A control barrier function-based permanent magnet synchronous motor current-constrained speed regulation method

Abstract

The application discloses a kind of permanent magnet synchronous motor current restriction speed regulation methods based on control barrier function, belong to motor control field, this method estimates the matching and non-matching multi-source disturbance in system by disturbance observer, then based on disturbance estimation information, construct control barrier function as motor current restriction, construct control Lyapunov function as constraint to guarantee the stability of motor closed-loop speed regulation system, to construct current restriction composite controller, and as current restriction controller under non-series control structure, to realize permanent magnet synchronous motor servo system under the speed control of disturbance influence;The application uses the composite control method based on disturbance observer to eliminate the influence of multi-source disturbance on speed tracking and current restriction, while realizing high-precision speed tracking, guarantee strict current restriction.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of motor control, and more particularly, to a current-constrained speed regulation method for permanent magnet synchronous motor based on control barrier function. BACKGROUND

[0002] Permanent magnet synchronous motor has the characteristics of high air-gap flux density, small torque ripple, high efficiency and simple structure, and is in a dominant position in small and medium power AC speed regulation systems such as industrial robot control, numerical control machine tool, aerospace and military weapon following system. With the development of power electronics technology and modern control theory, more and more scholars have started to study the speed regulation control problem of permanent magnet synchronous motor under non-series structure. Compared with the traditional series control structure, the non-series structure which combines the speed loop and the current loop into a second-order system has many advantages such as simple parameter adjustment, direct control quantity and large control bandwidth.

[0003] Although the non-series speed regulation of permanent magnet synchronous motor has the above advantages in its control structure, it also brings two challenges to the control. First, in the series structure, the control reference value of q-axis current is determined by the output of the speed loop and is limited by the saturation function. However, in the non-series speed regulation structure, the q-axis current becomes an intermediate state, so it cannot be limited in the same way. Excessive current may cause damage to electronic devices and motors in the circuit. Second, there are multiple sources of fast-changing disturbances in the permanent magnet synchronous motor system, such as cogging torque, flux harmonic, parameter uncertainty, unmodeled dynamics and unknown load torque. These disturbances cannot be directly compensated because they are not in the same channel as the control input, resulting in an undesirable speed regulation effect.

[0004] To address these two challenges, scholars both domestically and internationally have conducted extensive research. The paper "S. Zhou, S. Sui, and S. Tong. Adaptive neural networks optimal control of permanent magnet synchronous motor system with state constraints. Neurocomputing [J], 2022, 504:132-140" uses the backstepping design principle to introduce a barrier Lyapunov function to constrain the state at each step of the backstepping design. However, backstepping requires continuous differentiation of intermediate virtual control variables during the iterative controller solution. This complicates the computational process and increases the amount of computation, making it difficult to achieve ideal control results. The paper “J.Liu, J.Yang, S.Li, and X.Wang. Single-loop robust model predictive speed regulation of PMSM based on exogenous signal preview. IEEE Transactions on Industrial Electronics[J], 2023, 70(12): 12719-12729” adopts a model predictive control method and adds information about the state to be constrained when solving the controller, thereby obtaining a control input that satisfies the constraints. Unfortunately, this control method may face the challenge of conflicting requirements for fast system response and the heavy computational burden brought by online optimization. Therefore, it is difficult to implement in some application environments that require real-time computing. The paper “T.Guo, Z.Sun, X.Wang, S.Li, and K.Zhang. A simple current-constrained controller for permanent-magnet synchronous motor. IEEE Transactions on Industrial Informatics[J], 2019, 15(3): 1486-1495” proposes a current constraint control scheme that takes into account both overcurrent protection and speed dynamic response. That is, based on the traditional proportional differential feedback controller, the barrier function design idea is introduced. This scheme adds a current constraint penalty term to the feedback controller to constrain the current, thereby achieving overcurrent protection. However, when the q-axis current is closer to the limit value, the penalty gain becomes larger, resulting in a larger control input, which is difficult to implement in actual application. In addition, this scheme uses a nonlinear penalty term, which only applies to the current equivalent value of the load torque. This is true when the current limit value c is less than the current limit value c. Summary of the Invention

[0005] In response to the above-mentioned defects or improvement needs of the prior art, the present invention provides a permanent magnet synchronous motor current constraint speed control method based on a control barrier function for a permanent magnet synchronous motor system under a non-cascade control structure, which can eliminate the influence of multi-source fast-changing interference on speed tracking and current constraint, and ensure strict current constraint while achieving high-precision speed tracking.

