Motor frequency reduction control method, device, equipment, storage medium and product

Abstract

This disclosure relates to the field of motor frequency conversion technology, specifically to a method, device, equipment, storage medium, and product for motor frequency reduction control. The method includes: acquiring real-time operating data of the motor; obtaining a first frequency reduction speed and a second frequency reduction speed based on the real-time operating data, wherein the first frequency reduction speed represents the motor speed in a first cycle, and the second frequency reduction speed represents the motor speed in a second cycle; adjusting the first frequency reduction speed according to the difference between the first and second frequency reduction speeds to obtain a third frequency reduction speed; and performing frequency reduction control on the motor within the first cycle based on the third frequency reduction speed. When extreme situations such as sudden changes in bus voltage, motor current, or load occur, feedforward control of motor frequency reduction is achieved by superimposing the pre-calculated third frequency reduction speed used for motor frequency reduction onto the subsequent motor speed. Based on this feedforward control, the compressor frequency can be rapidly reduced, reducing machine downtime and maintenance.

Description

Technical Field

[0001] This disclosure relates to the field of motor frequency conversion technology, specifically to motor frequency reduction control methods, devices, equipment, storage media, and products. Background Technology

[0002] In the field of motor frequency conversion algorithms, the current mainstream approach is to use FOC (Field-Oriented Control), also known as vector control, to achieve frequency conversion control of motors in some household appliances, such as air conditioners, refrigerators, and washing machines. FOC is a frequency conversion drive control method that controls a three-phase AC motor by controlling the amplitude and frequency of the inverter's output voltage. It can precisely control the magnitude and direction of the magnetic field, resulting in smooth motor torque, low noise, high efficiency, and high-speed dynamic response.

[0003] When permanent magnet synchronous motors in household appliances such as air conditioners, refrigerators, and washing machines encounter sudden changes in bus voltage, motor current, or load during operation, the relevant technologies generally use speed-current dual closed-loop FOC control to forcibly resist external interference. However, the motor frequency decreases and the speed is too slow to respond quickly enough to resist the interference, which can easily lead to motor failure. Summary of the Invention

[0004] In view of this, the present disclosure provides a motor frequency reduction control method, device, equipment, storage medium and product to solve the problem that when a permanent magnet synchronous motor encounters some sudden events during operation, the motor frequency reduction speed is too slow to respond quickly to resist interference, which easily leads to motor failure.

[0005] In a first aspect, this disclosure provides a method for controlling the frequency reduction of a motor, the method comprising:

[0006] Obtain real-time operating data of the motor; Based on real-time operating data, the first reduced frequency speed and the second reduced frequency speed are obtained, where the first reduced frequency speed represents the motor speed in the first cycle and the second reduced frequency speed represents the motor speed in the second cycle. Based on the difference between the first and second frequency reduction speeds, the first frequency reduction speed is adjusted to obtain the third frequency reduction speed; Based on the third reduced-frequency speed, the motor is controlled to reduce frequency during the first cycle.

[0007] In one optional implementation, the first reduced-frequency speed and the second reduced-frequency speed are obtained based on real-time operating data, including: Determine the reduced-frequency rotation speed under multiple cycles based on real-time operating data; Select the first and second frequency reduction speeds from the frequency reduction speeds.

[0008] In one optional implementation, determining the reduced-frequency rotational speed over multiple cycles based on real-time operating data includes: Obtain the first average value of real-time running data over multiple periods; The first average value is filtered to obtain the second average value; Obtain the first difference between the first average and the second average; The first difference is used for control calculations by a proportional-integral controller to obtain the reduced-frequency speed of the motor in multiple cycles.

[0009] In one optional implementation, obtaining a first difference between a first average and a second average includes: The difference is obtained by subtracting the first average and the second average. The difference is numerically corrected so that the corrected difference is a non-positive number, thus obtaining the first difference value.

[0010] In one optional implementation, the first frequency reduction speed is adjusted based on the difference between the first and second frequency reduction speeds to obtain a third frequency reduction speed, including: Obtain the second difference between the first frequency reduction speed and the second frequency reduction speed; The second difference is compared with the upper limit of the rate of change of the speed difference to obtain the first comparison result; Based on the first comparison result, adjust the first frequency reduction speed and determine the third frequency reduction speed.

[0011] In one optional implementation, adjusting the first frequency reduction speed based on the first comparison result and determining the third frequency reduction speed includes: If the first comparison result indicates that the second difference is greater than the upper limit of the rate of change of the speed difference, then the first speed reduction is adjusted based on the second speed reduction speed and the upper limit of the rate of change of the speed difference, and the third speed reduction speed is determined. If the first comparison result indicates that the second difference is less than the negative of the upper limit of the rate of change of the speed difference, then the first rate of change is adjusted based on the negative of the second rate of change and the upper limit of the rate of change of the speed difference, and the third rate of change is determined.

[0012] In one optional implementation, adjusting the first frequency reduction speed and determining the third frequency reduction speed includes: Adjust the first frequency reduction speed to obtain the adjusted first frequency reduction speed; The adjusted first frequency reduction speed is compared with the first speed threshold to obtain the second comparison result, and the adjusted first frequency reduction speed is compared with the second speed threshold to obtain the third comparison result; Based on the second and third comparison results, the third frequency reduction speed is obtained.

[0013] In one optional implementation, a third reduced-frequency rotational speed is obtained based on the second comparison result and the third comparison result, including: If the second comparison result indicates that the adjusted first frequency reduction speed is greater than the first speed threshold, then the third frequency reduction speed is assigned a preset value; If the third comparison result indicates that the adjusted first frequency reduction speed is less than the second speed threshold, then the third frequency reduction speed is assigned the value of the second speed threshold. If the second comparison result indicates that the adjusted first frequency reduction speed is less than or equal to the first speed threshold, and the third comparison result indicates that the adjusted first frequency reduction speed is greater than or equal to the second speed threshold, then the third frequency reduction speed is assigned the adjusted first frequency reduction speed.

[0014] In one optional implementation, the real-time operating data includes at least one of bus voltage data, preset axial current data, and mechanical power data.

[0015] In one alternative implementation, the real-time operating data includes at least two of the following: bus voltage data, preset axial current data, and mechanical power data.

[0016] In one optional implementation, when the real-time operating data includes at least two of the following: bus voltage data, preset axial current data, and mechanical power data, a third reduced-frequency speed is obtained, including: Based on each real-time operating data point, the corresponding third frequency reduction speed is obtained; The third frequency reduction speed is numerically fused to obtain the fused third frequency reduction speed.

