Refrigerator and Method for Optimizing Motor Startup

Abstract

The present invention discloses a method for optimizing the startup of a refrigerator and a motor. The refrigerator includes a compressor whose driving mechanism is a motor; a controller configured to: upon receiving a startup command, control the rotation of the motor's rotor; after determining that the rotor has rotated to a positioning angle, control the motor to perform a drag start; during the drag process of the motor, detect the back electromotive force parameters and rotational speed of the motor when its rotor rotates to N preset angles; select a target angle from the N preset angles based on the relationship between the back electromotive force parameters corresponding to the N preset angles and a preset interval, and the relationship between the rotational speed corresponding to the N preset angles and a preset threshold; and correct the positioning angle to the target angle. The embodiments of the present invention can effectively solve the problem of compressor startup difficulty or inability to start.

Description

Technical Field

[0001] The present invention relates to the technical field of household appliances, and in particular to a refrigerator and a motor startup optimization method. Background Art

[0002] Currently, motors for compressors in refrigerators, air conditioners, and other appliances, as well as motors in washing machines, typically use Field-Oriented Control (FOC) for variable frequency control. FOC can precisely control the magnitude and direction of the magnetic field, resulting in smooth motor torque, low noise, high efficiency, and high-speed dynamic response. When controlling the motor's operation through FOC, the motor's startup process typically includes several stages: positioning, dragging, and closed-loop control. The motor's positioning angle during the positioning stage is typically a fixed, predetermined angle. However, when starting with a heavy load, this fixed, predetermined angle can easily lead to difficulty or even failure in starting the compressor. Summary of the Invention

[0003] The embodiment of the present invention provides a method for optimizing the startup of a refrigerator and a motor, which can effectively solve the problem that the compressor is difficult to start or cannot start.

[0004] An embodiment of the present invention provides a refrigerator, comprising:

[0005] A compressor, whose driving mechanism is an electric motor;

[0006] A controller for:

[0007] When a start command is received, controlling the rotor of the motor to rotate;

[0008] After determining that the rotor rotates to the positioning angle, controlling the motor to start the drag;

[0009] During the driving process of the motor, detecting back electromotive force parameters and rotation speed of the motor when its rotor rotates to N preset angles;

[0010] Selecting a target angle from the N preset angles based on a magnitude relationship between back electromotive force parameters corresponding to the N preset angles and a preset interval, and a magnitude relationship between rotational speeds corresponding to the N preset angles and a preset threshold;

[0011] The positioning angle is corrected to the target angle.

[0012] Compared with the prior art, the refrigerator disclosed in the embodiment of the present invention detects the back electromotive force parameters and speed of the motor when its rotor rotates to N preset angles during the dragging process of the compressor motor, and selects a target angle from the N preset angles based on the size relationship between the back electromotive force parameters corresponding to the N preset angles and the preset interval, and the size relationship between the speed corresponding to the N preset angles and the preset threshold. Then, the positioning angle of the motor in the positioning stage is corrected to the target angle, which can ensure that the motor starts at the optimal positioning angle, thereby effectively solving the problem of difficulty or inability to start the compressor.

[0013] As an improvement to the above solution, the target angle is selected from the N preset angles based on the magnitude relationship between the back electromotive force parameters corresponding to the N preset angles and the preset interval, and the magnitude relationship between the rotational speeds corresponding to the N preset angles and the preset threshold, specifically:

[0014] For the characteristic parameters at the N preset angles, if the back electromotive force parameter corresponding to a preset angle is within a preset range and / or the rotation speed corresponding to the preset angle is not lower than a preset threshold, the preset angle is determined to be the target angle.

[0015] In this embodiment, by selecting a preset angle in which the back electromotive force parameter is within a preset range and / or the speed is not lower than a preset threshold as the target angle for optimal startup, it is possible to ensure that when the motor is started at the selected positioning angle, the back electromotive force parameter and / or the speed meet the requirements, thereby achieving optimal startup.

[0016] As an improvement to the above solution, the back electromotive force parameter is the ratio of the d-axis back electromotive force to the q-axis back electromotive force of the motor;

[0017] The preset interval is 20% to 60%.

[0018] In this embodiment, the back electromotive force parameter is the ratio of the d-axis back electromotive force to the q-axis back electromotive force of the motor, and the preset interval is 20% to 60%, which can prevent the motor from being stuck during startup and unable to start normally.

