TW201421234A - Method and device for controlling fan speed - Google Patents

Abstract

A method and a device for controlling fan speed are provided. The device outputs a fan-speed controlling signal according to temperature of a target device, so as to control fan speed of at least one fan according to the fan-speed controlling signal. The method includes the following steps. First, an actual power of the target device is detected. Then, the fan-speed controlling signal is adjusted according to the actual power of the target device, wherein the actual power of the target device is negative correlation with the fan-speed controlling signal.

Description

Fan speed control method and device

The present invention relates to a fan control technique, and more particularly to a fan speed control method and apparatus that can adjust a fan speed control signal according to actual power of a target device.

At present, computer devices are generally equipped with heat sinks (such as heat sinks, fans, etc.), and among these heat sinks, fans are one of the indispensable parts. Because the fan can effectively exclude the heat source generated by the internal components and/or the device of the computer device from being outside the casing of the computer device, the various components and/or devices in the computer device can operate normally. In view of the commonly used proportional-integral-differential (PID) speed-controlled fan, it can generate Pulse Width Modulation (PWM) signals or pulse width modulation values according to changes in temperature. The pulse width modulation signal or pulse width modulation value is used to control and adjust the fan speed. For example, when the pulse width modulation value is increased, the fan speed is increased accordingly. When the pulse width modulation value decreases, the fan speed decreases accordingly.

In the normal PID speed control fan operation mode, when the temperature of a certain part or device in the computer device is low, the computer device usually lowers the pulse width modulation value corresponding to the part or device to reduce Fan speed and noise generated by fan operation, and saves power required for fan operation. However, for parts or devices with more severe temperature changes, the above operational mechanism is not appropriate. For example, suppose the central processor in the computer device When the central processing unit (CPU) lowers the temperature due to the lowering of its load (loading), the computer device will correspondingly reduce the pulse width modulation value to reduce the fan speed by the pulse width modulation value. However, it is assumed that the CPU will suddenly increase its temperature due to sudden load increase. At this time, the conventional PID control mechanism may not be able to increase the fan speed to an appropriate speed in real time, and it cannot be effective for the CPU. The ground dissipates heat, which in turn causes damage to the machine or device.

In order to avoid the above problems, for a part or device with a relatively high temperature change in a computer system, the corresponding pulse width modulation value is generally increased, or the fan is directly turned up in a normal state. However, this practice also causes unnecessary power consumption and noise of fan operation.

Therefore, how to balance the temperature of the components in the computer device and the power consumption of the fan operation is one of the important issues that the research and development personnel in the field are exerting.

In view of this, the present invention provides a fan speed control method and apparatus, which can effectively reduce the risk of damage caused by a large increase in the temperature of the target device.

The invention provides a fan speed control method, which is suitable for a fan speed control device, wherein a fan speed control device outputs a fan speed control signal according to a temperature of a target device to control a rotation speed of at least one fan according to a fan speed control signal, the fan speed The control method includes the following steps. Detect the actual power of the target device. The fan speed control signal is adjusted according to the actual power of the target device, wherein the actual power of the target device is negatively correlated with the fan speed control signal.

In an embodiment of the invention, the step of adjusting the fan speed control signal according to the actual power of the target device comprises the following steps. A temperature control parameter is generated based on the actual power of the target device. Adjust the fan speed control signal according to the temperature control parameters.

In an embodiment of the invention, the actual power of the target device is positively correlated with the temperature control parameter, and the temperature control parameter is negatively correlated with the fan speed control signal.

In an embodiment of the invention, the step of generating a temperature control parameter based on the actual power of the target device comprises the following steps. Temperature control parameters are generated based on the maximum power and actual power of the target device.

In an embodiment of the invention, the step of generating a temperature control parameter based on the maximum power and the actual power of the target device includes the following steps. The temperature control parameter is generated according to the equation, wherein the equation is PTC=PTCmax-Kc×(Pmax/P), wherein PTC is the temperature control parameter, PTCmax is the preset maximum value of the temperature control parameter, Kc is the adjustment coefficient, and Pmax is the target device. Maximum power, and P is the actual power of the target device.

