A two-step flux linkage prediction robust control method and system for a permanent magnet motor system

Abstract

The application discloses a kind of permanent magnet motor system flux linkage two-step prediction robust control method and system, the method constructs the flux linkage composite prediction controller of flux linkage ring control model based on two-step prediction.Specifically: obtain the real-time state parameter of permanent magnet motor system;Observe the rotational speed ring disturbance and the flux linkage ring coupling disturbance;Rotational speed ring control utilizes motor speed and rotational speed ring disturbance to predict q-axis current instruction;Flux linkage ring control is predicted by flux linkage composite prediction controller using d,q-axis current instruction and flux linkage ring coupling disturbance The expected voltage vector of k+2 time;Further, after inverse Park transformation and modulation processing, finally converted into PWM pulse signal, to drive permanent magnet motor.The above technical solution effectively eliminates the influence of irreversible one beat delay in digital control system, improves the flux linkage and rotational speed control precision of permanent magnet motor system, significantly enhances the robustness of permanent magnet motor system to parameter uncertainty and external disturbance.

Description

Technical Field

[0001] This invention relates to the field of control technology for permanent magnet motors, and specifically to a two-step predictive robust control method and system for flux linkage in a permanent magnet motor system. Background Technology

[0002] High-performance speed regulation of permanent magnet motor systems relies heavily on the precise execution of digital control algorithms. Deadbeat predictive control, with its advantages of fast transient response and no need for complex parameter tuning, has great potential in the field of motor applications. However, in practical engineering applications, existing predictive control technologies inherently suffer from computational delay issues. From acquiring current and position signals and executing the predictive algorithm to setting the pulse width modulation (PWM) duty cycle, a fixed amount of physical time is required. This "one-beat delay" phenomenon causes the actual voltage vector applied by the controller to lag behind the real-time state of the motor. Without an effective multi-step prediction and delay compensation mechanism, this phase lag can cause severe current oscillations during high-bandwidth speed regulation, directly weakening the system's stability.

[0003] In addition, predictive control is extremely sensitive to the internal physical parameters of the motor. During actual motor operation, stator winding temperature rise leads to thermal drift of resistance, core magnetic circuit saturation causes nonlinear changes in inductance, and demagnetization under complex operating conditions leads to attenuation of permanent magnet flux linkage. When the nominal model used by the controller mismatches with the actual physical state of the motor, the expected voltage command calculated based on the ideal mathematical model will have inherent deviations, resulting in steady-state current tracking errors and torque ripple in the system.

[0004] It has been demonstrated that, under conditions of flux linkage parameter mismatch and rotor position detection error, the traditional two-step current prediction method will show a deviation between the current response value and its command value. Existing technologies cannot simultaneously achieve two-step delay compensation and disturbance suppression. Summary of the Invention

[0005] This invention aims to address the technical problem of significant deviations between the current response value and the command value in traditional two-step current prediction methods under conditions of flux linkage parameter mismatch and rotor position detection errors. This invention proposes a robust two-step flux linkage prediction control method and system for permanent magnet motor systems. Specifically, it constructs a flux linkage composite predictive controller based on a two-step prediction flux linkage loop control model to achieve prediction of the desired voltage vector at time k+2. Unlike traditional two-step current prediction methods that use current as an intermediate variable, the flux linkage composite predictive controller proposed in this application is based on the theoretical basis of achieving error-free tracking of the actual flux linkage value with respect to the given value at time k+2. It targets the more fundamental state variable (flux linkage) to achieve more precise and direct control of the motor's electromagnetic processes. Furthermore, the control technology of this invention incorporates total disturbance, which can actively suppress the adverse effects of uncertainties such as changes in motor parameters and permanent magnet demagnetization, thereby significantly improving the system's control accuracy, dynamic response capability, and long-term operational reliability.

[0006] Therefore, the present invention provides the following technical solution:

[0007] On the one hand, the present invention provides a two-step predictive robust control method for flux linkage in a permanent magnet motor system, which constructs a flux linkage composite predictive controller based on a two-step predictive flux linkage loop control model to achieve prediction of the desired voltage vector at time k+2.

[0008] The method includes the following steps:

[0009] Obtain the real-time state parameters of the permanent magnet motor system, i.e., the rotational speed at time k. and d-axis and q-axis currents , ;

[0010] Based on the real-time state parameters, the total disturbance caused by parameter perturbation and external load is observed. The total disturbance includes speed loop disturbance and flux linkage loop coupling disturbance, and is fed back to the control loop as a feedforward compensation amount.