[0019] As an improvement to the above solution, the back electromotive force parameters corresponding to any preset angle are obtained in the following manner:

[0020] Obtaining the stator current and stator voltage of the α-axis and the β-axis of the motor when the rotor thereof rotates to the preset angle;

[0021] Calculating the α-axis back electromotive force and the β-axis back electromotive force according to the stator current and stator voltage of the α-axis and the β-axis, and the stator resistance and stator inductance of the motor obtained in advance;

[0022] Calculating the d-axis back electromotive force and the q-axis back electromotive force according to the preset angle, the α-axis back electromotive force, and the β-axis back electromotive force;

[0023] The ratio of the d-axis back electromotive force to the q-axis back electromotive force is calculated to obtain a back electromotive force parameter corresponding to the preset angle.

[0024] In this embodiment, the stator current and stator voltage of the α-axis and β-axis of the motor are obtained when its rotor rotates to a certain preset angle, and combined with the stator resistance and stator inductance of the motor obtained in advance, the α-axis back electromotive force and the β-axis back electromotive force are calculated. Then, the α-axis back electromotive force and the β-axis back electromotive force and the preset angle are combined to calculate the d-axis back electromotive force and the q-axis back electromotive force corresponding to the preset angle, so that the back electromotive force parameters corresponding to the preset angle can be accurately calculated, thereby improving the accuracy of the optimal positioning angle.

[0025] As an improvement to the above solution, the calculation formula of the α-axis back electromotive force is:

[0026] E α =V α –R s I α –L s dI α / dt;

[0027] The calculation formula of the β-axis back electromotive force is:

[0028] E β =V β –R s I β –L s dI β / dt;

[0029] The calculation formula of the d-axis back electromotive force is:

[0030] E d =E α cos(θ esti )+E β sin(θ esti );

[0031] The calculation formula of the q-axis back electromotive force is:

[0032] E q =E β cos(θ esti )-E α sin(θ esti );

[0033] Among them, E α is the α-axis back electromotive force; E βare the β-axis back electromotive force; V α is the α-axis stator voltage of the motor; V β is the β-axis stator voltage of the motor; I α is the α-axis stator current of the motor; I β is the β-axis stator current of the motor; R s is the stator resistance of the motor; L s is the stator inductance of the motor; E d is the d-axis back electromotive force; E q is the q-axis back electromotive force; θ esti is the preset angle.

[0034] Another embodiment of the present invention provides a method for optimizing the startup of a motor, comprising:

[0035] When receiving a start command, the motor's rotor is controlled to rotate;

[0036] After determining that the rotor rotates to the positioning angle, controlling the motor to start the drag;

[0037] During the driving process of the motor, detecting back electromotive force parameters and rotation speed of the motor when its rotor rotates to N preset angles;

[0038] Selecting a target angle from the N preset angles based on a magnitude relationship between back electromotive force parameters corresponding to the N preset angles and a preset interval, and a magnitude relationship between rotational speeds corresponding to the N preset angles and a preset threshold;

[0039] The positioning angle is corrected to the target angle.

[0040] Compared with the prior art, the motor starting optimization method disclosed in the embodiment of the present invention detects the back electromotive force parameters and speed of the motor when its rotor rotates to N preset angles during the dragging process of the motor, and selects a target angle from the N preset angles based on the size relationship between the back electromotive force parameters corresponding to the N preset angles and the preset interval, and the size relationship between the speed corresponding to the N preset angles and the preset threshold. Then, the positioning angle of the motor in the positioning stage is corrected to the target angle, which can ensure that the motor starts at the optimal positioning angle, thereby effectively solving the problem of difficulty or inability to start the compressor.

[0041] As an improvement to the above solution, the target angle is selected from the N preset angles based on the magnitude relationship between the back electromotive force parameters corresponding to the N preset angles and the preset interval, and the magnitude relationship between the rotational speeds corresponding to the N preset angles and the preset threshold, specifically:

[0042] For the characteristic parameters at the N preset angles, if the back electromotive force parameter corresponding to a preset angle is within a preset range and / or the rotation speed corresponding to the preset angle is not lower than a preset threshold, the preset angle is determined to be the target angle.

[0043] In this embodiment, by selecting a preset angle in which the back electromotive force parameter is within a preset range and / or the speed is not lower than a preset threshold as the target angle for optimal startup, it is possible to ensure that when the motor is started at the selected positioning angle, the back electromotive force parameter and / or the speed meet the requirements, thereby achieving optimal startup.

[0044] As an improvement to the above solution, the back electromotive force parameter is the ratio of the d-axis back electromotive force to the q-axis back electromotive force of the motor;

[0045] The preset interval is 20% to 60%.

[0046] In this embodiment, the back electromotive force parameter is the ratio of the d-axis back electromotive force to the q-axis back electromotive force of the motor, and the preset interval is 20% to 60%, which can prevent the motor from being stuck during startup and unable to start normally.

