Fan with automated balance control to minimize oscillation and related methods

Abstract

A fan includes a motor, a rotatable hub coupled to the motor, and a plurality of fan blades coupled to the hub for generating airflow when rotated by the motor at a plurality of different fan speeds. A sensor is configured to sense an acceleration value associated with the fan at the plurality of fan speeds, including a desired fan speed selected by a user. A controller is configured to automatically select an operating fan speed for the motor corresponding to one of the plurality of fan speeds having a minimum acceleration value as the desired fan speed. Related methods are also disclosed.

Description

[0001] This application is a continuation of U.S. Patent Application No. 17 / 315,904, filed May 10, 2021, which claims the benefit of U.S. Provisional Patent Application Ser. No. 63 / 021,854, filed May 8, 2020, the disclosure of which is incorporated herein by reference. The disclosure of U.S. Patent No. 8,123,479 is incorporated herein by reference. TECHNICAL FIELD

[0002] This application relates generally to the fan art and, more particularly, to a fan adapted to determine a particular fan speed having a minimum oscillation based on a user-inputted fan speed and operate the fan accordingly so as to dynamically eliminate undesirable oscillations. BACKGROUND

[0003] Fans, such as overhead or ceiling fans in the vernacular, may experience a certain degree of oscillation or wobbling during use. Due to imbalance, improper installation or other environmental conditions, such as wind, such fans in use can experience undesirable oscillation, such as extreme wobbling. Eliminating this undesirable oscillation is beneficial, as it may lead to improved efficiency, increased service life, reduced noise, and an overall increase in consumer satisfaction with fan performance.

[0004] Fans are also capable of operating at different speeds with varying degrees of oscillation or wobbling. Although some degree of oscillation or wobbling is common, typically certain speeds promote wobbling more than other speeds. Others in the past have recognized the problem, but the primarily solution was to pre-program the fan so as to avoid such undesirable operating conditions. While helpful, this may fail to account for imbalance problems encountered during later use.

[0005] Accordingly, a need is identified for a fan having the ability to dynamically control its operation to eliminate or reduce undesirable oscillations, or wobble, such that some or all of the foregoing limitations are overcome, or perhaps others yet to be discovered.SUMMARY

[0006] According to a first aspect of the disclosure, a fan includes a motor, a hub coupled to the motor, and a plurality of fan blades coupled to the hub. A sensor is configured to sense an acceleration value associated with the fan at each of a plurality of fan speeds. A controller is configured to automatically select an operating speed for the motor corresponding to one of the plurality of fan speeds having a minimum acceleration value.

[0007] In one embodiment, the fan comprises a ceiling fan, and the sensor comprises an accelerometer. In particular, the accelerometer may comprise a three-axis, capacitance-based accelerometer. The accelerometer may be configured to sense an acceleration measurement associated with the fan on three axes. The sensor or accelerometer may be controlled to sense the acceleration value associated with the fan at the plurality of fan speeds at a predefined interval.

[0008] A user input may be provided to input a desired or selected fan speed to the controller. The plurality of fan speeds include at least three fan speeds, including the desired fan speed, a first speed lower than the desired fan speed and a second speed higher than the desired fan speed, and the controller may select the fan speed causing the lowest amount of acceleration. The controller may monitor an actual fan operating speed to be within a predefined range of the desired fan speed, and may be configured to automatically adjust the desired fan speed to the operating speed. The controller may also be configured to store the operating speed as a replacement value for the desired fan speed.

[0009] A further aspect of the disclosure pertains to a method of operating a fan at a minimum oscillation within a range of fan speeds including a desired fan speed inputted by a user. The method comprises measuring an acceleration value at the desired fan speed, a first fan speed less than the desired speed, and a second fan speed greater than the desired fan speed. The method further comprises selecting one of the desired fan speed, first fan speed and second fan speed having the lowest acceleration value as a selected fan speed. Still further, the method comprises operating the fan at the selected fan speed.

[0010] In one embodiment, the method comprises monitoring the selected fan speed so as to be within a predefined range. The method may further comprise automatically operating the fan at the selected fan speed when the desired speed is inputted. Still further, the method may include the step of calculating the first fan speed and the second fan speed.

