PMSM harmonic suppression method and system based on union vector projection reconstruction

Abstract

This application discloses a PMSM harmonic suppression method and system based on union vector projection reconstruction, relating to the field of harmonic current suppression technology. The method includes: acquiring the multi-phase stator current of the target motor and performing harmonic separation based on coordinate transformation to obtain the harmonic current vector corresponding to each target subharmonic; constructing a union reference axis and projecting the harmonic current vector onto the union reference axis to obtain the active current component and reactive current component, which are then input into the corresponding proportional resonant controller to obtain the active compensation voltage component and reactive compensation voltage component; generating a harmonic compensation voltage vector and superimposing it with the fundamental control voltage vector to obtain a synthetic voltage reference vector; and performing harmonic suppression of the target motor based on the synthetic voltage reference vector. This method solves the technical problems of high computational resource consumption and coupling interference between harmonic components in existing multi-target subharmonic independent control, leading to a decrease in suppression accuracy.

Description

Technical Field

[0001] This application relates to the field of harmonic current suppression technology, specifically to a PMSM harmonic suppression method and system based on union vector projection reconstruction. Background Technology

[0002] With the widespread application of permanent magnet synchronous motors (PMSMs) in electric vehicles, industrial servo systems, and aerospace, the optimization of their electromagnetic performance has become a research direction in motor control technology. Due to the influence of factors such as the non-sinusoidal distribution of the magnetic field of permanent magnets, stator cogging effect, and inverter nonlinear characteristics, harmonic currents are inevitably generated during the operation of permanent magnet synchronous motors, which leads to increased motor torque pulsation, increased losses, and deteriorated noise, severely restricting their performance in high-precision applications.

[0003] Existing harmonic suppression technologies can be divided into two main categories: passive filtering and active control. Passive filtering methods use external inductors, capacitors, and other passive components to form a filter network. Although the structure is simple, it has inherent defects such as large size and weight, fixed parameters that are difficult to adapt to wide speed range operation, and easy resonance with system impedance. Active control methods rely on the controllability of power electronic converters and achieve harmonic mitigation through algorithm-level optimization, and are gradually becoming the mainstream technical route. Summary of the Invention

[0004] This application provides a PMSM harmonic suppression method and system based on union vector projection reconstruction, which solves the technical problems of high computational resource consumption and coupling interference between harmonic components in the existing multi-target independent control of subharmonics, resulting in a decrease in suppression accuracy.

[0005] The technical solution to the above-mentioned technical problems in this application is as follows: In a first aspect, this application provides a PMSM harmonic suppression method based on union vector projection reconstruction, the method comprising: The multiphase stator current of the target motor is collected, and harmonic separation based on coordinate transformation is performed on the multiphase stator current to obtain the harmonic current vector corresponding to each target subharmonic. Construct a union reference axis and project the harmonic current vector onto the union reference axis to obtain the corresponding active current component and reactive current component; The active current component and the reactive current component are respectively input into the corresponding proportional resonant controller, and the active compensation voltage component and reactive compensation voltage component in the union reference axis coordinate system. Based on the active power compensation voltage component and the reactive power compensation voltage component, a harmonic compensation voltage vector is generated, and superimposed with the fundamental control voltage vector to obtain a composite voltage reference vector. Harmonic suppression of the target motor is performed based on the synthesized voltage reference vector.

[0006] Secondly, this application provides a PMSM harmonic suppression system based on union vector projection reconstruction, including: The current information acquisition module is used to acquire the multiphase stator current of the target motor and perform harmonic separation based on coordinate transformation on the multiphase stator current to obtain the harmonic current vector corresponding to each target subharmonic. The current vector projection module is used to construct a union reference axis and project the harmonic current vector onto the union reference axis to obtain the corresponding active current component and reactive current component. The compensation voltage acquisition module is used to input the active current component and the reactive current component into the corresponding proportional resonant controller respectively, and acquire the active compensation voltage component and the reactive compensation voltage component in the union reference axis coordinate system. The voltage vector generation module is used to generate a harmonic compensation voltage vector based on the active power compensation voltage component and the reactive power compensation voltage component, and to superimpose it with the fundamental control voltage vector to obtain a composite voltage reference vector. The harmonic suppression module is used to suppress harmonics in the target motor based on the synthesized voltage reference vector.

[0007] This application provides one or more technical solutions, which have at least the following technical effects or advantages: This application provides a PMSM harmonic suppression method and system based on union vector projection reconstruction. First, it acquires the multiphase stator current of the target motor and performs harmonic separation based on coordinate transformation to obtain the harmonic current vector corresponding to each target subharmonic, achieving accurate extraction and independent characterization of each harmonic component in the multiphase current signal. Second, it constructs a union reference axis and projects the harmonic current vector onto this axis to obtain the corresponding active and reactive current components. A weighted vector synthesis strategy is used to fuse the direction information of multiple target subharmonics into a unified reference coordinate frame, reducing cross-coupling interference between harmonic components of different frequencies. Third, the active and reactive current components are input into the corresponding proportional resonant controllers to obtain the active and reactive compensation voltage components in the union reference axis coordinate system. Utilizing the high gain characteristic of the proportional resonant controller at a specific resonant frequency, it achieves zero steady-state error tracking control of each target subharmonic current. Then, a harmonic compensation voltage vector is generated based on the active and reactive power compensation voltage components, and superimposed with the fundamental control voltage vector to obtain a synthetic voltage reference vector. This achieves seamless integration of harmonic compensation control and fundamental control, ensuring the stability of the motor's fundamental operation and the effectiveness of harmonic suppression. Finally, harmonic suppression of the target motor is performed based on the synthetic voltage reference vector. The voltage command is converted into the actual motor drive signal through execution stages such as space vector modulation or direct torque control, completing the closed loop from control algorithm to physical execution.

