US20150059358A1

US20150059358A1 - Controlling method for thermoelectric cooling device and heat-dissipating module employing same

Info

Publication number: US20150059358A1
Application number: US14/149,440
Authority: US
Inventors: Meng-Sheng CHANG
Original assignee: Delta Electronics Inc
Current assignee: Delta Electronics Inc
Priority date: 2013-09-04
Filing date: 2014-01-07
Publication date: 2015-03-05
Also published as: TWI534405B; TW201510464A

Abstract

A controlling method for a thermoelectric cooling device is provided. The thermoelectric cooling device has a cold side and a hot side. After the thermoelectric cooling device is enabled, a temperature of the cold side and an ambient temperature around the thermoelectric cooling device are acquired. By judging whether the ambient temperature is higher than or equal to a preset reference temperature, an initial value of a duty cycle corresponding to an electric energy to be received by the thermoelectric cooling device is set. Then, a judging step is performed to judge whether the temperature of the cold side is higher than or equal to the ambient temperature. If the judging condition is satisfied, the duty cycle is increased by a specified percentage. If the judging condition is not satisfied and the duty cycle is higher than 0%, the duty cycle is decreased by the specified percentage.

Description

FIELD OF THE INVENTION

The present invention relates to a controlling method, and more particularly to a controlling method for a thermoelectric cooling device and a heat-dissipating module employing the same.

BACKGROUND OF THE INVENTION

Recently, with increasing development of industrial technologies and science, a variety of electronic devices are gradually improved, so that the functions and the processing speeds of these electronic devices are enhanced. Consequently, the electronic components within these electronic devices must have high power or high integration level. During operation of the electronic devices, the electronic components may generate energy in the form of heat. If no proper heat-dissipating mechanism is provided to transfer enough heat to the ambient air, the elevated operating temperature may result in damage of the electronic components or breakdown of the whole electronic device. For maintaining normal operations of the electronic device and extending the use life of the electronic device, it is important to dissipate the heat from the electronic device.
Generally, the heat-dissipating mechanism for removing heat from the optical components or electronic components of a high power electronic device (e.g. a projector or a personal computer) includes a heatsink with a plurality of heat pipes or a liquid cooling mechanism. However, the applications of the heatsink and the liquid cooling mechanism are restricted. As known, the heat of the components that generate high power and withstand low temperature can't be effectively removed by the heatsink or the liquid cooling mechanism. For increasing heat-dissipating efficiency and reliability, a thermoelectric cooling device is gradually used.
The thermoelectric cooling device is substantially a PN semiconductor device. When a current passes through the thermoelectric cooling device, two sides of the thermoelectric cooling device become a cold side and a hot side, respectively. Due to a temperature difference between the cold side and hot side, the temperature of the cold side is very low. The cold side of the thermoelectric cooling device is in contact with the component to be cooled. The hot side of the thermoelectric cooling device is hotter than the cold side. However, the use of the thermoelectric cooling device still has some drawbacks. For example, if the temperature of the cold side of the thermoelectric cooling device is lower than the ambient temperature, the thermoelectric cooling device and the inner component of the electronic device may result in dew or even generate moisture vapor. Under this circumstance, the reliability and the use life of the electronic device are reduced.
Therefore, there is a need of providing a controlling method for a thermoelectric cooling device and a heat-dissipating module using the thermoelectric cooling device in order to eliminate the above drawbacks.

