US20160123338A1 - Method for controlling fan start-up and fan - Google Patents
Method for controlling fan start-up and fan Download PDFInfo
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- US20160123338A1 US20160123338A1 US14/925,246 US201514925246A US2016123338A1 US 20160123338 A1 US20160123338 A1 US 20160123338A1 US 201514925246 A US201514925246 A US 201514925246A US 2016123338 A1 US2016123338 A1 US 2016123338A1
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- driving signal
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
- F04D27/001—Testing thereof; Determination or simulation of flow characteristics; Stall or surge detection, e.g. condition monitoring
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D19/00—Axial-flow pumps
- F04D19/002—Axial flow fans
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D25/00—Pumping installations or systems
- F04D25/02—Units comprising pumps and their driving means
- F04D25/06—Units comprising pumps and their driving means the pump being electrically driven
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
- F04D27/004—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids by varying driving speed
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/02—Stopping, starting, unloading or idling control
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/06—Control using electricity
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/20—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00 by changing the driving speed
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D17/00—Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps
- F04D17/08—Centrifugal pumps
- F04D17/16—Centrifugal pumps for displacing without appreciable compression
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/66—Combating cavitation, whirls, noise, vibration or the like; Balancing
- F04D29/661—Combating cavitation, whirls, noise, vibration or the like; Balancing especially adapted for elastic fluid pumps
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
- Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D10/00—Energy efficient computing, e.g. low power processors, power management or thermal management
Definitions
- the invention relates to a fan and a method for controlling fan start-up, in particular to a three-phase fan and a method for controlling a three-phase fan in the start-up stage.
- the NB system For saving energy of a NB system, the NB system is often switched between a sleep mode and a normal mode. Thus, the fan may frequently stop operating or restart to operate for different operation modes.
- obvious start-up noise usually occurs while the fan restart to operate from stopping operation.
- the reason for the start-up noise is that: when the fan restarts to operate, a driving signal with constant high energy is provided in the open loop control stage to obligately start the fan, and no feedback signal from any sensor is utilized to adjust the driving signal.
- the start-up noise depends on the energy of the driving signal.
- FIG. 1 is a schematic diagram showing the duty cycle, noise and rotational speed of the conventional fan in the start-up stage.
- the fan continuously increases its rotational speed according to the driving signal S so the noise becomes worsened.
- the driving signal S drives the fan for a time period T openloop namely the impeller of the fan is successfully rotated and the rotational speed of the fan reaches a target rotational speed
- the fan switches to a close loop control stage.
- a feedback signal from a detection circuit is utilized to adjust the signal value of the driving signal (i.e. the duty cycle decreases from A to A′), and the fan rotates at a target rotational speed.
- the target rotational speed for the fan is much lower than the threshold rotational speed for the open loop control stage so the overshoot of the fan rotational speed occurs in the start-up procedure and thus obvious start-up noise occurs.
- An aspect of the disclosure is to provide a fan and a method for controlling fan start-up with reduced noise.
- a method for controlling a fan in a fan start-up stage which includes a first time period and a second time period, comprises: during the first time period, continuously providing a first driving signal to drive the fan; and during the second time period, continuously providing a second driving signal to drive the fan; wherein, during the first time period the signal value of the first driving signal gradually decreases until being equal to the signal value of the second driving signal, and the signal value of the first driving signal is initially greater than the signal value of the second driving signal.
- the signal value of the second driving signal is an unchanged value.
- the fan comprises an impeller, a motor and a control circuit.
- the motor is connected to the impeller and drives the impeller to operate, and the motor is electrically connected to the control circuit.
- the control circuit comprises a control unit and a detection unit, and the detection unit detects the current phase or back emf of the motor to output a feedback signal to the control unit.
- the method further comprises: after completing the fan start-up stage, providing a third driving signal to drive the fan according to the feedback signal.
- the first driving signal, the second driving signal and the third driving signal are provided by the control unit.
- the first driving signal, the second driving signal and the third driving signal are PWM signals or DC voltage signals.
- the signal value of the first driving signal linearly decreases.
- the signal value of the first driving signal non-linearly decreases.
- the sum of the first time period and the second time period is constant.
- a fan comprises an impeller, a motor and a control circuit.
- the motor is connected to the impeller and drives the impeller to operate.
- the control circuit is electrically connected to the motor and comprises a control unit.
