阅读说明：本技术 一种稳定时间可调的永磁同步电机滑模控制方法 (Sliding mode control method for permanent magnet synchronous motor with adjustable stabilization time ) 是由 丁世宏 王磊 马莉 于 2021-07-14 设计创作，主要内容包括：本发明公开了一种稳定时间可调的滑模控制器设计方法,用于永磁同步电机的调速控制。其主要步骤如下：步骤1,基于矢量控制策略,实现速度环和电流环的解耦,采用令的控制方法,建立速度环的数学模型；步骤2,利用预定时间稳定的滑模控制算法,设计永磁同步电机的速度环控制器；步骤3,在预定时间稳定的滑模控制器的基础上引入扰动观测器进行前馈补偿,以此减小控制系统的抖振。本发明所提出的控制方法不仅能使系统状态在预定的时间T之内收敛到平衡点,而且可以改善传统滑模控制方法固有的抖振问题,最终的复合控制器具有良好的跟踪精度和抗扰性能。(The invention discloses a design method of a sliding mode controller with adjustable stabilization time, which is used for speed regulation control of a permanent magnet synchronous motor. The method mainly comprises the following steps: step 1, decoupling of a speed loop and a current loop is realized based on a vector control strategy, and an order is adopted The control method of (3) establishing a mathematical model of the velocity loop; step 2, designing a speed loop controller of the permanent magnet synchronous motor by using a sliding mode control algorithm with stable preset time; and 3, introducing a disturbance observer to perform feedforward compensation on the basis of the sliding mode controller with stable preset time, so as to reduce buffeting of the control system. The control method provided by the invention not only can make the system state converge to the balance point within the preset time T, but also can improve the buffeting problem inherent in the traditional sliding mode control method, and the final composite controller has good tracking accuracy and anti-interference performance.)

1. A sliding mode control method of a permanent magnet synchronous motor with adjustable stabilization time is characterized by comprising the following steps:

step 1: based on a vector control strategy, decoupling of a speed loop and a current loop is realized; adopt and orderThe control method of (3) establishing a mathematical model of the velocity loop;

step 2: the actual rotation speed omega of the permanent magnet synchronous motor is compared with the expected rotation speed omega_rDesigning a preset time controller by using the difference as a sliding variable;

and step 3: and designing a nonlinear disturbance observer, and performing feedforward compensation by using a disturbed observation value to enhance the anti-interference capability of the system and reduce the buffeting of the system.

2. The sliding mode control method for the permanent magnet synchronous motor with the adjustable stable time according to claim 1, characterized in that in step 1, the mathematical model of the speed loop is as follows:

wherein n is_pThe number of the pole pairs of the motor is,is a magnetic linkage, J is a moment of inertia,q-axis current, B viscous damping, T_LIs the load torque; in step 2, the slip form is taken as follows

s＝ω-ω_r (2)

Wherein, omega is the actual rotating speed of the motor, omega_rTo expect the rotation speed, the formula (1) is combined

Wherein the content of the first and second substances,for the system (3), a sliding mode controller with stable preset time is designed as follows

3. The sliding mode controller of the permanent magnet synchronous motor with adjustable stabilization time designed in the claim 2 is characterized in that the parameters of the controller require that: ζ ≧ d (T) l, ζ is a bounded normal number, T is a preset maximum system settling time, α, β, p, q, k are normal numbers to be designed and satisfy kp <1, kq >1, sign function sign(s) satisfies

Gamma is a constant calculated according to the parameters and satisfies

Wherein the content of the first and second substances,and because ofIt can be seen that the desired current of the q-axisI.e. the actual speed loop controller may be designed as follows

4. The sliding mode control method for the permanent magnet synchronous motor with the adjustable stabilization time according to claim 1, wherein the system state can be stabilized within a preset time T.

5. The sliding mode control method of the permanent magnet synchronous motor with the adjustable stable time according to claim 1, characterized in that in step 3, a disturbance observer is designed to observe unknown disturbance; the disturbance observer is as follows

Wherein, λ is the observation gain,is the observed value of d (t) in the system (3).

