Sliding Mode Control Method for Permanent Magnet Synchronous Motor Based on a New Variable Speed Exponential Reaching Law

Abstract

The present invention discloses a sliding mode control method for a permanent magnet synchronous motor based on a novel variable-speed exponential reaching law, which relates to the technical field of motor control and includes: S1, establishing a state-space mathematical model of the permanent magnet synchronous motor based on the d-q synchronous rotating coordinate system; S2, establishing a sliding mode control law of the permanent magnet synchronous motor according to the state-space mathematical model of the permanent magnet synchronous motor; S3, obtaining the sliding mode control result of the permanent magnet synchronous motor based on the Lyapunov function by using the sliding mode control law of the permanent magnet synchronous motor. The novel variable-speed exponential reaching law sliding mode control proposed by the present invention reduces the chattering of the system, shortens the time required for the system state to reach the sliding mode surface, and has fast transient response and strong robust anti-interference ability.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and particularly to a sliding mode control method for a permanent magnet synchronous motor based on a novel variable-speed exponential reaching law. Background Art

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in industrial and consumer applications, such as robotic arms and printers, due to their low manufacturing cost and good open-loop performance. However, a PMSM is also a complex control object with multiple variables, strong coupling, nonlinearity, and variable parameters. As a nonlinear control method widely applied to PMSMs, sliding mode controllers have received extensive attention. The core idea is to drive the system dynamics to a low-order sliding mode surface through discontinuous switching control. However, the high switching gain in sliding mode control will cause significant chattering phenomena. In addition, most of the currently adopted sliding mode control methods cannot well balance chattering and robustness, and there are also complex design problems. Summary of the Invention

[0003] The object of the present invention is to propose a sliding mode control method for a permanent magnet synchronous motor based on a novel variable-speed exponential reaching law, which combines an enhanced reaching law with a sliding mode surface that adapts to changes in the sliding mode surface and system state through a new sliding mode reaching law to reduce chattering and minimize the reaching time.

[0004] To achieve the above object, the present invention provides a sliding mode control method for a permanent magnet synchronous motor based on a novel variable-speed exponential reaching law, including the following steps:

[0005] S1. Establish a state-space mathematical model of the permanent magnet synchronous motor based on the d-q synchronous rotating coordinate system;

[0006] S2. Establish a sliding mode control law of the permanent magnet synchronous motor according to the state-space mathematical model of the permanent magnet synchronous motor;

[0007] S3. Obtain the sliding mode control result of the permanent magnet synchronous motor based on the sliding mode control law of the permanent magnet synchronous motor using the Lyapunov function.

[0008] Optionally, establishing a state-space mathematical model of the permanent magnet synchronous motor based on the d-q synchronous rotating coordinate system includes:

[0009] S1-1. Establish the d-axis voltage, q-axis voltage, and torque equations of the stator of the permanent magnet synchronous motor during synchronous rotation based on the d-q synchronous rotating coordinate system;

[0010] S1-2. Obtain the state-space mathematical model of the permanent magnet synchronous motor according to the d-axis voltage, q-axis voltage, and torque equations of the stator of the permanent magnet synchronous motor during synchronous rotation.

[0011] Optionally, the calculation formulas for the d-axis voltage, q-axis voltage, and torque equation of the permanent magnet synchronous motor stator during synchronous rotation are as follows:

[0012]

[0013] Among them, i d is the stator current along the d-axis, t is time, L d is the inductance on the d-axis, u d is the stator voltage on the d-axis, R s is the stator resistance, ω e is the electrical angular velocity, L q is the inductance on the q-axis, i q is the stator current along the q-axis, u q is the stator voltage on the q-axis, Ψ f is the permanent magnet flux linkage, ω m is the mechanical angular velocity, J is the moment of inertia of the load, T e is the electromagnetic torque, B a is the viscous coefficient of the load, T L is the load torque, p is the number of pole pairs of the motor.

[0014] Optionally, obtaining the state space mathematical model of the permanent magnet synchronous motor according to the d-axis voltage, q-axis voltage, and torque equation of the permanent magnet synchronous motor stator during synchronous rotation includes:

[0015] S1-2-1. Perform rotor magnetic field orientation control according to the d-axis voltage, q-axis voltage, and torque equation of the permanent magnet synchronous motor stator during synchronous rotation to obtain rotor magnetic field orientation control information;

[0016] S1-2-2. Determine the state variables of the permanent magnet synchronous motor;

[0017] S1-2-3. Obtain the state space equation of the permanent magnet synchronous motor according to the state variables of the permanent magnet synchronous motor and the rotor magnetic field orientation control information as the state space mathematical model of the permanent magnet synchronous motor.

