Household appliance and control method thereof

Abstract

The invention provides a household appliance and a control method thereof.The household appliance comprises a shell, an asynchronous motor and a controller, and the asynchronous motor is arranged in the shell and used for operating according to alternating current input voltage; a controller configured to: generate a harmonic voltage of the AC input voltage; superposing the harmonic voltage to the AC input voltage to serve as the input voltage of the asynchronous motor, and increasing or decreasing the amplitude of the harmonic voltage according to a preset step length to adjust the amplitude of the harmonic voltage; in the process of adjusting the amplitude of the harmonic voltage, collecting vibration signals generated by the asynchronous motor under different amplitudes of the harmonic voltage; and determining whether to stop adjusting the amplitude of the harmonic voltage according to the amplitude of the vibration signal and a preset harmonic voltage amplitude range so as to reduce the amplitude of the vibration signal. According to the invention, the amplitude of the vibration signal is reduced by adjusting the amplitude of the harmonic voltage input into the asynchronous motor, so that the vibration reduction effect is improved, the noise of household equipment is reduced, and the performance of the household equipment is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of household electrical appliances, and in particular to a household electrical appliance and a control method thereof. Background Art

[0002] In daily life, asynchronous motors are widely used in household appliances. In the field of air conditioning, they are widely used in fan systems and fresh air systems of various indoor units such as duct units, embedded units, cabinet units, and fan disc units; in addition, they are also used in outdoor units with side and top air outlets, dehumidifiers, window units, and other integrated units as well as compressors.

[0003] At present, when asynchronous motors are working, the vibration of asynchronous motors excites other related structures to generate secondary noise, which is one of the main problems in the application process and has a great impact on the actual user experience. The double power frequency vibration is one of the main vibration components of asynchronous motors. Due to its relatively high amplitude and low frequency (100Hz or 120Hz), the noise generated is difficult to be treated by conventional noise reduction solutions such as sound absorption and sound insulation. It brings great annoyance to users and is one of the main reasons for noise complaints in the market. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0005] To this end, an object of the present invention is to provide a household appliance, which adjusts the amplitude of the harmonic voltage input to the asynchronous motor to reduce the amplitude of the vibration signal, thereby improving the vibration reduction effect, reducing the noise of the household appliance, and further improving the performance of the household appliance.

[0006] Therefore, a second object of the present invention is to provide a control method for a household appliance.

[0007] In order to achieve the above-mentioned purpose, an embodiment of the first aspect of the present invention proposes a household appliance, which includes: a housing; an asynchronous motor, which is arranged in the housing and is used to operate according to an AC input voltage; a controller, which is configured to: generate a harmonic voltage of the AC input voltage; after superimposing the harmonic voltage on the AC input voltage, use it as the input voltage of the asynchronous motor, and increase or decrease the amplitude of the harmonic voltage according to a preset step size to adjust the amplitude of the harmonic voltage; in the process of adjusting the amplitude of the harmonic voltage, collect vibration signals generated by the asynchronous motor under different amplitudes of the harmonic voltage; determine whether to stop adjusting the amplitude of the harmonic voltage according to the amplitude of the vibration signal and a preset harmonic voltage amplitude range to reduce the amplitude of the vibration signal.

[0008] According to the household appliance of the embodiment of the present invention, the harmonic voltage of the AC input voltage is superimposed on the AC input voltage as the input voltage of the asynchronous motor, and then the amplitude of the harmonic voltage is increased or decreased according to a preset step size to adjust the amplitude of the harmonic voltage. In the process of adjusting the amplitude of the harmonic voltage, the vibration signal generated by the asynchronous motor under different amplitudes of the harmonic voltage is collected; according to the amplitude of the vibration signal and the preset harmonic voltage amplitude range, it is determined whether to stop adjusting the amplitude of the harmonic voltage to reduce the amplitude of the vibration signal, thereby improving the vibration reduction effect, reducing the noise of the household appliance, and then improving the performance of the household appliance.

[0009] In some embodiments, whether to stop adjusting the amplitude of the harmonic voltage is determined according to the amplitude of the vibration signal and a preset harmonic voltage amplitude range, and the controller is specifically configured as follows: when increasing the amplitude of the harmonic voltage according to a preset step size, judging whether the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage reaches the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage; when judging that the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage does not reach the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, continuing to increase the amplitude of the harmonic voltage according to the preset step size until the amplitude of the vibration signal reaches a first minimum value; or , when the amplitude of the vibration signal does not reach the first minimum value, and the amplitude of the current harmonic voltage reaches the upper limit value of the preset harmonic voltage amplitude range, stop adjusting the amplitude of the harmonic voltage; when it is judged that the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage reaches the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, reduce the amplitude of the harmonic voltage according to a preset step size until the amplitude of the vibration signal reaches the second minimum value; or, when the amplitude of the vibration signal does not reach the second minimum value, and the amplitude of the current harmonic voltage reaches the lower limit value of the preset harmonic voltage amplitude range, stop adjusting the amplitude of the harmonic voltage.

[0010] In some embodiments, whether to stop adjusting the amplitude of the harmonic voltage is determined according to the amplitude of the vibration signal and a preset harmonic voltage amplitude range, and the controller is specifically configured as follows: when reducing the amplitude of the harmonic voltage according to a preset step size, judging whether the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage reaches the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage; when judging that the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage does not reach the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, continuing to reduce the amplitude of the harmonic voltage according to the preset step size until the amplitude of the vibration signal reaches a third minimum value; or , when the amplitude of the vibration signal does not reach the third minimum value, and the amplitude of the current harmonic voltage reaches the lower limit value of the preset harmonic voltage amplitude range, stop adjusting the amplitude of the harmonic voltage; when it is judged that the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage reaches the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, increase the amplitude of the harmonic voltage according to a preset step size until the amplitude of the vibration signal reaches a fourth minimum value; or, when the amplitude of the vibration signal does not reach the fourth minimum value, and the amplitude of the current harmonic voltage reaches the upper limit value of the preset harmonic voltage amplitude range, stop adjusting the amplitude of the harmonic voltage.

