Permanent magnet synchronous motor current harmonic disturbance suppression method and motor system

Abstract

The invention relates to the technical field of motor control, and particularly provides a permanent magnet synchronous motor current harmonic disturbance suppression method and a motor system.The permanent magnet synchronous motor current harmonic disturbance suppression method comprises the steps that firstly, a permanent magnet synchronous motor mathematical model considering harmonic disturbance under the d-q axis of a synchronous rotating coordinate system is constructed, and a theoretical basis is provided for subsequent control strategy design; an improved resonance controller is set and embedded into the extended state observer, comprehensive estimation of d-q axis non-periodic disturbance and periodic harmonic disturbance is achieved, finally, an enhanced current loop active disturbance rejection controller based on the improved resonance-extended state observer is built, unexpected peak values are eliminated, and the disturbance rejection rate of the current loop is improved. And comprehensive suppression of aperiodic disturbance and periodic disturbance is realized. According to the method, aperiodic and periodic disturbance can be suppressed, unexpected peak values are eliminated, system instability caused by noise amplification is avoided, and the steady-state performance and robustness of current control of the permanent magnet synchronous motor are remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of motor control, and particularly relates to a method for suppressing current harmonic disturbances of a permanent magnet synchronous motor and a motor system. Background Art

[0002] Due to its characteristics such as high reliability, high efficiency, and high power density, permanent magnet synchronous motors have been widely used in fields such as electric vehicles and precision equipment. However, the non-periodic disturbances and periodic harmonic disturbances faced during motor operation seriously affect the system performance and control accuracy. As a control method that does not rely on an accurate model, Active Disturbance Rejection Control (ADRC) shows broad application prospects in the control of permanent magnet synchronous motors with its high-efficiency estimation and compensation capabilities for system disturbances. Among them, the Extended State Observer (ESO) is the core component of ADRC, which can estimate the state and disturbances of the system, thereby effectively improving the anti-interference performance of the system. However, due to limited bandwidth, traditional ESO is difficult to simultaneously achieve accurate estimation of disturbances and effective suppression of measurement noise, which limits the further improvement of system performance. In addition, the ADRC algorithm based on traditional resonance will also cause unwanted peak problems, amplifying the noise in this frequency band, thus affecting the stability of the system. Summary of the Invention

[0003] In view of this, the present invention aims to provide a method for suppressing current harmonic disturbances of a permanent magnet synchronous motor, designs an improved resonance controller, and embeds the improved resonance controller into the extended state observer for disturbance estimation, effectively suppressing the non-periodic disturbances and periodic harmonic disturbances during motor operation, eliminating unwanted peaks, and improving the performance of the motor system.

[0004] To achieve the above object, the technical solution of the present invention is realized as follows: On the one hand, the present invention provides a method for suppressing current harmonic disturbances of a permanent magnet synchronous motor, including: Construct a mathematical model of the current loop of the permanent magnet synchronous motor considering the total disturbance, and define the total disturbance on the d-q axis as the extended state of the motor system; the mathematical model of the current loop of the permanent magnet synchronous motor considering the total disturbance is: ; Wherein, represents time, represents the d-axis stator current, represents the q-axis stator current, represents the current control gain, , represents the nominal value of the inductance of the motor, denotes the d-axis stator reference voltage denotes the q-axis stator reference voltage denotes the known disturbance on the d-axis denotes the known disturbance on the q-axis denotes the total disturbance on the d-axis denotes the total disturbance on the q-axis; Design an improved resonant controller, an improved resonant controller for any frequency harmonic is: ; wherein, denotes the resonant gain denotes the resonant bandwidth denotes the resonant frequency , denotes the Laplace complex frequency variable denotes the bandwidth of the extended state observer; And embed the improved resonant controller into the extended state observer to estimate the total disturbance; Introduce the total disturbance estimation as a feedforward signal into the control end, and design a control law to compensate for the total disturbance in the mathematical model of the permanent magnet synchronous motor current loop.

[0005] Preferably, the total disturbance includes: aperiodic disturbance and periodic harmonic disturbance.

[0006] Preferably, the calculation formula for the harmonic disturbance of the d-q axes of the current loop is: ; wherein, , denotes the harmonic disturbance of the d-q axes denotes the harmonic disturbance of the d-axis denotes the harmonic disturbance of the q-axis , denotes the d-q axis voltage harmonics caused by the inverter dead-time effect denotes the d-axis voltage harmonics caused by the inverter dead-time effect denotes the q-axis voltage harmonics caused by the inverter dead-time effect , denotes the permanent magnet flux harmonics under the d-q axes denotes the d-axis flux harmonics denotes the q-axis flux harmonics , denotes the number of pole pairs of the motor is the mechanical angular velocity of the motor , denotes the d-axis inductance and the nominal value of the d-axis inductance The error of , represents the q-axis inductance and the nominal value of the q-axis inductance The error of, the surface-mounted permanent magnet synchronous motor satisfies ; The calculation formula for the non-periodic disturbance of the d-q axis of the current loop is: ; Among them, represents the d-axis non-periodic disturbance, represents the q-axis non-periodic disturbance, , represents the stator resistance and the nominal value of the resistance The error of, represents the d-axis uncertainty disturbance, represents the q-axis uncertainty disturbance.

