Household appliance and control method thereof

Abstract

The invention discloses a household appliance and a control method thereof. The household appliance comprises a shell; the permanent magnet synchronous motor is arranged in the shell and is used for operating according to the direct current input voltage; the controller is configured to obtain the period of the high-frequency square wave signal of the dr axis of the current injection assumed coordinate system in the operation process of the permanent magnet synchronous motor; when the period of the currently injected high-frequency square wave signal is ended, determining the period of the next injected high-frequency square wave signal according to the period of the currently injected high-frequency square wave signal; and injecting the next injected high-frequency square wave signal into the dr axis of the assumed coordinate system, taking the next injected high-frequency square wave signal as the current injected high-frequency square wave signal, and returning to execute the step of determining the period of the next injected high-frequency square wave signal. The noise amplitude of the fixed injection signal frequency at a certain frequency point is dispersed through the variable-frequency high-frequency square wave signal injected to the dr axis, so that the injection noise and the electromagnetic interference are reduced.

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] When controlling a permanent magnet synchronous motor without a position sensor, a special algorithm is required to estimate the rotor position. In the medium and high speed operation stage, the rotor position is generally estimated by observing the back electromotive force, and in the zero speed and low speed stages, the rotor position is generally estimated by the high-frequency injection method. The industry has developed technologies for injecting sine waves in a stationary coordinate system, injecting sine waves in a rotating coordinate system, and injecting square waves in a rotating coordinate system. However, the above-mentioned traditional high-frequency signal injection method uses a fixed frequency signal injection, which concentrates the noise on a certain frequency and produces sharp and harsh noise. 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 provides a household appliance, comprising: a housing; a permanent magnet synchronous motor, arranged in the housing, and configured to operate according to a DC input voltage; and a controller, configured to: during the operation of the permanent magnet synchronous motor, obtain a d currently injected into an assumed coordinate system. r The period of the high-frequency square wave signal of the axis; when the period of the currently injected high-frequency square wave signal ends, the period of the next injected high-frequency square wave signal is determined according to the period of the currently injected high-frequency square wave signal; the next injected high-frequency square wave signal is injected into the d of the assumed coordinate system. r axis, and use the next injected high-frequency square wave signal as the currently injected high-frequency square wave signal, and return to execute the step of determining the period of the next injected high-frequency square wave signal.

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

[0006] Further, when determining the period of the next injected high-frequency square wave signal based on the period of the currently injected high-frequency square wave signal, the controller is configured to: use the period of the currently injected high-frequency square wave signal as the period of the next injected high-frequency square wave signal after fluctuating it up or down by 2N carrier cycles, where N is an integer.

[0007] Further, the next injected high-frequency square wave signal is injected into the assumed coordinate system d r Before the injection is performed on the axis, the controller is further configured to: obtain the d rThe amplitude of the high-frequency square wave signal of the axis; determine the amplitude of the next injected high-frequency square wave signal according to the period and amplitude of the currently injected high-frequency square wave signal and the period of the next injected high-frequency square wave signal.

[0008] Further, when determining the amplitude of the next injected high-frequency square wave signal according to the period and amplitude of the currently injected high-frequency square wave signal and the period of the next injected high-frequency square wave signal, the controller is configured to execute the following formula:

[0009] F 下 =F 当 *T 当 / T 下 ;

[0010] Among them, F 下 is the amplitude of the next injected high-frequency square wave signal, F 当 is the amplitude of the currently injected high-frequency square wave signal, T 当 is the period of the high-frequency square wave signal injected currently, T 下 The next injected high frequency square wave signal period.

[0011] Furthermore, the controller is further configured to: in the assumed coordinate system d r After the high-frequency square wave signal is injected into the shaft, the three-phase current signal of the permanent magnet synchronous motor is obtained; the angle between the assumed coordinate system and the rotating coordinate system is determined according to the three-phase current signal; and the real rotor position of the permanent magnet synchronous motor is determined according to the angle between the assumed coordinate system and the rotating coordinate system.

[0012] Further, when determining the angle between the assumed coordinate system and the rotating coordinate system according to the three-phase current signal, the controller is configured to: determine the q of the assumed coordinate system according to the three-phase current signal r The response current of the axis; according to the q r The response current of the shaft determines the angle between the assumed coordinate system and the rotating coordinate system.

[0013] Further, the q of the assumed coordinate system is determined according to the three-phase current signal r When the response current of the axis is measured, the controller is configured to: obtain the q by Clark transformation and Park transformation of the three-phase current signal r The response current signal of the axis.

