Sensorless Control Method and Related Device for Permanent Magnet Synchronous Linear Motor

Abstract

Sensorless control method and related device for permanent magnet synchronous linear motor, including: establishing a mathematical model of the permanent magnet synchronous linear motor; estimating back electromotive force information using a sliding mode observer according to the mathematical model of the permanent magnet synchronous linear motor; adaptively adjusting the proportional-integral gain of the phase-locked loop by using the stochastic gradient descent method, enabling the phase-locked loop to operate at a low bandwidth, and adjusting the bandwidth in real time when the speed changes, and extracting speed and position information from the estimated back electromotive force information. An adaptive phase-locked loop is introduced into the sensorless control system of the permanent magnet synchronous linear motor based on the sliding mode observer, and the proportional-integral gain of the phase-locked loop is adaptively adjusted by using the stochastic gradient descent method, enabling the phase-locked loop to operate at a low bandwidth, and adjusting the bandwidth in real time when the speed changes rapidly, and extracting speed and position information from the estimated back electromotive force information. It solves the contradiction problem between anti-interference performance and fast response in the sensorless control of the permanent magnet synchronous linear motor.

Description

Technical Field

[0001] The present invention belongs to the technical field of sensorless control of permanent magnet synchronous linear motors, and particularly relates to a sensorless control method and related devices for permanent magnet synchronous linear motors. Background Art

[0002] Linear motors have the advantages of simple structure, large acceleration, high positioning accuracy, low friction, and convenient maintenance. Compared with other linear motors, permanent magnet synchronous linear motors have the advantages of strong controllability, high power density, and high efficiency, and thus have been widely used in modern industry. The traditional driving method of linear motors uses mechanical sensors, which are expensive, have high requirements for the working environment, and require additional installation space, restricting the wide application of linear motors. Therefore, the research on sensorless control methods for linear motors has become a hot topic in recent years.

[0003] The essence of sensorless control of permanent magnet synchronous linear motors is to use electrical quantities such as voltage and current to estimate the speed and position of the motor mover. According to different principles, sensorless control methods can be divided into two categories: signal injection-based methods and model-based methods. Signal injection-based methods include low-frequency signal injection method, high-frequency signal injection method, etc. Model-based methods first perform back electromotive force or magnetic flux observation, and then estimate the speed and position of the mover based on the observed back electromotive force or magnetic flux. Methods for observing back electromotive force or magnetic flux include direct calculation method, model reference adaptive method, observer method, etc. The estimation of mover speed and position is usually completed by a phase-locked loop.

[0004] The sliding mode observer belongs to the observer method, which uses the difference between the state variable and the actual value as feedback, and controls the state variable to move on the set sliding mode surface through a switching function to achieve the estimation of the state variable. Compared with other observers, the sliding mode observer has a simple structure and high robustness, and is widely used in sensorless control of motors. The phase-locked loop is a closed-loop feedback system that can make the output signal synchronize with the input signal in terms of frequency and phase, and has been widely used in the field of sensorless control of motors. However, the traditional fixed-bandwidth phase-locked loop has poor dynamic performance. When the bandwidth is too large, the anti-interference ability is poor, and when the bandwidth is too small, it cannot respond to the rapid change of speed, thus affecting the estimation performance of sensorless control of permanent magnet synchronous linear motors. Summary of the Invention

[0005] The purpose of the present invention is to provide a sensorless control method and related devices for permanent magnet synchronous linear motors to solve the contradiction problem between anti-interference performance and fast response in the existing technology.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a sensorless control method for a permanent magnet synchronous linear motor, comprising:

[0008] Establish a mathematical model of permanent magnet synchronous linear motor;

[0009] According to the mathematical model of permanent magnet synchronous linear motor, the back electromotive force information is estimated by using sliding mode observer;

[0010] The stochastic gradient descent method is used to adaptively adjust the proportional integral gain of the phase-locked loop, so that the phase-locked loop can operate at low bandwidth, adjust the bandwidth in real time when the speed changes, and extract speed and position information from the estimated back electromotive force information.

[0011] Optionally, the establishment of a mathematical model of the permanent magnet synchronous linear motor includes:

[0012] The voltage equation of the permanent magnet synchronous linear motor is:

[0013]

[0014] In formula (1), u α 、u β are the components of the excitation voltage on the α and β axes respectively; R is the excitation resistance; i α 、i β are the components of the excitation current on the α and β axes respectively; L is the excitation inductance of the permanent magnet synchronous linear motor; τ is the permanent magnet pole pitch, v is the linear velocity of the rotor, ψ f is the permanent magnet flux; θ is the position of the mover.

