Household appliance and control method thereof

Abstract

The invention discloses a household appliance and a control method thereof, and the household appliance comprises a shell, a transmission device which is arranged in the shell, is connected with a load, and is used for driving the load to rotate during transmission, a permanent magnet synchronous motor which is arranged in the shell and is used for driving the transmission device to transmit during operation, and a controller which is configured to obtain the transmission ratio of the transmission device, the actual rotating speed, the number of pole pairs and the rotational inertia of the permanent magnet synchronous motor; determining the fluctuation component of the load rotating speed according to the actual rotating speed and pole pair number of the permanent magnet synchronous motor and the transmission ratio of the transmission device; determining a compensation value of the load torque according to the fluctuation component of the load rotating speed and the rotational inertia of the permanent magnet synchronous motor; and the torque instruction or the current instruction of the permanent magnet synchronous motor is compensated according to the compensation value of the load torque so as to suppress periodic fluctuation of the load, so that the household appliance reduces operation noise and operates stably, and the use experience of a user is improved.

Description

Technical Field

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

[0002] Household electrical appliances, such as variable frequency washing machines, generally have a transmission device, and the motor drives the load to rotate through a transmission belt. However, when such appliances are running, the load will fluctuate periodically. For example, when the weight distribution of the load is too uneven, the household appliance will be eccentric due to excessive load fluctuations, causing the washing tub to hit the wall and excessive noise. In the prior art, the washing machine detects eccentricity. If the load fluctuation is too large, it will stop running and restart after the load is evenly distributed by rotating at a certain speed. This process takes a long time and affects the working efficiency of the appliance. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the purpose of the present invention is to provide a household appliance and a control method thereof.

[0004] The present invention proposes a household appliance, which includes: a housing; a transmission device, which is arranged in the housing and connected to a load, and is used to drive the load to rotate during transmission; a permanent magnet synchronous motor, which is arranged in the housing, and is used to drive the transmission device to transmit during operation; a controller, which is configured to: obtain the transmission ratio of the transmission device, and the actual speed, pole pair number and moment of inertia of the permanent magnet synchronous motor; determine the fluctuation component of the load speed according to the actual speed and pole pair number of the permanent magnet synchronous motor, and the transmission ratio of the transmission device; determine the compensation value of the load torque according to the fluctuation component of the load speed and the moment of inertia of the permanent magnet synchronous motor; and compensate the torque command or current command of the permanent magnet synchronous motor according to the compensation value of the load torque to suppress the periodic fluctuation of the load.

[0005] In addition, the household appliance according to the embodiment of the present invention may also have the following additional technical features:

[0006] Furthermore, when determining the fluctuating component of the load speed according to the actual speed and pole pair number of the permanent magnet synchronous motor and the transmission ratio of the transmission device, the controller is configured to: determine the speed of the load according to the actual speed and pole pair number of the permanent magnet synchronous motor and the transmission ratio of the transmission device; determine the fluctuating component of the load speed according to the actual speed of the permanent magnet synchronous motor and the speed of the load.

[0007] Further, when determining the speed of the load according to the actual speed and pole pair number of the permanent magnet synchronous motor and the transmission ratio of the transmission device, the controller is configured as follows:

[0008]

[0009] Wherein, ω0 is the speed of the load, ω ^ is the actual speed of the permanent magnet synchronous motor, P is the number of pole pairs of the permanent magnet synchronous motor, l gr is the transmission ratio of the transmission device.

[0010] Furthermore, when determining the fluctuating component of the load speed based on the actual speed of the permanent magnet synchronous motor and the speed of the load, the controller is configured to: take the speed of the load as the center frequency, perform band-pass filtering on the actual speed of the permanent magnet synchronous motor, and obtain the fluctuating component of the load speed.

[0011] Furthermore, after determining the compensation value of the load torque according to the fluctuation component of the load speed and the rotational inertia of the permanent magnet synchronous motor, the controller is further configured to: correct the compensation value of the load torque to obtain a corrected compensation value of the load torque.

[0012] Furthermore, when correcting the compensation value of the load torque, the controller is configured to: multiply the compensation value of the load torque by a preset correction coefficient to obtain a corrected compensation value of the load torque.