[0011] The control loop is divided into flux linkage loop control and speed loop control. The speed loop control uses the motor speed and speed loop disturbance to predict the q-axis current command. The flux linkage loop control is predicted by the flux linkage composite predictive controller using the d and q-axis current commands and the flux linkage loop coupled disturbance to predict the expected voltage vector at time k+2.

[0012] The inverse Park transform and motor modulation control module performs an inverse Park transform on the desired voltage vector at time k+2, then modulates it using a space vector pulse width modulation algorithm, ultimately converting it into a PWM pulse signal to drive the permanent magnet motor.

[0013] Optionally, the two-step prediction flux linkage control model is based on the theoretical basis of achieving error-free tracking of the actual flux linkage value with respect to a given value at time k+2, specifically expressed as follows:

[0014] ;

[0015] In the formula, and Let be the stator flux linkages along the d and q axes at time k+2, respectively. and Given the flux linkages along the d and q axes, and Let be the desired flux linkage along the d and q axes.

[0016] Optionally, the flux linkage loop control is a process in which the flux linkage composite predictive controller predicts the desired voltage vector at time k+2 using d-axis and q-axis current commands and the flux linkage loop coupled disturbance. The corresponding control model is as follows:

[0017] In the formula, Let be the expected voltage vectors along the d and q axes at time k+2, respectively. It is the sampling period. Let be the expected flux linkages along the d and q axes at time k+2, respectively, and let be the corresponding flux linkage setpoints along the d and q axes. and It is calculated from the d and q axis current commands; It is the electric angular velocity of the motor at time k. For stator resistance, For dq axis inductance, These are the d-axis and q-axis components of the magnetic flux at time k, respectively. Let d and q be the voltage vectors along the d and q axes respectively at time k+1; These are the observed values ​​of the magnetic flux loop coupling perturbation along the d and q axes at time k+2.

[0018] Optionally, for speed loop control, the d-axis current command value is adopted. The control strategy and the construction of a two-step speed prediction controller enable the response speed to track the command speed in the shortest time and synchronously obtain the accurate q-axis current command value.

[0019] The speed loop control is achieved by using the two-step speed prediction controller to predict the q-axis current command value based on the motor speed and speed loop disturbance.

[0020] Optionally, the model for the two-step speed prediction controller to predict the q-axis current command value is as follows:

[0021]

[0022] In the formula, for The q-axis current command value at time t. for Rotational speed at any given moment; For extreme logarithms, It is the moment of inertia; It is a permanent magnet flux chain. It is the sampling period. for The rotational speed at a given time, i.e., the given value; for The q-axis current command at time t. for The observed values ​​of the rotational speed loop perturbation at each moment.

[0023] Optionally, the observation equation corresponding to the total disturbance caused by parameter perturbations and external loads is:

[0024]

[0025] In the formula, for Observed values ​​of the rotational speed loop perturbation at any given time. and These are the observed values ​​of the magnetic flux loop coupling perturbation along the d-axis and q-axis at time k+2, respectively. For stator resistance, For dq axis inductance, It is the electric angular velocity of the motor. They are respectively The rotational speed at time, the d-axis flux linkage, and the difference between the observed and actual values ​​of the q-axis flux linkage; They are respectively The rotational speed at any given time, the d-axis flux linkage, and the corresponding sliding surface of the q-axis flux linkage. These are the linear term gain and the switching term gain in the reaching law, respectively.

[0026] Secondly, the present invention also provides a control device based on the above method, comprising:

[0027] The real-time data acquisition module is used to obtain the real-time state parameters of the permanent magnet motor system, that is, the rotational speed at the current time k. and d-axis and q-axis currents , ;

[0028] A disturbance observer is used to observe the total disturbance caused by parameter perturbation and external load based on the real-time state parameters. The total disturbance includes speed loop disturbance and flux loop coupling disturbance, and is fed back to the control loop as a feedforward compensation.

[0029] The controller is divided into flux linkage loop control and speed loop control. The speed loop control uses the motor speed and speed loop disturbance to predict the q-axis current command. The flux linkage loop control is predicted by the flux linkage composite predictive controller using the d and q-axis current commands and the flux linkage loop coupled disturbance to predict the expected voltage vector at time k+2.

[0030] The inverse Park transformation module is used to perform an inverse Park transformation on the desired voltage vector at time k+2.

[0031] The motor modulation control module is used to modulate the desired voltage vector after inverse Park transformation using a space vector pulse width modulation algorithm, and finally convert it into a PWM pulse signal to drive the permanent magnet motor.

