JP3601404B2 - Peltier control device and Peltier element control method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a Peltier device control technique, and more particularly to a Peltier control device and a Peltier device control method for controlling a Peltier device that keeps a device temperature such as an infrared sensor sensitive to the temperature of the device itself at a predetermined temperature. .
[0002]
[Prior art]
Conventionally, in order to stabilize the temperature characteristics of the device itself, a method of using a Peltier element to keep the temperature constant with respect to the ambient temperature has been used, but in this case, the difference between the ambient temperature and the device set temperature is different. As the size increases, the power consumption increases.
[0003]
As a conventional technique for solving such a problem, for example, there is a technique disclosed in Japanese Patent Laid-Open No. 6-181529. FIG. 3 is a graph showing the relationship between the environmental temperature and the device set temperature in the conventional temperature control. That is, in the prior art described in Japanese Patent Application Laid-Open No. 6-181529, as shown in FIG. 3, the temperature of the device is changed according to the environmental temperature, and the environmental temperature is changed within the temperature range in which the device can be used. The power consumption is reduced by reducing the amount of change in device temperature with respect to.
[0004]
[Problems to be solved by the invention]
However, when temperature control is performed using the conventional technology, the sensitivity of an imaging device such as an infrared sensor is sensitive to the temperature of the device itself. However, there was a problem that it was not stable.
[0005]
In the control of the Peltier element in the conventional technology, the ambient temperature and the temperature on the device are measured, and the set temperature is controlled from the respective temperatures. In this case, depending on the set temperature, the power consumption to the Peltier element is reduced. May increase. In this way, when the power consumption increases, when the heat inflow to the Peltier element increases, this heat cannot be processed, and the temperature of the Peltier element cannot be controlled. In such a case, the Peltier device may be damaged.
[0006]
The present invention has been made in view of such a problem, and an object thereof is to stabilize the temperature of the device itself according to the environmental temperature, to reduce power consumption, and to reduce the power consumption of the Peltier device. In order to provide a Peltier control device and a Peltier device control method capable of avoiding breakage of a Peltier device due to thermal runaway by resetting the set temperature so as to reduce the current before a thermal runaway in which the temperature cannot be controlled. is there.
[0007]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION according to claim 1, together with constantly measuring the current flowing to the Peltier element, in the produced Peltier controller to arbitrarily control the setting temperature of the Peltier element based on the measured current, always The current is monitored to reset the set temperature so as to reduce the current before the thermal runaway in which the Peltier element becomes impossible to control the temperature, so that control is performed to avoid damage to the Peltier element due to the thermal runaway. The Peltier control device is characterized in that it is configured .
The gist of the invention according to claim 2 is that an imaging device, the Peltier device, a current measuring unit that measures a current of the Peltier device, and a temperature of the Peltier device calculated from measurement data of the current measuring unit. A temperature setting unit for resetting the temperature, a driving circuit unit for driving the Peltier element based on a setting signal from the temperature setting unit, and a temperature sensor on the imaging device. Item 1 is a Peltier control device.
According to a third aspect of the present invention, there is provided a Peltier control device configured to constantly measure a current flowing through a Peltier element and to arbitrarily control a set temperature of the Peltier element based on the measured current. The Peltier device has a π-type series circuit in which two types of semiconductors, an N-type semiconductor and a P-type semiconductor, are joined by a first metal electrode and a second metal electrode .
The gist of the invention described in claim 4 is that the Peltier element includes a π-type series circuit in which two types of semiconductors, an N-type semiconductor and a P-type semiconductor, are joined by a first metal electrode and a second metal electrode. The Peltier control device according to claim 1 or 2 , wherein
The gist of the invention described in claim 5 is that, when a direct current flows from the N-type semiconductor side to the π-type series circuit, the first upper part of the π-type series circuit is caused by a Peltier effect. Endothermic occurs at the metal electrodes of the π-type series circuit, and at the same time, heat radiation occurs at the two lower second metal electrodes of the π-type series circuit, and the heat is transferred from the upper part to the lower part to cool or cool the object to be temperature-controlled. The Peltier control device according to claim 3 or 4, wherein the Peltier control device is configured to perform control to maintain the Peltier element at a predetermined temperature by heating.