[0007] Preferably, the total d-q axis disturbance is defined as the extended state of the motor system, and the extended state system is obtained as: ; ; Among them, is the derivative of the total d-axis disturbance, is the derivative of the total q-axis disturbance.

[0008] Preferably, when suppressing multi-frequency harmonic disturbances, the improved resonant controller The expression of is: ; Among them, represents the resonant gain of different frequencies, represents the resonant bandwidth of different frequencies, represents the resonant frequency of different frequencies.

[0009] Preferably, to suppress the 6th harmonic disturbance and the 12th harmonic disturbance, , .

[0010] Preferably, the improved resonant controller is embedded in the extended state observer to obtain the improved resonant-extended state observer for the d-axis and q-axis as: ; ; Among them, represents the estimated d-axis stator current, represents the estimated q-axis stator current, Represents the total d-axis disturbance estimation, Represents the total q-axis disturbance estimation, Represents the aperiodic d-axis disturbance estimation, Represents the aperiodic q-axis disturbance estimation, Represents the harmonic d-axis disturbance estimation, Represents the harmonic q-axis disturbance estimation, 、 、 and are the state variables of the improved resonant controller, and are the gain coefficients of the extended state observer, and represent intermediate variables.

[0011] Preferably, the control law is: ; wherein, represents the d-axis stator reference voltage, represents the q-axis stator reference voltage, represents the d-axis reference current, represents the q-axis reference current, is a constant for compensating the known d-axis disturbance, is a constant for compensating the known q-axis disturbance, , represents the d-axis current loop controller gain, , represents the q-axis current loop controller gain.

[0012] On the other hand, the present invention provides a motor system adopting the method for suppressing current harmonic disturbance of a permanent magnet synchronous motor.

[0013] Compared with the prior art, the present invention can achieve the following beneficial effects: By constructing an extended state observer containing an improved resonant controller, the present invention realizes the estimation and suppression of aperiodic and harmonic disturbances on the d-q axes. By optimizing the resonant characteristics and the observer structure, while enhancing the ability to suppress harmonic disturbances, the undesired peaks near the resonant frequency are effectively eliminated. Compared with the traditional active disturbance rejection control and the traditional resonant active disturbance rejection control, the present invention has obvious effect on current harmonic suppression, avoids the risk of amplifying noise and affecting system stability near the resonant frequency, and thus significantly improves the harmonic suppression ability and operation smoothness of the system.

[0014] The present invention can effectively resist the adverse effects brought by parameter changes under complex working conditions, ensure that the system has strong anti-disturbance performance and reliability, and can maintain excellent control performance under system parameter changes. Compared with the traditional control method, the enhanced active disturbance rejection control method of the present invention has significant advantages in aspects such as harmonic suppression, system stability, and parameter robustness. Description of the Drawings

[0015] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 is the structural block diagram of a permanent magnet synchronous motor control system applying the permanent magnet synchronous motor current harmonic disturbance suppression method provided by the embodiment of the present invention; Figure 2 is the permanent magnet synchronous motor current harmonic disturbance suppression method provided by the embodiment of the present invention; Figure 3 is the structural block diagram of the enhanced active disturbance rejection control based on an improved resonant-extended state observer provided by the embodiment of the present invention; Figure 4 is different according to the embodiment of the present invention Bode diagrams of traditional resonant controllers under; Figure 5 is different according to the embodiment of the present invention Bode diagrams of traditional resonant controllers under; Figure 6 is different according to the embodiment of the present invention Bode diagrams of improved resonant controllers under; Figure 7 is different according to the embodiment of the present invention Bode diagrams of improved resonant controllers under; Figure 8 is the Bode diagram of the interference estimation error and the actual interference transfer function under different observers provided by the embodiment of the present invention; Figure 9 is the Bode diagram of the closed-loop system output and the actual interference transfer function under different active disturbance rejection algorithms provided by the embodiment of the present invention; Figure 10 is the d-q axis and phase current waveform diagrams of traditional active disturbance rejection control under a rotational speed of 150 r / min and a load of 3 N·m provided by the embodiment of the present invention; Figure 11 is the d-q axis and phase current waveform diagrams of traditional resonant active disturbance rejection control under a rotational speed of 150 r / min and a load of 3 N·m provided by the embodiment of the present invention; Figure 12 It is the d-q axis and phase current waveform diagrams of enhanced active disturbance rejection control at a rotational speed of 150 r / min and a load of 3 N·m according to an embodiment of the present invention; Figure 13 It is the d-q axis current waveform diagrams of inductance mismatch at a rotational speed of 150 r / min and a load of 6 N·m according to an embodiment of the present invention; Figure 14 It is the d-q axis current waveform diagrams of resistance mismatch at a rotational speed of 150 r / min and a load of 6 N·m according to an embodiment of the present invention; Figure 15 It is the d-q axis current waveform diagrams of flux linkage mismatch at a rotational speed of 150 r / min and a load of 6 N·m according to an embodiment of the present invention. Detailed implementation manners

