Adaptive super-spiral permanent magnet synchronous motor-based anti-interference control method

Abstract

The invention relates to an anti-interference control method for a permanent magnet synchronous motor, in particular to an anti-interference control method for a permanent magnet synchronous motor based on a self-adaptive super-spiral permanent magnet synchronous motor, which comprises the following steps of: estimating the total disturbance Z (t) of the motor through a self-adaptive super-spiral sliding mode observer according to the difference # imgabs1 # between a motor rotating speed set value # imgabs0 # and the actual rotating speed omega m of the motor; and substituting # imgabs2 # and Z (t) into a non-singular fast terminal sliding mode controller at the same time to obtain a stator current q-axis component expected value # imgabs3 # current loop control part adopts a control mode that a quasi-proportional resonance controller is connected with a PI controller in parallel. According to the difference of the current components of the alpha axis and the beta axis under the static coordinate, the components of the reference voltage of space vector pulse width modulation on the alpha axis and the beta axis are obtained, and then motor driving is achieved. According to the invention, the problems of large current harmonic wave, poor rotating speed dynamic and static response, large overshoot and poor anti-interference performance under the control mode of the traditional PI controller can be solved.

Description

Technical Field

[0001] The invention relates to a speed control method for a permanent magnet synchronous motor, and in particular to an anti-disturbance control method based on an adaptive super-helical permanent magnet synchronous motor. Background Art

[0002] Permanent magnet synchronous motors are widely used in new energy vehicles, industrial robots, aerospace organizations and some fields that require high-precision positioning due to their advantages of high power density, high energy efficiency and high reliability. Traditional PMSM control systems usually use dual closed-loop PI control, namely speed loop and current loop. The speed loop controls the motor speed through the PI controller, and the current loop controls the motor current through the PI controller. With the development of science and technology and industrial upgrading, traditional PID control can no longer meet today's control accuracy requirements. At present, in addition to PID control, the speed loop control methods of permanent magnet synchronous motors that are often studied include: neural network control, fuzzy control, robust control, anti-disturbance control, adaptive control and sliding mode control, etc., and the current loop is predictive control and proportional resonance control, etc.

[0003] Sliding mode control is essentially a special nonlinear control method, which is characterized by the discontinuity of control. It can make the state of the controlled system move on a predetermined sliding surface. The selection and design of the sliding surface are independent of the system parameters and external disturbances. Therefore, sliding mode control has the excellent performance of being insensitive to the system's unmodeled dynamics, parameter changes and external disturbances, and is widely used in the field of permanent magnet synchronous motor control.

[0004] However, due to the discontinuous switching of the sliding mode control itself, the system chattering is inevitable, which has a great impact on the control performance. At the same time, due to the influence of uncertain factors such as its own parameters and load disturbances during operation, it is a relatively difficult problem to achieve high-precision control of the permanent magnet synchronous motor. How to achieve high-precision control of permanent magnet synchronous motors is of great significance in industry.

[0005] The traditional dual-loop PI controller is replaced by a speed loop adaptive super-helical sliding mode observer-non-singular fast terminal sliding mode composite controller, and the current loop PI controller is replaced by a proportional-quasi-proportional resonant controller. This can improve problems such as poor speed response, excessive overshoot, weak anti-interference, and large current harmonic components. Summary of the invention

[0006] The purpose of the present invention is to provide an anti-disturbance control method based on an adaptive super-helical permanent magnet synchronous motor, which minimizes the interference caused by the perturbation of motor parameters. At the same time, the coordinate rotation is reduced, thereby reducing the difficulty of implementing the control algorithm and reducing the interference of unknown factors on the operation of the motor. The method has been successfully applied to a surface-mounted permanent magnet synchronous motor, achieving small overshoot, small steady-state error, and strong anti-interference.

[0007] The technical solution of the present invention comprises the following steps:

[0008] An anti-disturbance control method based on adaptive super-helical permanent magnet synchronous motor, the steps of the method are as follows

[0009] Step 1: Model the dynamic model of the surface-mounted permanent magnet synchronous motor with disturbance;

[0010] Step 2: Design a current loop proportional-quasi-proportional resonant controller;

[0011] Step 3: According to the dynamic model, an adaptive super-helical perturbation sliding mode observer is designed, and together with a non-singular fast terminal sliding mode controller, a speed loop composite controller is formed;

[0012] Step 4: After the inner and outer double closed-loop controllers are designed, it is necessary to perform static coordinate transformation and anti-synchronous rotating coordinate transformation on the current to connect them into a complete double closed-loop control solution. Therefore, it is necessary to design Clark and I Park transformation modules.