[0017] In one alternative implementation, the method further includes: Obtain the target motor speed; The adjusted motor speed is obtained by superimposing the third reduced-frequency speed with the target motor speed. The actual motor speed is obtained by using the adjusted motor speed in the dual closed-loop control of the field-oriented control.

[0018] Secondly, this disclosure provides a motor frequency reduction control device, the device comprising: The first acquisition module is used to acquire the real-time operating data of the motor; The first obtaining module is used to obtain the first reduced frequency speed and the second reduced frequency speed based on real-time operating data, wherein the first reduced frequency speed represents the motor speed in the first cycle and the second reduced frequency speed represents the motor speed in the second cycle. The adjustment module is used to adjust the first frequency reduction speed according to the difference between the first frequency reduction speed and the second frequency reduction speed to obtain the third frequency reduction speed; The frequency reduction module is used to reduce the frequency of the motor within the first cycle based on the third frequency reduction speed.

[0019] Thirdly, this disclosure provides an electrical device that includes a motor and a controller. The controller includes a memory and a processor, which are communicatively connected. The memory stores computer instructions, and the processor executes the computer instructions to perform the motor frequency reduction control method described in the first aspect or any corresponding embodiment.

[0020] Fourthly, this disclosure provides a computer-readable storage medium storing computer instructions for causing a computer to execute the motor frequency reduction control method of the first aspect or any corresponding embodiment described above.

[0021] Fifthly, this disclosure provides a computer program product, including computer instructions for causing a computer to execute the motor frequency reduction control method described in the first aspect or any corresponding embodiment thereof.

[0022] In this embodiment, by acquiring real-time operating data of the motor, a first reduced-frequency speed and a second reduced-frequency speed are obtained based on the real-time operating data. Then, based on the difference between the first and second reduced-frequency speeds, the first reduced-frequency speed is adjusted to obtain a third reduced-frequency speed. Finally, based on the third reduced-frequency speed, the motor is frequency-reduced within the first cycle. In this way, when extreme situations such as sudden changes in bus voltage, motor current, or load occur, the pre-calculated third reduced-frequency speed for motor frequency reduction is superimposed on the subsequent motor speed to achieve feedforward control of motor frequency reduction. Based on this feedforward control, the compressor frequency can be rapidly reduced, avoiding motor faults such as overcurrent, overvoltage, and stall, reducing machine downtime and maintenance. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the specific embodiments of this disclosure or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of an electrical device according to an embodiment of the present disclosure; Figure 2 This is a schematic flowchart of a motor frequency reduction control method according to an embodiment of the present disclosure; Figure 3 This is a schematic flowchart of another motor frequency reduction control method according to an embodiment of the present disclosure; Figure 4 This is a flowchart illustrating another motor frequency reduction control method according to an embodiment of the present disclosure; Figure 5 This is a complete algorithm schematic diagram of motor frequency reduction control according to an embodiment of the present disclosure; Figure 6 This is a schematic diagram of the algorithm principle for motor frequency reduction control according to an embodiment of the present disclosure; Figure 7 This is a schematic diagram of an algorithm for motor frequency reduction control according to an embodiment of the present disclosure; Figure 8 This is a complete flowchart of the motor frequency reduction control method according to an embodiment of the present disclosure; Figure 9 This is a structural block diagram of a motor frequency reduction control device according to an embodiment of the present disclosure; Figure 10 This is a schematic diagram of the structure of a controller for an electrical device provided in an embodiment of this disclosure. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0026] It is understood that before using the technical solutions disclosed in the various embodiments of this disclosure, users should be informed of the types, scope of use, and usage scenarios of the personal information involved in this disclosure in an appropriate manner in accordance with relevant laws and regulations, and user authorization should be obtained.

[0027] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise expressly specified.

[0028] In the control scenarios of permanent magnet synchronous motors in large appliances (such as air conditioners, refrigerators, washing machines, etc.), when the motor encounters extreme situations such as sudden changes in bus voltage (such as a sudden rise / fall in grid voltage), sudden changes in motor current (such as a precursor to a short circuit in the winding), and sudden changes in load (such as compressor jamming), the motor relies on FOC technology to achieve precise speed regulation. It has the advantages of high efficiency, low noise, and high power density, but the motor frequency decreases slowly, which is not enough to respond quickly to resist interference, and motor failure is likely to occur.

[0029] To address the aforementioned problems, according to an embodiment of this disclosure, a method for controlling motor frequency reduction is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0030] This embodiment provides a motor frequency reduction control method, which can be used in the controllers of electrical appliances, such as air conditioners, refrigerators, and washing machines. Specifically, as shown in the example... Figure 1 As shown, the electrical equipment involved in this embodiment includes: a motor and a controller, wherein the controller performs... Figure 2 The illustrated motor frequency reduction control method flow is used to control the motor. The specific steps of the method flow executed by the controller are as follows: Step S201: Obtain the real-time operating data of the motor.

[0031] Specifically, in this embodiment of the disclosure, the home appliance uses a controller to collect some real-time operating data of the motor, such as bus voltage (Vdc), preset shaft current (e.g., q-axis current), and mechanical power. Furthermore, these real-time operating data are acquired through sensors, such as a voltage sensor collecting bus voltage and a current sensor collecting q-axis current. These real-time operating data are all core indicators characterizing the motor's operating status: bus voltage reflects power supply stability, q-axis current is directly related to torque output, and mechanical power reflects the load size.

[0032] Specifically, during the data acquisition process, real-time operating data can be collected periodically. This period needs to match the motor speed loop period. For example, based on the speed loop T=1ms, real-time operating data can be collected over multiple periods to avoid noise interference from a single period.

[0033] Step S202: Based on real-time operating data, obtain the first reduced frequency speed and the second reduced frequency speed, wherein the first reduced frequency speed represents the motor speed in the first cycle and the second reduced frequency speed represents the motor speed in the second cycle.

[0034] Specifically, in closed-loop control, the difference in control input between adjacent cycles reflects the rate of change of the control signal. Difference analysis can prevent system oscillations caused by sudden changes in control input. In this case, the corresponding reduced-frequency speed can be calculated first using real-time operating data for each cycle. Then, from the reduced-frequency speeds of all cycles, the "ω0 of the current cycle" (the first reduced-frequency speed) and the "ω of the second cycle, such as the previous cycle" can be selected. pre (Second frequency reduction speed), and then based on the first frequency reduction speed and the second frequency reduction speed, the motor feedforward control is realized, thereby achieving the effect of rapid frequency reduction.

