Motor control method, system and device based on flux observer and medium

Abstract

The invention discloses a motor control method, system and device based on a flux observer and a medium, and relates to the field of motor control. In the scheme, a nonlinear flux linkage observer model is constructed in advance, and the input of the nonlinear flux linkage observer model at least comprises q-axis current; then obtaining an electrical angular velocity estimated value and an electrical angle estimated value of the motor through a nonlinear flux observer model; and according to the electrical angular velocity estimation value and the electrical angle estimation value, inputting the electrical angular velocity estimation value and the electrical angle estimation value into operation of a speed loop and a current loop to control the motor. According to the motor control method provided by the invention, the q-axis current is considered in the established nonlinear flux linkage observation model, and the q-axis current is closely related to the dynamic inductance and then is related to the error of the electrical angular velocity estimated value and the electrical angle estimated value; according to the invention, the error of the dynamic inductance to the electrical angular velocity estimation value and the electrical angle estimation value can be reduced, and the accuracy of motor control is improved.

Description

Technical Field

[0001] The present application relates to the field of motor control, and in particular to a motor control method, system, device and medium based on a flux observer. Background Art

[0002] In the field of household appliances, in order to save industrial costs, sensorless control is usually adopted. The core idea is to estimate the position or speed of the motor rotor through an observer. However, during the operation of the motor, the change of current will produce magnetic circuit saturation phenomenon and change the inductance coefficient (also known as dynamic inductance), thereby affecting the observer's estimation of the motor's electrical angle and electrical angular velocity. If the estimation is inaccurate, the control effect of the motor may be affected, and the motor may not achieve the expected goal. Summary of the invention

[0003] The purpose of the present application is to provide a motor control method, system, device and medium based on a flux observer. The q-axis current is taken into account in the established nonlinear flux observation model. Since the q-axis current is closely related to the dynamic inductance, and thus to the errors in the estimated electric angular velocity and the estimated electric angle, the error of the dynamic inductance on the estimated electric angular velocity and the estimated electric angle can be reduced through the method of the present application, thereby improving the accuracy of motor control.

[0004] In order to solve the above technical problems, the present application provides a motor control method based on a flux observer, comprising:

[0005] Pre-constructing a nonlinear flux observer model, wherein the input of the nonlinear flux observer model at least includes a q-axis current;

[0006] Obtaining an estimated value of the electrical angular velocity and an estimated value of the electrical angle of the motor through the nonlinear flux observer model;

[0007] generating a q-axis reference current according to the electrical angular velocity estimation value and a reference angular velocity;

[0008] Performing park transformation on the α-axis current and the β-axis current according to the electrical angle estimation value to obtain the d-axis actual current and the q-axis actual current;

[0009] Generate a d-axis voltage and a q-axis voltage through a current loop controller according to the d-axis reference current, the d-axis actual current, the q-axis reference current, and the q-axis actual current;

[0010] Park inverse transformation is performed according to the electrical angle estimation value, the d-axis voltage and the q-axis voltage to obtain the α-axis voltage and the β-axis voltage, and a PWM signal is generated according to the α-axis voltage and the β-axis voltage to control the motor.

[0011] Preferably, the input of the nonlinear flux observer model further includes the α-axis voltage, the β-axis voltage, the α-axis current and the β-axis current.

[0012] Preferably, obtaining the estimated value of the electrical angular velocity and the estimated value of the electrical angle of the motor through the nonlinear flux observer model includes:

[0013] Obtaining a first observation value of the rotor flux on the α-axis using an α-axis flux observer model according to the q-axis current, the α-axis current and the α-axis voltage;

[0014] Obtaining a second observation value of the rotor flux on the β-axis using a β-axis flux observer model according to the q-axis current, the β-axis current and the β-axis voltage;

[0015] The first observation value and the second observation value are processed by a phase-locked loop structure to obtain the electrical angle estimation value and the electrical angle estimation value.

[0016] Preferably, it also includes:

[0017] Acquire the corresponding relationship between the q-axis current and the dynamic inductance, and determine the current dynamic inductance based on the current q-axis current and the corresponding relationship;

[0018] The method comprises: obtaining a first observation value of the rotor flux on the α-axis by using an α-axis flux observer model according to the q-axis current, the α-axis current and the α-axis voltage; and obtaining a second observation value of the rotor flux on the β-axis by using a β-axis flux observer model according to the q-axis current, the β-axis current and the β-axis voltage, including:

[0019] The α-axis flux observer model is used to obtain a first observation value of the rotor flux on the α-axis according to the current dynamic inductance, the α-axis current and the α-axis voltage; the β-axis flux observer model is used to obtain a second observation value of the rotor flux on the β-axis according to the current dynamic inductance, the β-axis current and the β-axis voltage.

[0020] Preferably, it also includes:

[0021] Negatively feeding back the first observation value to the input end of the α-axis flux observer model to perform closed-loop control on the first observation value;

[0022] The second observation value is negatively fed back to the input end of the β-axis flux observer model to perform closed-loop control on the second observation value.