[0008] Through the above technical solution, this application reduces the computational resources required for multi-harmonic coordinated control while ensuring the independent suppression accuracy of each target subharmonic. It solves the coupling interference problem between harmonic components caused by the inconsistency of coordinate systems in traditional parallel multi-harmonic controllers, and improves the harmonic suppression effect and dynamic response performance of permanent magnet synchronous motors under wide speed range operating conditions. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a flowchart illustrating the PMSM harmonic suppression method based on union vector projection reconstruction provided in this application embodiment; Figure 2 This is a schematic diagram of the PMSM harmonic suppression system based on union vector projection reconstruction provided in the embodiments of this application.

[0011] The components represented by each number in the attached diagram are explained below: The module includes a current information acquisition module 11, a current vector projection module 12, a compensation voltage acquisition module 13, a voltage vector generation module 14, and a harmonic suppression module 15. Detailed Implementation

[0012] This application provides a PMSM harmonic suppression method and system based on union vector projection reconstruction, which addresses the technical problems of high computational resource consumption and coupling interference between harmonic components in the existing multi-target independent control of subharmonics, which leads to a decrease in suppression accuracy.

[0013] Example 1, as Figure 1 As shown, embodiments of this application provide a PMSM harmonic suppression method based on union vector projection reconstruction, including: S10: Collect the multiphase stator current of the target motor, and perform harmonic separation on the multiphase stator current based on coordinate transformation to obtain the harmonic current vector corresponding to each target subharmonic. In this embodiment, the multiphase stator current of the target motor can be collected by a current sensor array. The current sensor array is installed at the output terminal of the stator winding of the motor or the DC bus side of the inverter. The sampling frequency is set to an integer multiple of the control frequency to ensure signal integrity. The collected analog current signal is converted into a digital quantity by an analog-to-digital converter and then enters the harmonic separation stage to obtain the harmonic current vector corresponding to each target harmonic.

[0014] Specifically, step S10 in the method includes: The multiphase stator current is transformed from the multiphase stationary coordinate system to the two-phase stationary coordinate system by coordinate transformation, and the current vector in the two-phase stationary coordinate system is obtained. For each target subharmonic, the current vector is rotated using the corresponding electric angular velocity to obtain the DC quantity of each target subharmonic component in the corresponding rotating coordinate system. The DC current is extracted by a low-pass filter and restored to the two-phase stationary coordinate system by inverse rotation coordinate transformation to obtain the harmonic current vector of each target subharmonic.

[0015] In this embodiment of the application, firstly, the three-phase stator current is transformed from the abc stationary coordinate system to the αβ two-phase stationary coordinate system through coordinate transformation to obtain the comprehensive current vector iαβ containing the fundamental wave and each harmonic component.

[0016] Secondly, for the k-th target harmonic, its rotating electrical angular velocity is kωe, where ωe is the fundamental electrical angular velocity. Construct a rotation matrix, for example, Tk(θk)=[cos(kθe) sin(kθe);-sin(kθe) cos(kθe)], and project iαβ onto the dkqk coordinate system rotating with kωe. In this rotating coordinate system, the k-th harmonic component is a DC component, while other frequency components are AC components. The DC component can be effectively extracted by a digital low-pass filter with a cutoff frequency much lower than kωe.

[0017] Subsequently, after inverse coordinate transformation Tk (-1)(θk) The extracted results are restored to the αβ coordinate system to obtain the harmonic current vector iαβ,k of the kth harmonic. By repeating the above process, the set of harmonic current vectors {iαβ,1,iαβ,2,...,iαβ,n} corresponding to all target harmonics can be obtained in parallel or serially.

[0018] S20: Construct a union reference axis and project the harmonic current vector onto the union reference axis to obtain the corresponding active current component and reactive current component; In this embodiment, the core of constructing the union reference axis lies in fusing the direction information of multiple target subharmonics into a unified reference coordinate framework, thereby avoiding the computational resource redundancy and coordinate system coupling problems caused by establishing independent rotating coordinate systems for each subharmonic in traditional methods.

[0019] Furthermore, the harmonic current vectors corresponding to each target subharmonic are projected onto the union reference axis to obtain the corresponding active current components and reactive current components.

[0020] The construction of the union reference axis includes: Obtain the amplitude and direction angle of the harmonic current vector for each target subharmonic; Using the amplitude as a weight, the direction angle of the harmonic current vector corresponding to each target subharmonic is weighted and vector synthesized to obtain the weighted synthesized direction angle; The union reference axis is constructed using the weighted composite direction angle as the main axis direction and the orthogonal direction of the main axis direction as the secondary axis direction.

[0021] In this embodiment, firstly, for each target harmonic, the amplitude |ik| and direction angle θk of its harmonic current vector are calculated, where the direction angle is defined as the angle between the harmonic current vector and the α-axis, and can be obtained through arctangent operation. Specifically, the arctangent operation is based on the components ikα and ikβ of each harmonic current vector in the αβ coordinate system, according to... The calculated amplitude is then determined according to... Calculated.