[0016] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. Similar elements in different embodiments are labeled with related similar element numbers. In the following embodiments, many details are described to enable a better understanding of the present invention. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, or methods. In some cases, some operations related to the present invention are not shown or described in the specification to avoid the core part of the present invention being overwhelmed by excessive description. For those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0017] It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other to form various embodiments. At the same time, the steps or actions in the method description can also be reordered or adjusted in an obvious manner by those skilled in the art. Therefore, the various sequences in the specification and drawings are only for clearly describing a certain embodiment, and do not mean that they are the necessary sequences, unless it is stated that a certain sequence must be followed.

[0018] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, terms such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality of" is two or more.

[0019] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific circumstances.

[0020] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0021] In one embodiment of the present invention, a method for suppressing current harmonic disturbances of a permanent magnet synchronous motor based on enhanced active disturbance rejection is provided. This method is specifically applied to a permanent magnet synchronous motor system as shown in Figure 1 to estimate and compensate for periodic harmonic disturbances and aperiodic disturbances. The permanent magnet synchronous motor system adopts a cascaded double closed-loop structure including a speed loop and a current loop. Specifically, the speed loop is adjusted by a PI controller to output the reference current of the q-axis; the current loop is adjusted by the invented control scheme to output the reference voltages of the d-axis and the q-axis. In addition, the designed harmonic suppression link with multiple frequency selection characteristics is integrated into the extended state observer to jointly form an enhanced active disturbance rejection control framework with the control law. Among them, the integral link in the observer is used to estimate aperiodic disturbances, and the introduced harmonic suppression link is used to accurately estimate multiple harmonic disturbances.

[0022] Among them, the speed command , which is the speed value that the motor is expected to reach and serves as the input target of the entire control system.

[0023] A position / speed sensor, which is used to obtain the actual speed of the motor, perform closed-loop feedback control on the actual speed, so that the system can correct the speed deviation in real time and improve the control accuracy.

[0024] A PI speed regulator, which is used to receive the speed error obtained by comparing the actual speed with the speed command, and process the error through proportional (P) and integral (I) operations, so that the system can accurately track the speed command at steady state.

[0025] d-axis current command , which is used to control the magnetic flux of the motor.

[0026] q-axis current command , which is used to adjust the motor torque.

[0027] d-axis enhanced active disturbance rejection controller and q-axis enhanced active disturbance rejection controller, which are respectively used to control the d-axis and q-axis currents, suppress various disturbances in the system, such as the influence of load changes, motor parameter changes, etc. on current control. According to the reference value and feedback value of the current, output the corresponding d-axis and q-axis voltage commands and , so that the actual current can accurately track the command current and ensure the stable operation of the motor.

[0028] abc / dq transformation, which is used to convert the current feedback value in the three-phase stationary coordinate system (abc) into the current value in the two-phase rotating coordinate system (dq).

[0029] dq / transformation, which is used to convert signals between different control links.

[0030] SVPWM (Space Vector Pulse Width Modulation), which is used to receive the voltage commands in the coordinate system and , and calculate the signals for controlling the inverter switching tubes through a specific algorithm.

[0031] An inverter, which consists of multiple power switching tubes, converts direct current into three-phase alternating current according to the switching signals output by the SVPWM module, and is used to drive the three-phase windings of the permanent magnet synchronous motor, so that the motor can rotate normally.

[0032] Current sampling, which is used to sample the three-phase alternating current in real time during the operation of the motor, obtain the actual operating current information of the motor, and feedback the current information to the control system for comparison with the current command to form current closed-loop control.

[0033] For the current harmonic disturbance of the above system, the present invention proposes a method for suppressing the current harmonic disturbance of a permanent magnet synchronous motor as shown in Figure 2 The specific steps are as follows: S1: First, establish the stator current equation of the permanent magnet synchronous motor and express it as: (1) Where, represents time, represents the d-axis stator current, represents the q-axis stator current, represents the d-axis inductance, represents the q-axis inductance. Since the d- and q-axis inductances of the surface-mounted permanent magnet synchronous motor are the same, they can be uniformly represented by , that is , represents the stator resistance, represents the number of pole pairs of the motor, represents the mechanical angular velocity of the motor, represents the permanent magnet flux linkage.

