A synchronous reluctance motor speed control method and system

Abstract

The present invention relates to the field of motor control, and specifically discloses a synchronous reluctance motor speed control method and system, including: constructing a mathematical model of a synchronous reluctance motor in a d-q rotating coordinate system; obtaining the operating state information of the synchronous reluctance motor based on the model; determining a modified convergence law and a global integral sliding surface; and constructing a speed controller to control the speed of the synchronous reluctance motor based on the operating state information of the synchronous reluctance motor, the modified convergence law and the global integral sliding surface. The present invention enables the system of the synchronous reluctance motor to converge quickly based on the improved modified convergence law, and reaches the global integral sliding surface at a preset speed, that is, reaches a stable state, reduces system jitter and improves the dynamic performance of the system, and because the present embodiment provides a globally defined modified convergence law and a global integral sliding surface, there is no singularity problem, which effectively improves the anti-interference and stability of the synchronous reluctance motor.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to a synchronous reluctance motor speed control method and a synchronous reluctance motor speed control system. Background Art

[0002] The emergence of synchronous reluctance motors is to solve various problems existing in traditional motors. Compared with induction motors, permanent magnet synchronous motors and switched reluctance motors, synchronous reluctance motors have a series of advantages. First, the rotor of the synchronous reluctance motor does not require permanent magnets, so the manufacturing cost is low, and there is no problem of high-temperature demagnetization. Secondly, compared with induction motors, synchronous reluctance motors have a smaller volume and higher power density. Thirdly, compared with switched reluctance motors, synchronous reluctance motors have a more compact structure, smaller torque pulsation and lower operating noise. Therefore, in recent years, synchronous reluctance motors have been increasingly widely used in compressors, water pumps and other fields.

[0003] However, in actual industrial applications, synchronous reluctance motor systems are often affected by time-varying disturbances, which mainly include unmodeled dynamics, uncertain model parameters, and external load disturbances. When the synchronous reluctance motor system is affected by these disturbances, traditional linear control strategies such as PID control are difficult to obtain satisfactory control performance. Therefore, it is very important to design a synchronous reluctance motor speed control method that can take into account both dynamic response speed and steady-state control accuracy.

[0004] Since sliding mode variable structure control exhibits the characteristics of fast response time, strong stability and excellent robustness in the field of synchronous reluctance motors, and considering the shortcomings of PID control, sliding mode variable structure is often applied to synchronous reluctance motor control systems in the prior art.

[0005] However, despite the above advantages of the sliding mode variable structure, its design process requires the selection of appropriate sliding surface and reaching law. The synchronous reluctance motor system is often affected by time-varying interference, and there will be singular point problems in the system dynamic equations, that is, when certain state variables or parameters take specific values, the behavior of the system becomes abnormal or discontinuous. This situation may lead to unstable system response or poor control effect. First, when the system is near a singular point, its dynamic characteristics will become very sensitive, which may make the controller design more complicated and weaker in resistance to external disturbances; secondly, singular points usually cause discontinuities or jumps in the system response, which will reduce the performance of the system and make it difficult to meet the requirements of practical applications; in addition, near the singular point, the robustness of the system usually becomes poor, that is, the system's tolerance for parameter changes or modeling errors is reduced. When the system dynamic characteristics are unstable, it becomes a difficult problem to select appropriate sliding surface and reaching law. Improper selection may lead to a decrease in the control performance of the sliding mode variable structure.

[0006] Therefore, how to select an appropriate sliding surface and reaching law to control the speed of the synchronous reluctance motor while improving the anti-interference and stability of the synchronous reluctance motor system has become a technical problem that needs to be urgently solved by technical personnel in this field. Summary of the invention

[0007] The present invention provides a synchronous reluctance motor speed control method and a synchronous reluctance motor speed control system, which solve the problems existing in the related art, such as difficulty in selecting an appropriate sliding surface and reaching law, and low anti-interference and stability of the synchronous reluctance motor system when the synchronous reluctance motor is controlled in speed.

[0008] As a first aspect of the present invention, a synchronous reluctance motor speed control method is provided, comprising:

[0009] Construct the mathematical model of synchronous reluctance motor in dq rotating coordinate system;

[0010] Acquiring the operating status information of the synchronous reluctance motor based on the mathematical model of the synchronous reluctance motor;

[0011] Determine a modified reaching law and determine a global integral sliding surface, wherein the modified reaching law is used to enable the mathematical model of the synchronous reluctance motor to reach the global integral sliding surface at a preset speed;

[0012] A speed controller is constructed based on the operating state information of the synchronous reluctance motor, the modified reaching law and the global integral sliding surface. The speed controller is used to perform speed tracking control on the synchronous reluctance motor.

[0013] Further, determining the modified reaching law includes: obtaining a first modified reaching law according to the exponential reaching law and the power reaching law;

[0014] The expression of the first modified reaching law is:

[0015]

[0016] Among them, s 1 represents the first global integral sliding surface, α 1 and β 1 All represent constants, a 1 Represents a constant, 0<a 1 <1, sign represents the sign function.

