A control method and system for a permanent magnet synchronous motor based on a multi-layer sliding surface

Abstract

The application relates to the technical field of permanent magnet synchronous motor control, in particular to a permanent magnet synchronous motor control method and system based on a multilayer sliding surface, rotor position and speed data of a PMSM are acquired through an encoder, three-phase current data are read through a current sensor; a physical model of the relationship between the parameters of the PMSM and the rotor position, the rotor speed, the shaft voltage and the shaft voltage physical quantity is constructed, and the physical quantity is simplified into a state space expression for subsequent controller design; the controller is designed by constructing a higher level sliding surface on the sliding surface, the system robustness can be effectively improved, the multilayer sliding surface is designed based on the error defined sliding surface, and the controller is developed by introducing a predetermined time adjustment function, so that the tracking error of the rotor position of the PMSM converges to the vicinity of the zero domain quickly, all system variables are ensured to converge within the predetermined time, and the complexity of the controller is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of permanent magnet synchronous motor control technology, specifically to a permanent magnet synchronous motor control method and system based on multi-layer sliding surfaces. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) have been widely used in industrial drives, new energy vehicles, and even aerospace fields due to their excellent performance and fast response. However, due to factors such as parameter uncertainty, external disturbances, and unmodeled dynamics, achieving precise control remains difficult. Therefore, even in the face of uncertainty and disturbances, researching high-precision, high-performance PMSM control methods is of great significance. PMSM control methods include proportional-integral-derivative control, backstepping control, and model predictive control. Among them, sliding mode control is widely used due to its strong robustness, simple design, and low computational requirements. However, because the controller designed using sliding mode control contains a sign function, it is prone to chattering near the zero point. How to improve system robustness while reducing or even eliminating chattering has become a key research topic in the field of sliding mode control in recent years.

[0003] Changes in operating conditions, parameter perturbations caused by mechanical aging, and disturbances and uncertainties arising from different tasks or unexpected accidents can all severely affect control performance and even lead to system failure. Reducing or eliminating the impact of these uncertainties on the system can effectively improve the system's transient performance and robustness. Therefore, some scholars have proposed extended state observers, which can effectively improve the system's robustness by estimating lumped disturbances in the system. Other scholars have proposed disturbance observers, which observe and compensate for disturbances. However, both extended state observers and disturbance observers have difficulties in handling parameter uncertainties coupled with state variables.

[0004] Furthermore, in many PMSM application scenarios, the convergence time of the control system often needs to meet strict requirements. Finite-time control can ensure that the system converges to near zero within a finite time, but its convergence time is affected by the initial state and system parameters. Therefore, a fixed-time control method is proposed. This method can determine the upper bound of the convergence time. However, this method greatly increases the complexity of controller design. To address this, a permanent magnet synchronous motor control method based on multi-layer sliding surfaces is proposed. Summary of the Invention

[0005] To address the technical problems existing in the prior art, the present invention provides a control method for a permanent magnet synchronous motor based on a multi-layer sliding surface.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a control method for a permanent magnet synchronous motor based on a multi-layer sliding surface, the control method comprising the following steps:

[0007] S1, Data Acquisition: Acquire the parameters and physical quantities of the PMSM;

[0008] S2, Constructing the physical model: Constructing a physical model between the parameters and physical quantities of the PMSM, and simplifying the physical quantities into state-space expressions;

[0009] S3, Design Position Loop: Construct a multi-level preset time sliding surface for the position loop and design the reference signal for the current loop;

[0010] S4, Design an input saturation auxiliary system: Obtain the derivative of the reference signal of the current loop and design an input saturation auxiliary system;

[0011] S5, Designing the Current Loop: Construction shaft current loop and The multi-level preset time sliding surface of the shaft current loop, and the calculated... shaft voltage and Shaft voltage;

[0012] S6, Control Input: [Six] shaft voltage and The shaft voltage is converted into a three-phase voltage, which is then modulated and output to the motor driver to control the PMSM.

[0013] Preferably, step S1 specifically includes: the physical quantities include rotor position, rotor speed, shaft voltage and Shaft voltage; the number of gratings passed per unit time is obtained through an optical encoder to calculate the rotor speed of the PMSM, and the rotor speed is accumulated to obtain the current rotor position of the PMSM; the three-phase current of the PMSM is obtained through a current sensor. , , And converted to using Clarke transform shaft current and shaft current .