SUMMARY OF THE INVENTION

The present invention provides a controlling method for a thermoelectric cooling device and a heat-dissipating module using the thermoelectric cooling device. By judging the relationship between the temperature of the cold side of the thermoelectric cooling device and the ambient temperature, the duty cycle corresponding to the electric energy to be received by the thermoelectric cooling device is selectively increased or decreased. In case that the temperature of the cold side of the thermoelectric cooling device is higher than or equal to the ambient temperature, the chilling efficiency of the cold side of the thermoelectric cooling device is enhanced by increasing the duty cycle. In case that the temperature of the cold side of the thermoelectric cooling device is lower than the ambient temperature, the duty cycle is decreased, so that the possibility of resulting in dew and generating moisture vapor is minimized. When the heat-dissipating module of the present invention is used to remove heat from electronic components of an electronic device, the influence of the moisture vapor on the electronic components are largely reduced. Consequently, the reliability and the use life of the electronic device are enhanced.
In accordance with an aspect of the present invention, there is provided a controlling method for a thermoelectric cooling device. The thermoelectric cooling device has a cold side and a hot side. In a step (a), the thermoelectric cooling device is enabled, and a temperature of the cold side and an ambient temperature around the thermoelectric cooling device are acquired. Then, a step (b) is performed to judge whether the ambient temperature is higher than or equal to a preset reference temperature. In a step (c), an initial value of a duty cycle corresponding to an electric energy to be received by the thermoelectric cooling device is set according to a judging result of the step (b). Then, a step (d) is performed to judge whether the temperature of the cold side is higher than or equal to the ambient temperature. In a step (e), if the judging condition of the step (d) is satisfied, the duty cycle is increased by a specified percentage, and the step (d) is repeatedly performed. In a step (f), if the judging condition of the step (d) is not satisfied, the duty cycle is decreased by the specified percentage and the step (d) is repeatedly performed by judging whether the duty cycle is higher than 0%.
In accordance with another aspect of the present invention, there is provided a heat-dissipating module. The heat-dissipating module comprises a thermoelectric cooling device, a power supply circuit, a first temperature sensor, a second temperature sensor, and a controller. The thermoelectric cooling device has a cold side and a hot side. The power supply circuit is electrically connected with the thermoelectric cooling device and operated at a duty cycle for providing electric energy to the thermoelectric cooling device and driving the thermoelectric cooling device. The first temperature sensor is disposed adjacent to the cold side of the thermoelectric cooling device for detecting the temperature of the cold side. The second temperature sensor is used for detecting the ambient temperature around the thermoelectric cooling device. The controller is electrically connected with the first temperature sensor, the second temperature sensor and the power supply circuit, judges whether the temperature of the cold side of the thermoelectric cooling device is higher than or equal to the ambient temperature according to a detecting result of the first temperature sensor and the second temperature sensor, and adjusts the duty cycle of the power supply circuit according to a judging result for adjusting the electric energy provided by the power supply circuit correspondingly.
The above contents of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic circuit block diagram illustrating the architecture of a heat-dissipating module according to an embodiment of the present invention;

FIG. 2 is a schematic view illustrates some components of the heat-dissipating module according to the embodiment of the present invention;

FIG. 3 is a flowchart illustrating a method for controlling a thermoelectric cooling device according to an embodiment of the present invention; and