[0032] Thirdly, the present invention also provides a motor system, comprising a control device and a motor, wherein the control device is electrically / communically connected to the motor, and the control device performs motor control using the method described above.

[0033] Fourthly, the present invention also provides a computer-readable storage medium storing a computer program that is called by a processor to implement the steps of a two-step predictive robust control method for flux linkage in a permanent magnet motor system.

[0034] Fifthly, the present invention also provides a computer program product, the computer program product comprising program instructions, the computer program product being distributed as an independent control software package or directly embedded or burned into the firmware system of a permanent magnet synchronous motor servo driver, the program instructions being invoked to implement the steps of the above method.

[0035] Compared with the prior art, the present invention achieves the following progress and effects:

[0036] 1) This invention constructs a flux linkage composite predictive controller based on a two-step predictive flux linkage loop control model, realizing the prediction of the desired voltage vector at time k+2. Specifically, it aims to achieve error-free tracking of the actual flux linkage value at time k+2 with respect to the given value, focusing the control target on the more fundamental state quantity (flux linkage), thus achieving more precise and direct control of the motor's electromagnetic process. Compared to one-step delay compensation, which only considers the one-step time occupied by the algorithm calculation and assumes the inverter can execute instantly, in actual digital control, the voltage command often lags behind the motor by two steps when it actually acts. This invention's two-step delay predictive control directly locks the error-free tracking target at time k+2, first predicting the virtual state at time k+1, and then calculating the desired voltage for the next cycle, fundamentally eliminating the rigid physical delay of two steps, resulting in stronger control stability and anti-interference capability.

[0037] 2) Abandoning the conventional PI controller structure, the preferred scheme of this invention creatively integrates and optimizes the control methods of the speed loop and the current loop, and proposes a brand-new two-step speed prediction controller, namely formula (15) below; thus forming a new speed-magnetic flux composite prediction controller with a delay compensation-based two-step prediction robust control architecture. Through structural innovation, the dynamic performance is optimized and the system structure is simplified, and the dynamic performance of speed and current is improved simultaneously, thereby improving the control accuracy of the system and quantitatively aligning the control target to time k+2, completely eliminating the two-step rigid physical delay of the digital control system.

[0038] 3) The sliding mode control law proposed in this invention, namely formula (17) below, has the characteristics of simple structure and clear physical meaning. Its core algorithm does not require additional weighting factors, avoids the selection of weight coefficients in multi-objective optimization, reduces the difficulty of implementation, and is more conducive to deployment and application in actual digital control platforms.

[0039] 4) At the power generation end of the smart grid, the control technology provided by this invention can be applied to high-power permanent magnet synchronous power generation clusters of new energy sources such as wind power generation. Because of the two-step time delay compensation and strong anti-interference performance, it can effectively suppress electromagnetic torque pulsation and high-frequency current distortion caused by random wind speed fluctuations, parameter mismatch or demagnetization effect. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the basic process of the method in an embodiment of the present invention.

[0041] Figure 2 This is a schematic diagram illustrating the control principle of the method in an embodiment of the present invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0044] It should be noted that, in this document, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The presentation of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will understand that the embodiments described herein can be combined with other embodiments. The term "and / or" as used herein refers to any combination of one or more of the associated listed items, and all possible combinations, including such combinations.

[0045] This invention proposes a two-step predictive robust control method and system for flux linkage in a permanent magnet motor system. The core of this method is a composite predictive controller based on a two-step predictive flux linkage loop control model. Unlike traditional two-step predictive current methods that use current as an intermediate variable, the composite predictive controller proposed in this application is based on the theoretical principle of achieving error-free tracking of the actual flux linkage value with respect to the given value at time k+2, thus targeting the more fundamental state variable (flux linkage). Simultaneously, it incorporates total disturbance, actively suppressing the adverse effects of uncertainties such as changes in motor parameters and demagnetization of the permanent magnet, thereby significantly improving the system's control accuracy, dynamic response capability, and long-term operational reliability. Furthermore, based on the above, a two-step predictive speed controller is proposed, which, in conjunction with the composite predictive controller, forms a two-step predictive flux linkage-speed loop controller. This effectively eliminates the irreversible one-step delay effect in digital control systems, improves the flux linkage and speed control accuracy of the permanent magnet motor system, and significantly enhances the robustness of the permanent magnet motor system to parameter uncertainties and external disturbances.

