Permanent magnet synchronous motor adaptive sliding mode speed control method based on improved reaching law

Abstract

The invention discloses a permanent magnet synchronous motor adaptive sliding mode speed control method based on an improved reaching law, and belongs to the field of permanent magnet synchronous motor sliding mode speed control. A power item and a variable speed regulation function of the sliding mode surface are introduced into a constant-speed switching item and an exponential reaching item of a traditional exponential reaching law respectively, a hyperbolic sine function is used for replacing a switching function, and an improved reaching law with the fast reaching and buffeting suppression characteristics is obtained; designing a speed controller of the permanent magnet synchronous motor; designing a self-adaptive sliding mode disturbance observer independent of disturbance boundary information by adopting a double-layer self-adaptive structure, estimating total disturbance of a speed control loop, and taking an output value of the observer as speed controller compensation; the controller and the observer are applied to a permanent magnet synchronous motor vector control system. The method can effectively improve the speed control response speed and the steady-state performance of the permanent magnet synchronous motor.

Description

Technical Field

[0001] The present invention belongs to the field of sliding mode speed control of permanent magnet synchronous motors, and in particular relates to an adaptive sliding mode speed control method of permanent magnet synchronous motors based on an improved reaching law. Background Art

[0002] Permanent magnet synchronous motors (PMSMs) offer advantages over asynchronous motors, such as high power factor, simple structure, strong load capacity, and fast response speed. In recent years, they have become increasingly popular in AC servo systems for electric vehicles, CNC machine tools, robotics, and even heavy machinery. However, the long-term operation of most PMSMs in environments with complex and variable external excitation can cause internal parameter changes, leading to a combination of internal and external excitation. This requires motor control systems with fast dynamic response and strong robustness.

[0003] While the classic PI control strategy offers excellent control performance in linear systems, it suffers from large overshoot and poor disturbance immunity in nonlinear systems with multiple variables and strong coupling, such as permanent magnet synchronous motors. However, sliding mode control, due to its low model accuracy requirements and robustness to internal and external disturbances, has gained traction in various control domains. However, sliding mode control has significant drawbacks, including the potential for chattering, which in turn increases switching losses in the control system's electronic components.

[0004] As a key step in the sliding mode control algorithm, the reaching law is how the control system state variables reach the sliding mode surface and is directly related to the response speed of the sliding mode controller. Traditional exponential reaching laws suffer from the conflict between jitter suppression and reaching speed. The system's real-time disturbance is estimated through an observer and used as the compensation input for the speed controller. However, the design parameters of traditional fixed-switching-gain sliding mode disturbance observers rely on threshold information about the unknown disturbance and its derivative. Furthermore, during actual operation, permanent magnet synchronous motors are affected by matching internal and external disturbances, or the corresponding threshold information cannot be accurately measured. Furthermore, when the total internal and external disturbances decrease, the observer's estimate does not decrease, resulting in a surplus input to the system observer and increased system energy consumption.

[0005] The prior art with publication number CN111711396A provides a method for adjusting the speed loop control parameters of a permanent magnet synchronous motor based on a fractional-order sliding mode controller, which mainly relates to the field of AC motor control technology. The present invention discloses a method for adjusting the speed loop control parameters of a permanent magnet synchronous motor based on a fractional-order sliding mode controller, including the construction of a fractional-order sliding mode control surface and an intelligent algorithm to optimize and adjust the parameters of the fractional-order sliding mode controller. The present invention also designs a permanent magnet synchronous motor speed control device based on fractional-order sliding mode control. The permanent magnet synchronous motor speed control method and device based on a fractional-order sliding mode controller designed by the present invention can achieve high-performance control of the motor when there is a load disturbance in the control system of the permanent magnet synchronous motor. This control method has high requirements on computing power, the overall calculation is complex, and the accuracy needs to be improved. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, a permanent magnet synchronous motor adaptive sliding mode speed control method based on an improved reaching law is provided. Its response speed can improve the anti-interference performance of the permanent magnet synchronous motor speed control system and suppress high-frequency vibration.