- the control unit provides a first driving signal and a second driving signal to drive the fan.
- the fan start-up stage includes a first time period and a second time period.
- the control unit continuously provides the first driving signal to drive the fan, and during the first time period the signal value of the first driving signal gradually decreases until being equal to the signal value of the second driving signal.
- the control unit continuously provides the second driving signal to drive the fan, and the signal value of the first driving signal is initially greater than the signal value of the second driving signal.
- the signal value of the second driving signal is an unchanged value.
- control circuit further comprises a detection unit which detects the current phase or back emf of the motor and outputs a feedback signal to the control unit. After completing the fan start-up stage, the control unit provides a third driving signal to drive the fan according to the feedback signal.
- the fan and the method for controlling fan start-up in the fan start-up stage, by gradually decreasing the energy of the first driving signal and by controlling the rotational speed of the fan with the second driving signal in the open loop control stage, the overshoot of the rotational speed of the fan occurs as little as possible. Therefore, the start-up noise is reduced and the start-up capability is robust so continuously outputting higher energy is not needed and the electrical energy is saved.
- FIG. 1 is a schematic diagram showing the duty cycle, noise and rotational speed of the conventional fan in the start-up stage
- FIG. 2 is a block diagram of the fan according to the embodiment
- FIG. 3A is a schematic diagram showing the duty cycle, noise and rotational speed according to the embodiment
- FIG. 3B to FIG. 3E are schematic diagrams of the first driving signal in FIG. 3A in different decrease modes
- FIG. 4 is a flow chart of the steps of the method for controlling start-up according to the embodiment.
- FIG. 5 is a control flow chart of the method for controlling start-up according to the embodiment.
- FIG. 2 is a block diagram of the fan according to the embodiment.
- FIG. 3A is a schematic diagram showing the duty cycle, noise and rotational speed according to the embodiment.
- FIG. 3B to FIG. 3E are schematic diagrams of the first driving signal S 1 in FIG. 3A in different decrease modes.
- the fan 20 comprises an impeller 21 , a motor 22 and a control circuit 23 .
- the motor 22 is a three-phase motor. It is connected to the impeller 21 and the electrically connected to the control circuit 23 , and drives the impeller 21 to operate for example to rotate according to the driving signal outputted by the control circuit 23 .
- the control circuit 23 comprises a control unit 231 and a detection unit 232 .
- the control unit 231 provides the driving signal to drive the impeller 21 .
- the detection unit 232 detects the current phase or back emf of the motor 22 , and sends a feedback signal to the control unit 231 .
- the control unit 231 adjusts the driving signal according to the feedback signal.
- the control unit 231 and the detection unit 232 may constitute the same element for example they are integrated in the same element.
- a variable output control is utilized.
- the control unit 231 continuously provides a first driving signal S 1 to drive the motor 22 to rotate the impeller 21 .
- the control unit 231 continuously provides a second driving signal S 2 to drive the impeller 21 .
- the signal value of the first driving signal S 1 has larger output energy and the output energy gradually decreases (the signal value decreases from B to B′).
- the signal value of the second driving signal S 2 is an unchanged output energy value (B′), and the signal value of the first driving signal S 1 initially at B is greater than the signal value of the second driving signal S 2 at B′.
- the final signal value of the first driving signal S 1 at B′ is equal to the initial signal value of the second driving signal S 2 at B′.
- the initial signal value of the first driving signal S 1 at B may be a minimum duty cycle for starting the fan 20
- the initial signal value of the second driving signal S 2 at B′ may be the minimum duty cycle for operating the fan 20 .
- the first driving signal S 1 and the second driving signal S 2 may be PWM signals or DC voltage signals.
- the signal values for the first driving signal S 1 and the second driving signal S 2 may be preset in the control unit 231 .
- the sum of the first time period T 1 and the second time period T 2 mentioned above is constant, namely the time period for open loop T in the open loop control stage (i.e. the fan start-up stage).
- the first time period T 1 and the second time period T 2 are within the open loop control stage.
- the close loop control stage is entered.
- the fan overshoot occurs as little as possible.
- the time period for open loop T may vary due to various types of fans.
- the designer should adjust the first time period T 1 , the second time period T 2 , and the sum of the first time period T 1 and the second time period T 2 (the time period for open loop T in the open loop control stage) depending on various types of fans so the fan 20 would stably operate in the fan start-up stage and the start-up noise caused by the fan 20 would occur as little as possible.