[0011] Yet a further aspect of the disclosure pertains to a method of programming a fan operable at a plurality of fan speeds. The method comprises finding which of the plurality of fan speeds has a minimum oscillation value. Still further, the method comprises programming the fan to operate at the fan speed corresponding to the minimum oscillation value.

[0012] In one embodiment, the programming step comprises selecting or saving the fan speed as corresponding to a user-inputted fan speed. The step of measuring an oscillation value may comprise checking accelerometer data for the fan at each of the plurality of fan speeds. The measuring step may further comprise measuring an acceleration value at a desired fan speed, a first fan speed less than the desired speed, and a second fan speed greater than the desired fan speed. The determining step may comprise selecting one of the desired fan speed, first fan speed and second fan speed with the lowest acceleration value as the selected fan speed.BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0013] The accompanying drawings incorporated in and forming a part of the specification, illustrate several aspects of this disclosure, and together with the description serve to explain the principles of the disclosure. In the drawings:

[0014] FIG. 1 shows an exemplary fan and the control arrangement according to one aspect of the disclosure;

[0015] FIG. 2 is a graph showing the acceleration data determined by a sensor, such as an accelerometer, across a range of fan speeds; and

[0016] FIG. 3 is a flow chart illustrating a process flow according to one aspect of the disclosure.DETAILED DESCRIPTION

[0017] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and like numerals represent like details in the various figures. Also, it is to be understood that other embodiments may be utilized, and that process or other changes may be made without departing from the scope of the disclosure. The following detailed description is not to be taken in a limiting sense, and the scope of the invention is defined only by the appended claims and their equivalents.

[0018] As shown in FIG. 1, a representative fan, such as an overhead ceiling fan 10 is illustrated. The fan 10 is coupled with the ceiling C and suspended over the floor F. The fan 10 includes a support 20, which may be adapted to be directly coupled with the ceiling.

[0019] The fan 10 also includes a motor 30, such as a permanent magnet (AC) motor, but it should be appreciated that other types of motors may be utilized, including for example an induction motor or the like. The motor 30 is connected to or in communication with a rotatable hub 40 that is rotated by the motor. A plurality of fan blades 50 extend radially outwardly from the hub 40, and may comprise any desired length, width, or cross-sectional shape.

[0020] The fan 10 further includes a sensor configured for detecting lateral or orbital oscillation, wobbling, or similar movement. In particular, the sensor may comprise an accelerometer 60. In one particular example, a three-axis capacitance-based accelerometer 60 is used. The accelerometer 60 may be internal to the fan, i.e., within a housing of the motor 30. Alternatively, the accelerometer 60 may be attached to any other suitable component of the fan 10, and sensors other than accelerometers may be used, such as for example a strain gage, load cell, or the like.

[0021] The fan also includes a controller 70 in communication with the motor 30. This motor controller 70 is configured to generate signals to both cause rotation at a speed and read a speed of the motor 30. The controller 70 may provide a spectrum of speeds, usually at pre-determined levels, at which the hub 40 may be rotated by the motor 30.

[0022] A control board may be configured for controlling the motor controller 70 and the accelerometer 60 via a software or control algorithm. The control board may comprise a microcontroller 80, which may be part of or otherwise in communication with the motor controller 70. The control board or microcontroller 80 may provide data, information, or instructions to command the operation of the fan 10 to achieve the desired speed functionality.

[0023] As noted above, the fan 10 is capable of operating at various speed settings, which may be pre-programmed and / or inputted by a user via a user input, i.e., a wall mounted controller or remote control 90 (wired or wireless, and possibly a mobile or handheld computer running an application adapted to provide information to controller 70 for controlling the speed of the fan 10). The user input allows the user to input or adjust speed settings of the fan 10, such as to select from a desired, discrete pre-defined speed, or select a desired speed from a substantially continuous range of speeds.

[0024] Based upon the output of the sensor, such as accelerometer 60, the controller 70 may detect and intelligently avoid certain speed settings wherein the detected wobble is greater than the detected wobble at adjacent speed settings. Alternatively, based upon the readings sensed by the sensor (accelerometer 60), the controller 70 may detect unduly high or extreme wobbling due to increased oscillations or accelerations sustained for a predetermined period of time and automatically stop the fan 10 from rotating, such as for example by stopping the motor or applying a brake.

