature probe 8 and a sample temperature probe 10. The hot end temperature probe 9 is arranged at the hot end of the semiconductor refrigeration sheet 4, and the cold end temperature probe 8 is arranged at the cold end of the semiconductor refrigeration sheet 4. The sample temperature probe 10 is arranged in the sample cavity. According to the temperature control device of the first embodiment of the present invention, there can be multiple sample temperature probes 10, each of which is arranged in a different sample cavity. The single-chip microcomputer is connected to the semiconductor refrigeration sheet 4, and the single-chip microcomputer is connected to the thin film heating resistor 5. The onboard computer is used to control the temperature control unit and the single-chip microcomputer, and is used to receive and process data collected by the temperature control unit and the single-chip microcomputer. The temperature control unit is used to collect temperature data of the temperature probe and transmit the temperature data to the onboard computer. The single-chip microcomputer is used to collect electrical data of the semiconductor refrigeration sheet 4. The single-chip microcomputer is used to collect electrical data of the thin film heating resistor 5. The electrical data includes voltage and current. In the embodiment of the present invention, the onboard computer is equipped with a 64-bit Windows 7 system, is connected to the temperature control unit through a universal RS232 standard interface, and is connected to the single-chip microcomputer through an RS232 to TTL interface. The running main program can collect, display, and store temperature data in real time, and provide a PID (Propotional-Integral-Derivative) temperature control parameter adjustment window.

[0039] The single chip microcomputer used in the embodiment of the present invention is an Arduino single chip microcomputer. The single chip microcomputer is connected to the first current sensor. The first current sensor is used to measure the working current of the thin film heating resistor 5. The second current sensor is used to measure the working current of the semiconductor cooling piece 4. The voltmeter is used to measure the working voltage of the semiconductor cooling piece 4.

[0040] The control module also includes a constant DC power supply and an adjustable DC power supply. The computer, the temperature control unit, and the single-chip microcomputer are electrically connected to supply power to the temperature control unit, the onboard computer, and the single-chip microcomputer. The adjustable DC power supply is electrically connected to the semiconductor cooling sheet 4 and the thin-film heating resistor 5 to supply power to the semiconductor cooling sheet 4 and the thin-film heating resistor 5.

[0041] Embodiment 3

[0042] Please see attached Figure 4 , Figure 4 A method for measuring characteristic parameters of a semiconductor refrigeration sheet according to an embodiment of the present invention As shown in the figure, the method includes the following steps:

[0043] S1: Measure the Peltier coefficient. The specific steps are:

[0044] S11: Power on the semiconductor cooling chip 4. When the cold end temperature reaches the preset temperature, measure the cold end temperature. Degree T c and hot end temperature T h ;

[0045] S12: Disconnect the power supply of the semiconductor cooling plate 4, and make the current reading of the second current sensor zero. Immediately measure the electromotive force U between the cold end and the hot end of the semiconductor refrigeration plate 4; the measured electromotive force The cold and hot end temperatures corresponding to U are approximately the temperature values ​​obtained in step S11;

[0046] S13: Adjust the heating power of the thin film heating resistor 5 and the cooling power of the semiconductor cooling plate 4, Repeat steps S11 and S12 to measure the electromotive force U of the semiconductor cooling plate 4 when the current is zero under multiple groups of different temperature differences. According to formula (1): U=α(T h 'T c )+IR x , (1) Calculation of the Peltier coefficient π by fitting method Where α is the Seebeck coefficient.

[0047] S2: Measure the resistance value of semiconductor cooling sheet 4 at different temperature differences:

[0048] S21: Pass different currents to both ends of the semiconductor refrigeration sheet 4 to be tested, and adjust the film heating resistance 5 heating power, controlling the temperature difference between the hot end and the cold end of the semiconductor refrigeration piece 4 to be tested;

[0049] S22: Measure the temperature T of the cold end c and hot end temperature T h ;

[0050] S23: Keep the temperature difference between the cold end and the hot end of the semiconductor refrigeration piece 4 unchanged, and measure the temperature of the semiconductor refrigeration piece 4. The electromotive force U and current I between the cold end and the hot end;

[0051] S24: Calculate the resistance value R of the semiconductor refrigeration plate 4 to be tested at different temperature differences using formula (1) x

[0052] In the embodiment of the present invention, the characteristic that the resistance value of the semiconductor cooling sheet 4 changes with temperature is ignored. The resistance value of the semiconductor cooling sheet 4 is independently measured using the bridge method. Figure 5 , Figure 5 This is a circuit structure schematic diagram of the embodiment of the present invention for measuring the resistance of the semiconductor refrigeration chip 4 using the double-arm bridge method. Keep the temperature of the cold end and the hot end unchanged. When measuring, connect the semiconductor refrigeration chip 4 to the circuit and adjust R N , calculate the resistance R of the semiconductor refrigeration plate 4 when the bridge is balanced x .

[0053] S3: Measure the thermal conductivity K of the semiconductor cooling plate 4. Specifically: According to the cooling capacity formula Q L =αIT c 'I 2 R x / 2′K(T h 'T c ), (4) Among them, Q L is the cooling power.

[0054] Method 1: Set the current I of the semiconductor cooling plate 4 to zero, and measure the hot and cold end temperatures and the cooling power Q L , the thermal conductivity K can be calculated.

[0055] Method 2: The thermal conductivity coefficient K is a physical quantity that changes with temperature, but when the parts of an object When the temperature difference is not large, it can be regarded as a quantity that does not change with temperature. In the embodiment of the present invention, the physical parameters corresponding to the cooling power being zero can be known through the fitting curve of the Peltier coefficient.

