[0043] In order to be able to understand the above objectives, features and advantages of the present invention more clearly, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the application and the features in the embodiments can be combined with each other if there is no conflict.
[0044] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described here. Therefore, the protection scope of the present invention is not limited to the specific details disclosed below. Limitations of the embodiment.
[0045] figure 2 It shows a schematic flow chart of a method for controlling the speed of a brushless DC fan according to an embodiment of the present invention.
[0046] Such as figure 2 As shown, a method for controlling the speed of a brushless DC fan according to an embodiment of the present invention includes: step 202, detecting the real-time speed of the brushless DC fan; step 204, comparing the real-time speed with the target speed, According to the comparison result, the real-time rotation speed is adjusted by adjusting the current duty ratio of the driving voltage of the brushless DC fan, so that the real-time rotation speed matches the target rotation speed.
[0047] According to the method for controlling the rotation speed of the brushless DC fan according to the embodiment of the present invention, the current duty ratio of the driving voltage of the fan is increased or decreased according to the comparison result of the real-time rotation speed of the brushless DC fan and the target rotation speed. The output voltage of the fan is precisely controlled to achieve precise control of the fan speed, so that the real-time speed of the fan and the target speed of the fan have little deviation or the real-time speed is equal to the target speed (that is, the real-time speed matches the target speed), and when the real-time speed matches the target speed When the rotation speed matches the target rotation speed, the noise of the refrigerator can be minimized.
[0048] According to an embodiment of the present invention, it further includes: setting a plurality of difference intervals for the difference between the real-time rotation speed and the target rotation speed, and setting different duty cycle adjustment amounts for the plurality of difference intervals, and The difference interval and the duty cycle adjustment amount are correspondingly stored.
[0049] According to the method for controlling the rotational speed of a brushless DC fan according to an embodiment of the present invention, by setting a plurality of difference intervals according to the difference between the real-time rotational speed and the target rotational speed, and setting a corresponding duty cycle adjustment amount for each difference interval, After calculating the difference between the real-time rotation speed and the target rotation speed, according to the difference interval where the difference is located, the corresponding duty cycle adjustment value is called to realize the precise adjustment of the current duty cycle of the fan. Of course, in order to further improve the control accuracy of the fan speed, each difference interval and the duty cycle adjustment amount corresponding to each difference interval can be further refined, so that each difference interval is very small, and each difference interval The corresponding duty cycle adjustments are very accurate.
[0050] According to an embodiment of the present invention, adjusting the duty cycle of the driving voltage of the brushless DC fan specifically includes: when the comparison result is that the real-time speed is greater than the target speed, according to the real-time speed and the In the difference interval in which the difference of the target speed is located, the duty cycle adjustment amount corresponding to the difference interval is called, and the current duty cycle of the driving voltage is reduced by the duty cycle adjustment amount; The comparison result is that when the real-time rotation speed is less than the target rotation speed, according to the difference interval where the difference between the real-time rotation speed and the target rotation speed is located, the duty cycle adjustment amount corresponding to the difference interval is called, and Increasing the current duty cycle of the driving voltage by the duty cycle adjustment amount.
[0051] According to the method for controlling the rotation speed of a brushless DC fan according to an embodiment of the present invention, when the real-time rotation speed is greater than the target rotation speed, it means that the real-time rotation speed is larger, and the output voltage of the fan is higher. , Can reduce the duty cycle of the driving voltage, thereby reducing the output voltage of the fan and the real-time speed of the fan, so that the real-time speed of the fan matches the target speed; similarly, when the real-time speed is less than the target speed, the real-time speed is smaller , The output voltage of the fan is low. By increasing the current duty cycle by the duty cycle adjustment amount, the duty cycle of the driving voltage can be increased, thereby increasing the output voltage of the fan and the real-time speed of the fan, making the real-time speed of the fan Match with the target speed, and once the real-time speed of the fan matches the target speed, the noise of the refrigerator is very low, so as to minimize the noise of the refrigerator.