[0013] Further, when determining the compensation value of the load torque according to the fluctuation component of the load speed and the rotational inertia of the permanent magnet synchronous motor, the controller is configured as follows:

[0014]

[0015] Wherein, Δτ is the compensation value of the load torque, J is the moment of inertia of the permanent magnet synchronous motor, ω lgr is the fluctuation component of the load speed.

[0016] Furthermore, when compensating the torque command of the permanent magnet synchronous motor according to the compensation value of the load torque, the controller is configured to: use the sum of the current torque command value of the permanent magnet synchronous motor and the compensation value of the load torque as the compensated torque command.

[0017] Furthermore, when compensating the current command of the permanent magnet synchronous motor according to the compensation value of the load torque, the controller is configured to use the ratio of the compensated torque command to the torque constant as the compensated current command.

[0018] According to the household appliance of the embodiment of the invention, the household appliance includes: a housing, a transmission device, a permanent magnet synchronous motor and a controller. The housing is used to wrap and protect the internal components of the household appliance, including the transmission device, the permanent magnet synchronous motor and the controller; the transmission device is arranged in the housing and connected to the load, and is used to drive the load to rotate during transmission; the permanent magnet synchronous motor is arranged in the housing, and is used to drive the transmission device to transmit during operation; the controller is configured to: obtain the transmission ratio of the transmission device, and the actual speed, pole pair number and moment of inertia of the permanent magnet synchronous motor; determine the fluctuation component of the load speed according to the actual speed and pole pair number of the permanent magnet synchronous motor, and the transmission ratio of the transmission device; determine the compensation value of the load torque according to the fluctuation component of the load speed and the moment of inertia of the permanent magnet synchronous motor; compensate the torque command or current command of the permanent magnet synchronous motor according to the compensation value of the load torque, so as to suppress the periodic fluctuation of the load, reduce the operating noise of the household appliance and run smoothly, and improve the user experience. Furthermore, after determining the compensation value of the load torque based on the fluctuating component of the load speed and the rotational inertia of the permanent magnet synchronous motor, the compensation value of the load torque is corrected to obtain a corrected compensation value of the load torque, and the torque command or current command of the permanent magnet synchronous motor is compensated according to the corrected compensation value of the load torque, thereby further improving the stability of the operation of household appliances.

[0019] In response to the above-mentioned problems, the present invention also proposes a control method for household appliances, comprising: obtaining the transmission ratio of a transmission device, and the actual speed, pole pair number and moment of inertia of a permanent magnet synchronous motor; determining the fluctuation component of the load speed according to the actual speed and pole pair number of the permanent magnet synchronous motor, and the transmission ratio of the transmission device; determining a compensation value of the load torque according to the fluctuation component of the load speed and the moment of inertia of the permanent magnet synchronous motor; and compensating the torque command or current command of the permanent magnet synchronous motor according to the compensation value of the load torque to suppress the periodic fluctuation of the load.

[0020] According to the control method of the household appliance of the embodiment of the present invention, by obtaining the transmission ratio of the transmission device, and the actual speed, pole pair number and moment of inertia of the permanent magnet synchronous motor, the fluctuation component of the load speed is determined according to the actual speed and pole pair number of the permanent magnet synchronous motor and the transmission ratio of the transmission device, the compensation value of the load torque is determined according to the fluctuation component of the load speed and the moment of inertia of the permanent magnet synchronous motor, and the torque command or current command of the permanent magnet synchronous motor is compensated according to the compensation value of the load torque, so as to suppress the periodic fluctuation of the load, reduce the operating noise of the household appliance and run smoothly, and improve the user experience. Further, after determining the compensation value of the load torque according to the fluctuation component of the load speed and the moment of inertia of the permanent magnet synchronous motor, the compensation value of the load torque is corrected to obtain the corrected compensation value of the load torque, and the torque command or current command of the permanent magnet synchronous motor is compensated according to the corrected compensation value of the load torque, so as to further improve the stability of the operation 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 schematic structural diagram of a household appliance according to an embodiment of the present invention;

[0024] Figure 2 is a flow chart for determining the fluctuation component of the load speed according to the actual speed and pole pair number of the permanent magnet synchronous motor and the transmission ratio of the transmission device according to one embodiment of the present invention;

[0025] Figure 3 is a structural block diagram of load fluctuation suppression according to an embodiment of the present invention;

[0026] Figure 4 is a current waveform diagram output by a permanent magnet synchronous motor when load fluctuation suppression is not performed according to an embodiment of the present invention;

[0027] Figure 5 is a current waveform diagram output by a permanent magnet synchronous motor after load fluctuation suppression according to an 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. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0031] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0032] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] Reference below Figure 1-Figure 6 A home appliance and a control method thereof according to an embodiment of the present invention are described.