[0035] Step S203: Adjust the first frequency reduction speed according to the difference between the first frequency reduction speed and the second frequency reduction speed to obtain the third frequency reduction speed.

[0036] Specifically, after obtaining the first frequency reduction speed ω0 and the second frequency reduction speed ω pre Then, the difference between the two is Δω = ω0 - ω pre The first difference Δω is obtained, and Δω is used to quantify the change in the current frequency reduction speed.

[0037] Then, the first frequency reduction speed ω0 is adjusted based on Δω, for example, by setting a fixed threshold Δω. thr The first frequency reduction speed ω0 and Δω thr The comparison is performed, and the first frequency reduction speed ω0 is adjusted based on the comparison result to obtain the third frequency reduction speed ω1. Alternatively, a segmented limiting method can be used, which divides the range of Δω into multiple continuous intervals and designs different adjustment coefficients / limiting rules for each interval to achieve fine-grained gradient adjustment of ω0. For example, the range of Δω can be divided into multiple intervals, such as: |Δω|≤0.05hz / ms, 0.05<|Δω|≤0.10hz / ms, |Δω|>0.10hz / ms; if |Δω|≤0.05hz / ms: no adjustment, ω1=ω0; if 0.05<|Δω|≤0.10hz / ms: adjust the value of ω0 according to the actual Δω to obtain ω1; if |Δω|>0.10hz / ms: set ω1 to a specific value, such as 0.15hz / ms.

[0038] Step S204: Based on the third reduced-frequency speed, the motor is controlled to reduce frequency within the first cycle.

[0039] Specifically, the third frequency reduction speed ω1 is fed forward into the FOC dual closed-loop control of the motor speed loop to realize the motor frequency reduction within the first cycle of the current 1ms speed loop, achieving a rapid frequency reduction of, for example, 50~150hz / s.

[0040] It should be noted that the speed-current dual closed-loop FOC field-oriented control is the mainstream control architecture for permanent magnet synchronous motors. The speed loop is the outer loop (which can be at the millisecond level), and the current loop is the inner loop (which can be at the microsecond level). Feedforward control is a supplement to the closed-loop control and can improve the control response speed.

[0041] In this embodiment, by acquiring real-time operating data of the motor, a first reduced-frequency speed and a second reduced-frequency speed are obtained based on the real-time operating data. Then, based on the difference between the first and second reduced-frequency speeds, the first reduced-frequency speed is adjusted to obtain a third reduced-frequency speed. Finally, based on the third reduced-frequency speed, the motor is frequency-reduced within the first cycle. In this way, when extreme situations such as sudden changes in bus voltage, motor current, or load occur, the pre-calculated third reduced-frequency speed for motor frequency reduction is superimposed on the subsequent motor speed to achieve feedforward control of motor frequency reduction. Based on this feedforward control, the compressor frequency can be rapidly reduced, avoiding motor faults such as overcurrent, overvoltage, and stall, reducing machine downtime and maintenance.

[0042] This disclosure provides a method for controlling the frequency reduction of a motor, which can be used in the controller of an electrical appliance. Figure 3 This is a flowchart illustrating another motor frequency reduction control method according to an embodiment of the present disclosure, as shown below. Figure 3 As shown, the process includes the following steps: Step S301: Obtain real-time operating data of the motor. For details, please refer to [link / reference]. Figure 2 Step S201 of the illustrated embodiment will not be described again here.

[0043] Step S302: Based on real-time operating data, obtain the first reduced frequency speed and the second reduced frequency speed, wherein the first reduced frequency speed represents the motor speed in the first cycle and the second reduced frequency speed represents the motor speed in the second cycle.

[0044] Specifically, step S302 includes: Step S3021: Determine the reduced-frequency rotation speed under multiple cycles based on real-time operating data; Step S3022: Select the first frequency reduction speed and the second frequency reduction speed from the frequency reduction speeds.

[0045] Specifically, the motor speed loop is continuously periodically controlled (e.g., 1ms / cycle). Based on real-time operating data of bus voltage, current, and mechanical power, the corresponding reduced-frequency speed ω0 is calculated by the PI controller in each cycle, thus forming a reduced-frequency speed sequence of multiple cycles {ω0(n), ω0(n-1), ω0(n-2)...} (n is the current cycle).

[0046] From a multi-cycle frequency reduction speed sequence, ω0 of the current cycle (first cycle) is selected as the first frequency reduction speed, and ω0 of the previous cycle (second cycle) is selected as the first frequency reduction speed. pre =ω0(n-1) is the second frequency reduction rotation speed, which serves as one of the two preferred comparison periods in the embodiments of this disclosure.

[0047] It is important to understand that the rotational speeds of two adjacent cycles are selected for comparison because the parameter changes in adjacent cycles best reflect the real-time rate of change. If an interval cycle is selected, the calculation of the rate of change will lag, making it impossible to achieve the goal of rapid frequency reduction.

[0048] Step S303: Based on the difference between the first and second frequency reduction speeds, the first frequency reduction speed is adjusted to obtain the third frequency reduction speed. For details, please refer to [link to relevant documentation]. Figure 2 Step S203 of the illustrated embodiment will not be described again here.

[0049] Step S304: Based on the third reduced-frequency speed, frequency reduction control is performed on the motor during the first cycle. For details, please refer to [link to relevant documentation]. Figure 2 Step S204 of the illustrated embodiment will not be described again here.

[0050] In this embodiment of the disclosure, the frequency reduction speeds of all preset periods are determined, and then the first frequency reduction speed and the second frequency reduction speed are selected from them. This ensures the data integrity of the speed difference calculation, avoids the deviation in the difference calculation caused by missing data, and improves the accuracy of the first difference.

[0051] As an optional embodiment, step S3021 includes: Step a1: Obtain the first average value of real-time running data over multiple periods; Step a2: Filter the first average value to obtain the second average value; Step a3: Obtain the first difference between the first average and the second average; Step a4: The first difference is processed based on the proportional-integral controller to obtain the reduced-frequency speed of the motor in multiple cycles.

[0052] Specifically, taking the bus voltage as an example of real-time operating data, the first average value Vdc is obtained by taking the average value of the period from 10 to 20 ms. mean This involves averaging multiple millisecond-level velocity cycle data. Since there are many cycles, the first average value, Vdc, is... mean There are also multiple quantities.

[0053] Since the first average value only suppresses high-frequency noise, it may still exhibit slight fluctuations. Therefore, low-pass filtering of the first average value allows for precise determination of whether abrupt changes in the data have occurred (such as a sudden drop in bus voltage). The current filtering time can be 100-200ms to obtain the second average value, Vdc. Fill .

