JP2000112574A - Cooling fan control method - Google Patents

Abstract

(57) [Summary] [Problem] When low-speed rotation can be dealt with, operation is performed at low-speed rotation as much as possible, suppressing an increase in power consumption, reducing noise, and reducing the frequency of frequency switching near a specified temperature. To provide a cooling fan control system with reduced noise caused by noise. SOLUTION: In addition to controlling the cooling fan to operate at a low speed when the ambient temperature falls below a specified temperature a, the cooling fan is operated at a low speed only when all the cooling fans are operating normally, When a part of the cooling fan fails or when the ambient temperature exceeds the specified temperature a, the rotation is switched to the normal rotation (A). Switching from the normal rotation to the low-speed rotation is performed by performing hysteresis control for switching to the low-speed rotation at a temperature c further reduced from the specified temperature a to a certain temperature (re), so that the rotation speed is switched around the specified temperature. , Excessive switching can be prevented, noise caused by a beat can be reduced, and the life can be prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling fan control method in an information processing apparatus and the like, and more particularly, to a first rotation mode having a first rotation speed and a second rotation mode having a lower rotation speed than the first rotation speed. The present invention relates to a cooling fan control method when a plurality of cooling fans having a second rotation mode having a speed are mounted in a redundant configuration.

[0002]

2. Description of the Related Art In general, an information processing apparatus includes a CPU unit comprising a board (CPU board) on which an LSI chip such as a processor and a memory are mounted, a storage unit having a hard disk, and an input / output unit on which various IO boards are mounted. It is composed of a device section, a power supply section and the like. Each of these devices generates heat as they operate. On the other hand, the operating temperature ranges of these devices are determined in order to guarantee good operation. For this reason, a method of cooling by providing a cooling fan to keep the temperature in the apparatus below a specified temperature is generally used.

The amount of heat generated by an information processing apparatus greatly varies depending on the operating speed of a CPU and the mounting capacity of a memory or a hard disk. In general, when designing an information processing apparatus, a cooling design should be made in consideration of the maximum heat generation. It is usually done. Therefore, there is considerable room for cooling performance during normal operation. On the other hand, since cooling fans cause noise, recently, variable-speed cooling fans were used, and when the ambient temperature was low due to the installation environment of the information processing device, the noise level was reduced by rotating at low speed. There is something.

As a specific known example, Japanese Patent Application Laid-Open No. H09-25 / 09
Japanese Patent Application Laid-Open No. 0489/1994 “Cooling fan rotation speed control device” (hereinafter referred to as “known example 1”) and Japanese Patent Application Laid-Open No. 06-042494 “Variable rotation control cooling fan” (hereinafter referred to as known example 2). In the publicly known example 1, a plurality of temperature sensors are provided at a plurality of locations in the information processing device housing,
A control method of a cooling fan that controls the number of rotations of the cooling fan based on a temperature signal obtained from the temperature sensor is disclosed. Further, the known example 2 has a temperature sensor that senses the temperature inside the information processing apparatus housing and a memory that stores temperature data inside the housing obtained by the temperature sensor, and uses a stored change data of the temperature inside the housing. There is disclosed a cooling fan control method which controls the rotation speed of the cooling fan by an inference method based on fuzzy theory and realizes optimal temperature control and low noise.

[0005]