[0034] Based on the stator current equation of the permanent magnet synchronous motor, analyze and calculate the harmonic sources in the motor system, and calculate the periodic current harmonics introduced by various factors, specifically including: Since the permanent magnets of the permanent magnet synchronous motor are not perfect ideal magnets, there may be certain non-uniformities in their magnetic field distribution, or during the operation of the motor, due to the influence of factors such as armature reaction, flux harmonics are generated on the d-q axes. Therefore, according to the above stator current equation (1), deduce and calculate the harmonics of the flux in the d-axis and q-axis directions, and obtain the permanent magnet flux harmonics under the d-q axes as: (2) Where, represents the d-axis flux harmonic, represents the q-axis flux harmonic, represents the amplitude of the 6kth harmonic of the d-axis, represents the amplitude of the 6kth harmonic of the q-axis, k is an integer, and the 6kth harmonic means that the frequency of the harmonic is 6k times the fundamental frequency.

[0035] In the inverter, in order to prevent the switching tubes of the upper and lower bridge arms from conducting simultaneously and causing a short circuit, a dead time is set. However, the existence of the dead time will cause a difference between the PWM waveform output by the inverter and the ideal waveform, thus generating voltage harmonics. The voltage harmonics caused by the dead time effect of the inverter can be expressed as: (3) Where, represents the d-axis voltage harmonic, q-axis voltage harmonic, Denotes the dead time, Denotes the sampling period, Denotes the DC voltage.

[0036] Define the harmonic disturbance of the current loop on the d-q axis as: (4) Wherein, , Denotes the harmonic disturbance of the d-q axis, Denotes the harmonic disturbance of the d axis, Denotes the harmonic disturbance of the q axis, , Denotes the voltage harmonics of the d-q axis caused by the dead-time effect of the inverter, Denotes the voltage harmonics of the d axis caused by the dead-time effect of the inverter, Denotes the voltage harmonics of the q axis caused by the dead-time effect of the inverter, , Denotes the permanent magnet flux harmonics under the d-q axis, Denotes the d-axis flux harmonics, Denotes the q-axis flux harmonics, , Denotes the number of pole pairs of the motor, Is the mechanical angular velocity of the motor, , Denotes the d-axis inductance And the nominal value of the d-axis inductance Error, , Denotes the q-axis inductance And the nominal value of the q-axis inductance Error, .

[0037] Due to the uncertainty and time-variation of system parameters, the current loop will also be affected by non-periodic disturbances on the d-q axis. In the embodiments of the present invention, the non-periodic disturbance of the current loop on the d-q axis is defined as: (5) Wherein, Denotes the non-periodic disturbance of the d axis, Denotes the non-periodic disturbance of the q axis, , Denotes the stator resistance And the nominal value of the resistance Error, , , , And Respectively denote the nominal values of the d-axis and q-axis inductances, , Represents the motor flux linkage And the nominal value of the flux linkage Of the error, Represents the d-axis uncertainty disturbance, Represents the q-axis uncertainty disturbance.

[0038] Based on the above factors, the d-axis disturbance can be obtained as: ; The q-axis disturbance is: . In addition, in the control system, there will be non-linear behaviors such as saturation operation of the amplitude limit, which will cause the mismatch between the d-axis and q-axis voltages, thus causing non-periodic disturbances. Therefore, on the basis of And , it is also necessary to further consider the non-periodic disturbances introduced by the voltage mismatch. After considering the total disturbances composed of periodic harmonic disturbances and non-periodic disturbances, the mathematical model of the permanent magnet synchronous motor current loop can be rewritten as: (6) Among them, Represents the current control gain, , Represents the d-axis stator reference voltage, Represents the q-axis stator reference voltage, Represents the known disturbance of the d-axis, , Represents the known disturbance of the q-axis , Represents on On the basis of further considering the total d-axis disturbance of the voltage mismatch, , Represents on On the basis of further considering the total q-axis disturbance of the voltage mismatch, .

[0039] For the convenience of subsequent design of the extended state observer, the total d-q axis disturbance is defined as the extended state of the motor system, that is, as one of the state variables, and then the extended state observer is used to estimate the total disturbance in real time, so as to compensate for the total disturbance in the control strategy. After defining the total d-q axis disturbance as the extended state of the motor system, the obtained extended state system is: (7) (8) Among them, And Are assumed to be differentiable, Is the derivative of the total d-axis disturbance, Is the derivative of the total q-axis disturbance.

[0040] S2: It should be particularly noted that although increasing the bandwidth of the traditional extended state observer can significantly enhance its ability to observe disturbances, it will inevitably amplify noise and reduce the robustness of the system. In addition, the extended state observer based on the traditional resonance characteristic (TRSC-ESO) has significant advantages in enhancing the ability to observe harmonic disturbances. However, this method often introduces an undesired peak phenomenon near the resonance frequency, thus amplifying the noise in this frequency band and even causing system instability. Therefore, the purpose of the present invention is to design an extended state observer based on improved resonance (IRSC) (IRSC-ESO), which can effectively eliminate the undesired peak near the resonance frequency while enhancing the ability to suppress harmonic disturbances by optimizing the resonance characteristic and the observer structure.

