JP5271119B2 - Heating element cooling device and heating element cooling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce an excessive cooling part of a heating element cooling device. <P>SOLUTION: The heating element cooling device includes a temperature detection means of detecting the temperature of a heating element, a differentiation means of differentiating the temperature detected by the temperature detection means with time, a difference means of obtaining the difference between the temperature detected by the temperature detection means and target temperature, a conversion means of nonlinearly converting the difference obtained by the difference means, a comparison means of outputting a signal for increasing cooling power, a signal for decreasing the cooling power, or a signal for maintaining the cooling power in accordance with the output of the differentiation means and the output of the conversion means, and a cooling means of cooling the heating element while adjusting the cooling power in accordance with the signal output from the comparison means. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a heating element cooling device and a heating element cooling method for cooling a heating element such as an electronic device.

  In recent years, the amount of heat generated by component elements has become a problem with the development of the semiconductor field.

  In addition, for the purpose of achieving multi-functionality and high output in systems such as computer equipment, the fact that such component elements, which are heating elements, are mounted at a high density has also spurred the problem of heat generation.

  Excessive heat becomes a problem for the stable operation of electronic devices, so an improved approach by cooling design is required.

  Currently, sufficient cooling characteristics cannot be obtained only by natural heat radiation of the element itself, so forced cooling with a fan or the like is an indispensable technology.

  Forced cooling with a fan or the like has the effect of reducing the heat dissipation resistance to the atmosphere and can improve the cooling characteristics.

  On the other hand, noise problems associated with fan operation have been pointed out in recent years.

  The cause of noise is very complicated due to complex factors such as wind noise, mechanical / vibration noise, and wind convection in the object to be cooled.

  In addition, it is difficult to perform a theoretical analysis that directly associates the fan speed with cooling performance and noise level. In designing, it is mainstream to optimize the fan speed by actual measurement of noise and component element temperature.

  Therefore, it is very troublesome to find the optimum fan control for noise and cooling, and the control program itself is very complicated.

  Thus, in recent years, a trade-off problem between cooling performance and noise has been pointed out, and a simple method for realizing fan control optimal for both characteristics is required.

Japanese Utility Model Publication No. 05-076093 JP 56-060041 A Japanese Patent Laid-Open No. 11-085323 JP-A-2005-347581

  In order to ensure the stable electrical characteristics and performance of the element from the conventional viewpoint, the first policy is to design the element temperature below a certain target temperature (element operating guarantee temperature). It was.

  However, in order to solve the trade-off problem between cooling and noise characteristics, it is necessary to actually measure and simulate each fan speed under each environmental condition to obtain a cooling performance exceeding the minimum required. It takes time and effort.

  Due to the difficulty of design and the complexity of control, unevenness in the cooling characteristics inevitably exists under specific conditions, and it has been difficult to obtain sufficient optimum conditions with the conventional design method.

  As an example, a problem example when a conventional cooling design is performed in a constant temperature environment is given.

  FIG. 1 shows the temperature characteristics of the heating element with respect to the electrical load in the case of forced cooling by a variable control fan referring to the element heat generation temperature and the electrical load and in the case of natural cooling (element heat dissipation characteristics).

  Basically, the cooling performance at the maximum load is emphasized with respect to the target temperature of the element. Therefore, when the load is low, the temperature margin tends to be large.

  An excessive temperature margin, such as the shaded area in FIG. 1, contributes to hindering the reduction of noise characteristics.

  Ideally, the noise is suppressed most when the minimum required cooling characteristics are maintained as shown in FIG.

  An object of the present invention is to provide a heating element cooling device and a heating element cooling method capable of reducing the excessive cooling portion that has remained due to the difficulty of conventional cooling design.