[0017] Further, determining the global integral sliding mode surface includes: determining a first global integral sliding mode surface according to an adaptive law;

[0018] The expression of the first global integral sliding surface is:

[0019] s 1 =K P1 e1 +K I1 ∫e 1 dt 1 +K(t 1 ),

[0020] Among them, K P1 and K I1 All represent constants, e 1 represents the first speed error of the synchronous reluctance motor, K(t 1 ) represents the adaptive law, t 1 represents time, λ 1 and b 1 Both represent constants, λ 1 >0,b 1 >0.

[0021] Furthermore, a speed controller is constructed based on the synchronous reluctance motor operating state information, the modified reaching law and the global integral sliding surface, including:

[0022] Obtaining a first speed error of the synchronous reluctance motor according to a difference between a first reference speed and a first rotor mechanical angular speed of the synchronous reluctance motor;

[0023] A first speed controller is obtained according to a first speed error of the synchronous reluctance motor and a first global integrated sliding mode surface.

[0024] Furthermore, the expression of the first speed controller is:

[0025]

[0026] in, represents the first q-axis output current of the synchronous reluctance motor, J represents the rotor inertia of the synchronous reluctance motor, K P1 represents a constant, ω ref1 represents the first reference speed, represents the derivative of the first reference velocity, K T1 represents the first torque constant of the synchronous reluctance motor, K T1 =3p(L d1 -L q1 )i d1 i q1 , p represents the number of pole pairs of the synchronous reluctance motor, L d1 represents the first d-axis self-inductance of the synchronous reluctance motor, L q1 represents the first q-axis self-inductance of the synchronous reluctance motor, i d1 represents the first d-axis stator current of the synchronous reluctance motor, i q1 represents the first q-axis stator current of the synchronous reluctance motor, F represents the damping coefficient of the synchronous reluctance motor, ω 1represents the first rotor mechanical angular velocity of the synchronous reluctance motor, and ω 1 =pω e1 ,ω e1 represents the first rotor electrical angular velocity of the synchronous reluctance motor, T L1 represents the first load torque of the synchronous reluctance motor, K I1 represents a constant, e 1 represents the first speed error of the synchronous reluctance motor, b 1 represents a constant, b 1 >0, K(t 1 ) represents the adaptive law, λ 1 represents a constant, λ 1 >0,t 1 represents time, α 1 and β 1 represents a constant, a 1 Represents a constant, 0<a 1 <1, sign represents the sign function, s 1 represents the first global integrated sliding surface.

[0027] Further, determining the modified reaching law includes: obtaining a second modified reaching law according to a homogeneous function, a piecewise function, an integral function, and an exponential function;

[0028] The expression of the second modified reaching law is:

[0029]

[0030] in, represents the second modified reaching law, s 2 represents the second global integral sliding surface, k 1 , k 2 and k 3 Both represent constants, β 2 represents a constant, and 0<β 2 <1, sign represents the sign function, t 2 represents time, α 2 represents a constant, and α 2 >0, ε represents a constant, 0<ε<1, γ represents a constant, γ>0.

[0031] Furthermore, the global integral sliding surface includes a second global integral sliding surface, and the expression of the second global integral sliding surface is:

[0032] s 2 =e 2 +c∫e 2 ,

[0033] Where c represents the gain, e 2Represents the second speed error of the synchronous reluctance motor.

[0034] Furthermore, a speed controller is constructed based on the synchronous reluctance motor operating state information, the modified reaching law and the global integral sliding surface, including:

[0035] Obtaining a second speed error of the synchronous reluctance motor according to a difference between a second rotor mechanical angular speed of the synchronous reluctance motor and a second reference speed;

[0036] A second speed controller is obtained according to a second speed error of the synchronous reluctance motor and a second global integral sliding mode surface;

[0037] The expression of the second speed controller is:

[0038]

[0039] in, represents the second q-axis output current of the synchronous reluctance motor, J represents the rotor inertia of the synchronous reluctance motor, K T2 represents the second torque constant of the synchronous reluctance motor, K T2 =3p(L d2 -L q2 )i d2 i q2 , p represents the number of pole pairs of the synchronous reluctance motor, L d2 represents the second d-axis self-inductance of the synchronous reluctance motor, L q2 represents the second q-axis self-inductance of the synchronous reluctance motor, i d2 represents the second d-axis stator current of the synchronous reluctance motor, i q2 represents the second q-axis stator current of the synchronous reluctance motor, ω ref2 represents the second reference speed, F represents the damping coefficient of the synchronous reluctance motor, ω 2 represents the mechanical angular velocity of the second rotor of the synchronous reluctance motor, and ω 2 =pω e2 ,ω e2 represents the electrical angular velocity of the second rotor of the synchronous reluctance motor, T L2 represents the second load torque of the synchronous reluctance motor, c represents the gain, e represents the 2 represents the second speed error of the synchronous reluctance motor, k 1 , k 2 and k 3 All represent constants, s 2 represents the second global integral sliding surface, β 2 represents a constant, sign represents a sign function, t 2 represents time, α 2 represents a constant, and α 2 >0.

