A control device and control method for a fan speed of a range hood

Abstract

The application discloses a kind of control device and control method of range hood fan speed, multiple first magnetic parts are evenly distributed on the impeller of fan along the circumference, and multiple second magnetic parts are evenly distributed on the volute along the circumference;The number of the multiple first magnetic parts and second magnetic parts corresponds, and the lower of one of the second magnetic parts is provided with a pressure sensor.Judge whether the speed of impeller fluctuates;If the speed of impeller fluctuates, judge the speed of impeller is too fast or too slow, adjust the force according to the speed of impeller is too fast or too slow, until the speed of impeller is stable.The control device and control method of fan speed of the application can measure whether the speed fluctuates, and also can adjust the fluctuation of speed, using a set of device can realize measurement and adjustment at the same time, and the adjustment logic is simple, through the size of suction force or repulsive force in each predetermined interval adjustment, to get stable speed.Cost is low, adjustment efficiency is high, easy to realize industrialization.

Description

Technical Field

[0001] This invention relates to a control device and control method for a range hood, and particularly to a control device and control method for the fan speed of a range hood. Background Technology

[0002] Most range hoods on the market currently use AC motors. While these range hoods are simple in structure and low in cost, they employ a relatively simplistic method to control the fan system: simply powering on the motor to maintain a stable speed. There is no special control over this operating condition; when the conditions at the air inlet and outlet remain unchanged, the motor's operating state will not change. Furthermore, if the noise or smoke concentration is high, the range hood will not respond. Therefore, its operating mode is relatively simple and cannot achieve adjustments under more complex conditions, resulting in a less user-friendly experience.

[0003] Existing technologies also include adjusting fan speed based on the concentration of cooking fumes. For example, Chinese invention patent CN110030595A, "An Oil Fume Detection Device, Range Hood and Control Method," discloses a solution that controls fan speed based on oil fume concentration. However, this method directly adjusts fan parameters to change the fan speed, but range hoods typically have fixed fan speed settings, making adjustment impossible when oil fume concentration changes only slightly. Furthermore, even when the user manually sets a fixed speed, it's impossible to adjust the fan speed according to changes in oil fume concentration.

[0004] The operating logic of current household range hoods is that, given a fixed current value, the motor runs at a certain speed. However, due to changes in the internal flow field of the volute and other factors, the impeller speed will fluctuate within a certain range. Currently, there is no effective method to adjust the speed fluctuation at a fixed speed setting. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defect of the prior art that cannot adjust the impeller speed of the range hood in real time, and to provide a control device and control method for the speed of the range hood fan.

[0006] This invention solves the above-mentioned technical problems through the following technical solution: a control device for the fan speed of a range hood, characterized in that it includes,

[0007] Multiple first magnetic components are evenly distributed circumferentially on the impeller of the wind turbine, and multiple second magnetic components are evenly distributed circumferentially on the volute.

[0008] The number of the plurality of first magnetic elements and second magnetic elements corresponds, and a pressure sensor is provided below one of the second magnetic elements;

[0009] When the motor drives the impeller to rotate, the repulsive or attractive forces generated between the first and second magnetic components cause fluctuations in the pressure sensor data.

[0010] Preferably, the first magnetic element and the second magnetic element are magnets, electromagnets, or coils, and the magnitude of the force exerted by the second magnetic element and / or the first magnetic element is adjustable.

[0011] A method for controlling the speed of a range hood fan, applied to the aforementioned range hood fan speed control device, is characterized by comprising the following steps:

[0012] Determine whether the impeller speed fluctuates; if the impeller speed fluctuates, determine whether the impeller speed is too fast or too slow, and adjust the force according to whether the impeller speed is too fast or too slow until the impeller speed stabilizes. The force is the attraction or repulsion between multiple first magnetic components and second magnetic components.

[0013] Preferably, determining whether the impeller speed fluctuates specifically includes: acquiring the real-time speed of the impeller; and obtaining the average speed n over a preset time period based on the real-time speed of the impeller. v If, within a preset time period, the number of times the difference between the real-time rotational speed and the average rotational speed exceeds the first preset threshold is greater than a preset number, then the impeller rotational speed will fluctuate.