[0023] Preferably, the nonlinear flux observer model is:

[0024]

[0025] in, is the α-axis stator flux component at time k, T is the sampling time, u sα (k) is the α-axis voltage at time K, R s is the stator resistance, i sα (k) is the α-axis current at time k, G fb is the negative feedback gain, is the first observation value at time k-1, is the α-axis stator flux component at time k-1; is the first observation value at time k, is the α-axis stator flux component at time k, is the dynamic inductance value corresponding to the q-axis current; is the second observation value at time k, is the β-axis stator flux component at time k, i sβ (k) is the β-axis current at time k, is the second observation value at time k-1, is the β-axis stator flux component at time k-1.

[0026] Preferably, it also includes:

[0027] Compensating the electrical angle estimation value to obtain a compensated electrical angle estimation value;

[0028] Performing a Park inverse transformation according to the electrical angle estimation value, the d-axis voltage, and the q-axis voltage to obtain an α-axis voltage and a β-axis voltage, and generating a PWM signal according to the α-axis voltage and the β-axis voltage to control the motor, including:

[0029] An inverse park transformation is performed on the compensated electrical angle estimation value, the d-axis voltage and the q-axis voltage to obtain an α-axis voltage and a β-axis voltage, and a PWM signal is generated based on the α-axis voltage and the β-axis voltage to control the motor.

[0030] Preferably, compensating the electrical angle estimation value to obtain the compensated electrical angle estimation value comprises:

[0031] Obtaining a cutoff frequency of a low-pass filter in the phase-locked loop structure;

[0032] Calculate the compensation angle by using a preset formula according to the cut-off frequency and the estimated value of the electrical angle;

[0033] The compensation angle is superimposed on the electrical angle estimation value to obtain the compensated electrical angle estimation value.

[0034] Preferably, the preset formula is: in, is the compensation angle, is the estimated value of the electrical angular velocity, ω comp is the cut-off frequency.

[0035] In order to solve the above technical problems, the present application also provides a motor control system based on a flux observer, comprising:

[0036] A model building unit, used for pre-building a nonlinear flux observer model, wherein the input of the nonlinear flux observer model at least includes a q-axis current;

[0037] An estimation unit, used for obtaining an estimated value of an electrical angular velocity and an estimated value of an electrical angle of the motor through the nonlinear flux observer model;

[0038] A speed loop control unit, used for generating a q-axis reference current according to the electrical angular velocity and a reference angular velocity;

[0039] A park transformation unit, configured to perform park transformation on the α-axis current and the β-axis current according to the electrical angle estimation value to obtain the d-axis actual current and the q-axis actual current;

[0040] A current loop control unit, used for generating a d-axis voltage and a q-axis voltage through a current loop PI controller according to a d-axis reference current, the d-axis actual current, the q-axis reference current, and the q-axis actual current;

[0041] A motor control unit is used to perform a park inverse transformation according to the electrical angle estimation value, the d-axis voltage and the q-axis voltage to obtain an α-axis voltage and a β-axis voltage, and to generate a PWM signal according to the α-axis voltage and the β-axis voltage to control the motor.

[0042] In order to solve the above technical problems, the present application also provides a motor control device based on a flux observer, comprising:

[0043] Memory for storing computer programs;

[0044] The processor is used to implement the steps of the motor control method based on the flux observer as described above when storing the computer program.

[0045] In order to solve the above technical problems, the present application also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the motor control method based on the flux observer as described above are implemented.

[0046] The present application provides a motor control method, system, device and medium based on a flux observer, which relates to the field of motor control. In this scheme, a nonlinear flux observer model is pre-constructed, and the input of the nonlinear flux observer model includes at least the q-axis current; then the motor's electrical angular velocity estimation value and electrical angle estimation value are obtained through the nonlinear flux observer model; the electrical angular velocity estimation value and electrical angle estimation value are input into the operation of the speed loop and the current loop to achieve control of the motor. The motor control method of the present application takes the q-axis current into account in the established nonlinear flux observation model. Since the q-axis current is closely related to the dynamic inductance, and thus to the error of the electrical angular velocity estimation value and the electrical angle estimation value, the method of the present application can reduce the error of the dynamic inductance to the electrical angular velocity estimation value and the electrical angle estimation value, thereby improving the accuracy of motor control. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the prior art and the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 A block diagram of a motor control system provided for this application;

[0049] Figure 2 A flow chart of a motor control method based on a flux observer provided in this application;

[0050] Figure 3 A schematic diagram of an α-axis flux observer model provided in this application;

[0051] Figure 4 A schematic diagram of a β-axis flux observer model provided in this application;

[0052] Figure 5 A schematic diagram of a phase-locked loop structure provided in this application;

[0053] Figure 6 A schematic block diagram of a phase-locked loop and a phase compensation link provided by the present application;

[0054] Figure 7 The corresponding relationship between the q-axis current and the dynamic inductance provided in this application;

[0055] Figure 8 A structural block diagram of a motor control system based on a flux observer provided in this application;

[0056] Fig. 9This is a structural block diagram of a motor control device based on a flux observer provided in this application. DETAILED DESCRIPTION

[0057] The core of the present application is to provide a motor control method, system, device and medium based on a flux observer. The q-axis current is taken into account in the established nonlinear flux observation model. Since the q-axis current is closely related to the dynamic inductance, and thus to the errors in the estimated electric angular velocity and the estimated electric angle, the method of the present application can reduce the errors in the dynamic inductance on the estimated electric angular velocity and the estimated electric angle, thereby improving the accuracy of motor control.

