Constant air volume control method and device of fan, air conditioning equipment and medium

Abstract

The invention discloses a constant air volume control method and device for a fan, air conditioning equipment and a medium, and the method comprises the steps that operation data of the fan in a preset delay time period are obtained, and the preset delay time period is obtained after constant air volume control is conducted on the fan according to a first constant air volume control strategy till a first stable condition is met; continuously operating the first constant air volume control strategy for a time period; if it is judged that constant air volume control over the fan does not meet the second stable condition according to the operation data, the change period of an air duct system where the fan is located is recognized; and a constant air volume control strategy for the fan is adjusted according to the change period, and constant air volume control is conducted on the fan according to the adjusted second constant air volume control strategy. According to the method and the device, the technical problem of unstable constant air volume control caused by periodic change of an air duct system in related technologies is solved.

Description

Technical Field

[0001] This invention belongs to the field of home appliance technology, and particularly relates to a constant air volume control method, device, air conditioning equipment and medium for a fan. Background Art

[0002] For ducted air conditioning equipment, if a long exhaust duct is required for air intake, the increased static pressure caused by the long duct will affect the actual air volume. At the same rotational speed, a short exhaust duct will produce a larger air volume at the outlet, while a long exhaust duct will produce a smaller air volume. However, the actual length of the exhaust duct installed by the user is entirely limited by the installation environment, resulting in poor consistency. Therefore, a constant air volume control mode is needed to achieve a constant air volume output at the equipment outlet under different duct lengths installed by the user.

[0003] When the duct system experiences stable fluctuations, such as when the user's air outlet is in swing mode, or when another fresh air system is operating within the duct causing periodic changes in the entire duct system, these periodic changes may not match the constant air volume control cycle, leading to unstable constant air volume control. Summary of the Invention

[0004] This invention provides a constant air volume control method, device, air conditioning equipment, and medium for a fan, to solve the technical problem of unstable constant air volume control caused by periodic changes in the duct system in related technologies.

[0005] In a first aspect of the present invention, a constant air volume control method for a fan is provided, comprising: acquiring operating data of the fan during a preset delay period, wherein the preset delay period is a period during which the first constant air volume control strategy is continued to operate after the fan is controlled with constant air volume according to a first constant air volume control strategy until a first stability condition is met; if it is determined from the operating data that the constant air volume control of the fan does not meet a second stability condition, identifying the change cycle of the air duct system in which the fan is located; adjusting the constant air volume control strategy for the fan according to the change cycle, and controlling the fan with constant air volume according to the adjusted second constant air volume control strategy.

[0006] In conjunction with the first aspect, in some embodiments, the first constant air volume control strategy is a control strategy that periodically adjusts the speed of the fan according to a first control cycle. The step of controlling the fan with constant air volume according to the adjusted second constant air volume control strategy includes: periodically adjusting the speed of the fan according to a second control cycle, wherein the second control cycle is different from the first control cycle and the second control cycle matches the change cycle.

[0007] In conjunction with the first aspect, in some embodiments, adjusting the constant air volume control strategy for the fan according to the change period includes: determining a second control period based on a preset proportional coefficient and the change period, wherein the second control period and the change period satisfy a linear relationship, and the second control period is greater than or equal to the change period; and adjusting the control period for constant air volume control of the fan from the first control period to the second control period.

[0008] In conjunction with the first aspect, in some embodiments, adjusting the constant air volume control strategy for the fan according to the change cycle includes: obtaining the actual rotational speed of the fan within the change cycle; using the actual rotational speed as the target rotational speed for constant air volume control of the fan; and performing constant air volume control of the fan according to the adjusted second constant air volume control strategy includes: performing constant air volume control of the fan according to the target rotational speed so that the actual rotational speed of the fan is maintained at the target rotational speed.

[0009] In conjunction with the first aspect, in some embodiments, obtaining the actual rotational speed of the fan within the change cycle includes: obtaining multiple rotational speed sampling values ​​of the fan within at least one change cycle; and calculating the average value based on the multiple rotational speed sampling values ​​to obtain the actual rotational speed.

[0010] In conjunction with the first aspect, in some embodiments, identifying the change period of the duct system where the fan is located includes: obtaining the time span between two adjacent crossings of the characteristic value fluctuation band of the fan characteristic parameters, wherein the characteristic value fluctuation band is established based on a curve model for the current target air volume, the curve model representing the mapping relationship between the fan speed and the fan characteristic parameters under the current target air volume, the curve model being used to obtain the target characteristic value of the fan characteristic parameters required for constant air volume control of the fan according to the first constant air volume control strategy; and determining the change period based on the time span.

[0011] In conjunction with the first aspect, in some embodiments, the characteristic value fluctuation band includes an upper-biased fluctuation band and a lower-biased fluctuation band of the target characteristic value. Determining the change period based on the time span includes: if the actual characteristic value of the wind turbine characteristic parameter changes from above the upper-biased fluctuation band to below the lower-biased fluctuation band, or changes from below the lower-biased fluctuation band to above the upper-biased fluctuation band, it indicates that the actual characteristic value of the wind turbine characteristic parameter has crossed the characteristic value fluctuation band; and twice the time span is taken as the change period.

[0012] In conjunction with the first aspect, in some embodiments, the characteristic value fluctuation band includes an upper-biased fluctuation band and a lower-biased fluctuation band of the target characteristic value. Determining the change period based on the time span includes: if the actual characteristic value of the wind turbine characteristic parameter changes sequentially from above the upper-biased fluctuation band to below the lower-biased fluctuation band and above the upper-biased fluctuation band, or changes sequentially from below the lower-biased fluctuation band to above the upper-biased fluctuation band and below the lower-biased fluctuation band, it indicates that the actual characteristic value of the wind turbine characteristic parameter crosses the characteristic value fluctuation band; and the time span is used as the change period.

[0013] In conjunction with the first aspect, in some embodiments, obtaining the time span of the actual characteristic value of the wind turbine characteristic parameter across two adjacent characteristic value fluctuation bands includes: recording a first moment when the actual characteristic value of the wind turbine characteristic parameter crosses the characteristic value fluctuation band for the first time after the preset delay period; recording a second moment when the actual characteristic value of the wind turbine characteristic parameter crosses the characteristic fluctuation band for the second time after the preset delay period; and determining the time span based on the time difference between the second moment and the first moment.

[0014] In conjunction with the first aspect, in some embodiments, the operating data within the preset delay period includes the actual feature values ​​of the fan feature parameters sampled within the preset delay period; before identifying the change cycle of the duct system where the fan is located, the method further includes: obtaining the number of times the actual feature values ​​of the fan feature parameters cross the feature value fluctuation band within the preset delay period; if the number reaches a preset number threshold, it indicates that the constant air volume control of the fan according to the first constant air volume control strategy does not meet the second stability condition.

