| System and method for control of fan rotational speed -> Monitor Keywords |
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System and method for control of fan rotational speedRelated Patent Categories: Pumps, Condition Responsive Control Of Pump Drive Motor, By Control Of Electric Or Magnetic Drive MotorSystem and method for control of fan rotational speed description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060228223, System and method for control of fan rotational speed. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0001] The present invention relates to systems and methods for control of fan rotational speed, and more particularly, to a system and method for control of fan rotational speed of a fan according to a predetermined temperature interval. BACKGROUND OF THE INVENTION [0002] Computers have become indispensable tools during work and everyday life, and technological advances have brought about increases in the operational speed of the central processing unit (CPU) which allow the execution of more and more processor-intensive programs. However, a huge amount of heat energy is generated when a CPU is operated at high speed, which, in turn, has a considerable effect on the system. Minor effects include temporary system hangs, and major effects include unrecoverable disk or processor damage to the system. Thus, research into system heat-radiating ability is receiving more and more attention. [0003] Cooling through the use of a fan is the most commonly used radiating method in the market. This kind of radiating device is constructed of a fan and a heat sink device equipped with fins. This device is broadly applied in computer systems and other electronic devices based on its advantages of simple structure, low cost, safety, reliability, technical maturity, and so on. In order to quickly radiate a large amount of heat energy generated by the system heat sources, the rotational speed of the system radiating fan has to be accelerated. However, additional noise is generated by higher rotational speeds. In addition, regularly rotating the fan at high speed reduces its lifespan. [0004] In order to solve the problem mentioned above, a fan rotational speed control technique has appeared in the market. A temperature sensing device is utilized, wherein, according to the changes of system temperature, the fan rotational speed will also be altered. In this technique, the fan is operated in at least a low-speed rotation mode and a high-speed rotation mode. FIG. 1 illustrates how the fan rotational speed is controlled based on a critical temperature value. As shown in the diagram, the temperature changing curve 10 illustrates an electronic device (e.g. computer main frame, laptop, etc) with an installed two-speed fan (in addition to off). The critical temperature value is denoted as Ct and shown by the dashed, horizontal line. System temperature varies above and below this critical temperature depending on system utilization and environmental factors. As illustrated by the fan rotational speed line 12 in the diagram, when the system temperature exceeds the critical temperature value, the fan rotational speed controller will adjust the fan rotational speed into the high-speed rotation mode. Conversely, when the temperature drops below the critical temperature value, the fan rotational speed controller will adjust the fan rotational speed into the low-speed rotation mode. However, the present fan rotational control speed technique is still lacking. In particular, when the system temperature oscillates around the critical temperature value, the fan rotational speed controller has to continually respond and adjust the fan rotational speed in order to meet the requirements. Such frequent changes of the fan rotational speed will result in a shorter fan life. [0005] In order to solve the deficiency mentioned above, an improvement scheme is proposed. As shown in FIG. 2, the amount of a predetermined insignificant temperature change .DELTA.t is deducted from the critical temperature value Ct to form a second critical temperature value Ct.sub.1. A critical temperature interval exists between the critical temperature value Ct and the critical temperature value Ct.sub.1, that is the critical temperature value Ct is the upper limit and the other critical temperature value Ct.sub.1 is the lower limit (the difference of Ct minus the insignificant temperature change .DELTA.t). When the system temperature exceeds the critical temperature value Ct, the fan rotational speed controller adjusts the fan into the high-speed rotation mode. When the temperature drops below the critical temperature value Ct minus the insignificant temperature change .DELTA.t to the critical temperature value Ct1, the fan rotational speed controller will adjust the fan into the low-speed rotation mode. Using this technique, the fan can be kept at a stable speed for a longer time. However, this method cannot fully solve the problem of frequent rotational speed changes caused by oscillating temperature. As shown in the diagram, when the system temperature change curve 20 oscillates around the critical temperature value Ct.sub.1, sudden abrupt changes of the fan rotational speed will still occur. A sudden abrupt rotational speed change 220 can occur as shown by the fan rotational speed change line 220 at the relative points, and the lifespan of the fan will be degraded. [0006] For this reason, a system and a method for control of fan rotational speed is needed to avoid the deficiency of the previously mentioned technique, thus making the change of the fan rotational speed less sensitive to temperature oscillations, and hence remarkably prolonging the life of the fan, as well as reducing system noise. SUMMARY OF THE INVENTION [0007] In order to solve the problems of the prior art, a primary objective of the present invention is to provide a system for control of fan rotational speed that avoids repetitive changes of the fan rotational speed in a short period of time due to system temperature oscillations. [0008] Another objective of the present invention is to provide a method for control of fan rotational speed that achieves the objectives of saving power and prolonging the life of the fan. [0009] In order to achieve the above objectives, the system for control of fan rotational speed is applied in the electronic device with a built-in fan for temperature adjusting purposes. The system includes at the very least: a temperature interval recording module for at least recording the relative first fan rotational speed when the temperature is at least higher than a temperature interval and the relative second fan rotational speed when the temperature is lower than the temperature interval; a rotational speed recording module for recording the fan rotational speed when the fan is operating; a temperature detecting module for detecting the temperature of an exothermic object being adjusted by the fan and for outputting temperature parameters; and a determining module for determining whether the temperature parameter outputted by the temperature detecting module belongs to the temperature