[0014] Preferably, obtaining the real-time rotational speed of the impeller specifically involves obtaining the extreme value F of the pressure sensor within a preset time period. m Multiple time points t1, t2, t3...t N The real-time rotational speed of the impeller is obtained according to the following formula:

[0015]

[0016] In the formula, n i Let be the real-time rotational speed at time i, m be the number of the first magnetic components, and t be the rotational speed at time i. i+1 and t i These are the extreme moments of the (i+1)th and i-th pressure values.

[0017] Preferably, before determining whether the impeller speed is too fast or too slow, the method further includes determining whether the motor is in gear adjustment mode; if so, the method returns to continue determining whether the impeller speed fluctuates.

[0018] Preferably, the determination of whether the impeller speed is too fast or too slow specifically involves:

[0019] Obtain the comparison pressure value F from the pressure sensor. i The difference between the comparative pressure value and the expected pressure value, and the trend of the difference;

[0020] If the difference is greater than or equal to the second preset threshold, and the trend of the difference is decreasing, then the rotation speed is determined to be too slow.

[0021] If the difference is greater than or equal to the second preset threshold, and the trend of the difference is increasing, then the rotation speed is determined to be too fast.

[0022] The comparison pressure value F i The expected pressure value is the pressure value after a predetermined interval from any extreme pressure value, where the expected pressure value is the extreme value F of the pressure sensor. m The predetermined interval Δt is the time / m taken for the impeller to actually rotate one revolution, where m is the number of the first magnetic components.

[0023] Preferably, the force is adjusted according to whether the impeller speed is too fast or too slow, specifically,

[0024] If the rotational speed is determined to be too slow or too fast, then starting from the moment when any pressure value reaches its extreme value, the force is activated for a first predetermined period and deactivated for a second predetermined period; and the force is increased, decreased, or maintained according to its type; or...

[0025] If it is determined that the rotation speed is too slow or too fast, the force is activated within a first predetermined period starting from the moment when any pressure value is at its extreme value, and the force is activated in the opposite direction within a second predetermined period, and the force is increased, decreased or maintained according to the type of the force.

[0026] Preferably, both the first predetermined period and the second predetermined period are within a predetermined interval, where the predetermined interval Δt is the time / m taken for the impeller to actually rotate one revolution, and m is the number of the first magnetic components.

[0027] Preferably, the impeller rotation speed is stable, specifically, the difference between the comparison pressure value and the expected pressure value is less than the second preset threshold.

[0028] Preferably, after adjusting the magnitude of the force according to whether the impeller rotation speed is too fast or too slow, if the difference between the comparative pressure value and the expected pressure value is still greater than or equal to the second preset threshold and has an increasing trend, then the force is adjusted to the opposite magnitude trend.

[0029] Preferably, if the applied force exceeds a preset range, the magnitude of the applied force is maintained, and it is determined whether the impeller speed is stable. If the speed is still unstable at this time, a prompt indicating debugging failure is returned.

[0030] The significant advantages of this invention are as follows: The fan speed control device and method of this invention can measure whether the speed fluctuates through the first and second magnetic components, and can also adjust the speed fluctuation using the same first and second magnetic components. It is not only simple in structure, but also allows for measurement and adjustment using a single device. Furthermore, the adjustment logic is simple; a stable speed is obtained by adjusting the magnitude of the attraction or repulsion force within predetermined intervals. It is low in cost, highly efficient in adjustment, and easy to industrialize. The device and method of this invention only require slight modifications to existing range hoods and the addition of a few components, and can be directly applied regardless of whether the range hood uses an AC or DC motor, thus broadening its application range. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the fan structure of the range hood disclosed in Embodiment 1 of the present invention;

[0032] Figure 2 This is a cross-sectional view of the fan structure of the range hood disclosed in Embodiment 1 of the present invention;

[0033] Figure 3 This is a flowchart illustrating the method for controlling the fan speed of a range hood according to Embodiment 2 of the present invention.