[0022] Subsequently, using the amplitude of each harmonic current vector as a weighting coefficient, the direction angles of all target subharmonics are weighted and averaged to calculate the weighted composite direction angle θΣ. The specific calculation formula is as follows: This weighted synthesis strategy ensures that harmonic components with larger amplitudes have a greater influence in the determination of the union reference axis direction, thereby enabling the union reference axis to adaptively point in the direction where the harmonic energy is most concentrated.

[0023] Furthermore, a two-dimensional orthogonal union reference axis coordinate system (dΣ, qΣ) is constructed with the weighted synthesis direction angle θΣ as the direction of the principal axis dΣ and θΣ+π / 2 as the direction of the secondary axis qΣ. This coordinate system is not a synchronous coordinate system that rotates with time, but a quasi-stationary coordinate system determined based on the instantaneous distribution characteristics of each harmonic vector in the current control cycle. Its direction is dynamically updated in each control cycle according to the real-time changes of the harmonic current vector, thus realizing adaptive tracking of the spatial distribution of multiple harmonic components.

[0024] Further, the harmonic current vector is projected onto the union reference axis to obtain the corresponding active current component and reactive current component, including: The harmonic current vectors corresponding to each target subharmonic are projected onto the principal axis direction and the secondary axis direction of the union reference axis, respectively. The projection scalar of the harmonic current vector in the principal axis direction is the corresponding active current component. The projection scalar of the harmonic current vector in the direction of the secondary axis is the corresponding reactive current component.

[0025] In this embodiment of the application, firstly, the harmonic current vectors iαβ,k corresponding to each target subharmonic are projected onto the principal axis dΣ direction and the secondary axis qΣ direction of the union reference axis, respectively. The projection transformation is achieved through inner product operation.

[0026] Specifically, for the k-th harmonic current vector iαβ,k=[ikα,ikβ]T, its projection scalar idΣ,k along the principal axis dΣ direction is as follows: The calculation shows that the projected scalar is the active current component corresponding to the kth harmonic.

[0027] The projection scalar iqΣ,k along the secondary axis qΣ direction according to The calculation shows that the projected scalar is the reactive current component corresponding to the kth harmonic.

[0028] It should be noted that the above projection operation transforms the harmonic current vectors that were originally distributed in different rotating coordinate systems into the union reference axis coordinate system, so that the active and reactive components of multiple target harmonics can be processed in parallel within the same coordinate frame.

[0029] S30: Input the active current component and the reactive current component into the corresponding proportional resonant controller, respectively, the active compensation voltage component and the reactive compensation voltage component in the union reference axis coordinate system; In this embodiment, the proportional resonant controller has an infinite gain characteristic at a specific resonant frequency, which enables zero steady-state error tracking control of sinusoidal AC signals. For the active current component idΣ,k and the reactive current component iqΣ,k in the union reference axis coordinate system, corresponding proportional resonant controllers are designed to adjust each target subharmonic current component.

[0030] Specifically, step S30 in the method includes: An independent proportional resonant controller is set for each target subharmonic, wherein the resonant frequency of each proportional resonant controller is set to the frequency of the corresponding target subharmonic; The active current component and the reactive current component corresponding to each target subharmonic are respectively used as input signals to the corresponding proportional resonant controller. The proportional resonant controller outputs the corresponding active power compensation voltage component and the reactive power compensation voltage component, respectively.

[0031] In this embodiment, firstly, an independent proportional resonant controller is configured for each target harmonic. The transfer function of the proportional resonant controller corresponding to the kth harmonic can be expressed as GPR,k(s)=Kp,k+Kr,k·s / (s2+(kωe)2), where Kp,k is the proportional gain coefficient, used to adjust the dynamic response speed of the system, and Kr,k is the resonant gain coefficient, used to determine the peak gain at the resonant frequency. The resonant frequency is precisely set to the electric angular velocity kωe of the corresponding target harmonic.

[0032] Subsequently, the active current component idΣ,k and reactive current component iqΣ,k corresponding to each target subharmonic are input as input signals to the corresponding proportional resonant controllers. The active current component is input to the d-axis proportional resonant controller GPR,d,k, and the reactive current component is input to the q-axis proportional resonant controller GPR,q,k. The parameters of the two controllers are designed according to the same criteria but are adjusted independently to adapt to the differences in dynamic characteristics between the active and reactive control channels.

[0033] Furthermore, the proportional resonant controller performs error calculations and compensation calculations on the input current component, and generates active compensation voltage component udΣ,k and reactive compensation voltage component uqΣ,k at the output terminal. The output voltage component represents the compensation voltage required to offset the kth harmonic current in the union reference axis coordinate system. Due to the infinite gain characteristic of the proportional resonant controller at the kωe frequency, even if there is a small current tracking error, the controller can generate sufficient voltage regulation to eliminate steady-state error and achieve zero steady-state error control.

[0034] S40: Generate a harmonic compensation voltage vector based on the active power compensation voltage component and the reactive power compensation voltage component, and superimpose it with the fundamental control voltage vector to obtain a composite voltage reference vector; In this embodiment, under the union reference axis coordinate system, the active power compensation voltage component and reactive power compensation voltage component corresponding to each target subharmonic have been calculated independently, converted into a unified voltage vector form and fused with the fundamental control voltage to form a complete motor drive control command.