[0054] Low-pass filtering is a common signal processing technique in the control field. It can filter out mid-to-high frequency components in a signal and retain low-frequency trends. It is suitable for extracting the slow-changing trends of motor operating parameters. A filtering time of 100~200ms is a common filtering parameter for voltage / current / power in permanent magnet synchronous motor control.

[0055] Find the first difference between the first and second averages: ΔV = Vdc mean -Vdc Fill The first difference is input into the PI proportional-integral controller, and the output is the reduced frequency speed ω0 for each cycle.

[0056] The first average value is the real-time average (reflecting the current state), and the second average value is the steady-state filtered value (reflecting the normal state). The difference between the two directly quantifies the degree of deviation between the current operating state and the normal state. The larger the absolute value of the difference, the more serious the interference to the motor, providing a quantified interference signal for subsequent PI calculation.

[0057] PI controllers are widely used in motor control for speed loops and current loops. They quickly respond to deviations through the proportional term and eliminate steady-state deviations through the integral term, converting the input deviation signal (first difference) into a controllable output signal (reduced frequency speed).

[0058] In this embodiment of the disclosure, the average value of the multi-cycle real-time running data is taken to effectively suppress high-frequency noise in the motor running data. Then, the average value is filtered to further extract the steady-state trend of the data. Then, based on the first difference between the first average value and the second average value obtained after filtering, the deviation of the motor running parameters is effectively reflected, thereby ensuring the speed and accuracy of the reduced-frequency speed calculation when the second difference is converted into reduced-frequency speed using target control calculation.

[0059] As an optional embodiment, step a3 includes: Step a31: Calculate the difference between the first average and the second average to obtain the difference value; Step a32: Perform numerical correction on the difference so that the corrected difference is a non-positive number, thus obtaining the first difference.

[0060] Specifically, the difference = first average - second average (e.g., ΔV = Vdc) mean -Vdc Fill ).

[0061] If the difference is positive (e.g., a sudden increase in bus voltage, ΔV>0), the difference needs to be corrected and assigned a value of 0, resulting in a first difference of 0. If the difference is negative (e.g., a sudden decrease in bus voltage, ΔV<0), the original value is retained, so that the final first difference is non-positive.

[0062] The purpose of this numerical correction is to ensure that when a significant drop in bus voltage occurs, the average value Vdc... mean The rate of decline will be faster and less than Vdc Fill At this point, ΔV is negative, and the output after PI calculation is also negative. Conversely, if the bus voltage rises significantly, ΔV is greater than 0, and it is assigned the value of 0 to ensure that the input and output value of PI calculation are not positive, thus avoiding an increase in motor speed and incorrect frequency boosting.

[0063] In this embodiment of the disclosure, the first difference is always non-positive by numerical limitation, thus avoiding the situation of motor frequency erroneous increase under interference conditions from the data source.

[0064] This disclosure provides a method for controlling the frequency reduction of a motor, which can be used in the controller of an electrical appliance. Figure 4 This is a flowchart illustrating another motor frequency reduction control method according to an embodiment of the present disclosure, as shown below. Figure 4 As shown, the process includes the following steps: Step S401: Obtain real-time operating data of the motor. For details, please refer to [link / reference]. Figure 2 Step S201 of the illustrated embodiment will not be described again here.

[0065] Step S402: Based on real-time operating data, obtain the first reduced-frequency speed and the second reduced-frequency speed, where the first reduced-frequency speed represents the motor speed in the first cycle, and the second reduced-frequency speed represents the motor speed in the second cycle. For details, please refer to [link to relevant documentation]. Figure 2 Step S202 of the illustrated embodiment will not be described again here.

[0066] Step S403: Adjust the first frequency reduction speed according to the difference between the first frequency reduction speed and the second frequency reduction speed to obtain the third frequency reduction speed.

[0067] Specifically, step S403 includes: Step S4031: Obtain the second difference between the first reduced-frequency speed and the second reduced-frequency speed; Step S4032: Compare the second difference with the upper limit of the rate of change of the speed difference to obtain the first comparison result; Step S4033: Adjust the first frequency reduction speed based on the first comparison result, and determine the third frequency reduction speed.

[0068] Specifically, the second difference is Δω = ω0 (first frequency reduction speed) - ω pre (Second frequency reduction speed) quantifies the change amplitude of frequency reduction speed between two adjacent cycles through the second difference.

[0069] Define the upper limit of the rate of change of rotational speed difference as Δω thrThe value ranges from 0.05 to 0.15 Hz / ms. The second difference Δω is compared with the upper limit of the rate of change of the speed difference Δω. thr The comparison is performed to obtain the first comparison result. At this point, the first comparison result falls into two categories: Δω > Δω. thr , △ω<-△ω thr .

[0070] Among them, setting a limit on the rate of change of parameters in motor control (i.e., setting an upper limit for the rate of change of speed difference) is a means to avoid sudden changes in control quantity. It can prevent problems such as stalling, overcurrent, and mechanical shock caused by sudden changes in control quantity, and is a necessary measure to ensure the smooth operation of motor.

[0071] Based on the first comparison result above, the first frequency reduction speed ω0 is adjusted by limiting, and the adjusted result is the third frequency reduction speed.

[0072] Step S404: Based on the third reduced-frequency speed, frequency reduction control is performed on the motor during the first cycle. For details, please refer to [link to relevant documentation]. Figure 2 Step S204 of the illustrated embodiment will not be described again here.

[0073] In this embodiment of the disclosure, the second difference is compared with the upper limit of the rate of change of the speed difference to achieve a quantitative judgment of the rate of change of the reduced speed, clarify the adjustment threshold of the reduced speed, make the speed adjustment follow a set pattern, avoid subjective adjustment judgment, and improve the scientific nature of the adjustment process.

[0074] As an optional embodiment, step S4033 includes: Step b1: If the first comparison result indicates that the second difference is greater than the upper limit of the rate of change of the speed difference, then based on the second frequency reduction speed and the upper limit of the rate of change of the speed difference, the first frequency reduction speed is adjusted to determine the third frequency reduction speed. Step b2: If the first comparison result indicates that the second difference is less than the negative of the upper limit of the speed difference change rate, then the first speed reduction speed is adjusted based on the negative of the second speed reduction speed and the upper limit of the speed difference change rate to determine the third speed reduction speed.