[0047] As an improvement to the above solution, the back electromotive force parameters corresponding to any preset angle are obtained in the following manner:

[0048] Obtaining the stator current and stator voltage of the α-axis and the β-axis of the motor when the rotor thereof rotates to the preset angle;

[0049] Calculating the α-axis back electromotive force and the β-axis back electromotive force according to the stator current and stator voltage of the α-axis and the β-axis, and the stator resistance and stator inductance of the motor obtained in advance;

[0050] Calculating the d-axis back electromotive force and the q-axis back electromotive force according to the preset angle, the α-axis back electromotive force, and the β-axis back electromotive force;

[0051] The ratio of the d-axis back electromotive force to the q-axis back electromotive force is calculated to obtain a back electromotive force parameter corresponding to the preset angle.

[0052] In this embodiment, the stator current and stator voltage of the α-axis and β-axis of the motor are obtained when its rotor rotates to a certain preset angle, and combined with the stator resistance and stator inductance of the motor obtained in advance, the α-axis back electromotive force and the β-axis back electromotive force are calculated. Then, the α-axis back electromotive force and the β-axis back electromotive force and the preset angle are combined to calculate the d-axis back electromotive force and the q-axis back electromotive force corresponding to the preset angle, so that the back electromotive force parameters corresponding to the preset angle can be accurately calculated, thereby improving the accuracy of the optimal positioning angle.

[0053] As an improvement to the above solution, the calculation formula of the α-axis back electromotive force is:

[0054] E α =V α –R s I α –L s dI α / dt;

[0055] The calculation formula of the β-axis back electromotive force is:

[0056] E β =V β –R s I β –L s dI β / dt;

[0057] The calculation formula of the d-axis back electromotive force is:

[0058] E d =E α cos(θ esti )+E β sin(θ esti );

[0059] The calculation formula of the q-axis back electromotive force is:

[0060] E q =E β cos(θ esti )-E α sin(θ esti );

[0061] Among them, E α is the α-axis back electromotive force; E β are the β-axis back electromotive force; V α is the α-axis stator voltage of the motor; V β is the β-axis stator voltage of the motor; I α is the α-axis stator current of the motor; I β is the β-axis stator current of the motor; R s is the stator resistance of the motor; L s is the stator inductance of the motor; E d is the d-axis back electromotive force; E q is the q-axis back electromotive force; θ esti is the preset angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 This is a structural diagram of a refrigerator provided by one embodiment of the present invention;

[0063] Figure 2 This is a schematic diagram of the internal structure of a refrigerator provided by one embodiment of the present invention;

[0064] Figure 3 This is a structural diagram of a compressor provided by one embodiment of the present invention;

[0065] Figure 4 1 is a structural diagram of a FOC control circuit provided by one embodiment of the present invention;

[0066] Figure 5 This is a schematic diagram of a specific flow chart of a refrigerator controller provided by one embodiment of the present invention;

[0067] Figure 6 1 is a flow chart of a motor startup optimization method provided by one embodiment of the present invention;

[0068] Figure 7 It is a flow chart of a motor startup optimization method provided by another embodiment of the present invention. DETAILED DESCRIPTION

[0069] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0070] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0071] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0072] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0073] See also Figure 1 , is a structural diagram of a refrigerator provided by one embodiment of the present invention.

[0074] An embodiment of the present invention provides a refrigerator, comprising:

[0075] The compressor 100, whose driving mechanism is a motor 101;

[0076] The controller 200 is configured to:

[0077] When a start command is received, the rotor of the motor 101 is controlled to rotate;

[0078] After determining that the rotor rotates to the positioning angle, controlling the motor 101 to start dragging;

[0079] During the driving process of the motor 101, detecting the back electromotive force parameters and the speed of the motor 101 when the rotor thereof rotates to N preset angles;

[0080] Selecting a target angle from the N preset angles based on a magnitude relationship between back electromotive force parameters corresponding to the N preset angles and a preset interval, and a magnitude relationship between rotational speeds corresponding to the N preset angles and a preset threshold;

[0081] The positioning angle is corrected to the target angle.

[0082] In this embodiment, the N preset angles can be selected based on actual conditions, and N is generally greater than or equal to 3. For example, the increment angle can be 1, that is, the N preset angles are 0, 1, 2, 3, ..., 360 degrees, respectively. Alternatively, the increment angle can be 30, that is, the N preset angles are 0, 30, 60, ..., 360 degrees, respectively. This is not limited here, and N is greater than or equal to 3.