[0015] Optionally, a sliding mode observer is used to estimate the back electromotive force information as follows:

[0016] Rewrite the permanent magnet synchronous linear motor voltage equation into a current state equation:

[0017]

[0018] In formula (2), e α 、e β is the back electromotive force:

[0019]

[0020] The sliding mode observer is designed according to formula (2). The observer and control generator are as follows:

[0021]

[0022] In formula (3), is the estimated value of the excitation current, z α 、z β The back EMF value estimated by the traditional sliding mode observer SMO is:

[0023]

[0024] In formula (4), sgn() is the sign function;

[0025] Subtracting Equation (3) from Equation (2) yields the current estimation error state equation:

[0026]

[0027] Construct the sliding surface s(x):

[0028]

[0029] According to the reachability condition of the sliding mode observer, the switching gain k in the sliding mode observer satisfies:

[0030] k>max(|e α |,|e β |) (8)

[0031] The switching function in the sliding mode observer will bring high-frequency interference to the estimated back EMF during high-frequency switching, affecting the estimation accuracy. Therefore, a low-pass filter is selected to filter out the high-frequency harmonics in the estimated back EMF:

[0032]

[0033] In formula (9), is the estimated value of back electromotive force after low-pass filter, ω c =2πf c , f c is the cutoff frequency of the low-pass filter, and s is the Laplace operator.

[0034] Optionally, the transfer function of the orthogonal phase-locked loop is as follows:

[0035]

[0036] In formula (10), kp and ki are the proportional and integral gains of the traditional orthogonal phase-locked loop PI controller;

[0037] Normalize the back EMF to:

[0038]

[0039] The transfer function then becomes:

[0040]

[0041] Optionally, the stochastic gradient descent method is used to adaptively adjust the proportional integral gain of the phase-locked loop to enable the phase-locked loop to operate at a low bandwidth:

[0042] The estimated back electromotive force information is input into a phase-locked loop, and the random gradient descent method is used to adaptively adjust the bandwidth of the quadrature phase-locked loop to minimize the estimation error. The PI gain coefficient is expressed as:

[0043]

[0044] In Equation (13), ξ is the damping coefficient, η is the center frequency, and l is the discrete time step;

[0045] The adaptive process should keep the damping coefficient at a constant value, so:

[0046]

[0047] In Equation (14), μ is the step size parameter that determines the adaptive speed, and δ[l] is the input error of the phase-locked loop PI controller;

[0048] The partial derivative solution in Equation (14) consists of two parts. The first part is:

[0049]

[0050]

[0051] At time [l - 1], the speed and position are estimated by the phase-locked loop PI controller, and the PI controller is rewritten in the speed form:

[0052]

[0053] In Equation (17), T s is the sampling time, m i is the PI integral register, and the integral is expressed as:

[0054]

[0055] Substituting Equation (17) into Equation (18), the second part is obtained:

[0056]

[0057] Combining Equation (16) and Equation (19), the parameter adjustment formula for the adaptive quadrature phase-locked loop is obtained:

[0058] η[l] = η[l - 1] - μz1[l]z2[l] = η[l - 1] - Δη[l] (20)

[0059] In Equation

[20] , z2[l] has been simplified, and a T s has become part of μ

[0060] z2[l] = 2ξδ[l - 1] + T sη[l-1](δ[l-1]+δ[l-2]) (21)

[0061] After the above process, the PI gain of the phase-locked loop is iteratively updated, and the bandwidth is adaptively adjusted according to the following speed.

[0062] In a second aspect, the present invention provides a sensorless control system for a permanent magnet synchronous linear motor, comprising:

[0063] A model establishment module for establishing a mathematical model of the permanent magnet synchronous linear motor;

[0064] An estimation module for estimating back electromotive force information by using a sliding mode observer according to the mathematical model of the permanent magnet synchronous linear motor;

[0065] A data extraction module for adaptively adjusting the proportional-integral gain of the phase-locked loop by using the stochastic gradient descent method, enabling the phase-locked loop to operate at a low bandwidth, and adjusting the bandwidth in real time when the speed changes, and extracting speed and position information from the estimated back electromotive force information.

[0066] In a third aspect, the present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the processor executes the computer program, the steps of the sensorless control method for the permanent magnet synchronous linear motor are implemented.