[0015] In conjunction with the first aspect, in some embodiments, before acquiring the operating data of the fan within a preset delay period, the method further includes: during the process of performing constant airflow control on the fan according to the first constant airflow control strategy, for each acquired target feature value and actual feature value, determining the upper and lower bias thresholds on the feature value fluctuation band for the current acquisition based on the target feature value acquired in the current acquisition and the preset fluctuation bandwidth; comparing the actual feature value acquired in the current acquisition with the upper and lower bias thresholds on the feature value fluctuation band for the current acquisition; if the actual feature value acquired in the current acquisition does not exceed the upper and lower bias thresholds on the feature value fluctuation band for the current acquisition, it indicates that the constant airflow control of the fan according to the first constant airflow control strategy satisfies the first stability condition.

[0016] In a second aspect of the invention, a constant airflow control device for a fan is also provided, comprising: a data acquisition unit, configured to acquire operating data of the fan within a preset delay period, wherein the preset delay period is the period during which the first constant airflow control strategy continues to operate after the fan is controlled with constant airflow according to a first constant airflow control strategy until a first stability condition is met; a period identification unit, configured to identify the change period of the air duct system where the fan is located if it is determined from the operating data that the constant airflow control of the fan does not meet a second stability condition; a strategy adjustment unit, configured to adjust the constant airflow control strategy for the fan according to the change period; and a control execution unit, configured to perform constant airflow control on the fan according to the adjusted second constant airflow control strategy.

[0017] In a third aspect of the invention, an air conditioning device is provided, having a fan, the air conditioning device further comprising: a processor; and a memory for storing executable instructions of the processor, wherein the processor is configured to execute the instructions to implement the constant airflow control method of the fan described above.

[0018] In a fourth aspect of the invention, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the constant airflow control method for the fan described above.

[0019] According to one or more technical solutions provided in the embodiments of the present invention, at least the following technical effects or advantages are achieved:

[0020] This invention acquires the operating data of a fan within a preset delay period. The preset delay period is the time during which the fan is controlled with a constant air volume according to a first constant air volume control strategy until a first stability condition is met, and then the first constant air volume control strategy continues to operate. If the operating data indicates that the constant air volume control of the fan does not meet a second stability condition, the change cycle of the air duct system where the fan is located is identified. The constant air volume control strategy for the fan is adjusted according to the change cycle, and the fan is controlled with a constant air volume according to the adjusted second constant air volume control strategy. Because the operating data within the preset delay period does not meet the second stability condition, indicating that the change cycle of the duct system where the fan is located does not match the control cycle of the fan under the first constant air volume control strategy, continuing to use the first constant air volume control strategy to control the fan under constant air volume in this case will cause fluctuations in the constant air volume control. Therefore, the first constant air volume control strategy is not applicable. By identifying the change cycle of the duct system and adjusting the constant air volume control strategy for the fan according to the identified change cycle, the fan can be controlled under the adjusted second constant air volume control strategy, which can avoid fluctuations in the constant air volume control and thus improve the stability of the constant air volume control of the fan. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A flowchart of a constant air volume control method for a fan provided in some embodiments of the present invention is shown;

[0023] Figure 2 A schematic diagram of the eigenvalue fluctuation band is shown in some embodiments of the present invention;

[0024] Figure 3 A schematic diagram showing the actual feature value crossing the feature value fluctuation band in some embodiments of the present invention is shown;

[0025] Figure 4 A schematic diagram showing the actual feature value crossing the feature value fluctuation band in some other embodiments of the present invention is shown;

[0026] Figure 5 This invention illustrates a time-sharing diagram for calculating the actual rotational speed within a variation period in some other embodiments.

[0027] Figure 6 The diagram shows a schematic of the structure of a constant air volume control device for a fan provided in some embodiments of the present invention;

[0028] Figure 7 A schematic diagram of the structure of an air conditioning device provided in some embodiments of the present invention is shown. Detailed Implementation

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0030] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0031] This invention provides a constant airflow control method for a fan, which can be applied to air conditioning equipment with a fan to achieve a constant airflow output from the air outlet of the air conditioning equipment, such as an air purifier, air conditioner, heater, or fresh air system. Figure 1 As shown, the constant air volume control method for a fan provided by the present invention includes the following steps S101 to S103.

[0032] S101: Obtain the operating data of the fan during a preset delay period. The preset delay period is the period during which the fan is controlled by the first constant air volume control strategy until the first stable condition is met, and then the first constant air volume control strategy continues to be run.

[0033] It should be noted that the first constant air volume control strategy is a control strategy that periodically adjusts the fan speed according to the first control cycle to ensure a constant air volume output from the air outlet of the air conditioning equipment where the fan is located.

[0034] In some implementations, periodically adjusting the fan speed according to a first control cycle may include: periodically acquiring the actual and target characteristic values ​​of the fan characteristic parameters according to the first control cycle, that is, acquiring the current actual and target characteristic values ​​of the fan characteristic parameters once every T1 time interval, where T1 is the first control cycle; after each acquisition of the actual and target characteristic values ​​of the fan characteristic parameters, adjusting the fan speed according to the magnitude relationship between the currently acquired actual and target characteristic values.

[0035] In some implementations, the characteristic parameters of the fan can be any of the following parameters of the fan: total power of the fan, total current of the negative bus, torque, magnitude of the sum of dq-axis current vectors, actual q-axis current (when id=0 control), square of the magnitude of the sum of dq-axis current vectors, square of the magnitude of the sum of dq-axis voltage vectors, magnitude of the sum of dq-axis voltage vectors, etc.

[0036] In some implementations, the current actual characteristic value of the fan characteristic parameter can be obtained by calculating the detection data from the detection circuit. Taking the fan motor torque as an example, the actual value i of the quadrature-axis current detected by the fan can be obtained through the detection circuit. q and the actual value of the direct-axis current i d The measured data is used for calculation to obtain the actual motor torque T', which can be based on the motor current i. q i d The motor parameters are calculated using the following formula: T'=1.5P(Ke+(Ld-Lq)*i d )i qLd and Lq are the stator d-axis inductances and q-axis inductances of the fan, respectively, and Ke is the stator winding flux linkage.

