Constant spinning tension dynamic monitoring and control method based on inverter, single spindle and single electric motor

Abstract

The present invention belongs to the field of dynamic monitoring and control of constant spinning tension. Specifically, disclosed is a constant spinning tension dynamic monitoring and control method based on an inverter, a single spindle and a single electric motor. The method comprises: acquiring the spinning tension of a spinning frame; calculating a control variable of an inverter; the inverter generating a gate signal; and adjusting the speed of an electric motor. In the present invention, a structural form of a two-component magneto-dependent sensor having automatic complementary functionality is used, and spinning tension is monitored in real time by means of a Hall sensor; the Hall sensor is fixed on a frame of a spinning frame, and a yarn guide of the spinning frame is connected to an input end, so as to measure the spinning tension; and a control variable outputted by a PID controller algorithm is used to adjust the speed of an electric motor, so as to reduce the intensity of manual labor and the impact of human factors, thereby achieving precise control over constant spinning tension.

Description

Dynamic monitoring and control method of constant tension of spinning yarn based on frequency converter single spindle single motor Technical Field

[0001] The present invention relates to the field of dynamic monitoring and control of constant tension of spun yarn, and in particular to a method for dynamic monitoring and control of constant tension of spun yarn based on a frequency converter, a single spindle and a single motor. Background Art

[0002] Spinning frames are important equipment in the textile industry, primarily used for spinning fibers such as cotton, wool, and linen. During the production process, yarn tension has a significant impact on product quality and production efficiency. Traditional spinning frames face technical challenges: The yarn tension measurement technology for all spindles is extremely difficult to acquire, preventing timely adjustment and processing. The yarn tension detection device is difficult to secure, making it inconvenient for employees to operate and preventing online monitoring and control. Furthermore, the yarn tension control accuracy is low, resulting in difficulty maintaining consistent product quality, high energy consumption, and low production efficiency. Summary of the Invention

[0003] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a method for dynamic monitoring and control of constant tension of spinning based on a single-spindle and single-motor frequency converter. In view of the technical problems that the traditional spinning frame has great difficulty in collecting the yarn tension of all spindles of the spinning frame and cannot be adjusted and processed in time, the present invention adopts a two-component magnetic sensor with automatic complementary structure to monitor the yarn tension in real time through a Hall sensor; in view of the technical problems that the yarn tension detection device is difficult to fix, the employees are inconvenient to operate, and online monitoring and control cannot be achieved, the present invention fixes the Hall sensor on the spinning frame frame and connects the yarn guide hook of the spinning frame to the input end to detect the tension of the spinning; in view of the technical problems that the yarn tension control precision is not high, the product quality is difficult to maintain consistency, the energy consumption is large, and the production efficiency is low, the present invention adopts the control quantity output by the PID controller algorithm to adjust the speed of the motor, which reduces the labor intensity and the influence of human factors, and realizes precise control of the constant tension of the spinning.

[0004] The technical solution adopted by the present invention is as follows: The present invention provides a method for dynamic monitoring and control of constant tension of spinning based on a frequency converter single spindle single motor, the method comprising the following steps:

[0005] Step S1: obtaining the spinning tension of a spinning frame, wherein the spinning frame includes a frame, a fixed base, a yarn guide hook, a frequency converter and a motor, wherein the fixed base is arranged on the frame, the yarn guide hook is fixed on the fixed base, and the frequency converter, the motor and the frame are fixedly connected;

[0006] Step S2: Calculate the control quantity of the frequency converter;

[0007] Step S3: The frequency converter generates a gate signal;

[0008] Step S4: Motor speed regulation.

[0009] Furthermore, in step S1, obtaining the spinning tension of the spinning frame specifically includes the following steps:

[0010] Step S11: Installing a Hall sensor, which is set on a frame and includes a uniform cross-section elastic sheet, a torsion shaft, a magnetic sheet, and a two-component magnetic sensor. The uniform cross-section elastic sheet is fixed to a fixed base. The torsion shaft includes an input end and an output end. The torsion shaft passes through the fixed base and the center of the uniform cross-section elastic sheet. The input end is connected to a yarn guide hook, and the output end is connected to a frequency converter. The magnetic sheet is fixed to the output end, and the two-component magnetic sensor is fixed to the magnetic sheet.