interval recorded by the temperature interval recording module and sending control signals accordingly. For the determining module, if the temperature parameter belongs to the temperature interval, the system keeps the same rotational speed for the fan operation, and, if the temperature parameter does not belong to the temperature interval, then according to the temperature parameters of the temperature interval recording module, it determines whether the relative fan rotational speed is the same as the fan rotational speed recorded in the rotational speed recording module. If the fan rotational speeds are not the same, according to the temperature parameter of the temperature interval recording module, it determines whether the temperature parameter is lower than the temperature interval. If the temperature parameter is lower, it slows down the fan rotational speed and then updates the fan rotational speed recorded in the rotational speed recording module with the latest fan rotational speed. On the contrary, if the temperature parameter is higher, it operates the fan with the rotational speed recorded in the rotational speed recording module. In contrast, if the fan rotational speeds are the same, then, according to the temperature parameter of the temperature interval recording module, it determines whether the temperature parameter is higher than the temperature interval. If the temperature parameter is higher, it speeds up the fan rotational speed and then updates the fan rotational speed recorded in the rotational speed recording module with the latest fan rotational speed. On the contrary, if the temperature parameter is lower, it operates the fan with the rotational speed recorded in the rotational speed recording module. [0010] The method for control of fan rotational speed is applied in an electronic device with a built-in fan for temperature adjusting purposes. The method at the very least includes the following procedures: making the electronic device at least record the relative first fan rotational speed when the temperature is at least higher than a temperature interval and the relative second fan rotational speed when the temperature is lower than the temperature interval, and recording the fan rotational speed when the fan is operating; making the electronic device detect the temperature of an exothermic object being adjusted by the fan, and outputting the temperature parameters; and making the electronic device determine whether the output temperature parameter belongs to the temperature interval recorded by the temperature interval recording module. If the temperature parameter belongs to the temperature interval, the method keeps the same rotational speed for the fan operation. If the temperature parameter does not belong to the temperature interval, then, according to the temperature parameter, it determines whether the relative fan rotational speed is the same as the recorded fan rotational speed. If the fan rotational speeds are not the same, then, according to the temperature parameter, it determines whether the temperature parameter is lower than the temperature interval. If the temperature parameter is lower, it slows down the fan rotational speed and then updates the fan rotational speed recorded in the electronic device with the latest fan rotational speed. On the contrary, if the temperature parameter is higher, it operates the fan with the rotational speed recorded in the electronic device. In contrast, if the fan rotational speeds are the same, then, according to the temperature parameter, it determines whether the temperature parameter is higher than the temperature interval. If the temperature parameter is higher, it speeds up the fan rotational speed and then updates the fan rotational speed recorded in the electronic device with the latest fan rotational speed. On the contrary, if the temperature parameter is lower, it operates the fan with the rotational speed recorded in the electronic device. [0011] Compared with the commonly used fan rotational speed control technique, sudden abrupt changes of fan rotational speed caused by the temperature oscillation can be avoided, according to the preset temperature interval of the system and the method for control of fan rotational speed of the present invention, so as to avoid the deficiency of the prior art, smooth the fan operational rotational speed, prolong the life of the fan, and reduce system noise. BRIEF DESCRIPTION OF THE DRAWINGS [0012] A better understanding of the present invention can be obtained when the forgoing detailed description is considered in conjunction with the following drawings, in which: [0013] FIG. 1 (PRIOR ART) is a diagram showing the commonly used critical temperature method for control of fan rotational speed; [0014] FIG. 2 (PRIOR ART) is a diagram showing the commonly used critical temperature method after compensating for insignificant temperature changes in the control of fan rotational speed; [0015] FIG. 3 is a block diagram showing the basic configuration of the system for control of fan rotational speed according to the present invention; [0016] FIG. 4 is a flow chart showing the operational procedures which focuses on the low and high speed mode of fan rotational speed according to the method for control of fan rotational speed of the present invention; and [0017] FIG. 5 is a relevant diagram of the method for control of fan rotational speed of the present invention, showing how the fan rotational speed varies with the critical temperature value, when progress the rotational speed control to the fan body. DETAILED DESCRIPTION OF THE PREFFERED EMBODIMENTS [0018] FIG. 3 is a block diagram showing the basic configuration of the system for control of fan rotational speed according to the present invention. As shown in the diagram, the fan rotational speed control system 3 includes at very least: a temperature detecting module 30, a temperature interval recording module 31, a rotational speed recording module 32, and a determining module 33, wherein the system 3 is connected to a fan body 4. The fan rotational speed control system 3 is implemented in the electronic device which adjusts the system temperature through the use of the fan. In the example, the electronic device is a server computer, and the fan of the fan body 4 is controlled at a low and a high rotational speed. [0019] The temperature detecting module 30 is used to detect the temperature parameter of an exothermic object (e.g. a CPU, etc.) being adjusted by the fan. In the example, the temperature detecting model 30 can be temperature detector, which is used to detect the system temperature in real time when the server is operating and sends out the system temperature to the determining module 33. Continue reading about System and method for control of fan rotational speed... Full patent description for System and method for control of fan rotational speed Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this System and method for control of fan rotational speed patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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