[0006] To achieve the above objectives, according to a first aspect of the present invention, a method for current-constrained speed regulation of a permanent magnet synchronous motor based on a control barrier function is provided, comprising:

[0007] S1, the desired mechanical angular velocity ω of the motor rotor r , motor mechanical angular velocity ω and motor q-axis current i q As the state quantity, a control model of the permanent magnet synchronous motor servo system is established;

[0008] S2, using interference observer to estimate the system matching interference d q and mismatch interference d ω ;

[0009] S3, according to the control model and d q The estimated value ζ2 is used to construct a control barrier function as the motor current constraint; according to the control model and d ω The estimated value z2 is used to construct the control Lyapunov function as a constraint to ensure the stability of the system, so as to establish the current constraint composite controller;

[0010] S4, controlling the permanent magnet synchronous motor servo system based on the current constraint composite controller;

[0011] Wherein, the current constraint composite controller is:

[0012]

[0013] u∈u max

[0014] in, is the control model of the system, x1=ω r -ω, u=u q -R s i q -ω e L s i d -ω e ψ f , K m =1.5n p ψ f, n p is the number of pole pairs, ψ f is the permanent magnet flux linkage, J is the moment of inertia, B is the viscous friction coefficient, u q is the stator winding q-axis voltage, R s is the stator resistance, i d is the motor d-axis stator current, ω e is the rotor electrical angular velocity, L s is the stator inductance, and are control barrier functions; is a control Lyapunov function, δ is a relaxation factor, β c is a control barrier function gain, and are the upper and lower bounds of the current constraint respectively, c is the current clipping value, η, φ and β are positive numbers; ε2 is an estimation error term of d q , is a Lyapunov function, is a positive definite matrix, α is a control Lyapunov function gain, is a positive number, u max is the maximum value of the control input u.

[0015] According to a second aspect of the present application, there is provided an electronic device, comprising: a computer readable storage medium and a processor;

[0016] The computer readable storage medium is configured to store executable instructions;

[0017] The processor is configured to read the executable instructions stored in the computer readable storage medium, and execute the method according to the first aspect.

[0018] According to a third aspect of the present application, there is provided a computer readable storage medium, the computer readable storage medium storing computer instructions, the computer instructions being configured to cause a processor to execute the method according to the first aspect.

[0019] In general, the above technical solutions conceived by the present application can achieve the following beneficial effects compared with the prior art:

[0020] 1. The method provided by the present invention estimates the matched and unmatched multi-source interference in the system through an interference observer, and then constructs a control obstacle function as a motor current constraint based on the interference estimation information, and constructs a control Lyapunov function as a constraint to ensure the stability of the motor speed regulation closed-loop system, thereby ensuring high-precision speed regulation. Based on the above constraints, a current constraint composite controller is constructed and used as a current constraint controller under a non-cascade control structure to achieve speed control of a permanent magnet synchronous motor servo system under the influence of disturbances; the present invention utilizes a composite control method based on an interference observer to eliminate the influence of multi-source interference on speed tracking and current constraint, while achieving high-precision speed tracking and ensuring strict current constraint.

[0021] 2. The existing method of realizing current constraint control through nonlinear penalty term only applies the current equivalent value of the load torque. Compared with this method, the method provided by the present invention achieves strict current constraint by controlling the barrier function technology. Specifically, the control input set for achieving the current constraint obtained by controlling the barrier function is:

[0022]

[0023] The control input set to achieve the stability of the closed-loop system by controlling the Lyapunov function is: The final calculated composite control input is the intersection of the two u∈{K u1 ∩K u2 Therefore, no matter whether the current equivalent value of the applied load torque is greater than the motor current constraint value, the present invention can ensure strict current constraint. That is, the present invention can not only ensure The current constraint is less than the current limit value c, and when the applied load torque makes , the present invention can still ensure current constraint. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A flowchart of a permanent magnet synchronous motor current constraint speed regulation method based on a control barrier function provided in an embodiment of the present invention.

[0025] Figure 2 This is the block diagram of the permanent magnet synchronous motor servo system based on vector control; DETAILED DESCRIPTION

[0026] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0027] The embodiment of the present invention provides a permanent magnet synchronous motor current constraint speed regulation method based on the control barrier function, such as Figure 1 Shown, including:

[0028] S1, the desired mechanical angular velocity ω of the motor rotor r , motor mechanical angular velocity ω and motor q-axis current i q As the state quantity, a control model of the permanent magnet synchronous motor servo system is established.

