Household appliance and control method thereof

Abstract

The invention discloses a household appliance and a control method thereof.The household appliance comprises a shell, a permanent magnet synchronous motor and a controller, and the controller is configured to obtain the period range where the period of a high-frequency square wave signal is located in the operation process of the permanent magnet synchronous motor; injecting a high-frequency square wave signal of any period in the period range on a dr axis of the assumed coordinate system, and obtaining a three-phase current signal of the permanent magnet synchronous motor; when the period of the currently injected high-frequency square wave signal is finished, determining the period of the next injected high-frequency square wave signal according to the period range and the three-phase current signal; injecting a high-frequency square wave signal corresponding to the next period of injecting the high-frequency square wave signal into the dr axis of the assumed coordinate system, so that the next period of injecting the high-frequency square wave signal is still in the period range; the noise amplitude of the fixed injection signal frequency at a certain frequency point is dispersed through the high-frequency square wave signal with the random change frequency 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 used to operate according to a DC input voltage; and a controller, configured to: during the operation of the permanent magnet synchronous motor, obtain a period range of a high-frequency square wave signal; and in the assumed coordinate system d r The high-frequency square wave signal of any period in the period range is injected into the axis, and the three-phase current signal of the permanent magnet synchronous motor is obtained; 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 range and the three-phase current signal; the high-frequency square wave signal corresponding to the period of the next injected high-frequency square wave signal is injected into the d of the assumed coordinate system. r axis so that the period of the next injected high-frequency square wave signal is still within the period range.

[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 next cycle of the injected high-frequency square wave signal according to the cycle range and 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 Axis or d r The response current; according to the q r Axis or d r The response current and the cycle range determine the cycle of the next injected high frequency square wave signal.

[0007] Further, according to the qr Axis or d r When the response current and the cycle range determine the cycle of the next injected high-frequency square wave signal, the controller is configured to: determine the center cycle and the fluctuation cycle corresponding to the cycle range; determine whether the center cycle and the fluctuation cycle are even numbers; when it is determined that the center cycle and the fluctuation cycle are even numbers, according to the q r Axis or d r The response current, the period range, the center period and the fluctuation period determine the period of the next injected high-frequency square wave signal; when it is determined that at least one of the center period and the fluctuation period is not an even number, according to the q r Axis or d r The response current and the period range determine the period of the next injected high-frequency square wave signal.

[0008] Further, according to the q r Axis or d r When determining the period of the next injected high-frequency square wave signal based on the response current, the period range, the center period and the fluctuation period, the controller is configured to execute the following formula:

[0009] T 11 =I%(T 上 -T 下 +1)-T1+T 中 ;

[0010] Among them, T 11 is the period of the next high-frequency square wave signal injection, I is the q r Axis or d r The response current, T 上 is the upper limit of the cycle range, T 下 is the lower limit of the period range, T1 is the fluctuation period, T 中 is the central period.

[0011] Further, according to the q r Axis or d r When the response current and the cycle range determine the cycle of the next injected high-frequency square wave signal, the controller is configured to execute the following formula:

[0012] T 12 =T 上 -I%(T 上 -T 下 +1);

[0013] Among them, T 12 is the period of the next high-frequency square wave signal injection, I is the q r Axis or dr The response current, T 上 is the upper limit of the cycle range, T 下 is the lower limit of the period range.

[0014] Further, according to the q r Axis or d r When the response current and the cycle range determine the cycle of the next injected high-frequency square wave signal, the controller is configured to execute the following formula:

[0015] T 13 =T 下 +I%(T 上 -T 下 +1);

[0016] Among them, T 13 is the period of the next high-frequency square wave signal injection, I is the q r Axis or d r The response current, T 上 is the upper limit of the cycle range, T 下 is the lower limit of the period range.

[0017] Furthermore, the controller is also configured to: determine the angle between the assumed coordinate system and the rotating coordinate system according to the three-phase current signal; and determine the actual rotor position of the permanent magnet synchronous motor according to the angle between the assumed coordinate system and the rotating coordinate system.

[0018] Further, the angle between the assumed coordinate system and the rotating coordinate system is determined according to the three-phase current signal, and 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.

[0019] Further, 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 the q r The response current signal of the axis.