[0018] Optionally, the calculation formula of the state - space equation of the permanent - magnet synchronous motor is as follows:

[0019]

[0020] Wherein, and are respectively x 1 x and the first - order derivative function of 2. , , x 1 is the speed error of the permanent - magnet synchronous motor, x 2 is x the first - order derivative function of 1. ω ref is the reference speed of the permanent - magnet synchronous motor, ω m is the mechanical angular velocity, is the first - order derivative of the mechanical angular velocity, D is the coefficient of the control input, u is the control input of the permanent - magnet synchronous motor and is the output of the sliding - mode controller.

[0021] Optionally, establishing the sliding - mode control law of the permanent - magnet synchronous motor according to the state - space mathematical model of the permanent - magnet synchronous motor includes:

[0022] S2 - 1. Obtain the new variable - speed exponential reaching law and the sliding - mode surface function of the speed - loop sliding - mode controller of the permanent - magnet synchronous motor;

[0023] S2 - 2. Obtain the sliding - mode control law of the permanent - magnet synchronous motor by using the new variable - speed exponential reaching law and the sliding - mode surface function of the speed - loop sliding - mode controller of the permanent - magnet synchronous motor according to the state - space mathematical model of the permanent - magnet synchronous motor.

[0024] Optionally, the calculation formula of the new variable - index reaching law of the speed - loop sliding - mode controller of the permanent - magnet synchronous motor is as follows:

[0025]

[0026] Wherein, is the first - order derivative of the sliding - mode surface, ε is the coefficient of the constant - speed reaching term, F ( x, t ) is the additional function of the variable - speed reaching term, x is the state variable of the permanent - magnet synchronous motor system, t is the time, tanh(▪) is the additional function of the variable - index reaching term, s is the sliding - mode surface function, k is the coefficient of the exponential reaching term, G ( s ) is the additional function of the variable - index reaching term,α is a constant.

[0027] Optionally, the calculation formula of the sliding mode surface function of the permanent magnet synchronous motor speed loop sliding mode controller is as follows:

[0028]

[0029] Where, s is the sliding mode surface function, C is a constant greater than zero, x 1 is the speed error of the permanent magnet synchronous motor, x 2 is x the first derivative function of 1.

[0030] Optionally, the calculation formula of the sliding mode control law of the permanent magnet synchronous motor is as follows:

[0031]

[0032] Where, i q_NewEAL is the output of the sliding mode controller, D is the coefficient of the control input, t is the time, C is a constant greater than zero, x 1 is the speed error of the permanent magnet synchronous motor, ε is the coefficient of the constant speed approaching term, F ( x, t ) is the additional function of the variable speed approaching term, x is the state variable of the permanent magnet synchronous motor system, tanh(▪) is the additional function of the variable exponent approaching term, s is the sliding mode surface function, k is the exponent approaching term coefficient, G ( s ) is the additional function of the variable exponent approaching term.

[0033] Optionally, the permanent magnet synchronous motor sliding mode control result obtained by using the sliding mode control law of the permanent magnet synchronous motor based on the Lyapunov function includes:

[0034] S3-1. Construct a Lyapunov function according to the sliding mode surface function of the permanent magnet synchronous motor speed loop sliding mode controller;

[0035] S3-2. Based on the Lyapunov function, obtain the derivative value of the Lyapunov function according to the state space mathematical model of the permanent magnet synchronous motor as the permanent magnet synchronous motor sliding mode control result.

[0036] Compared with the closest prior art, the beneficial effects of the present invention are:

[0037] The new sliding mode reaching law of the present invention combines the enhanced reaching law with a sliding mode surface that adapts to changes in the sliding mode surface and system state, reducing chattering and minimizing the reaching time; in the reaching law of the present invention, the sign function that causes chattering is replaced by the hyperbolic tangent function, and additional functions of variable speed reaching terms and variable exponent reaching terms are added. While reducing chattering, it has strong dynamic performance and robust anti-interference ability for uncertain speeds. Description of the Drawings

[0038] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0039] Figure 1 It is a flowchart of the sliding mode control method for a permanent magnet synchronous motor based on the new variable speed exponential reaching law in an embodiment of the present invention;