[0034] Figure 4 This is a flowchart illustrating step S3 of the method for controlling the fan speed of a range hood disclosed in Embodiment 2 of the present invention. Detailed Implementation

[0035] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0036] Example 1

[0037] like Figure 1 , 2 The diagram shows the fan structure of a range hood disclosed in Embodiment 1 of the present invention. The fan mechanism of the range hood includes a fan 10, which includes a volute 11, an impeller 12, and a motor 13 located within the volute 11. The motor 13 is located at the center of the impeller 12 and is fixedly connected to the volute 11 via a motor bracket 14. The impeller 12 is connected to the output shaft of the motor 13 via an impeller bracket 15. The motor 13 drives the impeller 12 and the impeller bracket 15 to rotate.

[0038] On the surface of the impeller 12 facing the volute 11, a plurality of first magnetic elements 2 are evenly distributed along its edge. Preferably, on the volute 11, around the air outlet of the volute 11, a plurality of second magnetic elements 3 are evenly distributed circumferentially. The positions of the first magnetic elements 2 and the second magnetic elements 3 are corresponding, and their quantities are also one-to-one.

[0039] The magnetism and magnitude of the first magnetic element 2 and / or the second magnetic element 3 are adjustable, and a pressure sensor 4 is disposed below one of the second magnetic elements 3. When the impeller 12 rotates under the drive of the motor 13, the first magnetic element 2 corresponds to the second magnetic element 3. When the impeller rotates, each first magnetic element 2 passes the second magnetic element 3 corresponding to the pressure sensor 4, and the pressure sensor 4 will generate a corresponding pressure value change due to the attraction or repulsion between the first magnetic element 2 and the second magnetic element 3. For example, if there is an attraction between the first magnetic element 2 and the second magnetic element 3, the pressure of the pressure sensor 4 is minimal when the first magnetic element 2 and the second magnetic element 3 are perfectly aligned. During rotation, multiple first magnetic elements 2 pass the pressure sensor 4 one by one, and the pressure value of the pressure sensor 4 decreases and then increases as the first magnetic element 2 moves closer and further away. When there is a repulsive force between the first magnetic element 2 and the second magnetic element 3, the pressure value of the pressure sensor 4 is the maximum when the first magnetic element 2 and the second magnetic element 3 are completely aligned. During the rotation, multiple first magnetic elements 2 pass by the pressure sensor 4 one by one. The pressure value of the pressure sensor 4 increases and then decreases as the first magnetic elements 2 move closer and further away.

[0040] Preferably, the magnetic strength of the first magnetic element 2 and / or the second magnetic element 3 can be adjusted. For example, it can be in the form of a coil, with its magnetic strength controlled by the magnitude of the current, or it can be an electromagnet, with its magnetic strength controlled by the magnitude of the current, thereby adjusting the magnitude of the force between the first and second magnetic elements. Furthermore, there must be a switch between the first and second magnetic elements; that is, in the closed state, there is no force between them, and in the open state, they generate attraction or pull through magnetism. This switch can be a magnetic switch on the first magnetic element, a switch on the second magnetic element, or a switch on both. Preferably, the magnetic poles of the first magnetic element 2 are also adjustable, thereby adjusting the attraction or repulsion between the first and second magnetic elements.

[0041] The first magnetic component can be a magnet, a coil, or an electromagnet, and the second magnetic component can also be a magnet, a coil, or an electromagnet. The first and second magnetic components must be evenly arranged circumferentially to ensure dynamic balance during rotation. Furthermore, when the force between the first and second magnetic components is adjusted—that is, when the magnetism of the second and / or first magnetic components is adjusted—all the second and / or first magnetic components are adjusted together to maintain dynamic balance. Preferably, the first magnetic component 2 is a magnet, as its location on the impeller makes it inconvenient to connect to a circuit for control. The second magnetic component 3 is an electromagnet, whose magnetic strength can be adjusted by controlling its current, thereby allowing the interaction force between the first and second magnetic components 2 and 3 to be adjusted.

[0042] Therefore, by calculating the time interval between the extreme values ​​of this pressure, the impeller speed can be determined, and whether the speed fluctuates. After determining that the speed fluctuates, a certain force can be applied during the impeller rotation by adjusting the magnitude of the attraction or repulsion between the first and second magnetic components to stabilize the impeller speed, thereby achieving the effect of regulating the fan speed.