[0014] Preferably, step S2 specifically includes the following steps:

[0015] S21. Based on known physical laws, construct a physical model between PMSM and physical quantities, with the following expression:

[0016] ;

[0017] In the formula, For the rotor mechanical angle of PMSM, The derivative of the rotor mechanical angle, For the rotor mechanical speed, The derivative of the rotor's mechanical speed. The electric speed of the rotor, For rotational inertia, parameters The damping coefficient is... For electromagnetic torque, For load torque, for shaft current, for The derivative of the shaft current, for shaft current, for The derivative of the shaft current, for Shaft inductor, for Shaft inductor, For stator resistance, It is a permanent magnet flux linkage. for shaft voltage, for Shaft voltage;

[0018] and and Satisfying Relationships ,in, The number of pole pairs in the PMSM; and Satisfying Relationships Among them, parameters There is uncertainty, expressed as ,in, This is the nominal value. It is uncertain;

[0019] S22, the physical model simplified to state space is expressed as follows:

[0020] ;

[0021] In the formula, , , , , , , , , , , , , , ;variable For lumped disturbances, variables For variables Related uncertainties, variables For variables The derivative of the variable For variables The derivative of the variable For variables The derivative of the variable For variables The derivative of For rotor position, For the rotor mechanical speed, for shaft current, for Axis current.

[0022] Preferably, step S3 specifically includes the following steps:

[0023] S31, define the rotor position error as... Rotor speed error is And the two satisfy the relationship , ,in, The target position for the PMSM rotor. for The derivative;

[0024] S32, Design a preset time adjustment function The expression is:

[0025] ;

[0026] In the formula, This is the initial value for the preset time adjustment function; This is the final value of the preset time adjustment function; For PMSM control system operating time; The convergence time of the rotor position error is designed according to the task requirements. The PMSM control system has multiple preset time adjustment functions. For different values, preset time adjustment functions with the same form but different parameters are represented;

[0027] S33, Preset time adjustment function First derivative form for:

[0028] ;

[0029] Preset time adjustment function The second derivative form for:

[0030] ;

[0031] Define auxiliary variables ;

[0032] S34, according to step S31 and The first layer of the annular mold surface was designed. , The expression is:

[0033] ;

[0034] In the formula, variables An auxiliary variable for a preset time, in the form of: , The first derivative is in the form of ;variable For auxiliary variables in the sliding surface, variables for The derivative; parameters The gain in the first-layer position slip surface constructed based on the error is used to adjust the control effect;

[0035] S35, through the first layer of positional sliding mold surface Design the second layer of the ring-slip mold surface. , The expression is:

[0036] ;

[0037] In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter This is the gain in the second-layer position slip surface, used to adjust the control effect;

[0038] S36 approximates and compensates for the parameter and disturbance uncertainties in the PMSM by using a radial basis function neural network (RBFNN), and designs the reference signal for the current loop based on the compensated parameters.

[0039] Preferably, step S36 specifically includes the following steps:

[0040] S361, defines the lumped disturbance as Therefore, it can be known , where variables For weights, variables For basis functions, variables It is a bounded variable;

[0041] Define the approximate variable as Then its form is ,in, For the estimated weights, variables The lumped perturbation is approximated by RBFNN;

[0042] S362, according to the second layer position, the annular mold surface The reference signal form of the designed current loop is as follows:

[0043] ;

[0044] In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter and For PMSM parameters; variables The second derivative of the reference signal; variable for The derivative; parameters Gain adjusted to achieve the desired control objective;

[0045] The parameter update law for the S363 RBFNN weights is as follows:

[0046] ;

[0047] In the formula, the parameters and The gain in the basis function neural network parameter update law is used to adjust the control effect; variables For the estimated RBFNN weights, for The derivative of .

[0048] Preferably, step S4 specifically includes the following steps:

[0049] S41, obtained through command filter The derivative of the command filter is given by:

[0050] ;

[0051] In the formula, For command filter bandwidth, For the output of the command filter, for The derivative of the command filter, according to its characteristics, Alternative Use of derivatives;

[0052] S42, to prevent input saturation caused by controller limitations from rendering the system inoperable, respectively... shaft voltage and The shaft voltage design incorporates an input saturation auxiliary system to compensate for the current loop reference signal. The expression for the input saturation auxiliary system is as follows:

[0053] ;

[0054] In the formula, To control The variables of the convergence speed of the axis-assisted system; To control The variables of the convergence velocity of the axis-assisted system The output of the input saturation auxiliary system is used to compensate for the effects of input saturation on the system, and acts on... On the axis voltage; variable for The derivative of the variable; The output of the input saturation auxiliary system is used to compensate for the effects of input saturation on the system, and acts on... On the axis voltage; variable for The derivative; parameters and For PMSM parameters, , , for Shaft inductor, for Shaft inductance; variable An auxiliary variable for a preset time, in the form of: ;variable for The difference between the actual output and theoretical output of the shaft voltage is expressed in the form of: ,in, for Output of the axis voltage theory control law for The actual output of the shaft voltage after input saturation; variable for The difference between the actual output and theoretical output of the shaft voltage is expressed in the form of: ,in, for Output of the axis voltage theory control law for The actual output after the shaft voltage has been saturated by the input.