[0075] Specifically, when △ω>△ω thr This indicates that the frequency reduction amplitude of the current frequency reduction speed is decreasing rapidly. If not limited, it will lead to insufficient frequency reduction and ineffective interference suppression. By adjusting the rule to ω0=ω pre +△ω thr This means limiting the first frequency reduction speed to "the speed of the previous cycle + the upper limit value" to prevent the frequency reduction speed from increasing too quickly. This adjustment rule limits the rate of decrease in the frequency reduction amplitude to Δω. thr Internally, this ensures the effectiveness of frequency reduction.

[0076] When Δω < -Δω thrThis indicates that the frequency reduction rate is rapidly increasing. If left unchecked, it will cause a sudden drop in motor speed, leading to mechanical shock and electrical faults. Adjusting the rule to ω0=ω pre -△ω thr This means limiting the first frequency reduction speed to "the previous cycle speed - the upper limit value" to prevent the frequency reduction speed from decreasing too quickly. This adjustment rule limits the rate of increase in the frequency reduction amplitude to Δω. thr Internally, this ensures the stability of frequency reduction.

[0077] In other cases, keep ω0 unchanged.

[0078] As shown above, the adjusted ω0 is obtained, and the adjusted ω0 is assigned to ω. pre , assign the value ω pre Use it in the next cycle.

[0079] The third frequency reduction speed is then obtained based on the adjusted ω0.

[0080] In this embodiment of the disclosure, by comparing the second difference with the upper limit of the rate of change of the speed difference, and setting different first frequency reduction speed adjustment rules according to the comparison result, the frequency reduction speed is restricted from rising too quickly (frequency reduction amplitude decreases) and also restricted from falling too quickly (frequency reduction amplitude increases), so as to achieve precise control of the frequency reduction speed across the entire range.

[0081] As an optional embodiment, adjusting the first reduced-frequency speed in step b1 or step b2 to determine the third reduced-frequency speed includes: Step c1: Adjust the first frequency reduction speed to obtain the adjusted first frequency reduction speed; Step c2: Compare the adjusted first frequency reduction speed with the first speed threshold to obtain the second comparison result; compare the adjusted first frequency reduction speed with the second speed threshold to obtain the third comparison result. Step c3: Based on the second and third comparison results, the third frequency reduction speed is obtained.

[0082] Specifically, in this embodiment of the disclosure, dual thresholds are set in the motor control to limit the control quantity within a reasonable execution range and avoid exceeding the physical operating limits of the motor.

[0083] Furthermore, an upper limit is set for the rate of change of the speed difference Δω: the first speed threshold is ω. high (Values ​​can range from -20 to -10 Hz), set the minimum value of the final feedforward to the speed loop: the second speed threshold is ω. low (Values ​​can range from -50 to -100 Hz).

[0084] The adjusted first frequency reduction speed ω0 can be obtained from the adjustment rules of the above embodiments. The adjusted first frequency reduction speed ω0 is then compared with the first speed threshold ω. high A comparison is made to obtain a second comparison result, and the adjusted first frequency reduction speed ω0 is compared with the second speed threshold ω. low By comparing the results, we obtain the third comparison result.

[0085] If the second comparison result is: the adjusted first frequency reduction speed ω0 is greater than the first speed threshold ω high If the third frequency reduction speed ω1 is assigned a preset value, such as 0, i.e., the third frequency reduction speed ω1 = 0, the motor will not perform frequency reduction. If the third comparison result is: the adjusted first frequency reduction speed ω0 is less than the second speed threshold ω low Then the third frequency reduction speed ω1 is assigned the value of the second speed threshold ω. low That is, the third frequency reduction speed ω1=ω low This limits the reduced-frequency rotational speed to a minimum. Other cases, i.e., ω... low ≤ω0≤ω high The third frequency reduction speed ω1 is assigned the adjusted first frequency reduction speed ω0, i.e., ω1=ω0, and the first frequency reduction speed after the rate of change is directly adopted.

[0086] In this embodiment, a first speed threshold and a second speed threshold are used to perform a bidirectional comparison and judgment on the adjusted first frequency reduction speed. Based on the comparison result, a specific value of the third frequency reduction speed is set to limit the range of the third frequency reduction speed, so that the third frequency reduction speed is always within the range of the physical operating limit of the motor and the control requirement limit, thus avoiding the output of ineffective control quantities.

[0087] As an optional embodiment, the real-time operating data includes at least one of bus voltage data, preset axial current data, and mechanical power data. That is, any one of the bus voltage data, preset axial current data, and mechanical power data can be used as the real-time operating data obtained at the moment, or they can be used together as the real-time operating data obtained at the moment, or all three data can be used together as the real-time operating data obtained at the moment.

[0088] If the real-time operating data is bus voltage data, then... Figure 5 , and by Figure 5 The dashed box portion is used to calculate the average value of the motor bus voltage (Vdc). mean ) and the value after filtering the average (Vdc) Fill This allows the system to quickly reduce the motor speed when the bus voltage rises significantly, by feeding the PI calculation results forward to the motor speed loop control.

[0089] If the real-time operating data is the preset axial current data (such as q-axis current), then the corresponding Figure 6 ,use Figure 6 replace Figure 5 Within the dashed box section, calculate the average value of the motor's q-axis current (Iq). mean ) and the value after filtering the average (Iq) Fill This allows the PI calculation results to be fed forward into the motor speed loop control when the q-axis current rises sharply, thereby quickly reducing the motor speed.

[0090] If the real-time operating data is mechanical power data, then... Figure 7 ,use Figure 7 replace Figure 5 The dashed box section is used to calculate the average value of the motor's mechanical power (Pmech). mean ) and the value after filtering the average (Pmech) Fill This allows for rapid reduction of motor speed when mechanical power increases significantly. The PI calculation result is fed forward into the motor speed loop control. Specifically, the formula for calculating motor mechanical power is Pmech = motor torque × actual motor speed.

[0091] By making these three factors optional, the method can be adapted to different application scenarios (such as air conditioner compressors focusing more on bus voltage and q-axis current, and washing machine motors focusing more on mechanical power), thus improving the versatility of the method.

[0092] As an optional embodiment, the real-time operating data includes at least two of the following: bus voltage data, preset axial current data, and mechanical power data.

[0093] Specifically, a single operational data point can only reflect one type of interference (e.g., bus voltage only reflects grid interference), while motors are often subjected to complex interference in actual operation (e.g., a sudden drop in grid voltage + a sudden increase in load). Collecting at least two types of data can achieve multi-dimensional interference identification, improve the comprehensiveness and accuracy of anti-interference, and avoid missing interference due to a single data point.