[0014] Further, according to the q r When the angle between the assumed coordinate system and the rotating coordinate system is determined by the response current of the axis, the controller is configured as follows:

[0015]

[0016]

[0017]

[0018] Among them, θ err is the angle between the assumed coordinate system and the rotated coordinate system, I q[k] is the q corresponding to the kth carrier period r The response current of the shaft, I q[k-1] is the q corresponding to the k-1th carrier period r The response current of the axis, T is the carrier period, u dh is the d of the permanent magnet synchronous motor after the high frequency square wave signal is injected r Shaft voltage, L d , L q are the d-axis inductance and q-axis inductance of the permanent magnet synchronous motor respectively.

[0019] Furthermore, when determining the true rotor position of the permanent magnet synchronous motor based on the angle between the assumed coordinate system and the rotating coordinate system, the controller is configured to: use a phase-locked loop to adjust the angle between the assumed coordinate system and the rotating coordinate system; when the angle between the assumed coordinate system and the rotating coordinate system is zero, obtain the true rotor position of the permanent magnet synchronous motor.

[0020] According to an embodiment of the present invention, the household appliance comprises: a housing, a permanent magnet synchronous motor and a controller. The permanent magnet synchronous motor is arranged in the housing and is used to operate according to a DC input voltage. The controller is configured to: during the operation of the permanent magnet synchronous motor, obtain the d currently injected into the assumed coordinate system. r The period of the high-frequency square wave signal of the axis is determined. When the period of the currently injected high-frequency square wave signal ends, the period of the next injected high-frequency square wave signal is determined according to the period of the currently injected high-frequency square wave signal, and the next injected high-frequency square wave signal is injected into the d of the assumed coordinate system. r axis, and takes the next injected high-frequency square wave signal as the currently injected high-frequency square wave signal, and returns to the step of determining the period of the next injected high-frequency square wave signal, by injecting it into d r The high-frequency square wave signal with a variable frequency on the axis is used to disperse the noise amplitude of the fixed injection signal frequency at a certain frequency point, thereby reducing the injection noise and electromagnetic interference. Further, the next injected high-frequency square wave signal is injected into the assumed coordinate system d rBefore the axis is on, the amplitude of the next injected high-frequency square wave signal is determined according to the period and amplitude of the currently injected high-frequency square wave signal and the period of the next injected high-frequency square wave signal, so that when the period (that is, the frequency) of the next injected high-frequency square wave signal changes continuously, the amplitude of the noise does not change, so that the amplitude of the noise is controlled, further reducing the injected noise and electromagnetic interference.

[0021] In view of the above problems, the present invention further proposes a control method for household electrical appliances, comprising: during the operation of the permanent magnet synchronous motor, obtaining the d currently injected into the assumed coordinate system r The period of the high-frequency square wave signal of the axis; when the period of the currently injected high-frequency square wave signal ends, the period of the next injected high-frequency square wave signal is determined according to the period of the currently injected high-frequency square wave signal; the next injected high-frequency square wave signal is injected into the d of the assumed coordinate system. r axis, and use the next injected high-frequency square wave signal as the currently injected high-frequency square wave signal, and return to execute the step of determining the period of the next injected high-frequency square wave signal.

[0022] According to the control method of the household appliance of the embodiment of the present invention, during the operation of the permanent magnet synchronous motor, the d currently injected into the assumed coordinate system is obtained. r The period of the high-frequency square wave signal of the axis is determined. When the period of the currently injected high-frequency square wave signal ends, the period of the next injected high-frequency square wave signal is determined according to the period of the currently injected high-frequency square wave signal, and the next injected high-frequency square wave signal is injected into the d of the assumed coordinate system. r axis, and takes the next injected high-frequency square wave signal as the currently injected high-frequency square wave signal, and returns to the step of determining the period of the next injected high-frequency square wave signal, by injecting it into d r The high-frequency square wave signal with a variable frequency on the axis is used to disperse the noise amplitude of the fixed injection signal frequency at a certain frequency point, thereby reducing the injection noise and electromagnetic interference. Further, the next injected high-frequency square wave signal is injected into the assumed coordinate system d r Before the axis is on, the amplitude of the next injected high-frequency square wave signal is determined according to the period and amplitude of the currently injected high-frequency square wave signal and the period of the next injected high-frequency square wave signal, so that when the period (that is, the frequency) of the next injected high-frequency square wave signal changes continuously, the amplitude of the noise does not change, so that the amplitude of the noise is controlled, further reducing the injected noise and electromagnetic interference.