[0037] In some implementations, obtaining the current target characteristic value of the fan's characteristic parameters can be achieved by: acquiring the fan's current actual speed and current target airflow; inputting the current target airflow and current actual speed into a pre-established relational model; and obtaining the current target characteristic value of the fan's characteristic parameters through the relational model. The relational model represents the mapping relationship between the fan speed and the characteristic parameters under different target airflows. It can be understood that the current target airflow is the airflow level set according to user needs, that is, the constant airflow desired by the user.

[0038] In some implementations, the pre-established relational model consists of multiple curve models corresponding one-to-one with various preset candidate airflow values. Each curve model represents the mapping relationship between the fan speed and the fan characteristic parameters under that candidate airflow value. Multiple fan speed values ​​and multiple characteristic values ​​of the fan characteristic parameters are obtained for that candidate airflow value, and a curve model for that candidate airflow value is established based on these values. It is understood that the multiple fan speed values ​​and multiple characteristic values ​​of the fan characteristic parameters under that candidate airflow value are obtained by adjusting the static pressure in the duct and the fan speed of the air conditioning prototype in a laboratory environment.

[0039] In other implementations, the pre-established relational model is a surface model established for a continuous air volume range. This surface model represents the mapping relationship between air volume, fan speed and fan characteristic parameters within the continuous air volume range. The current target air volume can be any air volume value within the continuous air volume range.

[0040] In some implementations, obtaining the current actual speed of the fan includes: after sampling the actual three-phase current value of the fan, performing a coordinate transformation on the actual three-phase current value of the fan to obtain the actual two-phase current value in a two-phase static coordinate system; and estimating the rotor angle and speed of the fan based on the actual two-phase current value in the two-phase static coordinate system and the given two-phase voltage value to obtain the current actual speed of the fan.

[0041] In some implementations, adjusting the fan speed based on the relationship between the currently acquired actual characteristic value and the target characteristic value includes: determining an effective voltage vector for the fan based on the relationship between the current characteristic value and the target characteristic value; outputting the effective voltage vector to the fan to adjust the actual characteristic value of the fan's characteristic parameters, thereby changing the fan's output capacity and thus changing the fan's actual speed. After repeatedly adjusting the actual characteristic value of the fan's characteristic parameters until a first stability condition is met, constant airflow output of the fan is indirectly achieved. The first stability condition is that the actual characteristic value of the fan's characteristic parameters is equal to the target characteristic value. In other words, when the fan is controlled to maintain constant airflow according to the first constant airflow control strategy until the actual characteristic value of the fan's characteristic parameters is equal to the target characteristic value, it signifies that the fan has first achieved stable constant airflow output, i.e., the first stability condition is met.

[0042] Understandably, after each acquisition of actual feature values ​​and calculation of target feature values, the deviation of the currently acquired actual feature value from the currently calculated target feature value is determined, and a PI (proportional-integral) adjustment is applied to the deviation value to obtain the current vector and amplitude. The current vector and amplitude refer to the vector amplitudes of the d-axis current setpoint id* and the q-axis current setpoint iq*, which are... Next, the actual eigenvalues ​​of the characteristic parameters are adjusted according to the current vector and amplitude so that, after at least one adjustment, the actual eigenvalues ​​of the characteristic parameters are equal to the target eigenvalues.

[0043] For example, the current vector and magnitude are processed by the MTPA (maximum torque per ampere) algorithm and converted into d-axis current setpoints and q-axis current setpoints. The d-axis and q-axis current setpoints are then controlled by FOC (Field-Oriented Control) to output an effective voltage vector to the fan motor, so that the fan motor can adjust its output capability according to the input effective voltage vector, that is, adjust the actual characteristic value.

[0044] In other implementations, when the fan is controlled to maintain a constant airflow according to the first constant airflow control strategy until the actual characteristic value of the fan characteristic parameter is within the fluctuation range of the characteristic value corresponding to the current target airflow, it indicates that the fan has achieved stable constant airflow output for the first time, that is, the first stability condition is met.

[0045] like Figure 2As shown, the characteristic value fluctuation band is set based on the preset fluctuation bandwidth and the curve model of the current target airflow. Different currently set airflow levels result in different characteristic value fluctuation bands. The upper-biased fluctuation curve K1 and the lower-biased fluctuation curve K2 of the current target airflow are determined according to the preset fluctuation bandwidth and the curve model of the current target airflow. The area between the upper-biased fluctuation curve K1 and the curve model is the upper-biased fluctuation band of the target characteristic value, and the area between the curve model and the lower-biased fluctuation curve K2 is the lower-biased fluctuation band of the target characteristic value. The upper-biased and lower-biased fluctuation bands together constitute the characteristic value fluctuation band of the current target airflow.

[0046] To determine whether the actual characteristic value of the fan's characteristic parameters falls within the characteristic value fluctuation band of the current target airflow, during the constant airflow control process of the fan according to the first constant airflow control strategy before a preset delay period, the following process can be performed for each acquired target characteristic value and actual characteristic value: Based on the currently acquired target characteristic value, determine the upper and lower offset thresholds used for the current time on the characteristic value fluctuation band corresponding to the current target airflow; compare the currently acquired actual characteristic value with the upper and lower offset thresholds used for the current time on the characteristic value fluctuation band; if the currently acquired actual characteristic value does not exceed the upper and lower offset thresholds used for the current time on the characteristic value fluctuation band, it indicates that the actual characteristic value of the fan's characteristic parameters falls within the characteristic value fluctuation band corresponding to the current target airflow. That is, it needs to satisfy: m i_δdown ≦m i ≦m i_δup , where m i m represents the actual feature value obtained in the current iteration. i_δdown m i_δup Used for the upper and lower thresholds of the current iteration.

[0047] More specifically, if the actual characteristic value obtained in the current iteration does not exceed the upper and lower bias thresholds on the characteristic value fluctuation band corresponding to the current target air volume, while the actual characteristic value obtained in the previous iteration exceeds the upper or lower bias threshold on the characteristic value fluctuation band, then the fan has reached a stable constant air volume output for the first time, which means that the first stability condition is met.

[0048] In some implementations, it is not necessary to pre-establish curve functions for the upper and lower deviation fluctuation curves K1 and K2 of the characteristic value fluctuation band for the current target air volume. Instead, a preset fluctuation bandwidth needs to be written into the controller of the air conditioning equipment. The upper and lower deviation thresholds for each target characteristic value are directly based on the preset fluctuation bandwidth δ and the currently acquired target characteristic value m. i The upper bias threshold m is calculated. i_δup =m i (1+δ), lower bias threshold m i_δdown =m i(1-δ), 0≤δ≤1.