[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 period range of the high-frequency square wave signal, and assume that the coordinate system is d rA high-frequency square wave signal of any period in the period range is injected into the axis, and the three-phase current signal of the permanent magnet synchronous motor is obtained. 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 range and the three-phase current signal, and the high-frequency square wave signal corresponding to the period of the next injected high-frequency square wave signal is injected into the d of the assumed coordinate system. r axis, so that the next cycle of the injected high-frequency square wave signal is still within the cycle range, by injecting it into d r A high-frequency square wave signal with randomly 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.

[0021] In view of the above problems, the present invention further proposes a control method for household appliances, comprising: obtaining a period range of a high-frequency square wave signal; assuming that the coordinate system is d r The high-frequency square wave signal of any period in the period range is injected into the axis, and the three-phase current signal of the permanent magnet synchronous motor is obtained; 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 range and the three-phase current signal; the high-frequency square wave signal corresponding to the period of the next injected high-frequency square wave signal is injected into the d of the assumed coordinate system. r axis so that the period of the next injected high-frequency square wave signal is still within the period range.

[0022] According to the control method of the household appliance of the embodiment of the present invention, by obtaining the period range of the period of the high-frequency square wave signal, in the assumed coordinate system d r A high-frequency square wave signal of any period in the period range is injected into the axis, and the three-phase current signal of the permanent magnet synchronous motor is obtained. 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 range and the three-phase current signal, and the high-frequency square wave signal corresponding to the period of the next injected high-frequency square wave signal is injected into the d of the assumed coordinate system. r axis, so that the next cycle of the injected high-frequency square wave signal is still within the cycle range, by injecting it into d r A high-frequency square wave signal with randomly 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.

[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 of determining the next cycle of an injected high-frequency square wave signal according to a cycle range and a three-phase current signal according to an embodiment of the present invention;

[0028] Figure 4 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;

[0029] Figure 5 According to one embodiment of the present invention, r Axis or d r A flow chart of determining the next cycle of the injected high-frequency square wave signal based on the response current and cycle range;

[0030] Figure 6 is a flow chart of determining the true rotor position of a permanent magnet synchronous motor according to a three-phase current signal according to an embodiment of the present invention;

[0031] Figure 7 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;

[0032] Figure 8 is a flow chart of a method for controlling a household appliance according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] Reference below Figure 1-Figure 8 A home appliance and a control method thereof according to an embodiment of the present invention are described.

[0038] Figure 1 FIG. 1 is a 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 period range of the high-frequency square wave signal; in the assumed coordinate system d r A high-frequency square wave signal of any period in the period range is injected into the axis, and the three-phase current signal of the permanent magnet synchronous motor 20 is obtained; 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 range and the three-phase current signal; the high-frequency square wave signal corresponding to the period of the next injected high-frequency square wave signal is injected into the d r axis so that the next cycle of the injected high-frequency square wave signal is still within the cycle range.

[0039] Specifically, the period range of the high-frequency square wave signal can be preset in advance and stored in the controller 30. Figure 2 As shown, assuming the coordinate system is d r q 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 the d-axis direction rotated 90° counterclockwise. r After a high-frequency square wave signal of any period in the period range is injected into the axis, a three-phase current signal of the permanent magnet synchronous motor 20 is obtained. The three-phase current signal is an analog signal and will be interfered by noise during transmission, amplification and AD conversion. The converted digital signal will produce completely randomly changing data in the low position due to the influence of noise. Therefore, the embodiment of the present invention uses the data to determine the frequency of the next injected high-frequency square wave signal at the end of the current injected high-frequency square wave signal period, so that the frequency of the injected high-frequency square wave signal is a completely random frequency, and the period of the high-frequency square wave signal corresponding to the completely random frequency is still within the preset period range, that is, at the end of the current injected high-frequency square wave signal period, the period of the next injected high-frequency square wave signal is determined according to the period range and the three-phase current signal, and the high-frequency square wave signal corresponding to the next injected high-frequency square wave signal period is injected into the assumed coordinate system d r axis, so that the injection into d r The frequency of the high-frequency square wave signal on the axis is no longer a fixed value, but a random value within a certain range, which is determined by the sampled three-phase current signal. Therefore, 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 inject r A high-frequency square wave signal with randomly 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.

[0040] In one embodiment of the present invention, Figure 3 As shown, when determining the next cycle of the injected high-frequency square wave signal according to the cycle range and 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 Axis or d r The response current according to q r Axis or d r The response current and cycle range determine the next cycle of the injected high-frequency square wave signal.

[0041] In a specific embodiment, Figure 4 As shown, in the assumed coordinate system d r After injecting a high-frequency square wave signal of any period in the period range 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) and i d (d r axis response current), so according to q r Axis or d r The response current and cycle range determine the next cycle of the injected high-frequency square wave signal.

