Permanent magnet synchronous motor current harmonic suppression method, device and system

Abstract

The invention belongs to the technical field of permanent magnet synchronous motors, and discloses a current harmonic suppression method, device and system for a permanent magnet synchronous motor, and the method comprises the following steps: converting a three-phase stator current into a d-axis current and a q-axis current under a d-q synchronous rotating coordinate system according to a current harmonic model of the permanent magnet synchronous motor; d-axis current and q-axis current are calculated, d-axis voltage and q-axis voltage are calculated, the d-axis current, the q-axis current, the d-axis voltage and the q-axis voltage are injected into the resonance-cascade expansion state observer, and an estimated value and a compensation voltage value of input current are obtained; and injecting the generated compensation voltage value into a vector control current inner ring of the permanent magnet synchronous motor, and adding the compensation voltage value with the d-axis voltage and the q-axis voltage. According to the method, the dynamic performance and the steady-state performance of the system can be improved, the accuracy of the generated compensation voltage can be ensured, the influence of the performance defect of the observer on the current harmonic suppression effect is reduced, and the error of current harmonic tracking is reduced on the premise of ensuring the rapidity.

Description

Technical Field

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

[0002] Interior Permanent Magnet Synchronous Motors (IPMSMs) have the advantages of high power density, high efficiency, good speed regulation performance, and compact structure, and are widely used in the fields of high-end equipment manufacturing and household appliances. In the IPMSM control system, due to the non-linear characteristics of the inverter such as dead time and tube voltage drop, time harmonics will be introduced into the stator current. At the same time, the cogging effect and magnetic saturation effect will introduce space harmonics into the stator current. For space harmonics, the main suppression method is to optimize the motor body structure; for time harmonics, the main suppression method is to optimize the motor control method. At present, the extended state observer has been applied in motor control due to its simple mathematical model and strong stability. However, when the extended state observer tracks current harmonics, due to the defects of the steady-state performance and dynamic performance of the observer, and its lack of the ability to suppress current harmonics itself, the error of current harmonic tracking is relatively large.

[0003] The Chinese patent publication number is CN113965129B, and the authorized patent with the name of a compensation method for suppressing current harmonics of a permanent magnet synchronous motor control system considering dynamic and steady-state performance includes: establishing a permanent magnet synchronous motor vector control system including phase current measurement offset error; deriving the primary pulsation equation of the motor steady-state speed caused by the phase current measurement offset error; designing a resonant-cascaded extended state observer structure to achieve error-free tracking of the current input to the observer during the dynamic process; removing the traditional compensation voltage PI calculation link, directly extracting the compensation voltage using the resonant-cascaded extended state observer, and combining with a resonant controller to eliminate the current harmonics with specific frequencies in the current harmonics and ensure enhanced harmonic suppression effect at steady state. This patent application requires two extended state observers to be cascaded, and still needs to consider the influence caused by parameter transformation during the actual operation of the motor. Summary of the Invention

[0004] In order to overcome the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a method, device and system for suppressing current harmonics of a permanent magnet synchronous motor, which can not only improve the dynamic performance and steady-state performance of the system, but also ensure the accuracy of the generated compensation voltage. The influence of the observer performance defect on the current harmonic suppression effect is reduced, so that the error of current harmonic tracking is reduced on the premise of ensuring rapidity.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is: In a first aspect, the present invention provides a method for suppressing current harmonics of a permanent magnet synchronous motor, comprising the following steps: According to the current harmonic model of the permanent magnet synchronous motor, in the d-q synchronous rotating coordinate system, the three-phase stator current is transformed into the d-axis current and the q-axis current; According to the current harmonic model of the permanent magnet synchronous motor, in the d-q synchronous rotating coordinate system, the d-axis voltage u d and the q-axis voltage u q are calculated; The d-axis current and the q-axis current, the d-axis voltage and the q-axis voltage are injected into the resonant-cascade extended state observer to obtain the estimated value of the input current and the compensation voltage value; The compensation voltage value generated by the resonant-cascade extended state observer is injected into the current inner loop of the vector control of the permanent magnet synchronous motor and added to the d-axis voltage and the q-axis voltage.

[0006] Optionally, the current equations of the d-axis and q-axis of the current harmonics are:

[0007] where, i 1th is the amplitude of the fundamental current; θ 1 is the initial phase angle of the fundamental current; i 1th is the amplitude of the fundamental current; i (6n-1)th and i (6n+1)th are the amplitudes of the stator current harmonics; θ 6n-1 and θ 6n+1 are the initial phase angles of the stator current harmonics; ω is the electrical angular velocity; the 6n-1th and 6n+1th harmonics of the stator current are transformed into the 6nth harmonic in the d-axis current and the q-axis current.

[0008] Optionally, the voltage equations of the d-axis voltage u d and the q-axis voltage u q are:

[0009] where, u d and u q are the d-axis and q-axis components of the stator voltage respectively; i d and i q are the d-axis and q-axis components of the stator current respectively; L d and L qare the d-axis and q-axis components of the stator inductance, respectively; R s is the stator resistance; ω is the electrical angular velocity; ѱ f is the magnetic flux linkage of the permanent magnet.

[0010] Optionally, the state equation of the resonance-cascade extended state observer is:

[0011] where, y is the input current of the resonance-cascade extended state observer, z 1 is the estimated value of the input current by the resonance-cascade extended state observer, u is the input voltage of the resonance-cascade extended state observer, z 2 is the voltage compensation value generated by the resonance-cascade extended state observer, e 1 is the error between the input current and the estimated current of the resonance-cascade extended state observer, R ( s ) is the expression of the resonance controller, β 1 and β 2 are the coefficients of the resonance-cascade extended state observer, b 0 is the stator inductance L s is the reciprocal of;

[0012] where, y is the input current of the resonance-cascade extended state observer, s 1 is the estimated value of the input current by the resonance-cascade extended state observer, u is the input voltage of the resonance-cascade extended state observer, s 2 is the voltage compensation value generated by the resonance-cascade extended state observer, z 2 is the voltage compensation value generated by the resonance-cascade extended state observer, e 2 is the error between the input current and the estimated current of the resonance-cascade extended state observer, β 21 and β 22 are the coefficients of the resonance-cascade extended state observer, b 0 is the stator inductanceL s The reciprocal of

[0013] Optionally, the transfer function of the resonance controller is:

[0014] where k a is the resonance coefficient, ω a is the resonance angular frequency, ω c is the resonance bandwidth, and s is a complex plane variable.