FIG. 4 is a flowchart illustrating a method for controlling a thermoelectric cooling device according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only. It is not intended to be exhaustive or to be limited to the precise form disclosed.
FIG. 1 is a schematic circuit block diagram illustrating the architecture of a heat-dissipating module according to an embodiment of the present invention. As shown in FIG. 1, the heat-dissipating module 1 comprises a first temperature sensor 10, a second temperature sensor 11, a power supply circuit 12, a controller 13, and a thermoelectric cooling device 14. The power supply circuit 12 is electrically connected with the thermoelectric cooling device 14. Moreover, the power supply circuit 12 is operated at a specified duty cycle in order to provide electric energy to the thermoelectric cooling device 14 and drive the thermoelectric cooling device 14. The thermoelectric cooling device 14 is a PN semiconductor device with a cold side 140 and a hot side 141 (see FIG. 2). The cold side 140 and the hot side 141 are located at two opposite sides of the thermoelectric cooling device 14. After the thermoelectric cooling device 14 is enabled by receiving the electric energy from the power supply circuit 12, the cold side 140 of the thermoelectric cooling device 14 generates a chilling effect. Meanwhile, the hot side 141 is relatively hotter than the cold side 140. The first temperature sensor 10 is used for detecting the temperature of the cold side 140 of the thermoelectric cooling device 14. The second temperature sensor 11 is used for detecting an ambient temperature around the thermoelectric cooling device 14, i.e. the ambient temperature around the heat-dissipating module 1.
The controller 13 is electrically connected with the first temperature sensor 10, the second temperature sensor 11 and the power supply circuit 12. According to the detecting results of the first temperature sensor 10 and the second temperature sensor 11, the controller 13 judges whether the temperature of the cold side 140 of the thermoelectric cooling device 14 is higher than or equal to the ambient temperature. According to the judging result, a duty cycle of the power supply circuit 12 is adjusted by the controller 13. After the duty cycle of the power supply circuit 12 is adjusted, the electric energy provided by the power supply circuit 12 is correspondingly adjusted.
FIG. 2 is a schematic view illustrates some components of the heat-dissipating module according to the embodiment of the present invention. As shown in FIGS. 1 and 2, the cold side 140 of the thermoelectric cooling device 14 is located near an electronic component 9. After the thermoelectric cooling device 14 is enabled, the cold side 140 of the thermoelectric cooling device 14 can cool the electronic component 9. In addition, the first temperature sensor 10 is disposed adjacent to the cold side 140 of the thermoelectric cooling device 14. Of course, the first temperature sensor 10 may be in direct contact with the cold side 140 of the thermoelectric cooling device 14 in order to measure the temperature of the cold side 140 more accurately.
Optionally, the heat-dissipating module 1 further comprises a plurality of fins 15. As shown in FIG. 2, the fins 15 are disposed on the hot side 141 of the thermoelectric cooling device 14 for transferring the heat of the hot side 141 through thermal conduction. Optionally, the heat-dissipating module 1 further comprises a third temperature sensor 16. The third temperature sensor 16 is located near or disposed on the hot side 141 of the thermoelectric cooling device 14. Moreover, the third temperature sensor 16 is electrically connected with the controller 13. The temperature sensor 16 is used for detecting the temperature of the hot side 141 of the thermoelectric cooling device 14. In case that the temperature of the hot side 141 of the thermoelectric cooling device 14 exceeds a protective temperature, the controller 13 may control the power supply circuit 12 to stop providing electric energy to the thermoelectric cooling device 14. Consequently, the heat-dissipating module 1 can be protected. The protective temperature may be previously determined according to the practical requirements. For example, the maximum withstandable temperature may be set as the protective temperature.
Hereinafter, a method for controlling the thermoelectric cooling device 14 by the controller 13 will be illustrated with reference to FIGS. 1, 2 and 3. FIG. 3 is a flowchart illustrating a method for controlling a thermoelectric cooling device according to an embodiment of the present invention. Firstly, in the step S1, the heat-dissipating module 1 is enabled (i.e. the thermoelectric cooling device 14 is enabled). Then, in the step S2, the temperature of the cold side 140 of the thermoelectric cooling device 14 and the ambient temperature around the thermoelectric cooling device 14 are acquired. The temperature of the cold side 140 of the thermoelectric cooling device 14 is detected by the first temperature sensor 10. The ambient temperature around the thermoelectric cooling device 14 is detected by the second temperature sensor 11. Then, in the step S3, the controller 13 judges whether the ambient temperature is higher than or equal to a preset reference temperature. For example, the preset reference temperature is 30° C., but is not limited thereto.