[0083] For example, see Figure 2 The compressor 100 is usually located at the bottom of the back of the refrigerator, with the outer shell fixed to the bottom plate and connected to the refrigerator refrigeration pipeline through two pipe openings.

[0084] In a specific embodiment, the refrigerator provided by the embodiment of the present invention may also include a condenser, an anti-condensation tube, a drying filter, a capillary tube, an evaporator and a gas-liquid separator. The refrigeration working process of the refrigerator provided by this embodiment includes a compression process, a condensation process, a throttling process and an evaporation process. Among them, the compression process is: plug in the power cord of the refrigerator, when the contacts of the thermostat are connected, the compressor 100 starts to work, the low-temperature, low-pressure refrigerant is sucked into the compressor 100, and is compressed into a high-temperature, high-pressure superheated gas in the cylinder of the compressor 100 and then discharged into the condenser; the condensation process is: the high-temperature, high-pressure refrigerant gas dissipates heat through the condenser, the temperature continues to drop, and is gradually cooled to a saturated vapor of normal temperature and high pressure, and is further cooled to a saturated liquid, and the temperature no longer drops. The temperature at this time is called the condensation temperature, and the pressure of the refrigerant remains almost unchanged during the entire condensation process. ; The throttling process is as follows: the saturated liquid refrigerant after condensation is filtered out of moisture and impurities by the drying filter and then flows into the capillary tube, through which throttling and pressure reduction are performed, and the refrigerant becomes wet steam at room temperature and low pressure; the evaporation process is as follows: the wet steam at room temperature and low pressure begins to absorb heat and vaporize in the evaporator, which not only reduces the temperature of the evaporator and its surroundings, but also turns the refrigerant into a low-temperature, low-pressure gas. The refrigerant coming out of the evaporator passes through the gas-liquid separator and returns to the compressor 100 again, repeating the above process to transfer the heat in the refrigerator to the air outside the box, thereby achieving the purpose of refrigeration.

[0085] For example, the compressor 100 of the refrigerator provided in this embodiment is a reciprocating compressor 100, such as Figure 3 As shown, it includes: motor 101, crankshaft 5, connecting rod 4, piston 2, slider 3, cylinder 1, intake valve 6, and exhaust valve 7. After motor 101 is started, it drives crankshaft 5, which in turn drives connecting rod 4, which in turn drives piston 2, causing piston 2 to move up and down. The movement of piston 2 causes the volume within cylinder 1 to change. When piston 2 moves downward, the volume of cylinder 1 increases, intake valve 6 opens, and exhaust valve 7 closes, allowing air to be drawn in, completing the intake process. When piston 2 moves upward, the volume of cylinder 1 decreases, exhaust valve 7 opens, and intake valve 6 closes, completing the compression process.

[0086] It should be noted that if the speed of the motor 101 is too low, the compressor 100 cannot start normally, and the compressor 100 will vibrate significantly when the motor 101 is running at a low speed. Therefore, in this embodiment, by determining the relationship between the speeds corresponding to the N preset angles and the preset threshold, the optimal target angle for startup is selected. This not only ensures smooth startup of the compressor 100, but also reduces vibration of the compressor 100. In this embodiment, the preset threshold can be set based on the minimum speed of the motor 101 in the compressor 100 specification parameters, which is not limited here.

[0087] It should be noted that back EMF refers to the electromotive force generated by opposing the tendency of current to change. When motor 101 is initially started, the excitation winding establishes a magnetic field, and the armature current generates another magnetic field. The two magnetic fields interact, starting motor 101 and causing the armature winding to rotate in the magnetic field, thus producing a generator effect. In fact, the rotating armature generates an induced electromotive force with the opposite polarity of the armature voltage. This self-induced electromotive force is called back EMF. Back EMF consumes electrical energy in the circuit. When the back EMF parameter is too large, the power cannot meet the normal operation requirements of the load, and stalling is likely to occur. Therefore, in this embodiment, by determining the relationship between the back EMF parameters corresponding to the N preset angles and the preset interval, the optimal target starting angle is selected. This can prevent motor 101 from stalling, thereby ensuring smooth startup of compressor 100. In this embodiment, the preset interval can be set according to the stall determination value of motor 101, which is not limited here.

[0088] Compared with the prior art, the refrigerator disclosed in the embodiment of the present invention detects the back electromotive force parameters and speed of the motor 101 when its rotor rotates to N preset angles during the dragging process of the motor 101 of the compressor 100, and selects a target angle from the N preset angles based on the size relationship between the back electromotive force parameters corresponding to the N preset angles and the preset interval, and the size relationship between the speed corresponding to the N preset angles and the preset threshold. Then, the positioning angle of the motor 101 in the positioning stage is corrected to the target angle, which can ensure that the motor 101 starts at the optimal positioning angle, thereby effectively solving the problem of difficulty or inability to start the compressor 100, and can also achieve the effect of positioning startup with a smaller current, thereby reducing the impact noise during startup and avoiding damage and carbonization of the compressor coil caused by large current positioning.