  According to the present invention, the temperature detection means for detecting the temperature of the heating element, the differentiation means for time differentiation of the temperature detected by the temperature detection means, and the difference between the temperature detected by the temperature detection means and the target temperature Difference means for obtaining, a conversion means for nonlinearly converting the difference obtained by the difference means, a signal for increasing the cooling power, a signal for reducing the cooling power, based on the output of the differentiation means and the output of the conversion means, or Comparing means for outputting a signal for maintaining the cooling power, and cooling means for cooling the heat generating element while adjusting the cooling power in accordance with the signal output from the comparing means. An apparatus is provided.

  According to the present invention, the temperature detection step for detecting the temperature of the heating element, the differentiation step for time differentiation of the temperature detected by the temperature detection step, the temperature detected by the temperature detection step, and the target temperature, A difference step for obtaining the difference, a conversion step for nonlinearly converting the difference obtained by the difference step, a signal for increasing the cooling power, and a weakening of the cooling power based on the output of the differentiation step and the output of the conversion step A comparison step for outputting a signal or a signal for maintaining the cooling power, and a cooling step for cooling the heating element while adjusting the cooling power in accordance with the signal output in the comparison step. A body cooling method is provided.

  According to the present invention, the excessive cooling portion can be reduced.

It is a graph of an electric load versus element temperature for explaining that an overcooling part occurs when a cooling method according to related art is applied. It is a graph of an electric load versus element temperature for explaining that an excessive cooling portion does not occur when the present invention is applied. It is a block diagram which shows the structure of the heat generating body cooling device by embodiment of this invention. It is a figure which shows the conversion characteristic of the conversion circuit shown in FIG. It is a figure which shows the input-output relationship of the comparison circuit shown in FIG. It is a block diagram which shows the structure of the heat generating body cooling device by other embodiment of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  In the embodiment of the present invention, in order to maintain the necessary minimum cooling performance in any temperature / load environment, noise is minimized by controlling the temperature of the element so as to be a constant element target temperature. Realize.

  In short, in the embodiment of the present invention, the target temperature of the element is set, and the minute time temperature change amount of the element is controlled so as to approximate the target temperature.

  For example, in the range where the element temperature is equal to or lower than the target temperature, the rotation speed of the fan is controlled so that the temperature change amount becomes positive according to the amount of difference between the element temperature and the target temperature. Decrease the fan speed until it approaches the target temperature.

  Conversely, in the range where the element temperature is equal to or higher than the target temperature, the fan speed is controlled so that the temperature change amount becomes negative, and the fan speed is increased until the element temperature approaches the target temperature.

  By repeating the above operation, the element temperature is controlled to be always constant at the target temperature.

  FIG. 3 shows a configuration of the present embodiment.

  Referring to FIG. 3, the present embodiment includes a heating element 101, a temperature detection unit 103, a differentiation circuit 105, a difference circuit 107, a conversion circuit 109, a comparison circuit 111, a fan 113, and a fan 113 drive circuit 115.

  The temperature detection unit 103 is a circuit that measures the element temperature T of the electronic device that is the object to be cooled (heating element) 101. The temperature detection unit 103 is in contact with the object to be cooled (heating element) 101 or near the object to be cooled (heating element) 101 (the temperature at that position is affected by the temperature of the object to be cooled (heating element) 101. A thermistor 103-1 disposed at a position) and a resistance element 103-3 connected in series thereto. A voltage is applied to the terminal opposite to the terminal connected to the resistance element 103-3 of the thermistor 103-1 by a power source or the like, and the terminal opposite to the terminal connected to the thermistor 103-1 of the resistance element 103-3 is installed. Is done. A voltage corresponding to the temperature of the cooled object (heating element) 101 is output from the connection point between the thermistor 103-1 and the resistance element 103-3.

  The differentiation circuit 105 is a circuit that measures a temperature change amount dT / dt of a detected minute temperature.

  In the difference circuit 107, a target temperature To is set in advance at the design stage. The difference circuit 107 is a circuit that measures a temperature difference Td (= To−T) between the target temperature To and the input element temperature T.