[0007] To achieve the above technical objectives, the present invention proposes an adaptive sliding mode speed control method for a permanent magnet synchronous motor based on an improved reaching law, the specific steps of which are as follows:

[0008] Step 1: Use the Hall current sensor module to collect the motor three-phase current i in real time A ,i B and i C , the stator winding equivalent current i in the αβ two-phase stationary coordinate system is obtained by Clark transformation α and i β , and then the equivalent current value i of the stator winding current in the two-phase synchronous rotating dq coordinate system is obtained by Park transformation d ,i q ;

[0009] Step 2: Calculate the mechanical angular velocity ω of the motor rotor in real time through real-time sampling by the photoelectric encoder m , mechanical angle θ m and electrical angle θ e ;

[0010] Step 3: Construct an adaptive sliding mode disturbance observer to improve the anti-disturbance capability and stability of the permanent magnet synchronous motor speed control; use the adaptive sliding mode disturbance observer to calculate the rotor speed ω m Get an estimate of the total disturbance

[0011] Step 4: Construct a sliding mode speed controller based on the improved reaching law and integral sliding surface, and set the rotor target angular velocity ω m *The rotor angular velocity ω obtained by real-time sampling m The difference is input into the sliding mode controller; at the same time, the estimated value of the total disturbance is As the compensation input sliding mode controller, the q-axis current reference value i at the next moment can be obtained through the sliding mode controller. q * ;

[0012] Step 5: Current inner loop uses i d = 0 vector control strategy, calculate the current reference value i q * and the q-axis current reference value i q * The equivalent current value i of the q axis q The difference is input into the PI controller to obtain the q-axis voltage reference u of the next control cycle of the current loop. q * ; Calculate the d-axis current reference value i d * =0 and d-axis equivalent current value i d The difference is input into the PI controller to obtain the d-axis voltage reference u of the next control cycle of the current loop. d * ;

[0013] Step 6: Set the voltage reference value u of the next control cycle of the current loop d * and u q * The voltage reference value u in the αβ two-phase stationary coordinate system is obtained by Park inverse transformation α * and u β * ;

[0014] Step 7: Set the voltage reference value u of the next control cycle of the current loop α * and u β * Input to the space pulse width vector modulation SVPWM module and calculate the pulse width to generate the voltage reference value u α * and u β * The corresponding SVPWM pulse signal is applied to the control terminal of the power switch device of the inverter as the control signal of the power switch device in the inverter, thereby realizing the sliding mode speed control of the permanent magnet synchronous motor at the next moment.

[0015] Furthermore, the adaptive sliding mode disturbance observer is expressed as follows:

[0016]

[0017] in, is the mechanical angular velocity ω of the permanent magnet synchronous motor m The estimated value of is the angular velocity estimation error; is the estimated value of the total disturbance; u ASMDO is the adaptive control law of the observer, s m is the sliding surface of the observer, and the constant c m and l are the design coefficients of the adaptive sliding mode disturbance observer, respectively.

[0018] Furthermore, the total disturbance d(t) required for the adaptive sliding mode disturbance observer to calculate is described as follows:

[0019] Assume that the current equation, torque equation and mechanical motion equation of the surface-mounted permanent magnet synchronous motor in the dq coordinate system are:

[0020]

[0021] Where R is the stator phase winding resistance; ω e is the rotor electrical angular velocity; L d and L q are the dq axis inductance of the permanent magnet synchronous motor respectively; f is the permanent magnet flux; n p is the number of permanent magnet poles; T e is the electromagnetic torque; T L is the load torque; B m is the rotor damping coefficient; J is the rotor moment of inertia;

[0022] The parameters in the permanent magnet synchronous motor speed control loop and the external load change, the mechanical motion equation of the permanent magnet synchronous motor is expressed as:

[0023]

[0024] in, ψ f 0 is the nominal value of permanent magnet flux; J0 is the nominal value of moment of inertia; B m0 is the nominal value of the rotor damping coefficient; “Δ” represents the variation; the permanent magnet synchronous motor can only be controlled when the disturbance is bounded, so the total disturbance d(t) is expressed as follows:

[0025]

[0026] Where L0 and L1 are unknown positive constants, and f(t) is a continuous function.