[0013] 2. Further, in step 1, the dynamic model of the surface-mounted permanent magnet synchronous motor with disturbance is specifically:

[0014]

[0015] Among them, J is the moment of inertia; B is the damping coefficient; TL is the load torque; ωm is the mechanical angular velocity of the motor; Δe, Δl, Δb are the unknown bounded disturbances such as parameter perturbation, friction and load torque, respectively, and Z(t)=TL-JiqΔe+JΔl+JΔbωm is the total disturbance of motor parameter perturbation, friction and load torque.

[0016] 3. Further, in step 2, the specific proportional-quasi-proportional resonant controller transfer function is:

[0017]

[0018] Kp and Kr are the proportional gain coefficient and the resonant gain coefficient respectively; ω0 is the resonant frequency; ωc is the cutoff frequency, which characterizes the response speed of the controller to track the reference signal.

[0019] 4. Further, in step 3, the specific adaptive super-helical perturbation sliding mode observer can be expressed as:

[0020]

[0021] in, and for and The observed value of and is the derivative of ωm and Z(t); Te is the electromagnetic torque; k(.) is the adaptive function given by claim 5; sign(.) is the sign function; It is the difference between the set speed and the actual speed.

[0022] 5. Further, in step 3, the adaptive function is specifically expressed as:

[0023]

[0024] Where Δ represents the scaling factor (Δ>0).

[0025] 6. Further, in step 3, the non-singular fast terminal sliding mode controller obtains the expected value of the q-axis component of the motor stator current according to the following formula:

[0026]

[0027] 7. Further, in step 4, the Clark transformation and IPark transformation matrices are specifically:

[0028]

[0029] Among them, θ e is the motor electrical angle.

[0030] The advantages and positive effects of the present invention are as follows:

[0031] 1. Compared with the traditional PI controller, the proportional-proportional resonant current loop controller used in the present invention does not contain feedforward compensation and decoupling loops related to motor parameters. Therefore, the method minimizes the interference caused by motor parameter perturbation. At the same time, the coordinate rotation is reduced, thereby reducing the difficulty of implementing the control algorithm.

[0032] 2. In the speed loop control link, the present invention uses a non-singular fast terminal sliding mode controller, which has better control effect than the PI controller and reduces the chattering phenomenon of the sliding mode control. At the same time, an adaptive super-helical sliding mode observer is used to accurately observe the total disturbance and compensate it in the control to achieve anti-disturbance control, reducing the interference of unknown factors on the motor operation.

[0033] 3. The simulation results verify that the permanent magnet synchronous motor anti-disturbance control algorithm based on the adaptive super-helical sliding mode disturbance observer can be successfully applied to the surface-mounted permanent magnet synchronous motor, with small overshoot, small steady-state error and strong anti-disturbance, which verifies the effectiveness and superiority of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The control block diagram of the permanent magnet synchronous motor shown in the present invention;

[0035] Figure 2 Proportional-quasi-proportional resonant controller control block diagram;

[0036] Figure 3 Speed ​​loop compound control structure;

[0037] Figure 4 Motor step simulation curve;

[0038] Figure 5 Speed ​​error curve;

[0039] Figure 6 Three-phase current;

[0040] Figure 7 Comparison of disturbance observer performance. DETAILED DESCRIPTION

[0041] The present invention is further described in detail below with reference to the accompanying drawings and examples.

[0042] This case provides a dual closed-loop vector control solution for a surface-mounted permanent magnet synchronous motor based on an adaptive super-helical sliding mode observer. The control block diagram is shown in the figure. Figure 1 As shown. It includes the following steps:

[0043] (1) Establishment of a surface-mounted permanent magnet synchronous motor dynamics model with disturbance

[0044] Assuming that the adopted surface-mounted permanent magnet synchronous motor has negligible cross-coupled magnetic saturation, structural asymmetry, iron loss, magnet eddy current loss and harmonics in the description functions of winding, rotor anisotropy and magnet coercivity, the dynamics of the surface-mounted permanent magnet synchronous motor in the rotor dq coordinates can be described as follows:

[0045] The stator voltage equation is expressed as:

[0046]

[0047] The stator flux equation is:

[0048]

[0049] Substituting the stator flux equation into the stator voltage equation, the complete stator voltage equation is:

[0050]

[0051] Wherein, ud and uq are the dq axis components of the stator voltage, id and iq are the dq axis components of the stator current, R is the stator resistance, Ψ d and qis the dq axis component of the stator flux; ωe is the electrical angular velocity; Ld and Lq are the dq axis inductance components respectively; Ψ f is the permanent magnet flux; p is the differential operator.

[0052] The electromagnetic torque equation can be written as:

[0053]

[0054] Since this paper uses a surface-mounted three-phase permanent magnet synchronous motor and uses a control strategy of id = 0, Ld = Lq, id = 0. Therefore, equation (5) should be expressed as:

[0055]

[0056] The mechanical motion equation of the motor is expressed as:

[0057]

[0058] Where, J is the moment of inertia; B is the damping coefficient; TL is the load torque; ωm is the motor mechanical angular velocity.