[0040] Figure 2 It is a schematic diagram of the implementation principle of the sliding mode control method for a permanent magnet synchronous motor proposed in an embodiment of the present invention;

[0041] Figure 3 It is a rotational speed comparison diagram of the traditional proportional integral control method with different reference speeds proposed in an embodiment of the present invention;

[0042] Figure 4 It is a rotational speed comparison diagram of the sliding mode control method with the new variable speed exponential reaching law with different reference speeds proposed in an embodiment of the present invention;

[0043] Figure 5 It is a rotational speed comparison diagram of the sliding mode control method with the traditional exponential reaching law with different reference speeds proposed in an embodiment of the present invention;

[0044] Figure 6 It is a rotational speed comparison diagram of the traditional proportional integral control method at the time of rotational speed mutation proposed in an embodiment of the present invention;

[0045] Figure 7 It is a rotational speed comparison diagram of the sliding mode control method with the traditional exponential reaching law and the traditional sliding mode surface at the time of rotational speed mutation proposed in an embodiment of the present invention;

[0046] Figure 8 It is a rotational speed comparison diagram of the sliding mode control method with the new variable speed exponential reaching law and the traditional sliding mode surface at the time of rotational speed mutation proposed in an embodiment of the present invention. Detailed Embodiments

[0047] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0048] The terms used in the embodiments of the present invention are only for explaining the specific embodiments of the present invention, rather than aiming to limit the present invention.

[0049] Embodiment 1: As Figure 1 shown, the embodiment of the present invention provides a sliding mode control method for a permanent magnet synchronous motor based on a novel variable speed exponential reaching law, including the following steps:

[0050] S1. Establish a state space mathematical model of the permanent magnet synchronous motor based on the d-q synchronous rotating coordinate system;

[0051] S2. Establish a sliding mode control law of the permanent magnet synchronous motor according to the state space mathematical model of the permanent magnet synchronous motor;

[0052] S3. Obtain the sliding mode control result of the permanent magnet synchronous motor based on the Lyapunov function using the sliding mode control law of the permanent magnet synchronous motor.

[0053] S1 specifically includes:

[0054] S1-1. Establish the d-axis voltage, q-axis voltage, and torque equations of the stator of the permanent magnet synchronous motor during synchronous rotation based on the d-q synchronous rotating coordinate system;

[0055] S1-2. Obtain the state space mathematical model of the permanent magnet synchronous motor according to the d-axis voltage, q-axis voltage, and torque equations of the stator of the permanent magnet synchronous motor during synchronous rotation.

[0056] The calculation formulas of the d-axis voltage, q-axis voltage, and torque equations of the stator of the permanent magnet synchronous motor during synchronous rotation are as follows:

[0057]

[0058] where i d is the stator current along the d-axis, t is the time, L d is the inductance on the d-axis, u d is the stator voltage on the d-axis, R s is the stator resistance, ωe is the electrical angular velocity, L q is the inductance on the q-axis, i q is the stator current along the q-axis, u q is the stator voltage on the q-axis, Ψ f is the permanent magnet flux linkage, ω m is the mechanical angular velocity, J is the moment of inertia of the load, T e is the electromagnetic torque, B a is the viscous coefficient of the load, T L is the load torque, p is the number of pole pairs of the motor.

[0059] S1-2 specifically includes:

[0060] S1-2-1. Obtain the rotor magnetic field orientation control information through rotor magnetic field orientation control according to the d-axis voltage, q-axis voltage and torque equation of the permanent magnet synchronous motor stator during synchronous rotation;

[0061] S1-2-2. Determine the state variables of the permanent magnet synchronous motor;

[0062] S1-2-3. Obtain the state space equation of the permanent magnet synchronous motor as the state space mathematical model of the permanent magnet synchronous motor according to the state variables of the permanent magnet synchronous motor and the rotor magnetic field orientation control information.

[0063] The calculation formula of the state space equation of the permanent magnet synchronous motor is as follows:

[0064]

[0065] Among them, 、 are respectively x 1、 x the first-order derivative functions of 2, , , x 1 is the speed error of the permanent magnet synchronous motor, x 2 is x the first-order derivative function of 1, ω ref is the reference speed of the permanent magnet synchronous motor, ω m is the mechanical angular velocity, is the first derivative of the mechanical angular velocity, D is the coefficient of the control input, uIt is the control input of the permanent magnet synchronous motor and the output of the sliding mode controller.