[0027] Furthermore, the adaptive control law u in the adaptive sliding mode disturbance observer ASMDO Expressed as:

[0028]

[0029] Among them, the parameter η > 0, and ρ(t) is the time-varying switching gain of u ASMDO to adapt to the change of the total disturbance d(t) of the speed control loop. ρ(t) satisfies a double-layer adaptive structure, and the specific design is as follows

[0030]

[0031] Among them, κ0, ι, γ, and χ0 are all positive constants of undetermined parameters, and 0 < q < 1. The time constant τ > 0 determines the bandwidth of the low-pass filter ; is the approximation of the equivalent control; the design parameters ι, γ, and χ0 should satisfy the following inequalities:

[0032]

[0033] Among them, the design parameter p satisfies 0 < p < 1.

[0034] Furthermore, the process of constructing a sliding-mode speed controller based on the improved reaching law and integral sliding-mode surface is as follows:

[0035] The improved sliding-mode reaching law is expressed as:

[0036]

[0037] Among them, s is the sliding-mode surface of the sliding-mode speed controller and satisfies:

[0038]

[0039] Among them, x1 is the integral value of the motor mechanical angular velocity error, x2 is the motor mechanical angular velocity error, and c > 0 is the sliding-mode surface coefficient; the control input i of the sliding-mode speed controller after disturbance compensation by the adaptive sliding-mode disturbance observer q * is expressed as follows:

[0040]

[0041] A device for executing a motor control algorithm includes a processor and a memory. The processor is electrically connected to the memory. The memory is used to store instructions and data, and the processor is used to execute the adaptive sliding-mode speed control method for a permanent magnet synchronous motor based on the improved reaching law.

[0042] The beneficial effects are:

[0043] (1) This method designs an improved sliding-mode reaching law, which on the one hand effectively suppresses the inherent chattering in sliding-mode control, and on the other hand improves the response speed of the control.

[0044] (2) The adaptive sliding mode disturbance observer constructed by this method can estimate system disturbance information in real time without relying on accurate information about the system matching disturbance threshold. Compared with the sliding mode disturbance observer with fixed switching gain, the proposed observer has faster response speed, lower energy consumption, and more accurate estimation.

[0045] (3) This method uses the total disturbance estimation of the speed control loop as the compensation input of the sliding mode controller, achieving better speed anti-disturbance control effect and improving operation stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a block diagram of an adaptive sliding mode speed control of a permanent magnet synchronous motor based on an improved reaching law according to an embodiment of the present invention;

[0047] Figure 2 Schematic diagram of the process of adaptive sliding mode speed control of a permanent magnet synchronous motor based on an improved reaching law in an embodiment of the present invention;

[0048] Figure 3 1 is a flow chart of a sliding mode speed controller according to an embodiment of the present invention;

[0049] Figure 4 The conventional sliding mode disturbance observer (SMDO) and the adaptive sliding mode disturbance observer (ASMDO) provided in the embodiment of the present invention are used to analyze the step load T L Estimated comparison curve of SMDO; (a) is the SMDO of T L The estimated effect of ASMDO on T L Estimated effect diagram.

[0050] Figure 5 A comparison curve diagram of the control laws of the two observers provided in the embodiment of the present invention; wherein (a) is the control law u of the traditional sliding mode disturbance observer SMDO (b) is the control law u of the adaptive sliding mode disturbance observer ASMDO 's curve graph.