[0011] Step S12: collecting a yarn tension data set, wherein the yarn tension data set includes an electrical signal and yarn tension;

[0012] Step S13: creating and initializing an artificial neural network, training the artificial neural network using the yarn tension data set, the artificial neural network outputting the yarn tension, and integrating the trained artificial neural network into the two-component magnetic sensor;

[0013] Step S14: When the spinning frame is running, the yarn is connected to the yarn guide hook. When the yarn tension fluctuates, the input end of the torsion shaft senses the change in yarn tension through the yarn guide hook, causing the uniform cross-section elastic sheet to twist. The position of the output end changes, generating a Hall effect, and the two-component magnetic sensor generates an electrical signal. The artificial neural network outputs the yarn tension according to the electrical signal.

[0014] Step S15: The Hall sensor sends the yarn tension to the frequency converter.

[0015] Furthermore, in step S2, the control variable of the frequency converter is calculated, which specifically includes the following steps:

[0016] Step S21: Modeling the motor. The motor is a three-phase brushless DC motor. The three phases are A, B, and C. Phase A of the motor is simulated using a mathematical method. The formula used is as follows:

[0017]

[0018] Where V is the phase voltage of phase A, R is the phase resistance of phase A, i is b and i c are the phase currents of phase A, phase B and phase C respectively, and are the rates of change of phase A, phase B, and phase C respectively, L is the phase inductance of phase A, M ab and M acare the mutual inductances of phase A with phases B and C, respectively, and e is the back electromotive force of phase A;

[0019] Step S22: Calculate the back electromotive force of each phase using the following formula:

[0020]

[0021]

[0022]

[0023] Where, e a 、e b and e c They are the back electromotive force of the three phases, K e is the back EMF constant, w m is the mechanical angular velocity of the motor, θ e is the rotor angle, F(θ e ) is the position function of the rotor;

[0024] Step S23: Calculate the electromagnetic torque of the motor using the following formula:

[0025]

[0026] Where, T e is the electromagnetic torque of the motor, K t is the torque constant;

[0027] Step S24: Preset the desired tension and calculate the error between the yarn tension and the desired tension;

[0028] Step S25: Calculate the gain parameter of the frequency converter, and define the constraint condition of the gain parameter as follows:

[0029]

[0030] Where r is the error, j is the control variable, X is the sensitivity function of the inverter's response to changes in the input signal, Y is the sensitivity function of the inverter's response to changes in the input power, Z is the sensitivity function of the inverter's complementary response to the input signal, W1, W2, and W2 are the weights of X, Y, and Z, respectively, γ is the preset maximum value of the output signal, and ||Z rj ||∞ is Z rj Chebyshev distance;

[0031] Step S26: Calculate the error and weight using the hinfsyn function in the MATLAB script to obtain a transfer function, and calculate the transfer function using the particle swarm optimization algorithm to obtain the optimal weight;

[0032] Step S27: Calculate the error according to the optimal weight and PID control algorithm to obtain the control value of the inverter.

[0033] Furthermore, in step S3, the frequency converter generates a gate signal, which specifically includes the following steps:

[0034] Step S31: The frequency converter generates a pulse width modulation signal according to the control variable;

[0035] Step S32: A decoder is provided inside the inverter. The phase of the motor includes a door switch, a rotor and a built-in Hall sensor. The door switch includes an upper switch and a lower switch. The built-in Hall sensor measures the position of the rotor to obtain a position signal, and sends the position signal to the decoder. The decoder generates a door signal based on the pulse width modulation signal and the control quantity.

[0036] Furthermore, in step S4, the motor speed regulation specifically includes the following steps:

[0037] Step S41: The rotor includes two magnetic poles. When the magnetic poles of the rotor are close together, the built-in Hall sensor sends a strong signal. When the magnetic poles of the rotor are far apart, the built-in Hall sensor sends a weak signal.