[0059] Considering the PMSM operation disturbance, including the influence of motor parameter perturbation, friction and load torque, the mechanical motion equation is changed to the following form:

[0060]

[0061] Wherein, Δe, Δl, and Δb are the uncertain factors of the corresponding terms and are bounded factors, and Z(t)=TL-JiqΔe+JΔl+JΔbωm is the total disturbance of motor parameter perturbation, friction, and load torque.

[0062] (2) Design of current loop proportional-quasi-proportional resonant controller

[0063] The proportional-quasi-proportional resonant controller is based on and the output of the speed controller Obtained by inverse Park and The three-phase current of the motor obtained by the sensor is converted into i by Clark transformation α and i β The difference between the motor α axis reference voltage is taken as input. and β-axis reference voltage Controller as output.

[0064] The ideal PR controller transfer function and its gain function are shown below:

[0065]

[0066] Among them, Kp and Kr are the proportional gain coefficient and the resonant gain coefficient respectively; ω0 is the resonant frequency.

[0067] Obviously, the gain of the PR controller at ω0 is infinite, and the gain at other frequencies is small, which can achieve zero steady-state error tracking of the current at a specific frequency. However, in the actual operation of the motor, due to the influence of sampling error, model error, motor load change, speed change and other factors, the resonant angle of the three-phase current is changing. Therefore, we change the ideal proportional resonant controller into a quasi-proportional resonant controller, allowing the resonant angle frequency to change within a certain range. The transfer function of the quasi-proportional resonant controller is:

[0068]

[0069] Where ωc is the cut-off frequency.

[0070] The ideal PR controller can only perfectly track the current of the natural frequency. The QPR controller further increases the bandwidth of the ideal PR controller. However, when there is a large disturbance in the system, it will still have a great impact. Therefore, in this paper, the current loop control adopts a control structure in which quasi-PR control and PI control are connected in parallel, namely PI-QPR control. The control block diagram is shown in the figure. Figure 2 shown.

[0071] (3) According to the dynamic model, an adaptive superhelical perturbation sliding mode observer is designed, and together with a non-singular fast terminal sliding mode controller, a speed loop composite controller is formed.

[0072] The PMSM system state variables are defined as:

[0073]

[0074] Among them, ω r For a given speed.

[0075] Combining the state variables with the motor motion equation, we get the following equation:

[0076]

[0077] The new non-singular fast terminal sliding surface is proposed as follows:

[0078]

[0079] Taking the derivative of the sliding surface, we get:

[0080]

[0081] in, a>0, b>0.

[0082] Considering that the traditional approach rate has slow convergence speed and jitter problems, this paper designs an improved approach rate to effectively improve the system response speed and suppress system jitter. The improved approach rate is shown in the following formula:

[0083]

[0084] Among them, k1>0, k2>0, k3>0, 0<γ2<γ1<1.

[0085] Combining the two equations, the new sliding mode control rate is as follows:

[0086]

[0087] It can be obtained from the control rate that in order to ensure accurate and effective control, the derivative term of the unknown disturbance is still missing. Therefore, the present invention designs an adaptive super-helical sliding mode observer to observe the disturbance and perform disturbance compensation control.

[0088] According to the surface-mounted permanent magnet synchronous motor model with disturbance, the disturbance is regarded as the extended system state, so the extended state equation is as follows:

[0089]

[0090] d is the time derivative of the lumped disturbance Z(t).

[0091] Using the adaptive super-helix algorithm, an adaptive super-helix sliding mode observer can be designed:

[0092]

[0093] in, and for and The observed value of and is the derivative of ωm and Z(t); Te is the electromagnetic torque; k(.) is the adaptive function; sign(.) is the sign function; It is the difference between the set speed and the actual speed.

[0094] k(.) is given by:

[0095]

[0096] The specific combination structure of the adaptive super-helical sliding mode observer and the non-singular fast terminal sliding mode speed controller is as follows: Figure 3 shown.