[0051] Figure 6 Comparison curves of the speed response when the moment of inertia mismatch occurs between the control strategy provided by an embodiment of the present invention and the PI control strategy. (a) shows the motor speed curve corresponding to the PI control strategy when the moment of inertia of the permanent magnet synchronous motor changes during operation, and (b) shows the motor speed curve corresponding to the ISMC+ASMDO control strategy proposed by the present invention when the moment of inertia of the permanent magnet synchronous motor changes during operation. DETAILED DESCRIPTION

[0052] The embodiments of the present invention are described in further detail below with reference to the accompanying drawings.

[0053] like Figure 1-2 As shown in FIG, the adaptive sliding mode speed control method of a permanent magnet synchronous motor based on an improved reaching law of the present invention is composed of an adaptive sliding mode disturbance observer (ASMDO) module, a sliding mode speed controller (SMSC) module, a current PI control module, a sensor module, a digital signal processor, an inverter, a DC power supply (Udc) and a permanent magnet synchronous motor (PMSM). The actual angular velocity ω of the permanent magnet synchronous motor is m The q-axis current iq is calculated and processed by the adaptive sliding mode disturbance observer to obtain the total disturbance estimation value of the speed control loop; the sliding mode speed controller is based on the reference angular velocity ω m * and the actual angular velocity ω m The difference between the total disturbance estimate and the q-axis current reference value i is obtained. q * ; The current loop is based on i d = 0, the reference value of the dq axis current is subtracted from the actual value, and the difference is output by the PI controller to obtain the dq axis voltage reference value; the dq axis voltage reference value is further transformed by the inverse Park transform to obtain the voltage reference value u in the αβ two-phase stationary coordinate system. α * and u β * , the control signal of the power switching device in the inverter is obtained through SVPWM; the sensor module includes a Hall current sensor, a photoelectric encoder, a temperature sensor, and a DC bus voltage detection module; the present invention relies on a discrete algorithm to implement the specific algorithm through a digital signal processor.

[0054] The present invention replaces the traditional outer-loop PI controller with a composite control structure consisting of an adaptive sliding mode observer and a sliding mode speed controller under the traditional dual-closed-loop vector control structure. The three-phase current and speed are collected by sensors and input into the adaptive sliding mode disturbance observer to estimate the internal and external disturbances of the permanent magnet synchronous motor in real time. The difference between the motor target speed and the real-time sampled motor mechanical speed is input into the sliding mode speed controller. At the same time, the adaptive sliding mode disturbance observer estimates the system disturbance in real time. The disturbance estimation result is compensated to the sliding mode speed controller to calculate the q-axis current compensation reference value i at the next moment. q * ; The inner current loop of the permanent magnet synchronous motor adopts i d =0 vector control strategy, real-time sampling of three-phase current, the sampling results are transformed by Clark and Park to obtain the dq current value i at the current moment d and i qThe difference between the reference value of the dq current at the next moment and the dq current value at the current moment is calculated. The result is passed through the PI controller, Park inverse transform, and SVPWM module to obtain the pulse signal at the next moment, control the inverter to adjust the motor operating state, and realize the speed control of the permanent magnet synchronous motor.

[0055] The axis of the coordinate transformation part is stipulated as follows: the axis of the A-phase winding in the stator ABC three-phase stationary coordinate system coincides with the α axis in the αβ two-phase stationary coordinate system; the d-axis of the rotor two-phase synchronously rotates in the dq coordinate system and coincides with the axis of the A-phase winding, and this is used as the rotor position electrical angle θ e The starting point.

[0056] The present invention discloses an adaptive sliding mode speed control method for a permanent magnet synchronous motor based on an improved reaching law, which specifically includes the following steps:

[0057] Step 1: Use the Hall current sensor module to collect the motor three-phase current i in real time A ,i B and i C Then, the stator winding equivalent current i in the αβ two-phase stationary coordinate system is obtained by Clark transformation. α and i β , the specific coordinate transformation form is

[0058]

[0059] Step 2: Calculate the mechanical angular velocity ω of the motor rotor in real time through real-time sampling by the photoelectric encoder m , mechanical angle θ m and electrical angle θ e ;