[0067] In a fourth aspect, the present invention provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the steps of the sensorless control method for the permanent magnet synchronous linear motor are implemented.

[0068] Compared with the prior art, the present invention has the following technical effects:

[0069] The present invention proposes a sensorless control method for a permanent magnet synchronous linear motor based on a bandwidth-adaptive sliding mode observer. An adaptive phase-locked loop is introduced into the sensorless control system of the permanent magnet synchronous linear motor based on the sliding mode observer, and the proportional-integral gain of the phase-locked loop is adaptively adjusted by using the stochastic gradient descent method, enabling the phase-locked loop to operate at a low bandwidth and adjusting the bandwidth in real time when the speed changes rapidly, and extracting speed and position information from the estimated back electromotive force information. The contradiction problem between the anti-interference performance and the fast response in the sensorless control of the permanent magnet synchronous linear motor is solved. Description of the Drawings

[0070] Figure 1 is a flow chart of the present invention;

[0071] Figure 2 is a block diagram of the bandwidth-adaptive sliding mode observer;

[0072] Figure 3This is the block diagram of the sensorless control of a permanent magnet synchronous linear motor based on a bandwidth adaptive sliding mode observer in the present invention. Detailed implementation manners

[0073] The present invention will be further described below with reference to the accompanying drawings:

[0074] The present invention will be described in detail below with reference to the accompanying drawings and specific implementation manners.

[0075] As Figure 2 shown, the sensorless control system of a permanent magnet synchronous linear motor based on an adaptive phase-locked loop sliding mode observer is specifically implemented according to the following steps.

[0076] Step 1: In the α-β coordinate system, obtain the voltage equation and back electromotive force equation of the permanent magnet synchronous linear motor;

[0077] Step 2: Rewrite the voltage equation in Step 1 as a current state equation, and accordingly design a sliding mode observer. After filtering out high-frequency harmonics through a low-pass filter, estimate the back electromotive force;

[0078] Step 3: As Figure 1 shown, first obtain the transfer function of the traditional orthogonal phase-locked loop. After the per-unitization of the back electromotive force, simplify the transfer function. Then, for the proportional and integral gains in the transfer function, use the stochastic gradient descent method for adaptive adjustment to obtain an optimized sensorless control system for the permanent magnet synchronous linear motor.

[0079] The following will elaborate on a sensorless control method for a permanent magnet synchronous linear motor based on an adaptive phase-locked loop sliding mode observer in the present invention through specific examples.

[0080] The sensorless control system of a permanent magnet synchronous linear motor based on an adaptive phase-locked loop sliding mode observer mainly includes four parts: a current loop, a speed loop, a sliding mode observer, and an adaptive phase-locked loop.

[0081] This system adopts the i d = 0 vector control method. The three-phase excitation currents i a , i b , i c output by the permanent magnet synchronous linear motor are measured by Hall sensors, and then after a 3s / 2s transformation, the excitation currents i α , i β in the stationary two-phase coordinate system are obtained. After a 2s / 2r transformation, the excitation currents i d , i q in the rotating two-phase coordinate system are obtained. The sliding mode observer passes the excitation voltage reference vectors u α , u β in the stationary two-phase coordinate system and the current vector i in the stationary two-phase coordinate system output by the motorα and i β Estimate the back electromotive force Then, the speed of the mover is estimated through a phase-locked loop. The difference between the estimated speed value and the speed reference value is taken, and after passing through the speed-loop PI controller, the q-axis current reference value is obtained. Then, the difference between the q-axis current reference value and the actual q-axis current value is taken, and after passing through the PI controller, the q-axis voltage reference value is obtained. The difference between the d-axis current reference value and the actual value is taken, and after passing through the PI controller, the d-axis voltage reference value is obtained, that is, the excitation voltage reference vector u in the rotating two-phase coordinate system is obtained d and u q After the 2r / 2s transformation, the excitation voltage reference vector u in the stationary two-phase coordinate system is obtained α and u β Finally, the PWM signal is output through space vector pulse width modulation to drive the motor

[0082] Step 1 is specifically as follows:

[0083] In step 1.1, the voltage equation of the permanent magnet synchronous linear motor in the α-β coordinate system is shown in Equation (22):

[0084]

[0085] In Equation (22), u α and u β are the components of the excitation voltage on the α and β axes respectively; R is the excitation resistance; i α and i β are the components of the excitation current on the α and β axes respectively; L is the excitation inductance of the permanent magnet synchronous linear motor; τ is the permanent magnet pole pitch, v is the mover linear speed, ψ f [[ID=3�]]is the permanent magnet flux linkage; θ is the mover position