[0042] In one embodiment of the present invention, Figure 5 As shown, according to q r Axis or d r When the response current and the cycle range determine the next cycle of the high-frequency square wave signal to be injected, the controller is configured to: determine the center cycle and the fluctuation cycle corresponding to the cycle range; determine whether the center cycle and the fluctuation cycle are even numbers; when it is determined that the center cycle and the fluctuation cycle are even numbers, according to q r Axis or d r The response current, cycle range, center cycle and fluctuation cycle determine the cycle of the next injected high-frequency square wave signal; when it is determined that at least one of the center cycle and the fluctuation cycle is not an even number, according to q r Axis or d r The response current and cycle range determine the next cycle of the injected high-frequency square wave signal.

[0043] Specifically, the embodiment of the present invention injects into d r The period of the high-frequency square wave signal on the axis is an even multiple of the carrier period. Therefore, when the upper and lower limits of the period range are also even multiples of the carrier period, the period range can be composed of the center period and the fluctuation period. For example, if the carrier period is T, and the period range is 24T to 40T, then the center period corresponding to the period range is 32T, and the fluctuation period is 8T, that is, the period range can be expressed as 32T±8T. At this time, the center period and the fluctuation period are both even numbers. According to q r Axis or d r The response current, cycle range, center cycle and fluctuation cycle determine the cycle of the next injected high-frequency square wave signal. r Axis or d r When determining the next cycle of the injected high-frequency square wave signal based on the response current, cycle range, center cycle, and fluctuation cycle, the controller is configured to perform the following calculation:

[0044] T 11 =I%(T 上 -T 下 +1)-T1+T中 ;

[0045] Among them, T 11 For the next cycle of injecting high-frequency square wave signal, I is q r Axis or d r The response current, T 上 is the upper limit of the cycle range, T 下 is the lower limit of the cycle range, T1 is the fluctuation period, T 中 The center cycle.

[0046] In a specific embodiment, the carrier period is T, the period range is 24T to 40T, the center period is 32T, and the fluctuation period is 8T. r The period of the high-frequency square wave signal on the axis appears randomly between 24T and 40T. The implementation method is to replace the sampled q r Axis or d r The response current modulo 17, then subtract 8, and then add it to 32 to get the next cycle of the injected high-frequency square wave signal. As long as each cycle is calculated according to this method, a random cycle of the injected high-frequency square wave signal between 24T and 40T can be obtained, that is, by injecting it into d r A high-frequency square wave signal with randomly 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.

[0047] In one embodiment of the present invention, according to q r Axis or d r When the response current and cycle range determine the next cycle of the injected high-frequency square wave signal, the controller is configured to perform the following calculation:

[0048] T 12 =T 上 -I%(T 上 -T 下 +1);

[0049] Among them, T 12 For the next cycle of injecting high-frequency square wave signal, I is q r Axis or d r The response current, T 上 is the upper limit of the cycle range, T 下 is the lower limit of the period range.

[0050] Specifically, when the period range cannot be represented by the central period and the fluctuation period, that is, when at least one of the central period and the fluctuation period is not an even number, the embodiment of the present invention uses q r Axis or d rThe response current and cycle range determine the cycle of the next injected high-frequency square wave signal. r Axis or d r The response current is modulo the cycle range to obtain the remainder, and then the difference between the upper limit of the cycle range and the remainder is used as the cycle of the next injected high-frequency square wave signal, so that the next injected high-frequency square wave signal is still within the cycle range. In a specific embodiment, the carrier cycle is T, the cycle range is 25T ~ 40T, then the center cycle and the fluctuation cycle are not even numbers, if you want to make the injection into d r The period of the high-frequency square wave signal on the axis appears randomly between 25T and 40T. The implementation method is to replace the sampled q r Axis or d r The response current modulo 16 is obtained, and the difference between 40 and the remainder is used as the next cycle of the injected high-frequency square wave signal. As long as each cycle is calculated according to this method, a random cycle of the injected high-frequency square wave signal between 25T and 40T can be obtained, that is, by injecting into d r A high-frequency square wave signal with randomly 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.

[0051] In one embodiment of the present invention, according to q r Axis or d r When the response current and cycle range determine the next cycle of the injected high-frequency square wave signal, the controller is configured to perform the following calculation:

[0052] T 13 =T 下 +I%(T 上 -T 下 +1);

[0053] Among them, T 13 For the next cycle of injecting high-frequency square wave signal, I is q r Axis or d r The response current, T 上 is the upper limit of the cycle range, T 下 is the lower limit of the period range.