[0056] The cooling power Q L = 0, and set the temperature control equipment for each parameter, and measure the semiconductor to be tested. The heat transfer coefficient is calculated based on the measured Seebeck coefficient and formula (2) of the hot end temperature, cold end temperature, working current and resistance of the cold plate 4.

[0057] Method 3: Keep the hot end temperature of the semiconductor refrigeration plate 4 to be tested constant with the ambient temperature. The thin film heating resistor 5 heats the cold end of the semiconductor refrigeration piece 4 to be tested, so that the cold end temperature of the semiconductor refrigeration piece 4 to be tested is the same as the hot end temperature, which is also equal to the ambient temperature. At this time, the cold and hot ends reach thermal equilibrium, and the working power of the thin film heating resistor 5 is equal to the cooling power Q of the semiconductor refrigeration piece 4 to be tested. L , and then use formula (4) to calculate the thermal conductivity coefficient K.

[0058] Plotting the cooling power Q of the semiconductor refrigeration plate 4 under different temperature differences L With the change of working current I The specific steps are:

[0059] S31: Use the thin film heating resistor 5 to heat the cold end of the semiconductor refrigeration piece 4 to make the cold end End temperature T c and hot end temperature T h same;

[0060] S32: After the system is thermally balanced, measure the temperature of the semiconductor cooling plate 4 to be tested at ΔT = T h 'T c =0 The relevant parameters under the condition include working current, voltage, cold end or hot end temperature, Heating power of the membrane heating resistor 5;

[0061] S33: Increase the working current of the semiconductor refrigeration plate 4 to be tested, repeat steps S31 and S32, and obtain Related parameters of different operating currents at the same temperature;

[0062] S34: Increase the target temperature of the thin film heating resistor 5, and repeat steps S31 to S33; This step is stopped when the cooling power of the conductive cooling sheet 4 or the heating power of the thin film heating resistor 5 is zero.

[0063] According to the above steps, the embodiment of the present invention obtains the following Figure 6 and attached Figure 7 The curve diagram of Figure 6 The graph of the cooling power of the semiconductor refrigeration sheet 4 according to the embodiment of the present invention as a function of temperature and current is shown in FIG. Figure 7 The cooling coefficient of the semiconductor cooling sheet 4 according to the embodiment of the present invention varies with temperature and current. The refrigeration coefficient is calculated as follows: Wherein, P is the total power consumed by the semiconductor refrigeration plate 4 to be tested P = αI(T h 'T c )+I 2 R x , (7) It is obtained by multiplying formula (1) by the operating current I.

[0064] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solution of the present invention. Without limitation, although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for measuring characteristic parameters of a semiconductor refrigeration sheet, characterized in that: The method comprises the following steps: S1: Setting the working current, energizing the semiconductor refrigeration piece to be tested, and measuring the hot end temperature and the cold end temperature of the semiconductor refrigeration piece to be tested in a steady state; S2: Keeping the temperature of the hot end unchanged, heating the cold end of the semiconductor refrigeration piece to be tested by using a heater so that the temperature difference between the hot and cold ends is zero; The heater is adjusted to reduce the temperature of the cold end to a target temperature, and the heating power of the heater is measured accordingly; the target temperature includes a sequence of temperature values ​​which are less than the temperature of the hot end and greater than the temperature of the cold end; Cut off the power supply to the semiconductor refrigeration piece to be tested, so that the temperature of the cold end rises to the target temperature, and correspondingly measures the electromotive force between the cold end and the hot end; S3: Calculate the Seebeck coefficient and resistance value of the semiconductor refrigeration piece to be tested; S4: Calculate the thermal conductivity of the semiconductor cooling plate to be tested according to a first formula, wherein the first formula is specifically: Wherein, K is the thermal conductivity, α is the Seebeck coefficient, I is the working current, T c is a temperature value of the target temperature, T h is the hot end temperature, R x is the resistance value, and P is the heating power.

2. The method for measuring characteristic parameters of a semiconductor refrigeration sheet according to claim 1, characterized in that: The step of calculating the Seebeck coefficient of the semiconductor refrigeration piece to be tested includes calculating the Seebeck coefficient according to a second formula, wherein the second formula is specifically: α=U / (T h ′T c ), Wherein, U is the electromotive force.

3. The method for measuring characteristic parameters of a semiconductor refrigeration sheet according to claim 2, characterized in that: The step of calculating the resistance value of the semiconductor refrigeration plate to be tested includes calculating the resistance value according to a third formula, and the third formula is specifically: Among them, R x is the resistance value.

4. The method for measuring characteristic parameters of a semiconductor refrigeration sheet according to claim 1, characterized in that: In step S2, the step of maintaining the hot end temperature constant includes dissipating heat from the hot end of the semiconductor refrigeration plate to be tested based on the heat sink so that the hot end temperature is constantly equal to the ambient temperature.

5. The method for measuring characteristic parameters of a semiconductor refrigeration sheet according to claim 1, characterized in that: In step S2, the step of heating the cold end of the semiconductor refrigeration chip to be tested based on the heater includes placing the heating surface of the heater in close contact with the cold end of the semiconductor refrigeration chip to be tested, and heating the heating surface through a thin film heating resistor.

6. The method for measuring characteristic parameters of a semiconductor refrigeration sheet according to claim 1, characterized in that: The method further includes setting different working currents and repeating steps S1-S4 to obtain the thermal conductivity coefficient of the semiconductor refrigeration plate to be tested under different working currents.

7. The method for measuring characteristic parameters of a semiconductor refrigeration sheet according to claim 1, characterized in that: The method for calculating the resistance value includes a double-arm bridge method.

8. The method for measuring characteristic parameters of a semiconductor refrigeration sheet according to claim 1, characterized in that: The step S3 also includes calculating the Peltier coefficient and the refrigeration efficiency.

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