  The conversion circuit 109 sets a target change amount dTo / dt corresponding to the temperature difference Td input from the difference circuit 107 in the previous stage, and converts the actually input temperature difference Td into the target change amount dTo / dt. It is.

  The comparison circuit 111 is a circuit that compares the input temperature change amount dT / dt and the target change amount dTo / dt, and outputs comparison result information.

  The fan 113 blows air to the cooled object (heating element) 101.

  The drive circuit 115 is a circuit that drives the fan 113 while controlling the rotational speed of the fan 113 according to the information input from the comparison circuit 111 in the previous stage.

  First, the temperature detection unit 103 obtains a voltage representing the element temperature T by dividing the power supply voltage by the thermistor 103-1 and the resistance element 103-3.

  The voltage representing the element temperature T is transmitted to the differentiation circuit 105 and the difference circuit 107, respectively.

  The differentiation circuit 105 measures a temperature change amount dT / dt in a minute time of the input element temperature T. This value is input to the comparison circuit 111.

  At the same time, the difference circuit 107 measures the temperature difference Td.

  The target temperature To is a design value obtained by subtracting a temperature margin from the maximum allowable temperature of the cooled object (heating element) 101.

  The obtained temperature difference Td is input to the conversion circuit 109.

  The conversion circuit 109 sets a target change amount dTo / dt corresponding to the input temperature difference Td, and the conversion circuit 109 converts the temperature difference Td into the target change amount dTo / dt.

  FIG. 4 shows a principle diagram of the conversion circuit 109.

  As shown in the left of FIG. 4, the design is made so that the target change amount dTo / dt is a function f (Td) that is substantially proportional to the temperature difference Td.

  That is, the design is such that the target change amount dTo / dt increases as the temperature difference Td increases, and the target change amount dTo / dt also becomes zero when the temperature difference Td is zero.

  Even when the temperature difference Td becomes a negative value, the target change amount dTo / dt is designed to increase in the negative direction if the absolute value of the temperature difference Td increases.

  However, as the absolute value of the temperature difference Td increases, the absolute value of the target change amount dTo / dt increases non-linearly (almost exponentially).

  As a result, as shown in the right of FIG. 4, the absolute value of the target change amount dTo / dt increases as the actual element temperature T is farther from the target temperature To, and the target change amount is reduced when the actual element temperature T approaches the target temperature To. Can be small.

  The comparison circuit 111 compares the target change amount dTo / dt output from the conversion circuit 109 with the temperature change amount dT / dt output from the differentiation circuit 105, and transmits a signal of the comparison result to the drive circuit 115.

  FIG. 5 shows an operation principle diagram of the comparison circuit 111.

  As shown in the left of FIG. 5, when the measured temperature change amount dT / dt is less than the target change amount dTo / dt, the fan is decelerated (cooling power is weakened). On the other hand, when the actually measured temperature change amount dT / dt exceeds the target change amount dTo / dt, the fan is accelerated (increase the cooling power). Further, when the measured temperature change amount dT / dt is equal to the target change amount dTo / dt, the fan speed is maintained (cooling power is maintained).

  Further, when considering the case where the element temperature is equal to or higher than the target temperature and the following case, the control is as shown on the right in FIG.

  That is, when the temperature difference Td is zero or more, the following occurs. That is, when the actually measured temperature change amount dT / dt is less than the target change amount dTo / dt, the fan is decelerated (cooling power is weakened). On the other hand, when the actually measured temperature change amount dT / dt exceeds the target change amount dTo / dt, the fan is accelerated (increase the cooling power). Further, when the measured temperature change amount dT / dt is equal to the target change amount dTo / dt, the fan speed is maintained (cooling power is maintained).

  Further, when the temperature difference Td is less than zero, the following occurs. That is, when the actually measured temperature change amount dT / dt is less than the target change amount dTo / dt, the fan is accelerated (increases the cooling power). On the other hand, when the actually measured temperature change amount dT / dt exceeds the target change amount dTo / dt, the fan is decelerated (cooling power is weakened). Further, when the measured temperature change amount dT / dt is equal to the target change amount dTo / dt, the fan speed is maintained (cooling power is maintained).