[0066] S2 specifically includes:

[0067] S2-1. Obtain the new variable speed exponential reaching law and sliding mode surface function of the permanent magnet synchronous motor speed loop sliding mode controller;

[0068] S2-2. According to the state space mathematical model of the permanent magnet synchronous motor, use the new variable speed exponential reaching law and sliding mode surface function of the permanent magnet synchronous motor speed loop sliding mode controller to obtain the sliding mode control law of the permanent magnet synchronous motor.

[0069] The calculation formula of the new variable index reaching law of the permanent magnet synchronous motor speed loop sliding mode controller is as follows:

[0070]

[0071] Where, is the first derivative of the sliding mode surface, ε is the coefficient of the constant speed reaching term, F ( x, t ) is the additional function of the variable speed reaching term, x is the state variable of the permanent magnet synchronous motor system, t is the time, tanh(▪) is the additional function of the variable index reaching term, s is the sliding mode surface function, k is the exponential reaching term coefficient, G ( s ) is the additional function of the variable index reaching term, α is a constant.

[0072] The calculation formula of the sliding mode surface function of the permanent magnet synchronous motor speed loop sliding mode controller is as follows:

[0073]

[0074] Where, s is the sliding mode surface function, C is a constant greater than zero, x 1 is the speed error of the permanent magnet synchronous motor, x 2 is x The first derivative function of 1.

[0075] The calculation formula of the sliding mode control law of the permanent magnet synchronous motor is as follows:

[0076]

[0077] Where, i q_NewEAL is the output of the sliding mode controller, D is the coefficient of the control input,t is time, C is a constant greater than zero, x 1 is the speed error of the permanent magnet synchronous motor, ε is the coefficient of the constant speed approaching term, F ( x, t ) is the additional function of the variable speed approaching term, x is the state variable of the permanent magnet synchronous motor system, and tanh(▪) is the additional function of the variable exponential approaching term, s is the sliding mode surface function, k is the exponential approaching term coefficient, G ( s ) is the additional function of the variable exponential approaching term.

[0078] S3 specifically includes:

[0079] S3-1. Construct a Lyapunov function according to the sliding mode surface function of the permanent magnet synchronous motor speed loop sliding mode controller;

[0080] S3-2. Based on the Lyapunov function, obtain the derivative value of the Lyapunov function as the sliding mode control result of the permanent magnet synchronous motor according to the state space mathematical model of the permanent magnet synchronous motor.

[0081] Embodiment 2: The embodiment of the present invention provides a sliding mode control method for a permanent magnet synchronous motor based on a novel variable speed exponential approaching law, including: establishing a mathematical model of the permanent magnet synchronous motor in the d-q synchronous rotating coordinate system; designing a sliding mode controller for the speed loop of the permanent magnet synchronous motor, including designing a novel variable speed exponential approaching law and a sliding mode surface function, and deriving a sliding mode control law based on this approaching law; performing a stability analysis on the sliding mode controller to prove that the sliding mode controller is stable under the sliding mode control of the novel variable speed exponential approaching law.

[0082] To establish the mathematical model of the permanent magnet synchronous motor in the d-q synchronous rotating coordinate system, first, the d-q axis voltage and torque equations of the stator of the permanent magnet synchronous motor during synchronous rotation are established, and the d-q axis voltage and torque equations are as follows:

[0083]

[0084] Among them, i d is the stator current along the d axis, t is time, L d is the inductance on the d axis, u d is the stator voltage on the d axis, R s is the stator resistance, ω e is the electrical angular velocity, Lq is the inductance on the q-axis, i q is the stator current along the q-axis, u q is the stator voltage on the q-axis, Ψ f is the permanent magnet flux linkage, ω m is the mechanical angular velocity, J is the moment of inertia of the load, T e is the electromagnetic torque, B a is the viscous coefficient of the load, T L is the load torque, p is the number of pole pairs of the motor.

[0085] Take i d = 0 for the rotor field-oriented control method, then obtain the rotor field-oriented control information, that is, equations (2) and (3) become:

[0086]

[0087] Then, set the state space equation of the permanent magnet synchronous motor according to the above equations.