[0035] Specifically, step S40 in the method includes: Using the main axis direction and the secondary axis direction of the union reference axis as a reference, the active power compensation voltage component and the reactive power compensation voltage component corresponding to each target subharmonic are transformed to the two-phase stationary coordinate system by back projection to obtain the harmonic compensation voltage vector corresponding to each target subharmonic. The harmonic compensation voltage vector corresponding to each target subharmonic is vector-sumped with the fundamental control voltage vector to obtain the synthesized voltage reference vector.

[0036] In this embodiment, firstly, using the principal axis direction dΣ and the secondary axis direction qΣ of the union reference axis as a reference, the active power compensation voltage component udΣ,k and reactive power compensation voltage component uqΣ,k corresponding to each target subharmonic are back-projected and transformed back to the αβ two-phase stationary coordinate system.

[0037] Specifically, for the kth harmonic, its harmonic compensation voltage vector uαβ,k=[ukα,ukβ]T is determined according to... and The calculation shows that the back projection operation realizes the inverse coordinate transformation from the union reference axis coordinate system to the stationary coordinate system, and recovers the direction information of each harmonic compensation voltage vector in the original space.

[0038] Subsequently, the harmonic compensation voltage vectors corresponding to all target subharmonics are vector-superimposed to obtain the total harmonic compensation voltage vector. This superposition process fully considers the amplitude and phase relationship of each harmonic compensation voltage, ensuring the synergistic effect of multi-harmonic compensation. Simultaneously, the fundamental control voltage vector uαβ,f generated by the fundamental control loop is obtained. This vector is typically calculated by the fundamental current loop proportional-integral controller or model predictive controller based on the deviation between the fundamental current reference command and the actual feedback, representing the voltage drive signal required to maintain the fundamental operation of the motor.

[0039] Finally, the total harmonic compensation voltage vector uαβ,h and the fundamental control voltage vector uαβ,f are summed to obtain the composite voltage reference vector, i.e. This synthesized vector simultaneously contains dual information on fundamental frequency operation control and harmonic suppression control, achieving seamless integration of the two control objectives at the voltage command level.

[0040] S50: Perform harmonic suppression on the target motor based on the synthesized voltage reference vector.

[0041] In this embodiment, the inverter's switching control signal is generated based on the synthesized voltage reference vector. That is, firstly, a matching synthesized voltage reference vector is obtained based on the synthesized voltage reference vector, and then a switching signal is generated in combination with the volt-second balance principle to drive the target motor to achieve harmonic suppression.

[0042] Specifically, step S50 in the method includes: Approximation calculation based on historical synthetic voltage reference vector; Based on the approximation calculation results, multiple matched and synthesized voltage reference vectors are obtained, and the output is the matching call result; Based on the matching call result, the action time of each matched synthetic voltage reference vector is calculated using the volt-second balance principle. Based on the available remaining time of the current control cycle, a switching signal is generated to drive the inverter to output voltage to the target motor.

[0043] In this embodiment, firstly, based on the approximation calculation of historical synthesized voltage reference vectors, the synthesized voltage reference vector uαβ,ref calculated in the current control cycle is similar to each vector in the pre-stored historical synthesized voltage reference vector database. The similarity measurement can employ Euclidean distance, cosine similarity, or a weighted comprehensive similarity index. For example, the Euclidean distance is calculated according to... Execution, cosine similarity is then performed according to The calculation involves selecting several historical vectors that have the highest similarity to the current synthetic voltage reference vector as candidate matching objects by setting a similarity threshold.

[0044] Subsequently, based on the approximation calculation results, the matching call selects multiple matching and synthesizing voltage reference vectors with the best similarity from the candidate matching objects, and outputs the matching call results. This process is implemented through a table lookup mechanism, which avoids complex real-time trigonometric function calculations and inverse transformation calculations, reducing the computational burden on the controller. The number of matching calls can be flexibly configured according to the trade-off between control accuracy and computational resources. Typically, three to five historical vectors with the highest similarity are selected to ensure the accuracy of voltage synthesis.

[0045] Next, based on the matching call results and the volt-second balance principle, the duration of each matched composite voltage reference vector is calculated. The volt-second balance principle requires that within one control cycle, the sum of the products of each basic voltage vector and its duration equals the product of the composite voltage reference vector and the control cycle. , where ui is the i-th matched synthetic voltage reference vector, Ti is its application time, and Ts is the control period. By solving this system of linear equations or using the space vector pulse width modulation algorithm, the optimal application time allocation scheme for each matched synthetic voltage reference vector can be obtained.

[0046] Finally, based on the remaining available time of the current control cycle, a switching signal is generated to drive the inverter to output voltage to the target motor. The generation of the switching signal needs to consider the inverter's dead time constraint, minimum pulse width limit, and switching loss optimization. The calculated action time is converted into the on / off sequence of each power switching device in the inverter. After being amplified by the drive circuit, the switching state of the insulated gate bipolar transistor or metal oxide semiconductor field-effect transistor is controlled, so that the inverter output terminal generates a composite voltage waveform containing the fundamental control voltage and harmonic compensation voltage. After this voltage waveform is injected into the motor stator winding, a compensation current opposite to the original harmonic current is generated, thereby achieving effective suppression of multiple target harmonics of the permanent magnet synchronous motor and improving the operating efficiency and electromagnetic compatibility performance of the motor system.