[0055] Preferably, in step S5, designing the control input q-axis voltage specifically includes the following steps:

[0056] S511, Design The control input of the shaft current loop, combined with the auxiliary variables designed in step S4 ,definition The error of the shaft current is , ;

[0057] S512, via The design obtained the first layer Shaft current sliding surface , The format is:

[0058] ;

[0059] In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter The first layer constructed based on error The gain in the shaft current sliding surface is used to adjust the control effect;

[0060] S513, based on the first layer Shaft current sliding surface The design yielded a second layer. Shaft current sliding surface , The form is:

[0061] ;

[0062] In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter For the second layer The gain in the shaft current sliding surface is used to adjust the control effect;

[0063] therefore, Control input of shaft current loop for:

[0064] ;

[0065] In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter , , and For PMSM parameters; variables The output of the filter is used to replace... The derivative; parameters Gain adjusted to achieve the desired control objective.

[0066] Preferably, in step S5, the control input is designed. The shaft voltage specifically includes the following steps:

[0067] S521, Design The control input of the shaft current loop will The reference signal for the shaft current loop is set to 0, combined with... ,definition The error of the shaft current is ,and ;

[0068] S522, via The design obtained the first layer Axial current toroidal surface , The form is:

[0069] ;

[0070] In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter The first layer constructed based on error The gain in the shaft current sliding surface is used to adjust the control effect;

[0071] S523, through the first layer Axial current toroidal surface The design yielded a second layer. Axial current toroidal surface , The form is:

[0072] ;

[0073] In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter For the second layer The gain of the shaft current slip mode is used to adjust the control effect;

[0074] therefore, Control input of shaft current loop for:

[0075] ;

[0076] In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter , and For PMSM parameters; parameters Gain adjusted to achieve the desired control objective.

[0077] Preferably, in step S6, the steps in step S5 are followed. and The actual input is calculated. shaft voltage and shaft voltage Specifically:

[0078] ;

[0079] ;

[0080] In the formula, For the saturation function, set The maximum value is ;if ,but ;if ,but ;

[0081] Then, through the Park transformation, shaft voltage and shaft voltage Converted to three-phase voltage , and Three-phase voltage , and After space vector pulse width modulation, a pulse signal is generated and output to the motor driver to control the rotor position of the PMSM.

[0082] This invention also provides a permanent magnet synchronous motor control system based on a multi-layer sliding surface, applied to the above-mentioned control method, comprising:

[0083] The data acquisition module is used to acquire the parameters and physical quantities of the PMSM.

[0084] The model building module is used to build a physical model of the relationship between the parameters and physical quantities of the PMSM, and to simplify the physical quantities into state-space expressions.

[0085] Position design module: used to construct multi-level preset time sliding surfaces for position loops and design reference signals for current loops;

[0086] An anti-saturation module is used to obtain the derivative of the reference signal of the current loop and to design an input saturation auxiliary system;

[0087] Current design module, used for construction shaft current loop and The multi-level preset time sliding surface of the shaft current loop, and the calculated... shaft voltage and Shaft voltage;

[0088] Control input module, used to input shaft voltage and The shaft voltage is converted into a three-phase voltage, which is then modulated and output to the motor driver to control the PMSM.

[0089] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0090] 1. This invention designs a controller for a PMSM control system by constructing a higher-level sliding surface. The controller designed under this design can improve the robustness, transient performance, and steady-state performance of the PMSM system. A multi-layer sliding surface is designed based on the error definition of the sliding surface, and a controller is developed by introducing a predetermined time adjustment function, so that the tracking error of the PMSM rotor position converges quickly to near the zero domain, ensuring that all system variables converge within a predetermined time, which greatly reduces the complexity of the controller.

[0091] 2. In this invention, RBFNN is used to estimate and compensate for nonlinear terms containing uncertainties, so as to reduce the impact of parameter uncertainty on the PMSM system. An input saturation auxiliary system is introduced to compensate for the reference signal, so as to prevent the controller limitation from causing input saturation problems that would prevent the system from running. This ensures that the control system can still operate even when input saturation exists. Attached Figure Description

[0092] Figure 1 This is a control architecture diagram of the present invention;

[0093] Figure 2 This is a rotor position curve of the motor in the comparative experiment of multi-level sliding mode and RBFNN of this invention;

[0094] Figure 3 This is a comparison experiment of the multi-level sliding mode and RBFNN of the present invention, showing the tracking error curves.

[0095] Figure 4 This is a comparison experiment current curve of multi-level sliding mode and RBFNN of the present invention;

[0096] Figure 5 This is a voltage curve diagram comparing the multi-level sliding mode and RBFNN experiments of this invention;

[0097] Figure 6 This is a graph showing the rotor position and rotor position error of the motor in a pre-set time comparison experiment according to the present invention.

[0098] Figure 7 This is a graph showing the current and voltage curves in a pre-set time comparison experiment of the present invention;

[0099] Figure 8 This is a graph showing the rotor position and rotor position error curve of the motor in the multi-level sliding mode comparison experiment of this invention;

[0100] Figure 9 The current and voltage curves are shown in the multi-level sliding mode comparison experiment of this invention. Detailed Implementation

[0101] The present invention will be further described below with reference to the accompanying drawings and embodiments, which illustrate the above and other technical features and advantages of the present invention. However, the following embodiments are merely preferred embodiments of the present invention and are not exhaustive.