[0040] Furthermore, the mathematical model of the synchronous reluctance motor is expressed as:

[0041]

[0042] Among them, u d represents the d-axis stator voltage of the synchronous reluctance motor, u q represents the q-axis stator voltage of the synchronous reluctance motor, i d represents the d-axis stator current of the synchronous reluctance motor, i q represents the q-axis stator current of the synchronous reluctance motor, R s represents the armature resistance of the synchronous reluctance motor, represents the derivative of the d-axis flux component of the synchronous reluctance motor, represents the derivative of the q-axis flux component of the synchronous reluctance motor, ω represents the rotor mechanical angular velocity of the synchronous reluctance motor, and ω=pω e , p represents the number of pole pairs of the synchronous reluctance motor, ω e represents the rotor electrical angular velocity of the synchronous reluctance motor, L d represents the d-axis self-inductance of the synchronous reluctance motor, L q represents the q-axis self-inductance of the synchronous reluctance motor, T e is the electromagnetic torque of the synchronous reluctance motor, T L is the load torque of the synchronous reluctance motor, K T represents the torque constant of the synchronous reluctance motor, K T =3p(L d -L q )i d i q , F represents the damping coefficient of the synchronous reluctance motor, and J represents the rotor moment of inertia of the synchronous reluctance motor.

[0043] As another aspect of the present invention, there is provided a synchronous reluctance motor speed control system, comprising:

[0044] A model building module is used to build a mathematical model of a synchronous reluctance motor in a dq rotating coordinate system;

[0045] An information acquisition module, used for acquiring the operating status information of the synchronous reluctance motor according to a mathematical model of the synchronous reluctance motor;

[0046] A sliding mode design module is used to determine a modified reaching law and a global integral sliding mode surface, wherein the modified reaching law is used to enable the mathematical model of the synchronous reluctance motor to reach the global integral sliding mode surface at a preset speed;

[0047] The speed control module is used to obtain the operating status information of the synchronous reluctance motor from the information acquisition module, obtain the modified reaching law and the global integral sliding surface from the sliding mode design module, and build a speed controller based on the operating status information of the synchronous reluctance motor, the modified reaching law and the global integral sliding surface. The speed controller is used to perform speed tracking control on the synchronous reluctance motor.

[0048] The synchronous reluctance motor speed control method and system provided by the present invention enable the synchronous reluctance motor system to converge quickly based on the improved modified convergence law and reach the global integral sliding surface at a preset speed, so that the synchronous reluctance motor system can quickly reach a stable state at a preset speed, thereby reducing the system's jitter and improving the system's dynamic performance. Moreover, since this embodiment provides a globally defined modified convergence law and a global integral sliding surface, it does not involve singularity problems, thereby effectively improving the anti-interference and stability of the synchronous reluctance motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention, but do not constitute a limitation of the present invention.

[0050] Figure 1 A flow chart of a synchronous reluctance motor speed control method provided by the present invention;

[0051] Figure 2 A flow chart for constructing a first speed controller provided by the present invention;

[0052] Figure 3 A structural block diagram of a first speed controller provided by the present invention;

[0053] Figure 4 A flow chart for constructing a second speed controller provided by the present invention;

[0054] Figure 5 A structural block diagram of a second speed controller provided by the present invention;

[0055] Figure 6 A structural block diagram of a synchronous reluctance motor speed control system provided by the present invention;

[0056] Figure 7 A working principle diagram of the synchronous reluctance motor speed control system provided by the present invention;

[0057] Figure 8 Another working principle diagram of the synchronous reluctance motor speed control system provided by the present invention. DETAILED DESCRIPTION

[0058] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0059] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

[0060] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so as to describe the embodiments of the present invention described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0061] In an embodiment of the present invention, a method for controlling the speed of a synchronous reluctance motor is provided. Figure 1 is a flow chart of a synchronous reluctance motor speed control method according to an embodiment of the present invention. Figure 1 As shown, including:

[0062] S1. Construct a mathematical model of synchronous reluctance motor in dq rotating coordinate system;

[0063] The dq rotating coordinate system is the rotor rotating coordinate system. The dq rotating coordinate system can compensate for the time variation in the stationary coordinate system by converting the mathematical model of the synchronous reluctance motor into a two-phase model of the rotating reference coordinate system fixed on the rotor of the synchronous reluctance motor. The voltage equation u in the dq rotating coordinate system is d and u q The speed and torque of the synchronous reluctance motor can be effectively controlled, so the embodiment of the present invention chooses to construct a mathematical model of the synchronous reluctance motor in a dq rotating coordinate system;

[0064] S2. Acquiring the operating status information of the synchronous reluctance motor based on the mathematical model of the synchronous reluctance motor;

[0065] Specifically, the synchronous reluctance motor operating state information described in this step includes the rotor mechanical angular velocity of the synchronous reluctance motor, the rotor electrical angular velocity of the synchronous reluctance motor, the rotor moment of inertia of the synchronous reluctance motor, the torque constant of the synchronous reluctance motor, the d-axis self-inductance of the synchronous reluctance motor, the q-axis self-inductance of the synchronous reluctance motor, the d-axis stator current of the synchronous reluctance motor, the q-axis stator current of the synchronous reluctance motor, the damping coefficient of the synchronous reluctance motor, the load torque of the synchronous reluctance motor, etc.;

[0066] S3, determining a modified reaching law and determining a global integral sliding surface, wherein the modified reaching law is used to enable the mathematical model of the synchronous reluctance motor to reach the global integral sliding surface at a preset speed;

[0067] The modified reaching law provided in the embodiment of the present invention can make the system of the synchronous reluctance motor converge quickly and reach the global integral sliding mode surface at a preset speed, and the modified reaching law provided in this embodiment and the global integral sliding mode surface have a global definition;

[0068] S4. A speed controller is constructed based on the operating state information of the synchronous reluctance motor, the modified reaching law and the global integral sliding surface. The speed controller is used to perform speed tracking control on the synchronous reluctance motor.