In each of the above-mentioned known examples 1 and 2, only the ambient temperature is detected, and when the cooling capacity is sufficient at a low speed, the rotation speed of the cooling fan is reduced. is there. On the other hand, since cooling fans are mechanical components, they are more susceptible to failures than semiconductors and other devices.As a countermeasure, there are devices that can make the number of cooling fans redundant and continue operating even if some of the cooling fans fail. In general it is becoming. In such an apparatus, when the rotation speed is controlled only by the ambient temperature as disclosed in the above-mentioned publication, the rotation speed switching temperature is set low in consideration of the occurrence of a failure at low speed rotation, or the rotation speed is controlled at low speed. It is necessary to further enhance the cooling capacity during rotation. That is, in the conventional device, by taking into account the failure of the cooling fan, in a normal state where the cooling fan is in a normal state, there is a waste that the temperature is switched to the normal rotation even though the temperature rise can sufficiently cope with the low speed rotation. There is a problem that noise increases as power consumption increases. Further, if the rotational speed is simply switched at a specified value of the ambient temperature, if the ambient temperature drifts around the specified value, the rotational speed is frequently switched, and as a result, there is a problem that noise accompanied by a beat is generated.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to operate at a low-speed rotation as much as possible in the case of a temperature rise that can be sufficiently handled by a low-speed rotation, thereby suppressing an increase in power consumption and reducing noise. An object of the present invention is to provide a cooling fan control method, and to provide a cooling fan control method capable of reducing the frequency of switching of the number of revolutions near a specified temperature to thereby reduce noise accompanying a beat.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a cooling fan having a second rotation speed (low-speed rotation) when the ambient temperature falls below a specified temperature. In addition to the control to operate in the first mode, the redundant configuration of the cooling fan is also taken into consideration, and the operation is performed at the second rotation speed (low-speed rotation) only when all the cooling fans are operating normally. Only when the cooling fan fails or when the ambient temperature exceeds the specified temperature.
The rotation speed of the cooling fan is controlled by the ambient temperature so as to switch to the rotation speed (normal rotation, normal rotation) while taking into account the redundant configuration of the cooling fan.
With this configuration, the above-described problem in the related art is solved. Further, according to the present invention, switching from the second rotation mode (low-speed rotation) to the first rotation mode (normal rotation) is performed when the temperature exceeds a specified temperature, and conversely, the first rotation mode (normal rotation) To the second rotation mode (low speed rotation)
A so-called hysteresis control is performed, which is performed at a temperature lower than a predetermined temperature to a predetermined temperature.
With this configuration, it is possible to prevent excessive switching near the specified temperature at which the rotation speed is switched.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing an information processing apparatus provided with a redundantly configured cooling fan according to the present invention. In the figure, reference numeral 1 denotes a cooling fan which has a function of controlling the number of rotations and can be used by switching between low-speed rotation and normal rotation (normal rotation) by a rotation control signal from the outside. The case where a table is provided is shown. The cooling fan 1 has a signal line for a cooling fan rotation signal and a signal line for a cooling fan rotation control signal (2
Signal line for the speed control signal).
The signal line for the rotation signal is a signal line for notifying the cooling fan rotation detection circuit 5 described later of the cooling fan rotation signal, and the signal line for the cooling fan rotation control signal is a signal line for the cooling fan rotation control circuit 6 described later. And a signal line for receiving a cooling fan rotation control signal (two-speed control signal) from the controller, and switches the cooling fan between low-speed rotation and normal rotation (normal rotation) according to the voltage level.

Reference numeral 2 denotes an information processing device forcibly cooled by the cooling fan 1, and reference numeral 3 denotes a cooled portion including a CPU board and the like. In order to cool the cooled part 3 of the information processing device 2, a design is made that two cooling fans can be used at normal rotation to secure the cooling capacity. The other one is mounted as a redundant cooling fan. During normal operation, all three units are operating, and even if a failure occurs in one of the three units (single failure), the remaining two units can continue to operate.
Reference numeral 4 denotes a hot-pluggable plug-in / removable relay connector. When a failure occurs in one of the cooling fans, the failed cooling fan can be replaced without stopping other cooling fans.

Reference numeral 5 denotes a cooling fan rotation detection circuit, and reference numeral 6 denotes a cooling fan rotation control circuit. The cooling fan rotation detection circuit 5 detects a rotation state of each cooling fan based on a cooling fan rotation signal received from each cooling fan 1 via a signal line for a rotation signal, and detects a rotation abnormality (failure). When it is detected that the cooling fan of the second fan has a rotation abnormality (failure), the cooling fan rotation control circuit 6 is notified as a cooling fan failure report.

Reference numeral 7 denotes a temperature sensor. Although only one temperature sensor 7 is shown in FIG. 1, the temperature sensor 7 may be arranged at a plurality of locations of the information processing device 2 as necessary. The temperature sensor 7 detects the ambient temperature of the information processing apparatus 2 and notifies the cooling fan rotation control circuit 6 of the detected temperature as an intake air temperature. The cooling fan rotation control circuit 6 determines whether or not the inlet temperature notified from the temperature sensor 7 exceeds the operating temperature range, that is, whether or not the temperature is abnormal.

