Method, medium and equipment for identifying initial position of permanent magnet synchronous motor

Abstract

The invention provides a permanent magnet synchronous motor initial position identification method, a medium and equipment in order to solve the problem that in the prior art, it is difficult to identify initial positions under the condition that direct-axis inductance and quadrature-axis inductance are equal or similar, and relates to the field of permanent magnet synchronous motor control. According to the voltage output under the alpha-beta two-phase static coordinate system, the three-phase current of the motor and the relevant parameters of the three-phase inverter, constructing a dead-zone compensation module to compensate the voltage output under the alpha-beta coordinate system; one electric period is equally divided into 24 parts to form 24 direction angles, and voltage is injected into the d axis of the rotor according to the 24 direction angles; and comparing the maximum amplitude of the current response of the d-axis injection voltage of each direction angle, wherein the direction corresponding to the maximum amplitude is the direction where the N pole of the magnetic pole is located. The method can effectively solve the problem of initial position identification under the condition that the direct-axis inductance and the quadrature-axis inductance are equal or similar.

Description

Technical Field

[0001] The present invention relates to the field of permanent magnet synchronous motor control, and particularly to a method, medium, and device for identifying the initial position of a permanent magnet synchronous motor. Background Art

[0002] An AC permanent magnet synchronous motor is a multi-variable and non-linear coupled system. Generally, its mathematical model is transformed into a two-phase rotating coordinate system through coordinate transformation, and the magnetic flux and torque are controlled on the direct axis and the quadrature axis respectively through field-oriented control technology. Whether in the starting stage or during actual operation, a relatively accurate rotor position needs to be obtained for a permanent magnet synchronous motor. When using an absolute encoder as the position acquisition means, the initial position can be obtained. However, for the application of a machine tool spindle, due to the high cost of the absolute encoder and its low adaptability to harsh operating conditions, an incremental encoder or sensorless sampling technology is generally used for control. Therefore, there is a strong demand for identifying the initial position of a permanent magnet synchronous motor.

[0003] For the identification method of the initial position of a permanent magnet synchronous motor, it is generally divided into a stationary identification method and a non-stationary identification method according to whether the rotor needs to rotate. The non-stationary identification method generally rotates the rotor to a specific position by applying a torque in a specific direction, mainly using a fixed-direction voltage or current injection method, or a low-frequency rotating signal injection method; the stationary identification method generally uses a high-frequency voltage excitation signal injection method, and the rotor position information is obtained by observing and calculating the generated current response, which can be further divided into a rotating high-frequency signal injection method, a pulsating high-frequency signal injection method, a pulse voltage injection method, etc.

[0004] The non-stationary identification method is relatively simpler. However, for many application scenarios, due to the presence of heavy loads or the relevant mechanisms not meeting the rotation conditions, this method cannot be used. For the stationary identification method, in the rotating high-frequency injection signal injection method, three-phase symmetrical sinusoidal voltage signals are injected into the stationary coordinate system, and the negative-sequence components of the current response are extracted. After filtering out the high-frequency components contained therein using a low-pass filter, the rotor magnetic pole position is obtained through the arctangent or phase-locked loop method. This method utilizes the salient-pole property of the permanent magnet synchronous motor to complete the identification of the rotor position. It cannot be applied to the surface-mounted permanent magnet synchronous motor with equal direct-axis inductance and quadrature-axis inductance. Moreover, for the interior permanent magnet synchronous motor with too small a difference between the direct-axis and quadrature-axis inductances, there will also be a phenomenon of poor identification result accuracy. At the same time, it is limited by the delay of the band-pass and low-pass filters, and there are also requirements for the amplitude of the injected signal to maintain stationarity, which will also reduce the accuracy; in the pulsating high-frequency signal injection method, a high-frequency sinusoidal voltage signal is injected into the direct axis in the two-phase rotating coordinate system. By extracting the current response of the quadrature axis and filtering out the high-frequency components using a low-pass filter, the rotor position signal is also obtained through the arctangent or phase-locked loop method. It is less affected by non-linearity, but it is also limited by the filter, which will introduce a reduction in accuracy. It also needs to rely on the salient-pole property of the permanent magnet synchronous motor to complete the identification. Therefore, it is also not applicable to the surface-mounted permanent magnet synchronous motor or the interior permanent magnet synchronous motor with a small difference between the direct-axis and quadrature-axis inductances; in the pulse voltage injection method, a series of voltage pulse signals with the same amplitude but different directions are injected into the motor stator in sequence. The direction of the rotor position is determined by the amplitude of the current response in the injection direction. Since the pulse voltage method generally only needs to inject voltage pulses for 1 PWM cycle, it will not cause the rotor to rotate. At the same time, because it is a fixed-direction voltage injection, a relatively high current response amplitude can be obtained. Since the magnetic flux of the permanent magnet synchronous motor is often designed at a position near the saturation region in consideration of the operation efficiency problem during design, when the magnetic flux continues to increase by a certain amount, it will cause the equivalent inductance of the armature winding to saturate, resulting in the direct-axis inductance being less than the quadrature-axis inductance. Therefore, when using the pulse voltage injection method for rotor position identification, it is not required that the motor itself has the characteristic of unequal direct-axis inductance and quadrature-axis inductance. It can be used in various scenarios such as surface-mounted permanent magnet synchronous motors and interior permanent magnet synchronous motors.