[0034] Figure 1 Schematic diagram of the structure of a household appliance according to an embodiment of the present invention. Figure 1As shown, a household appliance 10 includes: a housing 11; a transmission device 12, which is arranged in the housing and connected to the load, and is used to drive the load to rotate during transmission; a permanent magnet synchronous motor 13, which is arranged in the housing, and is used to drive the transmission device to transmit during operation; a controller 14, which is configured to: obtain the transmission ratio of the transmission device, and the actual speed, pole pair number and rotational inertia of the permanent magnet synchronous motor; determine the fluctuation component of the load speed according to the actual speed and pole pair number of the permanent magnet synchronous motor, and the transmission ratio of the transmission device; determine the compensation value of the load torque according to the fluctuation component of the load speed and the rotational inertia of the permanent magnet synchronous motor; compensate the torque command or current command of the permanent magnet synchronous motor according to the compensation value of the load torque to suppress the periodic fluctuation of the load.

[0035] Specifically, household appliances such as variable frequency washing machines generally have transmission devices, which drive the load to rotate under the drive of the permanent magnet synchronous motor. The transmission ratio is the ratio of the mechanical speed of the permanent magnet synchronous motor to the load speed. When the household appliance is running, the load torque will fluctuate periodically. In a cycle of the load torque fluctuation, the torques of different phases are different. The embodiment of the present invention determines the compensation value of the load torque by analyzing the periodic fluctuation of the load speed to perform compensation control of the load fluctuation phase, that is, the periodic fluctuation of the load speed is reflected in the motor drive through the transmission ratio, and the load fluctuation phase is compensated. Control, thereby suppressing the load fluctuation within a certain range, improving the working state of the household appliance, and making it run more stably. Specifically, assuming that the fluctuation amount is a sine wave, by compensating the torque command or current command of the permanent magnet synchronous motor, increasing the torque when the load torque is large, and reducing the torque when the load torque is small, so that it maintains a uniform speed, the household appliance can reduce the operating noise and run smoothly. In a specific embodiment, the transmission ratio of the transmission device, the pole pair number and the moment of inertia of the permanent magnet synchronous motor are inherent parameters of the household appliance and can be pre-stored in the controller. The actual speed of the permanent magnet synchronous motor can be inferred by speed sensor sampling or position observer algorithm.

[0036] In one embodiment of the present invention, Figure 2 As shown, when determining the fluctuation component of the load speed according to the actual speed and pole pair number of the permanent magnet synchronous motor and the transmission ratio of the transmission device, the controller is configured to: determine the speed of the load according to the actual speed and pole pair number of the permanent magnet synchronous motor and the transmission ratio of the transmission device; determine the fluctuation component of the load speed according to the actual speed of the permanent magnet synchronous motor and the speed of the load.

[0037] Specifically, since the ratio between the actual speed and the mechanical speed of the permanent magnet synchronous motor is the number of pole pairs of the permanent magnet synchronous motor, the speed of the load can be determined according to the actual speed and the number of pole pairs of the permanent magnet synchronous motor and the transmission ratio of the transmission device. Figure 3As shown, when the speed of the load is determined according to the actual speed and pole pair number of the permanent magnet synchronous motor and the transmission ratio of the transmission device, the controller is configured as follows:

[0038]

[0039] Among them, ω0 is the speed of the load, ω ^ is the actual speed of the permanent magnet synchronous motor, P is the number of pole pairs of the permanent magnet synchronous motor, l gr is the transmission ratio of the transmission.