[0041] In the embodiment of the present invention, in order to achieve the comprehensive suppression of aperiodic disturbances and periodic harmonic disturbances while avoiding the problem of undesired peaks, an improved resonance controller (IRSC) is designed for any frequency harmonic. It is: (9) Wherein, represents the resonance gain, represents the resonance bandwidth, represents the resonance frequency, , represents the Laplace complex frequency variable, represents the bandwidth of the extended state observer.

[0042] Due to the existence of multiple harmonic disturbances, in order to effectively suppress multiple harmonic disturbances, it is necessary to generalize the function of the improved resonance controller so that it has the ability to suppress harmonic disturbances of multiple frequencies. Therefore, on the basis of formula (9), when suppressing multiple-frequency harmonic disturbances, the improved resonance controller based on multiple frequencies is extended and generalized. Its expression is: (10) Wherein, represents the resonance gains of different frequencies, represents the resonance bandwidths of different frequencies, represents the resonance frequencies of different frequencies.

[0043] Considering that the harmonic amplitude decreases with the increase of the harmonic order, only the influence of the 6th and 12th harmonic disturbances is considered. For the 6th and 12th harmonic disturbances, an improved resonance controller is designed. It is: (11) Wherein, , .

[0044] For the permanent magnet synchronous motor current loop mathematical model expressed by Equation (6), an extended state observer is designed, and an improved resonant controller is embedded in the extended state observer to obtain the improved resonant-extended state observer for the d-axis and q-axis as follows: (12) (13) Wherein, represents the estimated d-axis stator current, represents the estimated q-axis stator current, represents the estimated total disturbance of the d-axis, represents the estimated total disturbance of the q-axis, represents the estimated non-periodic disturbance of the d-axis, represents the estimated non-periodic disturbance of the q-axis, represents the estimated harmonic disturbance of the d-axis, represents the estimated harmonic disturbance of the q-axis, 、 、 and are the state variables of the improved resonant controller, and are the gain coefficients of the extended state observer, and represent intermediate variables.

[0045] Furthermore, according to the pole placement strategy, the gain coefficients of the nth-order extended state observer whose characteristic equation satisfies are: (14) Wherein, , is defined as the observer bandwidth. Therefore, the gain coefficients of the extended state observer based on the improved resonance can be deduced as .

[0046] S3: As shown in Figure 3 , the total disturbance obtained by the resonant-extended state observer in S2 is introduced as a feedforward signal into the control end, and a reasonable control law is designed to achieve enhanced active disturbance rejection control based on the improved resonant-extended state observer, and the observed disturbance signal is accurately suppressed and eliminated, thereby further enhancing the control accuracy and robustness of the system. Specifically, from the d-axis reference current and the q-axis reference current , define , , then we can get: (15) With proportional control, the error convergence control law can be expressed as: (16) where and are the d-axis and q-axis current loop controller gains respectively.

[0047] Substituting Equation (16) into Equation (15), we can obtain: (17) In Equation (17), the total disturbance is unknown and is usually replaced by the observed value. Additionally, to reduce the influence of measurement noise, the current estimated by the observer is used instead of the actual current. Thus, the control law can be rewritten as: (18) where , , 、 is the total disturbance estimation obtained by observing S2, which can achieve the compensation of unknown disturbances. Refer to differential feedforward 、 is used to reduce the oscillation and overshoot in the system dynamic process, and at the same time significantly shorten the adjustment time of the system.

[0048] If all disturbances can be accurately compensated, the d-q axis system can be simplified to an integrator, that is: (19) Furthermore, to verify the superiority of the improved resonant-extended state observer, the present invention conducts a comparative experiment on the traditional resonant controller (ESO), the extended state observer based on the traditional resonance (TRSC-ESO), and the resonant-extended state observer based on the improved resonance (IRSC-ESO), and obtains the following results: Figure 4 and Figure 5 respectively show when changing from 2 rad / s to 30 rad / s, when changing from 10 to 120, the Bode plots of the traditional quasi-resonant controller, where the abscissa is the frequency (Frequency) with the unit of rad / s, and the ordinate is the harmonic amplitude value (Magnitude) with the unit of dB.

[0049] Figure 6 and Figure 7 respectively show when changing from 2 rad / s to 30 rad / s, when changing from 10 to 120, the Bode plots of the improved resonant controller, with the bandwidth is 100 rad / s, where the abscissa is the frequency, with the unit of rad / s, and the ordinate is the harmonic amplitude value (Magnitude), with the unit of dB.