[0058] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0059] Please refer to Figure 1 , Figure 1 A block diagram of a motor control system provided in this application, Figure 1 In the system, the main body adopts vector control with id=0, and the current loop and speed loop both adopt feedback suppression anti-saturation PI regulator. The frequency conversion chip first collects the DC bus voltage and three-phase current through ADC. The three-phase current is transformed by CLARKE and PARK to generate αβ and dq axis currents respectively, and participates in the current loop control to calculate the dq axis voltage, and then generates the αβ axis voltage through the park inverse transformation, and then participates in the SVPWM calculation with the bus voltage to generate the duty cycle, realizing the frequency conversion function. The system calculates the dynamic inductance through the q axis current, and inputs it into the nonlinear flux observer together with the αβ axis current and voltage to estimate the rotor flux, and uses PLL and phase compensation links to extract real-time electrical angle signals and angular velocity signals from the rotor flux. The angular velocity signal participates in the speed loop control to generate the q axis current reference, and the angle signal participates in the PARK transformation and the PARK inverse transformation.

[0060] Please refer to Figure 2 , Figure 2 A flow chart of a motor control method based on a flux observer provided in this application, the method comprising:

[0061] S1: pre-build a nonlinear flux observer model, where the input of the nonlinear flux observer model at least includes the q-axis current;

[0062] S2: Obtain the estimated electrical angular velocity and electrical angle of the motor through the nonlinear flux observer model;

[0063] In the motor control system, using an observer to estimate the electrical angle and electrical angular velocity of the motor is a key step. However, the dynamic inductance changes inside the motor will interfere with the estimation results of the observer, thereby affecting the control effect.

[0064] Specifically, the nonlinear flux observer model can infer the magnitude and direction of the motor's flux through the motor's q-axis current, α-axis current, α-axis voltage, β-axis current, and β-axis voltage. Therefore, in this embodiment, a motor observer based on the nonlinear flux observer model is pre-constructed, and the q-axis current that can reflect the dynamic inductance is used as input to accurately estimate the motor's electrical angle and electrical angular velocity, thereby improving the accuracy and stability of motor control.

[0065] In one embodiment, the input of the nonlinear flux observer model includes not only the q-axis current but also the d-axis current. In another embodiment, as a preferred embodiment, the input of the nonlinear flux observer model also includes the α-axis voltage, the β-axis voltage, the α-axis current and the β-axis current.

[0066] S3: Generate a q-axis reference current according to the electrical angular velocity estimation value and the reference angular velocity;

[0067] In the motor control system, the motor is controlled by adjusting the current, and the q-axis reference current is generated based on the error between the estimated electrical angular velocity and the reference angular velocity to achieve precise control of the motor.

[0068] The speed loop may be, but is not limited to, a PI regulator that uses feedback to suppress saturation. The PI regulator adjusts the error signal to control the magnitude of the q-axis reference current, thereby achieving control of the motor.

[0069] By generating the q-axis reference current, precise control of the motor can be achieved, thereby improving the accuracy and stability of the motor control system.

[0070] S4: Park transformation is performed on the α-axis current and the β-axis current according to the electrical angle estimation value to obtain the d-axis actual current and the q-axis actual current;

[0071] Specifically, the electrical angle estimation value can be used to calculate the sin and cos functions, thereby performing park transformation on the α-axis current and the β-axis current to obtain the d-axis actual current and the q-axis actual current. This step achieves accurate adjustment of the α-axis current and the β-axis current by applying the electrical angle estimation value to the park transformation, thereby improving the accuracy and stability of the motor control.

[0072] S5: Generate a d-axis voltage and a q-axis voltage through a current loop controller according to the d-axis reference current, the d-axis actual current, the q-axis reference current, and the q-axis actual current;

[0073] Specifically, by comparing the difference between the d-axis reference current and the actual current, and the q-axis reference current and the actual voltage, the d-axis voltage and the q-axis voltage are calculated, thereby controlling the operation of the motor. The current loop controller can use a PI regulator with feedback suppression and anti-saturation. In a current control system based on a PI controller, the d-axis reference current and the d-axis actual current can be compared, and the d-axis voltage output by the PI controller can be controlled by an error signal. Similarly, the q-axis reference current and the q-axis actual current can also be compared, and the q-axis voltage output by the PI controller can be controlled by an error signal, thereby controlling the operation of the motor.

[0074] By accurately calculating the d-axis voltage and the q-axis voltage according to the difference between the actual current and the reference current, precise control of the motor is achieved, thereby improving the accuracy and stability of the motor control system.