[0046] Therefore, the technical idea of ​​the two-step prediction robust control method for flux linkage of a permanent magnet motor system provided by the present invention is as follows: a flux linkage composite predictive controller based on a two-step prediction flux linkage loop control model is constructed to realize the prediction of the desired voltage vector at time k+2.

[0047] Therefore, the control method includes the following steps:

[0048] Obtain the real-time state parameters of the permanent magnet motor system, i.e., the rotational speed at time k. and d-axis and q-axis currents , ;

[0049] Based on real-time state parameter observation, the total disturbance caused by parameter perturbation and external load includes speed loop disturbance and flux linkage loop coupling disturbance, and is fed back to the control loop as a feedforward compensation quantity;

[0050] The control loop is divided into flux linkage control and speed loop control. Speed ​​loop control uses motor speed and speed loop disturbance to predict q-axis current command. Flux linkage control uses flux linkage composite predictive controller to predict the desired voltage vector at time k+2 using d and q-axis current commands and flux linkage coupled disturbance.

[0051] The inverse Park transform and motor modulation control are performed by performing an inverse Park transform on the desired voltage vector at time k+2, and then modulating it through a space vector pulse width modulation algorithm, finally converting it into a PWM pulse signal to drive the permanent magnet motor.

[0052] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0053] First, addressing the uncertainties inherent in motor operation, such as internal parameter perturbations and potential demagnetization of permanent magnets, this invention conducts a sensitivity analysis on traditional two-step predictive current control. This analysis further demonstrates that it is highly susceptible to parameter influences. Therefore, when there is flux linkage parameter mismatch and rotor position detection error, the control accuracy and stability of traditional two-step predictive current control are significantly affected. The specific analysis is as follows:

[0054] The voltage vector calculated at time k takes one sampling cycle to load the inverter at time k+1, but the voltage and current signals generated by this loaded voltage vector are only completed at time k+2. The traditional two-step current prediction method requires predicting the current at time k+2. Its control objective is to directly make the current track the current setpoint without deadbeat at time k+2. This is a direct tracking control based on the electrical loop. Therefore, the current value at time k+2 is used as a substitute for the current sample value at time k+1. The delay compensation of the control strategy is completed through two-step prediction. When predicting the desired voltage at time k+2, since the time interval between adjacent control cycles is extremely small, the motor parameters and speed can be regarded as constant values.

[0055] Replacing the current sample at time k+1 with the current value at time k+2, and substituting it into the expected voltage calculation at k+2, we obtain the voltage vector output by the two-step predicted current loop controller under normal conditions:

[0056] (1)

[0057] in, and are the voltage vectors along the dq axes at times k+2 and k+1, respectively; F is the voltage input coefficient matrix. The given value for the stator current vector along the dq axis at time k+2 is... Let dq be the actual stator current vector along the dq axis at time k. This is the current coefficient matrix. This is the voltage coefficient matrix. The back electromotive force and cross-coupling term vector at time k+2 after discretization are expressed by the following function:

[0058] , , , ,

[0059] In the formula, The d-axis and q-axis components of the stator current command value at time k+2 are the d-axis and q-axis components. For dq axis inductance, For stator resistance, It is the sampling period. It is the electric angular velocity of the motor. It is a permanent magnet flux linkage.

[0060] definition Given the flux linkage mismatch rate, the following exists:

[0061] (2)

[0062] in, and These are the used and actual values ​​of the rotor permanent magnet flux linkage, respectively. In engineering applications, the motor system may have demagnetization risks or inaccurate parameter identification issues, resulting in a mismatch between the flux linkage parameters used in the predictive controller and the actual values.

[0063] When flux linkage parameter mismatch and rotor position detection inaccuracy occur, the stator flux linkage equations for the d and q axes are:

[0064] (3)

[0065] In the formula, These are the d-axis and q-axis components of the actual stator current; For the d-axis and q-axis components of the magnetic flux linkage; and These are the stator flux mismatches of the d and q axes after flux linkage parameter mismatch and rotor detection error, respectively, and their specific expressions are as follows;

[0066] (4)

[0067] In the formula, there is a deviation between the actual value and the measured value of the rotor position. .

[0068] From equations (1) and (4), the discrete state equations of the two-step predictive permanent magnet motor system for flux linkage parameter mismatch and rotor position inaccuracy can be obtained:

[0069] (5)

[0070] exist:

[0071]

[0072] In the formula, The value of the stator current vector response along the dq axis at time k+2.

[0073] The current deviation between the current response value and the command value can be obtained by solving as follows;

[0074] (6)

[0075] In the formula, These represent the d-axis and q-axis current deviations after flux linkage parameter mismatch and rotor position detection error, respectively.