[0025] As graphically illustrated in FIG. 2, various fan speeds may be associated with high wobble, which indicate resonance zones that the controller 70 seeks to avoid during operation of the fan 10. The detected speed settings that should be avoided may be detected via an initial pre-scan of the fan 10, such as during the manufacturing or commissioning process. When one or more particular speed settings is detected as having a high or otherwise undesirable wobble in the initial pre-scan, the speed setting(s) may be blocked or “blacklisted.” In other words, the particular speed setting is placed on a list of speed settings for the fan 10 that are automatically bypassed from those selectable by the user, which list is created by the controller 70. Alternatively, the controller 70 may dynamically search (during operation of the fan) for nearby speeds that minimize wobble.

[0026] The accelerometer 60 may obtain oscillation or acceleration measurements on three axes, i.e., the X, Y, and Z axes. Generally, an accelerometer measures proper acceleration, which is the acceleration experienced in freefall, which is most commonly called “G-Force” (G). These oscillation or acceleration measurements are translated from voltages into milliGs (mG) before they are read by the microcontroller. Any further processing is performed based on the mG values. The accelerometer 60 is configured to take measurements upon defined intervals and store the measurements in a buffer containing the most recent thirty-two (32) values. For example, the accelerometer may take the measurements every twenty milliseconds (ms).

[0027] A memory buffer may be provided for each axis such that a plurality (e.g., a total of ninety-six (96)) values or measurements taken by the accelerometer may be stored at one time. When the microcontroller 80 queries the accelerometer 60 for its readings or measurements, the buffer is automatically emptied so that the newest measurements are then stored.

[0028] The microcontroller 80 may filter the readings. For example, the microcontroller 80 may utilize a low pass (“Butterworth”) filter to attenuate high frequency readings. This type of filter is a signal processing filter designed to have a frequency response as flat as possible in the passband, i.e., a maximally flat magnitude filter, and may be implemented in the software associated with the microcontroller 80.

[0029] The output from the filter is averaged using an exponential moving average algorithm. The resulting average from each of the three axes is the acceleration measurement used to select the minimum acceleration within a range of speeds. The microcontroller 80 then sends the determined speed (having the minimum acceleration) to the motor controller 70, which in turns commands the motor 30 to operate the fan 10 at the determined speed.

[0030] Turning to FIG. 3, a possible flow of the automatic balance control is illustrated. In this example, when the fan 10 is inputted or commanded to change speed to a user-desired or commanded speed by any means except the controller, i.e., either manually by a user or automatically based upon a pre-determined setting, the fan 10 such as via the controller 70 (or microcontroller 80) calculates or determines a plurality of fan speeds corresponding to the commanded speed. For example, the calculation may be to determine of three (3) speeds, one just below the inputted or commanded speed (SC-1), the inputted or commanded speed (SC), and one just above the inputted or commanded speed (SC+1).

[0031] The automated balancing process then involves analyzing the acceleration data at the inputted speed (SC) as well as two nearby speeds (one below and one above the inputted speed (SC)) to determine whether the nearby speeds have less wobble than the inputted speed (SC). The actual or determined speed of the fan is then selected as the speed having the lowest acceleration measured of the three speeds (SC, SC-1, SC+1).

[0032] The actual fan speed (Sactual) is then checked periodically at defined intervals to ascertain whether the actual speed (Sactual) is within a predefined range of the commanded speed (SC). The predefined range may be defined as a range starting at half the distance from the lowest calculated speed (SCmin) to the commanded speed (SC) and ending at half the distance between the commanded speed (SC) and the uppermost calculated speed (SCmax). Once the actual fan speed (Sactual) is within the predefined range of the commanded speed (SC), a timer is started for a certain time to ensure steady state operation, such as forty (40) seconds.

[0033] At the expiration of the predefined time, another acceleration measurement is taken by the accelerometer 60 and saved as the acceleration value for that speed. The motor 30 is commanded by the controller 70 to operate the fan 10 at the lowest speed of the three previously calculated speeds. The process of checking the acceleration for this speed and the highest calculated speed is then repeated. The speed with the lowest acceleration or oscillation is chosen and saved.