The invention further provides a fan speed control device, which is adapted to output a fan speed control signal according to an actual temperature of the target device, to control the rotation speed of the at least one fan according to the fan speed control signal, wherein the fan speed control device comprises a detection module and Control module. Detection module for detecting target loading The actual power placed. The control module is coupled to the detection module for adjusting the fan speed control signal according to the actual power of the target device, wherein the actual power of the target device is negatively correlated with the fan speed control signal.

In an embodiment of the invention, the control module generates a temperature control parameter according to the actual power of the target device, and adjusts the fan speed control signal according to the temperature control parameter.

In an embodiment of the invention, the actual power of the target device is positively correlated with the temperature control parameter, and the temperature control parameter is negatively correlated with the fan speed control signal.

In an embodiment of the invention, the control module generates a temperature control parameter according to the maximum power and actual power of the target device.

In an embodiment of the invention, the control module generates a temperature control parameter according to an equation, and the equation is PTC=PTCmax-Kc×(Pmax/P), wherein the PTC is a temperature control parameter, and the PTCmax is a temperature control parameter preset. The maximum value, Kc is the adjustment factor, Pmax is the maximum power of the target device, and P is the actual power of the target device.

Based on the above, the fan speed control method and apparatus of the present invention can detect the actual power of the target device and adaptively adjust the fan speed control signal with the actual power of the target device. Thereby, when the actual power of the target device is small, the present invention can adaptively increase the fan speed control signal to prepare for heat dissipation of the target device which may be greatly increased at any time. When the actual power of the target device is large, the present invention adaptively lowers the fan speed control signal. Thereby, after the temperature of the target device is stabilized, The invention can adjust the fan speed to reduce the excess system energy consumption caused by maintaining excessive fan speed.

The above described features and advantages of the present invention will be more apparent from the following description.

In general, the Proportional-Integral-Differential (PID) speed control fan is mainly composed of a PID controller and a fan. The PID controller can output a fan speed control signal according to the temperature sensed by the temperature sensor, and the fan can adjust the fan speed according to the fan speed control signal output by the PID controller. The fan speed control signal is, for example, in the form of a Pulse Width Modulation (PWM) signal or a pulse width modulation value. In detail, the PID controller is mainly composed of a proportional controller, an integral controller, and a differential controller, and the proportional controller, the integral controller, and the differential controller can be used. The respective output results are combined into an output signal of the PID controller (hereinafter collectively referred to as a pulse width modulation signal PWM) to control the rotation speed of the fan by the pulse width modulation signal PWM.

Under the Continuous Time System, the proportional-integral-derivative controller can generate PWM(t) at time t by the following equation:

In equation (1-1), Kp, Ki, and Kd are scale factor, integral coefficient, and differential coefficient, respectively, and can be fine-tuned separately for each value in the equation (1-1). Further, e(t) is a temperature error value obtained by subtracting a preset value from the sensed temperature at time t. It is worth mentioning that, in the case of a general PID controller, the above preset value is usually a fixed value (for example, -10), and it cannot be adaptively adjusted.

On the other hand, under the Discrete Time System, Equation (1-1) can be converted as follows:

Among them, the coefficients Kp, Ki, and Kd have been described in the equation (1-1), and therefore will not be described herein. And corresponding to e(t) in equation (1-1), e(k) in equation (1-2) is used to represent the temperature error obtained by subtracting the kth sensing temperature from the preset value. value.

Next, substituting k-1 for k into equation (1-2) yields the following equation:

Then, in order to obtain the PWM change between PWM(k) and PWM(k-1), subtract equation (1-2) from equation (1-3) to obtain the following equation: △ PWM = PWM ( k )- PWM ( k -1)= Kp ×[ e ( k )- e ( k -1)]+ Ki × e ( k )+ Kd ×[ e ( k )-2 e ( k -1)+ e ( k -2)] (1-4)