[0086] Step 2 is specifically as follows:

[0087] In step 2.1, rewrite the voltage equation of the permanent magnet synchronous linear motor as a current state equation:

[0088]

[0089] In Equation (23), e α and e β are the back electromotive forces:

[0090]

[0091] In step 2.2, design a sliding mode observer from Equation (23). The observer and the control generator are as follows:

[0092]

[0093] In Equation (25), is the estimated value of the excitation current, z α , z β are the back electromotive force values estimated by the traditional sliding mode observer SMO:

[0094]

[0095] In Equation (26), sgn() is the sign function;

[0096] Subtracting Equation (25) from Equation (23) gives the current estimation error state equation:

[0097]

[0098] Construct the sliding mode surface s(x):

[0099]

[0100] According to the reachability condition of the sliding mode observer, the switching gain k in the sliding mode observer satisfies:

[0101] k > max(|e α |, |e β |) (29)

[0102] In Step 2.3, the switching function in the sliding mode observer will introduce high-frequency interference to the estimated back electromotive force during high-frequency switching, affecting the estimation accuracy. Therefore, a low-pass filter is selected to filter out the high-frequency harmonics in the estimated back electromotive force:

[0103]

[0104] In Equation (30), is the estimated value of the back electromotive force after passing through the low-pass filter, ω c = 2πf c , f c is the cut-off frequency of the low-pass filter, and s is the Laplace operator.

[0105] Step 3 is specifically as follows:

[0106] Step 3.1 Input the estimated back electromotive force information into the phase-locked loop.

[0107] The transfer function of the traditional orthogonal phase-locked loop is as follows:

[0108]

[0109] In Equation (31), kp and ki are the proportional and integral gains of the PI controller of the traditional orthogonal phase-locked loop.

[0110] Normalize the back electromotive force:

[0111]

[0112] The transfer function then becomes:

[0113]

[0114] If the fixed bandwidth of the traditional orthogonal phase-locked loop is selected too wide, its anti-interference performance will be affected. If it is selected too narrow, the phase-locked loop will respond slowly to rapid changes in speed, resulting in position estimation errors.

[0115] Step 3.2 uses the stochastic gradient descent method to adaptively adjust the orthogonal phase-locked loop bandwidth to minimize the estimation error and optimize the estimation performance. Express the PI gain coefficient as:

[0116]

[0117] In Equation (34), ξ is the damping coefficient, η is the center frequency, and l is the discrete time step.

[0118] Since the phase-locked loop bandwidth is usually related to the center frequency, the damping coefficient should be kept as a constant value during the adaptive process. Therefore:

[0119]

[0120] In Equation (35), μ is the step parameter that determines the adaptive speed, and δ[l] is the input error of the phase-locked loop PI controller.

[0121] The partial derivative solution in Equation (35) of Step 3.3 consists of two parts. The first part is:

[0122]

[0123]

[0124] To find the second part, the error must be tracked in a timely manner. At time [l - 1], the speed and position are estimated by the phase-locked loop PI controller. Rewrite the PI controller in the form of speed:

[0125]

[0126] In Equation (38), T s is the sampling time, m i is the PI integral register, and the integral can be expressed as:

[0127]

[0128] Substitute Equation (38) into Equation (39) to obtain the second part:

[0129]

[0130] Combining Equation (37) and Equation (40), the parameter adjustment formula for the adaptive orthogonal phase-locked loop can be obtained:

[0131] η[l] = η[l - 1] - μz1[l]z2[l] = η[l - 1] - Δη[l] (41)

[0132] In Equation

[41] , z2[l] has been simplified, and a T s has become part of μ

[0133] z2[l] = 2ξδ[l - 1] + T s η[l - 1](δ[l - 1] + δ[l - 2]) (42)

[0134] Through the above process, the PI gain of the phase-locked loop can be iteratively updated, adaptively adjusting the bandwidth according to the following speed, and realizing the optimization of the sensorless control performance of the permanent magnet synchronous linear motor.