[0005] When the pulse voltage injection method is used to identify the initial position of a permanent magnet synchronous motor, generally due to the existence of the dead zone effect, it is difficult to ensure that the amplitudes of the injected voltages in different directions are equal. When the amplitudes of the injected voltages are the same, for the positive and negative directions of the rotor magnetic pole axis, the magnetic flux saturation degree in the same direction as the N pole is higher. Therefore, when the injected voltage is large enough, the maximum value of the current response amplitude in the N pole direction will be higher than that in the S pole direction. However, since it is difficult to ensure that the actual amplitudes of the injected voltages in different directions are equal, it is generally difficult to distinguish the positive and negative directions of the rotor magnetic pole position when identifying the rotor magnetic pole position, and it is necessary to separately distinguish the magnetic pole position.

[0006] In summary, the existing technologies have not been able to well solve the problem of initial position identification of permanent magnet synchronous motors, and there are certain defects in terms of identification accuracy and simplicity of identification. Summary of the Invention

[0007] The purpose of the present invention is to: in order to solve the problem that it is difficult to identify the initial position when the direct-axis and quadrature-axis inductances are equal or close in the existing technology, a method for identifying the initial position of a permanent magnet synchronous motor is proposed, including the following steps:

[0008] S1. On the basis of the vector control of the permanent magnet synchronous motor, construct a dead zone compensation module to compensate the voltages V α and V β according to the voltages V a and V b in the αβ coordinate system, the three-phase currents i c of the motor; α and V β ;

[0009] S2. Divide an electrical cycle into 24 equal parts to form 24 direction angles, and inject voltages into the d-axis of the rotor according to the 24 direction angles respectively;

[0010] S3. Compare the maximum values of the current response amplitudes of the voltages injected into the d-axis for each direction angle, and the direction corresponding to the maximum amplitude is the direction where the magnetic pole N is located.

[0011] Further, the equivalent dead zone voltage generated by the dead zone compensation module in one PWM cycle is:

[0012]

[0013] where s represents the stator vector direction, s ∈ {a, b, c}, V error represents the stator equivalent dead zone voltage, V s represents the IGBT conduction voltage drop, i s represents the stator current, t d represents the dead zone time, t onRepresents the equivalent conduction time of the switching transistor, t off Represents the equivalent turn-off time of the switching transistor, V e Represents the conduction voltage drop of the power diode, V dc Represents the DC bus voltage, k pwm Represents the high-level duty cycle of the pwm signal, T s Represents the pwm cycle time.

[0014] Further, the equivalent dead-time voltages of the three phases a, b, and c are transformed to the two-phase stationary coordinate system, obtaining:

[0015]

[0016] Among them, V comα Represents the equivalent dead-time voltage of phase α in the two-phase stationary coordinate system, V comβ Represents the equivalent dead-time voltage of phase β in the two-phase stationary coordinate system, V error_a Represents the equivalent dead-time voltage of phase a, V error_b Represents the equivalent dead-time voltage of phase b, V error_c Represents the equivalent dead-time voltage of phase c.