[0043] Example 2

[0044] like Figure 3 The diagram shown is a flowchart of the fan speed control method according to Embodiment 2 of the present invention. Specifically,

[0045] S1, during the process of the motor driving the impeller to rotate, the switch between the first and second magnetic components is opened. This switch can be located on the first magnetic component, the second magnetic component, or both. Once the switch is opened, a repulsive or attractive force is generated between the first and second magnetic components. Therefore, by judging and adjusting this force, the impeller speed can be adjusted. Adjusting this force is achieved simply by adjusting the magnitude and direction of the magnetic force between the first and second magnetic components. Preferably, when the second magnetic component is a coil or electromagnet, adjusting the current to the second magnetic component controls its magnetic force, and thus the magnitude of the force between the first and second magnetic components can also be achieved by adjusting the current.

[0046] S2, determine whether the impeller speed fluctuates;

[0047] Specifically, the real-time rotational speed of the impeller is obtained; and the average rotational speed n over a preset time period is obtained based on the real-time rotational speed of the impeller. v If the number of times the difference between the real-time rotation speed and the average rotation speed exceeds the first preset threshold within a preset time period is greater than a preset number, then the rotation speed of the impeller fluctuates.

[0048] The specific steps for obtaining the real-time rotational speed of the impeller are as follows: Obtain the extreme value F of the pressure sensor within a preset time period. m Multiple time points t1, t2, t3...t N These multiple moments are the moments when the first and second magnetic components are aligned, at which point the pressure sensor experiences its extreme value F. m The extreme value F mThe value can be either a maximum or a minimum. If the force between the first and second magnetic components is attractive, the extreme value is the minimum; if the force is repulsive, the extreme value is the maximum. The preset time period can be set as needed, typically 5-10 seconds. By measuring the pressure value of the pressure sensor through the interaction of the forces between the first and second magnetic components, the rotational speed within the preset time period can be obtained, thus determining whether the rotational speed fluctuates.

[0049] The real-time rotational speed of the impeller is obtained according to the following formula:

[0050] The unit is revolutions per second.

[0051] In the formula, n i Let be the real-time rotational speed at time i, m be the number of the first magnetic components, and t be the rotational speed at time i. i+1 and t i These represent the (i+1)th and ith pressure extreme values. Since the impeller has m uniformly arranged first magnetic components along its perimeter, the pressure sensor will obtain m extreme pressure values ​​after one revolution of the impeller. Here, m is a natural number greater than or equal to 2.

[0052] Once the real-time rotational speed is obtained, the average rotational speed can be calculated.

[0053] n v =(∑n i ) / N-1, i=1,2,3,……,N-1; the unit is revolutions per second.

[0054] Real-time rotational speed n within a preset time period i With average rotational speed n V The difference Δn between i If the number of times the first preset threshold is exceeded is k, then the impeller speed is considered to be fluctuating. If the impeller speed does not fluctuate, the program exits; if the impeller speed fluctuates, the following steps continue.

[0055] The first preset threshold is b×n v b is a coefficient with a range of (0, 0.02).

[0056] The number of times k exceeds the first preset threshold is determined by the impeller speed, for example, if the average impeller speed is n. v If the preset time period is T, then the number of times k = a × m × T / n v Here, 'a' is a coefficient, such as 0.1 or 0.2, etc., and 'm' is the number of the first magnetic components. T / n v The total number of impeller revolutions within a preset time period is m×T / n v This refers to the total number of real-time rotational speeds measured within a preset time period. When the real-time rotational speed ni With average rotational speed n v The difference Δn between i If the number of times exceeds the first preset threshold is too many, it indicates that the rotational speed is fluctuating; otherwise, it indicates that the rotational speed is stable.

[0057] S3, if the impeller speed fluctuates, determine whether the impeller speed is too fast or too slow.

[0058] Before proceeding to this step, it is necessary to determine whether the motor is in a gear-shifting position. If it is in a gear-shifting position, for example, if the user increases or decreases the impeller speed by operating the button, it is necessary to return to step S2 and re-determine whether the speed fluctuates. If it is not in a gear-shifting position, continue with the following steps.