[0038] Step S42: The built-in Hall sensor outputs an accurate equivalent commutation sequence;

[0039] Step S43: Using the gate signal to control the gate switch, the gate switch controls the phase terminal voltage of the motor to adjust the speed of the motor;

[0040] Step S44: Energize the three phases, and assume that phase A, phase B and phase C are connected to the corresponding door switches with yellow wire, blue wire and green wire respectively. Assume that phase C remains non-polarized initially, phase A obtains positive voltage, and phase B obtains negative voltage. Open the upper switch of phase A, connect the positive pole of phase A to the yellow wire, open the lower switch of phase B, connect the negative pole of phase B to the blue wire, and keep the other switches open. Use one upper switch and one lower switch to engage at the same time to adjust the phase terminal voltage and control the motor speed.

[0041] The beneficial effects achieved by the present invention using the above scheme are as follows:

[0042] (1) In view of the technical problem that the traditional spinning frame has great difficulty in collecting the yarn tension of all spindles and cannot be adjusted and processed in time, the present invention adopts a dual-component magnetic sensor automatic complementary structure to monitor the yarn tension in real time through a Hall sensor;

[0043] (2) In order to solve the technical problems that the yarn tension detection device is difficult to fix, inconvenient for employees to operate, and cannot realize online monitoring and control, the present invention fixes the Hall sensor on the frame of the spinning frame and connects the yarn guide hook of the spinning frame to the input end to detect the yarn tension;

[0044] (3) The technical problems of low control precision of yarn tension, difficulty in maintaining consistent product quality, high energy consumption and low production efficiency are solved by the present invention. The control quantity output by the PID controller algorithm is used to adjust the speed of the motor, which reduces the labor intensity and the influence of human factors and realizes precise control of the constant tension of the yarn. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG1 is a flow chart of a method for dynamic monitoring and control of constant tension of spinning yarn based on a frequency converter, a single spindle and a single motor, proposed by the present invention;

[0046] FIG2 is a schematic structural diagram of a spinning frame with a fixed Hall sensor according to the present invention;

[0047] FIG3 is a schematic structural diagram of a yarn guide hook proposed in the present invention for collecting tension signals;

[0048] FIG4 is a schematic structural diagram of the input end and the output end proposed by the present invention.

[0049] Among them, 1. yarn, 4. yarn guide hook, 5. input end, 8. fixed base, 13. torsion shaft, 14. magnetic sheet, 15. uniform cross-section elastic sheet, 16. two-component magnetic sensor, 19. frame, 24. output end, 25. motor, 26. inverter.

[0050] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0052] In the description of the present invention, it should be understood that terms such as "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0053] Example 1: Referring to Figures 1 to 4, this embodiment provides a method for dynamic monitoring and control of constant tension of spinning based on a frequency converter, a single spindle, and a single motor. The method includes the following steps:

[0054] Step S1: obtaining the yarn tension of the spinning frame, wherein the spinning frame includes a frame 19, a fixed base 8, a yarn guide hook 4, a frequency converter 26 and a motor 25, wherein the fixed base 8 is arranged on the frame 19, the yarn guide hook 4 is fixed on the fixed base 8, and the frequency converter 26, the motor 25 and the frame 19 are fixedly connected;

[0055] Step S2: Calculate the control amount of the frequency converter 26;

[0056] Step S3: The frequency converter 26 generates a gate signal;

[0057] Step S4: the motor 25 adjusts its speed.

[0058] Embodiment 2, referring to FIG1 to FIG4, this embodiment is based on the above embodiment. In step S1, the yarn tension of the spinning frame is obtained, which specifically includes the following steps:

[0059] Step S11: Installing a Hall sensor, which is set on the frame 19. The Hall sensor includes a uniform cross-section elastic sheet 15, a torsion shaft 13, a magnetic sheet 14, and a two-component magnetic sensor 16. The uniform cross-section elastic sheet 15 is fixed to the fixed base 8. The torsion shaft 13 includes an input end 5 and an output end 24. The torsion shaft 13 passes through the fixed base 8 and the center of the uniform cross-section elastic sheet 15. The input end 5 is connected to the yarn guide hook 4, and the output end 24 is connected to the frequency converter 26. The magnetic sheet 14 is fixed to the output end 24, and the two-component magnetic sensor 16 is fixed to the magnetic sheet 14.