[0011] In some embodiments, after stopping adjusting the amplitude of the harmonic voltage, the controller is further configured to: obtain the current change amplitude of the asynchronous motor; and determine whether to repeat the step of increasing or decreasing the amplitude of the harmonic voltage according to a preset step size based on the current change amplitude.

[0012] In some embodiments, whether to repeat the step of increasing or decreasing the amplitude of the harmonic voltage according to a preset step length is determined according to the current change amplitude, and the controller is specifically configured to: when the current change amplitude does not reach the preset current change amplitude, not perform the step of increasing or decreasing the amplitude of the harmonic voltage according to the preset step length. When the current change amplitude reaches the preset current change amplitude, repeat the step of increasing or decreasing the amplitude of the harmonic voltage according to the preset step length.

[0013] In some embodiments, when determining the amplitude of the vibration signal, the controller is specifically configured to: perform Fourier transform on the vibration signal according to a preset frequency step; determine, based on the Fourier transform result, a first amplitude corresponding to a vibration signal with a frequency twice the frequency of the AC input voltage, and a second amplitude corresponding to a vibration signal with a frequency four times the frequency of the AC input voltage; and determine the amplitude of the vibration signal based on the first amplitude and the second amplitude.

[0014] In some embodiments, when determining the amplitude of the vibration signal according to the first amplitude and the second amplitude, the controller is specifically configured to: calculate the root mean square of the first amplitude and the second amplitude; and use the root mean square as the amplitude of the vibration signal.

[0015] In some embodiments, before performing Fourier transform on the vibration signal according to the preset frequency step, the controller is further configured to: determine the preset frequency step according to the speed fluctuation range of the asynchronous motor.

[0016] In some embodiments, when the preset frequency step is determined according to the speed fluctuation range of the asynchronous motor, the controller is specifically configured as follows:

[0017] Δf>(2*ΔV) / 60*2;

[0018] Wherein, Δf is the preset frequency step, and ΔV is the speed fluctuation range of the asynchronous motor.

[0019] In order to achieve the above-mentioned purpose, an embodiment of the second aspect of the present invention proposes a control method for household appliances, the method comprising: generating a harmonic voltage of an AC input voltage; superimposing the harmonic voltage on the AC input voltage as the input voltage of an asynchronous motor, and increasing or decreasing the amplitude of the harmonic voltage according to a preset step size to adjust the amplitude of the harmonic voltage; in the process of adjusting the amplitude of the harmonic voltage, collecting a vibration signal generated by the asynchronous motor under different amplitudes of the harmonic voltage; determining whether to stop adjusting the amplitude of the harmonic voltage according to the amplitude of the vibration signal and a preset harmonic voltage amplitude range to reduce the amplitude of the vibration signal.

[0020] According to the control method of the household appliance of the embodiment of the present invention, the harmonic voltage of the AC input voltage is superimposed on the AC input voltage as the input voltage of the asynchronous motor, and then the amplitude of the harmonic voltage is increased or decreased according to a preset step size to adjust the amplitude of the harmonic voltage. In the process of adjusting the amplitude of the harmonic voltage, the vibration signal generated by the asynchronous motor under different amplitudes of the harmonic voltage is collected; according to the amplitude of the vibration signal and the preset harmonic voltage amplitude range, it is determined whether to stop adjusting the amplitude of the harmonic voltage to reduce the amplitude of the vibration signal, thereby improving the vibration reduction effect, reducing the noise of the household appliance, and further improving the performance of the household appliance.

[0021] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0023] Figure 1 is a structural block diagram of a household appliance according to an embodiment of the present invention;

[0024] Figure 2 is a schematic diagram of a control flow of an asynchronous motor of a household appliance according to an embodiment of the present invention;

[0025] Figure 3 is a schematic diagram of a control flow of an asynchronous motor of a household appliance according to another embodiment of the present invention;

[0026] Figure 4 is a schematic diagram of a control flow of an asynchronous motor of a household appliance according to another embodiment of the present invention;

[0027] Figure 5 is a schematic diagram of a control flow of an asynchronous motor of a household appliance according to another embodiment of the present invention;

[0028] Figure 6 is a flow chart of a method for controlling a household appliance according to an embodiment of the present invention.

[0029] Figure numerals: household appliance-1; housing-11; asynchronous motor-12; controller-13. DETAILED DESCRIPTION

[0030] Embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. Embodiments of the present invention are described in detail below.

[0031] Combine the following Figure 1-Figure 6 The household electrical appliances according to the embodiments of the present invention are described by way of example.

[0032] like Figure 1 As shown, the household appliance 1 of the embodiment of the present invention comprises: a housing 11, an asynchronous motor 12 and a controller 13, wherein:

[0033] The asynchronous motor 12 is arranged in the housing 11 and is used to operate according to the AC input voltage. The controller 13 is configured to: generate a harmonic voltage of the AC input voltage; superimpose the harmonic voltage on the AC input voltage as the input voltage of the asynchronous motor 12, and increase or decrease the amplitude of the harmonic voltage according to a preset step size to adjust the amplitude of the harmonic voltage; in the process of adjusting the amplitude of the harmonic voltage, collect the vibration signal generated by the asynchronous motor 12 under different harmonic voltage amplitudes; determine whether to stop adjusting the amplitude of the harmonic voltage according to the amplitude of the vibration signal and the preset harmonic voltage amplitude range to reduce the amplitude of the vibration signal.