[0059] like Figure 4 As shown, when the speed fluctuates, it is necessary to determine whether the impeller speed is too fast or too slow. The specific steps are as follows:

[0060] S31, Obtain the comparison pressure value F from the pressure sensor. i The difference between the comparative pressure value and the expected pressure value, and the trend of the difference;

[0061] S32, if the difference between the compared pressure value and the expected pressure value is greater than or equal to the second preset threshold, and the trend of the difference is decreasing, then it is determined that the rotation speed is too slow;

[0062] S33, if the difference between the initial value of the comparison pressure and the expected pressure value is greater than or equal to the second preset threshold, and the trend of the difference is increasing, then it is determined that the rotation speed is too fast;

[0063] Wherein, the comparison pressure value F i The expected pressure value is the pressure value after a predetermined interval Δt following any extreme pressure value, where the expected pressure value is the extreme value F of the pressure sensor. m The predetermined interval Δt is the time / m taken for the impeller to actually rotate one revolution, where m is the number of the first magnetic components. The second preset threshold is typically F. k =c×|F m -G|, where c is a coefficient ranging from (0, 0.5), and G is the weight of the second magnetic component.

[0064] Specifically, the comparison pressure value Fi is the pressure value after a predetermined interval from any extreme pressure value. Any extreme pressure value occurs when the first and second magnetic components are aligned and the force between them is at its maximum. The predetermined interval is the time taken for the impeller to rotate one revolution divided by m, where m is the number of the first magnetic components. Therefore, the predetermined interval Δt is the time difference between any extreme pressure value and the next extreme pressure value. If the rotational speed is stable, after the impeller rotates from any extreme pressure value to the next extreme pressure value (i.e., after the predetermined interval), the first and second magnetic components should also be aligned at the next extreme pressure value. Therefore, the comparison pressure value F at this time... i It should be the expected pressure value, i.e., the comparison pressure value F. i The extreme value F of the pressure sensor m If there is no significant difference, but the difference is large, exceeding the second preset threshold, it indicates that the first and second magnetic components are not aligned after a predetermined interval Δt. Therefore, it is necessary to determine the comparison pressure value F. i If the trend of the difference is decreasing, it indicates that the first magnetic component is approaching the second magnetic component, i.e., the rotation speed is too slow; if the trend of the difference is increasing, it indicates that the first magnetic component is moving away from the second magnetic component, i.e., the rotation speed is too fast.

[0065] Among them, the extreme value F of this pressure value m The average of multiple pressure values ​​can be obtained before determining whether the rotational speed is too fast or too slow. This measurement step can be performed separately or simultaneously by obtaining the average of multiple pressure values ​​when determining whether the rotational speed fluctuates in step S2.

[0066] S4 adjusts the force according to whether the impeller speed is too fast or too slow until the impeller speed stabilizes.

[0067] The force referred to is the attraction or repulsion force between the plurality of first magnetic components and second magnetic components.

[0068] If the difference between the compared pressure value and the expected pressure value is less than the second preset threshold, it means that even if the impeller speed fluctuates, no adjustment is needed, and the process returns to continue judging whether the impeller speed fluctuates.

[0069] If it is determined that the rotation speed is too fast or too slow, the force is activated within a first predetermined period T1 and deactivated within a second predetermined period T2, starting from the moment when any pressure value is at its extreme value; and the force is increased or decreased according to the type of the force, or the magnitude of the force is kept constant.

[0070] The first predetermined period T1 and the second predetermined period T2 are both located within the predetermined interval Δt, where the predetermined interval Δt is the time / m taken for the impeller to actually rotate one revolution, and m is the number of the first magnetic components.