[0017] Further, the injected voltage is expressed in the stationary coordinate system as:

[0018]

[0019] Among them, V α Represents the equivalent voltage of phase α of the injected voltage in the two-phase stationary coordinate system, V β Represents the equivalent voltage of phase β of the injected voltage in the two-phase stationary coordinate system, V dref Represents the amplitude of the injected voltage during initial position identification, and θ represents the direction angle corresponding to the sequentially injected voltage.

[0020] Further, the sequence of the 24 direction angles is in turn: 0°, 180°, 15°, -165°, 30°, -150°, 45°, -135°, 60°, -120°, 75°, -105°, 90°, -90°, 105°, -75°, 120°, -60°, 135°, -45°, 150°, -30°, 165°, -15°.

[0021] Further, the specific method of injecting voltage into the d-axis of the rotor according to the 24 direction angles is as follows:

[0022] According to the sequence of the 24 direction angles, inject the voltage for 1 PWM cycle at each direction angle. After the injection is completed, output zero voltage for m PWM cycles, and then start injecting voltage from the next direction angle.

[0023] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-described method for identifying the initial position of a permanent magnet synchronous motor.

[0024] The present invention also provides an electronic device, including a processor and a memory, the processor being interconnected with the memory. Among them, the memory is used to store a computer program, the computer program includes computer-readable instructions, and the processor is configured to call the computer-readable instructions to execute the above-described method for identifying the initial position of a permanent magnet synchronous motor.

[0025] The beneficial effects brought by the technical solution provided by the present invention are as follows:

[0026] The present invention uses the pulse voltage injection method with a dead zone compensation link to identify the initial position of a permanent magnet synchronous motor. According to the positive and negative directions of the three-phase current, the dead zone voltage generated by the dead zone effect is equivalently compensated by changing the average voltage output within a PWM cycle. The initial position identification method of the present invention has no requirement for the difference between the direct-axis and quadrature-axis inductances, effectively solving the problem of identifying the initial position when the direct-axis and quadrature-axis inductances are equal or close. It has a wide adaptability and a high identification accuracy; with the help of the dead zone compensation link, it is ensured that the actual output voltage amplitudes in different injection directions are basically equal, and the positive and negative polarities of the magnetic poles can be determined simultaneously during the initial position identification process, with a high degree of simplicity and strong reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a flowchart of the method for identifying the initial position of a permanent magnet synchronous motor according to an embodiment of the present invention;

[0028] Figure 2 is a principle block diagram of the method for identifying the initial position of a permanent magnet synchronous motor based on motor vector control and dead zone compensation according to an embodiment of the present invention;

[0029] Figure 3 is a schematic diagram of the dead zone effect of a single-phase bridge arm of an inverter according to an embodiment of the present invention;

[0030] Figure 4 is a block diagram of an electronic device in an exemplary embodiment according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

[0032] The flowchart of the method for identifying the initial position of a permanent magnet synchronous motor according to an embodiment of the present invention is as Figure 1 , and specifically includes the following steps:

[0033] S1. Based on the vector control of the permanent magnet synchronous motor, a dead - zone compensation module is constructed according to the voltage V in the αβ two - phase stationary coordinate system, α and V β , the three - phase current i a , i b , i c , and the relevant parameters of the three - phase inverter to compensate the voltage V α and V β .

[0034] The principle block diagram of the initial position identification method of the permanent magnet synchronous motor based on motor vector control and dead - zone compensation in the embodiment of the present invention is referred to Figure 2 .

[0035] When using the pulse voltage injection method for the initial position identification of the permanent magnet synchronous motor, injecting voltage from the d - axis before the Park inverse transformation. Due to the existence of the hardware dead - zone of the inverter and the software dead - zone time that must be added to avoid the conduction of the positive and negative poles of the same phase, the given injected voltage value cannot act on the permanent magnet synchronous motor winding with the given amplitude as expected, but will be weakened due to the dead - zone effect. Moreover, since the actual winding has only three phases, when injecting voltage in different directions, the influence of the dead - zone effect on the injected voltage is different, which will also cause the current response results in each direction to be affected to different degrees, greatly affecting the comparison result of the maximum amplitude.