In equation (1-4), since e(k) represents a temperature error value obtained by subtracting the kth sensing temperature by a preset value, e(k) can be T(k)-SP, e(k-1) is substituted into equation (1-4) with T(k-1)-SP and e(k-2) with T(k-2)-SP, and the following equation can be obtained: △ PWM = PWM ( k )- PWM ( k -1)= Kp ×[ T ( k )- T ( k -1)]+ Ki ×[ T ( k )- SP ]+ Kd ×[ T ( k )-2 e ( k -1)+ T ( k -2)] (1-5)

Where T(k) represents the kth sensing temperature and SP represents a fixed preset value (eg, -10). As can be seen from equation (1-5), when the SP value is set larger, the amount of change in ΔPWM is smaller. When the SP value is set smaller, the amount of change of ΔPWM is larger. That is to say, the set value of the SP value is inversely proportional to the amount of change of the ΔPWM. Assuming that the central processing unit (CPU) in the computer device lowers the temperature due to the temporary load reduction, the computer device correspondingly reduces the pulse width modulation value by lowering the pulse. Wide adjustments reduce fan speed. However, when the temperature of the CPU is suddenly increased due to sudden load increase, if the fan speed is not increased to the proper speed, the CPU will not be effectively dissipated and the system will easily become The machine or device is damaged.

According to equation (1-5), in order to quickly increase the PWM output of the PID controller when the fan speed needs to be increased, the PWM value is generally improved by lowering the SP value in equation (1-5). The amount of change. Or, also The problem of not being able to dissipate heat instantaneously can be avoided by increasing the basic speed of the fan. However, these methods require continuous improvement of the fan speed, resulting in an increase in energy consumption.

Therefore, the present invention provides a fan speed control method that can detect the actual power of the target device and adaptively adjust the fan speed control signal with the actual power of the target device. For example, when the actual power of the target device is small (for example, when the load of the central processing unit is low), the fan speed control signal is adaptively adjusted to prepare for heat dissipation of the target device which may be greatly increased at any time. When the actual power of the target device is large (for example, when the load of the central processing unit is high), the fan speed control signal is adaptively lowered. Thereby, when the power of the target device suddenly increases sharply, the present invention can quickly raise the fan speed control signal to the appropriate size based on the increased fan speed control signal to increase the fan speed to dissipate heat to the target device. In addition, after the temperature of the target device is stabilized, the present invention can adjust the fan speed to reduce excess system energy consumption caused by maintaining excessive fan speed.

1 is a functional block diagram of a fan speed control device according to an embodiment of the invention. Referring to FIG. 1 , in the embodiment, the fan speed control device 10 , the target device 11 , and the fan 12 can be disposed in various electronic devices, such as a notebook computer and a tablet PC. A fan can be installed in various types such as a desktop computer, an industrial computer, or a server host to serve as an electronic device for heat dissipation. The target device 11 can be a component or device in various electronic devices, such as a central processing unit, a power supply, a display card, a network card, and the like. The present invention is not limited in terms of a chip, an interface card, and various parts or devices that are ubiquitous in various computer devices. Further, the fan 12 may be various fan devices that can adjust the fan speed according to a fan speed control signal (for example, PWM), and the present invention does not limit the number of the target device 11 and the fan 12.

Specifically, in essence, the fan rotational speed control device 10 can output the fan rotational speed control signal PWM according to the temperature of the target device 11 to control the rotational speed of the fan 12 according to the fan rotational speed control signal PWM. Generally, when the temperature of the target device 11 rises, the fan rotational speed control device 10 correspondingly increases the value of the fan rotational speed control signal PWM (hereinafter collectively referred to as PWM) to control the fan to increase the rotational speed by a higher PWM. When the temperature of the target device 11 drops, the fan speed control device 10 correspondingly lowers the PWM to control the fan to reduce the rotational speed by a lower PWM. Regarding the above, the detailed description may refer to the foregoing description and the conventional PID control technology, and details are not described herein again.

It is worth mentioning that the fan speed control device 10 includes a detection module 101 and a control module 102, and the detection module 101 is coupled to the control module 102. In this embodiment, the detection module 101 can be a hardware-implemented power detection device, and the control module 102 can be a micro-controller, an embedded controller, or a central processing unit. A central processing unit (CPU) or the like, but the embodiments of the present invention are not limited to the above. Alternatively, the detection module 101 and the control module 102 may also be a hard disk or a memory stored in the electronic device 10. The body program or software module in the middle can be loaded into the processor of the fan speed control device 10 to perform the above functions.

