Harmonic suppression method and device, permanent magnet synchronous motor and storage medium

Abstract

The invention discloses a harmonic suppression method and device, a permanent magnet synchronous motor and a storage medium, and relates to the technical field of motor control, and the harmonic suppression method is applied to the permanent magnet synchronous motor, and comprises the steps: carrying out the harmonic extraction of a stator current of the permanent magnet synchronous motor, and obtaining a fifth harmonic current component of the stator current; determining the quintuple harmonic voltage compensation amount of the stator current according to the quintuple harmonic current component of the stator current; and performing voltage feed-forward compensation on the permanent magnet synchronous motor based on the quintuple harmonic voltage compensation amount of the stator current. On the basis of ensuring that the influence of the higher harmonic current generated in the operation process of the permanent magnet synchronous motor on the rotating speed and the torque of the motor is controlled within an acceptable range, the engineering realization difficulty is effectively reduced.

Description

Technical Field

[0001] The present application relates to the field of motor control technology, and in particular to a harmonic suppression method, device, permanent magnet synchronous motor and storage medium. Background Art

[0002] Permanent Magnet Synchronous Motor (PMSM), as a type of high-efficiency and energy-saving motor, has been widely used in many industries such as chemical industry, light industry and textile, and household appliances due to its superior high torque ratio, high power density, sturdy structure and excellent controllability.

[0003] Since permanent magnet synchronous motors generate high-order harmonic currents during operation, causing motor speed and torque pulsation, a suppression method based on harmonic injection is proposed in the relevant technology to perform feedforward compensation on the motor to suppress harmonic currents.

[0004] However, this method requires the use of high-order filters to accurately extract harmonic currents of different frequencies, and also requires the calculation of the corresponding harmonic voltage compensation through an advanced controller, which makes engineering implementation difficult. Summary of the invention

[0005] The main purpose of this application is to provide a harmonic suppression method, device, permanent magnet synchronous motor and storage medium, aiming to reduce the impact of high-order harmonic currents on the motor while reducing the difficulty of engineering implementation.

[0006] To achieve the above object, the present application provides a harmonic suppression method, which is applied to a permanent magnet synchronous motor, and the method comprises:

[0007] Performing harmonic extraction on the stator current of the permanent magnet synchronous motor to obtain the fifth harmonic current component of the stator current;

[0008] Determining a fifth harmonic voltage compensation amount of the stator current according to a fifth harmonic current component of the stator current;

[0009] Based on the fifth harmonic voltage compensation amount of the stator current, voltage feedforward compensation is performed on the permanent magnet synchronous motor.

[0010] In one embodiment, the permanent magnet synchronous motor includes a sampling resistor, and the step of performing harmonic extraction on the stator current of the permanent magnet synchronous motor to obtain the fifth harmonic current component of the stator current includes:

[0011] Acquiring the stator current of the permanent magnet synchronous motor in a three-phase stationary coordinate system by sampling the sampling resistor;

[0012] Performing Clarke transformation on the stator current of the permanent magnet synchronous motor in a three-phase stationary coordinate system to obtain the stator current of the permanent magnet synchronous motor in a two-phase stationary coordinate system;

[0013] Performing a Park transformation on the stator current of the permanent magnet synchronous motor in a two-phase stationary coordinate system to obtain the stator current of the permanent magnet synchronous motor in a two-phase rotating coordinate system;

[0014] Harmonics of the stator current of the permanent magnet synchronous motor in a two-phase rotating coordinate system are extracted by first-order bandpass filtering to obtain the fifth harmonic current component of the stator current in the two-phase rotating coordinate system.

[0015] In one embodiment, the step of determining the fifth harmonic voltage compensation amount of the stator current according to the fifth harmonic current component of the stator current comprises:

[0016] Determining a fifth harmonic voltage compensation amount of the stator current in the two-phase rotating coordinate system according to the fifth harmonic current component of the stator current in the two-phase rotating coordinate system;

[0017] The fifth harmonic voltage compensation amount of the stator current in the two-phase rotating coordinate system is subjected to an inverse Park transformation to obtain the fifth harmonic voltage compensation amount of the stator current in the two-phase stationary coordinate system.