[0089] As one of the optional embodiments, the target angle is selected from the N preset angles based on the magnitude relationship between the back electromotive force parameters corresponding to the N preset angles and the preset interval, and the magnitude relationship between the rotational speeds corresponding to the N preset angles and the preset threshold, specifically:

[0090] For the characteristic parameters at the N preset angles, if the back electromotive force parameter corresponding to a preset angle is within a preset range and / or the rotation speed corresponding to the preset angle is not lower than a preset threshold, the preset angle is determined to be the target angle.

[0091] In this embodiment, by selecting a preset angle in which the back electromotive force parameter is within a preset range and / or the rotational speed is not lower than a preset threshold as the target angle for optimal startup, it is possible to ensure that when the motor 101 is started at the selected positioning angle, the back electromotive force parameter and / or the rotational speed meet the requirements, thereby achieving optimal startup.

[0092] Specifically, the back electromotive force parameter is the ratio of the d-axis back electromotive force to the q-axis back electromotive force of the motor 101;

[0093] The preset interval is 20% to 60%.

[0094] In this embodiment, the back electromotive force parameter is the ratio of the d-axis back electromotive force to the q-axis back electromotive force of the motor 101, and the preset interval is 20% to 60%, which can prevent the motor 101 from being stuck during startup and unable to start normally.

[0095] Furthermore, the back electromotive force parameters corresponding to any preset angle are obtained in the following manner:

[0096] Obtaining the stator current and stator voltage of the α-axis and the β-axis of the motor 101 when the rotor thereof rotates to the preset angle;

[0097] Calculating the α-axis back electromotive force and the β-axis back electromotive force according to the stator current and stator voltage of the α-axis and the β-axis, and the stator resistance and stator inductance of the motor 101 obtained in advance;

[0098] Calculating the d-axis back electromotive force and the q-axis back electromotive force according to the preset angle, the α-axis back electromotive force, and the β-axis back electromotive force;

[0099] The ratio of the d-axis back electromotive force to the q-axis back electromotive force is calculated to obtain a back electromotive force parameter corresponding to the preset angle.

[0100] See also Figure 4 In this embodiment, the motor 101 utilizes the FOC algorithm. The specific algorithm process is as follows: The three-phase currents Ia, Ib, and Ic flowing through the PMSM motor 101 are acquired via sampling resistor R. Clarke transforms are used to obtain Iα and Iβ, which are then converted to Iq and Id via Park transforms. Based on Iα and Iβ, an estimator estimates the actual speed ω, which is compared with the set speed. PI regulation is then used to output reference currents Iq and Id. Current loop PI regulation is then used to output actual currents Vq and Vd. After inverse Clarke and inverse Park transforms, as well as SVM modulation, a three-phase bridge is output to drive the motor 101. The FOC control algorithm has two closed loops: a current loop, including the Q-axis current loop and the D-axis current loop, and a speed loop. The current loop is the outer loop, while the speed loop is the inner loop. Both closed loops are implemented using PI regulation. The current loop regulates torque and excitation, while the speed loop regulates speed.

[0101] In this embodiment, the stator current and stator voltage of the α-axis and β-axis of the motor 101 are obtained when its rotor rotates to a certain preset angle, and combined with the stator resistance and stator inductance of the motor 101 obtained in advance, the α-axis back electromotive force and the β-axis back electromotive force are calculated, and then the α-axis back electromotive force and the β-axis back electromotive force and the preset angle are combined to calculate the d-axis back electromotive force and the q-axis back electromotive force corresponding to the preset angle, so that the back electromotive force parameters corresponding to the preset angle can be accurately calculated, thereby improving the accuracy of the optimal positioning angle.

[0102] Specifically, the calculation formula of the α-axis back electromotive force is:

[0103] E α =V α –R s I α –L s dI α / dt;

[0104] The calculation formula of the β-axis back electromotive force is:

[0105] E β =V β –R s I β –L s dI β / dt;

[0106] The calculation formula of the d-axis back electromotive force is:

[0107] E d =E α cos(θ esti )+E β sin(θ esti );

[0108] The calculation formula of the q-axis back electromotive force is:

[0109] E q =E β cos(θ esti )-E α sin(θ esti );

[0110] Among them, E α is the α-axis back electromotive force; E β are the β-axis back electromotive force; V α is the α-axis stator voltage of the motor 101; V β is the β-axis stator voltage of the motor 101; I α is the α-axis stator current of the motor 101; I β is the β-axis stator current of the motor 101; Rs is the stator resistance of the motor 101; L s is the stator inductance of the motor 101; E d is the d-axis back electromotive force; E q is the q-axis back electromotive force; θ esti is the preset angle.