[0102] Example:

[0103] A permanent magnet synchronous motor is used to support the platform. The tracking signal used in this embodiment is:

[0104] ;

[0105] Wherein, the load torque is This meets the requirements of most demanding industrial environments. The parameters of the permanent magnet synchronous motor are shown in Table 1.

[0106]

[0107] like Figure 1 As shown, this embodiment is a control method for a permanent magnet synchronous motor based on a multi-layer sliding surface, specifically including the following steps:

[0108] Step S1, Data Acquisition: Acquire the parameters and physical quantities of the PMSM; specifically, the physical quantities include rotor position, rotor speed, shaft voltage and Shaft voltage; the number of gratings passed per unit time is obtained through an optical encoder to calculate the rotor speed of the PMSM, and the rotor speed is accumulated to obtain the current rotor position of the PMSM; the three-phase current of the PMSM is obtained through a current sensor. , and And converted to using Clarke transform shaft current and shaft current .

[0109] Step S2, Constructing the Physical Model: Construct a physical model of the relationship between the parameters and physical quantities of the PMSM, and simplify the physical quantities into state-space expressions for subsequent controller design; specifically including the following steps:

[0110] S21. Based on known physical laws, construct a physical model between PMSM and physical quantities, with the following expression:

[0111] ;

[0112] In the formula, For the rotor mechanical angle of PMSM, The derivative of the rotor mechanical angle, For the rotor mechanical speed, The derivative of the rotor's mechanical speed. The electric speed of the rotor, For rotational inertia, parameters The damping coefficient is... For electromagnetic torque, For load torque, for shaft current, for The derivative of the shaft current, for shaft current, for The derivative of the shaft current, for Shaft inductor, for Shaft inductor, For stator resistance, It is a permanent magnet flux linkage. for shaft voltage, for Shaft voltage;

[0113] and and Satisfying Relationships ,in, The number of pole pairs in the PMSM; and Satisfying Relationships Among them, parameters There is uncertainty, expressed as ,in, This is the nominal value. It is uncertain;

[0114] S22, the physical model simplified to state space is expressed as follows:

[0115] ;

[0116] In the formula, , , , , , , , , , , , , , ;variable For lumped disturbances, variables For variables Related uncertainties, variables For variables The derivative of the variable For variables The derivative of the variable For variables The derivative of the variable For variables The derivative of For rotor position, For the rotor mechanical speed, for shaft current, for Axis current.

[0117] Step S3, Design the position loop: Construct a multi-level preset time sliding surface for the position loop and design the reference signal for the current loop; specifically including the following steps:

[0118] S31, define the rotor position error as... Rotor speed error is The two satisfy the relationship , ,in, The target position for the PMSM rotor. for The derivative;

[0119] S32, In order to ensure that the rotor position error can converge to a bounded range within a preset time, a preset time adjustment function is designed. The expression is:

[0120] ;

[0121] In the formula, This is the initial value for the preset time adjustment function; This is the final value of the preset time adjustment function; For PMSM control system operating time; The convergence time of the rotor position error is designed according to the task requirements. The PMSM control system has multiple preset time adjustment functions. For different values, preset time adjustment functions with the same form but different parameters are represented;

[0122] Preset time adjustment function First derivative form for:

[0123] ;

[0124] Preset time adjustment function The second derivative form for:

[0125] ;

[0126] Define auxiliary variables ;

[0127] S34, according to step S31 and The first layer of the annular mold surface was designed. , The expression is:

[0128] ;

[0129] In the formula, variables An auxiliary variable for a preset time, in the form of: , The first derivative is in the form of ;variable Auxiliary variables in the sliding surface for The derivative; parameters The gain in the first-layer position slip surface constructed based on the error is used to adjust the control effect;

[0130] S35, through the first layer of positional sliding mold surface Design the second layer of the ring-slip mold surface. , The expression is:

[0131] ;

[0132] In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter This is the gain in the second-layer position slip surface, used to adjust the control effect;

[0133] The second layer of position slip surface is designed by the first layer of position slip surface, and the third layer of position slip surface is designed by the second layer of position slip surface. The third layer of position slip surface and the second layer of position slip surface have the same form as the first layer of position slip surface. By analogy, multiple layers of position slip surfaces can be added to enhance the robustness of the control system.