[0034] Specifically, the household appliance 1 includes a housing 11, and an asynchronous motor 12 is disposed in the housing 11. The housing 11 can be used to protect the asynchronous motor 12. The asynchronous motor 12 can operate according to the AC input voltage, that is, the asynchronous motor 12 operates according to the voltage and frequency provided by the power supply, thereby driving the normal operation of the household appliance 1. During the operation of the household appliance 1, the embodiment of the present invention adjusts the AC input voltage and injects a certain amplitude of the power frequency harmonic voltage to reduce the 2 times power frequency vibration generated by the AC input voltage. It can be understood that the power frequency is the frequency of the AC input voltage, including but not limited to 50Hz and 60Hz. When the frequency of the injected power frequency harmonic voltage is 3 times the power frequency, the 3 times power frequency harmonic voltage will cause the asynchronous motor to generate a vibration signal of 2 times the power frequency and a vibration signal of 4 times the power frequency, and the vibration signal of 2 times the power frequency will offset the vibration signal of 2 times the power frequency generated by the original power frequency AC input voltage, and because the amplitude of the vibration signal decreases with the increase of the frequency order, the vibration signal of 4 times the power frequency generated by the 3 times power frequency harmonic voltage will be smaller than the vibration signal of 2 times the power frequency. Therefore, after injecting a certain amplitude of the power frequency harmonic voltage, the amplitude of the vibration signal can be reduced to achieve vibration reduction and noise reduction. It can be understood that the power frequency harmonic voltage includes but is not limited to the harmonic voltage of 3 times the power frequency. The embodiment of the present invention is described by taking the harmonic voltage of 3 times the power frequency as an example.

[0035] Specifically, a harmonic voltage of 3 times the power frequency can be generated, and after the harmonic voltage is superimposed on the AC input voltage, it is used as the input voltage of the asynchronous motor 12. Then, the amplitude of the harmonic voltage can be increased or decreased according to the preset step size to adjust the amplitude of the harmonic voltage, thereby realizing the adjustment of the input voltage amplitude of the asynchronous motor 12. In the process of adjusting the amplitude of the harmonic voltage, a vibration sensor, such as an acceleration sensor, a speed sensor or a displacement sensor, is used to collect the vibration signal generated by the asynchronous motor 12 under different harmonic voltage amplitudes in real time to evaluate the amplitude of the vibration signal generated by the asynchronous motor 12 under different input voltage states. Further, it can be determined whether it is necessary to stop adjusting the amplitude of the harmonic voltage based on the amplitude of the vibration signal and the preset harmonic voltage amplitude range, that is, if the harmonic voltage amplitude exceeds the preset range, the amplitude of the harmonic voltage can be controlled to stop adjusting the amplitude of the harmonic voltage, so as to limit the amplitude of the harmonic voltage within the preset range, ensure the normal operation of the asynchronous motor, and reduce the amplitude of the vibration signal at the same time, so as to achieve the purpose of reducing vibration and improving the operating stability of the household appliance 1. In summary, by injecting harmonic voltage into the asynchronous motor and adjusting the amplitude of the harmonic voltage, the amplitude of the vibration signal can be reduced, thereby improving the vibration reduction effect, reducing the noise of household appliances, and further improving the performance of household appliances.

[0036] In a specific embodiment, the harmonic voltage injected into the asynchronous motor can be directly generated by the controller 13, or can be obtained by conditioning the industrial frequency input voltage through a conditioning module, which is not limited here.

[0037] According to the household appliance 1 of the embodiment of the present invention, the harmonic voltage of the AC input voltage is superimposed on the AC input voltage as the input voltage of the asynchronous motor 12, and then the amplitude of the harmonic voltage is increased or decreased according to a preset step size to adjust the amplitude of the harmonic voltage. In the process of adjusting the amplitude of the harmonic voltage, the vibration signal generated by the asynchronous motor 12 under different amplitudes of the harmonic voltage is collected; according to the amplitude of the vibration signal and the preset harmonic voltage amplitude range, it is determined whether to stop adjusting the amplitude of the harmonic voltage to reduce the amplitude of the vibration signal, thereby improving the vibration reduction effect, reducing the noise of the household appliance, and then improving the performance of the household appliance.

[0038] In some embodiments, whether to stop adjusting the amplitude of the harmonic voltage is determined according to the amplitude of the vibration signal and a preset harmonic voltage amplitude range. The controller 13 is specifically configured as follows: when the amplitude of the harmonic voltage is increased according to a preset step size, it is determined whether the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage reaches the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage; when it is determined that the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage does not reach the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, the amplitude of the harmonic voltage continues to be increased according to the preset step size until the amplitude of the vibration signal reaches the first extreme. minimum value; or, when the amplitude of the vibration signal has not reached the first minimum value, and the amplitude of the current harmonic voltage has reached the upper limit value of the preset harmonic voltage amplitude range, stop adjusting the amplitude of the harmonic voltage; when it is judged that the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage has reached the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, reduce the amplitude of the harmonic voltage according to a preset step size until the amplitude of the vibration signal reaches the second minimum value; or, when the amplitude of the vibration signal has not reached the second minimum value, and the amplitude of the current harmonic voltage has reached the lower limit value of the preset harmonic voltage amplitude range, stop adjusting the amplitude of the harmonic voltage.

[0039] In an embodiment, Figure 2As shown, during the operation of the household appliance 1, in the process of determining whether to stop adjusting the amplitude of the harmonic voltage according to the amplitude of the vibration signal and the preset harmonic voltage amplitude range, when the amplitude of the harmonic voltage is increased according to the preset step size, it is judged whether the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage reaches the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage. If it is judged that the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage does not reach the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, it is considered that the amplitude of the vibration signal decreases with the increase of the amplitude of the harmonic voltage, that is, when the amplitude of the harmonic voltage increases, the amplitude of the vibration signal can be reduced, and the amplitude of the harmonic voltage continues to be increased according to the preset step size until the amplitude of the vibration signal reaches the first minimum value, or when the amplitude of the vibration signal does not reach the first minimum value, when the amplitude of the current harmonic voltage reaches the upper limit value of the preset harmonic voltage amplitude range, the amplitude of the harmonic voltage is stopped. It is understandable that, in the process of increasing the amplitude of the harmonic voltage according to the preset step size, when the amplitude of the vibration signal reaches the first minimum value, and the amplitude of the harmonic voltage does not reach the upper limit of the preset harmonic voltage amplitude range, it is considered that when the amplitude of the harmonic voltage is adjusted to the amplitude of the harmonic voltage corresponding to the first minimum value, the vibration signal generated is small, and vibration reduction and noise reduction can be achieved. When the amplitude of the vibration signal does not reach the first minimum value, but the amplitude of the current harmonic voltage has reached the upper limit of the preset harmonic voltage amplitude range, in order to ensure the normal operation of the asynchronous motor, the amplitude of the harmonic voltage is no longer increased. It should be noted that the preset harmonic voltage amplitude range can be determined according to experiments and pre-stored in the controller. Exemplarily, the preset harmonic voltage amplitude range is 0-20% of the standard voltage of the asynchronous motor.