[0047] Furthermore, the PMSM harmonic suppression method based on union vector projection reconstruction also includes: Check if there is any unfinished overflow time in the previous control cycle; If it exists and is greater than zero, then the duration of the synthesized voltage reference vector of the previous control cycle is preferably defined as equal to the overflow time, and the available remaining time of the current control cycle is updated. If there is no overflow time or the overflow time is less than or equal to zero, then the available remaining time of the current control cycle is the total duration of the complete control cycle. Calculate the optimal synthetic voltage reference vector action time for the current cycle, and calculate the time compensation amount based on the harmonic compensation voltage vector. Add the optimal fundamental vector action time to the time compensation amount to obtain the total target action time. The total target duration is compared with the current available remaining time, and harmonic suppression of the target motor is performed based on the comparison result.

[0048] In this embodiment, firstly, it is detected whether there is any unfinished overflow time in the previous control cycle. This overflow time usually originates from the portion of the calculated synthetic voltage reference vector action time in the previous cycle that exceeds the total duration of the control cycle and is not fully executed, or from time truncation residue caused by physical limitations of the inverter switching devices. By reading the historical execution records in the controller's status register or memory buffer, the difference between the actual execution time and the theoretically calculated time of the previous cycle is obtained. If the difference is positive, it is determined that there is overflow time. .

[0049] Secondly, the overflow time Toverflow from the previous cycle is used as the voltage vector action time that needs to be compensated first in the current cycle. This compensation mechanism ensures the continuity and integrity of the voltage command, avoiding voltage waveform distortion or control interruption caused by cycle switching. Simultaneously, the available remaining time of the current control cycle is updated to... , where Ts is the total duration of the control cycle, and the remaining time will be used to accommodate the time allocation of the newly calculated synthetic voltage reference vector for the current cycle.

[0050] If there is no overflow time or the overflow time is less than or equal to zero, then the available remaining time of the current control cycle is the total duration of the complete control cycle, i.e. This indicates that the voltage command of the previous cycle has been fully executed, and the current cycle can start from zero to optimize the allocation of the action time.

[0051] Secondly, based on the motor operating status and harmonic current feedback detected in the current control cycle, the synthesized voltage reference vector uαβ,ref is recalculated, and the optimal action time allocation scheme of the reference vector is solved by the space vector modulation algorithm to obtain the optimal fundamental vector action time Tf,opt. The optimal fundamental vector action time refers to the duration for which the optimal voltage vector should be applied in the current control cycle so that the fundamental current tracks its reference value as accurately as possible.

[0052] Subsequently, the time compensation amount Th,comp is calculated based on the amplitude and phase characteristics of the harmonic compensation voltage vector uαβ,h. This compensation amount reflects the additional requirements of harmonic suppression control on switching time, for example, according to... An estimation is performed, where kh is the harmonic compensation weighting coefficient used to balance the priorities of fundamental wave control and harmonic suppression. The optimal fundamental wave vector action time is added to the time compensation amount to obtain the total target action time. .

[0053] Furthermore, the total target duration is compared with the current available remaining time. This comparison and decision-making mechanism enables dynamic optimization of the limited time resources within the control cycle, maximizing the harmonic suppression effect while ensuring the stability of the fundamental wave control. At the same time, the cross-cycle transmission of overflow time ensures the cumulative accuracy of voltage commands on multiple cycle scales.

[0054] Further, the total target action time is compared with the current available remaining time, and harmonic suppression of the target motor is performed based on the comparison result, including: If the total target action time is less than or equal to the available remaining time of the current cycle, the synthesized voltage reference vector is output within the current control cycle, and the action time is directly made equal to the total target action time. If the total target duration is greater than the available remaining time of the current cycle, the synthesized voltage reference vector is output within the current control cycle, and the duration is made equal to the available remaining time of the current cycle. The difference between the total target action time and the available remaining time is calculated as the overflow time of the current control cycle; Based on the switching state of the current control cycle of the synthesized voltage reference vector, and extracting the switching state of the previous control cycle, perform a Boolean logic OR operation to generate a union transition vector; The union transition vector and the overflow time are stored in a register for priority recall in the next control cycle.

[0055] In this embodiment, firstly, if the total target action time is less than or equal to the available remaining time of the current cycle, it indicates that the current control cycle has sufficient time resources to fully execute the synthesized voltage reference vector. At this time, the controller directly outputs the synthesized voltage reference vector within the current cycle and sets its actual action time to be equal to the total target action time. In this case, the voltage command does not need to be truncated or delayed, and the expected fundamental frequency control and harmonic compensation effects can be achieved.

[0056] If the total target duration exceeds the available remaining time in the current cycle, then the time resources in the current cycle are insufficient to support a complete voltage vector output. In this case, the controller still outputs the synthesized voltage reference vector, but limits its duration to the available remaining time in the current cycle. The unfinished portion will result in overflow time. This overflow time records the voltage demand that was not met in the current cycle and needs to be compensated for in subsequent cycles.

[0057] Subsequently, the difference between the total target action time and the available remaining time is calculated as the overflow time of the current control cycle. This calculation is implemented using existing hardware timers.

[0058] Furthermore, let the current cycle switching state vector be... The switching state vector of the previous cycle is Then the switching state corresponding to the union transition vector This operation ensures a smooth transition of the inverter's switching state during cycle switching, avoiding voltage spikes or current surges caused by state transitions.