[0015] Optionally, the parameters of the resonance-cascade extended state observer are:

[0016] where ω 0 is the resonance-cascade extended state observer bandwidth; β 1 , β 2 , β 11 , β 12 , β 21 and β 22 are all coefficients of the resonance-cascade extended state observer.

[0017] Optionally, the harmonic tracking transfer function of the resonance-cascade extended state observer is:

[0018]

[0019] where G QR-CESO-HE (s) is the harmonic tracking transfer function of the resonance-cascade extended state observer; N0, N1, N2, N3, N4 represent the numerator coefficients; s represents a complex plane variable; D0, D1, D2, D3, D4, D5 represent the denominator coefficients; β 11 , β 12 , β 21 and β 22 are all coefficients of the resonance-cascade extended state observer; k a is the resonance coefficient; ω a is the resonance angular frequency;ω c is the resonance bandwidth.

[0020] Optionally, the harmonic error tracking transfer function of the resonance-cascade extended state observer is:

[0021]

[0022] where G QR-CESO-HEE (s) is the harmonic error tracking transfer function of the resonance-cascade extended state observer; M2, M3, M4, M5 represent the numerator coefficients; s represents the complex plane variable; D0, D1, D2, D3, D4, D5 represent the denominator coefficients; β 11 , β 12 , β 21 and β 22 are all coefficients of the resonance-cascade extended state observer; k a is the resonance coefficient; ω a is the resonance angular frequency; ω c is the resonance bandwidth.

[0023] In a second aspect, the present invention provides a permanent magnet synchronous motor current harmonic suppression device for the above-mentioned permanent magnet synchronous motor current harmonic suppression method, including: A first subtractor for calculating the difference between the feedback motor speed ω and the given motor speed ω*; A first PI controller for inputting the result of the first subtractor and outputting the q-axis current iq*; A second subtractor for calculating the difference between the q-axis current iq* and the feedback q-axis current iq; A third subtractor for calculating the difference between the given d-axis current id* and the feedback d-axis current id; A second PI controller for inputting the result of the second subtractor and outputting the actual q-axis voltage uq; A third PI controller for inputting the result of the third subtractor and outputting the actual d-axis voltage ud; The resonance-cascade extended state observer includes a resonance-extended state observer, an extended state observer, and an observer subtractor; the resonance-extended state observer is used to input the feedback d-axis current id, the feedback q-axis current iq, the feedback motor speed ω, the actual q-axis voltage uq, the actual d-axis voltage ud, and output the compensation voltage z2; the extended state observer is used to input the feedback d-axis current id, the feedback q-axis current iq, and the intermediate state variable p1, and output the compensation voltage s2; the observer adder is used to input z2 and s2 and output △uq and △ud; The fourth adder is used to calculate the sum of the actual q-axis voltage uq and the q-axis compensation voltage △uq; The fifth adder is used to calculate the sum of the actual d-axis voltage ud and the d-axis compensation voltage △ud; The Park transformation controller is used to input the results of the fourth adder and the fifth adder and output the voltages uα and uβ in the αβ axis; The space vector pulse width modulator is used to input the results of the Park transformation controller and output the inverter control signal; The inverter is used to input the results of the space vector pulse width modulator and output three-phase currents to the motor; The Clark converter is used to input the three-phase currents of the motor and output two-phase currents id and iq; The encoder is used to obtain the feedback motor speed ω.

[0024] In a third aspect, the present invention provides a permanent magnet synchronous motor current harmonic suppression system, including: The first calculation module is used to transform the three-phase stator currents into d-axis current and q-axis current in the d-q synchronous rotating coordinate system according to the permanent magnet synchronous motor current harmonic model; The second calculation module is used to calculate the d-axis voltage u d and the q-axis voltage u q ; The third calculation module is used to inject the d-axis current and q-axis current, the d-axis voltage and q-axis voltage into the resonance-cascade extended state observer to obtain the estimated value of the input current and the compensation voltage value; The fourth calculation module is used to inject the compensation voltage value generated by the resonance-cascade extended state observer into the permanent magnet synchronous motor vector control current inner loop and add it to the d-axis voltage and q-axis voltage.

[0025] Compared with the prior art, the present invention has the following beneficial effects: The present invention adopts a resonance-cascade extended state observer compensation voltage generation method, which can suppress the 6th current harmonics in the d-axis current id and the q-axis current iq, improves the structure of the traditional extended state observer, and has strong robustness without considering the influence caused by parameter transformation during the actual operation of the motor.

[0026] The resonance-cascade extended state observer compensation voltage generation method in the present invention can not only ensure the fast dynamic response of harmonic suppression, but also, compared with the current harmonic suppression of the traditional extended state observer, combine the resonance link of the resonance controller, and the resonance-cascade extended state observer can improve the suppression effect of current harmonics.

[0027] The resonance-cascade extended state observer compensation voltage generation method in the present invention has a simple and clear design idea, the method itself has a simple program and is easy to be programmed and implemented. Therefore, it can be carried on the existing mature digital signal processor to operate normally, without developing a new hardware platform, which can greatly reduce the labor and economic costs and is easy for batch production.

[0028] The resonance-cascade extended state observer compensation voltage generation method in the present invention occupies very little resources of the control system, will not cause the situation that the memory of the digital controller is not enough, nor will it cause obvious system lag.

[0029] The present invention can be applied to the current harmonic suppression of the permanent magnet synchronous motor vector control system under different torque conditions.

[0030] The generation of the compensation voltage through the resonance-cascade extended state observer in the present invention has a simple and clear design idea, the observer parameters are easy to adjust, and it has the ability of small current overshoot and fast response during the dynamic process.

[0031] Finally, the present invention superimposes the calculated compensation voltage on the reference voltage, thereby canceling the harmonic components in the reference voltage and realizing the suppression of current harmonics. Compared with the traditional extended state observer, the resonance-cascade extended state observer has a faster response speed and higher tracking accuracy during the whole dynamic process, can achieve zero-error tracking of current harmonics, and ensure the optimal suppression effect of steady-state current harmonics. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the disclosure of the present invention in any way.

