CN104601071B - Permagnetic synchronous motor electric current loop System with Sliding Mode Controller based on disturbance observer - Google Patents

Abstract

The present invention relates to a kind of permagnetic synchronous motor electric current loop sliding-mode control based on disturbance observer, by building a sliding mode controller for multiple-input and multiple-output, using the relation that there is coupling between multi input amount, realize the decoupling tracing control of electric current loop, make current control inner ring only one of which controller, i.e. sliding mode controller.Consider simultaneously when external interference and system parameter variations, the robustness of Sliding mode variable structure control will weaken, therefore in order to further improve the robustness of system, a disturbance observer is added in control strategy, for the Uncertainty that online Prediction system is caused due to Parameters variation and external interference, the error compensation of system power is realized in compensation to sliding mode controller, electric current precise control is ensure that, permagnetic synchronous motor speed regulation performance is improve.The sliding mode controller based on disturbance observer for designing herein can make the permagnetic synchronous motor have more preferable robustness and an antijamming capability while quick tracking response is kept, and system architecture is simple, and stability is high, in can be applied to engineering practice.

Description

Permanent magnet synchronous motor current loop sliding mode control system based on disturbance observer

Technical Field

The invention relates to the field of motor control, in particular to a permanent magnet synchronous motor current loop sliding mode control system based on a disturbance observer and a control method thereof.

Background

The permanent magnet synchronous motor is a novel motor developed in recent years, and has the advantages of small rotor rotational inertia, high efficiency, large power density and high reliability, so that the permanent magnet synchronous motor is very suitable for being applied to a high-performance servo system, for example, in occasions such as a numerical control machine tool, and the permanent magnet synchronous motor is gradually replacing a direct current motor and an induction motor. Meanwhile, the permanent magnet synchronous motor does not need an exciting winding, so that the size is obviously reduced, the weight is lightened, the loss is reduced, the heating of the motor is avoided, and the efficiency and the power factor are improved, therefore, the permanent magnet synchronous motor can be more and more widely applied in the future.

The control method of the sliding mode variable structure is suitable for a nonlinear system with uncertain parameters. The control quantity is continuously switched through a control strategy, namely the structure of the system is continuously changed, and the system is purposefully forced to enter a preset sliding mode surface to slide. After the system enters the sliding mode state, the stability and the dynamic quality of the system only depend on the sliding mode surface and the parameters of the sliding mode surface. The sliding mode can be designed and is irrelevant to system parameter change and external disturbance, so that the robustness is strong and the reliability is high. Therefore, in recent years, the control method of the sliding mode variable structure is more and more emphasized by the control boundary. However, the robustness of the sliding mode variable structure control method is also limited, and when external interference and system parameter change are large, the robustness of the sliding mode variable structure control is weakened, and the system parameters and the external interference cannot be inhibited, so that in order to further improve the robustness of the system, many scholars introduce disturbance observers, estimate the uncertain quantities by designing the disturbance observers, compensate errors of the system, and improve the system performance and the adaptivity and robustness of the system.

Disclosure of Invention

The invention aims to provide a permanent magnet synchronous motor current loop sliding mode control method based on a disturbance observer, so that a system has good tracking performance and good robustness and anti-interference capability.

In order to achieve the purpose, the technical scheme of the invention is a permanent magnet synchronous motor current loop sliding mode control system based on a disturbance observer, which comprises a main circuit and a control circuit; the main circuit comprises an alternating current power supply which is connected with a three-phase inverter for supplying power for the operation of the permanent magnet synchronous motor through a rectifier; the control circuit comprises a current control inner ring, a speed control outer ring and a power circuit for supplying power to the control circuit, wherein a sliding mode controller for controlling the permanent magnet stepping motor and a disturbance observer for realizing the connection of the permanent magnet synchronous motor and the sliding mode controller are arranged in the current control inner ring; and the sliding mode controller is connected with the three-phase inverter through an SVPWM module.

Further, the power supply circuit comprises a 1.8V direct current power supply, a 3.3V direct current power supply, a 5V direct current power supply and a 15V direct current power supply.