[0111] See also Figure 5 The following is a specific example to illustrate the working process of the refrigerator controller 200 provided in this embodiment:

[0112] S11, upon receiving a start instruction, controlling the rotor of the motor 101 to rotate;

[0113] S12, after determining that the rotor rotates to the positioning angle, controlling the motor 101 to start dragging;

[0114] S13, during the dragging process of the motor 101, determining whether the rotor of the motor 101 rotates to one of N preset angles, if so, proceeding to step S14, if not, continuing the determination;

[0115] S14, obtaining the back electromotive force parameters and speed of the motor 101, and proceeding to step S15;

[0116] S15, determining whether the back electromotive force parameters and rotational speeds corresponding to the N preset angles have been obtained, if so, proceeding to step S16, if not, returning to step S13;

[0117] S16, selecting a target angle from the N preset angles based on a magnitude relationship between back electromotive force parameters corresponding to the N preset angles and a preset interval, and a magnitude relationship between rotational speeds corresponding to the N preset angles and a preset threshold;

[0118] S17: Correct the positioning angle to the target angle.

[0119] See also Figure 6 , is a flow chart of a motor startup optimization method provided by one embodiment of the present invention.

[0120] An embodiment of the present invention provides a method for optimizing the startup of a motor, comprising:

[0121] S21, when receiving a start command, controlling the rotor of the motor to rotate;

[0122] S22, after determining that the rotor rotates to the positioning angle, controlling the motor to start the drag;

[0123] S23, during the dragging process of the motor, detecting back electromotive force parameters and rotational speed of the motor when its rotor rotates to N preset angles;

[0124] S24, selecting a target angle from the N preset angles based on a magnitude relationship between back electromotive force parameters corresponding to the N preset angles and a preset interval, and a magnitude relationship between rotational speeds corresponding to the N preset angles and a preset threshold;

[0125] S25: Correct the positioning angle to the target angle.

[0126] Compared with the prior art, the motor starting optimization method disclosed in the embodiment of the present invention detects the back electromotive force parameters and speed of the motor when its rotor rotates to N preset angles during the dragging process of the motor, and selects a target angle from the N preset angles based on the size relationship between the back electromotive force parameters corresponding to the N preset angles and the preset interval, and the size relationship between the speed corresponding to the N preset angles and the preset threshold. Then, the positioning angle of the motor in the positioning stage is corrected to the target angle, which can ensure that the motor starts at the optimal positioning angle, thereby effectively solving the problem of difficulty or inability to start the compressor.

[0127] As an optional embodiment, see Figure 7 , the target angle is selected from the N preset angles based on the relationship between the back electromotive force parameters corresponding to the N preset angles and the preset interval, and the relationship between the rotation speeds corresponding to the N preset angles and the preset threshold, specifically:

[0128] For the characteristic parameters at the N preset angles, if the back electromotive force parameter corresponding to a preset angle is within a preset range and / or the rotation speed corresponding to the preset angle is not lower than a preset threshold, the preset angle is determined to be the target angle.

[0129] In this embodiment, by selecting a preset angle in which the back electromotive force parameter is within a preset range and / or the speed is not lower than a preset threshold as the target angle for optimal startup, it is possible to ensure that when the motor is started at the selected positioning angle, the back electromotive force parameter and / or the speed meet the requirements, thereby achieving optimal startup.

[0130] As one of the optional embodiments, the back electromotive force parameter is the ratio of the d-axis back electromotive force to the q-axis back electromotive force of the motor;

[0131] The preset interval is 20% to 60%.

[0132] In this embodiment, the back electromotive force parameter is the ratio of the d-axis back electromotive force to the q-axis back electromotive force of the motor, and the preset interval is 20% to 60%, which can prevent the motor from being stuck during startup and unable to start normally.

[0133] Furthermore, the back electromotive force parameters corresponding to any preset angle are obtained in the following manner:

[0134] Obtaining the stator current and stator voltage of the α-axis and the β-axis of the motor when the rotor thereof rotates to the preset angle;

[0135] Calculating the α-axis back electromotive force and the β-axis back electromotive force according to the stator current and stator voltage of the α-axis and the β-axis, and the stator resistance and stator inductance of the motor obtained in advance;

[0136] Calculating the d-axis back electromotive force and the q-axis back electromotive force according to the preset angle, the α-axis back electromotive force, and the β-axis back electromotive force;

[0137] The ratio of the d-axis back electromotive force to the q-axis back electromotive force is calculated to obtain a back electromotive force parameter corresponding to the preset angle.