FIG. 2 is a schematic flow chart of a method for controlling a fan speed according to an embodiment of the invention. The fan speed control device 10 and the fan speed control method according to the embodiment of the present invention will be described in detail below with reference to FIG. Referring to FIG. 1 and FIG. 2 simultaneously, in step S202, the detection module 101 detects the actual power of the target device 11 and transmits the detected actual power of the target device 11 to the control module 102. Next, in step S204, the control module 102 adjusts the fan speed control signal PWM according to the actual power of the target device 11. In particular, in the present embodiment, the actual power of the target device 12 and the fan rotational speed control signal PWM are presented as a negative correlation or inverse ratio. In other words, when the actual power of the target device 11 is increased, the control module 102 corresponds to the actual power boosted by the target device 11, and reduces the fan speed control output by the fan speed control device 10 corresponding to the temperature of the target device 11. Signal PWM. In addition, when the actual power of the target device 11 decreases, the control module 102 adjusts the actual power of the target device 11 to reduce the fan speed control signal PWM output by the fan speed control device 10 corresponding to the temperature of the target device 11. .

Specifically, in this embodiment, the control module 102 can generate the temperature control parameter PTC according to the actual power of the target device 11, and adjust the fan speed control signal PWM according to the temperature control parameter PTC. The substantial function of the temperature control parameter PTC mentioned in this embodiment is similar to the SP in equation (1-5), and can be used to determine the temperature error in the PID controller. Difference. However, the difference is that the temperature control parameter PTC mentioned in the embodiment is substantially adaptively generated according to the actual power of the target device 11, which is not a fixed value.

In more detail, in order to improve the computational accuracy, the control module 102 can also generate the temperature control parameter PTC according to the maximum power and actual power of the target device 11. For example, the control module 102 can generate a temperature control parameter PTC according to the following equation: PTC=PTCmax-Kc×(Pmax/P) (2-1)

Wherein, PTCmax is the preset maximum value of the temperature control parameter to avoid the generated temperature control parameter PTC exceeding the preset maximum value of the temperature control parameter. Kc is an adjustment coefficient, where Kc can be any value of zero or greater than zero. For example, when Kc is zero, the PTC is equal to PTCmax. When Kc gradually increases from zero, the PTC will correspondingly become larger. Pmax is the maximum power of the target device 11, and P is the actual power of the target device 11.

It can be known from equation (2-1) that the actual power of the target device 11 exhibits a positive correlation with the temperature control parameter PTC, while the temperature control parameter PTC and the fan rotational speed control signal PWM exhibit a negative correlation. In other words, when the actual power of the target device 11 decreases, the control module 102 lowers the temperature control parameter PTC corresponding to the reduced actual power of the target device 11, and by lowering the temperature control parameter PTC. The fan speed control device 10 is turned on to output the fan speed control signal PWM corresponding to the temperature of the target device 11. Thereby, for the target device 11 which may increase the temperature significantly at any time, it will help to reduce the time required to raise the fan speed control signal PWM. On the other hand, when the target device 11 When the actual power is increased, the control module 102 adjusts the temperature control parameter PTC corresponding to the actual power of the target device 11, and lowers the fan speed control device 10 by adjusting the temperature control parameter PTC. The fan speed control signal PWM outputted by the temperature of the target device 11. Thereby, after the temperature of the target device 11 is stabilized (for example, the temperature of the target device 11 does not exceed the temperature that would cause the device to be damaged), by lowering the fan speed, the fan speed can be effectively reduced due to the excessively high fan speed. The excess system consumes energy.

It is worth mentioning that although Equation (2-1) is an implementable embodiment proposed in an embodiment of the present invention, it is not intended to limit the present invention. That is to say, the parameters in the equation (2-1) can be substantially increased or decreased or adjusted according to the design or practical requirements, and the invention is not limited thereto. In other words, the spirit of the present invention is to adjust the fan speed control signal PWM according to the actual power of the target device 11. Therefore, any method that can adjust the fan speed control signal PWM according to the actual power of the target device 11 is substantially in accordance with the present invention. One of the embodiments.