[0059] Finally, the union transition vector and overflow time are stored in the controller's non-volatile register or cache for priority access in the next control cycle. This storage mechanism enables the cross-cycle transmission of control information, allowing the residual voltage command of the previous cycle to be executed first when the next cycle starts. This ensures the accuracy of voltage synthesis and the continuity of the motor current waveform on multiple cycle scales, ultimately achieving efficient suppression of multiple target subharmonics of the permanent magnet synchronous motor.

[0060] In summary, compared to existing technologies, this application achieves decoupling and coordinated control of multi-target harmonic compensation voltages by constructing a union reference axis coordinate system, avoiding resource redundancy and phase conflict problems caused by independent calculation of each harmonic in traditional methods. Through vector projection reconstruction technology, the compensation voltages of each harmonic are uniformly mapped to the union reference axis for amplitude optimization, and then restored to the stationary coordinate system via back projection transformation to achieve vector superposition, thus improving the accuracy and computational efficiency of multi-harmonic compensation.

[0061] In summary, the embodiments of this application have at least the following technical effects: This application provides a PMSM harmonic suppression method based on union vector projection reconstruction. First, it acquires the multiphase stator current of the target motor and performs harmonic separation based on coordinate transformation to obtain the harmonic current vector corresponding to each target subharmonic, achieving accurate extraction and independent characterization of each harmonic component in the multiphase current signal. Second, it constructs a union reference axis and projects the harmonic current vector onto this axis to obtain the corresponding active and reactive current components. A weighted vector synthesis strategy is used to fuse the direction information of multiple target subharmonics into a unified reference coordinate frame, reducing cross-coupling interference between harmonic components of different frequencies. Third, the active and reactive current components are input into the corresponding proportional resonant controllers to obtain the active and reactive compensation voltage components in the union reference axis coordinate system. Utilizing the high gain characteristic of the proportional resonant controller at a specific resonant frequency, it achieves zero steady-state error tracking control of each target subharmonic current. Then, a harmonic compensation voltage vector is generated based on the active and reactive power compensation voltage components, and superimposed with the fundamental control voltage vector to obtain a synthetic voltage reference vector. This achieves seamless integration of harmonic compensation control and fundamental control, ensuring the stability of the motor's fundamental operation and the effectiveness of harmonic suppression. Finally, harmonic suppression of the target motor is performed based on the synthetic voltage reference vector. The voltage command is converted into the actual motor drive signal through execution stages such as space vector modulation or direct torque control, completing the closed loop from control algorithm to physical execution.

[0062] Through the above technical solution, this application reduces the computational resources required for multi-harmonic coordinated control while ensuring the independent suppression accuracy of each target subharmonic. It solves the coupling interference problem between harmonic components caused by the inconsistency of coordinate systems in traditional parallel multi-harmonic controllers, and improves the harmonic suppression effect and dynamic response performance of permanent magnet synchronous motors under wide speed range operating conditions.

[0063] Example 2, as Figure 2 As shown, based on the same inventive concept as the PMSM harmonic suppression method based on union vector projection reconstruction provided in Embodiment 1, this application also provides a PMSM harmonic suppression system based on union vector projection reconstruction, including: The current information acquisition module 11 is used to acquire the multiphase stator current of the target motor and perform harmonic separation based on coordinate transformation on the multiphase stator current to obtain the harmonic current vector corresponding to each target subharmonic. The current vector projection module 12 is used to construct a union reference axis and project the harmonic current vector onto the union reference axis to obtain the corresponding active current component and reactive current component. The compensation voltage acquisition module 13 is used to input the active current component and the reactive current component into the corresponding proportional resonant controller respectively to acquire the active compensation voltage component and the reactive compensation voltage component in the union reference axis coordinate system. The voltage vector generation module 14 is used to generate a harmonic compensation voltage vector based on the active power compensation voltage component and the reactive power compensation voltage component, and to superimpose it with the fundamental control voltage vector to obtain a composite voltage reference vector. The harmonic suppression module 15 is used to suppress harmonics of the target motor according to the synthesized voltage reference vector.

[0064] In one embodiment, the current information acquisition module 11 is specifically used for: The multiphase stator current is transformed from the multiphase stationary coordinate system to the two-phase stationary coordinate system by coordinate transformation, and the current vector in the two-phase stationary coordinate system is obtained. For each target subharmonic, the current vector is rotated using the corresponding electric angular velocity to obtain the DC quantity of each target subharmonic component in the corresponding rotating coordinate system. The DC current is extracted by a low-pass filter and restored to the two-phase stationary coordinate system by inverse rotation coordinate transformation to obtain the harmonic current vector of each target subharmonic.

[0065] Furthermore, in one embodiment of the application, constructing the union set reference axis includes: Obtain the amplitude and direction angle of the harmonic current vector for each target subharmonic; Using the amplitude as a weight, the direction angle of the harmonic current vector corresponding to each target subharmonic is weighted and vector synthesized to obtain the weighted synthesized direction angle; The union reference axis is constructed using the weighted composite direction angle as the main axis direction and the orthogonal direction of the main axis direction as the secondary axis direction.