  In the drive circuit 115, the rotational speed of the fan is changed (the cooling power is adjusted) according to the control signal of the comparison circuit 111 in the previous stage.

  By repeating such temperature feedback control, the temperature of the cooled object (heating element) 101 can be made as shown in FIG.

  FIG. 6 shows a case where a sampling circuit 121 is used instead of the differentiation circuit 105 as another embodiment of the present invention.

  The sampling circuit 121 samples a voltage representing the temperature T of the cooled object (heat generating element) 101 at a certain period of time, and the temperature change amount dT / from the difference between the voltage sampled one period before and the currently sampled voltage. dt is obtained and output.

  Further, the memory circuit 123 has a function of combining the difference circuit 107 and the conversion circuit 109, and a temperature change amount dTo / dt is set in the memory circuit 123 as a function of the input element temperature T. That is, for example, in the memory circuit 123, the element temperature T is set as an address, and the temperature change amount dTo / dt is set as data.

  The comparison circuit 111 and the drive circuit 115 in FIG. 6 are the same as the comparison circuit 111 and the drive circuit 115 in FIG. 3, respectively.

  By determining the minimum cooling characteristics necessary for the electronic device to function according to this embodiment, it is possible to suppress excessive cooling and reduce fan noise.

  This embodiment will eventually remove the temperature margin, but this can be solved by setting the target temperature in consideration of the margin for each specific purpose, avoiding trade-offs with electronic device quality and lifetime. I can do it.

  The present invention can be applied to all mechanisms that require forced cooling by a fan, including computer equipment and other electronic equipment.

  In addition, the present invention is a temperature feedback control in which the temperature of the object to be cooled (heating element) is kept constant at the maximum set temperature, and can be applied to all cooling mechanisms that keep the temperature of the object to be cooled constant. is there.

  Furthermore, the present invention can be used for cooling using a liquid in addition to cooling using a gas.

DESCRIPTION OF SYMBOLS 101 Heat generating body 103 Temperature detection part 105 Differentiation circuit 107 Difference circuit 109 Conversion circuit 111 Comparison circuit 113 Fan 115 Drive circuit 121 Sampling circuit 123 Memory circuit

Claims (14)