Then, in the step S4, an initial value of a duty cycle of the power supply circuit 12 corresponding to the electric energy to be received by the thermoelectric cooling device 14 is set according to the judging result of the step S3. The step S4 comprises two sub-steps S40 and S41. In particular, either the sub-step S40 or the sub-step S41 is performed according to the judging result of the step S3. If the ambient temperature is higher than or equal to the preset reference temperature (e.g. 30° C.), the initial value of the duty cycle of the power supply circuit 12 is set as 50% by the controller 13. That is, the sub-step S40 is performed. Under this circumstance, since the power supply circuit 12 can provide higher electric energy to the thermoelectric cooling device 14 at the initial stage, the cooling rate of the cold side 140 of the thermoelectric cooling device 14 is higher. Meanwhile, in response to the high ambient temperature, the heat of the electronic component 9 can be quickly removed at the higher cooling rate by the thermoelectric cooling device 14.
On the other hand, if the ambient temperature is lower than the preset reference temperature, the judging condition of the step S3 is not satisfied. Meanwhile, the initial value of the duty cycle of the power supply circuit 12 is set as 0% by the controller 13. That is, the sub-step S41 is performed. Under this circumstance, since the ambient temperature is low, the power supply circuit 12 needn't to provide high electric energy to the thermoelectric cooling device 14 immediately and the cooling rate of the cold side 140 of the thermoelectric cooling device 14 is lower at the initial stage. Therefore, the initial value of the duty cycle of the power supply circuit 12 is set as 0% by the controller 13.
After the step S4, the step S5 is performed. In the step S5, the controller 13 judges whether the temperature of the cold side 140 of the thermoelectric cooling device 14 is higher than or equal to the ambient temperature. If the judging condition of the step S5 is satisfied, the cold side 140 of the thermoelectric cooling device 14 will not result in dew. Consequently, the duty cycle of the power supply circuit 12 is continuously increased to increase the output electric energy of the power supply circuit 12. Under this circumstance, the step S6 is performed. In the step S6, the duty cycle of the power supply circuit 12 is increased by a specified percentage (e.g. 1%) by the controller 13. Meanwhile, the temperature of the cold side 140 is continuously decreased, and the chilling effect is enhanced. Consequently, the heat of the electronic component 9 can be quickly removed at the higher cooling rate by the thermoelectric cooling device 14.
On the other hand, if the judging condition of the step S5 is not satisfied, the cold side 140 of the thermoelectric cooling device 14 may result in dew and generate moisture vapor. For minimizing the possibility of resulting in dew and generating moisture vapor, the duty cycle of the power supply circuit 12 should be decreased. Then, the step S7 is performed to judge whether the duty cycle of the power supply circuit 12 is higher than 0%. If the judging condition of the step S7 is not satisfied (Namely, if the duty cycle of the power supply circuit 12 is equal to 0%), the step S5 is performed again. Whereas, if the judging condition of the step S7 is satisfied, the step S8 is performed. In the step S8, the duty cycle of the power supply circuit 12 is decreased by a specified percentage (e.g. 1%) by the controller 13. Since the duty cycle of the power supply circuit 12 is decreased, the output electric energy of the power supply circuit 12 is decreased. Under this circumstance, the temperature of the cold side 140 of the thermoelectric cooling device 14 is gradually increased, and the possibility of resulting in dew and generating moisture vapor is minimized.
FIG. 4 is a flowchart illustrating a method for controlling a thermoelectric cooling device according to another embodiment of the present invention. In this embodiment, the sub-step S40 of the step S4 of FIG. 3 is replaced by the sub-step S40′. In the step S40′, an initial value of a duty cycle of the power supply circuit 12 corresponding to the electric energy to be received by the thermoelectric cooling device 14 is set according to the judging result of the step S3 after a delaying time. Under this circumstance, the cooling rate of the cold side 140 of the thermoelectric cooling device 14 is gradually increased, and the heat of the electronic component 9 is gradually removed by the thermoelectric cooling device 14. Consequently, the possibility of resulting in dew and generating moisture vapor is minimized.
From the above descriptions, the present invention provides a controlling method for a thermoelectric cooling device and a heat-dissipating module using the thermoelectric cooling device. By judging the relationship between the temperature of the cold side of the thermoelectric cooling device and the ambient temperature, the duty cycle corresponding to the electric energy to be received by the thermoelectric cooling device is selectively increased or decreased. In case that the temperature of the cold side of the thermoelectric cooling device is higher than or equal to the ambient temperature, the chilling efficiency of the cold side of the thermoelectric cooling device is enhanced by increasing the duty cycle. In case that the temperature of the cold side of the thermoelectric cooling device is lower than the ambient temperature, the duty cycle is decreased, so that the possibility of resulting in dew and generating moisture vapor is minimized. When the heat-dissipating module of the present invention is used to remove heat from electronic components of an electronic device, the influence of the moisture vapor on the electronic components are largely reduced. Consequently, the reliability and the use life of the electronic device are enhanced.
While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.