[0029] Specifically, according to the mathematical model of the permanent magnet synchronous motor, the desired mechanical angular velocity ω of the motor rotor is r , motor mechanical angular velocity ω, motor q-axis current i q As the state quantity, a control model of the permanent magnet synchronous motor servo system is established.

[0030] The mathematical model of the permanent magnet synchronous motor servo system is:

[0031]

[0032] Among them, u d and u q They are the stator winding d and q axis voltages, i d and i q is the stator current of d and q axes, L s is the stator inductance, R s is the stator resistance, ω e is the electrical angular velocity of the rotor, ψ f is the permanent magnet flux, J is the moment of inertia, B is the viscous friction coefficient; T L is the load torque; K m =1.5n p ψ f ;n p is the extreme logarithm.

[0033] The control model of the system is:

[0034]

[0035] in, x1=ω r -ω, u=u q -Rs i q -ω e L s i d -ω e ψ f , d q is the matched disturbance in the system, d ω is the unmatched disturbance in the system.

[0036] S2, the matched disturbance d q and the unmatched disturbance d ω in the system are estimated respectively by using a disturbance observer.

[0037] It can be understood that, in step S2, the disturbance observer used for estimating the matched disturbance d q and the unmatched disturbance d ω may adopt any existing disturbance observer, for example, a generalized proportional integral observer GPIO, an extended state observer ESO, a disturbance observer DOB, etc. The embodiment of the present application does not make a unique limitation on this.

[0038] As an example, preferably, the generalized proportional integral observer GPIO is used as the disturbance observer to estimate the matched disturbance d q in the system.

[0039]

[0040] wherein ζ1 is the estimated value of x2, ζ2...ζ n+1 are respectively the estimated values of the matched disturbance d q and the derivative thereof, and p1...p n+1 are the observer gains of the GPIO.

[0041] The generalized proportional integral observer GPIO is used as the disturbance observer to estimate the unmatched disturbance d ω in the system.

[0042]

[0043] wherein z1 is the estimated value of x1, z2...z n+1 are respectively the estimated values of the unmatched disturbance d ω and the derivative thereof, and l1...l n+1 are the observer gains of the GPIO.

[0044] S3, a control barrier function is constructed as a motor current constraint according to the control model and the estimated value ζ2 of d q , and a control Lyapunov function is constructed as a constraint to ensure the stability of the system according to the control model and the estimated value z2 of d ω , so as to establish a current constraint composite controller.

[0045] Specifically, based on the matching interference d q and mismatch interference d ω The estimated information of is used to construct a current constraint composite controller by controlling the Lyapunov function and controlling the barrier function. The quadratic programming method is used to solve it and the optimal control input u is obtained.

[0046] The current constraint composite controller is:

[0047]

[0048] u∈u max

[0049] in, and is the control obstacle function, i.e., the motor current constraint; is the control Lyapunov function, which is used as a constraint to ensure the stability of the system; δ is the relaxation factor; β c is the control barrier function gain, β c The larger it is, the stronger the current restraint capability is, and vice versa; and are the upper and lower bounds of the current constraint, c is the current limit value; η, φ and β are positive numbers (the specific values ​​can be set according to the actual situation, for example, Figure 1 As shown, η and φ can be taken as 1 / 2); ε2 is the matching interference d q The estimated error term of ; is the Lyapunov function, is a positive definite matrix; α controls the Lyapunov function gain. The larger α is, the faster the closed-loop system converges, and vice versa. is a positive number; u max is the maximum value of the control input.

[0050] S4, controlling the permanent magnet synchronous motor servo system based on the current constraint composite controller.

[0051] Specifically, solve the current constraint composite controller established by S3 to obtain the optimal control input u, and then use u q =u+R s i q +ω e L s i d +ω e ψ f Get the actual optimal control input u d , to control the permanent magnet synchronous motor servo system.

[0052] like Figure 2As shown, S4 includes:

[0053] S4.1, setting as the setting signal of the d-axis current controller; the collected motor current signal i a , b Carry out Clarke transformation and Park transformation operation to obtain the current value i d and i q in the dq coordinate system. d , q As the feedback signal of the d-axis current controller (i.e. PI controller) and the q-axis current controller (i.e. current constraint compound controller), through the control action of the d-axis current controller and the q-axis current controller, the output u d and u q of the dq-axis current controller are obtained.