[0054] Specifically, when the period range cannot be represented by the central period and the fluctuation period, that is, when at least one of the central period and the fluctuation period is not an even number, compared with the previous embodiment, the embodiment of the present invention is based on q r Axis or d r When the response current and cycle range are used to determine the next cycle of the injected high-frequency square wave signal, another form is adopted. r Axis or d rThe response current is modulo the cycle range to obtain the remainder, and then the sum of the lower limit of the cycle range and the remainder is used as the cycle of the next injected high-frequency square wave signal, so that the next injected high-frequency square wave signal is still within the cycle range. For example, the carrier cycle is T, the cycle range is 25T ~ 40T, then the center cycle and the fluctuation cycle are not even numbers, if you want to inject into d r The period of the high-frequency square wave signal on the axis appears randomly between 25T and 40T. The implementation method is to replace the sampled q r Axis or d r The response current modulo 16 is obtained, and the sum of 25 and the remainder is used as the next cycle of the injected high-frequency square wave signal. As long as each cycle is calculated according to this method, a random cycle of the injected high-frequency square wave signal between 25T and 40T can be obtained, that is, by injecting into d r A high-frequency square wave signal with randomly 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.

[0055] In one embodiment of the present invention, Figure 6 As shown, the controller is further configured to: determine the angle between the assumed coordinate system and the rotating coordinate system according to the three-phase current signal; and determine the actual rotor position of the permanent magnet synchronous motor according to the angle between the assumed coordinate system and the rotating coordinate system.

[0056] 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:

[0057]

[0058]

[0059] 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.

[0060] 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:

[0061]

[0062]

[0063] 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.

[0064] Then transform the above equation from the rotated coordinate system to the assumed coordinate system, and we can get:

[0065]

[0066]

[0067]

[0068]

[0069] 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, 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.

[0070] 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. errWhen it approaches 0, the real rotor position of the permanent magnet synchronous motor can be obtained.

[0071] Specifically, according to the angle θ between the assumed coordinate system and the rotated 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 4 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.

[0072] In one embodiment of the present invention, Figure 7 As shown, the angle between the assumed coordinate system and the rotating coordinate system is determined according to the three-phase current signal, and 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.

[0073] Specifically, if Figure 4 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 r The response current of the axis determines the angle between the assumed coordinate system and the rotating coordinate system.

[0074] 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:

[0075]

[0076]

[0077]

[0078] Among them, θ erris 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.

[0079] In a specific embodiment, the injected high-frequency square wave signal is, for example:

[0080]

[0081] Among them, u dh is d in the assumed coordinate system r The 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:

[0082]

[0083]

[0084]

[0085] Among them, I qh 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.

[0086] Therefore, we can get:

[0087]

[0088]

[0089]

[0090] 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.

[0091] 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.

[0092] 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.

[0093] In a specific embodiment, Figure 4 As shown, in the assumed coordinate system d r After injecting a high-frequency square wave signal of any period in the period range 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).

[0094] In one embodiment of the present invention, the household appliance includes at least one of an air conditioner, a washing machine, and a refrigerator.

[0095] Specifically, household appliances include: at least one of an air conditioner, a washing machine, and a refrigerator, and the permanent magnet synchronous motor included therein can be applied to the above control method, that is, the frequency of the next injected high-frequency square wave signal is determined by using the period range and the three-phase current signal at the end of the period of the currently injected high-frequency square wave signal, so that the frequency of the injected high-frequency square wave signal is a completely random frequency, and the period of the high-frequency square wave signal corresponding to the completely random frequency is still within the preset period range, that is, 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 range and the three-phase current signal, and the high-frequency square wave signal corresponding to the period of the next injected high-frequency square wave signal is injected into the assumed coordinate system d r axis, so that the injection into d r The frequency of the high-frequency square wave signal on the axis is no longer a fixed value, but a random value within a certain range, which is determined by the sampled three-phase current signal. Therefore, compared with the noise amplitude at a certain frequency point generated by injecting a fixed-frequency high-frequency square wave signal, the noise amplitude at a certain frequency point can be increased by injecting a fixed-frequency high-frequency square wave signal into the d r A high-frequency square wave signal with randomly 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.