[0060] Step S12: collecting a yarn tension data set, wherein the yarn tension data set includes an electrical signal and yarn tension;

[0061] Step S13: creating and initializing an artificial neural network, training the artificial neural network using the yarn tension data set, the artificial neural network outputting the yarn tension, and integrating the trained artificial neural network into the two-component magnetic sensor 16;

[0062] Step S14: When the spinning frame is running, the yarn 1 is connected to the yarn guide hook 4. When the yarn tension fluctuates, the input end 5 of the torsion shaft 13 senses the change in yarn tension through the yarn guide hook 4, causing the uniform cross-section elastic sheet 15 to twist. The position of the output end 24 changes, generating a Hall effect, and the two-component magnetic sensor 16 generates an electrical signal. The artificial neural network outputs the yarn tension according to the electrical signal.

[0063] Step S15 : the Hall sensor sends the yarn tension to the frequency converter 26 .

[0064] Through the above operations, in order to solve the technical problems that the yarn tension detection device is difficult to fix, inconvenient for employees to operate, and online monitoring and control cannot be achieved, the present invention fixes the Hall sensor on the frame 19 of the spinning frame, and connects the yarn guide hook 4 of the spinning frame with the input end 5 to detect the yarn tension; in order to solve the technical problems that the yarn tension collection technology of all spindles of the traditional spinning frame is extremely difficult and cannot be adjusted and processed in time, the present invention adopts a two-component magnetic sensor 16 automatic complementary structure to monitor the yarn tension in real time through the Hall sensor.

[0065] Embodiment 3, referring to FIG. 1 to FIG. 3 , this embodiment is based on the above embodiment. In step S2 , the control amount of the frequency converter 26 is calculated, specifically including the following steps:

[0066] Step S21: Modeling the motor 25. The motor 25 is a three-phase brushless DC motor. The three phases are A, B, and C. Phase A of the motor 25 is simulated using a mathematical method. The formula used is as follows:

[0067]

[0068] Where V is the phase voltage of phase A, R is the phase resistance of phase A, i is b and i c are the phase currents of phase A, phase B and phase C respectively, and are the rates of change of phase A, phase B, and phase C respectively, L is the phase inductance of phase A, M ab and M ac are the mutual inductance coefficients of phase A, B, and C respectively, and e is the back electromotive force of phase A.

[0069] Step S22: Calculate the back electromotive force of each phase using the following formula:

[0070]

[0071]

[0072]

[0073] Where, e a 、e b and e c They are the back electromotive force of the three phases, K e is the back EMF constant, w m is the mechanical angular velocity of the motor 25, θ e is the rotor angle, F(θ e ) is the position function of the rotor;

[0074] Step S23: Calculate the electromagnetic torque of the motor 25 using the following formula:

[0075]

[0076] Where, T e is the electromagnetic torque of the motor 25, K t is the torque constant;

[0077] Step S24: Preset the desired tension and calculate the error between the yarn tension and the desired tension;

[0078] Step S25: Calculate the gain parameter of the frequency converter 26, and define the constraint condition of the gain parameter as follows:

[0079]

[0080] Where r is the error, j is the control variable, X is the sensitivity function of the response of the frequency converter 26 to the input signal change, Y is the sensitivity function of the response of the frequency converter 26 to the input power change, Z is the sensitivity function of the complementary response of the output of the frequency converter 26 to the input signal, W1, W2 and W2 are the weights of X, Y and Z respectively, γ is the preset maximum value of the output signal, and ||Z rj ||∞ is Z rj Chebyshev distance;

[0081] Step S26: Calculate the error and weight using the hinfsyn function in the MATLAB script to obtain a transfer function, and calculate the transfer function using the particle swarm optimization algorithm to obtain the optimal weight;

[0082] Step S27: Calculate the error according to the optimal weight and the PID control algorithm to obtain the control amount of the frequency converter 26.