[0033] In the drawings: Figure 1 is the principle block diagram of the method of the present invention; Figure 2 is the principle block diagram of generating the compensation voltage based on the resonance-cascade extended state observer; Figure 3It is the structural block diagram of the resonance-cascade extended state observer designed by the present invention; Figure 4 It is the experimental diagram of the phase-A current without current harmonic suppression in Embodiment 1; Figure 5 It is the experimental result of the Fourier analysis of the phase-A current without current harmonic suppression in Embodiment 1; Figure 6 It is the experimental diagram of the d-axis current without current harmonic suppression in Embodiment 1; Figure 7 It is the experimental diagram of the q-axis current without current harmonic suppression in Embodiment 1; Figure 8 It is the waveform of the phase-A current of the current harmonic suppression method based on the resonance-cascade extended state observer under the conditions of a load torque of 18 N·m and a motor speed of 600 r / min in Embodiment 2; Figure 9 It is the experimental result of the Fourier analysis of the phase-A current of the current harmonic suppression method based on the resonance-cascade extended state observer under the conditions of a load torque of 18 N·m and a motor speed of 600 r / min in Embodiment 2; Figure 10 It is the waveform of the d-axis current of the current harmonic suppression method based on the resonance-cascade extended state observer under the conditions of a load torque of 18 N·m and a motor speed of 600 r / min in Embodiment 2; Figure 11 It is the waveform of the q-axis current of the current harmonic suppression method based on the resonance-cascade extended state observer under the conditions of a load torque of 18 N·m and a motor speed of 600 r / min in Embodiment 2; Figure 12 It is the waveform of the d-axis compensation voltage of the current harmonic suppression method based on the resonance-cascade extended state observer under the conditions of a load torque of 18 N·m and a motor speed of 600 r / min in Embodiment 2; Figure 13 It is the experimental result of the Fourier analysis of the d-axis compensation voltage of the current harmonic suppression method based on the resonance-cascade extended state observer under the conditions of a load torque of 18 N·m and a motor speed of 600 r / min in Embodiment 2; Figure 14 It is the waveform of the q-axis compensation voltage of the current harmonic suppression method based on the resonance-cascade extended state observer under the conditions of a load torque of 18 N·m and a motor speed of 600 r / min in Embodiment 2; Figure 15 It is the experimental result of the Fourier analysis of the q-axis compensation voltage of the current harmonic suppression method based on the resonance-cascade extended state observer under the conditions of a load torque of 18 N·m and a motor speed of 600 r / min in Embodiment 2; Figure 16Open-loop and closed-loop experimental results of the current harmonic suppression method based on the resonant-cascade extended state observer under the conditions of a load torque of 18 N·m and a motor speed of 600 r / min in Example 3; Figure 17 Experimental results of the current harmonic suppression method based on the resonant-cascade extended state observer with the dead time ranging from 5 µs to 7 µs under the conditions of a load torque of 18 N·m and a motor speed of 600 r / min in Example 3; Figure 18 d-axis current waveform of the current harmonic suppression method based on the resonant-cascade extended state observer under the condition of the load torque increasing from 18 N·m to 26 N·m in Example 3; Figure 19 q-axis current waveform of the current harmonic suppression method based on the resonant-cascade extended state observer under the condition of the load torque increasing from 18 N·m to 26 N·m in Example 3; Figure 20 A-phase current waveform of the current harmonic suppression method based on the resonant-cascade extended state observer under the conditions of a load torque of 18 N·m and a motor speed of 1800 r / min in Example 4; Figure 21 Experimental results of the Fourier analysis of the A-phase current of the current harmonic suppression method based on the resonant-cascade extended state observer under the conditions of a load torque of 18 N·m and a motor speed of 1800 r / min in Example 4; Figure 22 d-axis compensation voltage waveform of the current harmonic suppression method based on the resonant-cascade extended state observer under the conditions of a load torque of 18 N·m and a motor speed of 1800 r / min in Example 4; Figure 23 Experimental results of the Fourier analysis of the d-axis compensation voltage of the current harmonic suppression method based on the resonant-cascade extended state observer under the conditions of a load torque of 18 N·m and a motor speed of 1800 r / min in Example 4; Figure 24 q-axis compensation voltage waveform of the current harmonic suppression method based on the resonant-cascade extended state observer under the conditions of a load torque of 18 N·m and a motor speed of 1800 r / min in Example 4; Figure 25 Experimental results of the Fourier analysis of the q-axis compensation voltage of the current harmonic suppression method based on the resonant-cascade extended state observer under the conditions of a load torque of 18 N·m and a motor speed of 1800 r / min in Example 4. Detailed implementation manners

[0034] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0035] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0036] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper", "lower", "horizontal", "inner", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use. It is 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, and thus cannot be construed as a limitation on the present invention.

[0037] When an element is referred to as being "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be intermediate elements at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments. If the term "horizontal" appears, it does not mean that the component is required to be absolutely horizontal, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0038] It should be noted that: similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In the description of the present invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their combinations.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. The terms used in the description of the present invention herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. As used in the description of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0040] The present invention will be described in detail below with reference to the accompanying drawings.

[0041] As Figure 1 shown, a method for suppressing current harmonics of a permanent magnet synchronous motor according to the present invention includes the following steps: S1: According to the current harmonic model of the permanent magnet synchronous motor, the three-phase stator current has 6n±1 order (n = 1, 2, 3...) current harmonics. In the d-q synchronous rotating coordinate system, ignoring the flux linkage harmonics, the three-phase stator current is transformed into the d-axis current and the q-axis current. The d-axis and q-axis current equations including the current harmonics are as follows:

[0042] where, i 1th is the amplitude of the fundamental current; θ 1 is the initial phase angle of the fundamental current; i 1th is the amplitude of the fundamental current; i (6n-1)th and i (6n+1)th are the amplitudes of the stator current harmonics; θ 6n-1 and θ 6n+1 are the initial phase angles of the stator current harmonics; ω is the electrical angular velocity; the 6n-1th and 6n+1th harmonics of the stator current are transformed into the 6nth harmonic in the d-axis current and the q-axis current.