[0040] Furthermore, after determining the speed of the load, the embodiment of the present invention determines the fluctuation component of the load speed according to the actual speed of the permanent magnet synchronous motor and the speed of the load to determine the compensation value of the load torque, and compensates the torque command or current command of the permanent magnet synchronous motor according to the compensation value of the load torque, and performs compensation control on the load fluctuation phase, so as to reflect the periodic fluctuation of the load speed to the motor drive through the transmission ratio, suppress the load fluctuation within a certain range, improve the working state of the household appliance, and make it run more stably.

[0041] In one embodiment of the present invention, when determining the fluctuating component of the load speed based on the actual speed of the permanent magnet synchronous motor and the speed of the load, the controller is configured to: take the speed of the load as the center frequency, perform bandpass filtering on the actual speed of the permanent magnet synchronous motor, and obtain the fluctuating component of the load speed.

[0042] In a specific embodiment, Figure 3 As shown in the figure, BPF (Band Pass Filter), PI (Proportional Integral Controller), SVM (Space Vector Modulation) and PM (Permanent Magnet Motor). In the embodiment of the present invention, the speed of the load, i.e., ω0, is used as the center frequency to perform band-pass filtering on the actual speed of the permanent magnet synchronous motor, that is, a sine wave with ω0 as the angular frequency is input into the BPF for band-pass filtering, and the amplitude of ω0 is extracted by the BPF, which corresponds to the fluctuation component ω of the load speed ω0. lgr , so that the periodic fluctuation of the load speed ω0 is reflected in the motor drive, so as to * Or the current command is used to compensate for the load fluctuation phase, thereby suppressing the load fluctuation within a certain range. In other implementations, the fluctuation component ω of the load speed can also be extracted based on the Fourier fundamental wave extraction algorithm. lgrIt is understandable that, since the embodiment of the present invention adopts a bandpass filter, the phase delay after the compensation control is minimized, and the compensation control is more accurate.

[0043] In one embodiment of the present invention, after determining the compensation value of the load torque according to the fluctuation component of the load speed and the rotational inertia of the permanent magnet synchronous motor, the controller is further configured to: correct the compensation value of the load torque to obtain the corrected compensation value of the load torque. Specifically, when correcting the compensation value of the load torque, the controller is configured to: multiply the compensation value of the load torque by a preset correction coefficient to obtain the corrected compensation value of the load torque.

[0044] Specifically, according to the fluctuation component ω of the load speed lgr The compensation value τ of the load torque is determined by the rotational inertia J of the permanent magnet synchronous motor shift When the compensation amount is too large, some household appliances may trigger the protection of the permanent magnet synchronous motor. Therefore, the embodiment of the present invention uses a preset correction coefficient K gr Compensation value τ for load torque shift Corrections are made to further improve the stability of home appliance operation.

[0045] In a specific embodiment, Figure 3 As shown, the controller uses the correction factor K gr Correct the compensation value of the load torque by multiplying the compensation value of the load torque by the correction coefficient K gr The corrected load torque compensation value can be obtained. It should be noted that the correction coefficient K gr It can be pre-calibrated by experiments and stored in the controller, and different household appliances correspond to different correction coefficients.

[0046] In one embodiment of the present invention, when determining the compensation value of the load torque according to the fluctuation component of the load speed and the rotational inertia of the permanent magnet synchronous motor, the controller is configured as follows:

[0047]

[0048] Among them, Δτ is the compensation value of the load torque, J is the moment of inertia of the permanent magnet synchronous motor, ω lgr is the fluctuation component of load speed.

[0049] Specifically, the rotational inertia J of the permanent magnet synchronous motor is an inherent parameter of the permanent magnet synchronous motor. The controller combines this parameter with the above formula to calculate the compensation value τ of the load torque: shift Then, the compensation value is added to the torque command τ of the permanent magnet synchronous motor. *(It can also be converted into a current compensation value, and the current compensation value is compensated to the current command of the permanent magnet synchronous motor), so that the periodic fluctuation of the load torque can be suppressed. In other implementations, the compensation value of the load torque can also be obtained by performing gain control on the extracted fluctuation component of the load speed through algorithms such as Fourier fundamental wave extraction, which will not be described in detail here.