[0096] 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 period range of the high-frequency square wave signal, and assume that the coordinate system is d r A high-frequency square wave signal of any period in the period range is injected into the axis, and the three-phase current signal of the permanent magnet synchronous motor is obtained. 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 range and the three-phase current signal, and the high-frequency square wave signal corresponding to the period of the next injected high-frequency square wave signal is injected into the d of the assumed coordinate system. r axis, so that the next cycle of the injected high-frequency square wave signal is still within the cycle range, by injecting it into d r A high-frequency square wave signal with randomly 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.

[0097] A further embodiment of the present invention also discloses a method for controlling a household appliance. Figure 8 FIG. 1 is a flow chart of a method for controlling a household appliance according to an embodiment of the present invention. Figure 8 As shown, a method for controlling a household appliance comprises the following steps:

[0098] Step S1: Obtain the period range of the high-frequency square wave signal.

[0099] Step S2: In the assumed coordinate system d r A high-frequency square wave signal of any period in the period range is injected into the shaft, and the three-phase current signal of the permanent magnet synchronous motor is obtained.

[0100] Step S3: When the cycle of the currently injected high-frequency square wave signal ends, determine the cycle of the next injected high-frequency square wave signal according to the cycle range and the three-phase current signal.

[0101] Step S4: inject the high-frequency square wave signal corresponding to the next period of the high-frequency square wave signal into the assumed coordinate system. r axis so that the next cycle of the injected high-frequency square wave signal is still within the cycle range.

[0102] In one embodiment of the present invention, when determining the next cycle of the injected high-frequency square wave signal according to the cycle range and 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 Axis or d r The response current according to q r Axis or d r The response current and cycle range determine the next cycle of the injected high-frequency square wave signal.

[0103] In one embodiment of the present invention, according to q r Axis or d r When the response current and the cycle range determine the next cycle of the high-frequency square wave signal to be injected, the controller is configured to: determine the center cycle and the fluctuation cycle corresponding to the cycle range; determine whether the center cycle and the fluctuation cycle are even numbers; when it is determined that the center cycle and the fluctuation cycle are even numbers, according to q r Axis or d r The response current, cycle range, center cycle and fluctuation cycle determine the cycle of the next injected high-frequency square wave signal; when it is determined that at least one of the center cycle and the fluctuation cycle is not an even number, according to q r Axis or d r The response current and cycle range determine the next cycle of the injected high-frequency square wave signal.

[0104] In one embodiment of the present invention, according to q r Axis or d r When determining the next cycle of the injected high-frequency square wave signal based on the response current, cycle range, center cycle, and fluctuation cycle, the controller is configured to perform the following calculation:

[0105] T 11 =I%(T 上 -T 下 +1)-T1+T 中 ;

[0106] Among them, T 11 For the next cycle of injecting high-frequency square wave signal, I is q r Axis or d r The response current, T 上 is the upper limit of the cycle range, T 下 is the lower limit of the cycle range, T1 is the fluctuation period, T 中 The center cycle.

[0107] In one embodiment of the present invention, according to q r Axis or d r When the response current and cycle range determine the next cycle of the injected high-frequency square wave signal, the controller is configured to perform the following calculation:

[0108] T 12 =T 上 -I%(T 上 -T 下 +1);

[0109] Among them, T 12 For the next cycle of injecting high-frequency square wave signal, I is q r Axis or d r The response current, T 上 is the upper limit of the cycle range, T 下 is the lower limit of the period range.

[0110] In one embodiment of the present invention, according to q r Axis or d r When the response current and cycle range determine the next cycle of the injected high-frequency square wave signal, the controller is configured to perform the following calculation:

[0111] T 13 =T 下 +I%(T 上 -T 下 +1);

[0112] Among them, T 13 For the next cycle of injecting high-frequency square wave signal, I is q r Axis or d r The response current, T 上 is the upper limit of the cycle range, T 下 is the lower limit of the period range.

[0113] In one embodiment of the present invention, the controller is further configured to: determine the angle between the assumed coordinate system and the rotating coordinate system according to the three-phase current signal; and determine the actual rotor position of the permanent magnet synchronous motor according to the angle between the assumed coordinate system and the rotating coordinate system.

[0114] In one embodiment of the present invention, the angle between the assumed coordinate system and the rotating coordinate system is determined according to the three-phase current signal, and the controller is configured to: determine 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.

[0115] 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 of the axis responds to the current signal.

[0116] 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 method part for details. In order to reduce redundancy, it will not be repeated here.

