Rotation speed limited permanent magnet synchronous motor angular displacement servo control method and device

Abstract

The invention discloses a rotating speed limited permanent magnet synchronous motor angular displacement servo control method and device, and relates to the technical field of servo drive, and the method comprises the following steps: S1, designing a transition process which comprises three stages of starting, constant speed operation and braking; determining the time of each stage, and determining the planned amount of motion according to the time of each stage, including an expected angular displacement theta d, an expected angular velocity omega d and an expected angular acceleration ad; and S2, designing a mechanical ring active-disturbance-rejection backstepping controller to accurately track the expected angular displacement theta d and the expected angular velocity omega d. Through the design of the transition process and the design of the controller, the angular displacement and the angular velocity of the motor can accurately track and plan the expected angular displacement and the expected angular velocity; the design of the closed-loop control system not only improves the stability and accuracy of the device in the operation process, but also obviously enhances the overall performance of the alternating current servo system under the condition that the rotating speed is limited.

Description

Technical Field

[0001] The present invention relates to the technical field of servo drive, and in particular to a method and device for controlling the angular displacement servo of a permanent magnet synchronous motor with limited rotation speed. Background Art

[0002] Permanent magnet synchronous motor (PMSM) occupies a key position in modern electromechanical transmission and is widely used in industrial robots, automated production, electric vehicles and other fields. Common control methods for permanent magnet synchronous motors mainly include: field-oriented control, direct torque control, and constant voltage-frequency ratio control. Among them, field-oriented control is the most commonly used and very efficient control strategy, which has been widely used in industry. Its principle is to convert the three-phase AC quantity of the motor into two-phase DC quantity through two coordinate transformations (Clark transformation and Park transformation) to achieve precise control of the motor. Field-oriented control usually includes current loop, angular velocity loop and angular displacement loop, and the current, angular velocity and angular displacement are adjusted by PI controller to achieve the required performance. The key to the FOC control algorithm is to control the current size and direction of the three-phase input to produce maximum torque and efficiency.

[0003] In the process of motor angular displacement control, a low-pass filter is usually used to plan the transition process of the motor's angular displacement and angular velocity. However, when the motor's single displacement adjustment is relatively large, the planned peak angular velocity will be relatively large. For the motor controller, since there is an upper limit to the motor speed it can control, when the planned peak angular velocity exceeds the upper limit of the speed that the controller can withstand, the closed-loop control system will be out of control. Summary of the invention

[0004] In view of the above problems, the present invention provides a speed-limited permanent magnet synchronous motor angular displacement servo control method, comprising the following steps: Step S1: Design a transition process, which includes three stages: starting, running at a constant speed, and braking: During the startup phase, the angular velocity is accelerated from 0 to the maximum allowable speed ω at a constant angular acceleration. max ; In the intermediate stage, at the maximum permissible speed ω max Constant operation; During the braking phase, the angular velocity is increased from the maximum allowable speed ω at a constant angular acceleration. max decelerate to 0; Determine the time of each phase and determine the planned movement amount based on the time of each phase, including the expected angular displacement i d , expected angular velocity oh d and the expected angular acceleration a d .

[0005] Step S2: Based on the movement volume planned in step S1, a mechanical loop anti-disturbance backstepping controller and a current loop controller are designed to achieve accurate tracking of the planned desired angular displacement and desired angular velocity of the permanent magnet synchronous motor by the angular displacement and angular velocity.

[0006] Based on the above technical solution, the constant angular acceleration is equal in magnitude during the starting and braking stages.

[0007] Based on the above technical solution, the time of each stage and the amount of exercise to be planned include: Let the starting and braking time be t , the intermediate uniform speed running time is , the acceleration is , determine the time of each stage: when hour, ;when hour, , is the target angle.

[0008] Define time points , determine the planned movement amount according to the time of each stage, including the expected angular displacement i d , expected angular velocity oh d and the expected angular acceleration a d ,like ,but , , ; like ,but , , ; like ,but , , ; like ,but , , .