[0043] S2: According to the current harmonic model of the permanent magnet synchronous motor, in the d-q synchronous rotating coordinate system, the d-axis voltage u d and the q-axis voltage u q have the following voltage equations:

[0044] where, u d and u q are the d-axis and q-axis components of the stator voltage respectively; i d and i q are the d-axis and q-axis components of the stator current respectively; L d andL q are the d-axis and q-axis components of the stator inductance respectively; R s is the stator resistance; ω is the electrical angular velocity; ѱ f is the magnetic flux linkage of the permanent magnet.

[0045] S3: Inject the d-axis current and q-axis current, and the d-axis voltage and q-axis voltage into the resonance-cascade extended state observer. The observer can obtain the estimated value of the input current and the compensation voltage value. Combining with the resonance controller, the ability to suppress current harmonics is enhanced.

[0046] S4: Inject the compensation voltage value generated by the resonance-cascade extended state observer into the current inner loop of the permanent magnet synchronous motor vector control, and add it to the d-axis voltage and q-axis voltage.

[0047] Specifically, since the amplitude of the stator current harmonics decreases with the increase of the stator current harmonic order, and the amplitude of the low-order stator current harmonics is relatively large, the stator current harmonics are the 5th, 7th, 11th, and 13th order stator current harmonics. When considering the 5th, 7th, 11th, and 13th order stator current harmonics, the 5th and 7th order harmonics of the stator current are transformed into the 6th harmonic in the d-axis current and q-axis current, and the 11th and 13th order harmonics of the stator current are transformed into the 12th harmonic in the d-axis current and q-axis current. Inject the d-axis current and q-axis current, and the d-axis voltage and q-axis voltage into the resonance-cascade extended state observer, obtain the compensation voltage value through the observer, and then add the compensation voltage value to the d-axis voltage and q-axis voltage in the current inner loop.

[0048] A current harmonic suppression system for a permanent magnet synchronous motor of the present invention includes: A first calculation module, configured to transform the three-phase stator current into the d-axis current and q-axis current in the d-q synchronous rotating coordinate system according to the permanent magnet synchronous motor current harmonic model. The current equations including the current harmonics of the d-axis and q-axis are:

[0049] where, i 1th is the amplitude of the fundamental current; θ 1 is the initial phase angle of the fundamental current; i 1th is the amplitude of the fundamental current; i (6n-1)th and i (6n+1)th are the amplitudes of the stator current harmonics; θ 6n-1 and θ 6n+1 are the initial phase angles of the stator current harmonics; ω is the electrical angular velocity; The (6n - 1)th and (6n + 1)th order harmonics of the stator current are transformed into the 6nth harmonic in the d-axis current and q-axis current.

[0050] The second calculation module calculates the d-axis voltage in the d-q synchronous rotating coordinate system according to the permanent magnet synchronous motor current harmonic model. u d and the q-axis voltage u q , and the voltage equation is:

[0051] where u d and u q are the d-axis and q-axis components of the stator voltage respectively; i d and i q are the d-axis and q-axis components of the stator current respectively; L d and L q are the d-axis and q-axis components of the stator inductance respectively; R s is the stator resistance; ω is the electrical angular velocity; ѱ f is the magnetic flux linkage of the permanent magnet.

[0052] The third calculation module injects the obtained d-axis current, q-axis current, d-axis voltage and q-axis voltage into a Quasi-Resonant Control Extended State Observer (QR-CESO), and generates the compensation voltage value to be injected through the QR-CESO. The fourth calculation module is used to inject the compensation voltage value generated by the QR-CESO into the inner current loop of the permanent magnet synchronous motor vector control and add it to the d-axis voltage and q-axis voltage.

[0053] Since the QR-CESO has the advantages of good dynamic performance and steady-state performance, does not depend on motor parameters, has strong system stability and high tracking accuracy, the specific process of generating the compensation voltage by the current harmonic suppression method based on the QR-CESO is as follows: First, convert the three-phase mathematical model of the permanent magnet synchronous motor into the d-axis voltage ud and q-axis voltage uq in the d-q synchronous rotating coordinate system, and regard the motor as an ideal structure, ignoring the magnetic flux harmonic, and establish the voltage equation of the permanent magnet synchronous motor.

[0054] where, the d-axis voltage ud and q-axis voltage uq are the d-axis and q-axis components of the stator voltage respectively; the d-axis current id and q-axis current iq are the d-axis and q-axis components of the stator current respectively; Ld and L q are the d-axis and q-axis components of the stator inductance respectively; R s is the stator resistance; ω is the electrical angular velocity; ѱ f is the magnetic flux linkage of the permanent magnet.

[0055] Then, in an actual motor control system, the stator windings of a permanent magnet synchronous motor are star-connected. Under ideal conditions, the stator windings are symmetrically distributed. Therefore, there are no 3n-order (n = 1, 3, 5, …) and even-order stator current harmonics, and the phase difference of the stator current harmonics is 2nπ / 3. So the stator current harmonics can be expressed as:

[0056] where, i an , i bn , i cn are the n-order stator current harmonics of phase a, phase b, and phase c respectively; i nth is the amplitude of the n-order stator current harmonic; θ n is the initial phase of the n-order stator current harmonic.

[0057] Substitute the current equation of the permanent magnet synchronous motor containing the 6nth current harmonic in the d-q synchronous rotating coordinate system into the voltage equation of the permanent magnet synchronous motor in the d-q synchronous rotating coordinate system, and the voltage equation of the permanent magnet synchronous motor containing the 6nth current harmonic is obtained.

[0058] Furthermore, the three-phase stator current has 6n±1-order (n = 1, 2, 3, …) current harmonics, and the amplitude of the stator current harmonic decreases with the increase of the stator current harmonic order. The amplitude of the low-order stator current harmonic is larger. Therefore, the stator current harmonics are the 5th, 7th, 11th, and 13th order stator current harmonics. When considering the 5th, 7th, 11th, and 13th order stator current harmonics, the three-phase stator current of the permanent magnet synchronous motor can be expressed as:

[0059] where, i 1th , i 5th , i 7th , i 11th and i 13th are the amplitudes of the fundamental current, the 5th, 7th, 11th, and 13th order stator current harmonics respectively; θ 1 , θ 5 , θ 7 , θ 11 and θ 13 are the initial phase angles of the fundamental current, the 5th, 7th, 11th, and 13th order stator current harmonics respectively.