[0069] The embodiment of the present invention enables the system of the synchronous reluctance motor to converge quickly based on the improved modified convergence law and reach the global integral sliding surface at a preset speed, that is, the system of the synchronous reluctance motor can quickly reach a stable state at a preset speed, thereby reducing the jitter of the system and improving the dynamic performance of the system. Moreover, since the present embodiment provides a modified convergence law and a global integral sliding surface with a global definition, it does not involve the singularity problem. Since there is no singularity problem, the problem of discontinuity or jump in the response of the system when the synchronous reluctance motor is near the singularity point is avoided, and the resistance of the system will not be affected by the singularity problem, thereby effectively improving the anti-interference and stability of the synchronous reluctance motor.

[0070] Specifically, determining the modified reaching law includes: obtaining a first modified reaching law according to the exponential reaching law and the power reaching law;

[0071] The expression of the first modified reaching law is:

[0072]

[0073] Among them, s 1 represents the first global integral sliding surface, α 1 and β 1 All represent constants, a 1 Represents a constant, 0<a 1 <1, sign represents the sign function.

[0074] The first modified reaching law provided in this embodiment introduces the exponential reaching law The exponential term βs in can enhance the approximation of the synchronous reluctance motor system to the global integrated sliding mode surface with the value s, making the synchronous reluctance motor system have a faster convergence speed.

[0075] In addition, the first modified reaching law also introduces the power reaching law The power term |s| a , adjust the power term when the synchronous reluctance motor system is far away from the global integral sliding surface a 1 , which can ensure that the system state of the synchronous reluctance motor approaches the sliding mode at a higher speed when it is far away from the global integral sliding mode surface; and that the system state of the synchronous reluctance motor approaches the sliding mode at a lower speed when it approaches the global integral sliding mode surface, thereby reducing chattering.

[0076] Further, determining the global integral sliding mode surface includes: determining a first global integral sliding mode surface according to an adaptive law;

[0077] The expression of the first global integral sliding surface is:

[0078] s 1 =K P1 e 1 +K I1 ∫e 1 dt 1 +K(t 1 ),

[0079] Among them, K P1 and K I1 All represent constants, e 1 represents the first speed error of the synchronous reluctance motor, K(t 1 ) represents the adaptive law, t 1 represents time, λ 1 and b 1 Both represent constants, λ 1 >0,b 1 >0.

[0080] Introducing the adaptive law K(t 1 ) can be adaptively updated according to the actual operating state of the synchronous reluctance motor, thereby improving the following ability of the synchronous reluctance motor system, thereby improving the robustness of the synchronous reluctance motor system, and can further improve the control performance of the speed controller on the synchronous reluctance motor system.

[0081] Further, Figure 2 The flowchart of constructing the first speed controller provided by the present invention is as follows: Figure 2As shown in FIG. 1 , a speed controller is constructed based on the operating state information of the synchronous reluctance motor, the modified reaching law and the global integral sliding surface, including:

[0082] S411. Obtain a first speed error of the synchronous reluctance motor according to a difference between a first reference speed and a first rotor mechanical angular velocity of the synchronous reluctance motor; wherein the value of the first reference speed may be set according to actual conditions.

[0083] S412, obtaining a first speed controller according to the first speed error of the synchronous reluctance motor and the first global integral sliding mode surface. This step may further include:

[0084] Derivative the first speed error of the synchronous reluctance motor to obtain a first-order derivative of the first speed error;

[0085] Deriving the first global integral sliding surface to obtain a first-order derivative of the first global integral sliding surface;

[0086] The first speed error and the first-order derivative of the synchronous reluctance motor are substituted into the first-order derivative of the first global integral sliding surface, and the first speed controller is obtained through derivation.

[0087] The first global integral sliding surface is applied to the first speed controller through the first modified reaching law. The first global integral sliding surface eliminates the arrival stage, responds quickly, and makes the sliding mode control of the first speed controller sensitive to the global response, so that the system of the synchronous reluctance motor has better following ability, thereby improving the robustness of the synchronous reluctance motor system and achieving high-precision control.

[0088] Specifically, Figure 3 The structural block diagram of the first speed controller provided by the present invention is as follows: Figure 3 As shown, the expression of the first speed controller is:

[0089]

[0090] in, represents the first q-axis output current of the synchronous reluctance motor, J represents the rotor inertia of the synchronous reluctance motor, K P1 represents a constant, ω ref1 represents the first reference speed, represents the derivative of the first reference velocity, K T1 represents the first torque constant of the synchronous reluctance motor, K T1 =3p(L d1 -L q1 )i d1 i q1 , p represents the number of pole pairs of the synchronous reluctance motor, L d1 represents the first d-axis self-inductance of the synchronous reluctance motor, Lq1 represents the first q-axis self-inductance of the synchronous reluctance motor, i d1 represents the first d-axis stator current of the synchronous reluctance motor, i q1 represents the first q-axis stator current of the synchronous reluctance motor, F represents the damping coefficient of the synchronous reluctance motor, ω 1 represents the first rotor mechanical angular velocity of the synchronous reluctance motor, and ω 1 =pω e1 ,ω e1 represents the first rotor electrical angular velocity of the synchronous reluctance motor, T L1 represents the first load torque of the synchronous reluctance motor, K I1 represents a constant, e 1 represents the first speed error of the synchronous reluctance motor, b 1 represents a constant, b 1 >0, K(t 1 ) represents the adaptive law, λ 1 represents a constant, λ 1 >0,t 1 represents time, α 1 and β 1 represents a constant, a 1 Represents a constant, 0<a 1 <1, sign represents the sign function, s 1 represents the first global integrated sliding surface.