[0075] S6: Performing inverse park transformation according to the electrical angle estimation value, the d-axis voltage and the q-axis voltage to obtain the α-axis voltage and the β-axis voltage, and generating a PWM signal according to the α-axis voltage and the β-axis voltage to control the motor.

[0076] The sin and cos functions are calculated according to the electrical angle, α-axis voltage and β-axis voltage, and the α-axis voltage and β-axis voltage are subjected to park inverse transformation to obtain the required output duty cycle, and then a PWM signal is generated according to the duty cycle to control the operation of the motor.

[0077] By applying the electrical angle estimation value to the park inverse transformation, the park inverse transformation is realized according to the electrical angle estimation value and the α-axis voltage and the β-axis voltage, and then a PWM signal is generated to control the operation of the motor and improve the accuracy and stability of the motor control system.

[0078] In summary, the motor control method in the present application takes the q-axis current into account in the established nonlinear flux observation model. Since the q-axis current is closely related to the dynamic inductance, and thus related to the errors in the estimated electric angular velocity and the estimated electric angle, the method of the present application can reduce the errors in the dynamic inductance on the estimated electric angular velocity and the estimated electric angle, thereby improving the accuracy of motor control.

[0079] Based on the above embodiments:

[0080] As a preferred embodiment, obtaining the estimated value of the electrical angular velocity and the estimated value of the electrical angle of the motor through a nonlinear flux observer model includes:

[0081] The first observation value of the rotor flux on the α-axis is obtained by using the α-axis flux observer model according to the q-axis current, the α-axis current and the α-axis voltage;

[0082] A second observation value of the rotor flux on the β axis is obtained using a β axis flux observer model according to the q axis current, the β axis current and the β axis voltage;

[0083] The first observation value and the second observation value are processed by a phase-locked loop structure to obtain an electrical angle estimation value and an electrical angle estimation value.

[0084] Please refer to Figure 3 , Figure 4 , Figure 3 A schematic diagram of an α-axis flux observer model provided in this application, Figure 4 This is a schematic diagram of a β-axis flux observer model provided in this application. The structure of the phase-locked loop can be referred to Figure 5 The existing technical problem is that in the motor control system, the dynamic inductance change inside the motor will interfere with the estimation of the electrical angle and electrical angular velocity of the motor, thereby reducing the accuracy and stability of the estimation.

[0085] In this embodiment, a nonlinear flux observer model (specifically including an α-axis flux observer model and a β-axis flux observer model) is pre-constructed, and the q-axis current, α-axis current and α-axis voltage, β-axis current and β-axis voltage are input into the flux observer model to obtain a first observation value and a second observation value of the rotor flux on the α-axis and the β-axis (specifically, the q-axis current, α-axis current and α-axis voltage are input into the α-axis flux observer model to obtain a first observation value of the rotor flux on the α-axis, such as Figure 3 As shown; the q-axis current, β-axis current and β-axis voltage are input into the β-axis flux observer model to obtain the second observation value of the rotor flux on the β-axis, as shown Figure 4 As shown), the electrical angular velocity and the electrical angle are estimated (the first observation value and the second observation value are processed by a phase-locked loop structure to obtain an electrical angle estimation value and an electrical angle estimation value), thereby reducing the influence of dynamic inductance on the estimation accuracy and stability.

[0086] At the same time, by processing the estimated value through the phase-locked loop structure, the system can be made more stable and the effect of motor control can be improved.

[0087] The core of this embodiment is to use a nonlinear flux observer model to estimate the electrical angle and electrical angular velocity. By modeling the relationship between the q-axis current and the dynamic inductance, the electrical angular velocity and electrical angle can be estimated more accurately, thereby improving the accuracy and stability of the motor control system.

[0088] As a preferred embodiment, it also includes:

[0089] Obtaining the corresponding relationship between the q-axis current and the dynamic inductance, and determining the current dynamic inductance based on the current q-axis current and the corresponding relationship;

[0090] The first observation value of the rotor flux on the α-axis is obtained by using the α-axis flux observer model according to the q-axis current, the α-axis current and the α-axis voltage; the second observation value of the rotor flux on the β-axis is obtained by using the β-axis flux observer model according to the q-axis current, the β-axis current and the β-axis voltage, including:

[0091] According to the current dynamic inductance, α-axis current and α-axis voltage, the α-axis flux observer model is used to obtain the first observation value of the rotor flux on the α-axis; according to the current dynamic inductance, β-axis current and β-axis voltage, the β-axis flux observer model is used to obtain the second observation value of the rotor flux on the β-axis.

[0092] In a motor control system, changes in the dynamic inductance inside the motor will have an adverse effect on the observer's estimation of the motor's electrical angle and electrical angular velocity, thereby reducing the accuracy and stability of the estimation.

[0093] Please refer to Figure 7 , Figure 7 The correspondence between the q-axis current and the dynamic inductance provided in this application is related to the dynamic inductance and has a corresponding relationship. Therefore, in this embodiment, by obtaining the correspondence between the q-axis current and the dynamic inductance, the current dynamic inductance value can be determined, and the size and direction of the rotor flux in the α-axis and β-axis can be obtained by combining the α-axis flux observer model and the β-axis flux observer model, and finally the estimated value is processed using the phase-locked loop structure to finally obtain the estimated value of the electrical angle and electrical angular velocity. It can improve the accurate estimation of the motor electrical angle and electrical angular velocity, and enhance the accuracy and stability of the motor control system.