[0050] In one embodiment of the present invention, when compensating the torque command of the permanent magnet synchronous motor according to the compensation value of the load torque, the controller is configured to: use the sum of the current torque command value of the permanent magnet synchronous motor and the compensation value of the load torque as the compensated torque command.

[0051] Specifically, if Figure 3 As shown, τ * is the current torque command value of the permanent magnet synchronous motor, and the load torque compensation value is the corrected load torque compensation value τ shift . The current torque command value τ of the permanent magnet synchronous motor * and the corrected load torque compensation value τ shift The sum is taken as the compensated torque command, that is, the compensation value τ of the load torque shift Positive compensation to the current torque command value τ of the permanent magnet synchronous motor * In order to suppress the load torque fluctuation.

[0052] In one embodiment of the present invention, when compensating the current command of the permanent magnet synchronous motor according to the compensation value of the load torque, the controller is configured to: use the ratio of the compensated torque command to the torque constant as the compensated current command.

[0053] Specifically, since the torque command τ of the permanent magnet synchronous motor * The ratio of the current command to the torque constant is the torque constant. Therefore, the compensated torque command can be converted into the compensated current command, that is, the load torque fluctuation can be suppressed by compensating the current current command of the permanent magnet synchronous motor. In a specific embodiment, Figure 3 As shown, the torque constant is Kt, and the ratio of the compensated torque command to the torque constant Kt is used as the compensated current command I q * .

[0054] In practical applications, taking the washing machine system as an example, when the transmission ratio is l gr When is 10 and the number of motor pole pairs P is 2, Figure 4 is the torque command τ for the permanent magnet synchronous motor * Or when the current command is compensated, the current waveform of the permanent magnet synchronous motor output is constant, or has a small fluctuation; Figure 5 is the torque command τ for the permanent magnet synchronous motor* Or after the current command is compensated, the current waveform of the permanent magnet synchronous motor output has obvious periodic fluctuations in the output envelope, and the fluctuation period is the mechanical period of the load. Figure 4 and Figure 5 It can be seen that according to the compensation value τ of the load torque shift Torque command τ for permanent magnet synchronous motor * Or current command compensation can suppress the periodic fluctuation of load torque. Figure 4 and Figure 5 The current waveform can be detected by Figure 3 in i u 、i v or w Any one of the currents is obtained.

[0055] In one embodiment of the present invention, the household appliance includes at least one of an air conditioner, a washing machine, and a refrigerator.

[0056] Specifically, the household electrical appliances include at least one of an air conditioner, a washing machine, and a refrigerator, and any drive system using a permanent magnet synchronous motor including a transmission device is applicable.

[0057] According to an embodiment of the present invention, the household appliance comprises: a housing, a transmission device, a permanent magnet synchronous motor and a controller. The housing is used to wrap and protect the internal components of the household appliance, including the transmission device and the permanent magnet synchronous motor. The transmission device is arranged in the housing and connected to the load, and is used to drive the load to rotate during transmission; the permanent magnet synchronous motor is arranged in the housing, and is used to drive the transmission device to transmit during operation; the controller is configured to: obtain the transmission ratio of the transmission device, and the actual speed, pole pair number and moment of inertia of the permanent magnet synchronous motor, determine the fluctuation component of the load speed according to the actual speed and pole pair number of the permanent magnet synchronous motor, and the transmission ratio of the transmission device, determine the compensation value of the load torque according to the fluctuation component of the load speed and the moment of inertia of the permanent magnet synchronous motor, and compensate the torque command or current command of the permanent magnet synchronous motor according to the compensation value of the load torque, so as to suppress the periodic fluctuation of the load, reduce the operating noise of the household appliance and run smoothly, and improve the user experience. Furthermore, after determining the compensation value of the load torque based on the fluctuating component of the load speed and the rotational inertia of the permanent magnet synchronous motor, the compensation value of the load torque is corrected to obtain a corrected compensation value of the load torque, and the torque command or current command of the permanent magnet synchronous motor is compensated according to the corrected compensation value of the load torque, thereby further improving the stability of the operation of household appliances.

[0058] A further embodiment of the present invention also discloses a control method for household electrical appliances, such as Figure 6 As shown, the method comprises the following steps:

[0059] Step S1: Acquire the transmission ratio of the transmission device, and the actual speed, pole pair number and moment of inertia of the permanent magnet synchronous motor.