Claims

What is claimed is:

1. A controlling method for a thermoelectric cooling device, the thermoelectric cooling device having a cold side and a hot side, the method comprising steps of:

(a) enabling the thermoelectric cooling device, and acquiring a temperature of the cold side and an ambient temperature around the thermoelectric cooling device;

(b) judging whether the ambient temperature is higher than or equal to a preset reference temperature;

(c) setting an initial value of a duty cycle corresponding to an electric energy to be received by the thermoelectric cooling device according to a judging result of the step (b);

(d) judging whether the temperature of the cold side is higher than or equal to the ambient temperature;

(e) if the judging condition of the step (d) is satisfied, increasing the duty cycle by a specified percentage, and repeatedly performing the step (d); and

(f) if the judging condition of the step (d) is not satisfied, decreasing the duty cycle by the specified percentage and repeatedly performing the step (d) by judging whether the duty cycle is higher than 0%.

2. The controlling method according to claim 1, wherein in the step (c), if the ambient temperature is higher than or equal to the preset reference temperature, the initial value of the duty cycle is set as 50%.

3. The controlling method according to claim 1, wherein in the step (c), if the ambient temperature is higher than or equal to the preset reference temperature, the initial value of the duty cycle is set as 50% after a delaying time.

4. The controlling method according to claim 1, wherein in the step (c), if the ambient temperature is lower than the preset reference temperature, the initial value of the duty cycle is set as 0%.

5. The controlling method according to claim 1, wherein in the step (b), the preset reference temperature is 30° C.

6. The controlling method according to claim 1, wherein in the step (f), if the duty cycle is higher than 0%, the duty cycle is decreased by the specified percentage, and the step (d) is repeatedly done.

7. The controlling method according to claim 1, wherein in the step (f), if the duty cycle is equal to 0%, the step (d) is repeatedly done.

8. A heat-dissipating module, comprising:

a thermoelectric cooling device having a cold side and a hot side;

a power supply circuit electrically connected with the thermoelectric cooling device and operated at a duty cycle for providing electric energy to the thermoelectric cooling device and driving the thermoelectric cooling device;

a first temperature sensor disposed adjacent to the cold side of the thermoelectric cooling device for detecting a temperature of the cold side;

a second temperature sensor for detecting an ambient temperature around the thermoelectric cooling device; and

a controller electrically connected with the first temperature sensor, the second temperature sensor and the power supply circuit, judging whether the temperature of the cold side of the thermoelectric cooling device is higher than or equal to the ambient temperature according to a detecting result of the first temperature sensor and the second temperature sensor, and adjusting the duty cycle of the power supply circuit according to a judging result for adjusting the electric energy provided by the power supply circuit correspondingly.

9. The heat-dissipating module according to claim 8, wherein the controller performs a controlling method comprising steps of:

(a) enabling the thermoelectric cooling device, and acquiring the temperature of the cold side and the ambient temperature around the thermoelectric cooling device;

(c) setting an initial value of the duty cycle corresponding to an electric energy to be received by the thermoelectric cooling device according to a judging result of the step (b);

10. The heat-dissipating module according to claim 8, wherein the first temperature sensor is in direct contact with the cold side of the thermoelectric cooling device.

11. The heat-dissipating module according to claim 8, further comprising a plurality of fins disposed on the hot side of the thermoelectric cooling device for transferring the heat of the hot side.

12. The heat-dissipating module according to claim 8, further comprising a third temperature sensor located near the hot side of the thermoelectric cooling device and electrically connected with the controller for detecting the temperature of the hot side, wherein when the temperature of the hot side of the thermoelectric cooling device exceeds a protective temperature, the controller controls the power supply circuit to stop providing electric energy to the thermoelectric cooling device.