[0094] Compared with the above embodiment, in this embodiment, the prediction and processing of dynamic inductance are added to the process of estimating the electrical angle and electrical angular velocity. In this way, the influence of dynamic inductance on the estimation of the electrical angle and electrical angular velocity of the motor can be better suppressed. In addition, when using the phase-locked loop structure for processing, this embodiment also uses the α-axis flux observer model and the β-axis flux observer model to estimate the size and direction of the rotor flux on the two axes according to the current dynamic inductance, thereby improving the accuracy of the estimation.

[0095] In a specific implementation, the dynamic inductance value can also be predicted by calibrating the relationship between the q-axis current and the dynamic inductance. After the dynamic inductance value is predicted, the rotor flux on the α-axis and β-axis can be estimated using the flux observer based on the predicted value. This method can more accurately estimate the electrical angle and electrical angular velocity, thereby more effectively controlling the motor.

[0096] In addition, the specific implementation method in this embodiment can also enhance the robustness of the motor system to abnormal situations. Since the motor will face various interferences and disturbances during operation, these situations may affect the stability of the motor control system and cause the motor to fail to achieve the expected goals. In this embodiment, by adding dynamic inductance processing, the robustness of the motor control system can be improved, so that it can effectively respond to various interferences and disturbances, thereby improving the reliability and stability of the motor system.

[0097] In summary, the specific implementation method of this embodiment improves the accurate estimation of the motor electrical angle and electrical angular velocity by predicting the dynamic inductance and combining the flux observer model, so that the motor control system has more accuracy and stability, and can enhance the robustness of the motor system to abnormal situations.

[0098] As a preferred embodiment, it also includes:

[0099] Negatively feeding back the first observation value to the input end of the α-axis flux observer model to perform closed-loop control on the first observation value;

[0100] The second observation value is negatively fed back to the input end of the β-axis flux observer model to perform closed-loop control on the second observation value.

[0101] Specifically, in this embodiment, the first observation value and the second observation value are respectively negatively fed back to the input end of the corresponding flux observer model for closed-loop control, so as to improve the accuracy and stability of the nonlinear flux observer model.

[0102] The closed-loop control in this embodiment can improve the accuracy and stability of the nonlinear flux observer model, thereby making the motor control more accurate and efficient. In addition, the method can effectively suppress the influence of the dynamic induced electromotive force on the motor and improve the operating efficiency and stability of the motor.

[0103] As a preferred embodiment, it also includes:

[0104] Compensating the electrical angle estimation value to obtain a compensated electrical angle estimation value;

[0105] Performing inverse park transformation according to the electrical angle estimation value, the d-axis voltage, and the q-axis voltage to obtain the α-axis voltage and the β-axis voltage, and generating a PWM signal according to the α-axis voltage and the β-axis voltage to control the motor, including:

[0106] The α-axis voltage and the β-axis voltage are obtained by performing an inverse park transformation on the compensated electrical angle estimation value, the d-axis voltage and the q-axis voltage, and a PWM signal is generated according to the α-axis voltage and the β-axis voltage to realize the control of the motor.

[0107] When the motor rotates at high speed, there is a certain phase lag in the angle estimation; or the dynamic inductance has a certain influence on the angle estimation value, so the estimated angle needs to be compensated to improve the control accuracy and stability.

[0108] The electrical angle estimation value compensation method involved in this embodiment is based on a nonlinear flux observer model and park inverse transformation. Through the compensated electrical angle estimation value, more accurate α-axis voltage and β-axis voltage are obtained, thereby improving the control accuracy and stability of the motor.

[0109] The electrical angle estimation value compensation method in this embodiment can further effectively eliminate the influence of inaccurate electrical angle estimation value on motor control, improve control accuracy and stability, thereby more accurately controlling the running state of the motor and improving the efficiency and performance of the motor.

[0110] As a preferred embodiment, compensating the electrical angle estimation value to obtain the compensated electrical angle estimation value includes:

[0111] Get the cutoff frequency of the low-pass filter in the phase-locked loop structure;

[0112] Calculate the compensation angle using a preset formula based on the cut-off frequency and the estimated electrical angle value;

[0113] The compensation angle is added to the estimated electrical angle to obtain the compensated estimated electrical angle.

[0114] In motor control, the accuracy of electrical angle estimation is crucial to the control of motor operation status. However, traditional electrical angle estimation methods are affected by factors such as dynamic inductance and noise, and are prone to errors, which in turn affect the motor control accuracy and stability. Therefore, appropriate compensation methods are needed to improve the accuracy and reliability of electrical angle estimation.

[0115] like Figure 6 , Figure 6 This is a schematic block diagram of the phase-locked loop and phase compensation link provided in this application.