The gist of the invention according to claim 6 is that the current flowing through the Peltier element is measured by the current measuring unit, and the measurement data is sent to the temperature setting unit, and the temperature setting unit is configured to measure the current in the current measuring unit. Based on the measurement data, a control signal that becomes the set temperature of the Peltier element is recalculated and sent to the drive circuit unit, and the drive circuit unit receives the temperature information from the temperature sensor on the imaging device and the temperature setting unit. 6. The apparatus according to claim 2 , wherein a difference between the control signals is detected and the output voltage of the driving circuit unit is changed so that the difference is reduced. 7. Peltier control device.
The gist of the invention according to claim 7 is that, when the temperature setting unit determines that the environmental temperature has changed based on the data measured by the current measurement unit, the temperature set to the Peltier element is different from the temperature. When the current flowing through the Peltier element gradually increases to maintain the difference in the temperature information from the temperature sensor, it is determined that the environmental temperature has sufficiently changed, and the set temperature for the Peltier element is reset. The Peltier controller according to any one of claims 2 to 6, wherein the temperature control is performed in a stepwise manner.
Further, the gist of the invention according to claim 8, as well as constantly measuring the current flowing to the Peltier element, in Lupe Peltier element control method to arbitrarily control the set temperature of the Peltier element based on the measured current, always It is preferable to perform a control for monitoring a current and resetting a set temperature so as to reduce the current before the thermal runaway in which the Peltier element becomes uncontrollable to prevent the Peltier element from being damaged due to the thermal runaway. The present invention resides in a characteristic Peltier device control method .
The gist of the invention described in claim 9 is to stabilize the device characteristics by performing step-like control for keeping the device set temperature constant while the environmental temperature is within a predetermined range. that Sons the Peltier element control method according to claim 8,.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
(First Embodiment)
FIG. 1 is a functional block diagram for explaining a Peltier control device 30 according to the first embodiment of the present invention. In FIG. 1, 1 is an imaging device, 2 is a Peltier element, 3 is a current measuring unit, 4 is a temperature setting unit, 5 is a drive circuit unit, 6 is a temperature sensor, and 30 is a Peltier control device.
[0009]
The Peltier control device 30 of the present invention can be applied to a control technique of the Peltier element 2 for keeping a device temperature such as an infrared sensor sensitive to the temperature of the device itself at a predetermined temperature. FIG. 1 shows the configuration.
[0010]
Referring to FIG. 1, a Peltier control device 30 according to the present embodiment includes an imaging device 1, a Peltier device 2, a current measurement unit 3 that measures a current of the Peltier device 2, and a Peltier device 2 based on measurement data of the current measurement unit 3. A temperature setting section 4 for calculating and resetting the temperature, a driving circuit section 5 for driving the Peltier element 2 based on a setting signal from the temperature setting section 4, and a temperature sensor 6 on the imaging device 1 are provided.
[0011]
The Peltier controller 30 having such a configuration is characterized in that the current flowing through the Peltier element 2 is always measured, and the set temperature of the device can be arbitrarily controlled based on the current.
[0012]
Thereby, the temperature of the device itself can be stabilized according to the environmental temperature, and the power consumption can be reduced. In addition, since the current is constantly monitored, the set temperature is reset so as to reduce the current before the Peltier element 2 undergoes thermal runaway in which the temperature cannot be controlled, and the Peltier element 2 is damaged by the thermal runaway. Is achieved.
[0013]
FIG. 2 is a model diagram for explaining the Peltier effect in the Peltier control device 30 of FIG. In FIG. 2, reference numeral 7 denotes an N-type semiconductor, 8 denotes a P-type semiconductor, and 9 and 10 denote metal electrodes.
[0014]
The imaging device 1 is an infrared sensor or the like whose sensitivity is sensitive to the temperature of the device itself, and needs to be maintained at a predetermined temperature (room temperature is sufficient). The device for maintaining the temperature is the Peltier element 2, and as shown in FIG. 2, an N-type semiconductor 7, a P-type semiconductor 8, a metal electrode 9 (first metal electrode), and a metal electrode 10 (second metal electrode). Consists of
[0015]
Next, the principle of temperature control performed by the Peltier device 2 will be described with reference to FIG. A direct current is applied from the N-type semiconductor 7 side to a π-type series circuit in which two types of semiconductors, an N-type semiconductor 7 and a P-type semiconductor 8, are joined by metal electrodes 9 and 10 (first metal electrode and second metal electrode). When a current is applied, heat is absorbed by the upper metal electrode 9 (first metal electrode) of the π-type series circuit due to the Peltier effect, and at the same time, the lower two metal electrodes 10 (second metal electrode) of the π-type series circuit are heated. The heat is transferred from the upper part to the lower part because heat radiation occurs at the electrode). By utilizing this principle, the device to be temperature-controlled is cooled or heated to maintain the device at a predetermined temperature.