[0040] In an embodiment, in the process of increasing the amplitude of the harmonic voltage according to a preset step size, if it is judged that the amplitude of the vibration signal corresponding to the current amplitude of the harmonic voltage reaches the amplitude of the vibration signal corresponding to the previous amplitude of the harmonic voltage, it is considered that the amplitude of the vibration signal increases with the increase of the amplitude of the harmonic voltage, that is, when the amplitude of the harmonic voltage increases, the amplitude of the vibration signal cannot be reduced, and the amplitude of the harmonic voltage is no longer increased, and the amplitude of the harmonic voltage is reduced according to the preset step size until the amplitude of the vibration signal reaches the second minimum value, or when the amplitude of the vibration signal has not reached the second minimum value, when the amplitude of the current harmonic voltage reaches the lower limit of the preset harmonic voltage amplitude range, the amplitude of the harmonic voltage is stopped from being adjusted. It is understandable that, in the process of reducing the amplitude of the harmonic voltage according to the preset step size, when the amplitude of the vibration signal reaches the second minimum value, and the amplitude of the harmonic voltage does not reach the lower limit of the preset harmonic voltage amplitude range, it is considered that when the amplitude of the harmonic voltage is adjusted to the amplitude of the harmonic voltage corresponding to the second minimum value, the vibration signal generated is small, and vibration reduction and noise reduction can be achieved. When the amplitude of the vibration signal does not reach the second minimum value, but the amplitude of the current harmonic voltage has reached the lower limit of the preset harmonic voltage amplitude range, in order to ensure the normal operation of the asynchronous motor, the amplitude of the harmonic voltage is no longer reduced.

[0041] In summary, in the process of increasing the amplitude of the harmonic voltage according to the preset step size, determining whether to stop adjusting the amplitude of the harmonic voltage according to the amplitude of the vibration signal and the preset harmonic voltage amplitude range can reduce the vibration signal, thereby achieving vibration reduction and noise reduction, while keeping the amplitude of the harmonic voltage within the preset range, making the operation of the asynchronous motor 12 more stable, thereby effectively controlling the vibration and noise of household appliances, and improving the performance of household appliances.

[0042] In some embodiments, whether to stop adjusting the amplitude of the harmonic voltage is determined according to the amplitude of the vibration signal and a preset harmonic voltage amplitude range. The controller 13 is specifically configured as follows: when reducing the amplitude of the harmonic voltage according to a preset step size, judging whether the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage reaches the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage; when judging that the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage does not reach the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, continuing to reduce the amplitude of the harmonic voltage according to the preset step size until the amplitude of the vibration signal reaches the third pole. minimum value; or, when the amplitude of the vibration signal does not reach the third minimum value and the amplitude of the current harmonic voltage reaches the lower limit value of the preset harmonic voltage amplitude range, stop adjusting the amplitude of the harmonic voltage; when it is judged that the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage reaches the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, increase the amplitude of the harmonic voltage according to a preset step size until the amplitude of the vibration signal reaches the fourth minimum value; or, when the amplitude of the vibration signal does not reach the fourth minimum value and the amplitude of the current harmonic voltage reaches the upper limit value of the preset harmonic voltage amplitude range, stop adjusting the amplitude of the harmonic voltage.

[0043] In an embodiment, Figure 2 As shown, during the operation of the household appliance 1, in the process of determining whether to stop adjusting the amplitude of the harmonic voltage according to the amplitude of the vibration signal and the preset harmonic voltage amplitude range, when the amplitude of the harmonic voltage is reduced according to the preset step size, it is judged whether the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage reaches the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage. If it is judged that the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage does not reach the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, that is, when the amplitude of the harmonic voltage decreases, the amplitude of the vibration signal can be reduced, and the amplitude of the harmonic voltage continues to be reduced according to the preset step size until the amplitude of the vibration signal reaches the third minimum value, or when the amplitude of the vibration signal does not reach the third minimum value, when the amplitude of the current harmonic voltage reaches the lower limit of the preset harmonic voltage amplitude range, the amplitude of the harmonic voltage is stopped. It is understandable that, in the process of reducing the amplitude of the harmonic voltage according to the preset step size, when the amplitude of the vibration signal reaches the third minimum value, and the amplitude of the harmonic voltage does not reach the lower limit of the preset harmonic voltage amplitude range, it is considered that when the amplitude of the harmonic voltage is adjusted to the amplitude of the harmonic voltage corresponding to the third minimum value, the vibration signal generated is small, and vibration reduction and noise reduction can be achieved. When the amplitude of the vibration signal does not reach the third minimum value, but the amplitude of the current harmonic voltage has reached the lower limit of the preset harmonic voltage amplitude range, in order to ensure the normal operation of the asynchronous motor, the amplitude of the harmonic voltage is no longer reduced. It should be noted that the preset harmonic voltage amplitude range can be determined according to experiments and pre-stored in the controller. Exemplarily, the preset harmonic voltage amplitude range is 0-20% of the standard voltage of the asynchronous motor.

[0044] In an embodiment, in the process of reducing the amplitude of the harmonic voltage according to a preset step size, if it is determined that the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage reaches the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, that is, when the amplitude of the harmonic voltage decreases, the amplitude of the vibration signal cannot be reduced, then the amplitude of the harmonic voltage is no longer reduced, and the amplitude of the harmonic voltage is increased according to the preset step size until the amplitude of the vibration signal reaches the fourth minimum value, or when the amplitude of the vibration signal does not reach the fourth minimum value, when the amplitude of the current harmonic voltage reaches the upper limit of the preset harmonic voltage amplitude range, then the amplitude of the harmonic voltage is stopped from being adjusted. It can be understood that in the process of increasing the amplitude of the harmonic voltage according to the preset step size, when the amplitude of the vibration signal reaches the fourth minimum value and the amplitude of the harmonic voltage does not reach the upper limit of the preset harmonic voltage amplitude range, it is considered that when the amplitude of the harmonic voltage is adjusted to the amplitude of the harmonic voltage corresponding to the fourth minimum value, the vibration signal generated is small, and vibration reduction and noise reduction can be achieved. When the amplitude of the vibration signal has not reached the fourth minimum value, but the amplitude of the current harmonic voltage has reached the upper limit of the preset harmonic voltage amplitude range, in order to ensure the normal operation of the asynchronous motor, the amplitude of the harmonic voltage is no longer increased.