[0023] 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

[0024] 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:

[0025] Figure 1 is a schematic structural diagram of a household appliance according to an embodiment of the present invention;

[0026] Figure 2 is a schematic diagram of an assumed coordinate system and a rotated coordinate system according to an embodiment of the present invention;

[0027] Figure 3 is a flow chart for determining the amplitude of the next injected high-frequency square wave signal according to one embodiment of the present invention;

[0028] Figure 4 is a waveform diagram of position sensorless control of a permanent magnet synchronous motor based on high-frequency square wave signal injection according to an embodiment of the present invention;

[0029] Figure 5 is a principle block diagram of position sensorless control of a permanent magnet synchronous motor based on high frequency square wave injection according to an embodiment of the present invention;

[0030] Figure 6 is a flow chart for determining the true rotor position of a permanent magnet synchronous motor according to one embodiment of the present invention;

[0031] Figure 7 is another flow chart for determining the true rotor position of a permanent magnet synchronous motor according to one embodiment of the present invention;

[0032] Figure 8 is a flow chart of determining the angle between the assumed coordinate system and the rotating coordinate system according to the three-phase current signal according to one embodiment of the present invention;

[0033] Fig. 9 is a flow chart of a method for controlling a household appliance according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] Reference below Figure 1-Figure 9 A home appliance and a control method thereof according to an embodiment of the present invention are described.

[0039] Figure 1 Schematic diagram of the structure of a household appliance according to an embodiment of the present invention. Figure 1 As shown, a household appliance comprises: a housing 10, a permanent magnet synchronous motor 20 and a controller 30. The permanent magnet synchronous motor 20 is arranged in the housing 10 and is used to operate according to a DC input voltage; the controller 30 is configured to: during the operation of the permanent magnet synchronous motor 20, obtain the d currently injected into the assumed coordinate system r The period of the high-frequency square wave signal of the axis; at the end of the period of the currently injected high-frequency square wave signal, the period of the next injected high-frequency square wave signal is determined according to the period of the currently injected high-frequency square wave signal; the next injected high-frequency square wave signal is injected into the d of the assumed coordinate system r axis, and use the next injected high-frequency square wave signal as the currently injected high-frequency square wave signal, and return to execute the step of determining the period of the next injected high-frequency square wave signal.

[0040] Specifically, if Figure 2 As shown, assuming the coordinate system is d rq r The rotating coordinate system is a dq coordinate system, the d-axis direction of the rotating coordinate system is the N-pole direction of the permanent magnet rotor in the permanent magnet synchronous motor 20, and the q-axis direction of the rotating coordinate system is the direction of rotating the d-axis direction by 90° counterclockwise. r When the period of the high-frequency square wave signal of the axis ends, the period of the next injected high-frequency square wave signal is determined according to the period of the currently injected high-frequency square wave signal, and the next injected high-frequency square wave signal is injected into the d of the assumed coordinate system. r axis, and then, the next injected high-frequency square wave signal is used as the currently injected high-frequency square wave signal, and the step of determining the period of the next injected high-frequency square wave signal is returned to execute, so that the injected high-frequency square wave signal changes from a fixed frequency to a variable frequency. Thus, compared with the noise amplitude at a certain frequency point generated by injecting a fixed-frequency high-frequency square wave signal, the embodiment of the present invention can be injected into d r The high-frequency square wave signal with changing frequency on the axis is used to disperse the noise amplitude of the fixed injection signal frequency at a certain frequency point, thereby reducing the injection noise and electromagnetic interference.

[0041] In one embodiment of the present invention, when determining the period of the next injected high-frequency square wave signal based on the period of the currently injected high-frequency square wave signal, the controller is configured to: use the period of the currently injected high-frequency square wave signal as the period of the next injected high-frequency square wave signal after fluctuating it up or down by 2N carrier cycles, where N is an integer.

[0042] Specifically, when the embodiment of the present invention determines the period of the next injected high-frequency square wave signal based on the period of the currently injected high-frequency square wave signal, the period of the next injected high-frequency square wave signal is set to fluctuate 2N carrier periods above and below the period of the currently injected high-frequency square wave signal, to ensure that the high-frequency square wave signal after the fluctuation is still a square wave signal.

[0043] In a specific embodiment, N takes a value of 1, for example, and the period of the currently injected high-frequency square wave signal is, for example, 10 carrier periods. Then the period of the next injected high-frequency square wave signal fluctuates by 2 carrier periods within 10 carrier periods. Then the period of the next injected high-frequency square wave signal changes in a pattern of 8, 10, 12, 10, 8, 10, 12, 10, 8… carrier periods. Similarly, if the period of the currently injected high-frequency square wave signal is, for example, carrier period T, then the period of the next injected high-frequency square wave signal changes in a pattern of T, T+2, T+4…T+2N, T+2N-2, T+2N-4…T+4, T+2, T… carrier periods. In this way, at the end of the period of the currently injected high-frequency square wave signal, the period of the next injected high-frequency square wave signal continues to change based on the period of the currently injected high-frequency square wave signal, so that the period of the high-frequency square wave signal injected into the assumed coordinate system is dr The high-frequency square wave signal on the axis is changed from a fixed frequency to a variable frequency, thereby reducing injected noise and electromagnetic interference.