FIG. 3 is a schematic diagram of actual measurement results according to an embodiment of the invention. Referring to FIG. 3, a curve 301 is a graph showing a relationship between a fan speed control signal and a time corresponding to a target device (for example, the target device 11) in the embodiment, wherein the reference value of the fan speed control signal is the left vertical axis of FIG. And it is represented by PWM. The curve 302 is a graph of temperature versus time of the target device (for example, the target device 11) in the embodiment, wherein the temperature sensing value of the target device (for example, the target device 11) refers to the right vertical axis of FIG. 3, Is based on the sensing parameters in the PID control technology Show. Curve 303 is a graph showing the relationship between the fan speed control signal of the target device and time in an experiment conducted by a conventional PID control technique. Curve 304 is a graph showing the relationship between temperature and time of the target device in an experiment conducted by a conventional PID control technique. In addition, the time unit of the horizontal axis of FIG. 3 is in units of seconds.

Looking at the curve 301 and the curve 303, before 641 seconds, since the actual power of the target device (for example, the target device 11) is small, the PWM corresponding to the curve 301 (about 50) corresponds to the PWM corresponding to the curve 303 (about 25). high. In addition, since the PWM corresponding to the curve 301 is higher than the PWM corresponding to the curve 303, the fan rotation speed corresponding to the curve 301 is also higher than the fan rotation speed corresponding to the curve 303, so the temperature of the target device (for example, the target device 11) corresponding to the curve 302. It is also lower than the temperature corresponding to the curve 302.

Then, at about 641 seconds, since the load of the target device (for example, the target device 11) is greatly increased, the curve 301 and the curve 303 start to rise sharply. As seen by the curve 301 and the curve 303, after 641 seconds, the PWM (about 50) when the curve 301 starts to rise is higher than the PWM (about 25) when the curve 303 starts to rise, so the PWM corresponding to the curve 301 rises to the appropriate The time required for the PWM is shorter than the time required for the PWM corresponding to the curve 303 to rise to the appropriate PWM, and the target device (for example, the target device 11) can be dissipated relatively quickly. More clearly, when the temperature of the target device (for example, the target device 11) suddenly rises sharply, for the conventional PID control technology, the amount of PWM to be boosted is ΔPWM1, which is obviously more than the present invention. The amount of PWM required to be boosted (ie, ΔPWM2).

In addition, as seen by the curve 302 and the curve 304, before 641 seconds, since the temperature corresponding to the curve 302 is lower than the temperature corresponding to the curve 304, the fan is boosted according to the boosted PWM to target the device (for example, the target device). 11) After the heat is dissipated, the temperature drop rate corresponding to the curve 302 is also faster than the temperature drop rate corresponding to the curve 304. In addition, around 641 seconds, the temperature parameter corresponding to the highest point of the curve 302 (about -4) is higher than the temperature parameter corresponding to the highest point of the curve 302 (about -6), indicating that the present invention can effectively change the temperature. A more severe target device (eg, target device 11) dissipates heat.

Then, after the temperature of the target device (for example, the target device 11) is stabilized, as seen by the curve 301 and the curve 303, since the target device (for example, the target device 11) is maintained in a state of high load and high power, the curve 301 is caused. The corresponding PWM is lower than the PWM corresponding to the curve 303, so that the fan speed corresponding to the curve 301 is also lower than the fan speed corresponding to the curve 303, indicating that the present invention can effectively reduce the fan speed after the temperature of the target device is stabilized, and effectively Save energy. In particular, looking at the curve 302, after the temperature of the target device (for example, the target device 11) is stabilized, the temperature corresponding to the curve 302 is always maintained within an appropriate range, indicating that although the present invention causes the rotational speed of the fan to decrease, However, it is still effective to avoid damage caused by excessive temperature of the target device.