[0138] In this embodiment, the stator current and stator voltage of the α-axis and β-axis of the motor are obtained when its rotor rotates to a certain preset angle, and combined with the stator resistance and stator inductance of the motor obtained in advance, the α-axis back electromotive force and the β-axis back electromotive force are calculated. Then, the α-axis back electromotive force and the β-axis back electromotive force and the preset angle are combined to calculate the d-axis back electromotive force and the q-axis back electromotive force corresponding to the preset angle, so that the back electromotive force parameters corresponding to the preset angle can be accurately calculated, thereby improving the accuracy of the optimal positioning angle.

[0139] Specifically, the calculation formula of the α-axis back electromotive force is:

[0140] E α =V α –R s I α –L s dI α / dt;

[0141] The calculation formula of the β-axis back electromotive force is:

[0142] E β =V β –R s I β –L s dI β / dt;

[0143] The calculation formula of the d-axis back electromotive force is:

[0144] Ed =E α cos(θ esti )+E β sin(θ esti );

[0145] The calculation formula of the q-axis back electromotive force is:

[0146] E q =E β cos(θ esti )-E α sin(θ esti );

[0147] Among them, E α is the α-axis back electromotive force; E β are the β-axis back electromotive force; V α is the α-axis stator voltage of the motor; V β is the β-axis stator voltage of the motor; I α is the α-axis stator current of the motor; I β is the β-axis stator current of the motor; R s is the stator resistance of the motor; L s is the stator inductance of the motor; E d is the d-axis back electromotive force; E q is the q-axis back electromotive force; θ esti is the preset angle.

[0148] It should be noted that the motor startup optimization method provided in this embodiment can be applied to compressor motors in household appliances such as refrigerators and air conditioners, as well as to motors in household appliances such as washing machines. Of course, it can also be applied to other devices with motors, and this is not limited here. A detailed description of the motor startup optimization method provided in this embodiment can be referenced to the above-mentioned device embodiment and will not be repeated here.

[0149] Another embodiment of the present invention further provides a controller. This controller includes a processor, a memory, and a computer program stored in the memory and executable on the processor, such as the motor startup optimization method described in the aforementioned method embodiment. When the processor executes the computer program, it implements the steps described in each of the aforementioned motor startup optimization method embodiments.

[0150] For example, the computer program may be divided into one or more modules / units, which are stored in the memory and executed by the processor to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, and the instruction segments are used to describe the execution process of the computer program in the controller.

[0151] The controller may include, but is not limited to, a processor and a memory. Those skilled in the art will appreciate that the schematic diagram is merely an example of a controller and does not limit the controller. The controller may include more or fewer components than shown, or a combination of certain components, or different components. For example, the controller may also include input and output devices, network access devices, buses, etc.

[0152] The processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc. The processor is the control center of the controller, connecting various parts of the entire controller using various interfaces and lines.

[0153] The memory can be used to store the computer program and / or module, and the processor implements various functions of the controller by running or executing the computer program and / or module stored in the memory, and calling the data stored in the memory. The memory can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage device.

[0154] Wherein, if the module / unit integrated in the controller is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the process in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, it can implement the steps of the above-mentioned various method embodiments. Wherein, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0155] It should be noted that the device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed across multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment. In addition, in the drawings of the device embodiments provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, which may be specifically implemented as one or more communication buses or signal lines. A person of ordinary skill in the art can understand and implement the present invention without inventive effort.

[0156] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A refrigerator, characterized in that: include: A compressor, whose driving mechanism is an electric motor; A controller for: When a start command is received, controlling the rotor of the motor to rotate; After determining that the rotor rotates to the positioning angle, controlling the motor to start the drag; During the driving process of the motor, detecting the back electromotive force parameter and the speed of the motor when its rotor rotates to N preset angles; wherein the back electromotive force parameter is the ratio of the d-axis back electromotive force to the q-axis back electromotive force of the motor; Selecting a target angle from the N preset angles based on a magnitude relationship between back electromotive force parameters corresponding to the N preset angles and a preset interval, and a magnitude relationship between rotational speeds corresponding to the N preset angles and a preset threshold; The positioning angle is corrected to the target angle.