[0045] In summary, in the process of reducing the amplitude of the harmonic voltage according to the preset step size, determining whether to stop adjusting the amplitude of the harmonic voltage according to the amplitude of the vibration signal and the preset harmonic voltage amplitude range can reduce the vibration signal, thereby achieving vibration reduction and noise reduction, while keeping the amplitude of the harmonic voltage within the preset range, making the operation of the asynchronous motor 12 more stable, thereby effectively controlling the vibration and noise of household appliances, and improving the performance of household appliances.

[0046] In some embodiments, after stopping adjusting the amplitude of the harmonic voltage, the controller 13 is further configured to: obtain the current change amplitude of the asynchronous motor 12; and determine whether to repeat the step of increasing or decreasing the amplitude of the harmonic voltage according to a preset step size based on the current change amplitude.

[0047] In an embodiment, Figure 3 As shown, during the operation of the household appliance 1, after stopping adjusting the amplitude of the harmonic voltage, the current change amplitude of the asynchronous motor 12 can be obtained in real time through the built-in sensor and the corresponding preset algorithm, and according to the current change amplitude, it is determined whether to repeat the step of increasing or decreasing the amplitude of the harmonic voltage according to the preset step size, so that when the load changes, the operating status of the asynchronous motor 12 can be understood in time, so that the asynchronous motor can generate a smaller vibration signal under different load conditions, thereby improving the vibration reduction effect, reducing the noise of the household appliance, and then improving the performance of the household appliance.

[0048] In some embodiments, whether to repeat the step of increasing or decreasing the amplitude of the harmonic voltage according to a preset step length is determined according to the current change amplitude, and the controller 13 is specifically configured as follows: when the current change amplitude does not reach the preset current change amplitude, the step of increasing or decreasing the amplitude of the harmonic voltage according to the preset step length is not performed. When the current change amplitude reaches the preset current change amplitude, the step of increasing or decreasing the amplitude of the harmonic voltage according to the preset step length is repeated.

[0049] In an embodiment, Figure 3 As shown, when judging whether it is necessary to repeatedly increase or decrease the amplitude of the harmonic voltage according to the preset step length according to the current change amplitude, if the current change amplitude does not reach the preset current change amplitude, it is considered that the operation state of the asynchronous motor 12 has changed slightly, and the vibration signal corresponding to the current harmonic voltage amplitude is still the minimum vibration signal, and has not yet reached the level where the harmonic voltage amplitude needs to be adjusted. At this time, the step of increasing or decreasing the amplitude of the harmonic voltage according to the preset step length is not performed; if the current change amplitude reaches the preset current change amplitude, it is considered that the operation state of the asynchronous motor 12 has changed significantly, and the vibration signal corresponding to the current harmonic voltage amplitude is not the minimum vibration signal. At this time, the step of increasing or decreasing the amplitude of the harmonic voltage according to the preset step length is repeated, so as to reduce the vibration signal generated by the asynchronous motor by adjusting the amplitude of the harmonic voltage, and achieve the best vibration reduction effect. It should be noted that the preset current change amplitude needs to be determined based on the characteristics, working conditions and speed changes of the asynchronous motor 12, and is pre-stored in the controller.

[0050] In some embodiments, when determining the amplitude of the vibration signal, the controller 13 is specifically configured to: perform Fourier transform on the vibration signal according to a preset frequency step; determine, based on the Fourier transform result, a first amplitude corresponding to the vibration signal with a frequency twice the frequency of the AC input voltage, and a second amplitude corresponding to the vibration signal with a frequency four times the frequency of the AC input voltage; and determine the amplitude of the vibration signal based on the first amplitude and the second amplitude.

[0051] In an embodiment, Figure 4As shown, when determining the amplitude of the vibration signal, the vibration signal can be Fourier transformed according to the preset frequency step size, so as to obtain the amplitude of the vibration signal at various frequencies, that is, the first amplitude corresponding to the vibration signal with a frequency twice the frequency of the AC input voltage and the second amplitude corresponding to the vibration signal with a frequency four times the frequency of the AC input voltage can be obtained, and then the amplitude of the vibration signal is determined according to the first amplitude and the second amplitude, so as to adjust the amplitude of the harmonic voltage according to the amplitude of the vibration signal and the preset harmonic voltage amplitude range, so as to achieve the purpose of reducing the vibration of twice the power frequency generated by the original AC input voltage. Among them, the preset frequency step size can be a set fixed value, such as 0.5Hz, 1Hz. It can be understood that the frequency twice the frequency of the AC input voltage and the frequency four times the frequency of the AC input voltage correspond to the frequency twice and the frequency four times the original power frequency AC input voltage.

[0052] In some embodiments, when determining the amplitude of the vibration signal according to the first amplitude and the second amplitude, the controller 13 is specifically configured to: calculate the root mean square of the first amplitude and the second amplitude; and use the root mean square as the amplitude of the vibration signal.

[0053] In an embodiment, Figure 4 As shown, the first amplitude corresponding to the vibration signal of the frequency twice the AC input voltage frequency and the second amplitude corresponding to the vibration signal of the frequency four times the AC input voltage frequency can be obtained by Fourier transform. The first amplitude and the second amplitude are squared and summed, and then the square root of the sum is taken to obtain the root mean square of the first amplitude and the second amplitude, which can be used as the amplitude of the vibration signal. It can be understood that by taking the root mean square of the first amplitude and the second amplitude, the influence of the frequency twice and the frequency four times the AC input voltage frequency on the vibration signal can be comprehensively considered, so as to obtain a more accurate determination of the amplitude of the vibration signal.