[0060] Based on the electrical angle θ obtained by sampling in step 2 e , for the stator winding equivalent current i α and i β The equivalent current value i of the stator winding current in the two-phase synchronous rotating dq coordinate system is obtained by Park transformation d ,i q The specific coordinate transformation form is

[0061]

[0062] The current equation, torque equation and mechanical motion equation of the surface-mounted permanent magnet synchronous motor in the dq coordinate system are:

[0063]

[0064] Where R is the stator phase winding resistance; ω e is the rotor electrical angular velocity; L d and L qare the dq axis inductance of the permanent magnet synchronous motor respectively; f is the permanent magnet flux; n p is the number of permanent magnet poles; T e is the electromagnetic torque; T L is the load torque; B m is the rotor damping coefficient; J is the rotor moment of inertia.

[0065] Taking into account the parameters in the permanent magnet synchronous motor speed control loop and the changes in external load, the mechanical motion equation of the permanent magnet synchronous motor can be further expressed as

[0066]

[0067] in, ψ f 0 is the nominal value of permanent magnet flux; J0 is the nominal value of moment of inertia; B m0 is the nominal value of the rotor damping coefficient; "Δ" represents the variation; for the actual control system of a permanent magnet synchronous motor, the motor can only be controlled when the disturbance is bounded. However, the threshold information of the disturbance is often difficult to obtain accurately, so the following assumption is made for the total disturbance d(t):

[0068]

[0069] Where L0 and L1 are unknown positive constants, and f(t) is a continuous function.

[0070] Step 3: In order to improve the anti-disturbance performance and stability of the speed control system, an adaptive sliding mode disturbance observer is designed. The specific design form is as follows

[0071]

[0072] in, is the mechanical angular velocity ω of the permanent magnet synchronous motor m The estimated value of is the angular velocity estimation error; is the estimated value of the total disturbance; u ASMDO is the adaptive control law of the observer, s m is the sliding surface of the observer, and the constant c m and l are the observer design coefficients respectively.

[0073] The adaptive control law u in the adaptive sliding mode disturbance observer (1) ASMDO , specifically expressed as

[0074]

[0075] Among them, the parameter η>0. ρ(t) is u ASMDOThe time-varying switching gain is used to adapt to the change of the total disturbance d(t) of the speed control loop. ρ(t) satisfies a double-layer adaptive structure, and the specific design is as follows

[0076]

[0077] Among them, κ0, ι, γ, and χ0 are all positive constants to be determined, and 0 < q < 1. The time constant τ > 0 determines the bandwidth of the low-pass filter ; is an approximation of the equivalent control; the design parameters ι, γ, and χ0 should satisfy the following inequalities

[0078]

[0079] Among them, the design parameter p satisfies 0 < p < 1.

[0080] By combining the rotor mechanical motion equations in Eqs. (4) and (6), the following dynamic equation of the motor speed estimation error can be obtained

[0081]

[0082] Construct the Lyapunov function V1 = 0.5s m2 , prove that the sliding surface s m will eventually converge to 0, that is, the speed estimation error is 0. Take the first derivative of V1 and substitute the sliding surface s in Eq. (6) m and Eq. (10):

[0083]

[0084] It can be seen from this that when the sliding surface s m = 0, there is

[0085]

[0086] Based on the concept of equivalent control, it can be seen from Eq. (12) that at this time, the disturbance estimation error is equivalent to ε m (t)sgn(s m ). Therefore, it is necessary to further prove that the disturbance estimation error will eventually converge to a bounded domain containing .

[0087] From the assumption of the total disturbance d(t) in Eq. (5), combine the dynamic function of the disturbance estimation in Eq. (6) and solve to get

[0088]

[0089] Among them, C is a constant; by reasonably designing the parameter l, the system disturbance estimation error It eventually converges to 0.

[0090] Therefore, the design of the adaptive sliding mode disturbance observer is reasonable.