[0018] In one embodiment, the fifth harmonic current component of the stator current in the two-phase rotating coordinate system includes a first straight-axis fifth harmonic current component and a first quadrature-axis fifth harmonic current component, and the fifth harmonic voltage compensation amount of the stator current in the two-phase rotating coordinate system includes a first straight-axis fifth harmonic voltage compensation amount and a first quadrature-axis fifth harmonic voltage compensation amount;

[0019] The step of determining the fifth harmonic voltage compensation amount of the stator current in the two-phase rotating coordinate system according to the fifth harmonic current component of the stator current in the two-phase rotating coordinate system comprises:

[0020] Obtaining the stator resistance, direct-axis inductance, quadrature-axis inductance and motor speed of the permanent magnet synchronous motor;

[0021] Substituting the stator resistance, direct-axis inductance, motor speed, and the first direct-axis fifth harmonic current component of the permanent magnet synchronous motor into a preset first direct-axis fifth harmonic voltage compensation amount calculation formula for calculation, to obtain the first direct-axis fifth harmonic voltage compensation amount;

[0022] Substituting the stator resistance, quadrature-axis inductance, motor speed, and the first quadrature-axis fifth harmonic current component of the permanent magnet synchronous motor into a preset first quadrature-axis fifth harmonic voltage compensation amount calculation formula for calculation, to obtain the first quadrature-axis fifth harmonic voltage compensation amount;

[0023] Among them, the calculation formula of the first direct axis fifth harmonic voltage compensation amount is:

[0024]

[0025] The calculation formula of the fifth harmonic voltage compensation amount of the first quadrature axis is:

[0026]

[0027] in, is the compensation value of the fifth harmonic voltage of the first straight axis, is the compensation value of the fifth harmonic voltage of the first quadrature axis, R is the stator resistance, is the fifth harmonic current component of the first straight axis, is the fifth harmonic current component of the first quadrature axis, Ld is the direct axis inductance, Lq is the quadrature axis inductance, is the motor speed.

[0028] In one embodiment, the permanent magnet synchronous motor includes a sampling resistor, and the step of performing harmonic extraction on the stator current of the permanent magnet synchronous motor to obtain the fifth harmonic current component of the stator current includes:

[0029] Acquiring the stator current of the permanent magnet synchronous motor in a three-phase stationary coordinate system by sampling the sampling resistor;

[0030] The stator current of the permanent magnet synchronous motor in the three-phase stationary coordinate system is transformed into the five-order two-phase rotating coordinate system to obtain the stator current of the permanent magnet synchronous motor in the five-order two-phase rotating coordinate system, wherein the rotation frequency of the five-order two-phase rotating coordinate system is five times the base frequency;

[0031] Harmonics of the stator current of the permanent magnet synchronous motor in a fifth-order two-phase rotating coordinate system are extracted by first-order low-pass filtering to obtain a fifth harmonic current component of the stator current in the fifth-order two-phase rotating coordinate system.

[0032] In one embodiment, the fifth harmonic voltage compensation amount of the stator current is determined according to the fifth harmonic current component of the stator current;

[0033] Determining a fifth harmonic voltage compensation amount of the stator current in a fifth two-phase rotating coordinate system according to a fifth harmonic current component of the stator current in a fifth two-phase rotating coordinate system;

[0034] The fifth harmonic voltage compensation amount of the stator current in the fifth two-phase rotating coordinate system is transformed into the two-phase stationary coordinate system to obtain the fifth harmonic voltage compensation amount of the stator current in the two-phase stationary coordinate system.

[0035] In one embodiment, the fifth harmonic current component of the stator current in the fifth two-phase rotating coordinate system includes a second direct-axis fifth harmonic current component and a second quadrature-axis fifth harmonic current component, and the fifth harmonic voltage compensation amount of the stator current in the fifth two-phase rotating coordinate system includes a second direct-axis fifth harmonic voltage compensation amount and a second quadrature-axis fifth harmonic voltage compensation amount;

[0036] The step of determining the fifth harmonic voltage compensation amount of the stator current in the fifth two-phase rotating coordinate system according to the fifth harmonic current component of the stator current in the fifth two-phase rotating coordinate system comprises:

[0037] Obtaining the stator resistance, direct-axis inductance, quadrature-axis inductance and motor speed of the permanent magnet synchronous motor;

[0038] Substituting the stator resistance, direct-axis inductance, motor speed, and the second direct-axis fifth harmonic current component of the permanent magnet synchronous motor into a preset second direct-axis fifth harmonic voltage compensation amount calculation formula for calculation, to obtain the second direct-axis fifth harmonic voltage compensation amount;

[0039] Substituting the stator resistance, quadrature-axis inductance, motor speed, and the second quadrature-axis fifth harmonic current component of the permanent magnet synchronous motor into a preset second quadrature-axis fifth harmonic voltage compensation amount calculation formula for calculation, to obtain the second quadrature-axis fifth harmonic voltage compensation amount;

[0040] Among them, the calculation formula of the second direct axis fifth harmonic voltage compensation amount is:

[0041]

[0042] The calculation formula of the fifth harmonic voltage compensation amount of the second quadrature axis is:

[0043]

[0044] in, is the compensation value of the second direct axis fifth harmonic voltage, is the compensation value of the fifth harmonic voltage of the second quadrature axis, R is the stator resistance, is the second direct axis fifth harmonic current component, is the second quadrature axis fifth harmonic current component, Ld is the direct axis inductance, Lq is the quadrature axis inductance, is the motor speed.