[0054] In some embodiments, before performing Fourier transform on the vibration signal according to the preset frequency step, the controller 13 is further configured to: determine the preset frequency step according to the speed fluctuation range of the asynchronous motor 12 .

[0055] In the embodiment, before Fourier transforming the vibration signal according to the preset frequency step, it is necessary to determine the preset frequency step according to the speed fluctuation range of the asynchronous motor 12, so as to perform Fourier transform on the vibration signal according to the preset frequency step to obtain a more accurate vibration signal amplitude. Among them, the speed fluctuation range of the asynchronous motor 12 is the range in which the speed of the asynchronous motor 12 changes during operation. It can be understood that different asynchronous motors 12 correspond to different speed fluctuation ranges.

[0056] In some embodiments, when determining the preset frequency step according to the speed fluctuation range of the asynchronous motor 12, the controller 13 is specifically configured as follows:

[0057] Δf>(2*ΔV) / 60*2;

[0058] Wherein, Δf is a preset frequency step, and ΔV is a speed fluctuation range of the asynchronous motor 12 .

[0059] In an embodiment, the preset frequency step can be determined according to the above formula, wherein Δf represents the preset frequency step, and ΔV is the speed fluctuation range of the asynchronous motor 12. Specifically, the preset frequency step Δf needs to be greater than 2 times the speed fluctuation range ΔV divided by 60 seconds and then multiplied by 2, that is, the preset frequency step has a lower limit. When the preset frequency step is greater than the lower limit, the amplitude of the vibration signal at different frequencies can be accurately obtained by Fourier transform, so as to ensure that after the vibration signal is Fourier transformed according to the preset frequency step, a first amplitude corresponding to a frequency twice the AC input voltage frequency and a second amplitude corresponding to a frequency four times the AC input voltage frequency can be obtained.

[0060] Reference below Figure 5 The control flow of the asynchronous motor 12 in the household appliance 1 according to the embodiment of the present invention is described.

[0061] like Figure 5 As shown, the control process of the asynchronous motor 12 in the household appliance 1 according to the embodiment of the present invention at least includes steps S31 to S41.

[0062] Step S31, the asynchronous motor 12 is started.

[0063] Step S32: generating a harmonic voltage of the AC input voltage.

[0064] Step S33 , superimposing the harmonic voltage onto the AC input voltage to serve as the input voltage of the asynchronous motor 12 .

[0065] Step S34, collecting vibration signals generated by the asynchronous motor 12 under different harmonic voltage amplitudes.

[0066] Step S35, performing Fourier transform on the vibration signal according to a preset frequency step; determining, based on the Fourier transform result, a first amplitude corresponding to the vibration signal with a frequency twice the frequency of the AC input voltage, and a second amplitude corresponding to the vibration signal with a frequency four times the frequency of the AC input voltage; and taking the root mean square of the first amplitude and the second amplitude as the amplitude of the vibration signal.

[0067] Step S36, increasing (or decreasing) the amplitude of the harmonic voltage according to a preset step size.

[0068] Step S37, adjusting the power supply according to the adjusted harmonic voltage amplitude and outputting it to the asynchronous motor 12.

[0069] Step S38, collecting the vibration signal generated by the asynchronous motor 12 under different harmonic voltage amplitudes again.

[0070] Step S39, perform Fourier transform on the vibration signal again to obtain the amplitude of the vibration signal, determine whether the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage reaches the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, and based on the judgment result, increase (or decrease) the amplitude of the harmonic voltage according to a preset step size.

[0071] Step S40, until the amplitude of the vibration signal reaches a minimum value; or, when the amplitude of the vibration signal does not reach a minimum value and the amplitude of the current harmonic voltage reaches the upper limit (or lower limit) of the preset harmonic voltage amplitude range, stop adjusting the amplitude of the harmonic voltage and keep the current harmonic voltage amplitude continuously output.

[0072] Step S41, obtaining the current change amplitude of the asynchronous motor 12, when the current change amplitude does not reach the preset current change amplitude, step S36 is not executed, and the current harmonic voltage amplitude is maintained. When the current change amplitude reaches the preset current change amplitude, step S36 is repeated to achieve the best damping effect.

[0073] According to the household appliance 1 of the embodiment of the present invention, the harmonic voltage of the AC input voltage is superimposed on the AC input voltage as the input voltage of the asynchronous motor 12, and then the amplitude of the harmonic voltage is increased or decreased according to a preset step size to adjust the amplitude of the harmonic voltage, and in the process of adjusting the amplitude of the harmonic voltage, the vibration signal generated by the asynchronous motor 12 under different amplitudes of the harmonic voltage is collected; according to the amplitude of the vibration signal and the preset harmonic voltage amplitude range, it is determined whether to stop adjusting the amplitude of the harmonic voltage to reduce the amplitude of the vibration signal, thereby improving the vibration reduction effect, reducing the noise of the household appliance, and further improving the performance of the household appliance. Further, after stopping adjusting the amplitude of the harmonic voltage, the current change amplitude of the asynchronous motor 12 is obtained, and according to the current change amplitude, it is determined whether to repeat the step of increasing or decreasing the amplitude of the harmonic voltage according to the preset step size, so that the best vibration reduction effect can be achieved when the load changes.

[0074] Reference below Figure 6 A control method for a household appliance according to an embodiment of the present invention is described.

[0075] like Figure 6 As shown, the control method of the household appliance according to the embodiment of the present invention at least includes steps S1 to S3.

[0076] Step S1, generating a harmonic voltage of an AC input voltage.

[0077] Step S2, after superimposing the harmonic voltage on the AC input voltage, use it as the input voltage of the asynchronous motor, and increase or decrease the amplitude of the harmonic voltage according to a preset step size to adjust the amplitude of the harmonic voltage.

[0078] Step S3, in the process of adjusting the amplitude of the harmonic voltage, collecting vibration signals generated by the asynchronous motor under different amplitudes of the harmonic voltage.