[0091] The embodiment of the present invention defines the first speed error of the synchronous reluctance motor as:

[0092] e 1 =ω ref1 -ω 1 ,

[0093] For the first speed error e 1 The first-order derivative of the first velocity error is obtained by taking the derivative:

[0094]

[0095] For the first global integral sliding surface s 1 Derivative, obtain the first-order derivative of the first global integral sliding surface:

[0096]

[0097] Substituting the first velocity error and the first-order derivative of the first velocity error into the first-order derivative of the first global integral sliding surface, we can obtain:

[0098]

[0099] Thus, the expression of the first speed controller is derived:

[0100]

[0101] Based on the above content, the stability of the synchronous reluctance motor speed control method provided by the embodiment of the present invention is analyzed, and the Lyapunov function is defined as:

[0102]

[0103] V 1 Taking the derivative, we get:

[0104]

[0105] Due to α 1 and β 1 All represent constants, and are positive numbers in the embodiments of the present invention. The verification results can prove that the present embodiment satisfies the Lyapunov stability theorem, that is, the speed error of the synchronous reluctance motor system can be converged to zero within a limited time frame through the first modified reaching law and the first global integral sliding surface provided by the present invention, which also proves that the synchronous reluctance motor speed control method provided by the embodiment of the present invention enables the synchronous reluctance motor system to have good stability and anti-interference performance.

[0106] In another embodiment provided by the present invention, determining the modified convergence law includes: obtaining a second modified convergence law according to a homogeneous function, a piecewise function, an integral function and an exponential function;

[0107] The expression of the second modified reaching law is:

[0108]

[0109] in, represents the second modified reaching law, s 2 represents the second global integral sliding surface, k 1 , k 2 and k 3 Both represent constants and are positive numbers, β 2 represents a constant, and 0<β 2 <1, sign represents the sign function, t 2 represents time, α 2 represents a constant, and α 2 >0, ε represents a constant, 0<ε<1, γ represents a constant, γ>0.

[0110] This embodiment is achieved by transforming the homogeneous function of the absolute value The introduction of the second modified reaching law can ensure the continuity of the control input and thus reduce chattering.

[0111] This embodiment also introduces a piecewise function f(s) into the second modified reaching law. 2 ), when the system state of the synchronous reluctance motor is close to the target value 0, through f(s 2 )Regulate the control input Further stabilize the system and reduce system speed.

[0112] Specifically, when |s 2 |≥ε, f(s 2 ) is the symbolic function, f(s 2 )=sign(s 2 ), control input Only by s 2 This means that the control input Consistent with the direction of the current system state, control input Can offset 2 The deviation from zero can quickly adjust the system state toward the target value, thereby achieving a rapid response of the synchronous reluctance motor system to external requirements or interference. This rapid response capability can ensure that the system quickly reaches a stable state.

[0113] When|s 2 |<ε, Control Input Still affected by 2 The influence of ε and γ make the three meet a certain proportional relationship, so that s 2 When it approaches zero, the control input This enables smooth transitions, reducing system oscillations and providing more precise control, which allows the system to operate more stably when approaching the target value.

[0114] In summary, as the system state approaches the target value, the piecewise function f(s 2 ) can adjust the control input Precise changes allow the system speed to be stabilized with minimal deviation.

[0115] In addition, the second modified reaching law of this embodiment also introduces the integral function k 2 ∫sign(s 2 )dt 2 and exponential function The integral function is continuous and can therefore further reduce jitter, while the exponential function is used to provide attenuation control when the state of the synchronous reluctance motor system approaches zero, so as to prevent the system output from deviating from the steady-state value and generating oscillation, thereby ensuring the stability of the synchronous reluctance motor system.

[0116] Furthermore, the global integral sliding surface includes a second global integral sliding surface, and the expression of the second global integral sliding surface is:

[0117] s 2 =e 2 +c∫e 2 ,

[0118] Where c represents the gain, e 2 Represents the second speed error of the synchronous reluctance motor.

[0119] In this embodiment, the gain c is specifically a positive gain, and the second global integral sliding mode surface has a global definition and is globally stable, and does not involve singularity problems.

[0120] Further, Figure 4 The flowchart for constructing the second speed controller provided in this embodiment is as follows: Figure 4 As shown in FIG. 1 , a speed controller is constructed based on the operating state information of the synchronous reluctance motor, the modified reaching law and the global integral sliding surface, including:

[0121] S421, obtaining a second speed error of the synchronous reluctance motor according to a difference between a second rotor mechanical angular velocity of the synchronous reluctance motor and a second reference speed;

[0122] S422, obtaining a second speed controller according to the second speed error of the synchronous reluctance motor and the second global integral sliding mode surface; this step may further include:

[0123] Derivative the second speed error of the synchronous reluctance motor to obtain a first-order derivative of the second speed error;

[0124] Deriving the second global integral sliding surface to obtain a first-order derivative of the second global integral sliding surface;

[0125] The second speed error and the first-order derivative of the second speed error of the synchronous reluctance motor are substituted into the first-order derivative of the second global integral sliding surface, and the second speed controller is obtained through derivation.