Further, assuming that the curve 301 is generated by the embodiment of the equation (2-1), corresponding to the adjustment coefficient Kc in the equation (2-1), when the adjustment coefficient Kc is increased, the curve 305 can be correspondingly generated. The characteristic of the curve 305 is similar to the curve 301, and will not be described again here.

In summary, the fan speed control method and apparatus according to the embodiment of the present invention can detect the actual power of the target device and adaptively adjust the fan speed control signal with the actual power of the target device. For example, embodiments of the present invention may generate temperature control parameters based on actual power of the target device and adjust fan speed control signals based on the temperature control parameters. When the actual power of the target device is small, the present invention can adaptively increase the fan speed control signal to prepare for heat dissipation of the target device which may be greatly increased at any time. In addition, the present invention adaptively lowers the fan speed control signal when the actual power of the target device is large. Thereby, the present invention can also adaptively reduce the fan speed after the temperature of the target device is stabilized, so as to reduce the excess system energy consumption caused by maintaining the excessive fan speed.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

10‧‧‧Fan speed control device

11‧‧‧ Target device

12‧‧‧Fan

101‧‧‧Detection module

102‧‧‧Control Module

301~305‧‧‧ Curve

S202, S204‧‧‧ steps of the fan speed control method according to an embodiment of the present invention

1 is a functional block diagram of a fan speed control device according to an embodiment of the invention.

FIG. 2 is a schematic flow chart of a method for controlling a fan speed according to an embodiment of the invention.

FIG. 3 is a schematic diagram of actual measurement results according to an embodiment of the invention.

S202, S204‧‧‧fan speed control method steps

Claims (10)

A fan speed control method is applicable to a fan speed control device, and the fan speed control device outputs a fan speed control signal according to a temperature of a target device to control the rotation speed of the at least one fan according to the fan speed control signal, the fan The speed control method includes: detecting an actual power of the target device; and adjusting the fan speed control signal according to the actual power of the target device, wherein the actual power of the target device is negatively correlated with the fan speed control signal. The fan speed control method according to claim 1, wherein the step of adjusting the fan speed control signal according to the actual power of the target device comprises: generating a temperature control parameter according to the actual power of the target device; and according to the temperature The control parameter adjusts the fan speed control signal. The fan speed control method according to claim 2, wherein the actual power of the target device is positively correlated with the temperature control parameter, and the temperature control parameter is negatively correlated with the fan speed control signal. The fan speed control method according to claim 2, wherein the step of generating the temperature control parameter according to the actual power of the target device comprises: generating the temperature control parameter according to the maximum power of the target device and the actual power. The fan speed control method according to claim 4, wherein the step of generating the temperature control parameter according to the maximum power of the target device and the actual power comprises: generating the temperature control parameter according to a program, wherein the equation is: PTC=PTCmax-Kc×(Pmax/P), where PTC is the temperature control parameter, PTCmax is a preset maximum value of the temperature control parameter, Kc is an adjustment coefficient, Pmax is the maximum power of the target device, and P The actual power of the target device. A fan speed control device is configured to output a fan speed control signal according to an actual temperature of a target device to control the rotation speed of the at least one fan according to the fan speed control signal, wherein the fan speed control device comprises: a detection module For detecting the actual power of the target device, and a control module coupled to the detection module for adjusting the fan speed control signal according to the actual power of the target device, wherein the actual power of the target device is The fan speed control signal exhibits a negative correlation. The fan speed control device according to claim 6, wherein the control module generates a temperature control parameter according to the actual power of the target device, and adjusts the fan speed control signal according to the temperature control parameter. The fan speed control device according to claim 7, wherein the actual power of the target device and the temperature control parameter are positive Correlation, and the temperature control parameter is negatively correlated with the fan speed control signal. The fan speed control device of claim 7, wherein the control module generates the temperature control parameter according to the maximum power of the target device and the actual power. The fan speed control device according to claim 9, wherein the control module generates the temperature control parameter according to a program, and the equation is: PTC=PTCmax-Kc×(Pmax/P), wherein the PTC is the The temperature control parameter, PTCmax is a preset maximum value of the temperature control parameter, Kc is an adjustment coefficient, Pmax is the maximum power of the target device, and P is the actual power of the target device.