[0088] Specifically, first determine the state variables of the permanent magnet synchronous motor system:

[0089] (7)

[0090] (8)

[0091] Among them, x 1 is the speed error of the permanent magnet synchronous motor, x 2 is x the first derivative function of 1, ω ref is the reference speed of the permanent magnet synchronous motor, usually a constant, is x the first derivative of 1, is the first derivative of the mechanical angular velocity. According to the equation, from equations (5), (6), (7) and (8), it can be seen that:

[0092]

[0093] Among them, is x the first derivative of 2, is the second derivative of the mechanical angular velocity;

[0094] Letu = i q 、 If so, obtain the state - space equation of the permanent - magnet synchronous motor, that is, equations (9) and (10) become:

[0095] (11)

[0096] Among them, D is the coefficient of the control input, u is the control input of the permanent - magnet synchronous motor and is the output of the sliding - mode controller.

[0097] Design the sliding - mode controller for the speed loop of the permanent - magnet synchronous motor, including designing a new variable - speed exponential reaching law and a sliding - mode surface function, and deriving the sliding - mode control law based on this reaching law, including: designing a new variable - speed exponential reaching law; designing a suitable sliding - mode surface function; combining the mathematical model of the permanent - magnet synchronous motor in the d - q synchronous rotating coordinate system to derive the sliding - mode control law based on the new variable - speed exponential reaching law. Specifically:

[0098] The new variable - speed exponential reaching law is:

[0099] (12)

[0100] Among them, is the first - order derivative of the sliding - mode surface, ε is the coefficient of the constant - speed reaching term, F ( x, t ) is the additional function of the variable - speed reaching term, x is the state variable of the permanent - magnet synchronous motor system, tanh(▪) is the additional function of the variable - exponential reaching term, s is the sliding - mode surface function, k is the coefficient of the exponential reaching term, G ( s ) is the additional function of the variable - exponential reaching term, α is a constant (between 0 and 1);

[0101] The sliding - mode surface function is:

[0102] (13)

[0103] Among them, C is a constant greater than zero;

[0104] Combining the mathematical model of the permanent - magnet synchronous motor in the d - q synchronous rotating coordinate system, the output of the sliding - mode controller can be obtained, that is, the sliding - mode control law of the permanent - magnet synchronous motor is obtained:

[0105] (14)

[0106] Among them, iq_NewEAL is the output of the sliding mode controller.

[0107] Conduct a stability analysis of the sliding mode controller to prove the stability of the sliding mode controller under the new variable speed exponential reaching law sliding mode control, including: setting the controlled system, selecting the target sliding mode surface function, and obtaining the sliding mode control law by combining the new variable speed exponential reaching law; constructing a Lyapunov function and proving the stability of the system according to the Lyapunov stability theorem. Specifically:

[0108] The set controlled system is:

[0109] (15)

[0110] Among them, is the second derivative of the position signal, f ( x, t ) is a function of the position command, h is a constant (greater than 0), u ( t ) represents the control input, d ( t ) represents the external disturbance;

[0111] The target sliding mode surface function is:

[0112] (16)

[0113] Among them, c is a constant, which must satisfy the Hurwitz condition, c > 0, e ( t ) is the tracking error, is the first derivative of the tracking error;

[0114] The tracking error and its derivative values are:

[0115] (17)

[0116] Among them, x 1 = x , x d is the ideal position signal, is the first derivative of the ideal position signal;

[0117] Taking the derivative of equation (17) gives:

[0118] (18)

[0119] Among them, is the first derivative of the target sliding mode surface, is the second derivative of the tracking error, is the first derivative of the position signal, is the second derivative of the ideal position signal, is the second derivative of the signal position;

[0120] Combined with the new variable-speed exponential reaching law, the sliding mode control law is obtained:

[0121] (19)

[0122] where, u ( t ) is the control input;

[0123] Then, a Lyapunov function is constructed, and the stability of the system is proved according to the Lyapunov stability theorem.

[0124] Among them, the Lyapunov function constructed according to the sliding mode surface function V is as follows:

[0125] (20)

[0126] According to the Lyapunov function and the mathematical model of the permanent magnet synchronous motor in the d-q synchronous rotating coordinate system, that is, combining Equation (9) and Equation (20), it can be deduced that:

[0127] (21)

[0128] where, is the derivative value of the Lyapunov function;

[0129] It can be seen from the Lyapunov stability theorem that the designed sliding mode controller is gradually stable.