[0050] From Figures 4 - 7 it can be seen that both the improved resonant controller and the traditional quasi-resonant controller exhibit significant amplitude peaks at the resonant frequency, and this characteristic plays a key role in suppressing the harmonic disturbance of the target frequency. In addition, by increasing the parameters of the two controllers, the resonant bandwidth can be significantly broadened, thereby enhancing the robustness of the system to the change of the resonant frequency; while increasing the resonant gain further strengthens the suppression performance of the two controllers at the target resonant frequency, thus effectively enhancing the harmonic suppression effect of the system. However, there are obvious differences in the amplitude-frequency response characteristics of the two controllers outside the resonant frequency: the traditional quasi-resonant controller shows a typical amplitude-frequency attenuation characteristic of -20 dB / dec outside the resonant frequency, while the improved resonant controller can maintain an amplitude-frequency response of 0 dB outside the resonant frequency.

[0051] Furthermore, to illustrate and verify the superiority of using the improved resonant-extended state observer to estimate and compensate for the total disturbance, the mathematical model of the permanent magnet synchronous motor current loop considering the total disturbance and the resonant-extended state observer are analyzed. When it is the case, the transfer function between the disturbance estimation error of the traditional extended state observer and the actual disturbance can be obtained as follows: (20) where, represents the actual disturbance signal, represents the disturbance estimation obtained by the traditional extended state observer, , .

[0052] Similarly, the transfer function between the disturbance estimation error of the traditional resonant extended state observer and the actual disturbance can be derived as follows: (21) where, represents the actual disturbance signal, represents the disturbance estimation obtained based on the traditional resonant-extended state observer, , .

[0053] The transfer function between the disturbance estimation error of the improved resonant-extended state observer and the actual disturbance is as follows: (22) Among them, represents the actual disturbance signal, represents the total disturbance estimation obtained by the improved resonance-extended state observer, .

[0054] Thus, the Bode plots of , and can be plotted as shown in Figure 8 . Among them, the bandwidth is 100 rad / s, the resonance bandwidth , the resonance frequencies , are 400 rad / s and 1000 rad / s respectively, the resonance gain of TRSCs, the resonance gain of IRSCs .

[0055] Figure 8 From Figure 8 it can be seen that the amplitude-frequency characteristics and phase-frequency characteristics of ESO, TRSC-ESO, and IRSC-ESO are less different in the low-frequency and high-frequency bands, indicating that the three have similar performance in these frequency bands. In addition, both TRSC-ESO and IRSC-ESO show significant amplitude attenuation at the resonance frequency. This large amplitude attenuation characteristic enables the observer to accurately estimate the harmonic interference of the same frequency and at the same time demonstrates excellent frequency selectivity. However, from Figure 8 it can also be found that there is an undesired peak phenomenon near the resonance frequency in the traditional resonance-based extended state observer, that is, the amplitude-frequency response exceeds 0 dB in part of the frequency range. Compared with the traditional extended state observer, this peak phenomenon will amplify the interference estimation error, thereby reducing the estimation effect on the actual interference, and thus affecting the performance of the observer in practical applications. In contrast, the improved resonance-based extended state observer successfully eliminates the undesired peak phenomenon near the resonance frequency through optimized design. In addition, it requires a lower resonance gain to achieve the same harmonic suppression performance. To sum up, under the same bandwidth condition, the invented improved resonance-based extended state observer not only effectively eliminates the negative impact of the undesired peak in the traditional resonance observer, but also shows stronger harmonic suppression performance and superior control performance.

[0056] Furthermore, to illustrate and verify the progressiveness of the enhanced active disturbance rejection control (EADRC) based on the improved resonance-extended state observer, a comparative analysis of the traditional active disturbance rejection control (ADRC) based on the extended state observer, the improved active disturbance rejection control (IADRC) based on the traditional resonance-extended state observer, and the enhanced active disturbance rejection control (EADRC) based on the improved resonance-extended state observer is carried out as follows: Based on the mathematical model of the current loop of a permanent magnet synchronous motor considering the total disturbance, the resonant-extended state observer, and the control law, when the transfer function of the output of the ADRC under the action of the disturbance can be obtained as: (23) Similarly, the closed-loop system output transfer function of the IADRC under the action of the disturbance can be derived as: (24) The closed-loop system output transfer function of the EADRC under the action of the disturbance is derived as: (25) Plot the , and Bode plots as Figure 9 shown. Among them, the bandwidth is 100 rad / s, the resonant bandwidth , the resonant frequencies , are 400 rad / s and 1000 rad / s respectively, the resonant gain of the TRSCs, and the resonant gain of the IRSCs. From the Figure 9 frequency-domain characteristic analysis results, it can be seen that the three active disturbance rejection controllers have similar performance in the low-frequency and high-frequency ranges. In addition, both the IADRC and the EADRC exhibit significant amplitude attenuation characteristics at the resonant frequency, which gives them significant advantages in suppressing harmonic interference. It should be noted that the EADRC does not have the problem of unexpected peaks near the resonant frequency, which can improve the stability of the closed-loop system.