[0091] Step 4: Design a sliding mode controller based on the improved reaching law and integral sliding surface, and set the rotor target angular velocity ω m * The rotor angular velocity ω obtained by real-time sampling in step 2 m The difference is used as the input of the sliding mode controller; at the same time, the estimated value of the total disturbance obtained in step 3 is As the compensation input, the q-axis current reference value i is obtained through the output of the sliding mode controller. q * .

[0092] The improved sliding mode reaching law can be expressed as

[0093]

[0094] Where s is the sliding surface of the speed controller and satisfies

[0095]

[0096] Among them, x1 and x2 are system state variables, and c>0 is the sliding surface coefficient. The control input i of the sliding mode speed controller is q * The design is as follows

[0097]

[0098] The perturbation estimation error obtained in step 3 Finally, the conclusion that it converges to 0 is further constructed, and the Lyapunov function V2=0.5s is constructed. 2 , calculate its first-order derivative, and substitute it into equations (15) and (16) to prove the stability of the invented sliding mode speed controller

[0099]

[0100] According to Lyapunov's stability theorem, the designed sliding mode speed controller is stable.

[0101] The specific flow chart of the sliding mode speed controller constructed based on formula (16) is as follows: Figure 3 shown.

[0102] Step 5: Current inner loop uses i d = 0 vector control strategy, calculate the d-axis current reference value i d * =0 and the d-axis current i collected in step 1 d The difference is used as the input of the d-axis current PI controller to obtain the d-axis voltage reference ud * ; The q-axis current reference value i in equation (16) q *与 The q-axis current i collected in step 1 q The difference is used as the input of the q-axis current PI controller to obtain the q-axis voltage reference u q * ;

[0103] Step 6: Set the motor rotation angle θ obtained in step 1 e , the dq axis voltage reference value u obtained in step 5 d * and u q * The voltage reference value u in the αβ two-phase stationary coordinate system is obtained by Park inverse transformation α * and u β * ; The specific coordinate transformation form is

[0104]

[0105] Step 7: Set the voltage reference value u in the αβ two-phase stationary coordinate system in step 6 to α * and u β * Input to the space pulse width vector modulation (SVPWM) module and calculate the pulse width to generate the voltage reference value u α * and u β * The corresponding SVPWM pulse signal is used as the control signal for the power switching device in the inverter;

[0106] Step 8: Apply the SVPWM pulse signal generated in step 7 to the control terminal of the power switch device of the inverter, drive it to turn on or off according to the preset timing, and generate a three-phase voltage on the stator winding of the permanent magnet synchronous motor; the electromagnetic torque generated by this voltage adjusts the rotor speed so that the actual angular velocity of the motor ω m Tracking angular velocity reference value ω m * , and finally realize the sliding mode speed control of permanent magnet synchronous motor.

[0107] This paper proposes an adaptive sliding-mode speed control method for a permanent magnet synchronous motor based on an improved reaching law. This improved sliding-mode reaching law ensures that the system state rapidly approaches the sliding-mode surface while effectively suppressing chattering. Furthermore, an adaptive sliding-mode disturbance observer accurately estimates the total disturbance without relying on the total disturbance threshold information in the speed control loop. By inputting the disturbance estimation and compensation into the sliding-mode controller, the response speed and steady-state performance of the permanent magnet synchronous motor's speed control are ultimately improved.

[0108] Example

[0109] The adaptive sliding mode speed control method of the permanent magnet synchronous motor based on the improved reaching law of the present invention is simulated and verified.

[0110] The present invention is directed to the robust speed control of permanent magnet synchronous motors, wherein the speed outer loop adopts a composite control structure consisting of a sliding mode speed controller based on an improved reaching law and an adaptive sliding mode disturbance observer. The disturbance observer estimates the internal and external disturbances of the system in real time and feeds the estimation results to the sliding mode speed controller through a feedforward compensation structure to obtain the final q-axis current reference. This improves the response speed and robustness of the speed control. In order to verify the effectiveness of the control strategy of the present invention, simulation verification is carried out based on the MATLAB / Simulink simulation platform. The specific simulation results are shown in the figure. Figures 4 to 6 shown.