- the control unit 231 of the control circuit 23 begins to provide a third driving signal S 3 to drive the motor 22 to rotate the impeller 21 according to the feedback signal from the detection unit 232 .
- the signal value of the third driving signal S 3 may be greater than the signal value of the second driving signal S 2 (i.e. the third driving signal S 3 A in FIG. 3A ) or equal to the signal value of the second driving signal S 2 (i.e. the third driving signal S 3 in FIG. 3A ) or smaller than the signal value of the second driving signal S 2 (i.e. the third driving signal S 3 B in FIG.
- the designer may adjust it depending on demand.
- the close loop control stage is entered and the control unit 231 provides the third driving signal S 3 , which is the same with the second driving signal S 2 , to continuously drive the motor 22 to rotate the impeller 21 for a short time. Then, it adjusts the rotational speed according to the feedback signal outputted from the detection unit 232 .
- the signal value of the second driving signal S 2 (the open loop control stage) may slightly higher or slightly lower than the signal value of the third driving signal S 3 (the close loop control stage) to slightly change the rotational speed so as to reduce switching noise when switching control modes.
- the signal value of the first driving signal S 1 gradually decreases. For example, it may linearly decrease or non-linearly decrease, and the designer may adjust it depending on demand.
- the decrease of the first driving signal may refer to FIG. 3B to FIG. 3E which indicate the curve in linear decrease mode S 1 A (shown in FIG. 3B ), the curve in curved line decrease mode S 1 B (shown in FIG. 3C ), the curve in ladder decrease mode S 1 C (shown in FIG. 3D ), or the curve in combination mode of linear decrease and curved line decrease S 1 D (shown in FIG. 3E ).
- the curves S 1 A ⁇ S 1 D in the above mentioned decrease modes may be parabolas, hyperbolas or any curved lines to make the signal value of the first driving signal S 1 gradually decrease during the first time period T 1 .
- FIG. 4 is a flow chart of the steps of the method for controlling start-up according to the embodiment.
- the method is adapted to the control for the fan start-up stage.
- the fan start-up stage includes a first time period and a second time period.
- the method comprises at least the following steps of: during the first time period continuously providing a first driving signal to drive the fan (the step S 10 ); and during the second time period continuously providing a second driving signal to drive the fan; wherein during the first time period, the signal value of the first driving signal gradually decreases until the signal value of the first driving signal is equal to the signal value of the second driving signal.
- the signal value of the first driving signal is initially greater than the signal value of the second driving signal (the step S 20 ).
- the signal value of the first driving signal S 1 gradually decreases during the first time period T 1 . For example, it linearly decreases or non-linearly decreases, and the designer may adjust them depending on demand.
- the signal value of the second driving signal S 2 is an unchanged value.
- the signal value of the second driving signal S 2 may gradually decrease or gradually increase, and the designer may adjust it depending on demand.
- the length of the second time period T 2 may be adjusted depending on the stable operation duration of the fan. The designer may adjust it according to the required time for the fan to operate stably.
- the first driving signal S 1 and the second driving signal S 2 may be PWM signals or DC voltage signals, and the designer may adjust them depending on demand.
- the initial signal value B of the first driving signal S 1 is the minimum duty cycle for the fan 20 to start, namely the torque provided by the first driving signal S 1 on the fan needs to be greater than the torque caused by the maximum static friction on the fan 20 . Due to various kinds of fan structures, the maximum static friction on the fan 20 may be different.
- the initial signal value B′ of the second driving signal S 2 is the minimum duty cycle for the fan 20 to operate, namely the torque provided by the second driving signal S 2 on the fan needs to be greater than the torque caused by the kinetic friction during the operation of the fan 20 . Therefore, the first driving signal S 1 and the second driving signal S 2 should be adjusted depending on different fan structures and/or motors.
- FIG. 5 is a control flow chart of the method for controlling start-up according to the embodiment.
- the method is adapted to the control in the fan start-up stage.
- the control procedure of the method for controlling start-up comprises at least following steps: providing the first driving signal to drive the fan (the step S 100 ); determining whether the signal value of the first driving signal is equal to the signal value of the second driving signal (the step S 200 ). If not, decreasing the signal value of the first driving signal (the step S 300 ); if yes, providing the second driving signal to drive the fan (the step S 400 ); then determining whether the driving time reaches the time period for open loop (the step S 500 ).