[0016]
Next, the operation of the Peltier control device 30 (Peltier element control method) will be described. FIG. 4 is a graph showing the relationship between the environmental temperature and the device set temperature in the temperature control of the Peltier control device 30 according to the first embodiment of the present invention. In the present embodiment, as shown in FIG. 4, while the ambient temperature is within a predetermined range, the stability of device characteristics is ensured by performing step-like control for keeping the device set temperature constant. Further, since the current flowing through the Peltier element 2 is directly measured and monitored to control the Peltier element 2, power consumption can be reduced and thermal runaway can be avoided.
[0017]
The operation of the Peltier control device 30 (Peltier element control method) will be described in more detail. The current flowing through the Peltier element 2 is measured by the current measuring unit 3. The measurement data is sent to the temperature setting unit 4. The current measurement unit 3 can be realized by using an IC (integrated circuit) for current detection, or by connecting resistors in series and measuring the voltage and calculating the voltage.
[0018]
The temperature setting unit 4 re-calculates a control signal for setting the temperature of the Peltier element 2 based on the data measured by the current measuring unit 3 and sends the control signal to the drive circuit unit 5. The drive circuit unit 5 of the Peltier element 2 detects a difference between temperature information (voltage value) from the temperature sensor 6 on the imaging device 1 and a control signal (voltage value) from the temperature setting unit 4 and detects the difference (voltage). The output voltage of the drive circuit unit 5 is changed so that the difference is reduced. Since the current flowing through the Peltier element 2 changes according to the change in the output voltage of the drive circuit unit 5, the temperature of the Peltier element 2 can be controlled.
[0019]
Next, a method of controlling the temperature set value set by the temperature setting unit 4 based on the data measured by the current measuring unit 3 will be described. First, when there is not much difference between the set temperature to the Peltier element 2 and the temperature information from the temperature sensor 6 within a predetermined environmental temperature range, the current flowing through the Peltier element 2 can be small, but when the environmental temperature changes. In order to maintain this difference, the current flowing through the Peltier element 2 gradually increases. Therefore, when the current increases to some extent, it can be determined that the environmental temperature has changed sufficiently, and the set temperature for the Peltier element 2 is changed.
[0020]
Specifically, the temperature setting unit 4 calculates the set temperature, and changes the control signal to be set to reset the temperature, thereby reducing the temperature difference again and reducing the current. By resetting the temperature when the current has increased to some extent, the temperature can be controlled stepwise, and the device temperature can be stabilized in accordance with the change in the environmental temperature.
[0021]
As described above, according to the first embodiment, the following effects can be obtained. First, the first effect is that by controlling the temperature setting of the Peltier element 2 in a stepwise manner with respect to the environmental temperature, it is possible to stabilize the performance change with respect to the temperature of the device itself.
[0022]
The second effect is that the current flowing through the Peltier element 2 is always measured, and the temperature of the imaging device 1 is set based on the measured current, so that the optimal Peltier current can be controlled and the power consumption can be reduced. That is, reduction can be achieved.
[0023]
The third effect is that since the current flowing through the Peltier element 2 is monitored, when the current becomes extremely large, the set temperature can be arbitrarily changed, so that thermal runaway or breakage of the Peltier element 2 can be prevented. What you can do.
[0024]
(Second embodiment)
Next, an embodiment of the drive circuit unit 5 and the current measuring method will be described. FIG. 5 is a circuit diagram for explaining a Peltier control device 30 according to the second embodiment of the present invention. In FIG. 5, reference numeral 12 denotes a resistance element (R1), 13 denotes a resistance element (R2), 14 denotes a resistance element (R3), 15 denotes a resistance element (R4), 16 denotes an NPN transistor (TR1), and 17 denotes a PNP transistor (TR2). ) And 18 are NPN transistors (TR3), 19 is a PNP transistor (TR4), 20 is a control unit, 30 is a Peltier controller, V1 and V2 are emitter potentials, and V1 'and V2' are base potentials.