Further, the speed control outer ring comprises a speed controller, and an output end of the speed controller is connected with an input end of the sliding mode controller.

And furthermore, the sliding mode controller also comprises a current sensor for detecting the current of each phase of stator of the permanent magnet stepping motor, and the output end of the current sensor is connected with the input end of the sliding mode controller.

The control method of the permanent magnet synchronous motor current loop sliding mode control system based on the disturbance observer comprises the following steps:

step S1: setting sliding mode parameters of a sliding mode controller, and acquiring a sliding mode surface equation;

step S2: obtaining a control law of the sliding mode controller;

step S3: designing a disturbance observer, acquiring a state space equation of the disturbance observer, and acquiring the uncertain quantity of the system according to the disturbance observer;

step S4: obtaining a control law of a sliding mode controller based on a disturbance observer;

step S5: and carrying out SVPWM modulation to obtain an actual driving signal of the permanent magnet stepping motor.

Further, in the above-mentioned case,

in step S1, according to the known pm synchronous machine voltage equation:

wherein v is_d，v_qAre respectively d-q axisStator voltage in coordinate system, i_d，i_qStator currents under a d-q axis coordinate system are respectively; r₀For each phase of stator resistance, L, of a PMSM₀For each phase of stator inductance, phi, of a permanent magnet synchronous machine₀Is the flux linkage of the permanent magnet synchronous motor, w is the angular velocity of the permanent magnet synchronous motor, n_pThe number of pole pairs of the permanent magnet synchronous motor is shown; by error signals e of stator currents_qAnd e_dFor the sliding mode parameters of the sliding mode controller, e_qAnd e_dForm parameter vector e ═ e_qe_d]^TAnd obtaining a sliding mode surface equation as follows: s ═ e + C ═ edt, where

Further, in the step S2, according to the sliding mode surface equation obtained in the step 1, an approach law is selected asWherein K is a diagonal matrix and sgn (S) is a column vector, i.e.The control law of the sliding mode controller is obtained as follows:

further, the step S3 further includes the following steps:

step S31: when the parameters R, L and phi of the permanent magnet synchronous motor change, the voltage equation after the parameters of the permanent magnet synchronous motor change is obtained as follows:

the uncertainty of a permanent magnet synchronous motor is defined as:

step S32: simplifying the voltage equation of the permanent magnet synchronous motor after the parameter change by the uncertain quantity in the step S31 to obtain:

wherein, the delta R, the delta L and the delta phi are respectively the variable quantities of the parameters R, L and phi of the permanent magnet synchronous motor,_dand_qthe remaining uncertainty of the current loop of the permanent magnet stepping motor;

step S33: setting the derivative of the uncertainty amount to zero, i.e.The indefinite amount is set to ═ 2_{q d}]^TAs the state variable, the estimated value is defined asAnd combining a voltage equation after the parameter of the permanent magnet synchronous motor is changed to obtain a state space equation of the disturbance observer as follows:

wherein x ═ i_qi_d]^T，v＝[v_qv_d]^T，

Step S34: according to the state space equation of the disturbance observer in the step S33, the uncertainty of the system is obtained as follows:

namely the response of the open-loop disturbance observer;

step S35: according to the response of the open-loop disturbance observer in step S34, the dynamic response of the closed-loop disturbance observer is obtained as follows:

wherein, the matrixes lambda and L are gain matrixes of the disturbance observer, and T is determined by the matrix L.

Further, the uncertainty obtained by the disturbance observer in step S34 is compensated to the output of the sliding mode controller, and the control law of the sliding mode controller based on the disturbance observer is obtained as follows:

compared with the prior art, the invention has the following beneficial effects:

(1) according to the invention, the disturbance observer is added in the current control inner ring, so that the control of the current ring is not influenced by the parameter change and external disturbance of the permanent magnet stepping motor, and the tracking precision and the anti-interference performance of the current ring of the permanent magnet stepping motor are improved;

(2) compared with the traditional sliding mode control, the sliding mode controller based on the disturbance observer can realize decoupling control of a current loop, reduce fluctuation of a system in a steady state and improve steady-state precision;

(3) compared with the traditional disturbance observer, the disturbance observer is a second-order linear observer, and has high response speed and simple structure;

(4) the system provided by the invention has the advantages of simple structure and high stability, and can be applied to engineering practice.