Temperature detecting means for detecting the temperature of the heating element;
Differentiating means for differentiating the temperature detected by the temperature detecting means with respect to time,
Difference means for obtaining a difference between the temperature detected by the temperature detection means and the target temperature;
Conversion means for nonlinearly converting the difference obtained by the difference means;
Based on the output of the differentiating means and the output of the converting means, a comparison means for outputting a signal for increasing the cooling power, a signal for reducing the cooling power, or a signal for maintaining the cooling power;
Cooling means for cooling the heating element while adjusting the cooling power according to a signal output from the comparison means;
A heating element cooling device comprising: The heating element cooling device according to claim 1,
The heating unit cooling device, wherein the conversion unit converts the absolute value of the difference obtained by the difference unit into a target temperature change amount that exponentially increases as the absolute value increases . In the heating element cooling device according to claim 1 or 2,
The comparison means includes
When the output of the differentiating means is smaller than the output of the converting means, a signal for weakening the cooling power is output,
When the output of the differentiating means is larger than the output of the converting means, a signal for increasing the cooling power is output,
A heating element cooling device that outputs a signal for maintaining cooling power when the output of the differentiating means is equal to the output of the converting means. In the heating element cooling device according to claim 1 or 2,
The comparison means includes
If the difference is greater than or equal to zero,
When the absolute value of the output of the differentiating means is smaller than the absolute value of the output of the converting means, a signal for weakening the cooling power is output,
When the absolute value of the output of the differentiating means is larger than the absolute value of the output of the converting means, a signal for increasing the cooling power is output,
When the absolute value of the output of the differentiating means is equal to the absolute value of the output of the converting means, a signal for maintaining cooling power is output,
If the difference is less than zero,
When the absolute value of the output of the differentiating means is smaller than the absolute value of the output of the converting means, a signal for increasing the cooling power is output,
When the absolute value of the output of the differentiating means is larger than the absolute value of the output of the converting means, a signal for weakening the cooling power is output,
When the absolute value of the output of the differentiating means is equal to the absolute value of the output of the converting means, a heating element cooling device is provided that outputs a signal for maintaining cooling power. In the heating element cooling device according to any one of claims 1 to 4,
A heating element cooling apparatus comprising sampling means for periodically sampling the temperature detected by the temperature detection means and outputting a difference between adjacent sampled signals instead of the differentiation means. In the heating element cooling device according to any one of claims 1 to 5,
A heating element cooling apparatus comprising a memory circuit that obtains the same output as the output of the conversion means based on the temperature detected by the temperature detection means instead of the difference means and the conversion means. The heating element cooling device according to any one of claims 1 to 6,
The cooling means is
A fan for blowing air to the heating element;
Drive means for driving the fan while adjusting the rotational speed of the fan;
A heating element cooling device comprising: A temperature detection step for detecting the temperature of the heating element;
A differentiation step for time differentiation of the temperature detected by the temperature detection step;
A difference step for obtaining a difference between the temperature detected by the temperature detection step and the target temperature;
A conversion step for nonlinearly converting the difference obtained by the difference step;
Based on the output of the differentiation step and the output of the conversion step, a comparison step for outputting a signal for increasing the cooling power, a signal for reducing the cooling power, or a signal for maintaining the cooling power;
A cooling step of cooling the heating element while adjusting a cooling power according to a signal output in the comparison step;
A heating element cooling method comprising: In the heating element cooling method according to claim 8,
In the conversion step, the absolute value of the difference obtained in the difference step is converted into a target temperature change amount that exponentially increases as the absolute value increases .
In the heating element cooling method according to claim 8 or 9,
In the comparison step,
When the output in the differentiation step is smaller than the output in the conversion step, a signal for weakening the cooling power is output,
When the output in the differentiation step is larger than the output in the conversion step, a signal for increasing the cooling power is output,
A heating element cooling method characterized by outputting a signal for maintaining cooling power when the output in the differentiation step is equal to the output in the conversion step. In the heating element cooling method according to claim 8 or 9,
In the comparison step,
If the difference is greater than or equal to zero,
When the absolute value of the output in the differentiation step is smaller than the absolute value of the output in the conversion step, a signal for weakening the cooling power is output,
When the absolute value of the output in the differentiation step is larger than the absolute value of the output in the conversion step, a signal for increasing the cooling power is output,
When the absolute value of the output in the differentiation step is equal to the absolute value of the output in the conversion step, a signal for maintaining the cooling power is output,
If the difference is less than zero,
When the absolute value of the output in the differentiation step is smaller than the absolute value of the output in the conversion step, a signal for increasing the cooling power is output,
When the absolute value of the output in the differentiation step is larger than the absolute value of the output in the conversion step, a signal for weakening the cooling power is output,
A heating element cooling method characterized by outputting a signal for maintaining cooling power when the absolute value of the output in the differentiation step is equal to the absolute value of the output in the conversion step. The heating element cooling method according to any one of claims 8 to 11,
A heating element cooling method comprising a sampling step of periodically sampling the temperature detected by the temperature detection step and outputting a difference between adjacent sampled signals instead of the differentiation step. The heating element cooling method according to any one of claims 8 to 12,
Instead of the difference step and the conversion step, a heating element cooling method comprising a step of obtaining, by a memory circuit, the same output as the output of the conversion step based on the temperature detected by the temperature detection step . The heating element cooling method according to any one of claims 8 to 13,
The heating element cooling method, wherein the cooling step includes a driving step of driving the fan while adjusting a rotation speed of the fan that blows air to the heating element.

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