[0076] Finally, integrating the previous equations, the observed values ​​of the current deviation are as follows;

[0077] (7)

[0078] As can be seen from formula (7), under the conditions of flux linkage parameter mismatch and rotor position detection error, there is a deviation between the current response value and its command value. Furthermore, the mismatch rate with motor speed and flux linkage parameters The error is related to stator resistance, system period, and rotor position error. The above derivation combines the existing sensitivity analysis method of flux linkage parameter mismatch and rotor position detection inaccuracy with the traditional two-step current predictive control technology, fully demonstrating the technical defects and obstacles of the existing technology.

[0079] Based on the traditional two-step predictive current control method, this invention further improves and derives a flux linkage composite predictive controller based on a two-step predictive flux linkage loop control model. Furthermore, in some embodiments, the speed loop control is further upgraded to construct a two-step speed predictive controller, thereby upgrading the control structure to a cascaded predictive control of the inner loop flux linkage and the outer loop speed. This targets the more fundamental state variables, flux linkage and speed, rather than the intermediate variable current, achieving more precise and direct control of the motor's electromagnetic process. Through the cascaded predictive architecture combined with disturbance compensation from a multivariable linear sliding mode observer, the instability of traditional current prediction under parameter mismatch is eliminated. The technical solution of this invention eliminates digital control delay by collecting current, speed, and position data and utilizing a discretized two-step predictive model.

[0080] For flux linkage loop control (inner loop flux linkage), the two-step predictive flux linkage loop control method of this application is analogous to the two-step predictive current loop control strategy. It requires predicting the flux linkage at time k+2. After the system delay is compensated, it can achieve error-free tracking of the actual flux linkage value at time k+2 with respect to the given value. Therefore, the following definition is made:

[0081] (8)

[0082] In the formula, and Let be the stator flux linkages along the d and q axes at time k+2, respectively. and Given the flux linkages along the d and q axes, and Let be the desired flux linkage along the d and q axes.

[0083] The dq axis command flux is obtained from the dq axis command current:

[0084] (9)

[0085] (10)

[0086] In the formula, and Let be the flux linkage coupling perturbations along the d and q axes at time k, respectively. The d-q axis voltages at time k+1 are obtained by inverse solution of equation (10). The desired output voltage at time k+2 is obtained by delaying the time:

[0087] (11)

[0088] Substituting equation (10) into equation (11), we obtain the voltage vector of the flux linkage output under two-step predictive control:

[0089] (12)

[0090] In the formula, , respectively, are the expected voltage vectors along the d and q axes at time k+2; Let be the expected flux linkages along the d and q axes at time k+2, respectively, and let be the corresponding flux linkage setpoints along the d and q axes. and ; and These are the magnetic flux linkage coupling perturbations along the d and q axes at time k+1, respectively. These are the observed values ​​of the magnetic flux loop coupling perturbation along the d and q axes at time k+2.

[0091] like Figure 2As shown, the observed values ​​of the magnetic flux linkage coupling perturbation along the dq axis at time k+2 are based on feedback from the multivariable linear sliding mode observer. The input is fed into the flux linkage composite predictive controller, and the output command voltage vector is obtained according to equation (11), which is then sent to the inverse Park transform module. It should be understood that the present invention does not limit the use of the multivariable linear sliding mode observer of this embodiment to observe flux linkage loop coupling disturbances. Referring to other existing feasible technologies to observe flux linkage disturbances also meets the requirements of the present invention and falls within the protection scope of the present invention. The multivariable linear sliding mode observer of this embodiment will be described in more detail below.

[0092] For speed loop control, this invention uses a preferred two-step speed prediction controller as an example for illustration. In other feasible embodiments, refer to other existing feasible controllers to realize the prediction of q-axis current command values. The technical solution also meets the requirements of this invention and falls within the protection scope of this invention.

[0093] The design goal of the two-step speed prediction controller is to enable the response speed to track the command speed in the shortest possible time and synchronously obtain the accurate q-axis current command value.

[0094] First, the rotation at time k+1 is predicted based on the mechanical motion equations.

[0095] Therefore, the equation for the q-axis current command output by the speed prediction controller is as follows (speed state, and then the q-axis current command for zero-delayed speed tracking target value at time k+2 can be derived from this). :

[0096] (13)

[0097] In the formula, for Shaft current setpoint.