[0009] Based on the above technical solution, step S2 specifically includes the following steps: Step S21: Design a mechanical loop anti-disturbance backstepping controller: First, define the angular tracking error: ; and take its derivative: ; Construct a virtual control law as ω, in order to achieve , the expected value is: ,in, , k 1 is a positive constant; Define angular velocity tracking error: , find the derivative: , where T l is the unknown load torque or interference torque, and J is the moment of inertia converted to the motor shaft; Use the extended state observer to estimate the unknown load torque or disturbance torque and define the disturbance , design a reduced-order extended state observer to estimate the disturbance σ:

[0010] Among them, 0< m <<1, z is the constructed intermediate variable, yes The estimated value of , ; Design expected torque value: , in, is a normal number.

[0011] Step S22, designing a PID controller of the current loop to achieve precise regulation of the motor output torque, Adjust to the desired torque , and thus achieve : Adopt i d =0 magnetic field oriented control method, according to Available , which can be written as: , in, i d is the d-axis current, i q is the q-axis current, P f is the stator winding permanent magnet flux amplitude, n p is the number of magnetic pole pairs on the motor rotor; The PI control algorithm with model compensation is used to adjust the d-axis and q-axis currents and input voltage and Can be designed as:

[0012] in, , , , , , Indicates the switching frequency of PWM.

[0013] The present invention also provides a permanent magnet synchronous motor angular displacement servo control device with limited speed, comprising: Transition module, the transition module is used to design the transition process, the transition process includes starting, constant speed and braking units: A starting unit, wherein the starting unit accelerates the angular velocity from 0 to the maximum allowable rotation speed ω at a constant angular acceleration max ; The uniform speed unit has a maximum allowable rotation speed ω max Constant operation; The brake unit completes the angular velocity from the maximum allowable speed ω at a constant angular acceleration max decelerate to 0; A planning module, which is used to determine the time of each stage and determine the planned movement amount according to the time of each stage, including the expected angular displacement i d , expected angular velocity oh d and the expected angular acceleration a d ; A controller design module is used to design a mechanical loop anti-disturbance backstepping controller and a current loop controller based on the movement volume planned by the planning module, so as to achieve accurate tracking of the planned desired angular displacement and desired angular velocity of the permanent magnet synchronous motor by the angular displacement and angular velocity.

[0014] Based on the above solution, the constant angular accelerations in the starting unit and the braking unit are equal in magnitude and opposite in direction.

[0015] The present invention also provides a controller, comprising a memory, a processor, and instructions stored in the memory and executable on the processor, wherein the processor is used to execute the above-mentioned method for angular displacement servo control of a permanent magnet synchronous motor with limited speed.

[0016] Compared with the prior art, the present invention has the following beneficial effects: through the design of the transition process and the design of the controller, the angular displacement and angular velocity of the motor can accurately track the planned expected angular displacement and expected angular velocity; the design of the closed-loop control system not only improves the stability and accuracy of the device during operation, but also significantly enhances the overall performance of the AC servo system under speed-limited conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A timing diagram of the transition process designed for the present invention; Figure 2 It is a principle block diagram of the closed-loop system of the discrete time domain robust speed controller proposed by the present invention; Figure 3 FIG. 4 is a schematic diagram of experimental results according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The following is a detailed description of an embodiment of a speed-limited permanent magnet synchronous motor angular displacement servo control method and device according to the present invention with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0019] The angular displacement servo system of the surface-mounted permanent magnet synchronous motor (SPMSM) can be written as: , Among them, the meaning of each parameter is shown in Table 1: Table 1 Meaning of motor parameters

[0020] For the angular displacement servo system of permanent magnet synchronous motor, the control goal is: design Shaft input voltage and The shaft input voltage causes the rotor angle Quickly adjust to the target angle , and during the adjustment process, the angular velocity of the motor rotation Not exceeding the set value ,Right now For all Established.