[0094] If the collected real-time operating data is at least two of the following: bus voltage data, preset axial current data, and mechanical power data, then for each type of real-time operating data, the complete steps of S201-S204 of the above embodiment are executed to obtain their respective third frequency reduction speeds. The obtained multiple third frequency reduction speeds are numerically fused. For example, weights are assigned according to the importance of the parameters, and a weighted average is calculated to obtain the final unique third frequency reduction speed (i.e., the fused value). Alternatively, the minimum value among the multiple third frequency reduction speeds can be taken as the final unique third frequency reduction speed, which can achieve the most conservative frequency reduction control, such as the best anti-interference capability. The maximum value among the multiple third frequency reduction speeds can also be taken as the final unique third frequency reduction speed, which can achieve the gentlest frequency reduction control.

[0095] As an optional embodiment, the method further includes: Step d1: Obtain the target motor speed; Step d2: Add the third reduced-frequency speed to the target motor speed to obtain the adjusted motor speed; Step d3: Use the adjusted motor speed in the double closed-loop control of the field-oriented control to obtain the actual motor speed.

[0096] Specifically, after obtaining the third reduced-frequency speed from the above embodiments, since the third reduced-frequency speed ω1 here is a calculated "theoretical value" that does not take into account individual differences of the motor (such as motor aging, manufacturing errors) and real-time operating status (such as load fluctuations not being fully detected), if the motor is driven directly according to the adjusted third reduced-frequency speed, the actual speed may deviate greatly from the target speed. Therefore, it is necessary to superimpose it on the speed loop control and execute the dual closed-loop control of the motor FOC to obtain the actual speed of the motor.

[0097] refer to Figure 5 The specific process is as follows: Users can set the operating mode and speed setting (such as 16℃ / 26℃ for air conditioners, quick wash / large item wash for washing machines, and 2℃ / -18℃ for refrigerators) through the control panel, remote control, or APP of the home appliance. The appliance controller will directly retrieve the corresponding motor target speed according to the preset speed setting and speed mapping table. .

[0098] Connect ω1 with The adjusted motor speed is obtained by superimposing the results.

[0099] Entering the FOC speed loop: The speed loop calculates the deviation between the "adjusted target speed" and the "actual motor speed ω", and outputs the d-axis command current i. d q-axis command current i q Current loop comparison i d i q With the actual current i on the d-axis d and the actual q-axis current i q The deviation is adjusted by PI control of the output d-axis command voltage u. d q-axis command voltage u q Among these methods, measurable signals such as the motor's voltage and current are input into the speed observer to estimate the motor's "actual speed ω". d i q It is obtained by current sampling and coordinate transformation: by sampling the three-phase current of the motor (i a i b i cAfter Clark transformation → Park transformation, the actual d-axis current i is obtained. d and the actual q-axis current i q .

[0100] will u d u q After inverse Park transform → inverse Clark transform, and then SVPWM (Space Vector Pulse Width Modulation) to generate three-phase voltage commands, the position and amplitude of the space voltage vector are calculated based on the three-phase voltage commands, ultimately generating the on / off timing sequence. After receiving the SVPWM on / off timing signal, the frequency converter drive rapidly turns the IGBT (Insulated-Gate Bipolar Transistor) on / off according to the command. Through the switching action of the IGBT, the voltage is inverted into three-phase AC power with controllable amplitude and frequency. The stator windings of the permanent magnet synchronous motor receive the three-phase AC power output from the frequency converter drive, generating a rotating magnetic field (the magnetic field speed is proportional to the AC frequency). The permanent magnets of the rotor are driven to rotate under the action of the rotating magnetic field, converting electrical energy into mechanical energy, ultimately obtaining the actual speed of the motor.

[0101] As an alternative embodiment, such as Figure 8 As shown, Figure 8 This is a complete flowchart of the motor frequency reduction control method according to an embodiment of the present disclosure. The specific process is as follows: Collect real-time operating data; taking the bus voltage as an example, the following process will be explained.

[0102] Calculate the average bus voltage Vdc mean .

[0103] For Vdc mean Vdc is obtained after low-pass filtering. Fill .

[0104] Calculate Vdc mean and Vdc Fill The difference ΔV is calculated. If ΔV > 0, then ΔV is assigned the value 0; otherwise, ΔV is input into the PI controller for calculation.

[0105] The PI calculation outputs the reduced-frequency rotational speed ω0.

[0106] Calculate the frequency reduction speed ω0 of the current cycle and the frequency reduction speed ω of the previous cycle. pre The difference is Δω.

[0107] If △ω>△ω thr The current calculated output frequency reduction speed ω0=ω pre +△ω thr If Δω < -Δωthr The current calculated output frequency reduction speed ω0=ω pre -△ω thr And assign the adjusted ω0 value to ω. pre , assign the value ω pre Use it in the next cycle.

[0108] If ω0>ω high If ω1 = 0, then ω0 < ω low Then ω1=ω low Otherwise (ω) low ≤ω0≤ω high ω1=ω0.

[0109] ω1 is added to the speed loop control to achieve feedforward control, and then the motor FOC control is applied.

[0110] Figure 8 The dashed box section can be replaced with the average value of the motor's q-axis current and the filtered value obtained after filtering; it can also be replaced with the average value of the motor's mechanical power and the filtered value obtained after filtering. The subsequent calculation process is the same as that for bus voltage, and will not be repeated here.

[0111] This embodiment also provides a motor frequency reduction control device, which is used to implement the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0112] This embodiment provides a motor frequency reduction control device, such as... Figure 9 As shown, it includes: The first acquisition module 901 is used to acquire real-time operating data of the motor; The first obtaining module 902 is used to obtain the first reduced frequency speed and the second reduced frequency speed based on real-time operating data, wherein the first reduced frequency speed represents the motor speed in the first cycle and the second reduced frequency speed represents the motor speed in the second cycle. The adjustment module 903 is used to adjust the first frequency reduction speed according to the difference between the first frequency reduction speed and the second frequency reduction speed to obtain the third frequency reduction speed; The frequency reduction module 904 is used to reduce the frequency of the motor in the first cycle based on the third frequency reduction speed.

[0113] In this embodiment, by acquiring real-time operating data of the motor, a first reduced-frequency speed and a second reduced-frequency speed are obtained based on the real-time operating data. Then, based on the difference between the first and second reduced-frequency speeds, the first reduced-frequency speed is adjusted to obtain a third reduced-frequency speed. Finally, based on the third reduced-frequency speed, the motor is frequency-reduced within the first cycle. In this way, when extreme situations such as sudden changes in bus voltage, motor current, or load occur, the pre-calculated third reduced-frequency speed for motor frequency reduction is superimposed on the subsequent motor speed to achieve feedforward control of motor frequency reduction. Based on this feedforward control, the compressor frequency can be rapidly reduced, avoiding motor faults such as overcurrent, overvoltage, and stall, reducing machine downtime and maintenance.