6. A stabilizer according to claim 1The sliding mode control method of the permanent magnet synchronous motor with adjustable timing is characterized in that in step 3, a disturbance observation value is usedCompensating the unknown disturbance d (t) to the controller u to counteract the influence of the system; in this case, the controller (4) may be further optimized

According toAt this time, the desired current of the q-axisI.e. the actual speed loop controller is

The final composite controller has better control precision and robustness.

Technical Field

The invention relates to the field of speed regulation control of a permanent magnet synchronous motor, and mainly comprises a design method of a sliding mode device of the permanent magnet synchronous motor with adjustable stabilization time.

Background

The permanent magnet synchronous motor becomes the mainstream choice in the current servo speed regulation system by virtue of the characteristics of high efficiency, low noise, small volume, large starting torque, high response speed and the like, and is widely applied to the fields of robots, aerospace, medical instruments, industrial automation and the like. In recent years, under the strong promotion of national policies, the electric automobile industry develops vigorously, which undoubtedly brings wider application prospects to the permanent magnet synchronous motor. However, the permanent magnet synchronous motor is a multivariable, nonlinear and strongly coupled time-varying nonlinear system, and the traditional linear PI control is difficult to achieve the control requirement of high performance. In order to obtain higher control performance, many scholars apply sliding mode variable structure control to a permanent magnet synchronous motor speed regulating system.

Conventional linear sliding modes can only guarantee the progressive stability of the system, which means that the system state may not converge to zero in a limited time. And a nonlinear term is added into a linear sliding mode surface of the terminal sliding mode, so that the system realizes finite time convergence. However, none of the above control methods clearly reflects the relationship between the controller parameters and the actual settling time, and the convergence speed of the system can only be changed vaguely by modifying the controller parameters, and the settling time cannot be set directly in the controller explicitly.

Disclosure of Invention

The invention provides a sliding mode control method of a permanent magnet synchronous motor with adjustable stabilization time. In addition, a nonlinear load disturbance observer is introduced for feedforward compensation, so that the anti-interference capability of the system is improved, and the buffeting of the system is reduced.

The technical scheme adopted by the invention comprises the following specific steps:

step 1: and realizing the decoupling of the speed loop and the current loop based on a vector control strategy. Adopt and orderThe mathematical model of the speed loop is established.

Step 2: the actual rotation speed omega of the permanent magnet synchronous motor is compared with the expected rotation speed omega_rThe difference is used as a sliding variable, and a preset time controller is designed.

And step 3: and designing a nonlinear disturbance observer, and performing feedforward compensation by using a disturbed observation value to enhance the anti-interference capability of the system and reduce the buffeting of the system.

Further, the mathematical model of the velocity loop in step 1 can be described as:

wherein n is_pThe number of the pole pairs of the motor is,is the flux linkage, J is the moment of inertia, i_qQ-axis current, B viscous damping, T_LIs the load torque.

Further, in step 2, the sliding mode is selected as follows:

s＝ω-ω_r (2)

wherein, omega is the actual rotating speed of the motor, omega_rAt the desired rotational speed. The combination formula (1) shows

Wherein the content of the first and second substances,next, we will design the controller u to make the sliding variable s possible at a predetermined timeConvergence to zero within T.

The following controller is designed for the system (3)

Where, ζ ≧ d (t) | and ζ is a bounded normal number. T is a preset maximum stable time of the system, alpha, beta, p, q, k are normal numbers to be designed and satisfy kp <1, kq >1, and a sign function sign(s) satisfies

Gamma is a constant calculated according to the parameters and satisfies

Wherein the content of the first and second substances,

since d (t) is often not precisely known in real-world conditions, choosing too large a ζ increases the buffeting of the system. To further reduce system buffeting, in step 3, a non-linear disturbance observer is designed for the system (3) to obtain observed values of unknown disturbance d (t)

Where λ is the observation gain. Observing the disturbanceTo the controller u to counteract the effect of the disturbance d (t) on the system,at this time

Further, desired current of q-axisI.e. the actual speed loop controller

The finally obtained composite controller has good control precision and robustness, and meanwhile, the system can reach a stable state at a specified time T.