[0134] S36, by approximating and compensating for the parameter uncertainties and disturbance uncertainties in the PMSM using a basis function neural network (RBFNN), and designing the reference signal for the current loop based on the compensated parameters, specifically:

[0135] S361, defines the lumped disturbance as Therefore, it can be known , where variables For weights, variables For basis functions, variables It is a bounded variable;

[0136] Define the approximate variable as Then its form is ,in, The estimated weights;

[0137] S362, according to the second layer position, the annular mold surface The reference signal form of the designed current loop is as follows:

[0138] ;

[0139] In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter and For PMSM parameters; variables The second derivative of the reference signal; variable for The derivative; parameters Gain adjusted to achieve the desired control objective;

[0140] The parameter update law for the S363 RBFNN weights is as follows:

[0141] ;

[0142] In the formula, the parameters and The gain in the basis function neural network parameter update law is used to adjust the control effect; variables For the estimated RBFNN weights, for The derivative of .

[0143] Step S4, Design the input saturation auxiliary system: Obtain the derivative of the reference signal of the current loop and design the input saturation auxiliary system; specifically including the following steps:

[0144] S41, Construct command filter to obtain The derivative of the command filter is given by:

[0145] ;

[0146] In the formula, For command filter bandwidth, For the output of the command filter, for The derivative of the command filter, according to its characteristics, Alternative Use of derivatives;

[0147] S42, to prevent input saturation caused by controller limitations from rendering the system inoperable, respectively... shaft voltage and The shaft voltage design incorporates an input saturation auxiliary system to compensate for the current loop reference signal. The expression for the input saturation auxiliary system is as follows:

[0148] ;

[0149] In the formula, To control The variables of the convergence speed of the axis-assisted system; To control The variables of the convergence velocity of the axis-assisted system The output of the input saturation auxiliary system is used to compensate for the effects of input saturation on the system, and acts on... On the axis voltage; variable for The derivative of the variable; The output of the input saturation auxiliary system is used to compensate for the effects of input saturation on the system, and acts on... On the axis voltage; variable for The derivative; parameters and For PMSM parameters, , , for Shaft inductor, for Shaft inductance; variable An auxiliary variable for a preset time, in the form of: ;variable for The difference between the actual output and theoretical output of the shaft voltage is expressed in the form of: ,in, for Output of the axis voltage theory control law for The actual output of the shaft voltage after input saturation; variable for The difference between the actual output and theoretical output of the shaft voltage is expressed in the form of: ,in, for Output of the axis voltage theory control law for The actual output after the shaft voltage has been saturated by the input.

[0150] Step S5, Design the current loop: Construction shaft current loop and The multi-level preset time sliding surface of the shaft current loop, and the calculated... shaft voltage and Shaft voltage;

[0151] Among them, S51 is the design control input. When dealing with shaft voltage, the specific steps include:

[0152] S511, Design the control input for the q-axis current loop, combining it with the auxiliary variable designed in step S4. ,definition The error of the shaft current is ,and ;

[0153] S512, via The design obtained the first layer Shaft current sliding surface , The format is:

[0154] ;

[0155] In the formula, variables An auxiliary variable for a preset time, in the form of: ;variable for Shaft current error; parameters The first layer constructed based on error The gain in the shaft current sliding surface is used to adjust the control effect;

[0156] S513, based on the first layer Shaft current sliding surface The design yielded a second layer. Shaft current sliding surface , The form is:

[0157] ;

[0158] In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter Second floor The gain in the shaft current sliding surface is used to adjust the control effect;

[0159] therefore, Control input of shaft current loop for:

[0160] ;

[0161] In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter , , and For PMSM parameters; variables The output of the filter is used to replace... The derivative; parameters Gain adjusted to achieve the desired control objective;

[0162] Pass through the first layer Second layer of shaft current slip surface design Axial current slip surface, through the second layer The third layer of shaft current slip surface design Axial current slip surface, third layer Axial current slip surface, second layer The shape of the shaft current slip surface and the first layer The shaft current slip surface is the same, and so on, multiple layers can be added. Axial current slip surface is used to enhance the robustness of the control system.

[0163] S52, Design Control Input When dealing with shaft voltage, the specific steps include:

[0164] S521, Design The control input of the shaft current loop will The reference signal for the shaft current loop is set to 0, combined with... The error of the d-axis current is defined as... ,and ;

[0165] S522, via The design obtained the first layer Axial current toroidal surface , The form is:

[0166] ;

[0167] In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter The first layer constructed based on error The gain in the shaft current sliding surface is used to adjust the control effect;

[0168] S523, through the first layer Axial current toroidal surface The design yielded a second layer. Axial current toroidal surface , The form is:

[0169] ;

[0170] In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter For the second layer The gain of the shaft current slip mode is used to adjust the control effect;

[0171] therefore, Control input of shaft current loop for:

[0172] ;

[0173] In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter , and For PMSM parameters; parameters Gain adjusted to achieve the desired control objective;

[0174] Pass through the first layer Second layer of shaft current slip surface design Axial current slip surface, through the second layer The third layer of shaft current slip surface design Axial current slip surface, third layer Axial current slip surface, second layer The shape of the shaft current slip surface and the first layer The shaft current slip surface is the same, and so on, multiple layers can be added. Axial current slip surface is used to enhance the robustness of the control system.