[0116] In the phase-locked loop structure, the PI controller acts as a low-pass filter, which has the functions of denoising and smoothing signals, and can also be used to calculate frequency or angular velocity. In this embodiment, the low-pass filter in the phase-locked loop structure is used to obtain the estimated value of the electrical angular velocity, and the compensation angle is calculated by a preset formula, and finally the compensation angle is superimposed on the estimated value of the electrical angle for compensation, thereby improving the accuracy and reliability of the electrical angle estimation.

[0117] As a preferred embodiment, the preset formula is: in, is the compensation angle, is the estimated value of the electric speed angle, ω compis the cut-off frequency.

[0118] In addition to calculating the compensation angle through the low-pass filter in the phase-locked loop structure, other methods can also be used to compensate the estimated electrical angle value. For example, compensation can be performed by establishing a dynamic inductance model and a neural network model. In addition, model predictive control can also be used to perform more accurate motor control.

[0119] The compensation method of this embodiment can effectively improve the accuracy and stability of electrical angle estimation, reduce motor control errors, and thus achieve more refined motor control. This method is simple and easy to implement, has good feasibility and practicality, and is applicable to various types of motor control systems.

[0120] In a specific embodiment, the process of this application is as follows:

[0121] The mathematical model of the motor mainly includes the voltage equation and the flux equation, which are

[0122]

[0123] ψ s =L s i s +ψ f (2)

[0124] in, u s is the stator voltage, i s Stator current, R s is the stator voltage, ψ s is the stator flux, ψ f is the rotor flux, R s is the stator resistance, L s is the stator inductance, ω e is the motor electrical angular velocity, is the induced potential, which is generated by the induced potential ωL s i s and motional potential ωψ f constitute.

[0125] The voltage equation (1) is projected onto the α-β axis:

[0126]

[0127] where u sα 、u sβ is the α-β axis stator voltage component, i sα 、i sβ is the α-β axis stator current component, ψ sα , sβ is the stator flux component of the α-β axis.

[0128] The magnetic flux equation (2) is projected onto the α-β axis:

[0129]

[0130] Among them, ψ fα , fβ It is the projection of the rotor magnetic flux on the α and β axes.

[0131] Second, dynamic inductance linear fitting

[0132] In surface-mount motors, the estimated angle error is essentially related to the q-axis current and is expressed as Figure 7 As can be seen from the figure, the dynamic change of inductance is nonlinear with i q In order to facilitate the calculation of the processor (mainly because when the corresponding relationship between inductance and q-axis current is directly calculated nonlinearly, more data needs to be analyzed and the amount of calculation is large), the dynamic inductance is fitted by linear interpolation (within a certain linear interval, the dynamic inductance and q-axis current are considered to be a linear relationship), such as Figure 7 As shown by the solid line. (For example, when divided into seven equal parts, the formula is as follows:

[0133]

[0134] The purpose of observing the flux is to obtain the estimated value of the electrical angle and electrical angular velocity of the motor, and the information of the electrical angle is contained in the flux components of the αβ axis. In formula (3), the αβ flux is completely decoupled, so the flux observer can be designed separately. Taking the α axis as an example, the stator flux observation equation is as shown in formula (6). By introducing the dynamic inductance of formula (5), the rotor flux observation equation is obtained as shown in formula (7):

[0135]

[0136]

[0137] In the above formula, It is the observed value of the rotor and stator magnetic flux on the α-axis.

[0138] Third, nonlinear flux observer design

[0139] Figure 3 A schematic diagram of an α-axis flux observer model provided in this application, Figure 4 A schematic diagram of a β-axis flux observer model provided in this application.

[0140] When the motor is disturbed by unbalanced torque, the voltage and current in the system will deviate from the ideal sine wave, resulting in integral drift in the observation of stator flux in equation (7), and the system lag becomes more serious with the increase of time. Therefore, in order to eliminate this influence and improve the stability of the system, the observer outputs negative feedback, and a team outputs closed-loop control, where the feedback gain is G fb .

[0141] The above formula can be rewritten as

[0142]

[0143]

[0144] Substituting equation (9) into equation (8), the stator flux observation differential equation is:

[0145]

[0146] The formula (10) is discretized into

[0147]

[0148] Arranged:

[0149]

[0150]

[0151] Similarly, the β-axis flux observer can be written as

[0152]

[0153]

[0154] Observer Structure Box Figure 2 As shown, only one parameter G needs to be adjusted fb , the implementation is simple and the amount of calculation is extremely small.

[0155] As a preferred embodiment, the nonlinear flux observer model is:

[0156]

[0157] in, is the α-axis stator flux component at time k, T is the sampling time, u sα (k) is the α-axis voltage at time K, R s is the stator resistance, i sα (k) is the α-axis current at time k, G fb is the negative feedback gain, is the first observation value at time k-1, is the α-axis stator flux component at time k-1; is the first observation value at time k, is the α-axis stator flux component at time k, is the dynamic inductance value corresponding to the q-axis current; is the second observation value at time k, is the β-axis stator flux component at time k, i sβ (k) is the β-axis current at time k, is the second observation value at time k-1, is the β-axis stator flux component at time k-1.

[0158] This is the above formula (11)-(15).