[0060] Step S2: determining the fluctuation component of the load speed according to the actual speed and pole pair number of the permanent magnet synchronous motor and the transmission ratio of the transmission device.

[0061] Step S3: Determine the compensation value of the load torque according to the fluctuation component of the load speed and the rotational inertia of the permanent magnet synchronous motor.

[0062] Step S4: Compensate the torque command or current command of the permanent magnet synchronous motor according to the compensation value of the load torque to suppress the periodic fluctuation of the load.

[0063] In one embodiment of the present invention, the fluctuation component of the load speed is determined according to the actual speed and pole pair number of the permanent magnet synchronous motor and the transmission ratio of the transmission device, including: determining the speed of the load according to the actual speed and pole pair number of the permanent magnet synchronous motor and the transmission ratio of the transmission device; determining the fluctuation component of the load speed according to the actual speed of the permanent magnet synchronous motor and the speed of the load.

[0064] In one embodiment of the present invention, the speed of the load is determined according to the actual speed and pole pair number of the permanent magnet synchronous motor and the transmission ratio of the transmission device, including:

[0065]

[0066] Among them, ω0 is the speed of the load, ω ^ is the actual speed of the permanent magnet synchronous motor, P is the number of pole pairs of the permanent magnet synchronous motor, l gr is the transmission ratio of the transmission.

[0067] In one embodiment of the present invention, the fluctuation component of the load speed is determined according to the actual speed of the permanent magnet synchronous motor and the speed of the load, including: taking the speed of the load as the center frequency, performing bandpass filtering on the actual speed of the permanent magnet synchronous motor, and obtaining the fluctuation component of the load speed.

[0068] In one embodiment of the present invention, after determining the compensation value of the load torque according to the fluctuation component of the load speed and the rotational inertia of the permanent magnet synchronous motor, the method further includes: correcting the compensation value of the load torque to obtain a corrected compensation value of the load torque.

[0069] In one embodiment of the present invention, the compensation value of the load torque is corrected, including: multiplying the compensation value of the load torque by a preset correction coefficient to obtain a corrected compensation value of the load torque.

[0070] In one embodiment of the present invention, the compensation value of the load torque is determined according to the fluctuation component of the load speed and the rotational inertia of the permanent magnet synchronous motor, including:

[0071]

[0072] Among them, Δτ is the compensation value of the load torque, J is the moment of inertia of the permanent magnet synchronous motor, ω lgr is the fluctuation component of load speed.

[0073] In one embodiment of the present invention, compensating the torque command of the permanent magnet synchronous motor according to the compensation value of the load torque includes: taking the sum of the current torque command value of the permanent magnet synchronous motor and the compensation value of the load torque as the compensated torque command.

[0074] In one embodiment of the present invention, the current command of the permanent magnet synchronous motor is compensated according to the compensation value of the load torque, including: taking the ratio of the compensated torque command to the torque constant as the compensated current command.

[0075] It should be noted that when the control method of the household appliance in the embodiment of the present invention controls the household appliance, its specific implementation method is similar to the specific implementation method of the household appliance in the embodiment of the present invention. Please refer to the description of the system part for details. In order to reduce redundancy, it will not be repeated here.

[0076] According to the control method of the household appliance of the embodiment of the present invention, by obtaining the transmission ratio of the transmission device, and the actual speed, pole pair number and moment of inertia of the permanent magnet synchronous motor, the fluctuation component of the load speed is determined according to the actual speed and pole pair number of the permanent magnet synchronous motor and the transmission ratio of the transmission device, the compensation value of the load torque is determined according to the fluctuation component of the load speed and the moment of inertia of the permanent magnet synchronous motor, and the torque command or current command of the permanent magnet synchronous motor is compensated according to the compensation value of the load torque, so as to suppress the periodic fluctuation of the load, reduce the operating noise of the household appliance and run smoothly, and improve the user experience. Further, after determining the compensation value of the load torque according to the fluctuation component of the load speed and the moment of inertia of the permanent magnet synchronous motor, the compensation value of the load torque is corrected to obtain the corrected compensation value of the load torque, and the torque command or current command of the permanent magnet synchronous motor is compensated according to the corrected compensation value of the load torque, so as to further improve the stability of the operation of the household appliance.