[0057] Figure 10 are the d-q axis and phase current waveform diagrams of the permanent magnet synchronous motor under the traditional active disturbance rejection control at the operating conditions of 150 r / min and 3 N·m, where , . It can be seen that the peak value of the q-axis current ripple of the traditional active disturbance rejection control is 0.625 A, the peak value of the d-axis current ripple is 0.336 A, and the total harmonic distortion of the q-axis current is 7.12%. Among them, the abscissa is the frequency (Frequency) with the unit of Hz, and the ordinate is the current amplitude with the unit of A.

[0058] Figure 11 are the d-q axis and phase current waveform diagrams of the permanent magnet synchronous motor under the traditional resonant active disturbance rejection control at the operating conditions of 150 r / min and 3 N·m, where , , , , , , It can be clearly seen that the peak value of the q-axis current ripple of the traditional resonant active disturbance rejection control is 0.346 A, the peak value of the d-axis current ripple is 0.252 A, and the total harmonic distortion of the q-axis current is 2.57%. This shows that the traditional resonant active disturbance rejection control has good harmonic suppression ability. However, through fast Fourier transform (FFT) analysis, it can be found that the traditional resonant active disturbance rejection control introduces an undesired peak amplification effect near the resonant frequency, especially the amplification of the 15th and 18th harmonics is more significant. This peak effect will not only increase the high-order harmonics, but also amplify the influence of noise, resulting in a decrease in system stability, thus restricting the performance optimization of the control system.

[0059] Figure 12 Fig. is the waveforms of the d-q axis and phase currents of the permanent magnet synchronous motor under the enhanced active disturbance rejection control at the working conditions of 150 r / min and 3 N·m, where , , , , It can be clearly seen that the peak value of the q-axis current ripple of the enhanced active disturbance rejection control is 0.187 A, the peak value of the d-axis current ripple is 0.125 A, and the total harmonic distortion of the q-axis current is 1.64%. By comparison Figure 10 it can be found that the invented enhanced active disturbance rejection control method shows significant advantages in suppressing periodic harmonics, effectively reducing the influence of harmonics on the system performance. Further comparison Figure 11 shows that, compared with the traditional resonant active disturbance rejection control, the enhanced active disturbance rejection control requires a smaller resonant gain. Although the gain is smaller, the enhanced active disturbance rejection control still performs more superiorly than the traditional resonant active disturbance rejection control in harmonic suppression, and effectively overcomes the common undesired peak problem in the traditional control method. Specifically, the enhanced active disturbance rejection control can suppress the target harmonics while avoiding amplifying the harmonics and noise at the nearby frequencies, thus significantly improving the system stability. In addition, due to the larger bandwidth design, the enhanced active disturbance rejection control also reduces the amplitudes of the 15th and 18th high-order harmonics. This characteristic further improves the quality of the motor current, reduces the interference of harmonics on the smooth operation of the motor, and thus provides better guarantee for the high-performance operation of the system.

[0060] Figure 13This is the waveform diagram of the d-axis and q-axis currents of a permanent magnet synchronous motor under the conditions of 150 rad / s and 6 N·m when the inductance changes. It can be clearly observed that when the d-axis and q-axis inductances are mismatched simultaneously, the d-axis current of the system shows obvious fluctuations. However, thanks to the excellent disturbance rejection ability of the controller, this kind of fluctuation can quickly decay and return to the steady state. In addition, from the analysis of the total harmonic distortion (THD) of the current, it can be seen that the THD before and after the change of the inductance parameters remains basically the same, indicating that the system performance is not significantly affected. The dynamic behaviors of the system under similar resistance and flux linkage mismatches are also verified respectively in Figure 14 and Figure 15 . These results comprehensively show that the designed control strategy can effectively resist the adverse effects brought by parameter changes under complex working conditions, ensuring that the system has strong anti-disturbance performance and reliability.

[0061] Therefore, the invented enhanced active disturbance rejection control shows stronger harmonic suppression ability compared with the traditional active disturbance rejection control and the traditional resonant active disturbance rejection control, and successfully solves the problem of unexpected peaks existing in the traditional resonant active disturbance rejection control algorithm. In addition, this method also shows strong parameter robustness and can still maintain excellent control performance under the change of system parameters.

[0062] In conclusion, the above is only the preferred embodiment of this specification and is not used to limit the protection scope of this specification. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this specification shall be included within the protection scope of this specification.

[0063] The system, device, module or unit illustrated in one or more of the above embodiments can be specifically implemented by a computer chip or entity, or by a product with certain functions. A typical implementation device is a computer. Specifically, the computer can be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or any combination of these devices.

[0064] It should also be noted that the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to this process, method, commodity or device. Without more limitations, the element defined by the statement "including one..." does not exclude the existence of another identical element in the process, method, commodity or device including the said element.

[0065] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other, and the differences between each embodiment and other embodiments are emphasized. In particular, for system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and for related parts, reference can be made to the partial description of the method embodiments.