[0045] In addition, to achieve the above-mentioned purpose, the present application also provides a harmonic suppression device, which is applied to a permanent magnet synchronous motor, and the device includes:

[0046] A harmonic current extraction module, used for performing harmonic extraction on the stator current of the permanent magnet synchronous motor to obtain the fifth harmonic current component of the stator current;

[0047] A harmonic compensation calculation module, used to determine the fifth harmonic voltage compensation amount of the stator current according to the fifth harmonic current component of the stator current;

[0048] A voltage feedforward compensation module is used to perform voltage feedforward compensation on the permanent magnet synchronous motor based on the fifth harmonic voltage compensation amount of the stator current.

[0049] In addition, to achieve the above-mentioned objectives, the present application also provides a permanent magnet synchronous motor, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the harmonic suppression method as described above.

[0050] In addition, to achieve the above objectives, the present application also proposes a storage medium, which is a computer-readable storage medium, and stores a computer program on the storage medium. When the computer program is executed by a processor, the steps of the harmonic suppression method described above are implemented.

[0051] The present application provides a harmonic suppression method, which is applied to a permanent magnet synchronous motor. The present application obtains the fifth harmonic current component of the stator current by performing harmonic extraction on the stator current of the permanent magnet synchronous motor; determines the fifth harmonic voltage compensation amount of the stator current according to the fifth harmonic current component of the stator current; and performs voltage feedforward compensation on the permanent magnet synchronous motor based on the fifth harmonic voltage compensation amount of the stator current. The present application only considers the fifth harmonic component that has the greatest impact on the motor speed and torque when extracting the harmonic current and calculating the harmonic voltage compensation amount, thereby effectively reducing the difficulty of engineering implementation while ensuring that the impact of the high-order harmonic current generated during the operation of the permanent magnet synchronous motor on the motor speed and torque is controlled within an acceptable range. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0053] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0054] Figure 1A schematic diagram of a flow chart provided for the first embodiment of the harmonic suppression method of the present application;

[0055] Figure 2 This is a schematic diagram of the extraction process of the fifth harmonic current in the second embodiment of the harmonic suppression method of the present application;

[0056] Figure 3 This is a schematic diagram of the extraction process of the fifth harmonic current in the third embodiment of the harmonic suppression method of the present application;

[0057] Figure 4 This is a schematic diagram of the module structure of the harmonic suppression device according to an embodiment of the present application;

[0058] Figure 5 Schematic diagram of the device structure of the hardware operating environment involved in the harmonic suppression method in the embodiment of the present application.

[0059] The purpose, features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0060] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0061] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0062] Those skilled in the art will know that permanent magnet synchronous motors will generate high-order harmonic currents during operation. This is because the motor drive usually uses a power electronic inverter, and in the process of converting DC power into AC power, the inverter introduces a non-sinusoidal waveform into the output current due to the non-ideal switching characteristics of the switching device, which directly leads to the generation of harmonics. Especially during the "dead zone" time of the inverter, the non-conducting interval set to prevent the upper and lower bridge arms from directly connecting will cause a gap in the output voltage or current, further exacerbating the harmonic phenomenon.

[0063] In addition, the back electromotive force waveform generated by the permanent magnet synchronous motor during rotation is not completely sinusoidal, especially in high magnetic permeability materials and high magnetic flux density, the back electromotive force may contain significant harmonic components. These harmonics interact with the fundamental current output by the inverter and further generate current harmonics through the nonlinear characteristics of the motor.

[0064] High-order harmonic currents will generate non-sinusoidal magnetomotive force in permanent magnet synchronous motors, which will interact with the main magnetic field of the motor, resulting in non-uniformity and asymmetry of the air gap magnetic field of the motor, thereby generating torque pulsation. Torque pulsation will reduce the smoothness of the motor's operation and affect its ability to drive the load. Although it usually does not directly affect the basic speed setting of the motor, it will reduce the effective output torque and affect the dynamic response and control accuracy.