[0083] Embodiment 4, referring to FIG. 1 to FIG. 3 , this embodiment is based on the above embodiment. In step S3 , the frequency converter 26 generates a gate signal, specifically including the following steps:

[0084] Step S31: The frequency converter 26 generates a pulse width modulation signal according to the control variable;

[0085] Step S32: A decoder is provided inside the inverter 26. The phase of the motor 25 includes a door switch, a rotor and a built-in Hall sensor. The door switch includes an upper switch and a lower switch. The built-in Hall sensor measures the position of the rotor to obtain a position signal, and sends the position signal to the decoder. The decoder generates a door signal based on the pulse width modulation signal and the control amount.

[0086] Embodiment 5, referring to FIG. 1 to FIG. 3 , this embodiment is based on the above embodiment. In step S4 , the motor 25 is speed-regulated, specifically comprising the following steps:

[0087] Step S41: The rotor includes two magnetic poles. When the magnetic poles of the rotor are close together, the built-in Hall sensor sends a strong signal. When the magnetic poles of the rotor are far apart, the built-in Hall sensor sends a weak signal.

[0088] Step S42: The built-in Hall sensor outputs an accurate equivalent commutation sequence;

[0089] Step S43: Use the gate signal to control the gate switch, and the gate switch controls the phase terminal voltage of the motor to adjust the speed of the motor 25;

[0090] Step S44: Energize the three phases, and assume that phase A, phase B and phase C are connected to the corresponding door switches with yellow wires, blue wires and green wires respectively. Assume that phase C remains non-polarized initially, phase A obtains positive voltage, and phase B obtains negative voltage. Turn on the upper switch of phase A, connect the positive pole of phase A to the yellow wire, turn on the lower switch of phase B, connect the negative pole of phase B to the blue wire, and keep the other switches open. Use one upper switch and one lower switch to engage at the same time to adjust the phase terminal voltage and control the speed of motor 25.

[0091] Through the above operations, the technical problems of low yarn tension control accuracy, difficulty in maintaining consistent product quality, high energy consumption and low production efficiency are solved. The present invention adopts the control quantity output by the PID controller algorithm to adjust the speed of the motor 25, which reduces the labor intensity and the influence of human factors, and realizes precise control of the constant tension of the yarn.

[0092] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0093] While 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 these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

[0094] The present invention and its embodiments are described above. This description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if a person skilled in the art is inspired by this and, without departing from the purpose of the present invention, designs structures and embodiments similar to this technical solution without inventiveness, they shall fall within the scope of protection of the present invention.

Claims

1. A method for dynamic monitoring and control of constant tension of spinning yarn based on a frequency converter single spindle single motor, characterized in that: The method comprises the following steps: Step S1: obtaining the spinning tension of the spinning frame, wherein the spinning frame includes a frame, a fixed base, a yarn guide hook, a frequency converter and a motor, wherein the fixed base is arranged on the frame, the yarn guide hook is fixed on the fixed base, and the frequency converter, the motor and the frame are fixedly connected; Step S2: Calculate the control quantity of the frequency converter; Step S3: The frequency converter generates a gate signal; Step S4: Motor speed regulation.

2. The method for dynamic monitoring and control of constant tension of spinning yarn based on a frequency converter single spindle single motor according to claim 1, characterized in that: In step S1, the yarn tension of the spinning frame is obtained, which specifically includes the following steps: Step S11: Installing a Hall sensor, which is set on a frame and includes a uniform cross-section elastic sheet, a torsion shaft, a magnetic sheet, and a two-component magnetic sensor. The uniform cross-section elastic sheet is fixed to a fixed base. The torsion shaft includes an input end and an output end. The torsion shaft passes through the fixed base and the center of the uniform cross-section elastic sheet. The input end is connected to a yarn guide hook, and the output end is connected to a frequency converter. The magnetic sheet is fixed to the output end, and the two-component magnetic sensor is fixed to the magnetic sheet. Step S12: collecting a yarn tension data set, wherein the yarn tension data set includes an electrical signal and yarn tension; Step S13: creating and initializing an artificial neural network, training the artificial neural network using the yarn tension data set, the artificial neural network outputting the yarn tension, and integrating the trained artificial neural network into the two-component magnetic sensor; Step S14: When the spinning frame is running, the yarn is connected to the yarn guide hook. When the yarn tension fluctuates, the input end of the torsion shaft senses the change in yarn tension through the yarn guide hook, causing the uniform cross-section elastic sheet to twist. The position of the output end changes, generating a Hall effect, and the two-component magnetic sensor generates an electrical signal. The artificial neural network outputs the yarn tension according to the electrical signal. Step S15: The Hall sensor sends the yarn tension to the frequency converter.