[0021] In order to achieve the control target, the present invention provides a speed-limited permanent magnet synchronous motor angular displacement servo control method. First, the transition process is designed, such as Figure 1 As shown, let the starting and braking time be t , the intermediate uniform speed running time is tmid , then the acceleration is , when hour, , when hour, .

[0022] Then, the planned movement amount, including the expected angular displacement, is determined based on the time of each stage. , expected angular velocity and the expected angular acceleration . Define the time point , then, there is like ,but , , ; like ,but , , ; like ,but , , ; like ,but , , .

[0023] Based on the design of the transition process, the controller is designed to achieve the angular displacement of the permanent magnet synchronous motor and angular velocity The expected angular displacement for planning and the desired angular velocity To perform precise tracking. First, design the mechanical loop self-disturbance rejection backstepping controller: Define angular tracking error: , Taking its derivative we get: , make is a virtual control law. , its expected value is: , in, is a normal number.

[0024] To achieve , define the angular velocity tracking error: , Taking its derivative we get: , because is an unknown load torque or disturbance torque, which will have an adverse effect on the control performance. In order to suppress this adverse effect, the disturbance is defined , here we use the reduced-order extended state observer to estimate it, and the designed reduced-order extended state observer can be written as: , Among them, 0< m <<1, is the constructed intermediate variable, yes It can be proved that when , .

[0025] Based on the disturbance estimation value of the extended state observer, the expected torque value can be designed: , in, is a normal number.

[0026] When the motor output torque Can be precisely adjusted to , then it can be achieved .

[0027] In order to achieve accurate regulation of the motor output torque, a PID controller for the current loop is designed. i d =0 magnetic field oriented control method, then according to Available , which can be written as , For the current regulation of the d-axis and q-axis, a PI control algorithm with model compensation is used. and Can be designed as: , in, , , , , , Indicates the switching frequency of PWM.

[0028] like Figure 2 As shown, first, according to the target angle of the rotor i r , perform trajectory planning, i.e. transition process design, and obtain the desired angular displacement , expected angular velocity and the expected angular acceleration ; , the P controller is proportional to the angle tracking error, and by choosing a suitable k 1 value, the controller's response speed to the error can be adjusted; by defining the disturbance , and use the reduced-order extended state observer to estimate, based on the disturbance estimate of the extended state observer, the expected torque value is designed T e * ;use i d =0 magnetic field oriented control method, according to the motor electromagnetic torque formula: ,but i q Can be used T e * express: ; Use PI control algorithm with model compensation to obtain the input voltage of d-axis and q-axis and , using the Inverse Park transformation, the calculated and The SVPWM module receives the three-phase PWM signal from the Inverse Park conversion module. The PWM signal controls the switching action of the MOSFET of each phase in the inverter, thereby generating an AC voltage for driving the motor. At the same time, the generated three-phase AC current signal is converted into a two-phase current signal by Clark / Park. i d and i q , and flows to the PI controller for calculation and , forming a closed loop; using the encoder to monitor the angular displacement signal of the motor, calculate the angular velocity, and feed the angular displacement and angular velocity back to the controller to update the error and adjust the output until the angular displacement reaches the desired value.

[0029] The design of the transition process and the controller in the present invention can significantly improve the closed-loop system stability of the AC servo system under speed limitation, ensuring good stability and accuracy even when facing speed limitation during the motor control process.

[0030] In order to verify the feasibility of the trajectory planning method and controller design method proposed in the present invention, experiments were carried out on a permanent magnet synchronous motor experimental device for demonstration.

[0031] The control goal is to make the angular displacement of the permanent magnet synchronous motor firstly adjusted from 0 rad to 100 rad in the positive direction, and the angular velocity does not exceed 20 rad / s during the process. The time for the angular velocity to accelerate from 0 rad / s to 20 rad / s is 0.5 s, and the time for decelerating from 20 rad / s to 0 rad / s is 0.5 s, and then reversely adjusted from 100 rad to 0 rad, and the angular velocity does not exceed -20 rad / s during the process. The acceleration and deceleration time of the angular velocity is also 0.5 s. The experimental results are shown in Figure 3 shown.