[0025]
The drive circuit unit 5 of the present embodiment includes a control unit 20, a resistance element 12 (R1), a resistance element 13 (R2), a resistance element 14 (R3), a resistance element 15 (R4), an NPN transistor 16 (TR1), It includes an NPN transistor 18 (TR3), a PNP transistor 17 (TR2), and a PNP transistor 19 (TR4), and includes the Peltier element 2 and the current measuring unit 3 described above.
[0026]
The control unit 20 uses a PID (Proportional Integration and Differential) control theory based on the temperature information sent from the temperature sensor 6 and the control signal sent from the temperature setting unit 4 in FIG. Based on this, the base potential V1 'and the base potential V2' are controlled. The current flowing through the Peltier device 2 is determined by the potential difference between the emitter potential V1 and the emitter potential V2 determined from the base potential V1 ′ and the base potential V2 ′ and the characteristics of the Peltier device 2. For example, when the difference between the set temperature and the environmental temperature increases, the current increases due to the characteristics of the Peltier device 2.
[0027]
Now, when the voltage is applied by the control unit 20 in the direction of the dashed line indicated by (1), the NPN transistor 16 (TR1) and the PNP transistor 19 (TR4) are activated due to the relationship between the base and emitter voltages, and the PNP transistor is activated. Transistor 17 (TR2) and NPN transistor 18 (TR3) are cut off, and a voltage of emitter potential V1−emitter potential V2 (where emitter potential V1> emitter potential V2) is applied to both ends of Peltier element 2. . As a result, a current flows in the direction of the broken line shown in (1), and a current flowing through the Peltier element 2 flows through the resistance element 15 (R4).
[0028]
When a voltage is applied by the control unit 20 in the direction of the alternate long and short dash line shown by (2), the NPN transistor 16 (TR1) and the PNP transistor 19 (TR4) are cut off due to the relationship between the base and emitter voltages. , PNP transistor 17 (TR2) and NPN transistor 18 (TR3) are activated, and a voltage of emitter potential difference {V2-V1} (where emitter potential V1 <emitter potential V2) is applied to both ends of Peltier element 2. You. As a result, the current flows in the direction of the alternate long and short dash line shown by (2), and the current flowing through the Peltier element 2 flows through the resistance element 13 (R2).
[0029]
As described above, the heat absorbing surface and the heat radiating surface of the Peltier element 2 are reversed depending on the direction of the current indicated by the dashed line indicated by (1) or the direction indicated by the alternate long and short dash line indicated by (2). Both are possible.
[0030]
The current measurement unit 3 is a voltage measurement IC (integrated circuit) that measures the voltage across the resistance element 13 (R2) and the resistance element 15 (R4) through which the current flowing through the Peltier element 2 passes.
[0031]
The current flowing through the Peltier element 2 can be obtained from the voltage value measured by the current measuring unit 3 and the resistance value of the resistance element 13 (R2) or the resistance element 15 (R4) according to Ohm's law. Information to be used.
[0032]
It should be noted that the present invention is not limited to the above embodiments, and it is clear that each embodiment can be appropriately modified within the scope of the technical idea of the present invention. In addition, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiment, and can be set to numbers, positions, shapes, and the like suitable for carrying out the present invention. In each drawing, the same components are denoted by the same reference numerals.
[0033]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained. First, the first effect is that by controlling the temperature setting of the Peltier element in a stepwise manner with respect to the environmental temperature, it is possible to stabilize the performance change with respect to the temperature of the device itself.
[0034]
The second effect is that the current flowing through the Peltier element is always measured, and the temperature of the imaging device is set based on the measured current, so that the optimal Peltier current can be controlled and the power consumption can be reduced. That is what we can do.
[0035]
The third effect is that since the current flowing through the Peltier element is monitored, when the current becomes extremely large, the set temperature can be changed arbitrarily, so that thermal runaway and breakage of the Peltier element can be prevented. is there.
[Brief description of the drawings]
FIG. 1 is a functional block diagram for explaining a Peltier control device according to a first embodiment of the present invention.