[0114] In some alternative implementations, the first receiving module 902 includes: The determination submodule is used to determine the reduced-frequency rotation speed under multiple cycles based on real-time operating data; The selection submodule is used to select the first and second frequency reduction speeds from the frequency reduction speeds.

[0115] In some alternative implementations, a submodule is defined, including: The first acquisition unit is used to acquire the first average value of real-time running data over multiple periods; The filtering unit is used to filter the first average value to obtain the second average value. The second acquisition unit is used to acquire a first difference between the first average value and the second average value; The processing unit is used to process the first difference based on the proportional-integral controller to obtain the reduced-frequency speed of the motor in multiple cycles.

[0116] In some optional implementations, the second acquisition unit includes: The sub-unit for calculating the difference is used to calculate the difference between the first average and the second average. The correction subunit is used to numerically correct the difference so that the corrected difference is a non-positive number, thus obtaining the first difference.

[0117] In some alternative implementations, the adjustment module 903 includes: The acquisition submodule is used to acquire the second difference between the first frequency reduction speed and the second frequency reduction speed; The comparison submodule is used to compare the second difference with the upper limit of the rate of change of the speed difference to obtain the first comparison result; The adjustment submodule is used to adjust the first frequency reduction speed based on the first comparison result and determine the third frequency reduction speed.

[0118] In some alternative implementations, the submodule is adjusted, including: The first adjustment unit is used to adjust the first frequency reduction speed based on the second frequency reduction speed and the upper limit of the speed difference change rate if the first comparison result indicates that the second difference is greater than the upper limit of the speed difference change rate, and to determine the third frequency reduction speed. The second adjustment unit is used to adjust the first frequency reduction speed and determine the third frequency reduction speed based on the opposite number of the second frequency reduction speed and the upper limit of the speed difference change rate if the first comparison result indicates that the second difference is less than the opposite number of the upper limit of the speed difference change rate.

[0119] In some optional implementations, the first adjustment unit or the second adjustment unit includes: The first subunit is used to adjust the first frequency reduction speed to obtain the adjusted first frequency reduction speed. The comparison subunit is used to compare the adjusted first frequency reduction speed with the first speed threshold to obtain a second comparison result, and to compare the adjusted first frequency reduction speed with the second speed threshold to obtain a third comparison result; The second sub-unit is used to obtain the third frequency reduction speed based on the second comparison result and the third comparison result.

[0120] In some optional embodiments, the second obtaining subunit is configured to: if the second comparison result indicates that the adjusted first frequency reduction speed is greater than the first speed threshold, then assign the third frequency reduction speed to a preset value; if the third comparison result indicates that the adjusted first frequency reduction speed is less than the second speed threshold, then assign the third frequency reduction speed to the second speed threshold; if the second comparison result indicates that the adjusted first frequency reduction speed is less than or equal to the first speed threshold, and the third comparison result indicates that the adjusted first frequency reduction speed is greater than or equal to the second speed threshold, then assign the third frequency reduction speed to the adjusted first frequency reduction speed.

[0121] In some alternative implementations, the real-time operating data includes at least one of bus voltage data, preset axial current data, and mechanical power data.

[0122] In some alternative implementations, the real-time operating data includes at least two of the following: bus voltage data, preset axial current data, and mechanical power data.

[0123] In some optional implementations, when the real-time operating data includes at least two of the following: bus voltage data, preset axial current data, and mechanical power data, the adjustment module 903 includes: The submodule is used to obtain the corresponding third frequency reduction speed based on each real-time running data; The fusion submodule is used to perform numerical fusion on the third reduced-frequency speed to obtain the fused third reduced-frequency speed.

[0124] In some alternative embodiments, the device further includes: The second acquisition module is used to acquire the target speed of the motor; The superposition module is used to superimpose the third reduced-frequency speed with the target motor speed to obtain the adjusted motor speed; The second module is used to obtain the actual motor speed by using the adjusted motor speed in the dual closed-loop control of the field-oriented control.

[0125] Further functional descriptions of the above modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0126] In this embodiment, the motor frequency reduction control device is presented in the form of a functional unit. Here, a unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that execute one or more software or fixed programs, and / or other devices that can provide the above functions.

[0127] Figure 10 This is a schematic diagram of the structure of a controller for an electrical device provided in an embodiment of this disclosure.

[0128] The following is a detailed reference. Figure 10 The diagram illustrates a structural schematic suitable for implementing a controller according to embodiments of the present disclosure. The controller may include a processor (e.g., a central processing unit, graphics processing unit, etc.) 1001, which can perform various appropriate actions and processes based on a program stored in read-only memory (ROM) 1002 or a program loaded from memory 1008 into random access memory (RAM) 1003. The RAM 1003 also stores various programs and data required for controller operation. The processor 1001, ROM 1002, and RAM 1003 are interconnected via a bus 1004. An input / output (I / O) interface 1005 is also connected to the bus 1004.

[0129] Typically, the following devices can be connected to the I / O interface 1005: input devices 1006 including, for example, a touchscreen, touchpad, keyboard, mouse, camera, microphone, accelerometer, gyroscope, etc.; output devices 1007 including, for example, a liquid crystal display (LCD), speaker, vibrator, etc.; memory 1008 including, for example, magnetic tape, hard disk, etc.; and communication devices 1009. Communication device 1009 allows the controller to communicate wirelessly or wiredly with other devices to exchange data. Although Figure 10 A controller with various devices is shown, but it should be understood that it is not required to implement or have all of the devices shown, and may alternatively implement or have more or fewer devices.

[0130] In particular, according to embodiments of this disclosure, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of this disclosure include a computer program product comprising a computer program carried on a non-transitory computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device 1009, or installed from a memory 1008, or installed from a ROM 1002. When the computer program is executed by the processor 1001, it performs the functions defined in the water replenishment control method for a drinking water device according to embodiments of this disclosure.

[0131] Figure 10 The controller shown is merely an example and should not be construed as limiting the functionality and scope of use of the embodiments disclosed herein.

[0132] This disclosure also provides a computer-readable storage medium in which the methods described in this disclosure can be implemented in hardware or firmware, or implemented as computer code that can be recorded on a storage medium, or implemented as computer code downloaded over a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and then stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that the computer, processor, microprocessor controller, or programmable hardware includes storage components capable of storing or receiving software or computer code. When the software or computer code is accessed and executed by the computer, processor, or hardware, the water replenishment control method for the drinking water device shown in the above embodiments is implemented.