- the first driving signal is provided to drive the fan.
- the step S 200 is performed. Namely, after the predefined time period, the method determines whether the signal value of the first driving signal is equal to the signal value of the second driving signal.
- step S 200 if the signal value of the first driving signal is not equal to the signal value of the second driving signal, then the step S 300 is performed. Namely, the signal value of the first driving signal is decreased, and then the step S 100 is performed to drive the fan with the decreased first driving signal after decreasing the signal value of the first driving signal. Besides, in the step S 200 , if the signal value of the first driving signal is equal to the signal value of the second driving signal, then the step S 400 is performed. Namely, the second driving signal is provided to drive the fan. Finally, the step S 500 is performed.
- step S 500 it is determined whether the time reaches the time period for open loop T. If the driving time reaches the time period for open loop T, the open loop control stage for the fan is complete and then the close loop control stage is entered; if the driving time does not reach the time period for open loop T, the step S 400 is performed.
- the signal value of the first driving signal S 1 gradually decreases during the first time period T 1 .
- the required time for the signal value of the first driving signal S 1 to decrease to the signal value of the second driving signal S 2 is the first time period T 1 mentioned above.
- the time period for open loop T (the sum of the first time period T 1 and the second time period T 2 ) is constant. Because the time period for open loop T is constant, the second time period T 2 is subsequent to the first time period T 1 , and then the second driving signal S 2 is continuously provided to drive the fan until reaching the time period for open loop T.
- the fan and the method for controlling fan start-up in the fan start-up stage, by gradually decreasing the energy of the first driving signal and by controlling the rotational speed of the fan with the second driving signal in the open loop control stage, the overshoot of the rotational speed of the fan occurs as little as possible. Therefore, the start-up noise is reduced and the start-up capability is robust so continuously outputting higher energy is not needed and the electrical energy is saved.
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Abstract
A method for controlling a fan in a fan start-up stage including a first time period and a second time period comprises the following steps of: during the first time period, continuously providing a first driving signal to drive the fan; and during the second time period, continuously providing a second driving signal to drive the fan; wherein, during the first time period the signal value (driving energy) of the first driving signal gradually decreases until being equal to the signal value of the second driving signal, and the signal value of the first driving signal is initially greater than the signal value of the second driving signal. A fan is also disclosed.
Description
- This application claims the priority benefits of U.S. provisional application Ser. No. 62/073,477, filed on Oct. 31, 2014 and Taiwan application serial No. 104132038, filed on Sep. 30, 2015. The entirety of the above-mentioned patent applications are hereby incorporated by references herein and made a part of specification.
- 1. Technical Field
- The invention relates to a fan and a method for controlling fan start-up, in particular to a three-phase fan and a method for controlling a three-phase fan in the start-up stage.
- 2. Related Art
- For saving energy of a NB system, the NB system is often switched between a sleep mode and a normal mode. Thus, the fan may frequently stop operating or restart to operate for different operation modes. However, obvious start-up noise usually occurs while the fan restart to operate from stopping operation. The reason for the start-up noise is that: when the fan restarts to operate, a driving signal with constant high energy is provided in the open loop control stage to obligately start the fan, and no feedback signal from any sensor is utilized to adjust the driving signal. However, the start-up noise depends on the energy of the driving signal.
- Referring to
FIG. 1 ,FIG. 1 is a schematic diagram showing the duty cycle, noise and rotational speed of the conventional fan in the start-up stage. The fan continuously increases its rotational speed according to the driving signal S so the noise becomes worsened. After the driving signal S drives the fan for a time period Topenloop namely the impeller of the fan is successfully rotated and the rotational speed of the fan reaches a target rotational speed, the fan switches to a close loop control stage. In other words, in this stage, a feedback signal from a detection circuit is utilized to adjust the signal value of the driving signal (i.e. the duty cycle decreases from A to A′), and the fan rotates at a target rotational speed. However, because the energy of the driving signal for the fan at the start-up stage is too large, the target rotational speed for the fan is much lower than the threshold rotational speed for the open loop control stage so the overshoot of the fan rotational speed occurs in the start-up procedure and thus obvious start-up noise occurs. - Therefore, a fan and a method for controlling fan start-up with reduced noise as much as possible are desirable.
- An aspect of the disclosure is to provide a fan and a method for controlling fan start-up with reduced noise.