[0079] Step S4, determining whether to stop adjusting the amplitude of the harmonic voltage according to the amplitude of the vibration signal and a preset harmonic voltage amplitude range to reduce the amplitude of the vibration signal.

[0080] In some embodiments, determining whether to stop adjusting the amplitude of the harmonic voltage to reduce the amplitude of the vibration signal is performed based on the amplitude of the vibration signal and a preset harmonic voltage amplitude range, and further includes: when the amplitude of the harmonic voltage is increased according to a preset step size, judging whether the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage reaches the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage; when judging that the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage does not reach the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, continuing to increase the amplitude of the harmonic voltage according to the preset step size until the amplitude of the vibration signal reaches the first minimum value; or, when the amplitude of the vibration signal does not reach the first minimum value, and the amplitude of the current harmonic voltage reaches the upper limit value of the preset harmonic voltage amplitude range, stop adjusting the amplitude of the harmonic voltage; when it is judged that the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage reaches the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, reduce the amplitude of the harmonic voltage according to a preset step size until the amplitude of the vibration signal reaches the second minimum value; or, when the amplitude of the vibration signal does not reach the second minimum value, and the amplitude of the current harmonic voltage reaches the lower limit value of the preset harmonic voltage amplitude range, stop adjusting the amplitude of the harmonic voltage.

[0081] In some embodiments, determining whether to stop adjusting the amplitude of the harmonic voltage to reduce the amplitude of the vibration signal is performed based on the amplitude of the vibration signal and a preset harmonic voltage amplitude range, and further includes: when reducing the amplitude of the harmonic voltage according to a preset step size, judging whether the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage reaches the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage; when judging that the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage does not reach the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, continuing to reduce the amplitude of the harmonic voltage according to the preset step size until the amplitude of the vibration signal reaches the amplitude of the previous harmonic voltage. three minimum values; or, when the amplitude of the vibration signal does not reach the third minimum value, and the amplitude of the current harmonic voltage reaches the lower limit of the preset harmonic voltage amplitude range, stop adjusting the amplitude of the harmonic voltage; when it is judged that the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage reaches the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, increase the amplitude of the harmonic voltage according to the preset step size until the amplitude of the vibration signal reaches the fourth minimum value; or, when the amplitude of the vibration signal does not reach the fourth minimum value, and the amplitude of the current harmonic voltage reaches the upper limit of the preset harmonic voltage amplitude range, stop adjusting the amplitude of the harmonic voltage.

[0082] In some embodiments, after the harmonic voltage is superimposed on the AC input voltage, it is used as the input voltage of the asynchronous motor, and the amplitude of the harmonic voltage is increased or decreased according to a preset step size to adjust the amplitude of the harmonic voltage. It also includes: obtaining the current change amplitude of the asynchronous motor; determining whether to repeat the step of increasing or decreasing the amplitude of the harmonic voltage according to the preset step size based on the current change amplitude.

[0083] In some embodiments, after the harmonic voltage is superimposed on the AC input voltage, it is used as the input voltage of the asynchronous motor, and the amplitude of the harmonic voltage is increased or decreased according to a preset step size to adjust the amplitude of the harmonic voltage, and further includes: when the current change amplitude does not reach the preset current change amplitude, the step of increasing or decreasing the amplitude of the harmonic voltage according to the preset step size is not performed. When the current change amplitude reaches the preset current change amplitude, the step of increasing or decreasing the amplitude of the harmonic voltage according to the preset step size is repeatedly performed.

[0084] In some embodiments, in the process of adjusting the amplitude of the harmonic voltage, the vibration signal generated by the asynchronous motor under different harmonic voltage amplitudes is collected, and it also includes: performing Fourier transform on the vibration signal according to a preset frequency step; determining, based on the Fourier transform result, a first amplitude corresponding to the vibration signal with a frequency twice the frequency of the AC input voltage, and a second amplitude corresponding to the vibration signal with a frequency four times the frequency of the AC input voltage; and determining the amplitude of the vibration signal based on the first amplitude and the second amplitude.

[0085] In some embodiments, in the process of adjusting the amplitude of the harmonic voltage, collecting the vibration signal generated by the asynchronous motor under different harmonic voltage amplitudes also includes: calculating the root mean square of the first amplitude and the second amplitude; and using the root mean square as the amplitude of the vibration signal.

[0086] In some embodiments, in the process of adjusting the amplitude of the harmonic voltage, collecting the vibration signal generated by the asynchronous motor under different amplitudes of the harmonic voltage also includes: determining the preset frequency step according to the speed fluctuation range of the asynchronous motor.

[0087] In some embodiments, when the preset frequency step is determined according to the speed fluctuation range of the asynchronous motor, it specifically includes: Δf>(2*ΔV) / 60*2;

[0088] Wherein, Δf is the preset frequency step, and ΔV is the speed fluctuation range of the asynchronous motor.

[0089] It should be noted that when controlling the asynchronous motor of the household appliance, its specific implementation method is similar to the specific implementation method of the household appliance of any one of the above-mentioned embodiments of the present invention. Therefore, for a detailed exemplary description of the control process of the household appliance, please refer to the aforementioned relevant description part about the household appliance. In order to reduce redundancy, it will not be repeated here.

[0090] According to the control method of the household appliance of the embodiment of the present invention, the harmonic voltage of the AC input voltage is superimposed on the AC input voltage as the input voltage of the asynchronous motor, and then the amplitude of the harmonic voltage is increased or decreased according to a preset step size to adjust the amplitude of the harmonic voltage, and in the process of adjusting the amplitude of the harmonic voltage, the vibration signal generated by the asynchronous motor under different amplitudes of the harmonic voltage is collected; according to the amplitude of the vibration signal and the preset harmonic voltage amplitude range, it is determined whether to stop adjusting the amplitude of the harmonic voltage to reduce the amplitude of the vibration signal, thereby improving the vibration reduction effect, reducing the noise of the household appliance, and further improving the performance of the household appliance. Further, after stopping adjusting the amplitude of the harmonic voltage, the current change amplitude of the asynchronous motor 12 is obtained, and according to the current change amplitude, it is determined whether to repeat the step of increasing or decreasing the amplitude of the harmonic voltage according to the preset step size, so that the best vibration reduction effect can be achieved when the load changes.