[0130] As Figure 2 shown, the working principle of the PMSM controller is explained. The outer loop is the speed loop, and the detected rotational speed ω is used as the feedback; the inner loop is the current loop, and the stator three-phase currents i a , i b and i c are sampled, and then the stator currents i d , i q in the d-q synchronous reference frame are obtained through Clark transformation and Park transformation and used as the feedback. The given rotational speed and the measured rotational speed ω m are subtracted, and then the given value of the q-axis stator current is obtained through the sliding mode controller , and the d-axis current reference value is 0. After the difference between the reference values and the measured values of the two current components passes through a PI controller, the stator voltage in the d-q synchronous reference frame is obtained u d and u q . After the two pass through the PARK inverse transformation, α - β the stator voltage in the u α and u β coordinates is obtained. The input to the SVPWM gives a three-phase duty cycle signal to control the on and off of the inverter switching tubes, thereby realizing the control of the PMSM.

[0131] As Figures 3 - 8 shown, the effects of the motor control method of the present invention and the prior art are compared. Among them, Ref is the given reference speed, PI is the traditional proportional-integral control method, TEAL is the sliding mode control method using the traditional exponential reaching law, and its traditional exponential reaching law is:

[0132] (22)

[0133] where ε sgn ( s ) is the constant speed reaching term, ks represents the exponential reaching term;

[0134] NewEAL is the sliding mode control method using the novel variable-speed exponential reaching law proposed by the present invention, TMSM is the traditional sliding mode surface, and its sliding mode surface function is Equation (13). It can be seen that the speed characteristic and the robustness of the system of the present invention are the best.

[0135] The embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored, and the computer program is executed to run the sliding mode control method of the permanent magnet synchronous motor based on the novel variable-speed exponential reaching law. The computer program can run computer instructions, and the computer instructions include computer program code, and the computer program code can be in the form of source code, object code, executable file or some intermediate form, etc.

[0136] The computer-readable storage medium can include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disc, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electrical carrier signal, telecommunication signal, and software distribution medium, etc.

[0137] 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 storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0138] The present invention is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. 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 generate means for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0139] 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 generate 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.

[0140] 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 executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0141] 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: still can modify the specific implementation manners of the present invention or make equivalent replacements, and any modification or equivalent replacement without departing from the spirit and scope of the present invention should be covered by the protection scope of the claims of the present invention.

Claims

1. A sliding mode control method for a permanent magnet synchronous motor based on a novel variable speed exponential reaching law, characterized in that, Specifically, it includes the following steps: S1. Establish the state - space mathematical model of the permanent - magnet synchronous motor based on the d - q synchronous rotating coordinate system; S2. Establish the sliding - mode control law of the permanent - magnet synchronous motor according to the state - space mathematical model of the permanent - magnet synchronous motor; Establishing the sliding - mode control law of the permanent - magnet synchronous motor according to the state - space mathematical model of the permanent - magnet synchronous motor includes: S2 - 1. Obtain the new variable - speed exponential reaching law and the sliding - mode surface function of the sliding - mode controller of the permanent - magnet synchronous motor speed loop; S2 - 2. According to the state - space mathematical model of the permanent - magnet synchronous motor, use the new variable - speed exponential reaching law and the sliding - mode surface function of the sliding - mode controller of the permanent - magnet synchronous motor speed loop to obtain the sliding - mode control law of the permanent - magnet synchronous motor; The calculation formula of the new variable - speed exponential reaching law of the sliding - mode controller of the permanent - magnet synchronous motor speed loop is as follows: Among them, is the first derivative of the sliding mode surface, ε is the coefficient of the constant velocity approaching term, F ( x,t ) is the additional function of the variable velocity approaching term, x is the state variable of the permanent magnet synchronous motor system, t is the time, and tanh(▪) is the additional function of the variable exponent approaching term, s is the sliding mode surface function, k is the exponent approaching term coefficient, G ( s ) is the additional function of the variable exponent approaching term, α is a constant; S3. Use the sliding - mode control law of the permanent - magnet synchronous motor to obtain the sliding - mode control result of the permanent - magnet synchronous motor based on the Lyapunov function.

2. The sliding mode control method for a permanent magnet synchronous motor based on a novel variable speed exponential reaching law according to claim 1, wherein Establishing the state - space mathematical model of the permanent - magnet synchronous motor based on the d - q synchronous rotating coordinate system includes: S1 - 1. Establish the d - axis voltage, q - axis voltage and torque equations of the stator of the permanent - magnet synchronous motor during synchronous rotation based on the d - q synchronous rotating coordinate system; S1 - 2. According to the d - axis voltage, q - axis voltage and torque equations of the stator of the permanent - magnet synchronous motor during synchronous rotation, obtain the state - space mathematical model of the permanent - magnet synchronous motor.