- A method for controlling a fan in a fan start-up stage, which includes a first time period and a second time period, comprises: during the first time period, continuously providing a first driving signal to drive the fan; and during the second time period, continuously providing a second driving signal to drive the fan; wherein, during the first time period the signal value of the first driving signal gradually decreases until being equal to the signal value of the second driving signal, and the signal value of the first driving signal is initially greater than the signal value of the second driving signal.
- In one embodiment, the signal value of the second driving signal is an unchanged value.
- In one embodiment, the fan comprises an impeller, a motor and a control circuit. The motor is connected to the impeller and drives the impeller to operate, and the motor is electrically connected to the control circuit. The control circuit comprises a control unit and a detection unit, and the detection unit detects the current phase or back emf of the motor to output a feedback signal to the control unit. The method further comprises: after completing the fan start-up stage, providing a third driving signal to drive the fan according to the feedback signal.
- In one embodiment, the first driving signal, the second driving signal and the third driving signal are provided by the control unit.
- In one embodiment, the first driving signal, the second driving signal and the third driving signal are PWM signals or DC voltage signals.
- In one embodiment, the signal value of the first driving signal linearly decreases.
- In one embodiment, the signal value of the first driving signal non-linearly decreases.
- In one embodiment, the sum of the first time period and the second time period is constant.
- A fan comprises an impeller, a motor and a control circuit. The motor is connected to the impeller and drives the impeller to operate. The control circuit is electrically connected to the motor and comprises a control unit. In a fan start-up stage, the control unit provides a first driving signal and a second driving signal to drive the fan. The fan start-up stage includes a first time period and a second time period. During the first time period the control unit continuously provides the first driving signal to drive the fan, and during the first time period the signal value of the first driving signal gradually decreases until being equal to the signal value of the second driving signal. During the second time period the control unit continuously provides the second driving signal to drive the fan, and the signal value of the first driving signal is initially greater than the signal value of the second driving signal.
- In one embodiment, the signal value of the second driving signal is an unchanged value.
- In one embodiment, the control circuit further comprises a detection unit which detects the current phase or back emf of the motor and outputs a feedback signal to the control unit. After completing the fan start-up stage, the control unit provides a third driving signal to drive the fan according to the feedback signal.
- In summary, regarding the fan and the method for controlling fan start-up, in the fan start-up stage, by gradually decreasing the energy of the first driving signal and by controlling the rotational speed of the fan with the second driving signal in the open loop control stage, the overshoot of the rotational speed of the fan occurs as little as possible. Therefore, the start-up noise is reduced and the start-up capability is robust so continuously outputting higher energy is not needed and the electrical energy is saved.
- The embodiments will become more fully understood from the detailed description and accompanying drawings, which are given for illustration only, and thus are not limitative of the present invention, and wherein:
-
FIG. 1 is a schematic diagram showing the duty cycle, noise and rotational speed of the conventional fan in the start-up stage; -
FIG. 2 is a block diagram of the fan according to the embodiment; -
FIG. 3A is a schematic diagram showing the duty cycle, noise and rotational speed according to the embodiment; -
FIG. 3B toFIG. 3E are schematic diagrams of the first driving signal inFIG. 3A in different decrease modes; -
FIG. 4 is a flow chart of the steps of the method for controlling start-up according to the embodiment; and -
FIG. 5 is a control flow chart of the method for controlling start-up according to the embodiment. - The embodiments of the invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.