[0032] In the figure, a1 is the first process of the actual angular displacement, which means that the actual angular displacement can smoothly transition from 0 rad to 100 rad, a2 is the second process of the actual angular displacement, which means that the displacement does not change, and a3 is the third process of the actual angular displacement, which means that the angular displacement transitions from 100 rad back to 0 rad; b1 and b2 in the figure are the actual angular velocity change process when the motor rotates in the forward and reverse directions respectively. It can be seen that the actual angular velocity does not exceed the limit of ±20 rad / s during the entire movement process; A1 and A2 in the figure are the planned angular displacement transition from 0 rad to 100 rad and from 100 rad back to 0 rad, B1 and B2 are the planned angular velocity change process when the motor rotates in the forward and reverse directions respectively; C1, C2, C3, and C4 are the changes when the planned angular acceleration is not 0, and each angular acceleration is a fixed value. According to the results, it is found that there is a good consistency between the planned angular displacement and angular velocity and the actual angular displacement and angular velocity.

[0033] Specifically, the motor can smoothly transition according to the planned angular displacement, angular velocity and angular acceleration, while the angular velocity does not exceed the limit of ±20 rad / s, and the angular displacement and angular velocity can also track the planned trajectory well. This shows that the present invention can achieve smooth regulation of angular displacement, meet the control target requirements, and effectively control the angular velocity of the motor so that it does not exceed the set limit value. Therefore, the experimental results verify the feasibility and effectiveness of the transition process design method and controller design method proposed in the present invention.

[0034] The present invention also provides a permanent magnet synchronous motor angular displacement servo control device with limited speed, comprising: Transition module, the transition module is used to design the transition process, the transition process includes starting, constant speed and braking units: A starting unit, wherein the starting unit accelerates the angular velocity from 0 to the maximum allowable rotation speed ω at a constant angular acceleration max ; The uniform speed unit has a maximum allowable rotation speed ω max Constant operation; The brake unit completes the angular velocity from the maximum allowable speed ω at a constant angular acceleration max decelerate to 0; A planning module, which is used to determine the time of each stage and determine the planned movement amount according to the time of each stage, including the expected angular displacement i d , expected angular velocity oh d and the expected angular acceleration a d ; A controller design module is used to design a mechanical loop self-disturbance rejection backstepping controller and a current loop controller based on the movement volume planned by the planning module, so as to achieve accurate tracking of the planned desired angular displacement and desired angular velocity of the permanent magnet synchronous motor by the angular displacement and angular velocity.

[0035] Specifically, the constant angular accelerations in the starting unit and the braking unit are equal in magnitude and opposite in direction.

[0036] The present invention also provides a controller, comprising a memory, a processor, and instructions stored in the memory and executable on the processor, wherein the processor is used to execute the above-mentioned speed-limited permanent magnet synchronous motor angular displacement servo control method. The instructions may be stored in a computer-readable storage medium, and when the instructions are executed by the processor, the steps in the above-mentioned method embodiments may be implemented.

[0037] The present invention has been described with respect to the preferred embodiments mentioned above, but the scope of the present invention is not limited to such embodiments. The scope of the present invention is determined according to the following claims and may include various modifications and variations that are within the scope equivalent to the present invention.

Claims

1. A speed-limited permanent magnet synchronous motor angular displacement servo control method, characterized in that: The following steps are involved: Step S1: Design a transition process, which includes three stages: starting, running at a constant speed, and braking: During the startup phase, the angular velocity is accelerated from 0 to the maximum allowable speed ω at a constant angular acceleration. max ; In the intermediate stage, at the maximum permissible speed ω max Constant operation; During the braking phase, the angular velocity is increased from the maximum allowable speed ω at a constant angular acceleration. max decelerate to 0; Determine the time of each phase and determine the planned movement amount based on the time of each phase, including the expected angular displacement θ d , expected angular velocity ω d and the expected angular acceleration a d ; Step S2: Based on the movement volume planned in step S1, a mechanical loop anti-disturbance backstepping controller and a current loop controller are designed to achieve accurate tracking of the planned desired angular displacement and desired angular velocity of the permanent magnet synchronous motor by the angular displacement and angular velocity.