[0060] Under the constraint of constant amplitude transformation, the three-phase stator currents are transformed into the d-axis current \(i_d\) and the q-axis current \(i_q\) in the d-q synchronous rotating coordinate system. The 5th and 7th current harmonics in the three-phase stator currents are transformed into the 6th current harmonic in the d-axis current \(i_d\) and the q-axis current \(i_q\), and the 11th and 13th current harmonics in the three-phase stator currents are transformed into the 12th harmonic in the d-axis current \(i_d\) and the q-axis current \(i_q\). Therefore, the current equation of the permanent magnet synchronous motor containing the 6th and 12th current harmonics in the d-q synchronous rotating coordinate system is as follows:

[0061] where \(i\) 1th , \(i\) 5th , \(i\) 7th , \(i\) 11th and \(i\) 13th are the amplitudes of the fundamental current, the 5th, 7th, 11th, and 13th stator current harmonics respectively; \(\theta\) 1 , \(\theta\) 5 , \(\theta\) 7 , \(\theta\) 11 and \(\theta\) 13 are the initial phase angles of the fundamental current, the 5th, 7th, 11th, and 13th stator current harmonics respectively.

[0062] Finally, substituting the current equation of the permanent magnet synchronous motor containing the 6th and 12th current harmonics in the d-q synchronous rotating coordinate system into the voltage equation of the permanent magnet synchronous motor in the d-q synchronous rotating coordinate system, the voltage equation of the permanent magnet synchronous motor containing the 6th and 12th current harmonics can be obtained as:

[0063] where \(i\) 1th , \(i\) 5th , \(i\) 7th , \(i\) 11th and \(i\) 13th are the amplitudes of the fundamental current, the 5th, 7th, 11th, and 13th stator current harmonics respectively; \(\theta\) 1 , \(\theta\) 5 , \(\theta\) 7 , \(\theta\) 11 and \(\theta\) 13 are the initial phase angles of the fundamental current, the 5th, 7th, 11th, and 13th stator current harmonics respectively; \(L\) d and \(L\) q are the d-axis and q-axis components of the stator inductance respectively; \(R\) s is the stator resistance; \(\omega\) is the electrical angular velocity; \(\varPsi\) f is the magnetic flux of the permanent magnet.

[0064] The state equation of the traditional Extended State Observer (ESO) is as follows:

[0065] Among them, y is the input current of the Extended State Observer, z 1 is the estimated value of the input current by the Extended State Observer, u is the input voltage of the Extended State Observer, z 2 is the voltage compensation value generated by the Extended State Observer, e 1 is the error between the input current and the current estimated value of the Extended State Observer, β 1 and β 2 are the coefficients of the Extended State Observer, b 0 is the stator inductance L s is the reciprocal of

[0066] Precise and fast tracking of current harmonics is the key to measuring the performance of the observer. Therefore, the harmonic tracking transfer function between the current harmonic estimated value z 2 and the true value x 2 is as follows:

[0067] Among them, β 1 and β 2 are the coefficients of the Extended State Observer, and s is a complex plane variable The harmonic zero-error tracking transfer function between the current harmonic estimated value z 2 and the true value x 2 is

[0068] Among them, β 1 and β 2 are the coefficients of the Extended State Observer, and s is a complex plane variable The state equation of the Resonant-Cascade Extended State Observer is as follows:

[0069] Among them, y is the input current of the Resonant-Cascade Extended State Observer, z 1is the estimated value of the input current by the resonant-cascade extended state observer, u is the input voltage of the resonant-cascade extended state observer, z 2 is the voltage compensation value generated by the resonant-cascade extended state observer, e 1 is the error between the input current and the estimated current of the resonant-cascade extended state observer, R ( s ) is the expression of the resonant controller, β 1 and β 2 are the coefficients of the resonant-cascade extended state observer, b 0 is the stator inductance L s the reciprocal of.

[0070]

[0071] Wherein, y is the input current of the resonant-cascade extended state observer, s 1 is the estimated value of the input current by the resonant-cascade extended state observer, u is the input voltage of the resonant-cascade extended state observer, s 2 is the voltage compensation value generated by the resonant-cascade extended state observer, z 2 is the voltage compensation value generated by the resonant-cascade extended state observer, e 2 is the error between the input current and the estimated current of the resonant-cascade extended state observer, β 21 and β 22 are the coefficients of the resonant-cascade extended state observer, b 0 is the stator inductance L s the reciprocal of.

[0072] The transfer function of the resonant controller is:

[0073] Wherein, k a is the resonant coefficient, ω a is the resonant angular frequency, ω c is the resonant bandwidth, s is the complex plane variable.

[0074] To ensure the steady-state and dynamic performance of the observer, the parameters of the observer are designed strictly according to the bandwidth method, and the parameters of the resonance-cascade extended state observer are designed as follows:

[0075] where ω 0 is the observer bandwidth.

[0076] The harmonic tracking transfer function of the resonance-cascade extended state observer is:

[0077]

[0078] where G QR-CESO-HE (s) is the harmonic tracking transfer function of the resonance-cascade extended state observer; N0, N1, N2, N3, N4 represent the numerator coefficients; s represents the complex plane variable; D0, D1, D2, D3, D4, D5 represent the denominator coefficients; β 11 , β 12 , β 21 and β 22 are all coefficients of the resonance-cascade extended state observer; k a is the resonance coefficient; ω a is the resonance angular frequency; ω c is the resonance bandwidth.

[0079] The harmonic error tracking transfer function of the resonance-cascade extended state observer is:

[0080]

[0081] where G QR-CESO-HEE (s) is the harmonic error tracking transfer function of the resonance-cascade extended state observer; M2, M3, M4, M5 represent the numerator coefficients; s represents the complex plane variable; D0, D1, D2, D3, D4, D5 represent the denominator coefficients; β 11 , β 12 , β 21 and β 22 are all coefficients of the resonance-cascade extended state observer; ka is the resonance coefficient; ω a is the resonance angular frequency; ω c is the resonance bandwidth.