[0091] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0092] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A household appliance, characterized in that: include: case; an asynchronous motor, disposed in the housing and configured to operate according to an AC input voltage; A controller configured to: generate a harmonic voltage of the AC input voltage; After the harmonic voltage is superimposed on the AC input voltage, it is used as the input voltage of the asynchronous motor, and the amplitude of the harmonic voltage is increased or decreased according to a preset step size to adjust the amplitude of the harmonic voltage; In the process of adjusting the amplitude of the harmonic voltage, collecting vibration signals generated by the asynchronous motor under different amplitudes of the harmonic voltage; Whether to stop adjusting the amplitude of the harmonic voltage is determined according to the amplitude of the vibration signal and a preset harmonic voltage amplitude range to reduce the amplitude of the vibration signal.

2. The household appliance according to claim 1, characterized in that: Determining whether to stop adjusting the amplitude of the harmonic voltage according to the amplitude of the vibration signal and a preset harmonic voltage amplitude range, the controller is specifically configured as follows: When the amplitude of the harmonic voltage is increased according to a preset step size, it is determined whether the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage reaches the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage; When it is determined that the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage does not reach the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, continue to increase the amplitude of the harmonic voltage according to a preset step size until the amplitude of the vibration signal reaches a first minimum value; or, when the amplitude of the vibration signal does not reach the first minimum value and the amplitude of the current harmonic voltage reaches an upper limit of the preset harmonic voltage amplitude range, stop adjusting the amplitude of the harmonic voltage; When it is determined that the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage reaches the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, the amplitude of the harmonic voltage is reduced according to a preset step size until the amplitude of the vibration signal reaches a second minimum value; or, when the amplitude of the vibration signal does not reach the second minimum value and the amplitude of the current harmonic voltage reaches the lower limit of the preset harmonic voltage amplitude range, the amplitude of the harmonic voltage is stopped from being adjusted.

3. The household appliance according to claim 1, characterized in that: Determining whether to stop adjusting the amplitude of the harmonic voltage according to the amplitude of the vibration signal and a preset harmonic voltage amplitude range, the controller is specifically configured as follows: When the amplitude of the harmonic voltage is reduced according to a preset step size, it is determined whether the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage reaches the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage; When it is determined that the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage does not reach the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, continue to reduce the amplitude of the harmonic voltage according to the preset step size until the amplitude of the vibration signal reaches a third minimum value; or, when the amplitude of the vibration signal does not reach the third minimum value and the amplitude of the current harmonic voltage reaches the lower limit of the preset harmonic voltage amplitude range, stop adjusting the amplitude of the harmonic voltage; When it is determined that the amplitude of the vibration signal corresponding to the amplitude of the current harmonic voltage reaches the amplitude of the vibration signal corresponding to the amplitude of the previous harmonic voltage, the amplitude of the harmonic voltage is increased according to a preset step size until the amplitude of the vibration signal reaches a fourth minimum value; or, when the amplitude of the vibration signal does not reach the fourth minimum value and the amplitude of the current harmonic voltage reaches the upper limit of the preset harmonic voltage amplitude range, the amplitude of the harmonic voltage is stopped from being adjusted.

4. The household appliance according to claim 2 or 3, characterized in that: After stopping adjusting the amplitude of the harmonic voltage, the controller is further configured to: Obtaining a current variation amplitude of the asynchronous motor; Whether to repeat the step of increasing or decreasing the amplitude of the harmonic voltage according to a preset step size is determined according to the current change amplitude.

5. The household appliance according to claim 4, characterized in that: Determining whether to repeat the step of increasing or decreasing the amplitude of the harmonic voltage according to a preset step size according to the current change amplitude, the controller is specifically configured as follows: When the current change amplitude does not reach the preset current change amplitude, the step of increasing or decreasing the amplitude of the harmonic voltage according to the preset step size is not performed; When the current variation amplitude reaches the preset current variation amplitude, the step of increasing or decreasing the amplitude of the harmonic voltage according to a preset step size is repeatedly performed.

6. The household appliance according to any one of claims 1 to 3, characterized in that: When determining the amplitude of the vibration signal, the controller is specifically configured to: Performing Fourier transform on the vibration signal according to a preset frequency step size; According to the Fourier transform result, determining a first amplitude corresponding to a vibration signal with a frequency twice the frequency of the AC input voltage, and a second amplitude corresponding to a vibration signal with a frequency four times the frequency of the AC input voltage; The amplitude of the vibration signal is determined according to the first amplitude and the second amplitude.

7. The household appliance according to claim 6, characterized in that: When determining the amplitude of the vibration signal according to the first amplitude and the second amplitude, the controller is specifically configured as follows: Calculating a root mean square of the first amplitude and the second amplitude; The root mean square is taken as the amplitude of the vibration signal.

8. The household appliance according to claim 6, characterized in that: Before performing Fourier transform on the vibration signal according to the preset frequency step, the controller is further configured to: The preset frequency step is determined according to the speed fluctuation range of the asynchronous motor.

9. The household appliance according to claim 8, characterized in that: When the preset frequency step is determined according to the speed fluctuation range of the asynchronous motor, the controller is specifically configured as follows: Δf>(2*ΔV) / 60*2; Wherein, Δf is the preset frequency step, and ΔV is the speed fluctuation range of the asynchronous motor.

10. A method for controlling a household appliance, characterized in that: include: generating harmonic voltages of the AC input voltage; After the harmonic voltage is superimposed on the AC input voltage, it is used as the input voltage of the asynchronous motor, and the amplitude of the harmonic voltage is increased or decreased according to a preset step size to adjust the amplitude of the harmonic voltage; In the process of adjusting the amplitude of the harmonic voltage, collecting vibration signals generated by the asynchronous motor under different amplitudes of the harmonic voltage; Whether to stop adjusting the amplitude of the harmonic voltage is determined according to the amplitude of the vibration signal and a preset harmonic voltage amplitude range to reduce the amplitude of the vibration signal.

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