[0098] After discretizing the mechanical motion equations of the permanent magnet motor system, the discrete state equations of the speed loop with a time delay of one hour are obtained:

[0099] (14)

[0100] In the formula, for Constant-time rotational speed loop disturbance; For extreme logarithms, Moment of inertia; , They are respectively time, Rotation speed at any given moment.

[0101] Therefore, the q-axis current command equation output by the speed prediction controller is shown in (15):

[0102] (15)

[0103] In the formula, for The q-axis current command value at time t. for Rotational speed at any given moment; Extreme logarithm, It is the moment of inertia; It is a permanent magnet flux chain. It is the sampling period. for Rotation speed at any given moment for The q-axis current command at time t. for The observed values ​​of the speed loop disturbance at each moment. The two-step predictive control speed loop control proposed in this application has better dynamic performance when faced with a sharp increase in the speed of the permanent magnet motor compared with the speed loop control implemented by the traditional PI controller.

[0104] The total disturbance caused by parameter perturbations and external loads includes speed loop disturbances and flux linkage loop coupling disturbances. The technical solution of this invention does not restrict the observation technique for the total disturbance; that is, observing the total disturbance using the observer described below or referring to existing techniques both meet the requirements of the technical solution of this invention.

[0105] In some embodiments, the observed values ​​of the speed loop disturbance are calculated from the speed disturbance. Obtained through a multivariable linear sliding mode observer The following text will explain both together:

[0106] To address parameter errors, this embodiment proposes a sliding surface design as shown in equation (16):

[0107] (16)

[0108] Among them, sliding surface , They are respectively The rotational speed at time t, the flux linkage along the d-axis, the sliding surface corresponding to the flux linkage along the q-axis, T is the sign of the matrix transpose; e is the difference between the observed and actual values ​​of the parameters; , , These are the observed values ​​for rotational speed, d-axis, and q-axis flux linkage, respectively. These represent the actual values ​​of rotational speed, d-axis, and q-axis flux linkages, respectively, and k represents the sampling time.

[0109] The sliding mode control function is shown in equation (17):

[0110] (17)

[0111] In the formula, and , and These are the reaching law parameters that determine the convergence speed and chattering level of the sliding surface; sign function . For error feedback gain, These are the linear term gain and the switching term gain in the reaching law, respectively.

[0112] Therefore, the total disturbance term caused by parameter mismatch is observed as shown in equation (18);

[0113] (18)

[0114] like Figure 2 Formula (18) shown integrates the total disturbance terms of the speed loop and the flux loop, respectively feeding back the disturbances to the flux loop and speed loop controllers to form a closed-loop control.

[0115] Among them, Lyapunov functions are used. The process of proving the stability of a linear sliding surface under multivariable disturbances is as follows:

[0116] (19)

[0117] In the formula, the dot indicates the first derivative. In engineering practice, unknown disturbances are finite, that is... , It is a boundary value, when , At that time, .

[0118] Based on the above theoretical analysis, such as Figure 1 The flowchart shown and Figure 2 The control logic diagram shown illustrates a two-step predictive robust control method for flux linkage in a permanent magnet motor system, provided by an embodiment of the present invention. The method includes the following steps:

[0119] Obtain the real-time status parameters of the permanent magnet motor system, i.e., the rotational speed. and d-axis and q-axis currents , .

[0120] The total disturbance caused by parameter perturbations and external loads is observed based on real-time state parameters. Specifically, it is the observed value of the flux linkage coupling disturbance along the dq axis at time k+2, fed back by a multivariable linear sliding mode observer. The observed values ​​of the speed loop disturbance were calculated using the speed disturbance. .

[0121] A two-step speed prediction controller utilizes motor speed and speed loop disturbance. Predict q-axis current command value ;

[0122] The flux linkage composite predictive controller utilizes d-axis and q-axis current commands. Coupled disturbance with magnetic flux ring Predict the desired voltage vector at time k+2 .

[0123] The desired voltage vector at time k+2 The command voltages of phase α and phase β in the two-phase stationary coordinate system are obtained after the inverse Park transformation.

[0124] Finally, the command voltages of the α-phase and β-phase in the two-phase stationary coordinate system are modulated by the SVPWM module to generate 6 PWM pulse signals for the operation of the permanent magnet motor.

[0125] It should be noted that the embodiments of the present invention also provide a control device, including: a real-time data acquisition module, a disturbance observer, a controller, an inverse Park transform module, and a motor modulation control module.

[0126] The real-time data acquisition module is used to obtain the real-time status parameters of the permanent magnet motor system, namely the rotational speed. and d-axis and q-axis currents , In practical applications, the real-time data acquisition module can be a sensor installed on the motor; or it can be a logic module implemented in software.