When the cooling fan rotation control circuit 6 receives a notification of a cooling fan failure report from the cooling fan rotation detecting circuit 5, the cooling fan for switching normal cooling fans other than the failed cooling fan to normal rotation is used. A rotation control signal is transmitted, and the remaining normal cooling fans are switched to normal rotation to secure cooling capacity. Further, when it is determined that the temperature is abnormal based on the inlet air temperature from the temperature sensor 7, the cooling fan rotation control circuit 6 sends a cooling fan rotation control signal for switching to normal rotation to all the cooling fans, and the cooling capacity. To secure.

FIG. 2 is a diagram for explaining a cooling fan control system according to the present invention. FIG. 2A shows the relationship between the inlet air temperature and the cooling capacity of a redundant cooling fan according to the present invention. (B) shows the cooling fan control method based on the operating state of the cooling fan and the ambient temperature state at each temperature point, and the details of the failure report processing.

In FIG. 1A, the horizontal axis represents the inlet temperature (° C.), and the vertical axis represents the cooling capacity. The cooling capacity during low-speed rotation of all fans is also shown. Each of the temperature points a to g on the horizontal axis indicates a point at which the rotation mode of the cooling fan is switched and a failure report process is performed.

Hereinafter, a cooling fan control system according to the present invention will be described with reference to FIGS. 2 (a) and 2 (b). The temperature point a is a specified temperature that is the upper limit of the temperature at which all the cooling fans can rotate at a low speed, and is 3 in the information processing apparatus 2 of the present embodiment.
It is set at 7.5 ° C. Therefore, the information processing device 2
In the operating temperature range (10 to 35 ° C.), all the cooling fans can operate at a low speed.

When the cooling fan is operating normally and operating at a low speed, the inlet air temperature reaches a specified temperature, that is, a temperature point a (3).
(7.5 ° C), all the cooling fans are switched from the low-speed rotation to the normal rotation (b). Conversely, if the inlet air temperature drops below the temperature point d, a warning process indicating that the outside air is too low is performed. (Record / report only the failure) and continue operation (b).

If the temperature exceeds the temperature point f during normal operation of the cooling fan and normal rotation, a warning process (only recording / reporting of a fault) is performed and the operation is continued (c). Further, when the temperature exceeds the temperature point g, an alarm process (shutdown power OFF) is performed, and the process is stopped (d). Conversely, even when the intake air temperature drops below the temperature point a, the rotation is not immediately switched to the low-speed rotation, but when the temperature falls below the temperature point a to a temperature point c (for example, 32 ° C.) lower by a predetermined temperature. To switch to low speed rotation,
The so-called hysteresis control is performed (e). By performing the hysteresis control, it is possible to suppress the occurrence of excessive rotation switching of the cooling fan in the vicinity of the temperature point a, reduce the noise caused by the beat, and extend the life of the cooling fan.

At the time of a single failure, as described above, the remaining cooling fan rotates normally without any condition. If a failure occurs in this state, a warning process (only recording / reporting of the failure) is performed,
Continue operation (f). Warning processing when the intake air temperature rises and exceeds temperature point b (failure recording / reporting only)
And continue the operation (g). Further, when the inlet air temperature rises and exceeds the temperature point e, an alarm process (shutdown power OFF) is performed and the process is stopped (h). Conversely, if the inlet air temperature drops below the temperature point d, a warning process (only recording / reporting of a fault) indicating that the outside air is too low is performed, and the operation is continued (re).

When a plurality of failures occur, the remaining fan rotates normally without any condition. If a failure occurs in this state, an alarm process (shutdown power OFF) is performed and the process is stopped (nu).

As described above, in the present embodiment, in a device having a redundant configuration with respect to the cooling fan, when all the cooling fans are rotating normally, there is considerable spare capacity in the cooling capacity. When all the cooling fans are normal and the ambient temperature is equal to or lower than the specified temperature a), all the cooling fans can be operated at a low speed, and a device with low power consumption and low noise can be realized. In particular, regarding the noise, in the configuration of the present embodiment, if three cooling fans having a noise characteristic of 41 dB at the time of normal rotation and 34 dB at the time of low speed rotation are operated in parallel, the noise as the device is 45.8 dB at the time of normal rotation. On the other hand, during low-speed rotation, it is reduced to 38.8 dB, and considerable quietness is achieved.