[0082] As Figure 1 shown, the present invention proposes a method for suppressing current harmonics of a permanent magnet synchronous motor based on a resonance-cascade extended state observer, including current harmonic tracking, generation of compensation voltage, and injection of compensation voltage. The resonance-cascade extended state observer current harmonic suppression method of the present invention can be applied to the vector control system of a permanent magnet synchronous motor. In principle, it uses the compensation voltage generation method of the resonance-cascade extended state observer to inject the d-axis current id and q-axis current iq, d-axis voltage ud and q-axis voltage uq into the resonance-cascade extended state observer, and generates a compensation voltage through the resonance-cascade extended state observer with small current overshoot and fast response during the dynamic process. Then, the generated compensation voltage value is injected into the current inner loop of the vector control of the permanent magnet synchronous motor and added to the d-axis voltage ud and q-axis voltage uq. The voltage compensation signal is superimposed on the voltage command output by the current inner loop controller and used as the input of the subsequent PWM modulation module. After PWM modulation, it acts on the controlled object (motor) and produces the desired control effect to achieve the suppression of current harmonics caused by the dead-time effect of the inverter.

[0083] Next, a method for suppressing current harmonics of a permanent magnet synchronous motor based on a resonance-cascade extended state observer will be specifically described by taking the vector control system of a permanent magnet synchronous motor as an example. The structure of the compensation voltage extraction method of the resonance-cascade extended state observer used in this embodiment is as Figure 2 shown.

[0084] As Figure 2, the d-axis current \(i_d\) and q-axis current \(i_q\), as well as the d-axis voltage \(u_d\) and q-axis voltage \(u_q\) are injected into the resonant-cascade extended state observer. The resonant-cascade extended state observer can achieve the non-error tracking of the input currents \(i_d\) and \(i_q\). Combining with the suppression effect of the resonant controller on the current harmonics at specific frequencies, the harmonic content of the estimated current obtained by the resonant-cascade extended state observer is less. In addition, the resonant-cascade extended state observer can directly obtain the compensation voltage without the need to calculate the compensation voltage through the PI link, improving the overall dynamic response speed of the system and also solving the problem of the influence of motor parameter changes on the compensation voltage during the actual operation of the motor. In the resonant-cascade extended state observer proposed in the present invention, according to the double ESO cascade structure, the resonant-cascade extended state observer can obtain better steady-state performance and, combined with the QR controller, improves the ability to suppress current harmonics. In addition, the newly introduced ESO can effectively estimate some of the harmonics provided by the QR-ESO. Therefore, the resonant-cascade extended state observer improves the dynamic performance. When the harmonic content changes, the resonant-cascade extended state observer can suppress the current harmonics and enable the system to reach the steady state faster.

[0085] Such as Figure 3 , the three-phase currents of the motor are transformed to the fundamental d-q axis coordinate system through Clarke and Park transformations. The positive-sequence components of the fundamental wave of the phase currents are transformed into direct currents, and the other components are transformed into AC components of each frequency. Taking the q-axis as an example, first, the q-axis current is respectively input into the two extended state observers of the resonant-cascade extended state observer, and the q-axis current is tracked simultaneously. Among them, the resonant-extended state observer (QR-ESO) combines the resonant controller for suppressing current harmonics and the extended state observer for improving the dynamic response speed to current harmonics, thus improving the dynamic performance of the resonant-cascade extended state observer. The variable p 1 makes s 2 estimate the remaining harmonics except z 2 , compensate the initial estimate of the QR-ESO, and improve the dynamic tracking speed of the harmonics and the stability of the system. At the same time, a resonant link is introduced into the system to enhance the ability of the system to suppress current harmonics. The obtained z 2 and s 2 are added together to obtain the compensation voltage output by the resonant-cascade extended state observer, which is injected into the d-axis voltage \(u_d\) and q-axis voltage \(u_q\) of the current inner loop to suppress the current harmonics.

[0086] Embodiment 1 The comparison diagram of the experimental results without current harmonic suppression of a certain interior permanent magnet synchronous motor vector control system in this embodiment under the conditions of a motor speed of 600 r / min and a load torque of 18 N·m is as Figures 4 to 7 shown. Figure 4 and Figure 5The experimental results of the A-phase current without current harmonic suppression and its Fourier analysis, respectively. Figure 6 and Figure 7 The experimental results of the d-axis current and q-axis current without current harmonic suppression, respectively. Figure 4 and Figure 5 Show the A-phase current waveform without current harmonic suppression and its fast Fourier transform (FFT) analysis at a motor speed of 600 r / min and a load torque of 18 N·m. From Figure 4 It can be seen that due to the influence of the dead time, the sine waveform of the A-phase current without current harmonic suppression is affected, and the current harmonic contents of the 5th and 7th, 11th and 13th are too high, affecting its sine waveform, which is not conducive to the normal operation of the motor. In Figure 5 , through FFT analysis, in the A-phase current without current harmonic suppression, the fundamental wave content amplitude is 28.57 dB, the 5th current harmonic amplitude is 2.92 dB, the 7th current harmonic amplitude is -0.66 dB, the 11th current harmonic amplitude is -5.73 dB, and the 13th current harmonic amplitude is -9.21 dB. Figure 6 and Figure 7 Waveform diagrams of the d-axis current and q-axis current without current harmonic suppression. From Figure 6 It can be seen that without current harmonic suppression, the waveform of the d-axis current is similar to a triangular wave, and the fluctuation range is within -5A to 5A. In Figure 7 , without current harmonic suppression, the waveform of the q-axis current is similar to a triangular wave, and the fluctuation range is within 26 A to 28A.