[0065] At the same time, harmonic currents generate additional losses in the motor windings, including copper losses (losses on wire resistance) and iron losses (hysteresis losses and eddy current losses). These losses lead to a decrease in the overall efficiency of the motor and a relative reduction in torque output, especially at low speeds and high loads. This is because the efficiency of the motor itself is not high at this time, and the impact of harmonic losses is more significant. Additional losses will also be converted into heat energy, causing the temperature of the motor windings and core to rise. Long-term operation may accelerate the aging of insulation materials, shorten the service life of the motor, and may trigger overheating protection, limiting the motor's continuous output capacity, indirectly affecting the ability to maintain a constant speed.

[0066] Therefore, a suppression method based on harmonic injection is proposed in the related art. The high-order harmonic currents generated during the operation of the permanent magnet synchronous motor are accurately extracted through advanced filters to separate the harmonic currents of all frequencies, and the extracted harmonic signals are analyzed through complex control algorithms or advanced controllers (such as adaptive controllers, fuzzy controllers, or algorithms based on model predictive control, etc.), and the amplitude and phase of the harmonic voltage to be compensated (that is, the harmonic voltage compensation amount) are calculated. The corresponding harmonic voltage signal is generated according to the calculated harmonic voltage compensation amount, and feedforward control is applied in the control link of the inverter, that is, the harmonic compensation voltage is superimposed on the fundamental voltage instruction, so that the total voltage output by the inverter includes both the fundamental voltage required to drive the motor and the compensation voltage used to offset the harmonic current. This compensation mechanism is designed to offset the harmonic currents generated in the motor in real time and accurately, reducing the impact of harmonics on motor performance and grid quality.

[0067] The advantage of this approach is its initiative and precision. In theory, it can significantly improve the overall efficiency and stability of power electronic devices and motor systems, reduce heat generation, and improve operating quality. However, implementing this strategy requires highly accurate control algorithms and high-performance hardware support to ensure real-time and accuracy. In addition, the increased complexity of the control system places higher demands on the design, debugging, and implementation of the algorithm.

[0068] This method is very beneficial for equipment that requires precise control because it can significantly reduce torque ripple, reduce noise, and improve operating efficiency and stability, especially in the fields of precision machining, aerospace, and high-end manufacturing. By actively suppressing harmonics, the equipment can achieve smoother operating characteristics and extend its service life while reducing energy consumption and electromagnetic interference, meeting the design requirements of high-performance systems.

[0069] However, most industrial or household motor equipment does not require such high control accuracy. In these applications, cost-effectiveness, reliability and ease of maintenance are often more important than extreme performance optimization. In this case, we need a harmonic suppression method for motors with lower precision control requirements, which can control the impact of high-order harmonic currents generated by permanent magnet synchronous motors during operation on motor speed and torque within an acceptable range, while greatly reducing the difficulty of engineering implementation and making harmonic suppression simpler and easier to implement.

[0070] Based on this, an embodiment of the present application proposes a harmonic suppression method applied to a permanent magnet synchronous motor, and the main solution is: perform harmonic extraction on the stator current of the permanent magnet synchronous motor to obtain the fifth harmonic current component of the stator current; determine the fifth harmonic voltage compensation amount of the stator current based on the fifth harmonic current component of the stator current; and perform voltage feedforward compensation on the permanent magnet synchronous motor based on the fifth harmonic voltage compensation amount of the stator current.

[0071] This application effectively reduces the difficulty of engineering implementation by considering only the fifth harmonic component that has the greatest impact on the motor speed and torque when extracting harmonic currents and calculating harmonic voltage compensation amounts. This ensures that the impact of high-order harmonic currents generated during the operation of the permanent magnet synchronous motor on the motor speed and torque is controlled within an acceptable range.

[0072] Embodiment 1

[0073] Please refer to Figure 1 , Figure 1 A schematic diagram of the flow chart of the first embodiment of the harmonic suppression method of the present application.

[0074] It should be noted that the execution subject of this embodiment may be a permanent magnet synchronous motor, or a control device that is independent of the permanent magnet synchronous motor and is in communication connection with the permanent magnet synchronous motor. The following takes the permanent magnet synchronous motor as an example to illustrate this embodiment and the following embodiments.