[0034] If the fan 10 is inputted or commanded to the original speed again by a user, which would result in undesirable wobbling, the fan speed is automatically adjusted to the saved speed for that inputted or commanded speed. In other words, the inputted speed (determined to have an impermissible wobble) is automatically bypassed such that the fan operates at a nearby speed having a more desirable operating condition in terms of balance.

[0035] In another embodiment, the process involves analyzing the acceleration data collected by the accelerometer within a range of speeds. For example, if a user selects a speed that is 50% of the maximum speed of the fan, the process determines the minimum acceleration or oscillation between a range, such as 45% and 55%, of the maximum speed of the fan.  In other words, the process finds the minimum acceleration or oscillation within this particular range of speeds.  Based upon the acceleration detected by the accelerometer at each of the speeds, the controller 70 automatically selects the fan speed with the minimum acceleration within the range of speeds to minimize wobble.

[0036] Advantageously, the fan 10 with automated balance control is adaptable to unique installations and increases customer satisfaction. Wobbling may be automatically reduced or eliminated in real time without the need for intervention by the user or a maintenance technician. Such automated balance control increases the life of the fan 10 by protecting it from damage to itself or nearby structures.

[0037] As used herein, the following terms have the following meanings:

[0038] “A”, “an”, and “the” as used herein refers to both singular and plural referents unless the context clearly dictates otherwise. By way of example, “a compartment” refers to one or more than one compartment.

[0039] “About,”“substantially,”“generally” or “approximately,” as used herein referring to a measurable value, such as a parameter, an amount, a temporal duration, and the like, is meant to encompass variations of + / - 20% or less, preferably + / -10% or less, more preferably + / -5% or less, even more preferably + / -1% or less, and still more preferably + / -0.1% or less of and from the specified value, in so far such variations are appropriate to perform in the disclosed invention. However, it is to be understood that the value to which the modifier “about” refers is itself also specifically disclosed.

[0040] “Comprise”, “comprising”, “comprises” and “comprised of” as used herein are synonymous with “include”, “including”, “includes” or “contain”, “containing”, “contains” and are inclusive or open-ended terms that specifies the presence of what follows, e.g., such does not exclude or preclude the presence of additional, non-recited components, features, element, members, steps, known in the art or disclosed therein.

[0041] While certain embodiments have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. For example, while overhead fans of the type shown tend to be more susceptible to oscillation, the disclosed techniques may be applied to any type of fan, without limitation, including for instance pedestal fans, ventilating fans, directional fans, or the like. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the protection under the applicable law and that methods and structures within the scope of these claims and their equivalents be covered thereby.

Examples

Embodiment Construction

[0017] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and like numerals represent like details in the various figures. Also, it is to be understood that other embodiments may be utilized, and that process or other changes may be made without departing from the scope of the disclosure. The following detailed description is not to be taken in a limiting sense, and the scope of the invention is defined only by the appended claims and their equivalents.

[0018]As shown in FIG. 1, a representative fan, such as an overhead ceiling fan 10 is illustrated. The fan 10 is coupled with the ceiling C and suspended over the floor F. The fan 10 includes a support 20, which may be adapted to be directly coupled...

[0001] This application is a continuation of U.S. Patent Application No. 17 / 315,904, filed May 10, 2021, which claims the benefit of U.S. Provisional Patent Application Ser. No. 63 / 021,854, filed May 8, 2020, the disclosure of which is incorporated herein by reference. The disclosure of U.S. Patent No. 8,123,479 is incorporated herein by reference. TECHNICAL FIELD

[0002] This application relates generally to the fan art and, more particularly, to a fan adapted to determine a particular fan speed having a minimum oscillation based on a user-inputted fan speed and operate the fan accordingly so as to dynamically eliminate undesirable oscillations. BACKGROUND

[0003] Fans, such as overhead or ceiling fans in the vernacular, may experience a certain degree of oscillation or wobbling during use. Due to imbalance, improper installation or other environmental conditions, such as wind, such fans in use can experience undesirable oscillation, such as extreme wobbling. Eliminating this undesirable oscillation is beneficial, as it may lead to improved efficiency, increased service life, reduced noise, and an overall increase in consumer satisfaction with fan performance.

[0004] Fans are also capable of operating at different speeds with varying degrees of oscillation or wobbling. Although some degree of oscillation or wobbling is common, typically certain speeds promote wobbling more than other speeds. Others in the past have recognized the problem, but the primarily solution was to pre-program the fan so as to avoid such undesirable operating conditions. While helpful, this may fail to account for imbalance problems encountered during later use.