[0087] Embodiment 2 The experimental result diagram of a certain interior permanent magnet synchronous motor vector control system using the resonant-cascade extended state observer current harmonic suppression method at a motor speed of 600 r / min and a load torque of 18 N·m is as shown in Figures 8 to 15 shown. Figure 8 Is the A-phase current waveform based on the resonant-cascade extended state observer current harmonic suppression method, and its sine signal waveform is improved, indicating that the harmonic content contained in the A-phase current is reduced. Figure 9 Are the experimental results of the Fourier analysis of the A-phase current based on the resonant-cascade extended state observer current harmonic suppression method. The fundamental wave content amplitude is 28.57 dB, the 5th current harmonic amplitude is -22.56 dB, the 7th current harmonic amplitude is -26.17 dB, the 11th current harmonic amplitude is -9.53 dB, and the 13th current harmonic amplitude is -11.54 dB. Figure 10 Is the experimental result of the d-axis current waveform based on the resonant-cascade extended state observer current harmonic suppression method. Figure 11It is the experimental result of the q-axis current waveform based on the current harmonic suppression method of the resonance-cascade extended state observer. Figure 12 It is the experimental result of the d-axis compensation voltage waveform based on the current harmonic suppression method of the resonance-cascade extended state observer, and its fluctuation range is from -20 V to 0 V. Figure 13 It is the experimental result of the Fourier analysis of the d-axis compensation voltage based on the current harmonic suppression method of the resonance-cascade extended state observer. The amplitude of the 6th current harmonic is 19.55 dB, and the amplitude of the 12th current harmonic is 9.05 dB. Figure 14 It is the experimental result of the q-axis compensation voltage waveform based on the current harmonic suppression method of the resonance-cascade extended state observer, and its fluctuation range is from 55 A to 60 A. Figure 15 It is the experimental result of the Fourier analysis of the q-axis compensation voltage based on the current harmonic suppression method of the resonance-cascade extended state observer. The amplitude of the 6th current harmonic is 6.10 dB, and the amplitude of the 12th current harmonic is -13.17 dB.

[0088] Example 3 The experimental result diagrams of the current harmonic suppression method based on the resonance-cascade extended state observer of a certain interior permanent magnet synchronous motor vector control system at a speed of 600 r / min are respectively as Figures 16 to 19 shown. Figure 16 It is the system open-loop and closed-loop experimental result based on the current harmonic suppression method of the resonance-cascade extended state observer. Under the compensation voltage generated by the resonance-cascade extended state observer, the dynamic process of the stable a-phase current requires about 20 ms. The d-axis and q-axis compensation voltage waveforms remain unchanged and are not affected. Figure 17 The experimental result based on the current harmonic suppression method of the resonance-cascade extended state observer under the condition that the dead time ranges from 5 µs to 7 µs. When the dead time suddenly changes, the d-axis compensation voltage generated by QR-CESO increases, and its dynamic process takes about 5 ms; when the q-axis compensation voltage increases, its dynamic process takes about 10 ms; the q-axis current result remains unchanged, and its dynamic process takes about 5 ms. Figure 18 The d-axis current waveform based on the current harmonic suppression method of the resonance-cascade extended state observer under the condition that the load torque increases from 18 N·m to 26 N·m. Before the load increases, id fluctuates between -1.5 A and 2 A, and after the load increases, id fluctuates between -1.5 A and 2.5 A. Figure 19 The q-axis current waveform based on the current harmonic suppression method of the resonance-cascade extended state observer under the condition that the load torque increases from 18 N·m to 26 N·m. Before the load increases, iq fluctuates between 26.5 A and 27.5 A, and after the load increases, iq fluctuates between 38.5 A and 39.5 A.

[0089] Example 4 The experimental results of the current harmonic suppression method based on the resonance-cascade extended state observer for a certain built-in permanent magnet synchronous motor vector control system in this embodiment are as follows under the conditions of a rotational speed of 1800 r / min and 18 N·m Figures 20 to 25 as shown. Figure 20 It is the A-phase current waveform of the current harmonic suppression method based on the resonance-cascade extended state observer. Figure 21 It is the experimental result of the Fourier analysis of the A-phase current of the current harmonic suppression method based on the resonance-cascade extended state observer. Figure 22 It is the d-axis compensation voltage waveform of the current harmonic suppression method based on the resonance-cascade extended state observer. Figure 23 It is the experimental result of the Fourier analysis of the d-axis compensation voltage of the current harmonic suppression method based on the resonance-cascade extended state observer, where the amplitude of the 6th current harmonic is 16.42 dB and the amplitude of the 12th current harmonic is 6.91 dB. Figure 24 It is the q-axis compensation voltage waveform of the current harmonic suppression method based on the resonance-cascade extended state observer. Figure 25 It is the experimental result of the Fourier analysis of the q-axis compensation voltage of the current harmonic suppression method based on the resonance-cascade extended state observer, where the amplitude of the 6th current harmonic is 3.08 dB and the amplitude of the 12th current harmonic is -16.12 dB.

[0090] In the above embodiments, the equipment components involved are all conventional equipment components without special instructions. The structural setting methods, working methods, or control methods involved are all conventional setting methods, working methods, or control methods in the art without special instructions.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not restrictive. Other modifications or equivalent replacements made by those of ordinary skill in the art to the technical solutions of the present invention should be covered within the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for suppressing current harmonics of a permanent magnet synchronous motor, characterized in that: The following steps are involved: According to the permanent magnet synchronous motor current harmonic model, the three-phase stator current is transformed into d-axis current and q-axis current in the dq synchronous rotating coordinate system; According to the permanent magnet synchronous motor current harmonic model, the d-axis voltage is calculated in the dq synchronous rotating coordinate system. u d and q-axis voltage u q ; The d-axis current and q-axis current, d-axis voltage and q-axis voltage are injected into the resonant-cascade extended state observer to obtain the estimated value of the input current and the compensation voltage value; The compensation voltage value generated by the resonant-cascade extended state observer is injected into the permanent magnet synchronous motor vector control current inner loop and added to the d-axis voltage and q-axis voltage.

2. A method for suppressing current harmonics of a permanent magnet synchronous motor according to claim 1, characterized in that: The current equations for the d-axis and q-axis of the current harmonics are: Among them, i 1th is the amplitude of the fundamental current; θ1 is the initial phase angle of the fundamental current; i 1th is the amplitude of the fundamental current; i (6n-1)th and i (6n+1)th is the amplitude of the stator current harmonics; θ 6n-1 and θ 6n+1 is the initial phase angle of the stator current harmonic; ω is the electrical angular velocity; the 6n-1th and 6n+1th harmonics of the stator current are transformed into the 6nth harmonic in the d-axis current and the q-axis current.