[0044] It should be noted that the period of the currently injected high-frequency square wave signal is fluctuated upward or downward by 2N carrier cycles to obtain the period of the next injected high-frequency square wave signal. This changing rule is only an example. Any other rules that can cause the period of the next injected high-frequency square wave signal to change based on the period of the currently injected high-frequency square wave signal are within the protection scope of the present invention and will not be elaborated here.

[0045] In one embodiment of the present invention, Figure 3 As shown, the next injected high-frequency square wave signal is injected into the assumed coordinate system d r Before the axis is loaded, the controller is also configured to obtain the d of the current injection assumption coordinate system. r The amplitude of the high-frequency square wave signal of the axis; the amplitude of the next injected high-frequency square wave signal is determined according to the period and amplitude of the currently injected high-frequency square wave signal and the period of the next injected high-frequency square wave signal.

[0046] Specifically, as mentioned above, when the period of the next injected high-frequency square wave signal is constantly changing on the basis of the period of the currently injected high-frequency square wave signal, the noise amplitude of the fixed injected signal frequency at a certain frequency point can be dispersed, but the noise amplitude at this time will change with the period (that is, frequency) of the next injected high-frequency square wave signal. When the frequency of the next injected high-frequency square wave signal is higher, the amplitude of the noise is smaller; when the frequency of the next injected high-frequency square wave signal is lower, the amplitude of the noise is larger. Therefore, in the embodiment of the present invention, when the next injected high-frequency square wave signal is injected into the assumed coordinate system d r Before the axis is on, the amplitude of the next injected high-frequency square wave signal is determined according to the period and amplitude of the currently injected high-frequency square wave signal and the period of the next injected high-frequency square wave signal, so that when the period (that is, the frequency) of the next injected high-frequency square wave signal changes continuously, the amplitude of the noise does not change, so that the amplitude of the noise is controlled, further reducing the injected noise and electromagnetic interference.

[0047] In one embodiment of the present invention, when determining the amplitude of the next injected high-frequency square wave signal according to the period and amplitude of the currently injected high-frequency square wave signal and the period of the next injected high-frequency square wave signal, the controller is configured to execute the following formula:

[0048] F 下 =F 当 *T 当 / T 下 ;

[0049] Among them, F 下 is the amplitude of the next injected high-frequency square wave signal, F 当 is the amplitude of the currently injected high-frequency square wave signal, T 当 is the period of the currently injected high-frequency square wave signal, T 下 The next cycle of the injected high-frequency square wave signal.

[0050] Specifically, when the period of the next injected high-frequency square wave signal changes, its amplitude also changes accordingly. In a specific embodiment, the period of the currently injected high-frequency square wave signal is, for example, T, and the amplitude is, for example, U. The period of the next injected high-frequency square wave signal changes according to, for example, T-2N, T-2(N-1), T-2(N-2), ... T-4, T-2, T, T+2, T+4, T+2(N-2), T+2(N-1), T+2N ... carrier periods. Then, the amplitude of the next injected high-frequency square wave signal changes according to: For example, Figure 4 As shown in the figure, the period of the currently injected high-frequency square wave signal is 8 carrier cycles, and the voltage amplitude is U. When the period of the second injected high-frequency square wave signal is 10 carrier cycles, the voltage amplitude within the second injected high-frequency square wave signal period is When the period of the third injected high-frequency square wave signal is 12 carrier cycles, the voltage amplitude within the period of the third injected high-frequency square wave signal is In this way, when the period of the injected high-frequency square wave signal changes, the amplitude of the generated q-axis current response remains the same, and the amplitude of the noise does not change either, so that the amplitude of the noise is also controlled, further reducing the injected noise and electromagnetic interference.

[0051] In one embodiment of the present invention, Figure 6 As shown, the controller is also configured to: assume that the coordinate system is d r After a high-frequency square wave signal is injected into the shaft, the three-phase current signal of the permanent magnet synchronous motor is obtained; the angle between the assumed coordinate system and the rotating coordinate system is determined according to the three-phase current signal; and the real rotor position of the permanent magnet synchronous motor is determined according to the angle between the assumed coordinate system and the rotating coordinate system.

[0052] Specifically, if Figure 2 As shown, assuming the coordinate system is d r q r Coordinate system, the rotating coordinate system is the dq coordinate system, assuming that the angle between the coordinate system and the rotating coordinate system is θ err The mathematical model of permanent magnet synchronous motor is as follows:

[0053]

[0054]

[0055] Among them, u d is the d-axis voltage of the permanent magnet synchronous motor, u q The q-axis voltage of the permanent magnet synchronous motor, R is the phase resistance of the permanent magnet synchronous motor, I d is the d-axis current of the permanent magnet synchronous motor, I q is the q-axis current of the permanent magnet synchronous motor, L d is the d-axis inductance of the permanent magnet synchronous motor, L q is the q-axis inductance of the permanent magnet synchronous motor, ω is the electrical angular velocity of the permanent magnet synchronous motor, ψ f is the magnetic flux of the permanent magnet synchronous motor.