[0005] Accordingly, a need is identified for a fan having the ability to dynamically control its operation to eliminate or reduce undesirable oscillations, or wobble, such that some or all of the foregoing limitations are overcome, or perhaps others yet to be discovered.SUMMARY

[0006] According to a first aspect of the disclosure, a fan includes a motor, a hub coupled to the motor, and a plurality of fan blades coupled to the hub. A sensor is configured to sense an acceleration value associated with the fan at each of a plurality of fan speeds. A controller is configured to automatically select an operating speed for the motor corresponding to one of the plurality of fan speeds having a minimum acceleration value.

[0007] In one embodiment, the fan comprises a ceiling fan, and the sensor comprises an accelerometer. In particular, the accelerometer may comprise a three-axis, capacitance-based accelerometer. The accelerometer may be configured to sense an acceleration measurement associated with the fan on three axes. The sensor or accelerometer may be controlled to sense the acceleration value associated with the fan at the plurality of fan speeds at a predefined interval.

[0008] A user input may be provided to input a desired or selected fan speed to the controller. The plurality of fan speeds include at least three fan speeds, including the desired fan speed, a first speed lower than the desired fan speed and a second speed higher than the desired fan speed, and the controller may select the fan speed causing the lowest amount of acceleration. The controller may monitor an actual fan operating speed to be within a predefined range of the desired fan speed, and may be configured to automatically adjust the desired fan speed to the operating speed. The controller may also be configured to store the operating speed as a replacement value for the desired fan speed.

[0009] A further aspect of the disclosure pertains to a method of operating a fan at a minimum oscillation within a range of fan speeds including a desired fan speed inputted by a user. The method comprises measuring an acceleration value at the desired fan speed, a first fan speed less than the desired speed, and a second fan speed greater than the desired fan speed. The method further comprises selecting one of the desired fan speed, first fan speed and second fan speed having the lowest acceleration value as a selected fan speed. Still further, the method comprises operating the fan at the selected fan speed.

[0010] In one embodiment, the method comprises monitoring the selected fan speed so as to be within a predefined range. The method may further comprise automatically operating the fan at the selected fan speed when the desired speed is inputted. Still further, the method may include the step of calculating the first fan speed and the second fan speed.

[0011] Yet a further aspect of the disclosure pertains to a method of programming a fan operable at a plurality of fan speeds. The method comprises finding which of the plurality of fan speeds has a minimum oscillation value. Still further, the method comprises programming the fan to operate at the fan speed corresponding to the minimum oscillation value.

[0012] In one embodiment, the programming step comprises selecting or saving the fan speed as corresponding to a user-inputted fan speed. The step of measuring an oscillation value may comprise checking accelerometer data for the fan at each of the plurality of fan speeds. The measuring step may further comprise measuring an acceleration value at a desired fan speed, a first fan speed less than the desired speed, and a second fan speed greater than the desired fan speed. The determining step may comprise selecting one of the desired fan speed, first fan speed and second fan speed with the lowest acceleration value as the selected fan speed.BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0013] The accompanying drawings incorporated in and forming a part of the specification, illustrate several aspects of this disclosure, and together with the description serve to explain the principles of the disclosure. In the drawings:

[0014] FIG. 1 shows an exemplary fan and the control arrangement according to one aspect of the disclosure;

[0015] FIG. 2 is a graph showing the acceleration data determined by a sensor, such as an accelerometer, across a range of fan speeds; and

[0016] FIG. 3 is a flow chart illustrating a process flow according to one aspect of the disclosure.DETAILED DESCRIPTION

[0017] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and like numerals represent like details in the various figures. Also, it is to be understood that other embodiments may be utilized, and that process or other changes may be made without departing from the scope of the disclosure. The following detailed description is not to be taken in a limiting sense, and the scope of the invention is defined only by the appended claims and their equivalents.

[0018] As shown in FIG. 1, a representative fan, such as an overhead ceiling fan 10 is illustrated. The fan 10 is coupled with the ceiling C and suspended over the floor F. The fan 10 includes a support 20, which may be adapted to be directly coupled with the ceiling.