[0175] Step S6, Control Input: [The input will be...] shaft voltage and The shaft voltage is converted into a three-phase voltage, which is then modulated and output to the motor driver to control the PMSM; that is, through step S5... and The actual input is calculated. shaft voltage and shaft voltage Specifically:

[0176] ;

[0177] ;

[0178] In the formula, For the saturation function, set The maximum value is ;if ,but ;if ,but ;

[0179] Then, through the Park transformation, shaft voltage and shaft voltage Converted to three-phase voltage , and Three-phase voltage , and After space vector pulse width modulation, a pulse signal is generated and output to the motor driver to control the rotor position of the PMSM.

[0180] To verify the effectiveness of the proposed control method for permanent magnet synchronous motors based on multi-layer sliding surfaces, the following comparative experiments were conducted on a permanent magnet synchronous motor support platform.

[0181] Experiment 1: Comparative Analysis of Four Control Schemes: Group 1 did not use multi-stage sliding surfaces for controller design and did not use RBFNN to approximate parameter uncertainties; Group 2 used multi-stage sliding surfaces for controller design but did not use RBFNN to approximate parameter uncertainties; Group 3 used RBFNN to approximate parameter uncertainties but did not use multi-stage sliding surfaces for controller design; Group 4 used multi-stage sliding surfaces for controller design and used RBFNN to approximate parameter uncertainties. Under the condition that all other parameters are the same, the PMSM rotor position is as follows: Figure 2 As shown; the error between the PMSM rotor position and the target position is as follows. Figure 3 As shown; the d-axis and q-axis currents during PMSM operation are as follows: Figure 4 As shown; the d-axis voltage and q-axis voltage during PMSM operation are as follows: Figure 5 As shown.

[0182] Depend on Figure 2 and Figure 3 It can be seen that the first group, which did not use multi-level sliding surfaces for controller design and did not use RBFNN to approximate the parameter uncertainty, had an error of 45°; the second group, which used multi-level sliding surfaces for controller design but did not use RBFNN to approximate the parameter uncertainty, had an error of about 8°; the third group, which used RBFNN to approximate the parameter uncertainty but used multi-level sliding surfaces for controller design, had an error of about 5°; and the fourth group, which used multi-level sliding surfaces for controller design and used RBFNN to approximate the parameter uncertainty, had an error of about 1°. Figure 4 and Figure 5 It can be seen that the output values ​​of the controllers in the four sets of comparative tests are not significantly different.

[0183] Therefore, under similar control costs, both using multi-level sliding surfaces for controller design and using RBFNN to approximate parameter uncertainties can improve the robustness of the system, and using both will improve the robustness of the system even more.

[0184] Experiment 2: Comparative analysis of two control schemes: Group 1 uses control without pre-set time; Group 2 uses pre-set time control. Both experiments use a three-stage sliding surface for controller design and RBFNN to approximate parameter uncertainties. Under the condition that other parameters are consistent, the PMSM rotor position and the error between the PMSM rotor position and the target rotor position are as follows: Figure 4 As shown, the tracking error for the target rotor position is as follows: Figure 6 As shown, the voltage and current during PMSM operation are as follows: Figure 7 As shown.

[0185] Depend on Figure 6It can be seen that, for the first group without preset time control, the error converges to near the zero domain in about 2 seconds, and the steady-state error is within 0.3°; for the second group with preset time control, the error converges to near the zero domain in about 1 second, and the steady-state error is within 0.3°. Figure 7 It can be seen that the difference between the controller inputs of the two groups is not significant. Therefore, it can be concluded that introducing preset time control can effectively improve the system convergence speed without increasing the control cost.

[0186] Experiment 3: Comparative Analysis of Three Control Schemes: Group 1 uses a single-stage sliding surface for controller design; Group 2 uses a two-stage sliding surface; and Group 3 uses a three-stage sliding surface. All three groups introduce preset time control and use RBFNN to approximate and compensate for parameter uncertainties. Under the condition that other parameters are consistent, the PMSM rotor position and the error relative to the target position are as follows: Figure 8 As shown, the d-axis current, q-axis current, d-axis voltage, and q-axis current during PMSM operation are as follows: Figure 9 As shown.

[0187] Depend on Figure 8 It can be seen that the steady-state error of the first group of controllers designed using a first-level sliding surface is about 4°; the steady-state error of the second group of controllers designed using a second-level sliding surface is about 0.4°; and the steady-state error of the third group of controllers designed using a third-level sliding surface is about 0.2°. Figure 9 It can be seen that the input differences of the three sets of controllers are not significant.

[0188] Therefore, the robustness of the controller designed with a three-level sliding surface is better than that of the controller designed with a two-level sliding surface, and better than that of the controller designed with a single-level sliding surface. Furthermore, the robustness of the designed controller improves as the sliding surface level increases.

[0189] In summary, the method of the present invention is superior to the existing solutions in both suppressing chattering and improving convergence speed and system robustness.