[0049] In other implementations, it is necessary to pre-establish curve functions for the upper-biased fluctuation curve K1 and the lower-biased fluctuation curve K2 of the characteristic value fluctuation band for the current target airflow. The curve functions for the upper-biased fluctuation curve K1 and the lower-biased fluctuation curve K2 are established based on the preset fluctuation bandwidth and curve model. The curve functions for the upper-biased fluctuation curve K1 and the lower-biased fluctuation curve K2 are written into the controller of the air conditioning equipment. For example, the function expression of the curve model of the current target airflow is m. i =F j (n i The function of the upper-biased oscillation curve is m. i_δup =F j_δup (n i The function of the lower skewed oscillation curve is m. i_δdown =F j_δdown (n i ), where m i These are the characteristic parameters of the fan, where i is an integer (representing the number of sampling points), and j is the current target air volume determined according to the requirements. The upper and lower threshold values ​​of each target characteristic value are calculated by inputting the current actual speed to the curve function corresponding to the upper and lower fluctuation curves.

[0050] In step S101, after the fan is controlled with constant air volume according to the first constant air volume control strategy until the first stability condition is met, the first constant air volume control strategy continues to run for a preset delay period. That is, after the constant air volume output is stabilized for the first time, the fan is controlled with constant air volume according to the first constant air volume control strategy for a preset delay period. The operating data generated by the fan being controlled with constant air volume according to the first constant air volume control strategy during the preset delay period is obtained. Based on the operating data during the preset delay period, it is determined whether the constant air volume control of the fan according to the first constant air volume control strategy meets the second stability condition.

[0051] In some implementations, the operating data within the preset delay period includes the actual characteristic values ​​of the fan characteristic parameters sampled multiple times within the preset delay period. To determine whether constant airflow control of the fan according to the first constant airflow control strategy satisfies the second stability condition, before identifying the change cycle of the duct system where the fan is located, the process may further include: acquiring the number of times the actual characteristic value of the fan characteristic parameter crosses the characteristic value fluctuation band within the preset delay period; if the number of times the actual characteristic value crosses the characteristic value fluctuation band within the preset delay period reaches a preset threshold, it indicates that constant airflow control of the fan according to the first constant airflow control strategy does not satisfy the second stability condition; if the number of times the actual characteristic value crosses the characteristic value fluctuation band within the preset delay period does not reach the preset threshold, it indicates that constant airflow control of the fan according to the first constant airflow control strategy can satisfy the second stability condition.

[0052] Understandably, the preset number of times threshold can be set to a positive integer according to the actual needs for the stability of constant wind control, such as 1 time, 2 times, or 3 times, etc.

[0053] In some implementations, obtaining the number of times the actual characteristic value of the wind turbine characteristic parameter crosses the characteristic value fluctuation band within a preset delay period includes: within the preset delay period, if the actual characteristic value of the wind turbine characteristic parameter changes from above the upper fluctuation band to below the lower fluctuation band, recording one instance of the actual characteristic value of the wind turbine characteristic parameter crossing the characteristic value fluctuation band; within the preset delay period, if the actual characteristic value of the wind turbine characteristic parameter changes from below the lower fluctuation band to above the upper fluctuation band, recording another instance of the actual characteristic value of the wind turbine characteristic parameter crossing the characteristic value fluctuation band.

[0054] In other embodiments, obtaining the number of times the actual characteristic value of the wind turbine characteristic parameter crosses the characteristic value fluctuation band within a preset delay period includes: within the preset delay period, if the actual characteristic value of the wind turbine characteristic parameter changes from above the upper fluctuation band to below the lower fluctuation band, and then changes from below the lower fluctuation band to above the upper fluctuation band, recording one instance of the actual characteristic value of the wind turbine characteristic parameter crossing the characteristic value fluctuation band.

[0055] In some other embodiments, the number of times the actual characteristic value of the wind turbine characteristic parameter crosses the characteristic value fluctuation band within a preset delay period includes: within the preset delay period, if the actual characteristic value of the wind turbine characteristic parameter changes from below the lower deviation fluctuation band to above the upper deviation fluctuation band, and then changes from above the upper deviation fluctuation band to below the lower deviation fluctuation band, a single instance of the actual characteristic value of the wind turbine characteristic parameter crossing the characteristic value fluctuation band is recorded.

[0056] More specifically, in some implementations, during the process of controlling the fan with constant airflow according to the first constant airflow control strategy within a preset delay period, the actual characteristic value and target characteristic value of the fan characteristic parameters are periodically acquired; for each target characteristic value acquired within the preset delay period, based on the preset fluctuation bandwidth δ and the target characteristic value m acquired in the current iteration... i Determine the upper bias threshold m on the eigenvalue fluctuation band for the current iteration. i (1+δ) and the lower bias threshold m i (1-δ), 0 < δ < 1. (Alternatively, input the target feature value acquired in the current iteration into the pre-established upper and lower skew fluctuation curves to determine the upper and lower skew thresholds used for the current iteration on the feature value fluctuation band corresponding to the current target air volume, refer to...) Figure 2(As shown); compare the current actual feature value with the upper and lower thresholds used for the current feature value fluctuation band. If the current actual feature value exceeds the first fluctuation threshold used for the current feature value fluctuation band and the previous actual feature value did not exceed the first fluctuation threshold used for the previous feature value fluctuation band, then when an actual feature value exceeding the second fluctuation threshold is obtained after the current one, record that the actual feature value of the wind turbine feature parameter crosses the feature value fluctuation band. Here, one of the first fluctuation threshold and the second fluctuation threshold is the upper threshold and the other is the lower threshold, or the first fluctuation threshold and the second fluctuation threshold are both the upper threshold or the lower threshold.

[0057] In some implementations, the preset fluctuation bandwidth δ satisfies 0 < δ < 0.5.

[0058] In some further embodiments, to determine whether the constant airflow control of the fan according to the first constant airflow control strategy satisfies the second stability condition, before identifying the change cycle of the duct system where the fan is located, the method may further include: sampling the actual characteristic values ​​of the fan characteristic parameters multiple times within a preset delay period. If each actual characteristic value sampled within the preset delay period is within the characteristic value fluctuation band corresponding to the current target airflow, then the second stability condition is satisfied; otherwise, the second stability condition is not satisfied. Specifically, for each actual characteristic value sampled within the preset delay period, it is determined whether the actual characteristic value is greater than the upper bias threshold used for the current time in the characteristic value fluctuation band and whether it is less than the lower bias threshold used for the current time in the characteristic value fluctuation band. If both are true, then the actual characteristic value is within the characteristic value fluctuation band corresponding to the current target airflow.