[0126] A second global integral sliding surface is applied to the second speed controller through a second modified reaching law. The second global integral sliding surface makes the sliding mode control of the second speed controller sensitive to the global response, thereby making the entire sliding mode control process robust and enabling high-precision control.

[0127] Figure 5 A structural block diagram of a second speed controller provided by an embodiment of the present invention, such as Figure 5 As shown, the expression of the second speed controller is:

[0128]

[0129] in, represents the second q-axis output current of the synchronous reluctance motor, J represents the rotor inertia of the synchronous reluctance motor, K T2 represents the second torque constant of the synchronous reluctance motor, K T2 =3p(L d2 -L q2 )i d2 i q2 , p represents the number of pole pairs of the synchronous reluctance motor, L d2 represents the second d-axis self-inductance of the synchronous reluctance motor, L q2 represents the second q-axis self-inductance of the synchronous reluctance motor, i d2 represents the second d-axis stator current of the synchronous reluctance motor, i q2 represents the second q-axis stator current of the synchronous reluctance motor, ω ref2 represents the second reference speed, F represents the damping coefficient of the synchronous reluctance motor, ω 2 represents the mechanical angular velocity of the second rotor of the synchronous reluctance motor, and ω 2 =pω e2 ,ω e2 represents the electrical angular velocity of the second rotor of the synchronous reluctance motor, T L2 represents the second load torque of the synchronous reluctance motor, c represents the gain, e represents the 2 represents the second speed error of the synchronous reluctance motor, k 1 , k 2 and k 3 All represent constants, s 2 represents the second global integral sliding surface, β 2 represents a constant, sign represents a sign function, t 2 represents time, α 2 represents a constant, and α 2 >0.

[0130] The embodiment of the present invention defines the second speed error of the synchronous reluctance motor as:

[0131] e 2 =ω 2 -ω ref2 ,

[0132] For the second speed error e 2 The first-order derivative of the second velocity error is obtained by taking the derivative:

[0133]

[0134] For the second global integral sliding surface s 2 Derivative, obtain the first-order derivative of the second global integral sliding surface:

[0135]

[0136] Substituting the second velocity error and the first-order derivative of the second velocity error into the first-order derivative of the second global integral sliding surface, we can obtain:

[0137]

[0138] Thus, the expression of the second speed controller is derived:

[0139]

[0140] The stability of the synchronous reluctance motor speed control method provided by the embodiment of the present invention is analyzed, and the Lyapunov function is defined as:

[0141]

[0142] V 2 Taking the derivative, we get:

[0143]

[0144] Since k in the embodiment of the present invention 1 , k 2 and k 3 are greater than 0, α 2 >0,0<β 2 <1, then is a negative value, which indicates that the Lyapunov function decreases with the passage of time. This embodiment satisfies the Lyapunov stability theorem, that is, the speed error of the synchronous reluctance motor system can converge to zero within a limited time frame through the second modified reaching law and the second global integral sliding surface provided by the present invention. This also proves that the synchronous reluctance motor speed control method provided by the embodiment of the present invention enables the synchronous reluctance motor system to have good stability and anti-interference performance.

[0145] Furthermore, the mathematical model of the synchronous reluctance motor provided by the embodiment of the present invention is expressed as follows:

[0146]

[0147] Among them, u d represents the d-axis stator voltage of the synchronous reluctance motor, u q represents the q-axis stator voltage of the synchronous reluctance motor, i d represents the d-axis stator current of the synchronous reluctance motor, i q represents the q-axis stator current of the synchronous reluctance motor, R s represents the armature resistance of the synchronous reluctance motor, represents the derivative of the d-axis flux component of the synchronous reluctance motor, represents the derivative of the q-axis flux component of the synchronous reluctance motor, ω represents the rotor mechanical angular velocity of the synchronous reluctance motor, and ω=pω e , p represents the number of pole pairs, ω e represents the rotor electrical angular velocity of the synchronous reluctance motor, L d represents the d-axis self-inductance of the synchronous reluctance motor, L q represents the q-axis self-inductance of the synchronous reluctance motor, T e is the electromagnetic torque of the synchronous reluctance motor, T L is the load torque of the synchronous reluctance motor, K T represents the torque constant of the synchronous reluctance motor, K T =3p(L d -L q )i d i q , F represents the damping coefficient of the synchronous reluctance motor, and J represents the rotor moment of inertia of the synchronous reluctance motor.