In the present embodiment of FIG. 1, three cooling fans have been described as an example (one of which is a redundant cooling fan). However, FIG. 3 shows an example of a configuration having a plurality of redundant cooling fans. FIG.
In the configuration example, three cooling fans are mounted on the inlet side and the exhaust side, respectively, and a 4 + 2 redundant configuration example is shown. FIG.
In the case of, when up to two of the installed cooling fans have failed, that is, when the number of the cooling fans is less than or equal to the number of redundant fans, all the cooling fans except for the failed cooling fan are switched to the normal rotation. At the same time, a warning process such as a fault report and a fault logging is performed, so that the device can continue operating. If three or more cooling fans have failed, that is, if more than the number of redundant fans have failed, all the cooling fans except the failed fan are switched to normal rotation and an alarm is issued. The processing is performed, and the information processing apparatus is shut down (power OFF) to be in a stopped state.

In the above-described embodiment, the control is performed such that all the cooling fans except for the failed cooling fan are rotated at the normal speed. In consideration of the cooling capacity of the cooling fan, the arrangement of the cooling fan, and the like, only some of the cooling fans may be selectively rotated normally.

[0023]

According to the present invention, in an information processing apparatus having a cooling fan having a redundant configuration, when all the cooling fans including the redundant cooling fan operate normally and the ambient temperature is equal to or lower than a specified temperature, the cooling fan is provided. Can be operated at a low speed to operate in a low power consumption state with low noise. When one cooling fan fails (single failure) or when the ambient temperature exceeds a specified temperature, the rotation is switched to the normal rotation and the cooling capacity can be secured. Furthermore, by providing hysteresis for switching the rotation speed between the normal rotation and the low-speed rotation near the specified temperature, it is possible to reduce noise accompanying a beat generated at the time of switching, and to prolong the life of the cooling fan. can do.

[Brief description of the drawings]

FIG. 1 is a diagram showing an information processing apparatus including a cooling fan having a redundant configuration according to the present invention.

FIG. 2 shows the relationship between the inlet air temperature and the cooling capacity of the redundantly configured cooling fan according to the present invention (a), and the method of controlling the cooling fan based on the ambient temperature state in the operating state of the cooling fan at each temperature point and the failure report processing. It is a figure which shows the content (b).

FIG. 3 is a diagram showing an information processing apparatus including a redundantly configured cooling fan according to the present invention, which is a configuration example having a plurality of redundant cooling fans.

[Explanation of symbols]

 1: cooling fan 2: information processing device 3: cooled section 4: relay connector 5: cooling fan rotation detection circuit 6: cooling fan rotation control circuit 7: temperature sensor

Claims (3)

[Claims] 1. A plurality of units having a redundant configuration having a first rotation mode each having a first rotation speed and a second rotation mode having a second rotation speed smaller than the first rotation speed. Cooling fans, fan abnormality detecting means for receiving a fan rotation signal from each cooling fan and detecting a failure of the cooling fan, and temperature detecting means for detecting an ambient temperature,
A cooling fan control having a cooling fan rotation control unit that receives a report of a cooling fan failure from the fan rotation abnormality detection unit and a report of a detected temperature from the temperature detection unit and sends a fan rotation control signal to the cooling fan. The cooling fan rotation control means, when there is no report of a cooling fan failure from the fan rotation abnormality detection means and the detected temperature received from the temperature detection means is a specified temperature or less, the cooling fan, A cooling fan control method for transmitting a fan rotation control signal for operating the cooling fan in a second rotation mode. 2. The cooling fan control method according to claim 1, wherein when a failure occurs in a part of the mounted cooling fans, if the number of failed failures is equal to or less than the number of redundant fans, the cooling fan excluding the failed cooling fan is provided. Switching the fan to the first rotation mode and performing fault reporting and fault logging to continue the operation of the apparatus. If the number of faults exceeds the redundant number, the cooling fans excluding the faulty cooling fan are replaced by the first. A cooling fan control method in an information processing device, wherein the cooling mode is switched to a rotation mode and the information processing device is stopped. 3. The cooling fan control method according to claim 1, wherein the cooling fan rotation control means is configured to output a cooling fan failure report from the fan rotation abnormality detection means.
When a detected temperature exceeding the specified temperature is received from the temperature detecting means during operation in the second rotation mode, a fan rotation control signal for operating the cooling fan in the first rotation mode is sent to continue the operation of the device. A fan rotation control signal for causing the cooling fan to operate in the second rotation mode when receiving a detected temperature lower than the predetermined temperature by a predetermined value or more from the temperature detection means during operation in the first rotation mode. The cooling fan control system characterized in that the cooling fan is sent.