[0066] The above describes specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in a different order than in the embodiments and still achieve the desired result. Additionally, the processes depicted in the figures do not necessarily require the particular order or sequential order shown to achieve the desired result. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

Claims

1. A method for suppressing current harmonic disturbance of a permanent magnet synchronous motor, characterized in that: include: A mathematical model of the permanent magnet synchronous motor current loop considering the total disturbance is constructed, and the total disturbance of the dq axis is defined as the expansion state of the motor system; the mathematical model of the permanent magnet synchronous motor current loop considering the total disturbance is: ； in, Indicates time, represents the d-axis stator current, represents the q-axis stator current, represents the current control gain, , Indicates the nominal value of the motor’s inductance, represents the d-axis stator reference voltage, represents the q-axis stator reference voltage, represents the known perturbation of the d-axis, represents a known disturbance on the q-axis, represents the total disturbance on the d-axis, represents the total disturbance on the q-axis; Design an improved resonant controller for any frequency harmonic for: ； in, represents the resonant gain, represents the resonant bandwidth, represents the resonant frequency, , represents the Laplace complex frequency variable, represents the bandwidth of the extended state observer; and embedding the improved resonant controller into an extended state observer to estimate the total disturbance; The total disturbance estimation is introduced into the control end as a feedforward signal, and the control law is designed to compensate the total disturbance in the mathematical model of the permanent magnet synchronous motor current loop.

2. The method for suppressing current harmonic disturbance of a permanent magnet synchronous motor according to claim 1, characterized in that: The total disturbance includes: non-periodic disturbance and periodic harmonic disturbance.

3. The method for suppressing current harmonic disturbance of a permanent magnet synchronous motor according to claim 2, characterized in that: The calculation formula for the harmonic disturbance of the current loop dq axis is: ； in, , represents the harmonic disturbance of the dq axis, represents the harmonic disturbance of the d-axis, represents the harmonic disturbance of the q-axis, , It represents the dq axis voltage harmonics caused by the inverter dead zone effect, represents the d-axis voltage harmonics caused by the inverter dead-time effect, represents the q-axis voltage harmonics caused by the inverter dead-time effect, , represents the permanent magnet flux harmonics under the dq axis, represents the d-axis flux harmonic, represents the q-axis flux harmonic, , Indicates the number of pole pairs of the motor, is the mechanical angular velocity of the motor, , Indicates the d-axis inductance With the nominal value of d-axis inductance The error, , Indicates the q-axis inductance and the nominal value of the q-axis inductance The surface-mounted permanent magnet synchronous motor meets the error of ; The calculation formula for the non-periodic disturbance of the dq axis of the current loop is: ； in, represents the non-periodic disturbance of the d-axis of the current loop, represents the non-periodic disturbance of the q-axis of the current loop, , Indicates stator resistance With the nominal value of resistance The error, Indicates the motor flux With the nominal value of magnetic flux The error, represents the d-axis uncertainty disturbance, represents the q-axis uncertainty disturbance.

4. The method for suppressing current harmonic disturbance of a permanent magnet synchronous motor according to claim 3, characterized in that: The total disturbance of the dq axis is defined as the expanded state of the motor system, and the expanded state system is obtained as: ； ； in, is the derivative of the total disturbance about the d-axis, is the derivative of the total disturbance about the q axis.

5. The method for suppressing current harmonic disturbance of a permanent magnet synchronous motor according to claim 3, characterized in that: Improved resonant controller for suppressing multi-frequency harmonic disturbances The expression is: ； in, Represents the resonance gain at different frequencies, Represents the resonance bandwidth of different frequencies, Indicates the resonant frequencies of different frequencies.

6. The method for suppressing current harmonic disturbance of a permanent magnet synchronous motor according to claim 5, characterized in that: Suppress the 6th and 12th harmonic disturbances. , .

7. The method for suppressing current harmonic disturbance of a permanent magnet synchronous motor according to claim 6, characterized in that: The improved resonant controller is embedded in the extended state observer to obtain the improved resonant-extended state observer of the d-axis and q-axis: ； ； in, represents the d-axis stator current estimate, represents the q-axis stator current estimate, represents the total disturbance estimate of the d-axis, represents the total disturbance estimate of the q-axis, represents the d-axis non-periodic perturbation estimate, represents the q-axis non-periodic disturbance estimate, represents the d-axis harmonic disturbance estimate, represents the q-axis harmonic disturbance estimate, , , and is the state variable of the improved resonant controller, and is the gain coefficient of the extended state observer, and is an intermediate variable.

8. The method for suppressing current harmonic disturbance of a permanent magnet synchronous motor according to claim 7, characterized in that: The control law is: ； in, represents the d-axis stator reference voltage, represents the q-axis stator reference voltage, represents the d-axis reference current, represents the q-axis reference current, is a constant used to compensate for known disturbances in the d-axis. is a constant used to compensate for known disturbances in the q axis. , represents the d-axis current loop controller gain, , Represents the q-axis current loop controller gain.

9. A motor system, characterized in that: A method for suppressing current harmonic disturbances of a permanent magnet synchronous motor as described in any one of claims 1 to 8 is adopted.

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