[0190] The above description is merely a preferred embodiment of the present invention and is illustrative rather than restrictive. Those skilled in the art will understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, all of which will fall within the protection scope of the present invention.

Claims

1. A control method for a permanent magnet synchronous motor based on a multi-layer sliding surface, characterized in that, The permanent magnet synchronous motor control method includes the following steps: S1, Data Acquisition: Acquire the parameters and physical quantities of the PMSM; S2, Constructing the physical model: Constructing a physical model between the parameters and physical quantities of the PMSM, and simplifying the physical quantities into state-space expressions; S3, Design Position Loop: Construct a multi-level preset time sliding surface for the position loop and design the reference signal for the current loop; S4, Design an input saturation auxiliary system: Obtain the derivative of the reference signal of the current loop and design an input saturation auxiliary system; S5, Designing the Current Loop: Construction shaft current loop and The multi-level preset time sliding surface of the shaft current loop, and the calculated... shaft voltage and Shaft voltage; S6, Control Input: [Six] shaft voltage and The shaft voltage is converted into a three-phase voltage, which is then modulated and output to the motor driver to control the PMSM.

2. The permanent magnet synchronous motor control method based on multi-layer sliding surfaces as described in claim 1, characterized in that, Specifically, step S1 involves the following: the physical quantities include rotor position, rotor speed, shaft voltage and Shaft voltage; the number of gratings passed per unit time is obtained through an optical encoder to calculate the rotor speed of the PMSM, and the rotor speed is accumulated to obtain the current rotor position of the PMSM; the three-phase current of the PMSM is obtained through a current sensor. , , And converted to using Clarke transform shaft current and shaft current .

3. The permanent magnet synchronous motor control method based on multi-layer sliding surfaces as described in claim 1, characterized in that, Step S2 specifically includes the following steps: S21. Based on known physical laws, construct a physical model between PMSM and physical quantities, with the following expression: ； In the formula, For the rotor mechanical angle of PMSM, The derivative of the rotor mechanical angle, For the rotor mechanical speed, The derivative of the rotor's mechanical speed. The electric speed of the rotor, For rotational inertia, parameters The damping coefficient is... For electromagnetic torque, For load torque, for shaft current, for The derivative of the shaft current, for shaft current, for The derivative of the shaft current, for Shaft inductor, for Shaft inductor, For stator resistance, It is a permanent magnet flux chain. for shaft voltage, for Shaft voltage; and and Satisfying Relationships ,in, The number of pole pairs in the PMSM; and Satisfying Relationships Among them, parameters There is uncertainty, expressed as ,in, This is the nominal value. It is uncertain; S22, the physical model simplified to state space is expressed as follows: ； In the formula, , , , , , , , , , , , , , ;variable For lumped disturbances, variables For variables Related uncertainties, variables For variables The derivative of the variable For variables The derivative of the variable For variables The derivative of the variable For variables The derivative of For rotor position, For the rotor mechanical speed, for shaft current, for Axis current.

4. The permanent magnet synchronous motor control method based on multi-layer sliding surfaces as described in claim 1, characterized in that, Step S3 specifically includes the following steps: S31, define the rotor position error as... Rotor speed error is And the two satisfy the relationship , ,in, The target position for the PMSM rotor. for The derivative; S32, Design a preset time adjustment function The expression is: ； In the formula, This is the initial value for the preset time adjustment function; This is the final value of the preset time adjustment function; For PMSM control system operating time; The convergence time of the rotor position error is designed according to the task requirements. The PMSM control system has multiple preset time adjustment functions. For different values, preset time adjustment functions with the same form but different parameters are represented; S33, Preset time adjustment function First derivative form for: ； Preset time adjustment function The second derivative form for: ； Define auxiliary variables ; S34, according to step S31 and The first layer of the annular mold surface was designed. , The expression is: ； In the formula, variables An auxiliary variable for a preset time, in the form of: , The first derivative is in the form of ;variable For auxiliary variables in the sliding surface, variables for The derivative; parameters The gain in the first layer of position slip surface constructed based on the error; S35, through the first layer of positional sliding mold surface Design the second layer of the ring-slip mold surface. , The expression is: ； In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter This refers to the gain in the second-layer position slip surface; S36 approximates and compensates for the parameter and disturbance uncertainties in the PMSM through a radial basis function neural network, and designs the reference signal for the current loop based on the compensated parameters.

5. The permanent magnet synchronous motor control method based on multi-layer sliding surfaces as described in claim 4, characterized in that, Step S36 specifically includes the following steps: S361, define the lumped disturbance as Therefore, it can be known , where variables For weights, variables For basis functions, variables It is a bounded variable; Define the approximate variable as Then its form is ,in, For the estimated weights, variables The lumped perturbation is approximated by RBFNN; S362, according to the second layer position of the annular mold surface The reference signal form of the designed current loop is as follows: ； In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter and For PMSM parameters; variables The second derivative of the reference signal; variable for The derivative; parameters Gain adjusted to achieve the desired control objective; S363, the parameter update law for the weights of a radial basis function neural network is in the form of: ； In the formula, the parameter and The gain in the parameter update law of the basis function neural network is used to adjust the control effect; variables For the estimated RBFNN weights, for The derivative of .