[0054] S4.2, Park inverse transformation is performed on the output u d and u q of the dq-axis current controller to obtain the reference value u α and u β of the stator phase voltage in the αβ coordinate system.

[0055] S4.3, according to u α and u β , the PWM control signal is generated by using the space vector pulse width modulation technology.

[0056] S4.4, the controllable switching device IGBT is controlled by the PWM control signal, and the required three-phase alternating current is invertered to drive the motor to operate, and the actual speed of the motor is obtained.

[0057] Preferably, in the permanent magnet synchronous motor servo system, the optical encoder is used to collect the speed signal of the PMSM servo motor, and the Hall current sensor is used to collect the current signal of the motor.

[0058] An electronic device is provided, and the electronic device comprises a computer readable storage medium and a processor.

[0059] The computer readable storage medium is used for storing executable instructions.

[0060] The processor is used for reading the executable instructions stored in the computer readable storage medium, and executing the method according to any one of the above embodiments.

[0061] A computer readable storage medium is provided, and the computer readable storage medium stores computer instructions, and the computer instructions are used for making a processor execute the method according to any one of the above embodiments.

[0062] Those skilled in the art can easily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for current-constrained speed regulation of a permanent magnet synchronous motor based on a control barrier function, characterized in that: include: S1, the desired mechanical angular velocity of the motor rotor , motor mechanical angular velocity and motor Shaft current As the state quantity, a control model of the permanent magnet synchronous motor servo system is established; S2, using interference observer to estimate the matching interference of the system and mismatch interference ; S3, according to the control model and Estimated value of , construct a control obstacle function as the motor current constraint; according to the control model and Estimated value of , a control Lyapunov function is constructed as a constraint to ensure system stability in order to establish a current-constrained composite controller; S4, controlling the permanent magnet synchronous motor servo system based on the current constraint composite controller; Wherein, the current constraint composite controller is: in, is the control model of the system, , , , , , , , is the polar logarithm, is the permanent magnet flux linkage, J is the moment of inertia, B is the viscous friction coefficient, For stator winding q Shaft voltage, is the stator resistance, For motor d Shaft stator current, is the electrical angular velocity of the rotor, is the stator inductance, and is the control barrier function; To control the Lyapunov function, is the relaxation factor, is the control barrier function gain, and are the upper and lower bounds of the current constraint, c is the current limit value, , and is a positive number; yes The estimated error term, is the Lyapunov function, is a positive definite matrix, , , is the control Lyapunov function gain, is a positive number, is the control input The maximum value of .

2. The method according to claim 1, wherein Using Generalized Proportional Integral Observer (GPIO) as a Disturbance Observer to Estimate the Matching Disturbance of the System : in, yes The estimated value of Matched interference and its derivative estimates, is the observer gain of the GPIO.

3. The method according to claim 1 or 2, wherein: Using Generalized Proportional Integral Observer (GPIO) as Disturbance Observer to Estimate System Mismatched Disturbance : in, yes The estimated value of Non-matching interference and its derivative estimates, is the observer gain of the GPIO.

4. The method according to claim 1, wherein Step S4 includes: S4.1, Setting As d The set signal of the axis current controller; the collected motor current signal is subjected to Clarke transformation and Park transformation to obtain dq Current value in the coordinate system and , respectively and As d Axis current controller and q The feedback signal of the axis current controller is d Axis current controller and q The control effect of the axis current controller is obtained d, q Output of the axis current controller and ;in, d The axis current controller is a PI controller. q The axis current controller is a current constraint compound controller; S4.2, yes and Perform the Park inverse transform and get Reference value of stator phase voltage in coordinate system and ; S4.3, according to and Use space vector pulse width modulation technology to generate PWM control signal; S4.4, the controllable switching device IGBT is controlled by the PWM control signal to invert the required three-phase AC power to drive the motor to operate and obtain the actual motor speed.

5. The method according to claim 1, wherein A photoelectric encoder is used to collect the speed signal of the permanent magnet synchronous motor servo motor, and a Hall current sensor is used to collect the current signal of the motor.

6. An electronic device, characterized in that: include: Computer-readable storage medium and processor; The computer-readable storage medium is used to store executable instructions; The processor is configured to read the executable instructions stored in the computer-readable storage medium and execute the method according to any one of claims 1 to 5.

7. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to execute the method according to any one of claims 1 to 5.

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