[0056] In the low-speed stage of the permanent magnet synchronous motor, when a high-frequency square wave signal is injected, the speed term and resistance term in the above equation can be ignored and simplified to:

[0057]

[0058]

[0059] Among them, u dh is the d-axis voltage of the permanent magnet synchronous motor after injecting the high-frequency square wave signal, u qh is the q-axis voltage of the permanent magnet synchronous motor after injecting the high-frequency square wave signal, L d is the d-axis inductance of the permanent magnet synchronous motor, L q is the q-axis inductance of the permanent magnet synchronous motor, I dh is the d-axis current of the permanent magnet synchronous motor after injecting the high-frequency square wave signal, I qh It is the q-axis current of the permanent magnet synchronous motor after injecting high-frequency square wave signal.

[0060] Then transform the above equation from the rotated coordinate system to the assumed coordinate system, and we can get:

[0061]

[0062]

[0063]

[0064]

[0065] Among them, I dh is the d-axis current of the permanent magnet synchronous motor after injecting the high-frequency square wave signal, I qh is the q-axis current of the permanent magnet synchronous motor after injecting high-frequency square wave signal, θ err is the angle between the assumed coordinate system and the rotated coordinate system, u dh is the d-axis voltage of the permanent magnet synchronous motor after injecting the high-frequency square wave signal, uqh is the q-axis voltage of the permanent magnet synchronous motor after injecting the high-frequency square wave signal, L d is the d-axis inductance of the permanent magnet synchronous motor, L q is the q-axis inductance of the permanent magnet synchronous motor.

[0066] Without installing the rotor position sensor and without performing rotor position locking, the rotor position angle θ r is unknown, here we can first estimate the rotor position angle by assuming a coordinate system: In this way, the relationship between the assumed coordinate system and the rotating coordinate system is established. err When it approaches 0, the real rotor position of the permanent magnet synchronous motor can be obtained.

[0067] Specifically, Figure 7 As shown, according to the angle θ between the assumed coordinate system and the rotating coordinate system err , determine the true rotor position of the permanent magnet synchronous motor, including: using a phase-locked loop to adjust the angle between the assumed coordinate system and the rotating coordinate system; when the angle θ between the assumed coordinate system and the rotating coordinate system err When is zero, the real rotor position of the permanent magnet synchronous motor is obtained. Figure 5 As shown in the figure, after extracting the angle error, the angle error θ between the assumed coordinate system and the rotating coordinate system is adjusted in real time through the phase-locking technology. err , so that the difference between its position angle and the rotation coordinate system is θ err =0, thereby achieving real-time tracking of the assumed coordinate system and the rotating coordinate system, so that the position information of the permanent magnet synchronous motor in the rotating coordinate system can be obtained without measuring through the rotor position sensor.

[0068] In one embodiment of the present invention, Figure 8 As shown, when determining the angle between the assumed coordinate system and the rotating coordinate system according to the three-phase current signal, the controller is configured to: determine the q of the assumed coordinate system according to the three-phase current signal r The response current of the axis; according to q r The response current of the axis determines the angle between the assumed coordinate system and the rotating coordinate system.

[0069] Specifically, if Figure 5 As shown, the three-phase current i of the permanent magnet synchronous motor is sampled. u 、i v 、i w , after Clark (3s / 2s) transformation and Park (2s / 2r) transformation, the response current signal i in the assumed coordinate system can be obtained q (q r axis response current), so according to q rThe response current of the axis determines the angle between the assumed coordinate system and the rotating coordinate system.

[0070] In one embodiment of the present invention, the q of the assumed coordinate system is determined according to the three-phase current signal. r When the response current of the axis is measured, the controller is configured to obtain q by Clark transformation and Park transformation of the three-phase current signal. r The response current signal of the axis.

[0071] In a specific embodiment, Figure 5 As shown, in the assumed coordinate system d r After injecting a high-frequency square wave signal into the shaft, the three-phase current i of the permanent magnet synchronous motor is sampled. u 、i v 、i w , after Clark (3s / 2s) transformation and Park (2s / 2r) transformation, the response current signal i in the assumed coordinate system can be obtained q (q r axis response current).

[0072] In one embodiment of the present invention, according to q r When the response current of the axis determines the angle between the assumed coordinate system and the rotating coordinate system, the controller is configured as follows:

[0073]

[0074]

[0075]

[0076] Among them, θ err is the angle between the assumed coordinate system and the rotated coordinate system, I q[k] is the q corresponding to the kth carrier period r The response current of the shaft, I q[k-1] is the q corresponding to the k-1th carrier period r The response current of the axis, T is the carrier period, u dh is the d of the permanent magnet synchronous motor after injecting high-frequency square wave signal r Shaft voltage, L d , L q They are the d-axis inductance and q-axis inductance of the permanent magnet synchronous motor respectively.