[0071] The first predetermined period T1 and the second predetermined period T2 are both located within the predetermined interval Δt. For example, the first predetermined period T1 is the first half of the predetermined interval Δt, and the second predetermined period T2 is the last half of the predetermined interval Δt; or the first predetermined period T1 is the last half of the predetermined interval Δt, and the second predetermined period T2 is the first half of the predetermined interval Δt; or the second predetermined period T2 is the first three-quarters of the predetermined interval Δt, and the first predetermined period T1 is one-quarter of the predetermined interval Δt; or the first predetermined period T1 is the first one-quarter of the predetermined interval, and the second predetermined period T2 is the last one-quarter of the predetermined interval. That is, the length and order of the first and second predetermined periods can be set as needed within each predetermined interval Δt.

[0072] The following example uses the first predetermined period T1 as the second half of the predetermined interval Δt and the second predetermined period T2 as the first half of the predetermined interval Δt.

[0073] If it is determined that the rotational speed is too slow or too fast, then starting from the moment when any pressure value is at its extreme value, the force is turned off at 1 / 2 predetermined intervals and turned on at 1 / 2 predetermined intervals, and the force is reduced or increased according to the type of force.

[0074] By first closing the force at a predetermined interval of 1 / 2 from any extreme pressure value (i.e., the force between the first and second magnetic components disappears, the first magnetic component moves away from the second, and the impeller rotates freely), and then opening the force at the next predetermined interval (i.e., when the first magnetic component begins to approach the second), the force is adjusted according to whether the rotational speed is too fast or too slow. This adjustment is made only in the latter half of the predetermined interval to prevent the forces from canceling each other out. As the first magnetic component moves closer to and away from the second magnetic component with the impeller's rotation, the same force has opposite effects on the speed changes between them. For example, as the first magnetic component approaches the second, the attraction increases the rotational speed, while as it moves away, the attraction decreases it. Therefore, adjusting only in the first or second half of the predetermined interval is sufficient to regulate the rotational speed.

[0075] Of course, the opening of the first half or the second half of the predetermined interval can be adjusted as needed. The following example uses the first predetermined cycle as the second half of the predetermined interval and the second predetermined cycle as the first half of the predetermined interval, that is, the first half of the predetermined interval is closed and the second half is open.

[0076] If the rotation speed is too high and the force is attractive, the force between the two needs to be reduced in the first predetermined cycle. If the force is repulsive, the force between the two needs to be increased or kept constant in the first predetermined cycle. Both decreasing and increasing the force can be done by adjusting the current to the electromagnet.

[0077] If the rotation speed is too slow and the force is attractive, the force between the two will be increased or kept constant during the first predetermined cycle. If the force is repulsive, the force between the two will be decreased during the first predetermined cycle. Both increasing and decreasing the force can be achieved by adjusting the current to the electromagnet.

[0078] For example, consider the opening force during the first half of a predetermined interval. That is, the first predetermined period is the first 1 / 2 of the predetermined interval, and the second predetermined period is the second 1 / 2 of the predetermined interval.

[0079] If the rotation speed is too high and the force is attractive, then in the first predetermined cycle, the force between the two needs to be increased or kept constant. Conversely, if the force is repulsive, then the force between the two needs to be decreased in the first predetermined cycle. Both increasing and decreasing the force can be achieved by adjusting the current to the electromagnet.

[0080] If the rotation speed is too fast or too slow, and the force is attractive, then the force between the two is reduced in the first predetermined cycle. If the force is repulsive, then the force between the two is increased or kept constant in the first predetermined cycle. Both decreasing and increasing the force can be achieved by adjusting the current to the electromagnet.

[0081] The impeller rotation speed is stable, specifically, the difference between the compared pressure value and the expected pressure value is less than the second preset threshold. During the above adjustment process, the difference between the compared pressure value and the expected pressure value can continue to be monitored. The expected pressure value needs to be remeasured after multiple rotations because the force between the first and second magnetic components has changed, and the extreme value of the pressure value previously used to determine whether there is fluctuation should no longer conform to the current expected pressure value, so it should be remeasured. Alternatively, those skilled in the art can pre-determine the extreme value of the pressure based on experience, determining the magnitude of the force between the first and second magnetic components, and then storing and retrieving it from the system.

[0082] After adjusting the magnitude of the force according to whether the rotation speed is too fast or too slow and the type of force for a certain period of time, if the difference between the comparison pressure value and the expected pressure value is still greater than or equal to the second preset threshold, and the difference has an increasing trend, it indicates that the adjustment trend is wrong, and the force is adjusted in the opposite direction of the magnitude trend.