[0066] Further, the harmonic current vector is projected onto the union reference axis to obtain the corresponding active current component and reactive current component, including: The harmonic current vectors corresponding to each target subharmonic are projected onto the principal axis direction and the secondary axis direction of the union reference axis, respectively. The projection scalar of the harmonic current vector in the principal axis direction is the corresponding active current component. The projection scalar of the harmonic current vector in the direction of the secondary axis is the corresponding reactive current component.

[0067] In one embodiment, the compensation voltage acquisition module 13 is specifically used for: An independent proportional resonant controller is set for each target subharmonic, wherein the resonant frequency of each proportional resonant controller is set to the frequency of the corresponding target subharmonic; The active current component and the reactive current component corresponding to each target subharmonic are respectively used as input signals to the corresponding proportional resonant controller. The proportional resonant controller outputs the corresponding active power compensation voltage component and the reactive power compensation voltage component, respectively.

[0068] In one embodiment, the voltage vector generation module 14 is specifically used for: Using the main axis direction and the secondary axis direction of the union reference axis as a reference, the active power compensation voltage component and the reactive power compensation voltage component corresponding to each target subharmonic are transformed to the two-phase stationary coordinate system by back projection to obtain the harmonic compensation voltage vector corresponding to each target subharmonic. The harmonic compensation voltage vector corresponding to each target subharmonic is vector-sumped with the fundamental control voltage vector to obtain the synthesized voltage reference vector.

[0069] In one embodiment of the application, the harmonic suppression module 15 is specifically used for: Approximation calculation based on historical synthetic voltage reference vector; Based on the approximation calculation results, multiple matched and synthesized voltage reference vectors are obtained, and the output is the matching call result; Based on the matching call result, the action time of each matched synthetic voltage reference vector is calculated using the volt-second balance principle. Based on the available remaining time of the current control cycle, a switching signal is generated to drive the inverter to output voltage to the target motor.

[0070] Furthermore, the PMSM harmonic suppression method based on union vector projection reconstruction also includes: Check if there is any unfinished overflow time in the previous control cycle; If it exists and is greater than zero, then the duration of the synthesized voltage reference vector of the previous control cycle is preferably defined as equal to the overflow time, and the available remaining time of the current control cycle is updated. If there is no overflow time or the overflow time is less than or equal to zero, then the available remaining time of the current control cycle is the total duration of the complete control cycle. Calculate the optimal synthetic voltage reference vector action time for the current cycle, and calculate the time compensation amount based on the harmonic compensation voltage vector. Add the optimal fundamental vector action time to the time compensation amount to obtain the total target action time. The total target duration is compared with the current available remaining time, and harmonic suppression of the target motor is performed based on the comparison result.

[0071] Further, the total target action time is compared with the current available remaining time, and harmonic suppression of the target motor is performed based on the comparison result, including: If the total target action time is less than or equal to the available remaining time of the current cycle, the synthesized voltage reference vector is output within the current control cycle, and the action time is directly made equal to the total target action time. If the total target duration is greater than the available remaining time of the current cycle, the synthesized voltage reference vector is output within the current control cycle, and the duration is made equal to the available remaining time of the current cycle. The difference between the total target action time and the available remaining time is calculated as the overflow time of the current control cycle; Based on the switching state of the current control cycle of the synthesized voltage reference vector, and extracting the switching state of the previous control cycle, perform a Boolean logic OR operation to generate a union transition vector; The union transition vector and the overflow time are stored in a register for priority recall in the next control cycle.

Claims

1. A PMSM harmonic suppression method based on union vector projection reconstruction, characterized in that, include: The multiphase stator current of the target motor is collected, and harmonic separation based on coordinate transformation is performed on the multiphase stator current to obtain the harmonic current vector corresponding to each target subharmonic. Construct a union reference axis and project the harmonic current vector onto the union reference axis to obtain the corresponding active current component and reactive current component; The active current component and the reactive current component are respectively input into the corresponding proportional resonant controller to obtain the active compensation voltage component and the reactive compensation voltage component in the union reference axis coordinate system. Based on the active power compensation voltage component and the reactive power compensation voltage component, a harmonic compensation voltage vector is generated, and superimposed with the fundamental control voltage vector to obtain a composite voltage reference vector. Harmonic suppression of the target motor is performed based on the synthesized voltage reference vector.

2. The PMSM harmonic suppression method based on union vector projection reconstruction as described in claim 1, characterized in that, The multiphase stator current of the target motor is acquired, and harmonic separation based on coordinate transformation is performed on the multiphase stator current to obtain the harmonic current vector corresponding to the target subharmonic, including: The multiphase stator current is transformed from the multiphase stationary coordinate system to the two-phase stationary coordinate system by coordinate transformation, and the current vector in the two-phase stationary coordinate system is obtained. For each target subharmonic, the current vector is rotated using the corresponding electric angular velocity to obtain the DC quantity of each target subharmonic component in the corresponding rotating coordinate system. The DC current is extracted by a low-pass filter and restored to the two-phase stationary coordinate system by inverse rotation coordinate transformation to obtain the harmonic current vector of each target subharmonic.

3. The PMSM harmonic suppression method based on union vector projection reconstruction as described in claim 1, characterized in that, Constructing a union reference axis includes: Obtain the amplitude and direction angle of the harmonic current vector for each target subharmonic; Using the amplitude as a weight, the direction angle of the harmonic current vector corresponding to each target subharmonic is weighted and vector synthesized to obtain the weighted synthesized direction angle; The union reference axis is constructed using the weighted composite direction angle as the main axis direction and the orthogonal direction of the main axis direction as the secondary axis direction.