[0077] In a specific embodiment, the injected high-frequency square wave signal is, for example:

[0078]

[0079] Among them, u dh is d in the assumed coordinate system rThe high-frequency square wave signal injected on the axis, U is the amplitude of the high-frequency square wave signal, u qh is q in the assumed coordinate system r The high-frequency square wave signal injected on the axis. Substituting the high-frequency square wave signal into equation (6), we can get:

[0080]

[0081]

[0082]

[0083] in, is the q-axis response current of the permanent magnet synchronous motor after injecting high-frequency square wave signal, θ err is the angle between the assumed coordinate system and the rotated coordinate system, u dh is the d of the permanent magnet synchronous motor after injecting high-frequency square wave signal r Shaft voltage, L d , L q They are the d-axis inductance and q-axis inductance of the permanent magnet synchronous motor respectively.

[0084] Therefore, we can get:

[0085]

[0086]

[0087]

[0088] Among them, θ err is the angle between the assumed coordinate system and the rotated coordinate system, I q[k] is the q corresponding to the kth carrier period r The response current of the shaft, I q[k-1] is the q corresponding to the k-1th carrier period r The response current of the axis, T is the carrier period, u dh is the d of the permanent magnet synchronous motor after injecting high-frequency square wave signal r Shaft voltage, L d , L q They are the d-axis inductance and q-axis inductance of the permanent magnet synchronous motor respectively.

[0089] It should be noted that the high-frequency response current of the embodiment of the present invention is no longer calculated based on the edge of the injection signal, but based on the carrier cycle. The high-frequency response current component is obtained by subtracting the current of each carrier cycle from the current of the previous carrier cycle. To ensure the consistency of the polarity of the high-frequency response current component, the current difference between the two carrier cycles needs to be multiplied by the polarity of the injection voltage signal: (I q[k] -I q[k-1])sign(u dh ), so when calculating the angle error, the period T can use the carrier period, and does not need to change with the injection signal period, which simplifies the processing flow.

[0090] In one embodiment of the present invention, the household appliance includes at least one of an air conditioner, a washing machine, and a refrigerator.

[0091] Specifically, household appliances include: at least one of an air conditioner, a washing machine, and a refrigerator, and any of them containing a permanent magnet synchronous motor are applicable to the above control method, which will not be elaborated here.

[0092] According to an embodiment of the present invention, the household appliance comprises: a housing, a permanent magnet synchronous motor and a controller. The permanent magnet synchronous motor is arranged in the housing and is used to operate according to a DC input voltage. The controller is configured to: during the operation of the permanent magnet synchronous motor, obtain the d currently injected into the assumed coordinate system. r The period of the high-frequency square wave signal of the axis is determined. When the period of the currently injected high-frequency square wave signal ends, the period of the next injected high-frequency square wave signal is determined according to the period of the currently injected high-frequency square wave signal, and the next injected high-frequency square wave signal is injected into the d of the assumed coordinate system. r axis, and takes the next injected high-frequency square wave signal as the currently injected high-frequency square wave signal, and returns to the step of determining the period of the next injected high-frequency square wave signal, by injecting it into d r The high-frequency square wave signal with a variable frequency on the axis is used to disperse the noise amplitude of the fixed injection signal frequency at a certain frequency point, thereby reducing the injection noise and electromagnetic interference. Further, the next injected high-frequency square wave signal is injected into the assumed coordinate system d r Before the axis is on, the amplitude of the next injected high-frequency square wave signal is determined according to the period and amplitude of the currently injected high-frequency square wave signal and the period of the next injected high-frequency square wave signal, so that when the period (that is, the frequency) of the next injected high-frequency square wave signal changes continuously, the amplitude of the noise does not change, so that the amplitude of the noise is controlled, further reducing the injected noise and electromagnetic interference.

[0093] A further embodiment of the present invention also discloses a method for controlling a household appliance. Fig. 9 FIG. 1 is a flow chart of a method for controlling a household appliance according to an embodiment of the present invention. Fig. 9 As shown, a method for controlling a household appliance comprises the following steps:

[0094] Step S1: During the operation of the permanent magnet synchronous motor, obtain the d of the currently injected assumed coordinate system r The period of the high-frequency square wave signal of the axis.

[0095] Step S2: When the period of the currently injected high-frequency square wave signal ends, the period of the next injected high-frequency square wave signal is determined according to the period of the currently injected high-frequency square wave signal.

[0096] Step S3: inject the next injected high-frequency square wave signal into the assumed coordinate system. r axis, and use the next injected high-frequency square wave signal as the currently injected high-frequency square wave signal, and return to execute the step of determining the period of the next injected high-frequency square wave signal.