[0019] The fan 10 also includes a motor 30, such as a permanent magnet (AC) motor, but it should be appreciated that other types of motors may be utilized, including for example an induction motor or the like. The motor 30 is connected to or in communication with a rotatable hub 40 that is rotated by the motor. A plurality of fan blades 50 extend radially outwardly from the hub 40, and may comprise any desired length, width, or cross-sectional shape.

[0020] The fan 10 further includes a sensor configured for detecting lateral or orbital oscillation, wobbling, or similar movement. In particular, the sensor may comprise an accelerometer 60. In one particular example, a three-axis capacitance-based accelerometer 60 is used. The accelerometer 60 may be internal to the fan, i.e., within a housing of the motor 30. Alternatively, the accelerometer 60 may be attached to any other suitable component of the fan 10, and sensors other than accelerometers may be used, such as for example a strain gage, load cell, or the like.

[0021] The fan also includes a controller 70 in communication with the motor 30. This motor controller 70 is configured to generate signals to both cause rotation at a speed and read a speed of the motor 30. The controller 70 may provide a spectrum of speeds, usually at pre-determined levels, at which the hub 40 may be rotated by the motor 30.

[0022] A control board may be configured for controlling the motor controller 70 and the accelerometer 60 via a software or control algorithm. The control board may comprise a microcontroller 80, which may be part of or otherwise in communication with the motor controller 70. The control board or microcontroller 80 may provide data, information, or instructions to command the operation of the fan 10 to achieve the desired speed functionality.

[0023] As noted above, the fan 10 is capable of operating at various speed settings, which may be pre-programmed and / or inputted by a user via a user input, i.e., a wall mounted controller or remote control 90 (wired or wireless, and possibly a mobile or handheld computer running an application adapted to provide information to controller 70 for controlling the speed of the fan 10). The user input allows the user to input or adjust speed settings of the fan 10, such as to select from a desired, discrete pre-defined speed, or select a desired speed from a substantially continuous range of speeds.

[0024] Based upon the output of the sensor, such as accelerometer 60, the controller 70 may detect and intelligently avoid certain speed settings wherein the detected wobble is greater than the detected wobble at adjacent speed settings. Alternatively, based upon the readings sensed by the sensor (accelerometer 60), the controller 70 may detect unduly high or extreme wobbling due to increased oscillations or accelerations sustained for a predetermined period of time and automatically stop the fan 10 from rotating, such as for example by stopping the motor or applying a brake.

[0025] As graphically illustrated in FIG. 2, various fan speeds may be associated with high wobble, which indicate resonance zones that the controller 70 seeks to avoid during operation of the fan 10. The detected speed settings that should be avoided may be detected via an initial pre-scan of the fan 10, such as during the manufacturing or commissioning process. When one or more particular speed settings is detected as having a high or otherwise undesirable wobble in the initial pre-scan, the speed setting(s) may be blocked or “blacklisted.” In other words, the particular speed setting is placed on a list of speed settings for the fan 10 that are automatically bypassed from those selectable by the user, which list is created by the controller 70. Alternatively, the controller 70 may dynamically search (during operation of the fan) for nearby speeds that minimize wobble.

[0026] The accelerometer 60 may obtain oscillation or acceleration measurements on three axes, i.e., the X, Y, and Z axes. Generally, an accelerometer measures proper acceleration, which is the acceleration experienced in freefall, which is most commonly called “G-Force” (G). These oscillation or acceleration measurements are translated from voltages into milliGs (mG) before they are read by the microcontroller. Any further processing is performed based on the mG values. The accelerometer 60 is configured to take measurements upon defined intervals and store the measurements in a buffer containing the most recent thirty-two (32) values. For example, the accelerometer may take the measurements every twenty milliseconds (ms).

[0027] A memory buffer may be provided for each axis such that a plurality (e.g., a total of ninety-six (96)) values or measurements taken by the accelerometer may be stored at one time. When the microcontroller 80 queries the accelerometer 60 for its readings or measurements, the buffer is automatically emptied so that the newest measurements are then stored.

[0028] The microcontroller 80 may filter the readings. For example, the microcontroller 80 may utilize a low pass (“Butterworth”) filter to attenuate high frequency readings. This type of filter is a signal processing filter designed to have a frequency response as flat as possible in the passband, i.e., a maximally flat magnitude filter, and may be implemented in the software associated with the microcontroller 80.