[0097] (4) Nesting the speed loop and current loop into a complete dual-loop structure

[0098] The speed loop is set according to the motor speed and motor speed ω m difference The total disturbance Z(t) of the motor is estimated by the adaptive super-helical sliding mode observer. Substitute Z(t) and Z(t) into the non-singular fast terminal sliding mode controller to obtain the expected value of the q-axis component of the stator current After and The inverse Park transformation is performed together to obtain one item of the current loop input. The other item of the current loop input is obtained by Clark transformation of the three-phase current output by the inverter. The inverse Park and Clark transformation matrix is ​​shown below:

[0099]

[0100] Among them, θ e The electrical angle of the motor

[0101] Simulation verification and analysis

[0102] In order to verify the feasibility and effectiveness of the control scheme proposed in this invention, a complete system model was built in the Simulink environment using MATLAB simulation software. The parameters of the permanent magnet synchronous motor in the simulation are R = 2.875Ω, L d =L q =8.5mH,Ψ f =0.175Wb, p=4, J=0.001kg·m 2 , B = 0. Among them, the controller and observer parameters are k r =20,ω c =0.628rad / s, a=0.005, b=0.0004, k=35, j=27, m=9, n=5, k1=99, k2=4000000, k3=0.01, γ1=0.5, γ2=0.1, Δ=2000000.

[0103] The system sets the motor speed to 10 rad / s, and increases the load disturbance from 0N to 1.27N at 0.55. The simulation curve is as follows: Figure 4 As shown in the figure, it can be seen that the control scheme proposed by the present invention has an overshoot of 0.0026, an adjustment time of 0.0241s, and an offset after disturbance of 0.0944 during step start; while the overshoot under PI control is 1.0387, the adjustment time is 0.0728s, and the offset after disturbance is 3.6127. It can be seen that the control scheme proposed by the present invention has obvious advantages.

[0104] Figure 5The speed error, the steady-state error peak value of the control scheme of the present invention is 0.0016, and the PI control is 0.0029, and the steady-state performance is further improved; Figure 6 This is a comparison diagram of the three-phase current during operation. The three-phase current under the control of the present invention has a better waveform.

[0105] Figure 7 The disturbance observed by the adaptive super-helical sliding mode disturbance observer is compared with that observed by the common sliding mode observer. The observer used in the present invention can not only converge to the actual disturbance more quickly, but also has higher accuracy and better performance.

[0106] In summary, the control scheme proposed in the present invention can achieve higher precision and higher performance permanent magnet synchronous motor speed control.

Claims

1. A method for anti-disturbance control of an adaptive super-helical permanent magnet synchronous motor, characterized in that: The method comprises the following steps: Step 1: Model the dynamic model of the surface-mounted permanent magnet synchronous motor with disturbance; Step 2: Design a current loop proportional-quasi-proportional resonant controller; Step 3: According to the dynamic model, an adaptive super-helical perturbation sliding mode observer is designed, and together with a non-singular fast terminal sliding mode controller, a speed loop composite controller is formed; Step 4: After the inner and outer dual closed-loop controllers are designed, it is necessary to perform stationary coordinate transformation and anti-synchronous rotating coordinate transformation on the current to connect them into a complete dual closed-loop control solution; therefore, it is necessary to design Clark and IPark transformation modules.

2. The method for anti-disturbance control of an adaptive super-helical permanent magnet synchronous motor according to claim 1 is characterized in that: In step 1, the dynamic model of the surface-mounted permanent magnet synchronous motor with disturbance is specifically: Where, J is the moment of inertia; B is the damping coefficient; T L is the load torque; ω m is the motor mechanical angular velocity; Δe, Δl, Δb are the unknown bounded disturbances such as parameter perturbation, friction and load torque, respectively. Z(t)=T L -Ji q Δe+JΔl+JΔbω m It is the total disturbance of motor parameter perturbation, friction and load torque.

3. The anti-disturbance control method based on adaptive super-helical permanent magnet synchronous motor according to claim 1 is characterized in that: In step 2, the specific proportional-quasi-proportional resonant controller transfer function is: K p and K r are the proportional gain coefficient and the resonant gain coefficient respectively; ω0 is the resonant frequency; ω c is the cut-off frequency, which characterizes the response speed of the controller to track the reference signal.

4. The anti-disturbance control method based on adaptive super-helical permanent magnet synchronous motor according to claim 1 is characterized in that: In step 3, the specific adaptive super-helical perturbation sliding mode observer is: in, and for and The observed value of and Yes m and the derivative of Z(t); T e is the electromagnetic torque; k(.) is the adaptive function given by claim 5; sign(.) is the sign function; It is the difference between the set speed and the actual speed.

5. The method for anti-disturbance control of an adaptive super-helical permanent magnet synchronous motor according to claim 1, characterized in that: In step 3, the adaptive function is specifically expressed as: Where Δ represents the scaling factor (Δ>0).

6. The anti-disturbance control method based on adaptive super-helical permanent magnet synchronous motor according to claim 1 is characterized in that: In step 3, the non-singular fast terminal sliding mode controller obtains the expected value of the q-axis component of the motor stator current according to the following formula:

7. The anti-disturbance control method based on adaptive super-helical permanent magnet synchronous motor according to claim 1 is characterized in that: In step 4, the Clark transformation and IPark transformation matrices are specifically: Among them, θ e is the motor electrical angle.

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