[0111] Table 1 Permanent magnet synchronous motor parameters

[0112]

[0113] Figure 4 (a) is the traditional sliding mode observer (SMDO), Figure 4 (b) is the adaptive sliding mode observer (AMDO) of the present invention for the step load (T L ) estimation effect. When the load of the permanent magnet synchronous motor changes, both sliding mode observers (traditional sliding mode observer and adaptive sliding mode observer) can effectively estimate the real-time load, but the adaptive sliding mode observer has smaller estimation fluctuations and is closer to the actual load information.

[0114] Figure 5 The corresponding observer control law for the traditional sliding mode observer and the adaptive sliding mode observer in the present invention when estimating step load. Figure 5 In (a), the traditional sliding mode observer has a constant switching gain, so when the external load changes, the control law u of the traditional sliding mode observer SMDO The boundary value is a fixed value and will not change with the change of disturbance. Figure 5 The adaptive sliding mode disturbance observer proposed in the present invention adjusts its control law u according to the change of disturbance. ASMDOThis can effectively reduce the system's energy consumption and improve hardware reliability.

[0115] Figure 6 When the permanent magnet synchronous motor is running at a constant speed, when the system has an inertia mismatch, the speed control curves of the PI controller and the control strategy ISMC+ASMDO proposed in this invention are compared. Obviously, Figure 6 As shown in (a), when the motor has a 2-fold and 0.5-fold moment of inertia mismatch, the PI control strategy has poor robustness, resulting in significant overshoot and a longer settling time. Figure 6 The proposed control strategy, ISMC+ASMDO, shown in (b), achieves a shorter speed stabilization time and significantly lower maximum overshoot than the PI control strategy. The simulation results of this embodiment demonstrate that the proposed sliding-mode speed control method for permanent magnet synchronous motors, based on an adaptive sliding-mode observer and an improved reaching law, offers faster response and enhanced disturbance immunity.

Claims

1. An adaptive sliding mode speed control method for a permanent magnet synchronous motor based on an improved reaching law, characterized in that: The specific steps are as follows: Step 1: Use the Hall current sensor module to collect the motor three-phase current i in real time A ,i B and i C , the stator winding equivalent current i in the αβ two-phase stationary coordinate system is obtained by Clark transformation α and i β , and then the equivalent current value i of the stator winding current in the two-phase synchronous rotating dq coordinate system is obtained by Park transformation d ,i q ; Step 2: Calculate the mechanical angular velocity ω of the motor rotor in real time through real-time sampling by the photoelectric encoder m , mechanical angle θ m and electrical angle θ e ; Step 3: Construct an adaptive sliding mode disturbance observer to improve the anti-disturbance capability and stability of the permanent magnet synchronous motor speed control; use the adaptive sliding mode disturbance observer to calculate the rotor speed ω m Get an estimate of the total disturbance Step 4: Construct a sliding mode speed controller based on the improved reaching law and integral sliding surface, and set the rotor target angular velocity ω m * The rotor angular velocity ω obtained by real-time sampling m The difference is input into the sliding mode controller; at the same time, the estimated value of the total disturbance is As the compensation input sliding mode controller, the q-axis current reference value i at the next moment can be obtained through the sliding mode controller. q * ; Step 5: Current inner loop uses i d = 0 vector control strategy, calculate the current reference value i q * and the q-axis current reference value i q * The equivalent current value i of the q axis q The difference is input into the PI controller to obtain the q-axis voltage reference u of the next control cycle of the current loop. q * ; Calculate the d-axis current reference value i d * =0 and d-axis equivalent current value i d The difference is input into the PI controller to obtain the d-axis voltage reference u of the next control cycle of the current loop. d * ; Step 6: Set the voltage reference value u of the next control cycle of the current loop d * and u q * The voltage reference value u in the αβ two-phase stationary coordinate system is obtained by Park inverse transformation α * and u β * ; Step 7: Set the voltage reference value u of the next control cycle of the current loop α * and u β * Input to the space pulse width vector modulation SVPWM module and calculate the pulse width to generate the voltage reference value u α * and u β * The corresponding SVPWM pulse signal is applied to the control terminal of the power switch device of the inverter as the control signal of the power switch device in the inverter, thereby realizing the sliding mode speed control of the permanent magnet synchronous motor at the next moment.