3. The method for dynamic monitoring and control of constant tension of spinning yarn based on a frequency converter single spindle single motor according to claim 1, characterized in that: In step S2, the control quantity of the frequency converter is calculated, which specifically includes the following steps: Step S21: Modeling the motor. The motor is a three-phase brushless DC motor. The three phases are A, B, and C. Phase A of the motor is simulated using a mathematical method. The formula used is as follows: Where V is the phase voltage of phase A, R is the phase resistance of phase A, i is b and i c are the phase currents of phase A, phase B and phase C respectively, and are the rates of change of phase A, phase B, and phase C respectively, L is the phase inductance of phase A, M ab and M ac are the mutual inductances of phase A with phases B and C, respectively, and e is the back electromotive force of phase A; Step S22: Calculate the back electromotive force of each phase using the following formula: Where, e a 、e b and e c They are the back electromotive force of the three phases, K e is the back EMF constant, w m is the mechanical angular velocity of the motor, θ e is the rotor angle, F(θ e ) is the position function of the rotor; Step S23: Calculate the electromagnetic torque of the motor using the following formula: Where, T e is the electromagnetic torque of the motor, K t is the torque constant; Step S24: Preset the desired tension and calculate the error between the yarn tension and the desired tension; Step S25: Calculate the gain parameter of the frequency converter, and define the constraint condition of the gain parameter as follows: Where r is the error, j is the control variable, X is the sensitivity function of the inverter's response to changes in the input signal, Y is the sensitivity function of the inverter's response to changes in the input power, Z is the sensitivity function of the inverter's complementary response to the input signal, W1, W2, and W2 are the weights of X, Y, and Z, respectively, γ is the preset maximum value of the output signal, and ||Z rj ||∞ is Z rj Chebyshev distance; Step S26: Calculate the error and weight using the hinfsyn function in the MATLAB script to obtain a transfer function, and calculate the transfer function using the particle swarm optimization algorithm to obtain the optimal weight; Step S27: Calculate the error according to the optimal weight and PID control algorithm to obtain the control value of the inverter.

4. The method for dynamic monitoring and control of constant tension of spinning yarn based on a frequency converter single spindle single motor according to claim 1, characterized in that: In step S3, the frequency converter generates a gate signal, which specifically includes the following steps: Step S31: The frequency converter generates a pulse width modulation signal according to the control variable; Step S32: A decoder is provided inside the inverter. The phase of the motor includes a door switch, a rotor and a built-in Hall sensor. The door switch includes an upper switch and a lower switch. The built-in Hall sensor measures the position of the rotor to obtain a position signal, and sends the position signal to the decoder. The decoder generates a door signal based on the pulse width modulation signal and the control quantity.

5. The method for dynamic monitoring and control of constant tension of spinning yarn based on a frequency converter single spindle single motor according to claim 1, characterized in that: In step S4, the motor speed is adjusted, which specifically includes the following steps: Step S41: The rotor includes two magnetic poles. When the magnetic poles of the rotor are close together, the built-in Hall sensor sends a strong signal. When the magnetic poles of the rotor are far apart, the built-in Hall sensor sends a weak signal. Step S42: The built-in Hall sensor outputs an accurate equivalent commutation sequence; Step S43: Using the gate signal to control the gate switch, the gate switch controls the phase terminal voltage of the motor to adjust the speed of the motor; Step S44: Energize the three phases, and assume that phase A, phase B and phase C are connected to the corresponding door switches with yellow wire, blue wire and green wire respectively. Assume that phase C remains non-polarized initially, phase A obtains positive voltage, and phase B obtains negative voltage. Open the upper switch of phase A, connect the positive pole of phase A to the yellow wire, open the lower switch of phase B, connect the negative pole of phase B to the blue wire, and keep the other switches open. Use one upper switch and one lower switch to engage at the same time to adjust the phase terminal voltage and control the motor speed.

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