[0029] The output from the filter is averaged using an exponential moving average algorithm. The resulting average from each of the three axes is the acceleration measurement used to select the minimum acceleration within a range of speeds. The microcontroller 80 then sends the determined speed (having the minimum acceleration) to the motor controller 70, which in turns commands the motor 30 to operate the fan 10 at the determined speed.

[0030] Turning to FIG. 3, a possible flow of the automatic balance control is illustrated. In this example, when the fan 10 is inputted or commanded to change speed to a user-desired or commanded speed by any means except the controller, i.e., either manually by a user or automatically based upon a pre-determined setting, the fan 10 such as via the controller 70 (or microcontroller 80) calculates or determines a plurality of fan speeds corresponding to the commanded speed. For example, the calculation may be to determine of three (3) speeds, one just below the inputted or commanded speed (SC-1), the inputted or commanded speed (SC), and one just above the inputted or commanded speed (SC+1).

[0031] The automated balancing process then involves analyzing the acceleration data at the inputted speed (SC) as well as two nearby speeds (one below and one above the inputted speed (SC)) to determine whether the nearby speeds have less wobble than the inputted speed (SC). The actual or determined speed of the fan is then selected as the speed having the lowest acceleration measured of the three speeds (SC, SC-1, SC+1).

[0032] The actual fan speed (Sactual) is then checked periodically at defined intervals to ascertain whether the actual speed (Sactual) is within a predefined range of the commanded speed (SC). The predefined range may be defined as a range starting at half the distance from the lowest calculated speed (SCmin) to the commanded speed (SC) and ending at half the distance between the commanded speed (SC) and the uppermost calculated speed (SCmax). Once the actual fan speed (Sactual) is within the predefined range of the commanded speed (SC), a timer is started for a certain time to ensure steady state operation, such as forty (40) seconds.

[0033] At the expiration of the predefined time, another acceleration measurement is taken by the accelerometer 60 and saved as the acceleration value for that speed. The motor 30 is commanded by the controller 70 to operate the fan 10 at the lowest speed of the three previously calculated speeds. The process of checking the acceleration for this speed and the highest calculated speed is then repeated. The speed with the lowest acceleration or oscillation is chosen and saved.

[0034] If the fan 10 is inputted or commanded to the original speed again by a user, which would result in undesirable wobbling, the fan speed is automatically adjusted to the saved speed for that inputted or commanded speed. In other words, the inputted speed (determined to have an impermissible wobble) is automatically bypassed such that the fan operates at a nearby speed having a more desirable operating condition in terms of balance.

[0035] In another embodiment, the process involves analyzing the acceleration data collected by the accelerometer within a range of speeds. For example, if a user selects a speed that is 50% of the maximum speed of the fan, the process determines the minimum acceleration or oscillation between a range, such as 45% and 55%, of the maximum speed of the fan.  In other words, the process finds the minimum acceleration or oscillation within this particular range of speeds.  Based upon the acceleration detected by the accelerometer at each of the speeds, the controller 70 automatically selects the fan speed with the minimum acceleration within the range of speeds to minimize wobble.

[0036] Advantageously, the fan 10 with automated balance control is adaptable to unique installations and increases customer satisfaction. Wobbling may be automatically reduced or eliminated in real time without the need for intervention by the user or a maintenance technician. Such automated balance control increases the life of the fan 10 by protecting it from damage to itself or nearby structures.

[0037] As used herein, the following terms have the following meanings:

[0038] “A”, “an”, and “the” as used herein refers to both singular and plural referents unless the context clearly dictates otherwise. By way of example, “a compartment” refers to one or more than one compartment.

[0039] “About,”“substantially,”“generally” or “approximately,” as used herein referring to a measurable value, such as a parameter, an amount, a temporal duration, and the like, is meant to encompass variations of + / - 20% or less, preferably + / -10% or less, more preferably + / -5% or less, even more preferably + / -1% or less, and still more preferably + / -0.1% or less of and from the specified value, in so far such variations are appropriate to perform in the disclosed invention. However, it is to be understood that the value to which the modifier “about” refers is itself also specifically disclosed.