[0077] 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.

[0078] 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; A transmission device, disposed in the housing and connected to the load, for driving the load to rotate during transmission; A permanent magnet synchronous motor is disposed in the housing and is used to drive the transmission device during operation; A controller is configured to: obtain a transmission ratio of the transmission device, and an actual rotation speed, a pole pair number, and a moment of inertia of the permanent magnet synchronous motor; Determining the fluctuation component of the load speed according to the actual speed and pole pair number of the permanent magnet synchronous motor and the transmission ratio of the transmission device; Determining a compensation value of the load torque according to the fluctuation component of the load speed and the rotational inertia of the permanent magnet synchronous motor; The torque command or current command of the permanent magnet synchronous motor is compensated according to the compensation value of the load torque to suppress the periodic fluctuation of the load.

2. The household appliance according to claim 1, characterized in that: When determining the fluctuation component of the load speed according to the actual speed and pole pair number of the permanent magnet synchronous motor and the transmission ratio of the transmission device, the controller is configured as follows: Determining the speed of the load according to the actual speed and pole pair number of the permanent magnet synchronous motor and the transmission ratio of the transmission device; The fluctuation component of the load speed is determined according to the actual speed of the permanent magnet synchronous motor and the speed of the load.

3. The household appliance according to claim 2, characterized in that: When determining the speed of the load according to the actual speed and pole pair number of the permanent magnet synchronous motor and the transmission ratio of the transmission device, the controller is configured as follows: Wherein, ω0 is the speed of the load, ω ^ is the actual speed of the permanent magnet synchronous motor, P is the number of pole pairs of the permanent magnet synchronous motor, l gr is the transmission ratio of the transmission device.

4. The household appliance according to claim 2, characterized in that: When determining the fluctuation component of the load speed according to the actual speed of the permanent magnet synchronous motor and the speed of the load, the controller is configured as follows: The rotation speed of the load is taken as the center frequency, and the actual rotation speed of the permanent magnet synchronous motor is subjected to band-pass filtering to obtain the fluctuation component of the load rotation speed.

5. The household appliance according to claim 1, characterized in that: After determining the compensation value of the load torque according to the fluctuation component of the load speed and the rotational inertia of the permanent magnet synchronous motor, the controller is further configured to: The load torque compensation value is corrected to obtain a corrected load torque compensation value.

6. The household appliance according to claim 5, characterized in that: When correcting the compensation value of the load torque, the controller is configured as follows: The load torque compensation value is multiplied by a preset correction coefficient to obtain a corrected load torque compensation value.

7. The household appliance according to claim 1, characterized in that: When determining the compensation value of the load torque according to the fluctuation component of the load speed and the rotational inertia of the permanent magnet synchronous motor, the controller is configured as follows: Wherein, Δτ is the compensation value of the load torque, J is the moment of inertia of the permanent magnet synchronous motor, ω lgr is the fluctuation component of the load speed.

8. The household appliance according to claim 1, characterized in that: When compensating the torque command of the permanent magnet synchronous motor according to the compensation value of the load torque, the controller is configured as follows: The sum of the current torque command value of the permanent magnet synchronous motor and the compensation value of the load torque is used as the compensated torque command.

9. The household appliance according to claim 8, characterized in that: When compensating the current command of the permanent magnet synchronous motor according to the compensation value of the load torque, the controller is configured as follows: The ratio of the compensated torque command to the torque constant is used as the compensated current command.

10. A method for controlling a household appliance, characterized in that: include: Obtain the transmission ratio of the transmission device, as well as the actual speed, pole pair number and moment of inertia of the permanent magnet synchronous motor; Determining the fluctuation component of the load speed according to the actual speed and pole pair number of the permanent magnet synchronous motor and the transmission ratio of the transmission device; Determining a compensation value of the load torque according to the fluctuation component of the load speed and the rotational inertia of the permanent magnet synchronous motor; The torque command or current command of the permanent magnet synchronous motor is compensated according to the compensation value of the load torque to suppress the periodic fluctuation of the load.

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