[0127] A disturbance observer is used to observe the total disturbance caused by parameter perturbations and external loads based on real-time state parameters. The total disturbance includes speed loop disturbance and flux linkage loop coupled disturbance, and is fed back to the control loop as a feedforward compensation. In some embodiments, the speed loop disturbance and flux linkage loop coupled disturbance can be observed independently by two separate observers, or they can be observed together.

[0128] The controller is divided into flux linkage loop control and speed loop control. Speed ​​loop control uses motor speed and speed loop disturbances to predict the q-axis current command. Flux linkage loop control uses a flux linkage composite predictive controller to predict the desired voltage vector at time k+2 using d-axis and q-axis current commands and flux linkage loop coupled disturbances. In some embodiments, a flux linkage composite predictive controller and a flux linkage loop controller are independently provided and interconnected.

[0129] The inverse Park transform module is connected to the controller, receives the desired voltage vector at time k+2, and performs the inverse Park transform.

[0130] The motor modulation control module is connected to the inverse Park transformation module. It is used to modulate the desired voltage vector after the inverse Park transformation through the space vector pulse width modulation algorithm, and finally convert it into a PWM pulse signal to drive the permanent magnet motor.

[0131] It should be noted that the present invention also provides a motor system, which includes a control device and a motor. The control device is electrically / communicationally connected to the motor, and the control device uses the above-described control method to control the motor.

[0132] It should be noted that the embodiments of the present invention also provide a computer-readable storage medium on which a computer program or instructions are stored. When the computer program or instructions are executed by a processor (such as a DSP, MCU, or other microprocessor), the various operational steps in the above-described two-step predictive robust control method for flux linkage of a permanent magnet motor system can be implemented.

[0133] In addition, the present invention can also provide a computer program product containing the above-mentioned program instructions, which can be distributed as a standalone control software package or directly embedded or burned into the firmware system of a permanent magnet synchronous motor servo driver.

[0134] Those skilled in the art will understand that embodiments of the present invention can be implemented entirely in hardware, entirely in software, or in a combination of hardware and software functions. Typically, the present invention can be deployed using a computer-readable storage medium (including but not limited to disk storage, non-volatile memory, optical memory, etc.) containing usable program code. The flowcharts and block diagrams presented in the specification and drawings illustrate the logical functions and execution timing of the control architecture of the present invention. Each action and combination thereof in these flowcharts or block diagrams can be implemented by a general-purpose computer, a dedicated computing platform, or an embedded data processing device that executes specific machine-readable instructions, thereby completing the functional actions specified in the two-step prediction and disturbance feedforward compensation of the present invention.

[0135] Finally, it should be noted that the above description is merely a preferred embodiment of the technical solution of the present invention, intended to elaborate on the technical logic of the invention, and not to impose an absolute limitation on the scope of protection. Any equivalent substitutions or engineering evolutions made within the core control concept and technical architecture of the present invention should be covered within the scope of protection of the present invention. For example, in the specific design of the interference observer, the linear sliding surface is extended to a higher-order sliding surface; or the coordinate system parameters of the discrete prediction model are corrected accordingly for permanent magnet motors with different configurations. For those skilled in the art, these local improvements and modifications made without departing from the basic principles of the present invention should be considered within the scope of protection of this patent.

Claims

1. A two-step predictive robust control method for flux linkage in a permanent magnet motor system, characterized in that: A flux linkage composite predictive controller based on a two-step prediction flux linkage loop control model was constructed to achieve prediction of the desired voltage vector at time k+2. The method includes the following steps: Obtain the real-time state parameters of the permanent magnet motor system, i.e., the rotational speed at time k. and d-axis and q-axis currents , ; Based on the real-time state parameters, the total disturbance caused by parameter perturbation and external load is observed. The total disturbance includes speed loop disturbance and flux linkage loop coupling disturbance, and is fed back to the control loop as a feedforward compensation amount. The control loop is divided into flux linkage loop control and speed loop control. The speed loop control uses the motor speed and speed loop disturbance to predict the q-axis current command. The flux linkage loop control is predicted by the flux linkage composite predictive controller using the d and q-axis current commands and the flux linkage loop coupled disturbance to predict the expected voltage vector at time k+2. The inverse Park transformation and motor modulation control involve performing an inverse Park transformation on the desired voltage vector at time k+2, then modulating it using a space vector pulse width modulation algorithm, and finally converting it into a PWM pulse signal to drive the permanent magnet motor.