[0052] According to an embodiment of the present invention, it further includes: determining whether the duration of the current duty cycle of the driving voltage is greater than or equal to a first preset time, and when the determination result is yes, starting to detect the brushless DC fan Real-time speed.
[0053] According to the method for controlling the rotation speed of the brushless DC fan according to the embodiment of the present invention, since the current duty cycle of the driving voltage is unstable and may fluctuate, when the real-time rotation speed of the fan starts to be detected, the current duty ratio of the driving voltage must be determined. Only when the air ratio is stable (that is, the duration of the current duty cycle is greater than or equal to the first preset time), the real-time speed of the fan can be detected, which is adjusted accurately according to the comparison result of the detected real-time speed and the target speed The current duty cycle of the driving voltage provides a basis, which can avoid the problem that the current duty cycle cannot be accurately adjusted due to the instability of the current duty cycle of the driving voltage.
[0054] According to an embodiment of the present invention, the detecting the real-time rotational speed of the brushless DC fan specifically includes: counting the number of pulses output by the brushless DC fan within a second preset time; and calculating the number of pulses according to the number of pulses. Describe the real-time speed.
[0055] According to the method for controlling the rotational speed of the brushless DC fan according to the embodiment of the present invention, the real-time speed of the fan can be accurately calculated according to the second preset time and the specific number of pulses output by the brushless DC fan within the second preset time. Rotating speed. In addition, the user can freely set the second preset time according to personal needs.
[0056] image 3 It shows a schematic structural diagram of a device for controlling the speed of a brushless DC fan according to an embodiment of the present invention.
[0057] Such as image 3 As shown, the device 300 for controlling the rotational speed of the brushless DC fan according to an embodiment of the present invention includes: a detection unit 302, which detects the real-time rotational speed of the brushless DC fan; and an adjustment unit 304, which compares the real-time rotational speed with the target rotational speed. The comparison is made, and according to the comparison result, the real-time speed is adjusted by adjusting the current duty ratio of the driving voltage of the brushless DC fan, so that the real-time speed matches the target speed.
[0058] According to the device 300 for controlling the rotation speed of the brushless DC fan according to the embodiment of the present invention, by increasing or decreasing the current duty ratio of the driving voltage of the fan according to the comparison result of the real-time rotation speed of the brushless DC fan and the target rotation speed, The output voltage of the fan is accurately controlled to achieve precise control of the fan speed, so that the real-time speed of the fan and the target speed of the fan have little deviation or the real-time speed is equal to the target speed (that is, the real-time speed matches the target speed), and when When the real-time speed matches the target speed, the noise of the refrigerator can be minimized.
[0059] According to an embodiment of the present invention, it further includes: a setting unit 306, which sets multiple difference intervals for the difference between the real-time rotation speed and the target rotation speed, and sets different duty cycles for the multiple difference intervals The adjustment amount; the storage unit 308 stores the difference interval and the duty cycle adjustment amount correspondingly.
[0060] According to the device 300 for controlling the rotation speed of a brushless DC fan according to an embodiment of the present invention, by setting a plurality of difference intervals according to the difference between the real-time rotation speed and the target rotation speed, and setting a corresponding duty cycle adjustment amount for each difference interval, After calculating the difference between the real-time speed and the target speed, the corresponding duty cycle adjustment value can be called according to the difference interval in which the difference is located, so as to realize the precise adjustment of the current duty cycle of the fan. Of course, in order to further improve the control accuracy of the fan speed, each difference interval and the duty cycle adjustment amount corresponding to each difference interval can be further refined, so that each difference interval is very small, and each difference interval The corresponding duty cycle adjustments are very accurate.
[0061] According to an embodiment of the present invention, the adjustment unit 304 is specifically configured to: when the comparison result is that the real-time rotation speed is greater than the target rotation speed, according to the difference between the real-time rotation speed and the target rotation speed. Value interval, call the duty cycle adjustment amount corresponding to the difference interval, and reduce the current duty cycle of the driving voltage by the duty cycle adjustment amount; when the comparison result is that the real-time speed is less than During the target rotation speed, according to the difference interval where the difference between the real-time rotation speed and the target rotation speed is located, the duty cycle adjustment amount corresponding to the difference interval is called, and the current duty cycle of the driving voltage Ratio increase the duty cycle adjustment amount.