[0097] In one embodiment of the present invention, when determining the period of the next injected high-frequency square wave signal based on the period of the currently injected high-frequency square wave signal, it includes: fluctuating the period of the currently injected high-frequency square wave signal up or down by 2N carrier cycles as the period of the next injected high-frequency square wave signal, where N is an integer.

[0098] In one embodiment of the present invention, the next injected high-frequency square wave signal is injected into the assumed coordinate system d r Before the axis, it also includes: Get the d of the current injection assumed coordinate system r The amplitude of the high-frequency square wave signal of the axis; the amplitude of the next injected high-frequency square wave signal is determined according to the period and amplitude of the currently injected high-frequency square wave signal and the period of the next injected high-frequency square wave signal.

[0099] In one embodiment of the present invention, when determining the amplitude of the next injected high-frequency square wave signal according to the period and amplitude of the currently injected high-frequency square wave signal and the period of the next injected high-frequency square wave signal, it includes:

[0100] F 下 =F 当 *T 当 / T 下 ;

[0101] Among them, F 下 is the amplitude of the next injected high-frequency square wave signal, F 当 is the amplitude of the currently injected high-frequency square wave signal, T 当 is the period of the currently injected high-frequency square wave signal, T 下 The next cycle of the injected high-frequency square wave signal.

[0102] In one embodiment of the present invention, the following steps are included: r After a high-frequency square wave signal is injected into the shaft, the three-phase current signal of the permanent magnet synchronous motor is obtained; the angle between the assumed coordinate system and the rotating coordinate system is determined according to the three-phase current signal; and the real rotor position of the permanent magnet synchronous motor is determined according to the angle between the assumed coordinate system and the rotating coordinate system.

[0103] In one embodiment of the present invention, when determining the angle between the assumed coordinate system and the rotating coordinate system according to the three-phase current signal, the method includes: determining the angle q of the assumed coordinate system according to the three-phase current signal; r The response current of the axis; according to q r The response current of the axis determines the angle between the assumed coordinate system and the rotating coordinate system.

[0104] In one embodiment of the present invention, the q of the assumed coordinate system is determined according to the three-phase current signal. r The response current of the axis includes: the three-phase current signal is transformed by Clark and Park to obtain q r The response current signal of the axis.

[0105] In one embodiment of the present invention, according to q r The response current of the axis determines the angle between the assumed coordinate system and the rotating coordinate system, including:

[0106]

[0107]

[0108]

[0109] Among them, θ err is the angle between the assumed coordinate system and the rotated coordinate system, I q[k] is the q corresponding to the kth carrier period r The response current of the shaft, I q[k-1] is the q corresponding to the k-1th carrier period r The response current of the shaft, T is the carrier period, u dh is the d of the permanent magnet synchronous motor after injecting high-frequency square wave signal r Shaft voltage, L d , L q They are the d-axis inductance and q-axis inductance of the permanent magnet synchronous motor respectively.

[0110] In one embodiment of the present invention, when determining the true rotor position of a permanent magnet synchronous motor based on the angle between the assumed coordinate system and the rotating coordinate system, it includes: using a phase-locked loop to adjust the angle between the assumed coordinate system and the rotating coordinate system; when the angle between the assumed coordinate system and the rotating coordinate system is zero, the true rotor position of the permanent magnet synchronous motor is obtained.

[0111] 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 household appliance part for details. In order to reduce redundancy, it will not be repeated here.

[0112] According to the control method of the household appliance of the embodiment of the present invention, during the operation of the permanent magnet synchronous motor, the d currently injected into the assumed coordinate system is obtained. r The period of the high-frequency square wave signal of the axis is determined. When the period of the currently injected high-frequency square wave signal ends, the period of the next injected high-frequency square wave signal is determined according to the period of the currently injected high-frequency square wave signal, and the next injected high-frequency square wave signal is injected into the d of the assumed coordinate system. r axis, and takes the next injected high-frequency square wave signal as the currently injected high-frequency square wave signal, and returns to the step of determining the period of the next injected high-frequency square wave signal, by injecting it into d r The high-frequency square wave signal with a variable frequency on the axis is used to disperse the noise amplitude of the fixed injection signal frequency at a certain frequency point, thereby reducing the injection noise and electromagnetic interference. Further, the next injected high-frequency square wave signal is injected into the assumed coordinate system d r Before the axis is on, the amplitude of the next injected high-frequency square wave signal is determined according to the period and amplitude of the currently injected high-frequency square wave signal and the period of the next injected high-frequency square wave signal, so that when the period (that is, the frequency) of the next injected high-frequency square wave signal changes continuously, the amplitude of the noise does not change, so that the amplitude of the noise is controlled, further reducing the injected noise and electromagnetic interference.