[0159] Fourth, phase-locked loop design

[0160] The motor electrical angle signal is contained in the rotor flux, so a phase-locked loop is designed to extract the angle signal. The structure is as follows: Figure 5 , Figure 5 A schematic diagram of a phase-locked loop structure provided in this application. Figure 5 The PLL uses PI to achieve low-pass filtering (equivalent to LPF (low-pass filter)), with electrical angular velocity Phase-locked loop electrical angle The introduced PI acts as an LPF in the phase-locked loop structure and has low-pass filtering properties.

[0161] Fifth, phase compensation link design

[0162] Please refer to Figure 6 , Figure 6 This is a structural diagram of the phase-locked loop and phase compensation link provided in this application.

[0163] When the motor rotates at high speed, there is a certain phase lag in the angle estimation, so the estimated angle needs to be compensated. If the cutoff frequency of the PI (low-pass filter) in the phase-locked loop structure is ω comp , then the compensation angle is After compensation, the electrical angle of the rotor

[0164] The PI discrete form of the present invention adopts:

[0165] u(k)=u p (k)+u i (k-1)+Δu i (k) = u p (k)+u i (k-1)+Tk i e(k);

[0166] Among them, Δu i (k) is the increment of the integral control quantity at time k. The corresponding PLL discretization formula (16-18) and phase compensation discretization formula (19-20) can be obtained using this PI discretization form:

[0167]

[0168]

[0169]

[0170]

[0171]

[0172] In summary, the purpose of the nonlinear flux observer constructed in this application is to observe the flux of the built-in motor. The dynamically changing dynamic inductance (introducing the q-axis current) is introduced as the input of the observer to improve the accuracy of the observed flux. In addition, the hysteresis of the phase-locked loop extraction angle is phase compensated. The impact of the dynamic change of inductance on the estimation error of the observer can be reduced, and the load capacity of the motor and the control performance of the system are improved.

[0173] Please refer to Figure 8 , Figure 8 The present application provides a structural block diagram of a motor control system based on a flux observer, the system comprising:

[0174] A model building unit 81 is used to pre-build a nonlinear flux observer model, wherein the input of the nonlinear flux observer model at least includes a q-axis current;

[0175] An estimation unit 82, used for obtaining an estimated value of an electrical angular velocity and an estimated value of an electrical angle of the motor through a nonlinear flux observer model;

[0176] A speed loop control unit 83, used to generate a q-axis reference current according to the electrical angular velocity and the reference angular velocity;

[0177] A park transformation unit 84 is used to perform park transformation on the α-axis current and the β-axis current according to the electrical angle estimation value to obtain the d-axis actual current and the q-axis actual current;

[0178] A current loop control unit 85, configured to generate a d-axis voltage and a q-axis voltage through a current loop controller according to a d-axis reference current, a d-axis actual current, a q-axis reference current, and a q-axis actual current;

[0179] The motor control unit 86 is used to perform inverse park transformation according to the electrical angle estimation value, the d-axis voltage and the q-axis voltage to obtain the α-axis voltage and the β-axis voltage, and generate a PWM signal according to the α-axis voltage and the β-axis voltage to control the motor.

[0180] For an introduction to the motor control system based on the flux observer, please refer to the above embodiments, and this application will not go into details here.

[0181] Please refer to Fig. 9 , Fig. 9 The present invention provides a block diagram of a motor control device based on a flux observer, the device comprising:

[0182] A memory 91, used for storing computer programs;

[0183] The processor 92 is used to implement the steps of the motor control method based on the flux observer as described above when storing the computer program.

[0184] For the introduction of the motor control device based on the flux observer, please refer to the above embodiment, and this application will not go into details here.

[0185] In order to solve the above technical problems, the present application also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the motor control method based on the flux observer as described above are implemented.

[0186] For an introduction to computer-readable storage media, please refer to the above embodiments, and this application will not go into details here.

[0187] It should also be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0188] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A motor control method based on a flux observer, characterized in that: include: Pre-constructing a nonlinear flux observer model, wherein the input of the nonlinear flux observer model at least includes a q-axis current; Obtaining an estimated value of the electrical angular velocity and an estimated value of the electrical angle of the motor through the nonlinear flux observer model; generating a q-axis reference current according to the electrical angular velocity estimation value and a reference angular velocity; Performing park transformation on the α-axis current and the β-axis current according to the electrical angle estimation value to obtain the d-axis actual current and the q-axis actual current; Generate a d-axis voltage and a q-axis voltage through a current loop controller according to the d-axis reference current, the d-axis actual current, the q-axis reference current, and the q-axis actual current; Park inverse transformation is performed according to the electrical angle estimation value, the d-axis voltage and the q-axis voltage to obtain the α-axis voltage and the β-axis voltage, and a PWM signal is generated according to the α-axis voltage and the β-axis voltage to control the motor.

2. The motor control method based on flux observer according to claim 1, characterized in that: The input of the nonlinear flux observer model also includes the α-axis voltage, the β-axis voltage, the α-axis current and the β-axis current.