FIG. 2 is a model diagram for explaining a Peltier effect in the Peltier control device of FIG. 1;
FIG. 3 is a graph showing a relationship between an environmental temperature and a device set temperature in conventional temperature control.
FIG. 4 is a graph showing a relationship between an environmental temperature and a device set temperature in the temperature control of the Peltier control device according to the first embodiment of the present invention.
FIG. 5 is a circuit diagram for explaining a Peltier control device according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Image pick-up device 2 ... Peltier element 3 ... Current measurement part 4 ... Temperature setting part 5 ... Drive circuit part 6 ... Temperature sensor 7 ... N-type semiconductor 8 ... P-type semiconductor 9, 10 ... Metal electrode 12 ... Resistance element (R1)
13 ... resistance element (R2)
14 Resistive element (R3)
15 Resistance element (R4)
16 ... NPN transistor (TR1)
17 ... PNP transistor (TR2)
18 ... NPN transistor (TR3)
19: PNP transistor (TR4)
Reference numeral 20: control unit 30: Peltier control device V1, V2: emitter potential V1 ', V2': base potential

Claims (9)

A Peltier control device configured to constantly measure the current flowing through the Peltier element and to arbitrarily control the set temperature of the Peltier element based on the measured current ,
The current is constantly monitored, and a control is performed so as to prevent the Peltier element from being damaged by thermal runaway by resetting the set temperature so as to reduce the current before the Peltier element becomes unable to control the temperature. A Peltier control device characterized by being configured as described above. An imaging device, the Peltier device, a current measurement unit that measures the current of the Peltier device, a temperature setting unit that calculates and resets the temperature of the Peltier device from measurement data of the current measurement unit, and the temperature setting. The Peltier control device according to claim 1, further comprising: a drive circuit unit that drives the Peltier element based on a setting signal from the unit; and a temperature sensor provided on the imaging device. A Peltier control device configured to constantly measure the current flowing through the Peltier element and to arbitrarily control the set temperature of the Peltier element based on the measured current,
The Peltier control device, wherein the Peltier device has a π-type series circuit in which two types of semiconductors, an N-type semiconductor and a P-type semiconductor, are joined by a first metal electrode and a second metal electrode. The Peltier device, according to claim 1 or 2, characterized in that it has an N-type semiconductor and the P-type semiconductor of the two semiconductor a first metal electrode and a second π-type serial circuit formed by bonding a metal electrode Peltier control device. When a DC current flows from the N-type semiconductor side to the π-type series circuit, heat is absorbed by the first metal electrode on the π-type series circuit due to the Peltier effect, and Heat is released from the two second metal electrodes at the lower part of the circuit, and the heat is transferred from the upper part to the lower part, so that the object to be temperature-controlled is cooled or heated to keep the Peltier element at a predetermined temperature. The Peltier control device according to claim 3 , wherein the Peltier control device is configured to perform the control. The current flowing through the Peltier device is measured by the current measuring unit, and the measured data is sent to the temperature setting unit, and the temperature setting unit becomes the set temperature of the Peltier device based on the data measured by the current measuring unit. The control signal is recalculated and sent to the drive circuit unit, and the drive circuit unit detects a difference between the temperature information from the temperature sensor on the imaging device and the control signal from the temperature setting unit and reduces the difference. The Peltier control device according to any one of claims 2 to 5, wherein an output voltage of the drive circuit unit is changed so as to perform the control. The temperature setting unit, when it is determined that the environmental temperature has changed based on the measurement data in the current measurement unit, in order to maintain the difference between the temperature set from the temperature sensor and the set temperature to the Peltier element When the current flowing through the Peltier element gradually increases, it is determined that the environmental temperature has sufficiently changed, and the temperature control is performed stepwise by resetting the set temperature to the Peltier element. The Peltier control device according to any one of claims 2 to 6. With constantly measuring the current flowing to the Peltier element, in Lupe Peltier element control method to arbitrarily control the set temperature of the Peltier element based on the measured current,
A method of constantly monitoring current and resetting the set temperature so as to reduce the current before the thermal runaway in which the Peltier element cannot control the temperature and performing control to avoid damage to the Peltier element due to thermal runaway. A Peltier device control method characterized by the above-mentioned. Stepwise control to keep the device set temperature constant while the environmental temperature is within the specified range 9. The Peltier device control method according to claim 8, wherein stability of device characteristics is secured.

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