[0062] According to the brushless DC fan speed control device 300 of the embodiment of the present invention, when the real-time speed is greater than the target speed, it means that the real-time speed is larger and the output voltage of the fan is higher. The current duty cycle is reduced by the duty cycle adjustment This can reduce the duty cycle of the driving voltage, thereby reducing the output voltage of the fan and the real-time speed of the fan, so that the real-time speed of the fan matches the target speed; similarly, when the real-time speed is less than the target speed, it means that the real-time speed is lower. The output voltage of the fan is low. By increasing the current duty cycle by the duty cycle adjustment amount, the duty cycle of the driving voltage can be increased, thereby increasing the output voltage of the fan and the real-time speed of the fan, so that the real-time The speed is matched with the target speed, and once the real-time speed of the fan matches the target speed, the noise of the refrigerator is very low, so as to minimize the noise of the refrigerator.
[0063] According to an embodiment of the present invention, the detection unit 302 includes: a judgment unit 3022, which judges whether the duration of the current duty cycle of the driving voltage is greater than or equal to a first preset time, and the detection unit 302 is configured to : When the judgment result is yes, start to detect the real-time speed of the brushless DC fan.
[0064] According to the device 300 for controlling the rotation speed of the brushless DC fan according to the embodiment of the present invention, since the current duty cycle of the driving voltage is unstable, there may be fluctuations. Therefore, when detecting the real-time rotation speed of the fan, the current Only when the duty cycle is stable (that is: the duration of the current duty cycle is greater than or equal to the first preset time), the real-time speed of the fan can be detected, which is accurate according to the comparison result of the detected real-time speed and the target speed Adjusting the current duty cycle of the driving voltage provides a basis, which can avoid the problem that the current duty cycle cannot be accurately adjusted due to the instability of the current duty cycle of the driving voltage.
[0065] According to an embodiment of the present invention, the detection unit 302 further includes: a statistics unit 3024, the number of pulses output by the brushless DC fan within the second preset time, and the real-time rotation speed is calculated according to the number of pulses .
[0066] According to the device 300 for controlling the rotational speed of the brushless DC fan according to the embodiment of the present invention, the fan's speed can be accurately calculated according to the second preset time and the specific number of pulses output by the brushless DC fan within the second preset time. Real-time speed. In addition, the user can freely set the second preset time according to personal needs.
[0067] Figure 4 It shows a schematic structural diagram of a brushless DC fan according to an embodiment of the present invention.
[0068] Such as Figure 4 As shown, the brushless DC fan 400 according to an embodiment of the present invention includes: a brushless DC fan speed control device 300, by using the brushless DC fan speed control device 300, precise control of the fan speed can be achieved , And ultimately achieve the greatest possible reduction in refrigerator noise.
[0069] Figure 5 A schematic structural diagram of a refrigerator according to an embodiment of the present invention is shown.
[0070] Such as Figure 5 As shown, a refrigerator 500 according to an embodiment of the present invention includes: a brushless DC fan 400. By installing the brushless DC fan 400 on the refrigerator 500, it is possible to accurately control the speed of the fan and reduce the refrigerator Noise, to achieve the purpose of reducing the noise of the refrigerator to the greatest extent.
[0071] Image 6 It shows a schematic structural diagram of a driving circuit of a brushless DC fan according to an embodiment of the present invention. Figure 7A with Figure 7B It shows a schematic flow chart of a method for controlling the speed of a brushless DC fan according to an embodiment of the present invention.
[0072] The following will combine Image 6 with Figure 7A with Figure 7B A detailed description of the method for controlling the speed of the brushless DC fan of the present invention includes:
[0073] Step 702, system initialization, allocation and Image 6 The timer in the control circuit connected to the drive circuit of the brushless DC fan shown ( Image 6 Not shown in), and initialize Image 6 The feedback I/O port in the driving circuit shown and Figure 5 Fan in ( Image 6 Not shown in), where the control circuit is located in the single-chip microcomputer, and one end is connected to Image 6 Is connected to the drive I/O port, and the other end is connected to Image 6 The feedback I/O port is connected, and the brushless DC fan is equipped with a Hall sensor. The Hall sensor enables the motor in the brushless DC fan to be commutated without brushes, but with electronics. , And can make the brushless DC fan output pulse through the feedback I/O port.