[0036] Taking the a - phase current as an example, the relevant calculation of the dead - zone voltage is carried out. When the a - phase current is positive, in a PWM cycle, the actual conduction time of the upper - arm switch tube is:

[0037] T u上 = k pwm T s - t d - t on + t off ,

[0038] where, T u上 represents the actual conduction time of the upper - arm switch tube, k pwm represents the a - phase duty cycle, t d represents the software - set dead - zone time, T s represents the pwm cycle time, t on represents the equivalent conduction time considering the transition process of the switch - tube conduction, and t off represents the equivalent turn - off time considering the transition process of the switch - tube turn - off.

[0039] When the a - phase is conducting, it is connected to the positive power supply through the upper - arm IGBT, and when the a - phase is turned off, it is connected to the negative power supply through the lower - arm power diode. Their input voltages are respectively:

[0040]

[0041] Among them, V + represents the input voltage when the upper bridge arm is conducting, V - represents the input voltage when the upper bridge arm is turned off, V dc represents the DC bus voltage, V s represents the conduction voltage drop of the IGBT, V d represents the conduction voltage drop of the power diode.

[0042] When the current of phase a is negative, in a PWM cycle, the actual conduction time of the lower bridge arm of the switch is:

[0043] T u下 =(1 - k pwm )T s -t d -t on +t off ,

[0044] Among them, T u下 represents the actual conduction time of the lower bridge arm of the switch.

[0045] When phase a is conducting, it is connected to the negative pole of the power supply through the IGBT of the lower bridge arm, and when phase a is turned off, it is connected to the positive pole of the power supply through the power diode of the upper bridge arm. Their input voltages are respectively:

[0046]

[0047] The schematic diagram of the dead-time effect of the single-phase bridge arm of the inverter in the embodiment of the present invention refers to Figure 3 , Figure 3 In it, t0 represents the moment when the turn-off signal of the lower bridge arm is given, t1 represents the actual moment when the lower bridge arm is turned off, t2 represents the moment when the turn-on signal of the upper bridge arm is given, t3 represents the actual moment when the upper bridge arm is turned on, t4 represents the moment when the next turn-off signal of the lower bridge arm is given, t5 represents the actual moment when the next lower bridge arm is turned off, t6 represents the moment when the next turn-on signal of the upper bridge arm is given, t7 represents the actual moment when the next upper bridge arm is turned on, t d represents the dead-time set by the software, t on represents the equivalent conduction time considering the transition process of the switch conduction, t off represents the equivalent turn-off time considering the transition process of the switch turn-off, V s represents the conduction voltage drop of the IGBT, V d represents the conduction voltage drop of the power diode, SGL_H * represents the ideal given signal of the upper bridge arm, SGL_L *represents the ideal given signal of the lower bridge arm, SGL_H represents the given signal of the upper bridge arm considering the software dead time, and SGL_L represents the given signal of the lower bridge arm considering the software dead time. represents the conduction voltage amplitude of the upper bridge arm of phase a considering the conduction voltage drops of IGBT and power diode. represents the conduction voltage amplitude of the lower bridge arm of phase a considering the conduction voltage drops of IGBT and power diode. represents the conduction voltage amplitude of the upper bridge arm of phase a considering the software dead time and the turn-on and turn-off times of the power module. represents the conduction voltage amplitude of the lower bridge arm of phase a considering the software dead time and the turn-on and turn-off times of the power module. S u represents the given signal of the upper bridge arm considering the software dead time and the turn-on and turn-off times of the power module. S d represents the given signal of the lower bridge arm considering the software dead time and the turn-on and turn-off times of the power module. i a represents the current of phase a. This figure illustrates the reason for the generation of the equivalent dead time voltage, that is, due to the deviation between the ideal conduction and turn-off moments and the actual conduction and turn-off moments in terms of time, and the difference between the ideal conduction voltage and the actual conduction voltage in terms of amplitude, ultimately resulting in the difference between the actual average voltage output and the ideal average voltage output within a PWM cycle time, that is, the equivalent dead time voltage.