Drawings

FIG. 1 is a block diagram of a multivariable sliding mode control system of the present invention.

FIG. 2 is a block diagram of the structural design of the disturbance observer of the present invention.

Detailed Description

The technical scheme of the invention is specifically explained below with reference to the accompanying drawings.

As shown in fig. 1 to 2, a current loop sliding mode control system of a permanent magnet synchronous motor based on a disturbance observer according to an embodiment of the present invention includes a main circuit and a control circuit; the main circuit comprises an alternating current power supply which is connected with a three-phase inverter for supplying power for the operation of the permanent magnet synchronous motor through a rectifier; the control circuit comprises a current control inner ring, a speed control outer ring and a power circuit for supplying power to the control circuit, wherein a sliding mode controller for controlling the permanent magnet stepping motor and a disturbance observer for realizing the connection of the permanent magnet synchronous motor and the sliding mode controller are arranged in the current control inner ring; and the sliding mode controller is connected with the three-phase inverter through an SVPWM module.

In the invention, the disturbance observer is added in the current control inner loop, so that the current loop control is not influenced by the parameter change of the permanent magnet stepping motor and external disturbance, and the tracking precision and the anti-interference performance of the current loop of the permanent magnet stepping motor are improved; compared with the traditional sliding mode control, the sliding mode controller is a multivariable sliding mode controller, so that the decoupling control of a current loop can be realized, the fluctuation of the system in a steady state can be reduced, and the steady-state precision is improved; compared with the traditional disturbance observer, the disturbance observer is a second-order linear observer, and has high response speed and simple structure; the system provided by the invention has the advantages of simple structure and high stability, and can be applied to engineering practice.

In the present embodiment, the power supply circuit includes a 1.8V dc power supply, a 3.3V dc power supply, a 5V dc power supply, and a 15V dc power supply.

In this embodiment, the speed control outer loop comprises a speed controller, and an output end of the speed controller is connected with an input end of the sliding mode controller.

In this embodiment, the sliding mode controller further comprises a current sensor for detecting the stator current of each phase of the permanent magnet stepping motor, and the output end of the current sensor is connected with the input end of the sliding mode controller.

The control method of the permanent magnet synchronous motor current loop sliding mode control system based on the disturbance observer comprises the following steps:

step S1: setting sliding mode parameters of a sliding mode controller, and acquiring a sliding mode surface equation;

step S2: obtaining a control law of the sliding mode controller;

step S3: designing a disturbance observer, acquiring a state space equation of the disturbance observer, and acquiring the uncertain quantity of the system according to the disturbance observer;

step S4: obtaining a control law of a sliding mode controller based on a disturbance observer;

step S5: and carrying out SVPWM modulation to obtain an actual driving signal of the permanent magnet stepping motor.

In the present embodiment, in the step S1, according to the known voltage equation of the permanent magnet synchronous motor:

wherein v is_d，v_qStator voltages i in d-q axis coordinate system, respectively_d，i_qStator currents under a d-q axis coordinate system are respectively; r₀For each phase of stator resistance, L, of a PMSM₀For each phase of stator inductance, phi, of a permanent magnet synchronous machine₀Is the flux linkage of the permanent magnet synchronous motor, w is the angular velocity of the permanent magnet synchronous motor, n_pThe number of pole pairs of the permanent magnet synchronous motor is shown; by error signals e of stator currents_qAnd e_dFor the sliding mode parameters of the sliding mode controller, e_qAnd e_dForm parameter vector e ═ e_qe_d]^TAnd obtaining a sliding mode surface equation as follows: s ═ e + C ═ edt, where