6. The permanent magnet synchronous motor control method based on multi-layer sliding surfaces as described in claim 1, characterized in that, Step S4 specifically includes the following steps: S41, obtained through command filter The derivative of the command filter is given by: ； In the formula, For command filter bandwidth, For the output of the command filter, for The derivative of the command filter, according to its characteristics, Alternative Use of derivatives; S42, respectively shaft voltage and The shaft voltage design incorporates an input saturation auxiliary system to compensate for the current loop reference signal. The expression for the input saturation auxiliary system is as follows: ； In the formula, To control The variables affecting the convergence speed of the axis-assisted system; To control The variables of the convergence velocity of the axis-assisted system The output of the input saturation auxiliary system is used to compensate for the effects of input saturation on the system, and acts on... On the axis voltage; variable for The derivative of the variable; The output of the input saturation auxiliary system is used to compensate for the effects of input saturation on the system, and acts on... On the axis voltage; variable for The derivative; parameters and For PMSM parameters, , , for Shaft inductor, for Shaft inductance; variable An auxiliary variable for a preset time, in the form of: ;variable for The difference between the actual output and theoretical output of the shaft voltage is expressed in the form of: ,in, for Output of the axis voltage theory control law for The actual output of the shaft voltage after input saturation; variable for The difference between the actual output and theoretical output of the shaft voltage is expressed in the form of: ,in, for Output of the axis voltage theory control law for The actual output after the shaft voltage has been saturated by the input.

7. The permanent magnet synchronous motor control method based on multi-layer sliding surfaces as described in claim 1, characterized in that, In step S5, the control input is designed. The shaft voltage specifically includes the following steps: S511, Design The control input of the shaft current loop, combined with the auxiliary variables designed in step S4 ,definition The error of the shaft current is , ; S512, via The design obtained the first layer Shaft current sliding surface , The format is: ； In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter The first layer constructed based on error Gain in the shaft current sliding mode surface; S513, based on the first layer Shaft current sliding surface The design yielded a second layer. Shaft current sliding surface , The form is: ； In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter For the second layer Gain in the shaft current sliding mode surface; therefore, Control input of shaft current loop for: ； In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter , , and For PMSM parameters; variables The output of the filter is used to replace... The derivative; parameters Gain adjusted to achieve the desired control objective.

8. The permanent magnet synchronous motor control method based on multi-layer sliding surfaces as described in claim 1, characterized in that, In step S5, the control input is designed. The shaft voltage specifically includes the following steps: S521, Design The control input of the shaft current loop will The reference signal for the shaft current loop is set to 0, combined with... ,definition The error of the shaft current is ,and ; S522, via The design obtained the first layer Axial current toroidal surface , The form is: ； In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter The first layer constructed based on error Gain in the shaft current sliding mode surface; S523, through the first layer Axial current toroidal surface The design yielded a second layer. Axial current toroidal surface , The form is: ； In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter For the second layer Gain of the shaft current slip mode; therefore, Control input of shaft current loop for: ； In the formula, variables An auxiliary variable for a preset time, in the form of: ;parameter , and For PMSM parameters; parameters Gain adjusted to achieve the desired control objective.

9. The permanent magnet synchronous motor control method based on multi-layer sliding surfaces as described in claim 1, characterized in that, In step S6, the process described in step S5 is as follows: and The actual input is calculated. shaft voltage and shaft voltage Specifically: ； ； In the formula, Set as the saturation function The maximum value is ;if ,but ;if ,but ;set up The maximum value is ;if ,but ;if ,but ; Then, through the Park transformation, shaft voltage and shaft voltage Converted to three-phase voltage , and Three-phase voltage , and After space vector pulse width modulation, a pulse signal is generated and output to the motor driver to control the rotor position of the PMSM.

10. A permanent magnet synchronous motor control system based on multi-layer sliding surface, characterized in that, The control method applied to any one of claims 1-9 includes: The data acquisition module is used to acquire the parameters and physical quantities of the PMSM. The model building module is used to build a physical model of the relationship between the parameters and physical quantities of the PMSM, and to simplify the physical quantities into state-space expressions. Position design module: used to construct multi-level preset time sliding surfaces for position loops and design reference signals for current loops; An anti-saturation module is used to obtain the derivative of the reference signal of the current loop and to design an input saturation auxiliary system; Current design module, used for construction shaft current loop and The multi-level preset time sliding surface of the shaft current loop, and the calculated... shaft voltage and Shaft voltage; Control input module, used to input shaft voltage and The shaft voltage is converted into a three-phase voltage, which is then modulated and output to the motor driver to control the PMSM.

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