The invention has the following beneficial effects:

1) compared with the traditional sliding mode control algorithm, the method can preset time T in advance among controller parameters, and the rotating speed of the motor can reach the expected rotating speed within the time T and enter a stable state. The method has good anti-interference performance, the rotating speed of the motor is slightly reduced under the condition of sudden load, and the rotating speed can be quickly increased back to the expected rotating speed.

2) According to the invention, the load disturbance observer is introduced to perform feedforward compensation on the observed load disturbance, so that the speed loop controller can dynamically adjust and control the output of the speed loop controller according to the load size, and the buffeting during system switching is reduced.

3) The controller designed by the invention has good control precision and robustness, simple principle and easy realization in engineering.

Drawings

Fig. 1 is an overall block diagram of a vector control system of a permanent magnet synchronous motor according to the present invention.

Fig. 2 is a simulation model of the sliding mode controller of the present invention that is stable for a predetermined time.

FIG. 3 is a diagram of a simulation model of a disturbance observer.

Fig. 4 is a waveform comparison diagram of observed values and actual values of a disturbance observer.

Fig. 5 is a waveform of the motor rotation speed under the control of the sliding mode controller of the permanent magnet synchronous motor with stable predetermined time when different parameters T are selected.

Fig. 6 is a waveform diagram of q-axis current of the motor under the control of the sliding mode control method of the permanent magnet synchronous motor with stable predetermined time.

Detailed Description

The invention discloses a permanent magnet synchronous motor sliding mode control method with stable preset time, which is used for speed regulation control of a permanent magnet synchronous motor. In order to make the objects, embodiments and advantages of the present invention clearer and clearer, specific implementation steps of the present invention will be described in detail through specific examples and drawings.

Fig. 1 is an overall block diagram of a vector control system of a permanent magnet synchronous motor according to the present invention. It comprises the following parts: the device comprises a permanent magnet synchronous motor module, an inverter module, an SVPWM module, a current loop module, a speed loop module and a coordinate transformation module.

Table 1 shows the specific parameters of the permanent magnet synchronous machine used in the example.

TABLE 1 PERMANENT-MAGNET SYNCHRONOUS MOTOR PARAMETER TABLE

The specific implementation steps are as follows:

step 1: and constructing a mathematical model of the speed loop of the permanent magnet synchronous motor in a d-q coordinate system.

In a d-q coordinate system, a mathematical model of a surface-mounted permanent magnet synchronous motor speed ring can be described as follows:

where ω is the mechanical angular velocity of the motor, n_pThe number of the pole pairs of the motor is,is the flux linkage of the motor, and J is the motor rotationInertia, i_qQ-axis current of stator winding of permanent magnet synchronous motor, B viscous damping, T_LIs the load torque.

Step 2: and designing a speed loop controller with stable preset time by using a preset time stability control algorithm.

Selecting the actual rotation speed omega of the motor and the expected rotation speed omega of the motor_rThe difference being a sliding variable, i.e.

s＝ω-ω_r (11)

By deriving formula (11), the result is obtained

Wherein the content of the first and second substances,for the system (12), a controller is designed for the following predetermined time stabilization:

where, ζ ≧ d (t) | and ζ is a bounded normal number. T is a preset maximum stable time of the system, alpha, beta, p, q, k are normal numbers to be designed and satisfy kp <1, kq >1, and a sign function sign(s) satisfies

Gamma is a constant calculated according to the parameters and satisfies

Wherein the content of the first and second substances,let Lyapunov function V(s) ═ s | be obtainedAnd the criterion of the stability of the Lyapunov preset time is met. Thus, the system can reach a steady state within a predetermined time T. And because ofIt can be seen that the desired current of the q-axisI.e. the actual speed loop controller may be designed as follows

And step 3: and designing a nonlinear disturbance observer, and performing feedforward compensation by using the observed value of the disturbance.