- Referring to
FIG. 2 andFIG. 3A toFIG. 3E .FIG. 2 is a block diagram of the fan according to the embodiment.FIG. 3A is a schematic diagram showing the duty cycle, noise and rotational speed according to the embodiment.FIG. 3B toFIG. 3E are schematic diagrams of the first driving signal S1 inFIG. 3A in different decrease modes. - Referring to
FIG. 2 , thefan 20 comprises animpeller 21, amotor 22 and acontrol circuit 23. Themotor 22 is a three-phase motor. It is connected to theimpeller 21 and the electrically connected to thecontrol circuit 23, and drives theimpeller 21 to operate for example to rotate according to the driving signal outputted by thecontrol circuit 23. Furthermore, thecontrol circuit 23 comprises acontrol unit 231 and adetection unit 232. Thecontrol unit 231 provides the driving signal to drive theimpeller 21. Thedetection unit 232 detects the current phase or back emf of themotor 22, and sends a feedback signal to thecontrol unit 231. Thus, in the close loop control stage, thecontrol unit 231 adjusts the driving signal according to the feedback signal. In other embodiments, thecontrol unit 231 and thedetection unit 232 may constitute the same element for example they are integrated in the same element. - To reduce start-up noise together with start-up capability, in the open loop control stage during the start-up procedure, a variable output control is utilized. Referring to
FIG. 2 andFIG. 3A , when theimpeller 21 restarts to operate from stop, in the open loop control stage during the first time period T1 thecontrol unit 231 continuously provides a first driving signal S1 to drive themotor 22 to rotate theimpeller 21. After theimpeller 21 is successfully rotated, in the open loop control stage during the second time period T2 thecontrol unit 231 continuously provides a second driving signal S2 to drive theimpeller 21. During the first time period T1, the signal value of the first driving signal S1 has larger output energy and the output energy gradually decreases (the signal value decreases from B to B′). The signal value of the second driving signal S2 is an unchanged output energy value (B′), and the signal value of the first driving signal S1 initially at B is greater than the signal value of the second driving signal S2 at B′. The final signal value of the first driving signal S1 at B′ is equal to the initial signal value of the second driving signal S2 at B′. The initial signal value of the first driving signal S1 at B may be a minimum duty cycle for starting thefan 20, and the initial signal value of the second driving signal S2 at B′ may be the minimum duty cycle for operating thefan 20. In the embodiment, the first driving signal S1 and the second driving signal S2 may be PWM signals or DC voltage signals. The signal values for the first driving signal S1 and the second driving signal S2 may be preset in thecontrol unit 231. - Besides, the sum of the first time period T1 and the second time period T2 mentioned above is constant, namely the time period for open loop T in the open loop control stage (i.e. the fan start-up stage). The first time period T1 and the second time period T2 are within the open loop control stage. After the time period for open loop T in the open loop control stage, the close loop control stage is entered. Thus, as shown in
FIG. 3A , while the rotational speed of theimpeller 21 gradually increases until the time reaches the time period for open loop T, the corresponding noise does not obviously become worsened. Because the signal value of the first driving signal S1 gradually decreases to the signal value of the second driving signal S2 (the signal value decreases from B to B′), the fan overshoot occurs as little as possible. Moreover, the time period for open loop T may vary due to various types of fans. Thus, the designer should adjust the first time period T1, the second time period T2, and the sum of the first time period T1 and the second time period T2 (the time period for open loop T in the open loop control stage) depending on various types of fans so thefan 20 would stably operate in the fan start-up stage and the start-up noise caused by thefan 20 would occur as little as possible. - After the
fan 20 stably operates, it enters or begins to operate in the close loop control stage (i.e. the regular operation stage). Here, thecontrol unit 231 of thecontrol circuit 23 begins to provide a third driving signal S3 to drive themotor 22 to rotate theimpeller 21 according to the feedback signal from thedetection unit 232. In the embodiment, the signal value of the third driving signal S3 may be greater than the signal value of the second driving signal S2 (i.e. the third driving signal S3A inFIG. 3A ) or equal to the signal value of the second driving signal S2 (i.e. the third driving signal S3 inFIG. 3A ) or smaller than the signal value of the second driving signal S2 (i.e. the third driving signal S3B inFIG. 3A ), and the designer may adjust it depending on demand. In other embodiments, after the second time period T2 ends (i.e. the open loop control stage ends), the close loop control stage is entered and thecontrol unit 231 provides the third driving signal S3, which is the same with the second driving signal S2, to continuously drive themotor 22 to rotate theimpeller 21 for a short time. Then, it adjusts the rotational speed according to the feedback signal outputted from thedetection unit 232. In other embodiments, the signal value of the second driving signal S2 (the open loop control stage) may slightly higher or slightly lower than the signal value of the third driving signal S3 (the close loop control stage) to slightly change the rotational speed so as to reduce switching noise when switching control modes. - In the embodiment, the signal value of the first driving signal S1 gradually decreases. For example, it may linearly decrease or non-linearly decrease, and the designer may adjust it depending on demand. The decrease of the first driving signal may refer to
FIG. 3B toFIG. 3E which indicate the curve in linear decrease mode S1A (shown inFIG. 3B ), the curve in curved line decrease mode S1B (shown inFIG. 3C ), the curve in ladder decrease mode S1C (shown inFIG. 3D ), or the curve in combination mode of linear decrease and curved line decrease S1D (shown inFIG. 3E ). The curves S1A˜S1D in the above mentioned decrease modes may be parabolas, hyperbolas or any curved lines to make the signal value of the first driving signal S1 gradually decrease during the first time period T1. - Referring to
FIG. 4 ,FIG. 4 is a flow chart of the steps of the method for controlling start-up according to the embodiment. The method is adapted to the control for the fan start-up stage. The fan start-up stage includes a first time period and a second time period. The method comprises at least the following steps of: during the first time period continuously providing a first driving signal to drive the fan (the step S10); and during the second time period continuously providing a second driving signal to drive the fan; wherein during the first time period, the signal value of the first driving signal gradually decreases until the signal value of the first driving signal is equal to the signal value of the second driving signal. The signal value of the first driving signal is initially greater than the signal value of the second driving signal (the step S20). - In the step S10, the signal value of the first driving signal S1 gradually decreases during the first time period T1. For example, it linearly decreases or non-linearly decreases, and the designer may adjust them depending on demand.