3. The motor control method based on flux observer according to claim 2, characterized in that: Obtaining an estimated value of the electrical angular velocity and an estimated value of the electrical angle of the motor through the nonlinear flux observer model includes: Obtaining a first observation value of the rotor flux on the α-axis using an α-axis flux observer model according to the q-axis current, the α-axis current and the α-axis voltage; Obtaining a second observation value of the rotor flux on the β-axis using a β-axis flux observer model according to the q-axis current, the β-axis current and the β-axis voltage; The first observation value and the second observation value are processed by a phase-locked loop structure to obtain the electrical angle estimation value and the electrical angle estimation value.

4. The motor control method based on flux observer according to claim 3, characterized in that: Also includes: Acquire the corresponding relationship between the q-axis current and the dynamic inductance, and determine the current dynamic inductance based on the current q-axis current and the corresponding relationship; Obtaining a first observation value of the rotor flux on the α-axis using an α-axis flux observer model according to the q-axis current, the α-axis current and the α-axis voltage; Obtaining a second observation value of the rotor flux on the β-axis using a β-axis flux observer model according to the q-axis current, the β-axis current, and the β-axis voltage, includes: Obtaining a first observation value of the rotor flux on the α-axis using the α-axis flux observer model according to the current dynamic inductance, the α-axis current and the α-axis voltage; The β-axis flux observer model is used to obtain a second observation value of the rotor flux on the β-axis according to the current dynamic inductance, the β-axis current and the β-axis voltage.

5. The motor control method based on flux observer according to claim 3, characterized in that: Also includes: Negatively feeding back the first observation value to the input end of the α-axis flux observer model to perform closed-loop control on the first observation value; The second observation value is negatively fed back to the input end of the β-axis flux observer model to perform closed-loop control on the second observation value.

6. The motor control method based on flux observer according to claim 5, characterized in that: The nonlinear flux observer model is: in, is the α-axis stator flux component at time k, T is the sampling time, u sα (k) is the α-axis voltage at time k, R s is the stator resistance, i sα (k) is the α-axis current at time k, G fb is the negative feedback gain, is the first observation value at time k-1, is the α-axis stator flux component at time k-1; is the first observation value at time k, is the α-axis stator flux component at time k, is the dynamic inductance value corresponding to the q-axis current; is the second observation value at time k, is the β-axis stator flux component at time k, i sβ (k) is the β-axis current at time k, is the second observation value at time k-1, is the β-axis stator flux component at time k-1.

7. The motor control method based on flux observer according to any one of claims 3 to 6, characterized in that: Also includes: Compensating the electrical angle estimation value to obtain a compensated electrical angle estimation value; Performing a Park inverse transformation according to the electrical angle estimation value, the d-axis voltage, and the q-axis voltage to obtain an α-axis voltage and a β-axis voltage, and generating a PWM signal according to the α-axis voltage and the β-axis voltage to control the motor, including: An inverse park transformation is performed on the compensated electrical angle estimation value, the d-axis voltage and the q-axis voltage to obtain an α-axis voltage and a β-axis voltage, and a PWM signal is generated based on the α-axis voltage and the β-axis voltage to control the motor.

8. The motor control method based on flux observer according to claim 7, characterized in that: Compensating the electrical angle estimation value to obtain a compensated electrical angle estimation value includes: Obtaining a cutoff frequency of a low-pass filter in the phase-locked loop structure; Calculate the compensation angle by using a preset formula according to the cut-off frequency and the estimated value of the electrical angle; The compensation angle is superimposed on the electrical angle estimation value to obtain the compensated electrical angle estimation value.

9. The motor control method based on flux observer according to claim 8, characterized in that: The preset formula is: in, is the compensation angle, is the estimated value of the electrical angular velocity, ω comp is the cut-off frequency.

10. A motor control system based on a flux observer, characterized in that: include: A model building unit, used for pre-building a nonlinear flux observer model, wherein the input of the nonlinear flux observer model at least includes a q-axis current; An estimation unit, used for obtaining an estimated value of an electrical angular velocity and an estimated value of an electrical angle of the motor through the nonlinear flux observer model; A speed loop control unit, used for generating a q-axis reference current according to the electrical angular velocity and a reference angular velocity; A park transformation unit, configured to perform park transformation on the α-axis current and the β-axis current according to the electrical angle estimation value to obtain the d-axis actual current and the q-axis actual current; A current loop control unit, used for generating a d-axis voltage and a q-axis voltage through a current loop controller according to a d-axis reference current, the d-axis actual current, the q-axis reference current, and the q-axis actual current; A motor control unit is used to perform a Park inverse transformation according to the electrical angle estimation value, the d-axis voltage and the q-axis voltage to obtain an α-axis voltage and a β-axis voltage, and to generate a PWM signal according to the α-axis voltage and the β-axis voltage to control the motor.

11. A motor control device based on a flux observer, characterized in that: include: Memory for storing computer programs; A processor is used to implement the steps of the motor control method based on flux observer as described in any one of claims 1 to 9 when storing a computer program.

12. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the motor control method based on a flux observer are implemented as described in any one of claims 1 to 9.

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