3. A method for suppressing current harmonics of a permanent magnet synchronous motor according to claim 1, characterized in that: d-axis voltage u d and q-axis voltage u q The voltage equation is: in, u d and u q are the d-axis and q-axis components of the stator voltage respectively; i d and i q are the d-axis and q-axis components of the stator current respectively; L d and L q are the d-axis and q-axis components of the stator inductance respectively; R s is the stator resistance; ω is the electrical angular velocity; ѱ f is the flux linkage of the permanent magnet.

4. A method for suppressing current harmonics of a permanent magnet synchronous motor according to claim 1, characterized in that: The state equation of the resonant-cascade extended state observer is: in, y is the input current of the resonant-cascade extended state observer, z 1 is the estimated value of the input current by the resonant-cascade extended state observer, u is the input voltage of the resonant-cascade extended state observer, z 2 is the voltage compensation value generated by the resonant-cascade extended state observer, e 1 is the error between the input current and the current estimate of the resonant-cascade extended state observer, R ( s ) is the expression of the resonant controller, β 1 and β 2 is the coefficient of the resonant-cascade extended state observer, b 0 is the stator inductance L s The reciprocal of in, y is the input current of the resonant-cascade extended state observer, s 1 is the estimated value of the input current by the resonant-cascade extended state observer, u is the input voltage of the resonant-cascade extended state observer, s 2 is the voltage compensation value generated by the resonant-cascade extended state observer, z 2 is the voltage compensation value generated by the resonant-cascade extended state observer, e 2 is the error between the input current and the current estimate of the resonant-cascade extended state observer, β 21 and β 22 are the coefficients of the resonant-cascade extended state observer, b 0 is the stator inductance L s The reciprocal of .

5. A method for suppressing current harmonics of a permanent magnet synchronous motor according to claim 1, characterized in that: The transfer function of the resonant controller is: in, k a is the resonance coefficient, ω a is the resonant angular frequency, ω c is the resonant bandwidth and s is a complex plane variable.

6. A method for suppressing current harmonics of a permanent magnet synchronous motor according to claim 1, characterized in that: The parameters of the resonant-cascade extended state observer are: in, ω 0 is the bandwidth of the resonant-cascade extended state observer; β 1. β 2. β 11 , β 12 , β 21 and β 22 are the coefficients of the resonant-cascade extended state observer.

7. A method for suppressing current harmonics of a permanent magnet synchronous motor according to claim 1, characterized in that: The harmonic tracking transfer function of the resonant-cascade extended state observer is: Among them, G QR-CESO-HE (s) is the harmonic tracking transfer function of the resonant-cascade extended state observer; N0, N1, N2, N3, N4 represent numerator coefficients; s represents a complex plane variable; D0, D1, D2, D3, D4, D5 represent denominator coefficients; β 11 , β 12 , β 21 and β 22 They are the coefficients of the resonant-cascade extended state observer; k a is the resonance coefficient; ω a is the resonant angular frequency; ω c is the resonant bandwidth.

8. A method for suppressing current harmonics of a permanent magnet synchronous motor according to claim 1, characterized in that: The harmonic error tracking transfer function of the resonant-cascade extended state observer is: Among them, G QR-CESO-HEE (s) is the harmonic error tracking transfer function of the resonant-cascade extended state observer; M2, M3, M4, M5 represent numerator coefficients; s represents a complex plane variable; D0, D1, D2, D3, D4, D5 represent denominator coefficients; β 11 , β 12 , β 21 and β 22 They are the coefficients of the resonant-cascade extended state observer; k a is the resonance coefficient; ω a is the resonant angular frequency; ω c is the resonant bandwidth.

9. A permanent magnet synchronous motor current harmonic suppression device, used in a permanent magnet synchronous motor current harmonic suppression method according to any one of claims 1 to 9, characterized in that: include: A first subtractor is used to calculate the difference between the feedback motor speed ω and the given motor speed ω*; A first PI controller, used for inputting the result of the first subtractor and outputting a q-axis current iq*; A second subtractor is used to calculate the difference between the q-axis current iq* and the feedback q-axis current iq; A third subtractor is used to calculate the difference between the given d-axis current id* and the d-axis current fed back by id; A second PI controller is used for inputting the result of the second subtractor and outputting an actual q-axis voltage uq; A third PI controller is used for inputting the result of the third subtractor and outputting an actual d-axis voltage ud; A resonance-cascade extended state observer, comprising a resonance-extended state observer, an extended state observer and an observer subtractor; the resonance-extended state observer is used to input feedback d-axis current id, feedback q-axis current iq, feedback motor speed ω, actual q-axis voltage uq, actual d-axis voltage ud, and output compensation voltage z2; the extended state observer is used to input feedback d-axis current id, feedback q-axis current iq, and intermediate state variable p1; output compensation voltage s2; the observer adder is used to input z2 and s2, and output △uq and △ud; a fourth adder, used for calculating the sum of the actual q-axis voltage uq and the q-axis compensation voltage △uq; a fifth adder, used for calculating the sum of the actual d-axis voltage ud and the d-axis compensation voltage △ud; A Park transformation controller, used for inputting the result of the fourth adder and the result of the fifth adder, and outputting a voltage uα under the αβ axis and a voltage uβ under the αβ axis; A space vector pulse width modulator is used to input the result of the Park transformation controller and output the inverter control signal; An inverter is used to input the result of the space vector pulse width modulator and output three-phase current to the motor; Clark converter, used to input the three-phase current of the motor and output the two-phase current id and iq; Encoder, used to get feedback motor speed ω.

10. A permanent magnet synchronous motor current harmonic suppression system, characterized in that: include: The first calculation module is used to transform the three-phase stator current into a d-axis current and a q-axis current in a dq synchronous rotating coordinate system according to a permanent magnet synchronous motor current harmonic model; The second calculation module is used to calculate the d-axis voltage in the dq synchronous rotating coordinate system according to the permanent magnet synchronous motor current harmonic model u d and q-axis voltage u q ; A third calculation module is used to inject the d-axis current and the q-axis current, the d-axis voltage and the q-axis voltage into the resonant-cascade extended state observer to obtain an estimated value of the input current and a compensation voltage value; The fourth calculation module is used to inject the compensation voltage value generated by the resonant-cascade extended state observer into the permanent magnet synchronous motor vector control current inner loop and add it to the d-axis voltage and the q-axis voltage.

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