[0083] S5. During the adjustment process, if the applied force exceeds the preset range, for example, when the working current of the second magnetic component has exceeded its normal working current range, either too large or too small, then the current should not be adjusted further, that is, the magnitude of the applied force should be maintained, and the adjustment should be determined by judging whether the impeller speed is stable. If the speed is still unstable at this time, the prompt of adjustment failure will be returned. If the speed has stabilized, it means that the adjustment is successful.

[0084] As another implementation of this embodiment, if it is determined that the rotation speed is too slow or too fast, the force is activated within a first predetermined period T1 starting from the moment when any pressure value is at its extreme value, and the force is activated in the opposite direction within a second predetermined period T2. The force is increased or decreased or kept constant depending on the type of the force.

[0085] For example, if both the first and second predetermined periods are 1 / 2 predetermined intervals, then the force is activated at the 1 / 2 predetermined interval, and activated in the remaining 1 / 2 predetermined interval in the opposite direction, meaning the repulsive and attractive forces are reversed. This means the magnetic poles of the second magnetic component are set in opposite directions.

[0086] Specifically, for example, the first half of the predetermined interval is the second predetermined period, and the second half of the predetermined interval is the first predetermined period. That is, the first half of the predetermined interval is the reverse force, and the second half is the positive force.

[0087] If the rotation speed is too high, and the applied force is attractive, then in the first predetermined cycle, the attractive force is applied between the two forces, and in the second predetermined cycle, the opposing force (repulsive force) is applied, with the magnitude of the force decreasing. Conversely, if the applied force is repulsive, then in the first predetermined cycle, the attractive force is applied between the two forces, and in the second predetermined cycle, the opposing force (attractive force) is applied, with the magnitude of the force increasing or remaining constant. The force can be decreased or increased by adjusting the current to the electromagnet.

[0088] If the rotation speed is too fast or too slow, and the applied force is attractive, then attractive force is applied in the first predetermined cycle, and repulsive force is applied in the second predetermined cycle, increasing the force between the two or keeping it constant. Conversely, if the applied force is repulsive, then repulsive force is applied in the first predetermined cycle, attractive force is applied in the second predetermined cycle, and the force between the two is decreased. Decreasing or increasing the force can be achieved by adjusting the current to the electromagnet.

[0089] The fan speed control method of the present invention can measure whether the speed fluctuates using a first magnetic component and a second magnetic component. Furthermore, it can also adjust the speed fluctuation using the same first and second magnetic components. This method is not only simple in structure, but also allows for measurement and adjustment using a single device. Moreover, the adjustment logic is simple; a stable speed is obtained by adjusting the magnitude of the attraction or repulsion force within predetermined intervals. It is low in cost, highly efficient in adjustment, and easy to industrialize.

[0090] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A control method of a rotation speed of a range hood fan, which is applied to a control device of the rotation speed of the range hood fan, characterized by, The control device comprises: A plurality of first magnetic elements are evenly distributed on the impeller of the fan in the circumferential direction, and a plurality of second magnetic elements are evenly distributed on the volute in the circumferential direction; The number of the plurality of first magnetic elements and the plurality of second magnetic elements corresponds, and a pressure sensor is arranged below one of the second magnetic elements; When the motor drives the impeller to rotate, the repulsive or attractive force generated between the first magnetic elements and the second magnetic elements causes the data of the pressure sensor to fluctuate and change; The first magnetic elements and the second magnetic elements are magnets, electromagnets or coils, and the attractive or repulsive force of the second magnetic elements and / or the first magnetic elements is adjustable; The control method comprises the following steps: determining whether the rotational speed of the impeller fluctuates; if the rotational speed of the impeller fluctuates, determining whether the rotational speed of the impeller is too fast or too slow, adjusting the attractive or repulsive force between the plurality of first magnetic elements and the plurality of second magnetic elements according to whether the rotational speed of the impeller is too fast or too slow, and until the rotational speed of the impeller is stable; Before determining whether the rotational speed of the impeller is too fast or too slow, the method further comprises determining whether the motor is in gear shifting, and if so, returning to determine whether the rotational speed of the impeller fluctuates.