[0148] Another embodiment of the present invention provides a synchronous reluctance motor speed control system 100. Figure 6 is a structural block diagram of the synchronous reluctance motor speed control system provided in this embodiment, such as Figure 6 As shown, including:

[0149] A model building module 110 is used to build a mathematical model of a synchronous reluctance motor in a dq rotating coordinate system;

[0150] An information acquisition module 120 is used to acquire the operating state information of the synchronous reluctance motor according to a mathematical model of the synchronous reluctance motor;

[0151] A sliding mode design module 130, used to determine a modified reaching law and determine a global integral sliding mode surface, wherein the modified reaching law is used to make the mathematical model of the synchronous reluctance motor reach the global integral sliding mode surface at a preset speed;

[0152] The speed control module 140 is used to obtain the operating status information of the synchronous reluctance motor from the information acquisition module 120, obtain the modified reaching law and the global integral sliding surface from the sliding mode design module 130, and construct a speed controller based on the operating status information of the synchronous reluctance motor, the modified reaching law and the global integral sliding surface. The speed controller is used to perform speed tracking control on the synchronous reluctance motor.

[0153] In one case, this embodiment uses vector control to control the speed of the synchronous reluctance motor. Figure 7 The working principle diagram of the synchronous reluctance motor speed control system provided by the present invention is as follows: Figure 7As shown, the model building module 110 builds a mathematical model of the synchronous reluctance motor SynRM, the information acquisition module 120 includes a speed and position detector, the speed and position detector acquires the first rotor mechanical angular velocity of the synchronous reluctance motor, the sliding mode design module 130 determines the first modified reaching law and determines the first global integral sliding mode surface, the speed control module 140 acquires the first modified reaching law and the first global integral sliding mode surface from the sliding mode design module 130, and the speed control module 140 obtains the synchronous reluctance motor operating state information, that is, the first rotor mechanical angular velocity and other information from the speed and position detector. Then, based on the synchronous reluctance motor operating state information, the first modified reaching law and the first global integral sliding mode surface, the first speed controller 1401 is constructed, and the difference between the first reference speed and the first rotor mechanical angular velocity of the synchronous reluctance motor is used as input, and the output is the q-axis stator current of the speed outer loop. D-axis stator current of the speed outer ring The q-axis stator current of the speed outer loop and the d-axis stator current As the input of the q-axis component and the d-axis component of the synchronous reluctance motor respectively, the stator currents of the d-axis and q-axis of the synchronous reluctance motor detected in real time by the speed and position detectors are transformed by Clark and Park to obtain the q-axis stator current i of the synchronous reluctance motor. q1 and the d-axis stator current i of the synchronous reluctance motor d1 , after transformation i q1 and i d1 As feedback value, with i q1 The difference between with i d1 The difference is adjusted by the current inner loop, and then after the inverse Park transformation, the stator voltage V is generated. α1 and V β1 The generated stator voltage passes through the space vector pulse width modulation circuit SVPWM and then passes through the inverter to generate a voltage modulation signal to achieve motor speed control.

[0154] In another case, this embodiment also uses vector control to control the speed of the synchronous reluctance motor. Figure 8 Another working principle diagram of the synchronous reluctance motor speed control system provided by the present invention is as follows: Figure 8As shown, the model building module 110 builds a mathematical model of the synchronous reluctance motor SynRM, the information acquisition module 120 includes a speed and position detector, the speed and position detector acquires the second rotor mechanical angular velocity of the synchronous reluctance motor, the sliding mode design module 130 determines the second modified reaching law and determines the second global integral sliding mode surface, the speed control module 140 acquires the second modified reaching law and the second global integral sliding mode surface from the sliding mode design module 130, and the speed control module 140 obtains the synchronous reluctance motor operating state information, that is, the second rotor mechanical angular velocity and other information from the speed and position detector. Then, based on the synchronous reluctance motor operating state information, the second modified reaching law and the second global integral sliding mode surface, the second speed controller 1402 is constructed, and the difference between the second rotor mechanical angular velocity of the synchronous reluctance motor and the second reference speed is used as input, and the output is the q-axis stator current of the speed outer loop. D-axis stator current of the speed outer ring The q-axis stator current of the speed outer loop and the d-axis stator current As the input of the q-axis component and the d-axis component of the synchronous reluctance motor respectively, the stator currents of the d-axis and q-axis of the synchronous reluctance motor detected in real time by the speed and position detectors are transformed by Clark and Park to obtain the q-axis stator current i of the synchronous reluctance motor. q2 and the d-axis stator current i of the synchronous reluctance motor d2 , after transformation i q2 and i d2 As feedback value, with i q2 The difference between with i d2 The difference is adjusted by the current inner loop, and then after the inverse Park transformation, the stator voltage V is generated. α2 and V β2 The generated stator voltage passes through the space vector pulse width modulation circuit SVPWM and then passes through the inverter to generate a voltage modulation signal to achieve motor speed control.

[0155] The synchronous reluctance motor speed control system provided in the embodiment of the present invention enables the synchronous reluctance motor system to converge quickly based on the improved modified convergence law, and quickly reach the global integral sliding surface at a preset speed, so that the synchronous reluctance motor system can quickly reach a stable state at a preset speed, thereby reducing the jitter of the system and improving the dynamic performance of the system. Moreover, since this embodiment provides a globally defined modified convergence law and a global integral sliding surface, it does not involve singularity problems, thereby effectively improving the anti-interference and stability of the synchronous reluctance motor.

[0156] The specific working principle of the synchronous reluctance motor speed control system provided by the embodiment of the present invention can be referred to the description of the synchronous reluctance motor speed control method above, which will not be repeated here.