[0048] Since the permanent magnet synchronous motor itself can be regarded as an element composed of a series connection of an inductor and a resistor, and its current cannot change suddenly, the dead time voltage generated by the dead time effect can be equivalently compensated by changing the average voltage output within a PWM cycle. It can be deduced from the above that the equivalent dead time voltage generated by the dead time effect within a PWM cycle is:

[0049]

[0050] Among them, s represents the stator vector direction, s ∈ {a, b, c}, V error represents the stator equivalent dead time voltage, V error ∈ {V error_a , V error_b , V error_c}, V error_a represents the equivalent dead time voltage of phase a, V error_b represents the equivalent dead time voltage of phase b, V error_c represents the equivalent dead time voltage of phase c, V s represents the IGBT conduction voltage drop, i s represents the stator current, t d represents the dead time, t on represents the equivalent conduction time of the switch tube, t off represents the equivalent turn-off time of the switch tube, Vd Denotes the conduction voltage drop of the power diode, V dc Denotes the DC bus voltage, k pwm Denotes the high-level duty cycle of the PWM signal, T s Denotes the PWM cycle time.

[0051] Convert the equivalent dead-time voltages of three phases a, b, and c to the two-phase stationary coordinate system, and obtain:

[0052]

[0053] Among them, V comα Denotes the equivalent dead-time voltage of phase α in the two-phase stationary coordinate system, V comβ Denotes the equivalent dead-time voltage of phase β in the two-phase stationary coordinate system, V error_a Denotes the equivalent dead-time voltage of phase a, V error_b Denotes the equivalent dead-time voltage of phase b, V error_c Denotes the equivalent dead-time voltage of phase c.

[0054] Since the injected voltage is injected along the given direction from the d-axis, the injected voltage is expressed in the stationary coordinate system as:

[0055]

[0056] Among them, V α Denotes the equivalent voltage of the injected voltage in phase α in the two-phase stationary coordinate system, V β Denotes the equivalent voltage of the injected voltage in phase β in the two-phase stationary coordinate system, V dref Denotes the amplitude of the injected voltage during initial position identification, and θ denotes the direction angle corresponding to the injected voltage in sequence.

[0057] Therefore, perform dead-time compensation on the injected voltage to obtain the output voltage actually output to the modulation link in the two-phase stationary coordinate system as:

[0058]

[0059] Among them, V dref Denotes the amplitude of the injected voltage during initial position identification, V outα Denotes the output voltage of the modulation link in phase α in the two-phase stationary coordinate system, that is, the voltage after dead-time compensation of the equivalent voltage of the injected voltage in phase α in the two-phase stationary coordinate system, V outβ Denotes the output voltage of the modulation link in phase β in the two-phase stationary coordinate system, that is, the voltage after dead-time compensation of the equivalent voltage of the injected voltage in phase β in the two-phase stationary coordinate system.

[0060] S2. Divide one electrical cycle into 24 equal parts to form 24 direction angles, and inject voltages into the d-axis of the rotor according to the 24 direction angles respectively.

[0061] The order of the 24 direction angles is as follows: 0°, 180°, 15°, -165°, 30°, -150°, 45°, -135°, 60°, -120°, 75°, -105°, 90°, -90°, 105°, -75°, 120°, -60°, 135°, -45°, 150°, -30°, 165°, -15°. According to the order of the 24 direction angles, inject the voltage for 1 PWM cycle at each direction angle. After the injection is completed, perform zero-voltage output for m PWM cycles, and then start injecting voltage from the next direction angle to ensure that the current in this direction has completed the discharge process after each injection.

[0062] S3. Compare the maximum values of the amplitudes of the current responses to the voltages injected into the d-axis at each direction angle. The direction corresponding to the maximum amplitude is the direction where the N pole of the magnetic pole is located.

[0063] Inject voltage for 1 PWM cycle in this direction after dead-time compensation each time according to the given injection voltage sequence, then perform zero-voltage output for 10 PWM cycles, and sample the maximum amplitude of the current response in this direction. Record the maximum value of the current amplitude after each voltage injection. After the overall injection is completed, compare the maximum values of the amplitudes of the current responses in each direction. The direction corresponding to the maximum amplitude is the direction where the N pole of the magnetic pole is located, that is, the initial position.