2. The method of claim 1, wherein the step of determining the speed of the fan of the range hood is performed by a microprocessor. The judging whether the rotating speed of the impeller fluctuates specifically comprises: obtaining a real-time rotating speed of the impeller; obtaining an average rotating speed n of the impeller in a preset time period according to the real-time rotating speed of the impeller v If the difference between the real-time rotating speed and the average rotating speed exceeds the first preset threshold value for more than the preset number of times in the preset time period, the rotating speed of the impeller fluctuates.

3. The method of claim 2, wherein the step of determining the speed of the fan of the range hood is performed by the controller. The real-time rotating speed of the impeller is obtained, specifically, the pressure value of the pressure sensor in a preset time period is obtained as an extreme value F m at multiple moments t1, t2, t3,..., t N The real-time rotating speed of the impeller is obtained according to the following formula: In the formula, n i is the real-time rotating speed at the i th moment, m is the number of the first magnetic members, t i+1 and t i are the i+1 th and i th pressure value extreme moments.

4. The method of claim 1, wherein the step of determining the speed of the fan of the range hood is performed by a microprocessor. The determination of whether the rotational speed of the impeller is too fast or too slow comprises: acquiring a comparative pressure value F of the pressure sensor i a difference between the comparative pressure value and an expected pressure value, and a trend of the difference if the difference is greater than or equal to the second preset threshold value and the change trend of the difference is decreasing, it is determined that the rotational speed is too slow; if the difference is greater than or equal to the second preset threshold value and the change trend of the difference is increasing, it is determined that the rotational speed is too fast; The comparison pressure value F i The expected pressure value is the pressure value of the pressure sensor at a predetermined interval Δt after the extreme value F of any pressure value m The predetermined interval Δt is the time consumed by the actual rotation of the impeller for one circle / m, and m is the number of the first magnetic members.

5. The method of claim 1 or 4, wherein the step of determining the fan speed of the range hood fan is performed by a microcomputer. Adjusting the attractive or repulsive force according to whether the rotational speed of the impeller is too fast or too slow comprises: if it is determined that the rotational speed is too slow or too fast, starting from any time point at which a pressure value is an extreme value, turning on the attractive or repulsive force in a first predetermined period, turning off the attractive or repulsive force in a second predetermined period, and increasing, decreasing or keeping the attractive or repulsive force according to the type of the attractive or repulsive force; or if it is determined that the rotational speed is too slow or too fast, starting from any time point at which a pressure value is an extreme value, turning on the attractive or repulsive force in a first predetermined period, turning on the attractive or repulsive force in reverse in a second predetermined period, and increasing, decreasing or keeping the attractive or repulsive force according to the type of the attractive or repulsive force.

6. The method of claim 5, wherein the step of determining the speed of the fan of the range hood is performed by the controller. The first predetermined period and the second predetermined period are both within a predetermined interval, and the predetermined interval Δt is the time consumed by the actual rotation of the impeller for one revolution / m, and m is the number of the first magnetic elements.

7. The method of claim 4, wherein the step of determining the speed of the fan of the range hood is performed by a microprocessor. The stability of the rotational speed of the impeller comprises that the difference between the comparison pressure value and the expected pressure value is less than the second preset threshold value.

8. The method of claim 4, wherein the step of determining the speed of the fan of the range hood is performed by a microprocessor. After adjusting the attractive or repulsive force according to whether the rotational speed of the impeller is too fast or too slow, if the difference between the comparison pressure value and the expected pressure value is still greater than or equal to the second preset threshold value and has a trend of increasing, the attractive or repulsive force is adjusted to the opposite trend.

9. The method of claim 4, wherein the step of determining the speed of the fan of the range hood is performed by a microprocessor. If the attractive or repulsive force exceeds a preset range, the size of the attractive or repulsive force is kept, and whether the rotational speed of the impeller is stable is determined; if the rotational speed is still unstable at this time, a prompt of debugging failure is returned.

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