2. The method for controlling the angular displacement servo of a permanent magnet synchronous motor with limited speed according to claim 1, characterized in that: During the starting and braking phases, the constant angular accelerations are equal in magnitude and opposite in direction.

3. The method for controlling the angular displacement servo of a permanent magnet synchronous motor with limited speed according to claim 1, characterized in that: The time and amount of exercise planned for each stage include: Let the starting and braking time be τ , the intermediate uniform speed running time is , the acceleration is , determine the time of each stage: when hour, ;when hour, , is the target angle; Define time points , determine the planned movement amount according to the time of each stage, including the expected angular displacement θ d , expected angular velocity ω d and the expected angular acceleration a d ,like ,but ， ， ； like ,but ， ， ； like ,but ， ， ； like ,but ， ， 。 4. The method for controlling the angular displacement servo of a permanent magnet synchronous motor with limited speed according to claim 1, characterized in that: Step S2 specifically includes the following steps: Step S21: Design a mechanical loop anti-disturbance backstepping controller: First, define the angular tracking error: ; and take its derivative: ; Construct a virtual control law as ω, in order to achieve , the expected value is: ,in, , k1 is a positive constant; Define angular velocity tracking error: , find the derivative: , where T l is the unknown load torque or interference torque, and J is the moment of inertia converted to the motor shaft; Use the extended state observer to estimate the unknown load torque or disturbance torque and define the disturbance , design a reduced-order extended state observer to estimate disturbances σ : Where 0 < μ << 1, z is the constructed intermediate variable, yes The estimated value of , ; Design expected torque value: ， in, is a positive constant; Step S22, designing a PID controller of the current loop to achieve precise regulation of the motor output torque, Adjust to the desired torque , and thus achieve ,include: use i d =0 magnetic field oriented control method, according to Available : ， in, i d is the d-axis current, i q is the q-axis current, Ψ f is the stator winding permanent magnet flux amplitude, n p is the number of magnetic pole pairs on the motor rotor; The PI control algorithm with model compensation is used to adjust the d-axis and q-axis currents and input voltage and Can be designed as: in, , , , , , Indicates the switching frequency of PWM.

5. A speed-limited permanent magnet synchronous motor angular displacement servo control device, characterized in that: include: Transition module, the transition module is used to design the transition process, the transition process includes starting, constant speed and braking units: A starting unit, wherein the starting unit accelerates the angular velocity from 0 to the maximum allowable rotation speed ω at a constant angular acceleration max ; The uniform speed unit has a maximum allowable rotation speed ω max Constant operation; The brake unit completes the angular velocity from the maximum allowable speed ω at a constant angular acceleration max decelerate to 0; A planning module, which is used to determine the time of each stage and determine the planned movement amount according to the time of each stage, including the expected angular displacement θ d , expected angular velocity ω d and the expected angular acceleration a d ; A controller design module is used to design a mechanical loop self-disturbance rejection backstepping controller and a current loop controller based on the movement volume planned by the planning module, so as to achieve accurate tracking of the planned desired angular displacement and desired angular velocity of the permanent magnet synchronous motor by the angular displacement and angular velocity.

6. The angular displacement servo control device of a permanent magnet synchronous motor with limited speed according to claim 5, characterized in that: The constant angular accelerations in the starting unit and the braking unit are equal in magnitude and opposite in direction.

7. A controller comprising a memory, a processor, and instructions stored in the memory and executable on the processor, characterized in that: The processor is used to execute a speed-limited permanent magnet synchronous motor angular displacement servo control method as described in any one of claims 1-4.

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