[0133] A portion of this disclosure can be applied to computer program products, such as computer program instructions, which, when executed by a computer, can invoke or provide methods and / or technical solutions according to this disclosure through the operation of the computer. Those skilled in the art will understand that the forms in which computer program instructions exist in a computer-readable medium include, but are not limited to, source files, executable files, and installation package files. Accordingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executing the instructions; the computer compiling the instructions and then executing the corresponding compiled program; the computer reading and executing the instructions; or the computer reading and installing the instructions and then executing the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to a computer.

[0134] Although embodiments of the present disclosure have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present disclosure, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for controlling the frequency reduction of a motor, characterized in that, The method includes: Obtain real-time operating data of the motor; Based on the real-time operating data, a first reduced-frequency speed and a second reduced-frequency speed are obtained, wherein the first reduced-frequency speed represents the motor speed in the first cycle, and the second reduced-frequency speed represents the motor speed in the second cycle; Based on the difference between the first frequency reduction speed and the second frequency reduction speed, the first frequency reduction speed is adjusted to obtain the third frequency reduction speed; Based on the third reduced-frequency speed, the motor is controlled to reduce frequency during the first cycle.

2. The method according to claim 1, characterized in that, The process of obtaining the first reduced-frequency speed and the second reduced-frequency speed based on the real-time operating data includes: Based on the real-time operating data, the reduced-frequency rotation speed is determined under multiple cycles; Select the first frequency reduction speed and the second frequency reduction speed from the frequency reduction speeds.

3. The method according to claim 2, characterized in that, The determination of the reduced-frequency rotation speed under multiple cycles based on the real-time operating data includes: Obtain the first average value of the real-time operating data over multiple periods; The first average value is filtered to obtain the second average value; Obtain the first difference between the first average value and the second average value; The first difference is processed by a proportional-integral controller to obtain the reduced-frequency speed of the motor in multiple cycles.

4. The method according to claim 3, characterized in that, Obtaining the first difference between the first average and the second average includes: The difference is obtained by subtracting the first average value from the second average value. The difference is numerically corrected so that the corrected difference is a non-positive number, thus obtaining the first difference.

5. The method according to claim 1, characterized in that, The step of adjusting the first frequency reduction speed based on the difference between the first and second frequency reduction speeds to obtain a third frequency reduction speed includes: Obtain the second difference between the first frequency reduction speed and the second frequency reduction speed; The second difference is compared with the upper limit of the rate of change of the speed difference to obtain the first comparison result; Based on the first comparison result, the first frequency reduction speed is adjusted to determine the third frequency reduction speed.

6. The method according to claim 5, characterized in that, The step of adjusting the first frequency reduction speed based on the first comparison result and determining the third frequency reduction speed includes: If the first comparison result indicates that the second difference is greater than the upper limit of the rate of change of the speed difference, then based on the second reduced-frequency speed and the upper limit of the rate of change of the speed difference, the first reduced-frequency speed is adjusted to determine the third reduced-frequency speed. If the first comparison result indicates that the second difference is less than the negative of the upper limit of the rate of change of the speed difference, then the first rate of change is adjusted based on the negative of the second rate of change and the upper limit of the rate of change of the speed difference, and the third rate of change is determined.

7. The method according to claim 6, characterized in that, The step of adjusting the first frequency reduction speed and determining the third frequency reduction speed includes: Adjust the first frequency reduction speed to obtain the adjusted first frequency reduction speed; The adjusted first frequency reduction speed is compared with the first speed threshold to obtain a second comparison result, and the adjusted first frequency reduction speed is compared with the second speed threshold to obtain a third comparison result; Based on the second comparison result and the third comparison result, the third frequency reduction speed is obtained.

8. The method according to claim 7, characterized in that, The process of obtaining the third reduced-frequency rotational speed based on the second comparison result and the third comparison result includes: If the second comparison result indicates that the adjusted first frequency reduction speed is greater than the first speed threshold, then the third frequency reduction speed is assigned a preset value; If the third comparison result indicates that the adjusted first frequency reduction speed is less than the second speed threshold, then the third frequency reduction speed is assigned the value of the second speed threshold. If the second comparison result indicates that the adjusted first frequency reduction speed is less than or equal to the first speed threshold, and the third comparison result indicates that the adjusted first frequency reduction speed is greater than or equal to the second speed threshold, then the third frequency reduction speed is assigned the value of the adjusted first frequency reduction speed.

9. The method according to claim 1, characterized in that, The real-time operating data includes at least one of the following: bus voltage data, preset axial current data, and mechanical power data.

10. The method according to claim 9, characterized in that, The real-time operating data includes at least two of the following: the bus voltage data, the preset axial current data, and the mechanical power data.

11. The method according to claim 10, characterized in that, When the real-time operating data includes at least two of the bus voltage data, the preset axial current data, and the mechanical power data, obtaining the third frequency-reduced speed includes: Based on each of the aforementioned real-time operating data, the corresponding third frequency reduction speed is obtained; The third frequency-reduced speed is numerically fused to obtain the fused third frequency-reduced speed.

12. The method according to claim 1, characterized in that, The method further includes: Obtain the target motor speed; The third frequency-reduced speed is superimposed on the target speed of the motor to obtain the adjusted motor speed; The adjusted motor speed is used in the dual closed-loop control of the field-oriented control to obtain the actual motor speed.

13. A motor frequency reduction control device, characterized in that, The device includes: The first acquisition module is used to acquire the real-time operating data of the motor; The first obtaining module is used to obtain a first reduced frequency speed and a second reduced frequency speed based on the real-time operating data, wherein the first reduced frequency speed represents the motor speed in the first cycle and the second reduced frequency speed represents the motor speed in the second cycle. An adjustment module is used to adjust the first frequency reduction speed according to the difference between the first frequency reduction speed and the second frequency reduction speed to obtain a third frequency reduction speed; The frequency reduction module is used to control the motor to reduce its frequency within the first cycle based on the third frequency reduction speed.

14. An electrical appliance, characterized in that, The electrical device includes a motor and a controller. The controller includes a memory and a processor, which are communicatively connected. The memory stores computer instructions, and the processor executes the computer instructions to perform the motor frequency reduction control method according to any one of claims 1 to 12, for controlling the motor.

15. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing the computer to execute the motor frequency reduction control method according to any one of claims 1 to 12.

16. A computer program product, characterized in that, Includes computer instructions, which are used to cause a computer to execute the motor frequency reduction control method according to any one of claims 1 to 12.

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