2. The method according to claim 1, characterized in that: The two-step prediction flux linkage control model is based on the theoretical premise of achieving error-free tracking of the actual flux linkage value with respect to the given value at time k+2, and is specifically expressed as follows: ； In the formula, and Let be the stator flux linkages along the d and q axes at time k+2, respectively. and Given the flux linkages along the d and q axes, and Let be the desired flux linkage along the d and q axes.

3. The method according to claim 1, characterized in that: The flux linkage loop control is a process in which the flux linkage composite predictive controller uses d-axis and q-axis current commands and the flux linkage loop coupled disturbance to predict the desired voltage vector at time k+2. The corresponding control model is as follows: In the formula, Let be the expected voltage vectors along the d and q axes at time k+2, respectively. It is the sampling period. Let be the expected flux linkages along the d and q axes at time k+2, respectively, and let be the corresponding flux linkage setpoints along the d and q axes. and It is calculated from the d and q axis current commands; It is the electric angular velocity of the motor at time k. For stator resistance, For dq axis inductance, These are the d-axis and q-axis components of the magnetic flux at time k, respectively. Let d and q be the voltage vectors along the d and q axes respectively at time k+1; These are the observed values ​​of the magnetic flux linkage coupling perturbation along the d and q axes at time k+2.

4. The method according to claim 1, characterized in that: For speed loop control, the d-axis current command value is adopted. The control strategy and the construction of a two-step speed prediction controller enable the response speed to track the command speed in the shortest time and synchronously obtain the accurate q-axis current command value. The speed loop control is achieved by using the two-step speed prediction controller to predict the q-axis current command value based on the motor speed and speed loop disturbance.

5. The method according to claim 4, characterized in that: The model for the two-step speed prediction controller to predict the q-axis current command value is as follows: ； In the formula, This represents the q-axis current command value at time k+2. for Rotational speed at any given moment; For extreme logarithms, It is the moment of inertia; It is a permanent magnet flux chain. It is the sampling period. for The rotational speed at a given time, i.e., the given value. for The q-axis current command at time t. for The observed values ​​of the rotational speed loop perturbation at each moment.

6. The method according to claim 1, characterized in that: The observation equation corresponding to the total disturbance caused by parameter perturbation and external load is: In the formula, for Observed values ​​of the rotational speed loop perturbation at any given time. and These are the observed values ​​of the magnetic flux loop coupling perturbation along the d-axis and q-axis at time k+2, respectively. For stator resistance, For dq axis inductance, It is the electric angular velocity of the motor. They are respectively The rotational speed at time, the d-axis flux linkage, and the q-axis flux linkage are the differences between the observed and actual values. They are respectively The rotational speed at a given moment, the d-axis flux linkage, and the corresponding sliding surface of the q-axis flux linkage. These are the linear term gain and the switching term gain in the reaching law, respectively.

7. A control device based on the method of any one of claims 1-6, characterized in that: include: The real-time data acquisition module is used to obtain the real-time state parameters of the permanent magnet motor system, that is, the rotational speed at the current time k. and d-axis and q-axis currents , ; A disturbance observer is used to observe the total disturbance caused by parameter perturbation and external load based on the real-time state parameters. The total disturbance includes speed loop disturbance and flux loop coupling disturbance, and is fed back to the control loop as a feedforward compensation. The controller is divided into flux linkage loop control and speed loop control. The speed loop control uses the motor speed and speed loop disturbance to predict the q-axis current command. The flux linkage loop control is predicted by the flux linkage composite predictive controller using the d and q-axis current commands and the flux linkage loop coupled disturbance to predict the expected voltage vector at time k+2. The inverse Park transformation module is used to perform an inverse Park transformation on the desired voltage vector at time k+2. The motor modulation control module is used to modulate the desired voltage vector after inverse Park transformation using a space vector pulse width modulation algorithm, and finally convert it into a PWM pulse signal to drive the permanent magnet motor.

8. A motor system, characterized in that: The device includes a control unit and a motor. The control unit is electrically / communically connected to the motor. The control unit controls the motor using the method described in any one of claims 1-6.

9. A computer-readable storage medium, characterized in that: A computer program is stored, which is invoked by a processor to implement the steps of the method according to any one of claims 1-6.

10. A computer program product, characterized in that, The computer program product includes program instructions, which are distributed as an independent control software package or directly embedded or burned into the firmware system of the permanent magnet synchronous motor servo driver, and the program instructions are invoked to implement the steps of the method according to any one of claims 1-6.

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