[0117] According to the control method of the household appliance of the embodiment of the present invention, by obtaining the period range of the period of the high-frequency square wave signal, in the assumed coordinate system d r A high-frequency square wave signal of any period in the period range is injected into the axis, and the three-phase current signal of the permanent magnet synchronous motor is obtained. 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 range and the three-phase current signal, and the high-frequency square wave signal corresponding to the period of the next injected high-frequency square wave signal is injected into the d of the assumed coordinate system. r axis, so that the next cycle of the injected high-frequency square wave signal is still within the cycle range, by injecting it into d r A high-frequency square wave signal with randomly 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.

[0118] 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.

[0119] 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 a period range of the period of the high-frequency square wave signal; In the assumed coordinate system d r Injecting the high-frequency square wave signal of any period in the period range onto the shaft, and acquiring the three-phase current signal of the permanent magnet synchronous motor; At the end of the cycle of the currently injected high-frequency square wave signal, determining the cycle of the next injected high-frequency square wave signal according to the cycle range and the three-phase current signal; The high-frequency square wave signal corresponding to the next period of the high-frequency square wave signal is injected into the assumed coordinate system. r axis so that the period of the next injected high-frequency square wave signal is still within the period range.

2. The household appliance according to claim 1, characterized in that: When determining the next cycle of the injected high-frequency square wave signal according to the cycle range and 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 Axis or d r The response current; According to the q r Axis or d r The response current and the cycle range determine the cycle of the next injected high frequency square wave signal.

3. The household appliance according to claim 2, characterized in that: According to the q r Axis or d r When the response current and the cycle range determine the cycle of the next injected high-frequency square wave signal, the controller is configured to: Determine the central period and the fluctuation period corresponding to the period range; Determining whether the center period and the fluctuation period are even numbers; When it is determined that the central period and the fluctuation period are even numbers, according to the q r Axis or d r The response current, the period range, the center period and the fluctuation period determine the period of the next injected high-frequency square wave signal; When it is determined that at least one of the central period and the fluctuation period is not an even number, according to the q r Axis or d r The response current and the period range determine the period of the next injected high-frequency square wave signal.

4. The household appliance according to claim 3, characterized in that: According to the q r Axis or d r When determining the period of the next injected high-frequency square wave signal based on the response current, the period range, the center period and the fluctuation period, the controller is configured to execute the following formula: T 11 =I%(T 上 -T 下 +1)-T1+T 中 ; Among them, T 11 is the period of the next injected high-frequency square wave signal, I is the q r Axis or d r The response current, T 上 is the upper limit of the cycle range, T 下 is the lower limit of the period range, T1 is the fluctuation period, T 中 is the central period.

5. The household appliance according to claim 3, characterized in that: According to the q r Axis or d r When the response current and the cycle range determine the cycle of the next injected high-frequency square wave signal, the controller is configured to execute the following formula: T 12 =T 上 -I%(T 上 -T 下 +1); Among them, T 12 is the period of the next high-frequency square wave signal injection, I is the q r Axis or d r The response current, T 上 is the upper limit of the cycle range, T 下 is the lower limit of the period range.

6. The household appliance according to claim 3, characterized in that: According to the q r Axis or d r When the response current and the cycle range determine the cycle of the next injected high-frequency square wave signal, the controller is configured to execute the following formula: T 13 =T 下 +I%(T 上 -T 下 +1); Among them, T 13 is the period of the next high-frequency square wave signal injection, I is the q r Axis or d r The response current, T 上 is the upper limit of the cycle range, T 下 is the lower limit of the period range.

7. The household appliance according to claim 1, characterized in that: The controller is also configured to: 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.

8. The household appliance according to claim 7, characterized in that: Determine the angle between the assumed coordinate system and the rotating coordinate system according to the three-phase current signal, and 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.

9. The household appliance according to claim 2 or 8, characterized in that: Determine the q of the assumed coordinate system 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 the q r The response current signal of the axis.

10. A method for controlling a household appliance, characterized in that: include: Get the period range of the high-frequency square wave signal; In the assumed coordinate system d r Injecting the high-frequency square wave signal of any period in the period range onto the shaft, and acquiring the three-phase current signal of the permanent magnet synchronous motor; At the end of the cycle of the currently injected high-frequency square wave signal, determining the cycle of the next injected high-frequency square wave signal according to the cycle range and the three-phase current signal; The high-frequency square wave signal corresponding to the next period of the high-frequency square wave signal is injected into the assumed coordinate system. r axis so that the period of the next injected high-frequency square wave signal is still within the period range.

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