Zeta is used as the upper constant bound for d (t) in the controller to eliminate the effect of d (t) on the system. In a practical permanent magnet synchronous motor system, the disturbance d (t) is a time-varying quantity, and during the actual operation of the permanent magnet synchronous motor, especially when the load torque is suddenly changed, the variation of the disturbance d (t) can be large, and a larger upper-bound parameter ζ has to be selected to suppress the disturbance. However, too large a choice of zeta parameter may increase the buffeting of the system and adversely affect the stability of the system. Aiming at the problem, the invention further optimizes the controller by introducing a nonlinear load disturbance observer.

For the system (12), a disturbance observer is designed as follows

Wherein, λ is the observation gain,is the observed value of d (t) in the system (12) becauseKnowing the load torque T_LObserved value of (2)FIG. 4 shows the load torque T_LIs compared with the observed value of the load torque, and the observed value of the load torque can be seen in the graphCan be compared with the actual value T_LAccurate tracking is achieved.

Next, perturbing the observationCompensating to the controller u to counteract the effect of the unknown disturbance d (t) on the system, in which case the controller (13) may be further optimised

According toIn this case, the actual speed loop controller is

In order to more clearly illustrate the control effect of the invention, a simulation model is built in Simulink. The basic parameters of the permanent magnet synchronous machine are shown in table 1. In order for the control system to achieve predetermined time stability, i.e., to achieve a desired speed of the PMSM at any given time, the controller parameter selection principle needs to satisfy α, β, p, q, k >0 and kp <1, kq > 1. In the simulation experiment, the controller parameters are selected as follows: α is 1, β is 1, p is 0.5, q is 3, and k is 0.5, and is calculated from formula (15), and parameter γ is 3.1. The nonlinear disturbance observer gain is selected as: λ 5000. In order to verify whether the controller designed in the invention can enable the motor to reach a stable state within any given time, three groups of simulation experiments are designed, and the preset maximum stable time T is respectively set to be 0.05s, 0.10s and 0.15 s.

In the simulation example, the desired rotation speed is set to 1000 r/min. In order to test the anti-interference performance of the permanent magnet synchronous motor control system under the scenes of sudden load, variable load and the like, load torque T_LGiven as follows:

the simulation results are shown in fig. 4-6. FIG. 4 shows the load torque T_LIs compared with the observed value, and it can be seen from the graph that the load torque T is_LIs a quantity which changes along with time, and the observer can realize accurate tracking. FIG. 5 is a comparison of the waveforms of the rotational speeds at different times T selected by the controller, and it can be seen that the motor can always reach the desired rotational speed within a predetermined time T and enter a steady state; under the condition of facing sudden load, the motor can realize smaller rotating speed drop; at the same time, at a time-varying load T_LUnder the action, the rotating speed of the motor can be kept at the expected rotating speed. Fig. 6 is a comparison graph of q-axis current waveforms of the motor under the respective actions of the controller (16) and the controller (19), and it can be seen that the controller (19) significantly reduces the buffeting of the system compared with the controller (16) due to the introduction of the disturbance observer. In conclusion, it can be seen that the composite controller designed by the invention not only can realize stability in a preset time, but also has strong robustness and anti-interference performance.

Compared with the traditional sliding mode control method, the design method of the permanent magnet synchronous motor sliding mode device with the adjustable stabilization time has the advantages that: (1) the preset maximum system stability time is used as a controller parameter, the stability time of the motor reaching the expected rotating speed is dynamically adjusted through explicit assignment, and meanwhile, the designed controller is high in control precision and strong in robustness, and can still achieve a good control effect under the scenes of sudden load increase, variable load and the like; (2) by introducing the nonlinear disturbance observer and performing feedforward compensation on the controller by using the disturbance observation value, the buffeting problem existing in the traditional first-order sliding mode is greatly weakened; (3) the controller designed by the invention has a simple control structure and is easy to realize in engineering.

The above-listed detailed description is only a specific description of a possible embodiment of the present invention, and it is not intended to limit the scope of the present invention, and various changes, modifications, substitutions and alterations to the embodiments without departing from the principle and spirit of the present invention should be included in the scope of the present invention.