2. The refrigerator according to claim 1, wherein The target angle is selected from the N preset angles according to the magnitude relationship between the back electromotive force parameters corresponding to the N preset angles and the preset interval, and the magnitude relationship between the rotation speeds corresponding to the N preset angles and the preset threshold, specifically: For the characteristic parameters at the N preset angles, if the back electromotive force parameter corresponding to a preset angle is within a preset range and the rotation speed corresponding to the preset angle is not lower than a preset threshold, the preset angle is determined to be the target angle.

3. The refrigerator according to claim 1 or 2, wherein: The preset interval is 20% to 60%.

4. The refrigerator according to claim 3, wherein The back electromotive force parameters corresponding to any preset angle are obtained in the following way: Obtaining the stator current and stator voltage of the α-axis and the β-axis of the motor when the rotor thereof rotates to the preset angle; Calculating the α-axis back electromotive force and the β-axis back electromotive force according to the stator current and stator voltage of the α-axis and the β-axis, and the stator resistance and stator inductance of the motor obtained in advance; Calculating the d-axis back electromotive force and the q-axis back electromotive force according to the preset angle, the α-axis back electromotive force, and the β-axis back electromotive force; The ratio of the d-axis back electromotive force to the q-axis back electromotive force is calculated to obtain a back electromotive force parameter corresponding to the preset angle.

5. The refrigerator according to claim 4, wherein: The calculation formula of the α-axis back electromotive force is: ； The calculation formula of the β-axis back electromotive force is: ； The calculation formula of the d-axis back electromotive force is: ； The calculation formula of the q-axis back electromotive force is: ； in, is the α-axis back electromotive force; are the β-axis back electromotive force respectively; is the α-axis stator voltage of the motor; is the β-axis stator voltage of the motor; is the α-axis stator current of the motor; is the β-axis stator current of the motor; is the stator resistance of the motor; is the stator inductance of the motor; is the d-axis back electromotive force; is the q-axis back electromotive force; is the preset angle.

6. A motor startup optimization method, characterized in that: include: When receiving a start command, the motor's rotor is controlled to rotate; After determining that the rotor rotates to the positioning angle, controlling the motor to start the drag; During the driving process of the motor, detecting the back electromotive force parameter and the speed of the motor when its rotor rotates to N preset angles; wherein the back electromotive force parameter is the ratio of the d-axis back electromotive force to the q-axis back electromotive force of the motor; Selecting a target angle from the N preset angles based on a magnitude relationship between back electromotive force parameters corresponding to the N preset angles and a preset interval, and a magnitude relationship between rotational speeds corresponding to the N preset angles and a preset threshold; The positioning angle is corrected to the target angle.

7. The motor startup optimization method according to claim 6, characterized in that: The target angle is selected from the N preset angles according to the magnitude relationship between the back electromotive force parameters corresponding to the N preset angles and the preset interval, and the magnitude relationship between the rotation speeds corresponding to the N preset angles and the preset threshold, specifically: For the characteristic parameters at the N preset angles, if the back electromotive force parameter corresponding to a preset angle is within a preset range and the rotation speed corresponding to the preset angle is not lower than a preset threshold, the preset angle is determined to be the target angle.

8. The motor startup optimization method according to claim 6, characterized in that: The preset interval is 20% to 60%.

9. The motor startup optimization method according to claim 8, characterized in that: The back electromotive force parameters corresponding to any preset angle are obtained in the following way: Obtaining the stator current and stator voltage of the α-axis and the β-axis of the motor when the rotor thereof rotates to the preset angle; Calculating the α-axis back electromotive force and the β-axis back electromotive force according to the stator current and stator voltage of the α-axis and the β-axis, and the stator resistance and stator inductance of the motor obtained in advance; Calculating the d-axis back electromotive force and the q-axis back electromotive force according to the preset angle, the α-axis back electromotive force, and the β-axis back electromotive force; The ratio of the d-axis back electromotive force to the q-axis back electromotive force is calculated to obtain a back electromotive force parameter corresponding to the preset angle.

10. The motor startup optimization method according to claim 9, characterized in that: The calculation formula of the α-axis back electromotive force is: ； The calculation formula of the β-axis back electromotive force is: ； The calculation formula of the d-axis back electromotive force is: ； The calculation formula of the q-axis back electromotive force is: ； in, is the α-axis back electromotive force; are the β-axis back electromotive force respectively; is the α-axis stator voltage of the motor; is the β-axis stator voltage of the motor; is the α-axis stator current of the motor; is the β-axis stator current of the motor; is the stator resistance of the motor; is the stator inductance of the motor; is the d-axis back electromotive force; is the q-axis back electromotive force; is the preset angle.

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