- Besides, in the step S20 in the embodiment, the signal value of the second driving signal S2 is an unchanged value. In other embodiments, the signal value of the second driving signal S2 may gradually decrease or gradually increase, and the designer may adjust it depending on demand. Moreover, the length of the second time period T2 may be adjusted depending on the stable operation duration of the fan. The designer may adjust it according to the required time for the fan to operate stably.
- In the embodiment, the first driving signal S1 and the second driving signal S2 may be PWM signals or DC voltage signals, and the designer may adjust them depending on demand. Moreover, the initial signal value B of the first driving signal S1 is the minimum duty cycle for the
fan 20 to start, namely the torque provided by the first driving signal S1 on the fan needs to be greater than the torque caused by the maximum static friction on thefan 20. Due to various kinds of fan structures, the maximum static friction on thefan 20 may be different. Besides, the initial signal value B′ of the second driving signal S2 is the minimum duty cycle for thefan 20 to operate, namely the torque provided by the second driving signal S2 on the fan needs to be greater than the torque caused by the kinetic friction during the operation of thefan 20. Therefore, the first driving signal S1 and the second driving signal S2 should be adjusted depending on different fan structures and/or motors. - Referring to
FIG. 5 ,FIG. 5 is a control flow chart of the method for controlling start-up according to the embodiment. The method is adapted to the control in the fan start-up stage. The control procedure of the method for controlling start-up comprises at least following steps: providing the first driving signal to drive the fan (the step S100); determining whether the signal value of the first driving signal is equal to the signal value of the second driving signal (the step S200). If not, decreasing the signal value of the first driving signal (the step S300); if yes, providing the second driving signal to drive the fan (the step S400); then determining whether the driving time reaches the time period for open loop (the step S500). - In the step S100, the first driving signal is provided to drive the fan. After a predefined time period, the step S200 is performed. Namely, after the predefined time period, the method determines whether the signal value of the first driving signal is equal to the signal value of the second driving signal.
- In the step S200, if the signal value of the first driving signal is not equal to the signal value of the second driving signal, then the step S300 is performed. Namely, the signal value of the first driving signal is decreased, and then the step S100 is performed to drive the fan with the decreased first driving signal after decreasing the signal value of the first driving signal. Besides, in the step S200, if the signal value of the first driving signal is equal to the signal value of the second driving signal, then the step S400 is performed. Namely, the second driving signal is provided to drive the fan. Finally, the step S500 is performed.
- In the step S500, it is determined whether the time reaches the time period for open loop T. If the driving time reaches the time period for open loop T, the open loop control stage for the fan is complete and then the close loop control stage is entered; if the driving time does not reach the time period for open loop T, the step S400 is performed.
- In the embodiment, the signal value of the first driving signal S1 gradually decreases during the first time period T1. The required time for the signal value of the first driving signal S1 to decrease to the signal value of the second driving signal S2 is the first time period T1 mentioned above. Besides, since the sum of the first time period T1 and the second time period T2 mentioned above is constant, the time period for open loop T (the sum of the first time period T1 and the second time period T2) is constant. Because the time period for open loop T is constant, the second time period T2 is subsequent to the first time period T1, and then the second driving signal S2 is continuously provided to drive the fan until reaching the time period for open loop T.