3. The sliding mode control method for a permanent magnet synchronous motor based on a novel variable speed exponential reaching law according to claim 2, wherein The calculation formulas of the d - axis voltage, q - axis voltage and torque equations of the stator of the permanent - magnet synchronous motor during synchronous rotation are as follows: Among them, i d is the stator current along the d-axis, t is time, L d is the inductance on the d-axis, u d is the stator voltage on the d-axis, R s is the stator resistance, ω e is the electrical angular velocity, L q is the inductance on the q-axis, i q is the stator current along the q-axis, u q is the stator voltage on the q-axis, Ψ f is the permanent magnet flux linkage, ω m is the mechanical angular velocity, J is the moment of inertia of the load, T e is the electromagnetic torque, B a is the viscous coefficient of the load, T L is the load torque, p is the number of pole pairs of the motor.

4. The permanent magnet synchronous motor sliding mode control method based on a novel variable speed exponential reaching law according to claim 2, characterized in that Obtaining the state - space mathematical model of the permanent - magnet synchronous motor according to the d - axis voltage, q - axis voltage and torque equations of the stator of the permanent - magnet synchronous motor during synchronous rotation includes: S1 - 2 - 1. Perform rotor - flux - oriented control according to the d - axis voltage, q - axis voltage and torque equations of the stator of the permanent - magnet synchronous motor during synchronous rotation to obtain rotor - flux - oriented control information; S1 - 2 - 2. Determine the state variables of the permanent - magnet synchronous motor; S1 - 2 - 3. According to the state variables of the permanent - magnet synchronous motor and the rotor - flux - oriented control information, obtain the state - space equation of the permanent - magnet synchronous motor as the state - space mathematical model of the permanent - magnet synchronous motor.

5. The sliding mode control method for a permanent magnet synchronous motor based on a novel variable speed exponential reaching law according to claim 4, characterized in that The calculation formula of the state - space equation of the permanent - magnet synchronous motor is as follows: Among them, and are respectively x 1 x and the first derivative function of 2, , , x 1 is the rotational speed error of the permanent magnet synchronous motor, x 2 is x the first derivative function of 1, ω ref is the reference rotational speed of the permanent magnet synchronous motor, ω m is the mechanical angular velocity, is the first derivative of the mechanical angular velocity, D is the coefficient of the control input, u is the control input of the permanent magnet synchronous motor and is the output of the sliding mode controller.

6. The permanent magnet synchronous motor sliding mode control method based on a novel variable speed exponential reaching law according to claim 1, characterized in that The calculation formula of the sliding - mode surface function of the sliding - mode controller of the permanent - magnet synchronous motor speed loop is as follows: Among them, s is the sliding mode surface function, C is a constant greater than zero, x 1 is the speed error of the permanent magnet synchronous motor, x 2 is x the first derivative function of 1.

7. The sliding mode control method for a permanent magnet synchronous motor based on a novel variable speed exponential reaching law according to claim 1, characterized in that The calculation formula of the sliding - mode control law of the permanent - magnet synchronous motor is as follows: Among them, i q_NewEAL is the output of the sliding mode controller, D is the coefficient of the control input, t is the time, C is a constant greater than zero, x 1 is the speed error of the permanent magnet synchronous motor, ε is the coefficient of the constant speed reaching term, F ( x,t ) is the additional function of the variable speed reaching term, x is the state variable of the permanent magnet synchronous motor system, tanh(▪) is the additional function of the variable exponential reaching term, s is the sliding mode surface function, k is the coefficient of the exponential reaching term, G ( s ) is the additional function of the variable exponential reaching term.

8. The permanent magnet synchronous motor sliding mode control method based on a novel variable speed exponential reaching law according to claim 6, characterized in that Using the sliding - mode control law of the permanent - magnet synchronous motor to obtain the sliding - mode control result of the permanent - magnet synchronous motor based on the Lyapunov function includes: S3 - 1. Construct the Lyapunov function according to the sliding - mode surface function of the sliding - mode controller of the permanent - magnet synchronous motor speed loop; S3 - 2. Based on the Lyapunov function, obtain the derivative value of the Lyapunov function as the sliding - mode control result of the permanent - magnet synchronous motor according to the state - space mathematical model of the permanent - magnet synchronous motor.

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