2. The adaptive sliding mode speed control method for a permanent magnet synchronous motor based on an improved reaching law according to claim 1, characterized in that: The adaptive sliding mode disturbance observer is expressed as follows: in, is the mechanical angular velocity ω of the permanent magnet synchronous motor m The estimated value of is the angular velocity estimation error; is the estimated value of the total disturbance; u ASMDO is the adaptive control law of the observer, s m is the sliding surface of the observer, and the constant c m and l are the design coefficients of the adaptive sliding mode disturbance observer, respectively.

3. The adaptive sliding mode speed control method for a permanent magnet synchronous motor based on an improved reaching law according to claim 2, characterized in that: The total disturbance d(t) required for calculation by the adaptive sliding mode disturbance observer is described as follows: Assume that the current equation, torque equation and mechanical motion equation of the surface-mounted permanent magnet synchronous motor in the dq coordinate system are: Where R is the stator phase winding resistance; ω e is the rotor electrical angular velocity; L d and L q are the dq axis inductance of the permanent magnet synchronous motor respectively; f is the permanent magnet flux; n p is the number of permanent magnet poles; T e is the electromagnetic torque; T L is the load torque; B m is the rotor damping coefficient; J is the rotor moment of inertia; The parameters in the permanent magnet synchronous motor speed control loop and the external load change, the mechanical motion equation of the permanent magnet synchronous motor is expressed as: in, ψ f 0 is the nominal value of permanent magnet flux; J0 is the nominal value of moment of inertia; B m0 is the nominal value of the rotor damping coefficient; "Δ" represents the variation; the permanent magnet synchronous motor can only be controlled when the disturbance is bounded, so the total disturbance d(t) is expressed as follows: Where L0 and L1 are unknown positive constants, and f(t) is a continuous function.

4. The adaptive sliding mode speed control method for a permanent magnet synchronous motor based on an improved reaching law according to claim 2, characterized in that: The adaptive control law u in the adaptive sliding mode disturbance observer ASMDO Expressed as: Among them, the parameter η>0, ρ(t) is u ASMDO The time-varying switching gain is used to adapt to the change of the total disturbance d(t) of the speed control loop. ρ(t) satisfies the double-layer adaptive structure. The specific design is as follows where κ0, ι, γ, and χ0 are undetermined parameters that are all positive constants, 0 < q < 1, and the time constant τ > 0 determines the bandwidth of the low-pass filter ; is an approximation of the equivalent control; the design parameters ι, γ, and χ0 should satisfy the following inequalities: Among them, the design parameter p satisfies 0 <p<1。 5. The adaptive sliding mode speed control method for a permanent magnet synchronous motor based on an improved reaching law according to claim 1, characterized in that: The process of constructing a sliding mode speed controller based on the improved reaching law and integral sliding surface is as follows: The improved sliding mode reaching law is expressed as: Where s is the sliding mode surface of the sliding mode speed controller and satisfies: Among them, x1 is the integral value of the motor mechanical angular velocity error, x2 is the motor mechanical angular velocity error, c>0 is the sliding surface coefficient; the control input i of the sliding mode speed controller after the adaptive sliding mode disturbance observer is compensated for the disturbance q * It is expressed as follows:

6. A motor control algorithm execution device, characterized in that: It includes a processor and a memory, the processor is electrically connected to the memory, the memory is used to store instructions and data, and the processor is used to execute the permanent magnet synchronous motor adaptive sliding mode speed control method based on the improved reaching law as described in any one of claims 1-5.

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