In this embodiment, in the step S2, according to the sliding mode surface equation obtained in the step 1, an approach law is selected asWherein K is a diagonal matrix and sgn (S) is a column vector, i.e.The control law of the sliding mode controller is obtained as follows:

in this embodiment, the step S3 further includes the following steps:

step S31: when the parameters R, L and phi of the permanent magnet synchronous motor change, the voltage equation after the parameters of the permanent magnet synchronous motor change is obtained as follows:

the uncertainty of a permanent magnet synchronous motor is defined as:

step S32: simplifying the voltage equation of the permanent magnet synchronous motor after the parameter change by the uncertain quantity in the step S31 to obtain:

wherein, the delta R, the delta L and the delta phi are respectively the variable quantities of the parameters R, L and phi of the permanent magnet synchronous motor,_dand_qthe remaining uncertainty of the current loop of the permanent magnet stepping motor;

step S33: setting the derivative of the uncertainty amount to zero, i.e.The indefinite amount is set to ═ 2_{q d}]^TAs the state variable, the estimated value is defined asAnd combining a voltage equation after the parameter of the permanent magnet synchronous motor is changed to obtain a state space equation of the disturbance observer as follows:

wherein x ═ i_qi_d]^T，v＝[v_qv_d]^T，

Step S34: according to the state space equation of the disturbance observer in the step S33, the uncertainty of the system is obtained as follows:

namely the response of the open-loop disturbance observer;

step S35: according to the response of the open-loop disturbance observer in step S34, the dynamic response of the closed-loop disturbance observer is obtained as follows:

wherein, the matrixes lambda and L are gain matrixes of the disturbance observer, and T is determined by the matrix L. The disturbance observer is a second-order disturbance observer, and is high in response speed and simple in structure.

In this embodiment, the uncertainty obtained by the disturbance observer in step S34 is compensated to the output of the sliding mode controller, and the control law of the sliding mode controller based on the disturbance observer is obtained as follows:

from the above, the invention is designed by adopting a mature vector control technology, and firstly, the stator three-phase current i of the permanent magnet synchronous linear motor is detected by using a current sensor_A、i_B、i_CAnd the three-phase current of the stator is subjected to Clark conversion to obtain the current i under a two-phase static coordinate system_αAnd i_βAnd then the current i under the two-phase static coordinate system is converted by Park_αAnd i_βConversion into a current i in a two-phase rotating coordinate system_dAnd i_q，i_dAnd i_qI.e. the feedback current of the current loop. In the vector control technology of the permanent magnet synchronous motor, in order to improve the power factor of the motor and reduce the torque ripple, the d-axis current is set as i_d ^*0 and q-axis current setpoint is the output i of the speed control outer loop PI controller_q ^*。

In summary, the disturbance observer-based current loop sliding mode control system of the permanent magnet synchronous motor and the control method thereof provided by the invention enable the control system to have good tracking performance and good robustness and anti-interference capability.

The above are preferred embodiments of the present invention, and all changes made according to the technical scheme of the present invention that produce functional effects do not exceed the scope of the technical scheme of the present invention belong to the protection scope of the present invention.

Claims (5)

1. A permanent magnet synchronous motor current loop sliding mode control system based on a disturbance observer is characterized in that: comprises a main circuit and a control circuit; the main circuit comprises an alternating current power supply which is connected with a three-phase inverter for supplying power for the operation of the permanent magnet synchronous motor through a rectifier; the control circuit comprises a current control inner ring, a speed control outer ring and a power circuit for supplying power to the control circuit, wherein a sliding mode controller for controlling the permanent magnet synchronous motor and a disturbance observer for realizing the connection of the permanent magnet synchronous motor and the sliding mode controller are arranged in the current control inner ring; the sliding mode controller is connected with the three-phase inverter through an SVPWM module; the control method of the permanent magnet synchronous motor current loop sliding mode control system based on the disturbance observer comprises the following steps:

step S1: setting sliding mode parameters of a sliding mode controller, and acquiring a sliding mode surface equation;

step S2: obtaining a control law of the sliding mode controller;

step S3: designing a disturbance observer, acquiring a state space equation of the disturbance observer, and acquiring the uncertain quantity of the system according to the disturbance observer;

step S4: obtaining a control law of a sliding mode controller based on a disturbance observer;

step S5: carrying out SVPWM (space vector pulse width modulation) to obtain an actual driving signal of the permanent magnet synchronous motor;

in step S1, according to the known pm synchronous machine voltage equation:

$\left\{\begin{array}{c}{v}_q=R_0{i}_q+L_0\frac{{\mathrm{di}}_q}{dt}+n_p{L}_{0}w{i}_d+n_p{\mathrm{\φ}}_{0}w\\ v_d=R_0{i}_d+L_0\frac{{\mathrm{di}}_d}{dt}-n_p{L}_{0}w{i}_q\end{array}\right.;$

wherein v is_d，v_qStator voltages i in d-q axis coordinate system, respectively_d，i_qStator currents under a d-q axis coordinate system are respectively; r₀For each phase of stator resistance, L, of a PMSM₀For each phase of stator inductance, phi, of a permanent magnet synchronous machine₀Is the flux linkage of the permanent magnet synchronous motor, w is the angular velocity of the permanent magnet synchronous motor, n_pThe number of pole pairs of the permanent magnet synchronous motor is shown; by error signals e of stator currents_qAnd e_dFor the sliding mode parameters of the sliding mode controller, e_qAnd e_dForm parameter vector e ═ e_qe_d]^TTo obtain a slip form surfaceThe process is as follows: s ═ e + C ═ edt, where the matrix of coefficients of the integral term

In step S2, according to the sliding mode surface equation obtained in step 1, an approach law is selected asWherein K is a diagonal matrix and sgn (S) is a column vector, i.e.The control law of the sliding mode controller is obtained as follows:

$\left[\begin{array}{c}{u}_q\\ u_d\end{array}\right]=\left[\begin{array}{c}{L}_o{\stackrel{\·}{i}}_q^{*}+R_o{i}_q+n_p{L}_{o}w{i}_d+n_p{\mathrm{\φ}}_{o}w\\ L_o{\stackrel{\·}{i}}_d^{*}+R_o{i}_d-n_p{L}_{o}w{i}_q\end{array}\right]+L_o\mathrm{\ϵ}sgn\left(S\right)+L_{o}KS+L_{o}Ce;$

wherein u is_q、u_dQ-axis voltage and d-axis voltage respectively; i.e. i_q ^*And i_dReference input currents of q and d axes are respectively;

the step S3 further includes the steps of:

step S31: when the resistance, inductance and flux linkage parameters R, L and phi of the permanent magnet synchronous motor change, the voltage equation after the parameter change of the permanent magnet synchronous motor is obtained as follows:

$\left\{\begin{array}{c}{v}_q=(R_o+\mathrm{\Δ}R)i_q+(L_o+\mathrm{\Δ}L)\frac{{\mathrm{di}}_q}{dt}+n_p(L_o+\mathrm{\Δ}L)w{i}_d+n_p({\mathrm{\φ}}_o+\mathrm{\Δ}\mathrm{\φ})w+{\mathrm{\ϵ}}_q\\ v_d=(R_o+\mathrm{\Δ}R)i_d+(L_o+\mathrm{\Δ}L)\frac{{\mathrm{di}}_d}{dt}-n_p(L_o+\mathrm{\Δ}L)w{i}_q+{\mathrm{\ϵ}}_d\end{array}\right.;$

wherein,_dand_qthe remaining uncertainty of the current loop of the permanent magnet synchronous motor;

the uncertainty of a permanent magnet synchronous motor is defined as:

wherein, the delta R, the delta L and the delta phi are respectively the variable quantities of the parameters R, L and phi of the permanent magnet synchronous motor;

step S32: simplifying the voltage equation of the permanent magnet synchronous motor after the parameter change by the uncertain quantity in the step S31 to obtain:

$\left\{\begin{array}{c}{v}_q=R_o{i}_q+L_o\frac{{\mathrm{di}}_q}{dt}+n_p{L}_o{\mathrm{wi}}_d+n_p{\mathrm{\φ}}_{o}w+{\mathrm{\δ}}_q\\ v_d=R_o{i}_d+L_o\frac{{\mathrm{di}}_d}{dt}-n_p{L}_o{\mathrm{wi}}_q+{\mathrm{\δ}}_d\end{array}\right.;$

wherein,_qand_dis the uncertainty of q and d axes;

step S33: setting the derivative of the uncertainty amount to zero, i.e.The indefinite amount is set to ═ 2_{q d}]^TAs the state variable, the estimated value is defined asAnd combining a voltage equation after the parameter of the permanent magnet synchronous motor is changed to obtain a state space equation of the disturbance observer as follows:

$\left(\begin{array}{c}\stackrel{\·}{x}\\ \stackrel{\·}{\mathrm{\δ}}\end{array}\right)=\left(\begin{array}{cc}{A}_{11}& A_{12}\\ A_{21}& A_{22}\end{array}\right)\left(\begin{array}{c}x\\ \mathrm{\δ}\end{array}\right)+\left(\begin{array}{c}{B}_1\\ B_2\end{array}\right)v+\left(\begin{array}{c}{G}_1\\ G_2\end{array}\right)$

wherein x ═ i_qi_d]^T，v＝[v_qv_d]^T，

$A_{11}=\left[\begin{array}{cc}-\frac{R_o}{L_o}& -n_{p}w\\ n_{p}w& -\frac{R_o}{L_o}\end{array}\right],A_{12}=\left[\begin{array}{cc}-\frac{1}{L_o}& 0\\ 0& -\frac{1}{L_o}\end{array}\right],B_1=\left[\begin{array}{cc}\frac{1}{L_o}& 0\\ 0& \frac{1}{L_o}\end{array}\right];$

Step S34: according to the state space equation of the disturbance observer in the step S33, the uncertainty of the system is obtained as follows:

namely the response of the open-loop disturbance observer;

step S35: according to the response of the open-loop disturbance observer in step S34, the dynamic response of the closed-loop disturbance observer is obtained as follows:

wherein, the matrixes lambda and L are gain matrixes of the disturbance observer, and T is determined by the matrix L.

2. The permanent magnet synchronous motor current loop sliding mode control system based on the disturbance observer is characterized in that: the power supply circuit comprises a 1.8V direct-current power supply, a 3.3V direct-current power supply, a 5V direct-current power supply and a 15V direct-current power supply.

3. The permanent magnet synchronous motor current loop sliding mode control system based on the disturbance observer is characterized in that: the speed control outer ring comprises a speed controller, and the output end of the speed controller is connected with the input end of the sliding mode controller.

4. The permanent magnet synchronous motor current loop sliding mode control system based on the disturbance observer is characterized in that: the sliding mode controller also comprises a current sensor for detecting the current of each phase of stator of the permanent magnet synchronous motor, and the output end of the current sensor is connected with the input end of the sliding mode controller.

5. The permanent magnet synchronous motor current loop sliding mode control system based on the disturbance observer is characterized in that: and (4) compensating the uncertain quantity obtained by the disturbance observer in the step (S34) to the output of the sliding mode controller to obtain the control law of the sliding mode controller based on the disturbance observer as follows:

$U=\left[\begin{array}{c}{u}_q\\ u_d\end{array}\right]=\left[\begin{array}{c}{L}_o{\stackrel{\·}{i}}_q^{*}+R_o{i}_q+n_p{L}_{o}w{i}_d+n_p{\mathrm{\φ}}_{o}w\\ L_o{\stackrel{\·}{i}}_d^{*}+R_o{i}_d-n_p{L}_{o}w{i}_q\end{array}\right]+\widehat{\mathrm{\δ}}+L_o\mathrm{\ϵ}sgn\left(S\right)+L_{o}KS+L_{o}Ce.$