[0135] In another embodiment of the present invention, a sensorless control system for a permanent magnet synchronous linear motor is provided, which can be used to implement the above-mentioned sensorless control method for a permanent magnet synchronous linear motor. Specifically, the system includes:

[0136] A model establishment module for establishing a mathematical model of the permanent magnet synchronous linear motor;

[0137] An estimation module for estimating the back electromotive force information using a sliding mode observer according to the mathematical model of the permanent magnet synchronous linear motor;

[0138] A data extraction module for adaptively adjusting the proportional-integral gain of the phase-locked loop using the stochastic gradient descent method, enabling the phase-locked loop to operate at a low bandwidth and adjusting the bandwidth in real time when the speed changes, and extracting speed and position information from the estimated back electromotive force information.

[0139] The division of modules in the embodiments of the present invention is illustrative, merely a logical function division. In actual implementation, there may be other division methods. In addition, in each embodiment of the present invention, each functional module can be integrated in a processor, or can exist separately physically, or two or more modules can be integrated in one module. The above-mentioned integrated modules can be implemented in the form of hardware or in the form of software functional modules.

[0140] In another embodiment of the present invention, a computer device is provided. The computer device includes a processor and a memory. The memory is used to store a computer program, and the computer program includes program instructions. The processor is used to execute the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, and is suitable for implementing one or more instructions. Specifically, it is suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function. The processor described in the embodiment of the present invention can be used for the operation of the sensorless control method of the permanent magnet synchronous linear motor.

[0141] In another embodiment of the present invention, a storage medium is also provided, specifically a computer-readable storage medium (Memory). The computer-readable storage medium is a memory device in the computer device and is used to store programs and data. It can be understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and, of course, the extended storage medium supported by the computer device. The computer-readable storage medium provides a storage space, and the operating system of the terminal is stored in this storage space. And, one or more instructions suitable for being loaded and executed by the processor are also stored in this storage space. These instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. One or more instructions stored in the computer-readable storage medium can be loaded and executed by the processor to implement the corresponding steps of the sensorless control method of the permanent magnet synchronous linear motor in the above embodiments.

[0142] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) that contain computer-usable program code.

[0143] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices produce means for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0144] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory produce a manufactured article including instruction means that implement the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0145] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are performed on the computer or other programmable device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 [[ID=I9]]one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0146] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that it is still possible to modify the specific implementation manners of the present invention or make equivalent replacements. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A sensorless control method for a permanent magnet synchronous linear motor, characterized in that, Including: Establish the mathematical model of the permanent magnet synchronous linear motor; Estimate the back electromotive force information using a sliding mode observer according to the mathematical model of the permanent magnet synchronous linear motor; Adopt the stochastic gradient descent method to adaptively adjust the proportional-integral gain of the phase-locked loop, make the phase-locked loop work at a low bandwidth, and adjust the bandwidth in real time when the speed changes, and extract the speed and position information from the estimated back electromotive force information; The transfer function of the quadrature phase-locked loop is as follows: In Equation (10), kp and ki are the proportional and integral gains of the PI controller of a traditional quadrature phase-locked loop; Normalize the back electromotive force: Then the transfer function becomes: Adopt the stochastic gradient descent method to adaptively adjust the proportional-integral gain of the phase-locked loop, make the phase-locked loop work at a low bandwidth: Input the estimated back electromotive force information into the phase-locked loop, adopt the stochastic gradient descent method to adaptively adjust the bandwidth of the quadrature phase-locked loop to minimize the estimation error, and express the PI gain coefficient as: In Equation (13), ξ is the damping coefficient, η is the center frequency, and l is the discrete time step; During the adaptive process, the damping coefficient should be kept as a constant value, so: In Equation (14), μ is the step parameter that determines the adaptive speed, and δ[l] is the input error of the PI controller of the phase-locked loop; The partial derivative solution in Equation (14) consists of two parts. The first part is: At time [l-1], estimate the speed and position by the PI controller of the phase-locked loop, and rewrite the PI controller in the form of speed: In formula (17), T s is the sampling time, and m i is the PI integral register, and the integral is expressed as: Substitute Equation (17) into Equation (18) to obtain the second part: Combining Equation (16) and Equation (19), obtain the parameter adjustment formula of the adaptive quadrature phase-locked loop: η[l] = η[l-1] - μz1[l]z2[l] = η[l-1] - Δη[l] (20) In Equation [20], z2[l] has been simplified, and a T s has become part of μ z2[l] = 2ξδ[l - 1] + T s η[l - 1](δ[l - 1] + δ[l - 2]) (21) After the above process, the PI gain of the phase-locked loop is iteratively updated, and the bandwidth is adaptively adjusted following the speed.