[0059] It is understandable that, since the constant airflow control of the fan according to the first constant airflow control strategy requires periodically acquiring the actual characteristic values ​​of the fan's characteristic parameters according to the first control cycle, in some embodiments, in order to obtain the actual characteristic values ​​of the fan's characteristic parameters sampled multiple times within a preset delay period, it is only necessary to record the actual characteristic values ​​acquired each time within the preset delay period for constant airflow control of the fan. In other embodiments, logic for acquiring the fan's operating data within the preset delay period can also be designed separately. For example, during the process of constant airflow control of the fan according to the first constant airflow control strategy, the actual characteristic values ​​of the fan's characteristic parameters are sampled according to a preset sampling period, wherein the preset sampling period is different from the first control period.

[0060] Of course, in actual implementation, the operating data of the fan during the preset delay period is not limited to the actual characteristic value of the fan characteristic parameters sampled, but can also be the estimated actual air volume. If the estimated actual air volume is stable within the preset fluctuation range of the current target air volume, it indicates that the constant air volume control of the fan according to the first constant air volume control strategy meets the second stability condition; otherwise, the second stability condition is not met.

[0061] Understandably, if the second stability condition is met when the fan is controlled by the first constant air volume control strategy, it means that the change cycle of the duct system where the fan is located matches the first constant air volume control strategy. Therefore, there is no need to change the constant air volume control strategy for the fan, and the fan can continue to be controlled by the first constant air volume control strategy. If the second stability condition is not met, it means that the change cycle of the duct system where the fan is located does not match the first constant air volume control strategy, which will lead to poor stability of constant air volume control. In this case, the following steps S102 to S103 need to be executed to improve the stability of constant air volume control.

[0062] It should be noted that the air duct system where the fan is located is determined by the design of the air conditioning equipment. Different models of air conditioning equipment have different structures such as motors, fan blades, and volutes, which determine the differences in their air duct systems. The air duct system where the fan is located will undergo periodic changes, and the factors that cause the periodic changes in the air duct system where the fan is located include the cyclical oscillation of the air outlet swing mechanism of the air conditioning equipment.

[0063] S102: If, based on the operating data, it is determined that the constant air volume control of the fan according to the first constant air volume control strategy does not meet the second stability condition, the change cycle of the air duct system where the fan is located is identified.

[0064] In some implementations, the cycle of change in the duct system where the fan is located can be identified based on the load changes in the duct system.

[0065] In some implementations, identifying the change cycle of the duct system where the fan is located based on the load change of the duct system can include: obtaining the time span between two adjacent crossings of the characteristic value fluctuation zone of the fan characteristic parameter; and determining the change cycle based on the time span, wherein the size of the time span characterizes the length of the periodic change of the load of the duct system where the fan is located, and therefore, the change cycle of the duct system can be determined based on the time span.

[0066] In some implementations, after a preset delay period, the actual characteristic value of the wind turbine characteristic parameter is recorded as the first moment when it crosses the characteristic value fluctuation band for the first time; after the preset delay period, the actual characteristic value of the wind turbine characteristic parameter is recorded as the second moment when it crosses the characteristic fluctuation band for the second time; the time span is determined based on the time difference between the second moment and the first moment.

[0067] It is understandable that the characteristic value fluctuation band is established for the curve model of the current target air volume. The curve model of the current target air volume represents the mapping relationship between the fan speed and the fan characteristic parameters under the current target air volume. The curve model is used to obtain the target characteristic values ​​of the fan characteristic parameters required to perform constant air volume control on the fan according to the first constant air volume control strategy.

[0068] Understandably, depending on the definition of the traversal of the characteristic value fluctuation band, the method for determining the change period based on the time span will differ accordingly:

[0069] In some implementations, if the actual characteristic value of the wind turbine characteristic parameter changes from above the upper deviation fluctuation band to below the lower deviation fluctuation band, or changes from below the lower deviation fluctuation band to above the upper deviation fluctuation band, indicating that the actual characteristic value of the wind turbine characteristic parameter crosses the characteristic value fluctuation band, then twice the time span is taken as the change period.

[0070] like Figure 3 As shown, twice the time span is taken as the change period, that is, the change period is calculated as follows: ΔT=2*(t4-t3), where ΔT is the change period, t1 is the moment when the constant air volume output is first stabilized, t2 is the moment when the preset delay period ends, t3 is the moment when the actual characteristic value crosses the characteristic value fluctuation band for the first time after the preset delay period, t4 is the moment when the actual characteristic value crosses the characteristic value fluctuation band for the second time after the preset delay period, and t4-t3 is the time span of the actual characteristic value crossing the characteristic value fluctuation band between two adjacent times.

[0071] like Figure 3As shown, it can be understood that after determining that the second stability condition is not met, the first constant air volume control strategy continues to run for a period of time, and after determining that the second stability condition is not met, the fan continues to be controlled with constant air volume according to the first constant air volume control strategy: after each acquisition of actual feature value and target feature value, the actual feature value acquired this time is compared with the upper and lower bias thresholds used for the current time on the feature value fluctuation band corresponding to the current target air volume (the determination method of the upper and lower bias thresholds used for the current time is referred to the above implementation method, and will not be repeated here for the sake of brevity). After time t2, the actual feature value acquired first exceeds the first fluctuation threshold used for the current time on the feature value fluctuation band corresponding to the current target air volume, and then exceeds the second fluctuation threshold used for the current time on the feature value fluctuation band. The time when the second fluctuation threshold is exceeded is recorded as the time t3 when the first feature value fluctuation band is crossed. If the actual feature value obtained after time t3 exceeds the first fluctuation threshold used for the current time on the feature value fluctuation band, then the time when the actual feature value is obtained for the current time is recorded as the time t4 when the feature value fluctuation band is crossed for the second time. Among the first fluctuation threshold and the second fluctuation threshold, one is the upper bias threshold and the other is the lower bias threshold.

[0072] In other embodiments, if the actual characteristic value of the wind turbine characteristic parameter changes sequentially from above the upper deviation fluctuation band to below the lower deviation fluctuation band and above the upper deviation fluctuation band, or changes sequentially from below the lower deviation fluctuation band to above the upper deviation fluctuation band and below the lower deviation fluctuation band, indicating that the actual characteristic value of the wind turbine characteristic parameter crosses the characteristic value fluctuation band, then the time span is taken as the change period.

[0073] like Figure 4 As shown, the time span is taken as the change period, that is, the change period is calculated as follows: ΔT=T4-T3, where ΔT is the change period of the air duct system, t1 is the moment when the first stability is reached, t2 is the moment when the preset delay period ends, t3 is the moment when the actual characteristic value crosses the characteristic value fluctuation zone for the first time after the preset delay period, and t4 is the moment when the actual characteristic value crosses the characteristic value fluctuation zone for the second time after the preset delay period. t4-t3 is the time span of the actual characteristic value crossing the characteristic value fluctuation zone in two adjacent times.