[0064] In an exemplary embodiment, it includes a computer-readable storage medium. The computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the above-mentioned method for identifying the initial position of a permanent magnet synchronous motor is implemented.

[0065] Please refer to Figure 4 , in an exemplary embodiment, it further includes an electronic device, which includes at least one processor, at least one memory, and at least one communication bus.

[0066] Among them, a computer program is stored on the memory. The computer program includes computer-readable instructions. The processor calls the computer-readable instructions stored in the memory through the communication bus and executes the above-mentioned method for identifying the initial position of a permanent magnet synchronous motor.

[0067] The foregoing description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for identifying the initial position of a permanent magnet synchronous motor, characterized in that, It includes the following steps: S1. Based on the vector control of the permanent magnet synchronous motor, construct a dead zone compensation module according to the voltages V α and V β in the αβ two-phase stationary coordinate system, the three-phase currents i a 、i b 、i c of the motor, and the relevant parameters of the three-phase inverter to compensate the voltages V α and V β ; S2. Divide an electrical cycle into 24 equal parts to form 24 direction angles, and inject voltages into the d-axis of the rotor according to the 24 direction angles respectively; S3. Compare the maximum values of the current responses of the voltages injected into the d-axis for each direction angle, and the direction corresponding to the maximum amplitude is the direction where the N pole of the magnetic pole is located.

2. A method for identifying the initial position of a permanent magnet synchronous motor according to claim 1, characterized in that The equivalent dead-time voltage generated by the dead-time compensation module within one PWM cycle is: Among them, s represents the stator vector direction, s ∈ {a, b, c}, V error represents the stator equivalent dead-time voltage, V s represents the IGBT conduction voltage drop, i s represents the stator current, t d represents the dead time, t on represents the equivalent conduction time of the switch tube, t off represents the equivalent turn-off time of the switch tube, V d represents the conduction voltage drop of the power diode, V dc represents the DC bus voltage, k pwm represents the high-level duty cycle of the pwm signal, T s represents the pwm cycle time.

3. The initial position identification method of a permanent magnet synchronous motor according to claim 2, wherein Convert the equivalent dead-time voltages of the three phases a, b, and c to the two-phase stationary coordinate system to obtain: Among them, V comα represents the equivalent dead-time voltage of the α-phase in the two-phase stationary coordinate system, V comβ represents the equivalent dead-time voltage of the β-phase in the two-phase stationary coordinate system, V error_a represents the equivalent dead-time voltage of the a-phase, V error_b represents the equivalent dead-time voltage of the b-phase, V error_c represents the equivalent dead-time voltage of the c-phase.

4. A method for identifying the initial position of a permanent magnet synchronous motor according to claim 1, characterized in that The injected voltage is expressed in the stationary coordinate system as: Among them, V α represents the equivalent voltage of the injected voltage in the α-phase of the two-phase stationary coordinate system, V β represents the equivalent voltage of the injected voltage in the β-phase of the two-phase stationary coordinate system, V dref represents the amplitude of the injected voltage during initial position identification, and θ represents the direction angle corresponding to the injected voltage in sequence.

5. A method for identifying the initial position of a permanent magnet synchronous motor according to claim 1, characterized in that The sequence of the 24 direction angles is in turn: 0°, 180°, 15°, -165°, 30°, -150°, 45°, -135°, 60°, -120°, 75°, -105°, 90°, -90°, 105°, -75°, 120°, -60°, 135°, -45°, 150°, -30°, 165°, -15°.

6. A method for identifying the initial position of a permanent magnet synchronous motor according to claim 4, characterized in that, The specific method of injecting voltages into the d-axis of the rotor according to the 24 direction angles is: According to the sequence of the 24 direction angles, inject the voltage for 1 PWM cycle at each direction angle. After the injection is completed, output zero voltage for m PWM cycles, and then start injecting voltage from the next direction angle.

7. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by the processor, it implements the method according to any one of claims 1-6.

8. An electronic device, characterized in that, It includes a processor and a memory. The processor is connected to the memory. Among them, the memory is used to store a computer program. The computer program includes computer-readable instructions. The processor is configured to call the computer-readable instructions to execute the method according to any one of claims 1-6.

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