[0113] 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.

[0114] 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 permanent magnet synchronous motor, disposed in the housing and configured to operate according to a DC input voltage; The controller is configured to: during the operation of the permanent magnet synchronous motor, obtain the d currently injected into the assumed coordinate system r The period of the high-frequency square wave signal of the axis; When the period of the currently injected high-frequency square wave signal ends, determining the period of the next injected high-frequency square wave signal according to the period of the currently injected high-frequency square wave signal; The next injected high-frequency square wave signal is injected into the assumed coordinate system d r axis, and use the next injected high-frequency square wave signal as the currently injected high-frequency square wave signal, and return to execute the step of determining the period of the next injected high-frequency square wave signal.

2. The household appliance according to claim 1, characterized in that: When determining the period of the next injected high-frequency square wave signal according to the period of the currently injected high-frequency square wave signal, the controller is configured as follows: The period of the currently injected high-frequency square wave signal is fluctuated upward or downward by 2N carrier cycles and then used as the period of the next injected high-frequency square wave signal, wherein N is an integer.

3. The household appliance according to claim 2, characterized in that: The next injected high-frequency square wave signal is injected into the assumed coordinate system d r Before the axis, the controller is also configured as: Get the coordinate system of the current injection assumption r The amplitude of the high-frequency square wave signal of the axis; The amplitude of the next injected high-frequency square wave signal is determined according to the period and amplitude of the currently injected high-frequency square wave signal and the period of the next injected high-frequency square wave signal.

4. The household appliance according to claim 3, characterized in that: When determining the amplitude of the next injected high-frequency square wave signal according to the period and amplitude of the currently injected high-frequency square wave signal and the period of the next injected high-frequency square wave signal, the controller is configured to execute the following formula: F 下 =F 当 *T 当 / T 下 ; Among them, F 下 is the amplitude of the next injected high-frequency square wave signal, F 当 is the amplitude of the currently injected high-frequency square wave signal, T 当 is the period of the high-frequency square wave signal injected currently, T 下 The next injected high frequency square wave signal period.

5. The household appliance according to claim 1, characterized in that: The controller is also configured to: In the assumed coordinate system d r After injecting the high-frequency square wave signal onto the shaft, obtaining the three-phase current signal of the permanent magnet synchronous motor; Determine the angle between the assumed coordinate system and the rotating coordinate system according to the three-phase current signal; The actual rotor position of the permanent magnet synchronous motor is determined according to the angle between the assumed coordinate system and the rotating coordinate system.

6. The household appliance according to claim 5, characterized in that: When determining the angle between the assumed coordinate system and the rotating coordinate system according to the three-phase current signal, the controller is configured as follows: Determine the q of the assumed coordinate system according to the three-phase current signal r The response current of the axis; According to the q r The response current of the shaft determines the angle between the assumed coordinate system and the rotating coordinate system.

7. The household appliance according to claim 6, characterized in that: Determine the q of the assumed coordinate system according to the three-phase current signal r axis response current, the controller is configured as: The three-phase current signal is transformed by Clark and Park to obtain the q r The response current signal of the axis.

8. The household appliance according to claim 6, characterized in that: According to the q r When the angle between the assumed coordinate system and the rotating coordinate system is determined by the response current of the axis, the controller is configured as follows: Among them, θ err is the angle between the assumed coordinate system and the rotated coordinate system, I q[k] is the q corresponding to the kth carrier period r The response current of the shaft, I q[k-1] is the q corresponding to the k-1th carrier period r The response current of the axis, T is the carrier period, u dh is the d of the permanent magnet synchronous motor after the high frequency square wave signal is injected r Shaft voltage, L d , L q are the d-axis inductance and q-axis inductance of the permanent magnet synchronous motor respectively.

9. The position sensorless control method of a permanent magnet synchronous motor according to claim 5, characterized in that: When determining the true rotor position of the permanent magnet synchronous motor according to the angle between the assumed coordinate system and the rotating coordinate system, the controller is configured as follows: Using a phase-locked loop to adjust the angle between the assumed coordinate system and the rotating coordinate system; When the angle between the assumed coordinate system and the rotating coordinate system is zero, the true rotor position of the permanent magnet synchronous motor is obtained.

10. A method for controlling a household appliance, characterized in that: include: During the operation of the permanent magnet synchronous motor, obtain the d r The period of the high-frequency square wave signal of the axis; When the period of the currently injected high-frequency square wave signal ends, determining the period of the next injected high-frequency square wave signal according to the period of the currently injected high-frequency square wave signal; The next injected high-frequency square wave signal is injected into the assumed coordinate system d r axis, and use the next injected high-frequency square wave signal as the currently injected high-frequency square wave signal, and return to execute the step of determining the period of the next injected high-frequency square wave signal.

Images