[0074] like Figure 4As shown, it can be understood that after determining that the second stability condition is not met, the first constant air volume control strategy continues to run for a period of time, and after determining that the second stability condition is not met, the fan continues to be controlled with constant air volume according to the first constant air volume control strategy: after each acquisition of actual feature value and target feature value, the actual feature value acquired this time is compared with the upper and lower bias thresholds used for the current time on the feature value fluctuation band corresponding to the current target air volume (the determination method of the upper and lower bias thresholds used for the current time is referred to the above implementation method, and will not be repeated here for the sake of brevity). After time t2, the actual feature value acquired first exceeds the first fluctuation threshold used for the current time on the feature value fluctuation band corresponding to the current target air volume, and then exceeds the second fluctuation threshold used for the current time on the feature value fluctuation band. The time when the second fluctuation threshold is exceeded is recorded as the time t3 when the first feature value fluctuation band is crossed. If the actual feature value obtained after time t3 first exceeds the first fluctuation threshold used for the current time on the feature value fluctuation band, and then exceeds the second fluctuation threshold used for the current time on the feature value fluctuation band, then the time when the actual feature value is obtained for the current time is recorded as the time t4 when the feature value fluctuation band is crossed for the second time. Among the first fluctuation threshold and the second fluctuation threshold, one is the upper bias threshold and the other is the lower bias threshold.

[0075] S103: Adjust the constant air volume control strategy for the fan according to the change cycle, and perform constant air volume control on the fan according to the adjusted second constant air volume control strategy.

[0076] In some implementations, in S103, adjusting the constant air volume control strategy for the fan according to the change cycle includes: adjusting the control cycle for constant air volume control of the fan to a second control cycle that matches the change cycle; and performing constant air volume control of the fan according to the adjusted second constant air volume control strategy, including: periodically adjusting the fan speed according to the second control cycle, wherein the second control cycle is different from the first control cycle and the second control cycle matches the change cycle.

[0077] In order to match the second control cycle with the change cycle, in some embodiments, the constant air volume control strategy for the fan is adjusted according to the change cycle, including: determining the second control cycle according to a preset proportional coefficient and the change cycle, wherein the second control cycle and the change cycle satisfy a linear relationship, and the second control cycle is greater than or equal to the change cycle; and adjusting the control cycle for constant air volume control of the fan from the first control cycle to the second control cycle.

[0078] It is understandable that the second control cycle can be determined based on the preset proportional coefficient and the change cycle, and the following method can be used:

[0079] T2 = k * ΔT;

[0080] T2 is the second control cycle, k is the preset proportional coefficient, k is a positive integer greater than or equal to 1, and ΔT is the change cycle of the air duct system. By adjusting the control cycle of the constant air volume control of the fan, the control cycle of the constant air volume control is matched with the change cycle of the air duct system, so as to suppress the periodic changes of the air duct system and improve the stability of the constant air volume control.

[0081] It should be noted that after adjusting the control cycle for constant airflow control of the fan from the first control cycle to the second control cycle, the only change in the control cycle is the adjustment of the fan speed according to the second control cycle. The control logic for adjusting the fan speed in each control cycle is the same as that in the first constant airflow control strategy. That is, adjusting the fan speed according to the second control cycle includes: periodically acquiring the actual and target characteristic values ​​of the fan characteristic parameters according to the second control cycle, that is, sampling the actual and target characteristic values ​​of the fan characteristic parameters every T2 time interval, where T2 is the second control cycle; after each acquisition of the actual and target characteristic values ​​of the fan characteristic parameters, adjusting the fan speed according to the relationship between the current acquired actual and target characteristic values. More implementation details of periodically adjusting the fan speed according to the second control cycle can be found in the previous text, and will not be repeated here for the sake of brevity.

[0082] In other embodiments, step S103, adjusting the constant airflow control strategy for the fan according to the change cycle, includes: obtaining the actual rotational speed of the fan within the change cycle; and using the actual rotational speed as the target rotational speed for constant airflow control of the fan. Performing constant airflow control on the fan according to the adjusted second constant airflow control strategy includes: performing constant airflow control on the fan based on the target rotational speed, so that the actual rotational speed of the fan remains at the target rotational speed, thereby keeping the output airflow at the outlet relatively constant and improving the stability of the constant airflow control.

[0083] It is understood that the actual rotational speed of the fan within a variation cycle can be the average rotational speed over at least one variation cycle. Therefore, in some embodiments, obtaining the actual rotational speed of the fan within a variation cycle may include: obtaining multiple rotational speed sample values ​​of the fan within at least one variation cycle; and calculating the average of the multiple rotational speed sample values ​​of the fan within at least one variation cycle to obtain the actual rotational speed of the fan within the variation cycle. In other embodiments, a maximum rotational speed sample value and a minimum rotational speed sample value may be obtained from the multiple rotational speed sample values ​​within at least one variation cycle, and the actual rotational speed of the fan within the variation cycle may be calculated by averaging the maximum and minimum rotational speed sample values.

[0084] like Figure 5As shown, after at least one cycle following time t4, the actual rotational speed of the fan during the cycle can be calculated.

[0085] Understandably, since the fan is controlled to maintain a constant airflow according to the first constant wind control strategy, it is necessary to obtain the fan's current actual speed according to the first control cycle. Therefore, in some embodiments, in order to obtain multiple speed sampling values ​​of the fan within at least one change cycle, the current actual speed used to determine the target feature value is recorded each time within at least one change cycle after a preset delay period, thereby obtaining multiple speed sampling values ​​within at least one change cycle. In other embodiments, the current actual speed of the fan can also be sampled according to a preset sampling cycle within at least one change cycle after a preset delay period to obtain multiple speed sampling values ​​within at least one change cycle.

[0086] In some other embodiments, step S103, adjusting the constant air volume control strategy for the fan according to the change cycle, includes: obtaining the target characteristic value for constant air volume control acquired by the fan each time within the change cycle; calculating the average of the target characteristic values ​​acquired each time within the change cycle to obtain the target characteristic average; and performing constant air volume control on the fan according to the adjusted second constant air volume control strategy, including: performing constant air volume control on the fan according to the calculated target characteristic average, so that the actual characteristic value of the fan remains at the target characteristic average. This embodiment avoids fluctuations in constant air volume control by fixing the target characteristic value, thereby improving the stability of constant air volume control.