[0040] “Comprise”, “comprising”, “comprises” and “comprised of” as used herein are synonymous with “include”, “including”, “includes” or “contain”, “containing”, “contains” and are inclusive or open-ended terms that specifies the presence of what follows, e.g., such does not exclude or preclude the presence of additional, non-recited components, features, element, members, steps, known in the art or disclosed therein.

[0041] While certain embodiments have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. For example, while overhead fans of the type shown tend to be more susceptible to oscillation, the disclosed techniques may be applied to any type of fan, without limitation, including for instance pedestal fans, ventilating fans, directional fans, or the like. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the protection under the applicable law and that methods and structures within the scope of these claims and their equivalents be covered thereby.

Examples

Embodiment Construction

[0017] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and like numerals represent like details in the various figures. Also, it is to be understood that other embodiments may be utilized, and that process or other changes may be made without departing from the scope of the disclosure. The following detailed description is not to be taken in a limiting sense, and the scope of the invention is defined only by the appended claims and their equivalents.

[0018]As shown in FIG. 1, a representative fan, such as an overhead ceiling fan 10 is illustrated. The fan 10 is coupled with the ceiling C and suspended over the floor F. The fan 10 includes a support 20, which may be adapted to be directly coupled...

Claims

1. A fan adapted to operate at a plurality of speeds selectable by a user during operation of the fan, comprising:a motor;a rotatable hub coupled to the motor;a plurality of fan blades coupled to the rotatable hub;a sensor configured to sense acceleration values associated with the fan at the plurality of fan speeds; anda controller configured to, in response to a desired fan speed selected by the user during operation of the fan, dynamically initiating an automated balance control routine executed during operation of the fan and in real time, the automated balance control routine comprising: determining a plurality of fan speeds within a range including the desired fan speed, at least one fan speed lower than the desired fan speed and at least one fan speed higher than the desired fan speed; commanding the motor to operate the fan at each of the plurality of fan speeds; controlling the sensor to obtain acceleration values associated with the fan at each of the plurality of fan speeds; comparing the acceleration values; and automatically selecting, as an operating speed for continued operation, one of the plurality of fan speeds having a minimum acceleration value, and operating the fan at the selected operating speed instead of the desired fan speed, wherein the controller is further configured to store the selected operating speed as a replacement for the desired fan speed and, upon a subsequent input of the desired fan speed by the user, automatically operate the fan at the stored replacement speed.

2. The fan of claim 1, wherein the fan includes a support adapted to be connected to a ceiling.

3. The fan of claim 1, wherein the sensor comprises an accelerometer.

4. The fan of claim 3, wherein the accelerometer comprises a three-axis, capacitance-based accelerometer.

5. The fan of claim 3, wherein the accelerometer is configured to sense acceleration on three axes.

6. The fan of claim 1, wherein the sensor senses the acceleration values at a predefined interval.

7. The fan of claim 1, further including a user input to input the desired fan speed to the controller.

8. The fan of claim 1, wherein the controller monitors an actual fan operating speed to be within a predefined range of the desired fan speed.

9. A method of operating a fan during operation of the fan to dynamically minimize oscillation in real time within a range of fan speeds including a desired fan speed inputted by a user, comprising:in response to the fan being commanded to change speed to the desired fan speed, calculating a first fan speed less than the desired speed and a second fan speed greater than the desired fan speed, and measuring an acceleration value at the desired fan speed, the first fan speed less than the desired speed, and the second fan speed greater than the desired fan speed;selecting one of the desired fan speed, first fan speed and second fan speed having the lowest acceleration value as a selected fan speed; andoperating the fan at the selected fan speed, wherein operating the fan at the selected fan speed comprises automatically bypassing the desired fan speed when the selected fan speed differs from the desired fan speed;storing the selected fan speed as a replacement for the desired fan speed; andupon the desired fan speed being subsequently inputted by the user, automatically operating the fan at the stored selected fan speed.

10. The method of claim 9, further including monitoring the selected fan speed so as to be within a predefined range.

11. The method of claim 10, further including starting a timer for a certain time to ensure steady state operation once an actual fan speed is within the predefined range of the desired fan speed.

12. The method of claim 9, wherein the first fan speed is a fan speed just below the desired speed and the second fan speed is just above the desired speed.

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