4. The PMSM harmonic suppression method based on union vector projection reconstruction as described in claim 1, characterized in that, Projecting the harmonic current vector onto the union reference axis to obtain the corresponding active current component and reactive current component includes: The harmonic current vectors corresponding to each target subharmonic are projected onto the principal axis direction and the secondary axis direction of the union reference axis, respectively. The projection scalar of the harmonic current vector in the principal axis direction is the corresponding active current component. The projection scalar of the harmonic current vector in the direction of the secondary axis is the corresponding reactive current component.

5. The PMSM harmonic suppression method based on union vector projection reconstruction as described in claim 1, characterized in that, The active current component and the reactive current component are respectively input to the corresponding proportional resonant controller. The active compensation voltage component and the reactive compensation voltage component in the union reference axis coordinate system include: An independent proportional resonant controller is set for each target subharmonic, wherein the resonant frequency of each proportional resonant controller is set to the frequency of the corresponding target subharmonic; The active current component and the reactive current component corresponding to each target subharmonic are respectively used as input signals to the corresponding proportional resonant controller. The proportional resonant controller outputs the corresponding active power compensation voltage component and the reactive power compensation voltage component, respectively.

6. The PMSM harmonic suppression method based on union vector projection reconstruction as described in claim 1, characterized in that, Based on the active power compensation voltage component and the reactive power compensation voltage component, a harmonic compensation voltage vector is generated, and the harmonic compensation voltage vector is superimposed with the fundamental control voltage vector to obtain a composite voltage reference vector, including: Using the main axis direction and the secondary axis direction of the union reference axis as a reference, the active power compensation voltage component and the reactive power compensation voltage component corresponding to each target subharmonic are transformed to the two-phase stationary coordinate system by back projection to obtain the harmonic compensation voltage vector corresponding to each target subharmonic. The harmonic compensation voltage vector corresponding to each target subharmonic is vector-sumped with the fundamental control voltage vector to obtain the synthesized voltage reference vector.

7. The PMSM harmonic suppression method based on union vector projection reconstruction as described in claim 1, characterized in that, Harmonic suppression of the target motor based on the synthesized voltage reference vector includes: Approximation calculation based on historical synthetic voltage reference vector; Based on the approximation calculation results, multiple matched and synthesized voltage reference vectors are obtained, and the output is the matching call result; Based on the matching call result, the action time of each matched synthetic voltage reference vector is calculated using the volt-second balance principle. Based on the available remaining time of the current control cycle, a switching signal is generated to drive the inverter to output voltage to the target motor.

8. The PMSM harmonic suppression method based on union vector projection reconstruction as described in claim 1, characterized in that, Also includes: Check if there is any unfinished overflow time in the previous control cycle; If it exists and is greater than zero, then the duration of the synthesized voltage reference vector of the previous control cycle is preferably defined as equal to the overflow time, and the available remaining time of the current control cycle is updated. If there is no overflow time or the overflow time is less than or equal to zero, then the available remaining time of the current control cycle is the total duration of the complete control cycle. Calculate the optimal synthetic voltage reference vector action time for the current cycle, and calculate the time compensation amount based on the harmonic compensation voltage vector. Add the optimal fundamental vector action time to the time compensation amount to obtain the total target action time. The total target duration is compared with the current available remaining time, and harmonic suppression of the target motor is performed based on the comparison result.

9. The PMSM harmonic suppression method based on union vector projection reconstruction as described in claim 8, characterized in that, The total target duration is compared with the current available remaining time, and harmonic suppression of the target motor is performed based on the comparison result, including: If the total target action time is less than or equal to the available remaining time of the current cycle, the synthesized voltage reference vector is output within the current control cycle, and the action time is directly made equal to the total target action time. If the total target duration is greater than the available remaining time of the current cycle, the synthesized voltage reference vector is output within the current control cycle, and the duration is made equal to the available remaining time of the current cycle. The difference between the total target action time and the available remaining time is calculated as the overflow time of the current control cycle; Based on the switching state of the current control cycle of the synthesized voltage reference vector, and extracting the switching state of the previous control cycle, perform a Boolean logic OR operation to generate a union transition vector; The union transition vector and the overflow time are stored in a register for priority recall in the next control cycle.

10. A PMSM harmonic suppression system based on union vector projection reconstruction, characterized in that, The PMSM harmonic suppression method based on union vector projection reconstruction as described in any one of claims 1-9 includes: The current information acquisition module is used to acquire the multiphase stator current of the target motor and perform harmonic separation based on coordinate transformation on the multiphase stator current to obtain the harmonic current vector corresponding to each target subharmonic. The current vector projection module is used to construct a union reference axis and project the harmonic current vector onto the union reference axis to obtain the corresponding active current component and reactive current component. The compensation voltage acquisition module is used to input the active current component and the reactive current component into the corresponding proportional resonant controller respectively, and acquire the active compensation voltage component and the reactive compensation voltage component in the union reference axis coordinate system. The voltage vector generation module is used to generate a harmonic compensation voltage vector based on the active power compensation voltage component and the reactive power compensation voltage component, and to superimpose it with the fundamental control voltage vector to obtain a composite voltage reference vector. The harmonic suppression module is used to suppress harmonics in the target motor based on the synthesized voltage reference vector.

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