[0087] Based on the same inventive concept, the present invention also provides a constant air volume control device for a fan, such as... Figure 6 As shown, the constant air volume control device includes:

[0088] The data acquisition unit 601 is used to acquire the operating data of the fan during a preset delay period. The preset delay period is the period during which the fan is controlled by the first constant air volume control strategy until the first stable condition is met, and the first constant air volume control strategy continues to be run.

[0089] The cycle identification unit 602 is used to identify the change cycle of the air duct system where the fan is located if it is determined from the operating data that the constant air volume control of the fan does not meet the second stability condition.

[0090] Strategy adjustment unit 603 is used to adjust the constant air volume control strategy for the fan according to the change cycle;

[0091] The control execution unit 604 is used to control the constant air volume of the fan according to the adjusted second constant air control strategy.

[0092] In some implementations, the first constant air volume control strategy is a control strategy that periodically adjusts the fan speed according to a first control cycle. The control execution unit 604 is used to periodically adjust the fan speed according to a second control cycle, the second control cycle being different from the first control cycle and matching the change cycle.

[0093] In some implementations, the strategy adjustment unit 603 is used to: determine a second control period based on a preset proportional coefficient and a change period, wherein the second control period and the change period satisfy a linear relationship, and the second control period is greater than or equal to the change period; and adjust the control period for constant air volume control of the fan from the first control period to the second control period.

[0094] In some embodiments, the strategy adjustment unit 603 includes: a speed acquisition subunit for acquiring the actual speed of the fan during the change cycle; a subunit for using the actual speed as the target speed for constant airflow control of the fan; and a control execution unit 604 for performing constant airflow control of the fan according to the target speed, so that the actual speed of the fan is maintained at the target speed.

[0095] In some implementations, the speed acquisition subunit is used to: acquire multiple speed sample values ​​of the fan within at least one variation cycle; and calculate the average value of the multiple speed sample values ​​to obtain the actual speed.

[0096] In some embodiments, the periodicity identification unit 602 includes:

[0097] The span acquisition subunit is used to acquire the time span of the actual characteristic value of the fan characteristic parameter in two adjacent crossings of the characteristic value fluctuation band. The characteristic value fluctuation band is established by the curve model for the current target air volume. The curve model represents the mapping relationship between the fan speed and the fan characteristic parameter under the current target air volume. The curve model is used to acquire the target characteristic value of the fan characteristic parameter required to perform constant air volume control on the fan according to the first constant air volume control strategy.

[0098] The period determination sub-unit is used to determine the change period based on the time span.

[0099] In some implementations, the eigenvalue fluctuation band includes an upper-biased fluctuation band and a lower-biased fluctuation band of the target eigenvalue, and the periodic determination sub-unit is used for:

[0100] If the actual characteristic value of the wind turbine's characteristic parameter changes from above the upper deviation fluctuation band to below the lower deviation fluctuation band, or changes from below the lower deviation fluctuation band to above the upper deviation fluctuation band, it indicates that the actual characteristic value of the wind turbine's characteristic parameter has crossed the characteristic value fluctuation band.

[0101] The change cycle is defined as twice the time span.

[0102] In some implementations, the eigenvalue fluctuation band includes an upper-biased fluctuation band and a lower-biased fluctuation band of the target eigenvalue, and the periodic determination sub-unit is used for:

[0103] If the actual characteristic value of the wind turbine's characteristic parameter changes sequentially from above the upper deviation fluctuation band to below the lower deviation fluctuation band and above the upper deviation fluctuation band, or changes sequentially from below the lower deviation fluctuation band to above the upper deviation fluctuation band and below the lower deviation fluctuation band, it indicates that the actual characteristic value of the wind turbine's characteristic parameter crosses the characteristic value fluctuation band.

[0104] Use time span as the cycle of change.

[0105] In some implementations, the span acquisition subunit is used to: record a first moment when the actual characteristic value of the wind turbine characteristic parameter crosses the characteristic value fluctuation band for the first time after a preset delay period; record a second moment when the actual characteristic value of the wind turbine characteristic parameter crosses the characteristic fluctuation band for the second time after a preset delay period; and determine the time span based on the time difference between the second moment and the first moment.

[0106] In some embodiments, the operating data within the preset delay period includes the actual characteristic values ​​of the wind turbine characteristic parameters sampled within the preset delay period; the device further includes:

[0107] The number of times acquisition unit is used to acquire the number of times the actual characteristic value of the wind turbine characteristic parameter crosses the characteristic value fluctuation band within a preset delay period;

[0108] The count judgment unit is used to indicate that if the count reaches a preset count threshold, it means that the constant air volume control of the fan according to the first constant air volume control strategy does not meet the second stability condition.

[0109] In some embodiments, the device further includes:

[0110] The feature value acquisition unit is used to determine the upper and lower bias thresholds on the feature value fluctuation band for the current time based on the target feature value and the preset fluctuation bandwidth, for each acquired target feature value and actual feature value, during the process of constant air volume control of the fan according to the first constant air volume control strategy.

[0111] The eigenvalue comparison unit is used to compare the actual eigenvalue obtained in the current iteration with the upper and lower threshold values ​​used for the current iteration on the eigenvalue fluctuation band.

[0112] The stability judgment unit is used to indicate that if the actual feature value obtained in the current iteration does not exceed the upper and lower bias thresholds on the feature value fluctuation band used for the current iteration, it means that the constant air volume control of the fan according to the first constant air volume control strategy meets the first stability condition.

[0113] The specific functions of each functional unit in the above-mentioned device have been described in detail in the constant air volume control method for fans provided in some embodiments of the present invention, and will not be elaborated here.

[0114] Based on the same inventive concept, embodiments of the present invention also provide an air conditioning device, which includes a fan, such as... Figure 7 As shown, the air conditioning device further includes: a processor 702; and a memory 704 for storing executable instructions of the processor 702, wherein the processor 702 is configured to execute the instructions to implement the constant air volume control method for the fan described in any of the above embodiments.

[0115] Among them, Figure 7 In this document, a bus architecture (represented by bus 700) is used. Bus 700 may include any number of interconnected buses and bridges, linking various circuits including one or more processors represented by processor 702 and memory represented by memory 704. Bus 700 may also link various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further herein. Bus interface 705 provides an interface between bus 700 and receiver 701 and transmitter 703. Receiver 701 and transmitter 703 may be the same element, i.e., a transceiver, providing a unit for communicating with various other devices over a transmission medium. Processor 702 is responsible for managing bus 700 and general processing, while memory 704 can be used to store data used by processor 702 during operation.

[0116] Based on the same inventive concept, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the constant air volume control method for a fan as described in any of the above embodiments.