[0157] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for controlling the speed of a synchronous reluctance motor, characterized in that: include: Construct the mathematical model of synchronous reluctance motor in dq rotating coordinate system; Acquiring the synchronous reluctance motor operating state information based on the synchronous reluctance motor mathematical model; Determining a modified reaching law and determining a global integral sliding mode surface, wherein the modified reaching law is used to enable the mathematical model of the synchronous reluctance motor to reach the global integral sliding mode surface at a preset speed; A speed controller is constructed based on the operating state information of the synchronous reluctance motor, the modified reaching law and the global integral sliding surface, wherein the speed controller is used to perform speed tracking control on the synchronous reluctance motor; Wherein, the determining of the modified reaching law comprises: obtaining a second modified reaching law according to a homogeneous function, a piecewise function, an integral function and an exponential function; The expression of the second modified reaching law is: in, represents the second modified reaching law, s2 represents the second global integrated sliding surface, k1, k2 and k3 all represent constants, β2 represents a constant, and 0<β2<1, sign represents a sign function, t2 represents time, α2 represents a constant, and α2>0, ε represents a constant, 0<ε<1, γ represents a constant, and γ>0.

2. The method according to claim 1, characterized in that The global integral sliding surface includes a second global integral sliding surface, and the expression of the second global integral sliding surface is: s2=e2+c∫e2, Wherein, c represents the gain, and e2 represents the second speed error of the synchronous reluctance motor.

3. The method according to claim 2, characterized in that The speed controller is constructed based on the synchronous reluctance motor operation state information, the modified reaching law and the global integral sliding mode surface, comprising: Obtaining a second speed error of the synchronous reluctance motor according to a difference between a second rotor mechanical angular speed of the synchronous reluctance motor and a second reference speed; A second speed controller is obtained according to a second speed error of the synchronous reluctance motor and a second global integral sliding mode surface; The expression of the second speed controller is: in, represents the second q-axis output current of the synchronous reluctance motor, J represents the rotor inertia of the synchronous reluctance motor, K T2 represents the second torque constant of the synchronous reluctance motor, K T2 =3p(L d2 -L q2 )i d2 i q2 , p represents the number of pole pairs of the synchronous reluctance motor, L d2 represents the second d-axis self-inductance of the synchronous reluctance motor, L q2 represents the second q-axis self-inductance of the synchronous reluctance motor, i d2 represents the second d-axis stator current of the synchronous reluctance motor, i q2 represents the second q-axis stator current of the synchronous reluctance motor, ω ref2 represents the second reference speed, F represents the damping coefficient of the synchronous reluctance motor, ω2 represents the second rotor mechanical angular velocity of the synchronous reluctance motor, and ω2=pω e2 ,ω e2 represents the electrical angular velocity of the second rotor of the synchronous reluctance motor, T L2 represents the second load torque of the synchronous reluctance motor, c represents the gain, e2 represents the second speed error of the synchronous reluctance motor, k1, k2 and k3 all represent constants, s2 represents the second global integral sliding surface, β2 represents a constant, sign represents a sign function, t2 represents time, α2 represents a constant, and α2>0.

4. The method according to claim 1, characterized in that The mathematical model of the synchronous reluctance motor is expressed as: Among them, u d represents the d-axis stator voltage of the synchronous reluctance motor, u q represents the q-axis stator voltage of the synchronous reluctance motor, i d represents the d-axis stator current of the synchronous reluctance motor, i q represents the q-axis stator current of the synchronous reluctance motor, R s represents the armature resistance of the synchronous reluctance motor, represents the derivative of the d-axis flux component of the synchronous reluctance motor, represents the derivative of the q-axis flux component of the synchronous reluctance motor, ω represents the rotor mechanical angular velocity of the synchronous reluctance motor, and ω=pω e , p represents the number of pole pairs of the synchronous reluctance motor, ω e represents the rotor electrical angular velocity of the synchronous reluctance motor, L d represents the d-axis self-inductance of the synchronous reluctance motor, L q represents the q-axis self-inductance of the synchronous reluctance motor, T e is the electromagnetic torque of the synchronous reluctance motor, T L is the load torque of the synchronous reluctance motor, K T represents the torque constant of the synchronous reluctance motor, K T =3p(L d -L q )i d i q , F represents the damping coefficient of the synchronous reluctance motor, and J represents the rotor moment of inertia of the synchronous reluctance motor.

5. A synchronous reluctance motor speed control system, used to implement the synchronous reluctance motor speed control method according to any one of claims 1 to 4, characterized in that: include: A model building module is used to build a mathematical model of a synchronous reluctance motor in a dq rotating coordinate system; An information acquisition module, used for acquiring the operating state information of the synchronous reluctance motor according to the mathematical model of the synchronous reluctance motor; A sliding mode design module, used to determine a modified reaching law and a global integral sliding mode surface, wherein the modified reaching law is used to make the mathematical model of the synchronous reluctance motor reach the global integral sliding mode surface at a preset speed; A speed control module is used to obtain the operating state information of the synchronous reluctance motor from the information acquisition module, obtain the modified reaching law and the global integral sliding surface from the sliding mode design module, and construct a speed controller based on the operating state information of the synchronous reluctance motor, the modified reaching law and the global integral sliding surface, and the speed controller is used to perform speed tracking control on the synchronous reluctance motor.

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