- In summary, regarding the fan and the method for controlling fan start-up, in the fan start-up stage, by gradually decreasing the energy of the first driving signal and by controlling the rotational speed of the fan with the second driving signal in the open loop control stage, the overshoot of the rotational speed of the fan occurs as little as possible. Therefore, the start-up noise is reduced and the start-up capability is robust so continuously outputting higher energy is not needed and the electrical energy is saved.
- Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the invention.
Claims (10)
1. A method for controlling a fan in a fan start-up stage including a first time period and a second time period, comprising:
during the first time period, continuously providing a first driving signal to drive the fan; and
during the second time period, continuously providing a second driving signal to drive the fan;
wherein, during the first time period the signal value of the first driving signal gradually decreases until being equal to the signal value of the second driving signal, and the signal value of the first driving signal is initially greater than the signal value of the second driving signal.
2. The method of claim 1 , wherein the signal value of the second driving signal is an unchanged value.
3. The method of claim 1 , wherein the fan comprises an impeller, a motor and a control circuit, the motor is connected to the impeller and drives the impeller to operate, the motor is electrically connected to the control circuit, the control circuit comprises a control unit and a detection unit, the detection unit detects the current phase or back emf of the motor to output a feedback signal to the control unit, the method further comprises:
after completing the fan start-up stage, providing a third driving signal to drive the fan according to the feedback signal.
4. The method of claim 3 , wherein the first driving signal, the second driving signal and the third driving signal are provided by the control unit.
5. The method of claim 3 , wherein the first driving signal, the second driving signal and the third driving signal are PWM signals or DC voltage signals.
6. The method of claim 1 , wherein the signal value of the first driving signal linearly decreases or non-linearly decreases.
7. The method of claim 1 , wherein the sum of the first time period and the second time period is constant.
8. A fan, comprising:
an impeller;
a motor, connected to the impeller and drive the impeller to operate; and
a control circuit, electrically connected to the motor, comprising:
a control unit, in a fan start-up stage providing a first driving signal and a second driving signal to drive the fan;
wherein, the fan start-up stage includes a first time period and a second time period,
during the first time period the control unit continuously provides the first driving signal to drive the fan, and during the first time period the signal value of the first driving signal gradually decreases until being equal to the signal value of the second driving signal,
during the second time period the control unit continuously provides the second driving signal to drive the fan, and the signal value of the first driving signal is initially greater than the signal value of the second driving signal.
9. The fan of claim 8 , wherein the signal value of the second driving signal is an unchanged value.
10. The fan of claim 8 , wherein the control circuit further comprises:
a detection unit, detecting the current phase or back emf of the motor and outputting a feedback signal to the control unit,
wherein after completing the fan start-up stage, the control unit provides a third driving signal to drive the fan according to the feedback signal.
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
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US14/925,246 US20160123338A1 (en) | 2014-10-31 | 2015-10-28 | Method for controlling fan start-up and fan |
US16/524,814 US11473584B2 (en) | 2014-10-31 | 2019-07-29 | Method of starting a fan using an open loop starting stage with a decreasing drive signal value |
US17/871,504 US11933309B2 (en) | 2014-10-31 | 2022-07-22 | Method of starting a fan using an open loop starting stage with a decreasing drive signal value |
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US201462073477P | 2014-10-31 | 2014-10-31 | |
TW104132038A TWI576693B (en) | 2014-10-31 | 2015-09-30 | Start-control method of fan and fan |
TW104132038 | 2015-09-30 | ||
US14/925,246 US20160123338A1 (en) | 2014-10-31 | 2015-10-28 | Method for controlling fan start-up and fan |
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US16/524,814 Continuation US11473584B2 (en) | 2014-10-31 | 2019-07-29 | Method of starting a fan using an open loop starting stage with a decreasing drive signal value |
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US14/925,246 Abandoned US20160123338A1 (en) | 2014-10-31 | 2015-10-28 | Method for controlling fan start-up and fan |
US16/524,814 Active 2036-03-29 US11473584B2 (en) | 2014-10-31 | 2019-07-29 | Method of starting a fan using an open loop starting stage with a decreasing drive signal value |
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GB2578615B (en) * | 2018-11-01 | 2021-10-13 | Dyson Technology Ltd | A fan assembly |
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US11473584B2 (en) | 2022-10-18 |
US20190353170A1 (en) | 2019-11-21 |
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