[0117] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 Devices that specify the functions in one or more boxes.

[0118] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including an instruction device, which is implemented in a process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0119] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0120] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0121] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

[0122] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for controlling the constant air volume of a fan, characterized in that, include: The operation data of the fan is obtained within a preset delay period. The preset delay period is the period after the fan is controlled with constant air volume according to the first constant air volume control strategy until the first stable condition is met, and the first constant air volume control strategy continues to be run. If, based on the operating data, it is determined that the constant air volume control of the fan does not meet the second stability condition, the change cycle of the air duct system where the fan is located is identified. The constant air volume control strategy for the fan is adjusted according to the change cycle, and the fan is controlled with constant air volume according to the adjusted second constant air volume control strategy.

2. The method as described in claim 1, characterized in that, The first constant airflow control strategy is a control strategy that periodically adjusts the fan speed according to a first control cycle. The step of controlling the fan with constant airflow according to the adjusted second constant airflow control strategy includes: The fan speed is periodically adjusted according to a second control cycle, which is different from the first control cycle and matches the change cycle.

3. The method as described in claim 2, characterized in that, The constant air volume control strategy for the fan adjusted according to the change cycle includes: The second control period is determined based on a preset proportional coefficient and the change period. The second control period and the change period have a linear relationship, and the second control period is greater than or equal to the change period. The control cycle for constant airflow control of the fan is adjusted from the first control cycle to the second control cycle.

4. The method as described in claim 1, characterized in that... The method of adjusting the constant air volume control strategy for the fan according to the change cycle includes: Obtain the actual rotational speed of the fan during the change cycle; The actual rotational speed is used as the target rotational speed for constant airflow control of the fan; The step of controlling the fan with constant air volume according to the adjusted second constant air volume control strategy includes: controlling the fan with constant air volume according to the target speed so that the actual speed of the fan is maintained at the target speed.

5. The method as described in claim 4, characterized in that, The step of obtaining the actual rotational speed of the wind turbine during the change cycle includes: Obtain multiple speed sampling values ​​of the fan during at least one of the said change cycles; The actual rotational speed is obtained by averaging the multiple rotational speed samples.

6. The method according to any one of claims 1-4, characterized in that, The identification of the change cycle of the air duct system where the fan is located includes: The actual characteristic values ​​of the fan characteristic parameters are obtained within the time span of two adjacent crossings of the characteristic value fluctuation band. The characteristic value fluctuation band is established by a curve model for the current target air volume. The curve model represents the mapping relationship between the fan speed and the fan characteristic parameters under the current target air volume. The curve model is used to obtain the target characteristic values ​​of the fan characteristic parameters required for constant air volume control of the fan according to the first constant air volume control strategy. The change period is determined based on the time span.

7. The method as described in claim 6, characterized in that, The eigenvalue fluctuation band includes an upper-biased fluctuation band and a lower-biased fluctuation band of the target eigenvalue, and determining the change period based on the time span includes: If the actual characteristic value of the wind turbine characteristic parameter changes from above the upper deviation fluctuation band to below the lower deviation fluctuation band, or changes from below the lower deviation fluctuation band to above the upper deviation fluctuation band, it indicates that the actual characteristic value of the wind turbine characteristic parameter crosses the characteristic value fluctuation band. The change period is defined as twice the time span.

8. The method as described in claim 6, characterized in that, The eigenvalue fluctuation band includes an upper-biased fluctuation band and a lower-biased fluctuation band of the target eigenvalue, and determining the change period based on the time span includes: If the actual characteristic value of the wind turbine characteristic parameter changes sequentially from above the upper deviation fluctuation band to below the lower deviation fluctuation band and above the upper deviation fluctuation band, or changes sequentially from below the lower deviation fluctuation band to above the upper deviation fluctuation band and below the lower deviation fluctuation band, it indicates that the actual characteristic value of the wind turbine characteristic parameter crosses the characteristic value fluctuation band; The time span is taken as the change period.

9. The method as described in claim 6, characterized in that, The time span of obtaining the actual characteristic value of the wind turbine characteristic parameter during two adjacent crossings of the characteristic value fluctuation band includes: After the preset delay period, the first moment is recorded when the actual characteristic value of the wind turbine characteristic parameter first crosses the characteristic value fluctuation band; After the preset delay period, the actual characteristic value of the wind turbine characteristic parameter is recorded at the second moment when it crosses the characteristic fluctuation band for the second time; The time span is determined based on the time difference between the second time point and the first time point.

10. The method as described in claim 6, characterized in that, The operating data within the preset delay period includes the actual feature values ​​of the wind turbine feature parameters sampled within the preset delay period; Before identifying the change cycle of the duct system where the fan is located, the method further includes: The number of times the actual characteristic value of the wind turbine characteristic parameter crosses the characteristic value fluctuation band within the preset delay period is obtained; If the number of times reaches a preset threshold, it indicates that the second stability condition is not met when the constant air volume control of the fan is performed according to the first constant air volume control strategy.

11. The method as described in claim 6, characterized in that, Before acquiring the operating data of the wind turbine within a preset delay period, the method further includes: During the process of constant air volume control of the fan according to the first constant air volume control strategy, for each acquired target feature value and actual feature value, the upper and lower bias thresholds on the feature value fluctuation band are determined based on the target feature value acquired in the current time and the preset fluctuation bandwidth. The actual feature value obtained in the current iteration is compared with the upper and lower bias thresholds used for the current iteration on the feature value fluctuation band; If the actual feature value obtained in the current iteration does not exceed the upper and lower bias thresholds on the feature value fluctuation band used for the current iteration, it indicates that the constant air volume control of the fan according to the first constant air volume control strategy satisfies the first stability condition.

12. A constant air volume control device for a fan, characterized in that, include: The data acquisition unit is used to acquire the operating data of the fan during a preset delay period. The preset delay period is the period during which the fan is controlled by the first constant air volume control strategy until the first stable condition is met, and the first constant air volume control strategy continues to be run. The period identification unit is used to identify the change period of the air duct system where the fan is located if it is determined from the operating data that the constant air volume control of the fan does not meet the second stability condition. The strategy adjustment unit is used to adjust the constant air volume control strategy for the fan according to the change cycle. The control execution unit is used to control the constant air volume of the fan according to the adjusted second constant air control strategy.

13. An air conditioning device, characterized in that, The air conditioning device, which includes a fan, further includes: a processor; and a memory for storing executable instructions of the processor, wherein the processor is configured to execute the instructions to implement the constant airflow control method for the fan as described in any one of claims 1 to 11.

14. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the constant air volume control method for the fan as described in any one of claims 1 to 11.

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