[0074] In step 704, it is determined whether the brushless DC fan has stopped rotating according to the operating status module in the brushless DC fan, if yes, step 706 is executed, and if not, step 708 is executed.
[0075] Step 706, when the brushless DC fan stops, adjust the duty cycle of PWM (Pulse Width Modulation) input from the drive I/O port connected to the single-chip microcomputer to 0 (that is, the current duty cycle of the drive voltage). The idle ratio is set to 0), and the output level of the brushless DC fan is set to low level.
[0076] Step 708, when the brushless DC fan is not stopped, set the current duty cycle of the PWM (the current duty of the driving voltage), and set the timer mode to the counting mode, so as to count Brush DC fan from Image 6 The number of pulses output by the feedback I/O port is shown.
[0077] Step 710: Determine whether the duration of the current duty cycle of the PWM is greater than the first preset time, and if the judgment result is yes, execute step 712; if the judgment result is no, execute step 710 again.
[0078] Step 712: The timer in the control circuit starts to read the number of pulses output from the feedback I/O port of the brushless DC fan in the second time, and calculates the real-time speed of the fan according to the number of pulses.
[0079] In step 714, the control circuit in the single-chip microcomputer determines whether the real-time rotation speed is lower than the target rotation speed, if yes, step 716 is executed, and if not, step 726 is executed.
[0080] In step 716, the control circuit judges whether the target rotation speed>real-time rotation speed+100 is established, if it is established, step 718 is executed; if it is not established, step 720 is executed.
[0081] In step 718, if the target rotation speed>real-time rotation speed+100, increase the current duty cycle of the PWM by M, which is usually 10%.
[0082] In step 720, when the target rotation speed ≤ the real-time rotation speed+100, it is judged whether the target rotation speed>the real-time rotation speed+20 is established, if it is established, the step 722 is executed; if it is not established, the step 724 is executed.
[0083] In step 722, if the target rotation speed>real-time rotation speed+20, increase the current duty cycle of the PWM by N, which is usually 1%.
[0084] Step 724: If the target speed ≤ real-time speed+20, it means that the deviation between the real-time speed and the target speed is reduced, and the noise of the refrigerator is small, so the current duty cycle of the PWM (that is, the current duty cycle of the driving voltage) remains unchanged .
[0085] Step 726: When the control circuit in the single-chip microcomputer judges that the real-time speed is greater than or equal to the target speed, the control circuit continues to judge whether the real-time speed>target speed+100 is established, if it is established, then go to step 728, if not, then go to step 730.
[0086] In step 728, if the real-time speed>target speed+100, it means that the real-time speed of the fan is too large and the noise of the refrigerator is too large. The current duty cycle of the PWM is reduced by M, which is usually 10%.
[0087] In step 730, when the real-time rotation speed ≤ the target rotation speed+100, it is determined whether the real-time rotation speed>the target rotation speed+20 is established, if it is established, then the step 732 is executed; if it is not established, the step 734 is executed.
[0088] In step 732, if the real-time rotation speed>target rotation speed+20, the current duty cycle of the PWM is reduced by N, which is usually 1%.
[0089] In step 734, if the real-time rotation speed ≤ the target rotation speed+20, it means that the deviation between the real-time rotation speed and the target rotation speed is reduced, the noise of the refrigerator is small, and the current duty cycle of the driving voltage is kept unchanged.
[0090] The technical scheme of the present invention is described in detail above in conjunction with the drawings, which can accurately control the duty cycle of the driving voltage of the fan, and then accurately control the output voltage of the fan, and finally realize the precise control of the fan speed and minimize the refrigerator The noise.
[0091] In the present invention, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0092] The above are only preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc., made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