2. The sensorless control method of the permanent magnet synchronous linear motor according to claim 1, wherein, The establishment of the mathematical model of the permanent magnet synchronous linear motor includes: The voltage equation of the permanent magnet synchronous linear motor is: In Equation (1), u α , u β are the components of the excitation voltage on the α and β axes respectively; R is the excitation resistance; i α , i β are the components of the excitation current on the α and β axes respectively; L is the excitation inductance of the permanent magnet synchronous linear motor; τ is the pole pitch of the permanent magnet, v is the linear velocity of the mover, ψ f is the magnetic flux linkage of the permanent magnet; θ is the mover position.

3. The sensorless control method of the permanent magnet synchronous linear motor according to claim 1, wherein The specific process of estimating the back electromotive force information using a sliding mode observer is: Rewrite the voltage equation of the permanent magnet synchronous linear motor as a current state equation: In formula (2), e α and e β are back electromotive forces: Design a sliding mode observer from Equation (2). The observer and the control generator are as follows: In Equation (3), is the estimated value of the excitation current, and z α , z β are the back electromotive force values estimated by the traditional sliding mode observer SMO: In Equation (4), sgn() is the sign function; Subtract Equation (3) from Equation (2) to obtain the current estimation error state equation: Construct the sliding mode surface s(x): According to the reachability condition of the sliding mode observer, the switching gain k in the sliding mode observer satisfies: k > max(|e α |, |e β |) (8) The switching function in the sliding mode observer will bring high-frequency interference to the estimated back electromotive force during high-frequency switching, affecting the estimation accuracy. Therefore, a low-pass filter is selected to filter out the high-frequency harmonics in the estimated back electromotive force: In Equation (9), is the estimated back electromotive force after passing through the low-pass filter, ω c = 2πf c , f c is the cut-off frequency of the low-pass filter, and s is the Laplace operator.

4. Sensorless control system for permanent magnet synchronous linear motor, characterized in that, Including: A model establishment module for establishing the mathematical model of the permanent magnet synchronous linear motor; An estimation module for estimating the back electromotive force information using a sliding mode observer according to the mathematical model of the permanent magnet synchronous linear motor; A data extraction module for adaptively adjusting the proportional-integral gain of the phase-locked loop using the stochastic gradient descent method, making the phase-locked loop work at a low bandwidth, adjusting the bandwidth in real time when the speed changes, and extracting the speed and position information from the estimated back electromotive force information; The transfer function of the quadrature phase-locked loop is as follows: In Equation (10), kp and ki are the proportional and integral gains of the PI controller of the traditional orthogonal phase-locked loop; Normalize the back electromotive force: Then the transfer function becomes: Adopt the stochastic gradient descent method to adaptively adjust the proportional-integral gain of the phase-locked loop, make the phase-locked loop work at a low bandwidth: The estimated back electromotive force information is input into the phase-locked loop, and the random gradient descent method is used to adaptively adjust the bandwidth of the quadrature phase-locked loop to minimize the estimation error. The PI gain coefficient is expressed as: In Equation (13), ξ is the damping coefficient, η is the center frequency, and l is the discrete time step; The adaptive process should keep the damping coefficient as a constant value, so: In Equation (14), μ is the step size parameter that determines the adaptive speed, and δ[l] is the input error of the phase-locked loop PI controller; The partial derivative solution in Equation (14) consists of two parts. The first part is: At time [l-1], the speed and position are estimated by the phase-locked loop PI controller, and the PI controller is rewritten in the speed form: In Equation (17), T s is the sampling time, and m i is the PI integration register, and the integration is expressed as: Substituting Equation (17) into Equation (18), the second part is obtained: Combining Equation (16) and Equation (19), the parameter adjustment formula of the adaptive quadrature phase-locked loop is obtained: η[l] = η[l-1] - μz1[l]z2[l] = η[l-1] - Δη[l] (20) In Equation [20], z2[l] has been simplified, and a T s becomes part of μ z2[l] = 2ξδ[l - 1] + T s η[l - 1](δ[l - 1] + δ[l - 2]) (21) After the above process, the PI gain of the phase-locked loop is iteratively updated to adaptively adjust the bandwidth following the speed.

5. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, the steps of the sensorless control method for the permanent magnet synchronous linear motor according to any one of claims 1 to 3 are implemented.

6. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, the steps of the sensorless control method for the permanent magnet synchronous linear motor according to any one of claims 1 to 3 are implemented.

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