[0075] In this embodiment, the harmonic suppression method is applied to a permanent magnet synchronous motor, and the method includes steps S100 to S300:

[0076] Step S100, performing harmonic extraction on the stator current of the permanent magnet synchronous motor to obtain the fifth harmonic current component of the stator current;

[0077] It should be noted that in a permanent magnet synchronous motor, the stator is the fixed part of the motor, in which the three-phase winding is embedded, and the stator current refers to the current provided to the stator winding through the inverter in the permanent magnet synchronous motor. Since the stator current is a parameter that can be directly measured and adjusted in the permanent magnet synchronous motor, when extracting the harmonic current of the permanent magnet synchronous motor, the harmonic extraction is generally performed on the stator current.

[0078] In addition, it should be noted that harmonic extraction refers to the process of identifying and separating a single frequency component from a complex electrical signal, especially those frequency components that are higher than integer multiples of the fundamental frequency, i.e., higher harmonics. Harmonic extraction is an important technical link in the fields of power systems, signal processing, acoustic analysis, etc. This process usually involves three steps: signal analysis, harmonic identification, and filtering. Among them, signal analysis refers to analyzing the original signal to understand the frequency components it contains. This can be achieved through time domain analysis or frequency domain analysis. The latter usually uses Fourier transform or fast Fourier transform to convert the time domain signal into a spectrum diagram to show the amplitude and phase of different frequency components. Harmonic identification refers to identifying which frequency components belong to harmonics based on spectrum analysis. Harmonics are usually integer multiples of the fundamental frequency, for example, the second harmonic of a 50 Hz fundamental wave is 100 Hz, the third harmonic is 160 Hz, etc. Filtering can use different filters to extract or separate these harmonic components. Commonly used filters include low-pass filters, high-pass filters, band-pass filters, and band-stop filters. For harmonic extraction, a bandpass filter or low-pass filter may be used to selectively pass specific harmonic frequencies. In addition to traditional filtering methods, adaptive filtering, wavelet transform, digital signal processor algorithms, or software-based algorithms (such as function programming in MATLAB, Matrix Laboratory) can also be used to accurately extract harmonic components.

[0079] In this embodiment, the dead zone effect and magnetic circuit magnetic saturation effect of the permanent magnet synchronous motor will significantly increase the content of the fifth harmonic current, and the fifth harmonic current has a characteristic phase relationship with the fundamental wave, which can significantly affect the electromagnetic torque of the motor, resulting in an aggravation of the nonlinear effect, that is, among all the high-order harmonic currents generated by the permanent magnet synchronous motor during operation, the fifth harmonic current is the harmonic current that has the greatest impact on the motor speed and torque pulsation, while the harmonic current components of other frequencies have little impact on the motor speed and torque, or even basically no impact. Therefore, this embodiment only extracts the fifth harmonic current component in the stator current, and does not process the harmonic current components of other frequencies, which effectively reduces the workload and difficulty of harmonic extraction. Compared with the method of accurately extracting harmonic currents of all frequencies in the related art, this embodiment is simpler and easier to implement, and is more suitable for general industrial or household motor equipment.

[0080] In addition, it should be specially explained that, in the present embodiment, performing harmonic extraction on the stator current actually refers to performing harmonic extraction on the measured stator current signal, thereby obtaining the fifth harmonic current component in the stator current signal, and then calculating the corresponding fifth harmonic voltage compensation amount, performing feed-forward voltage compensation on the permanent magnet synchronous motor, so as to suppress the fifth harmonic current in the stator current.

[0081] Step S200, determining a fifth harmonic voltage compensation amount of the stator current according to the fifth harmonic current component of the stator current;

[0082] It should be noted that according to Kirchhoff's law and circuit theory, voltage and current follow similar mathematical relationships in the frequency domain. When there is a nonlinear load in the system (such as a permanent magnet synchronous motor under inverter power supply conditions), the harmonic components in the current reflect the influence of voltage harmonics and the characteristics of the load itself. Therefore, the fifth harmonic voltage component corresponding to the fifth harmonic current component can be determined based on the fifth harmonic current component extracted from the stator current, and the harmonic voltage compensation amount is equal to the fifth harmonic voltage component in magnitude and opposite in direction.

[0083] Therefore, when calculating the fifth harmonic voltage compensation amount according to the fifth harmonic current component, the impedance (including resistance, inductance, etc.) of the permanent magnet synchronous motor at the fifth harmonic frequency can be measured in advance and calculated using Ohm's law. Compared with the method that relies on complex control algorithms or advanced controllers in the related art, this embodiment does not need to use expensive advanced controllers or complex software algorithms, effectively reducing the cost of the motor, avoiding the complexity of real-time iterative calculation or model predictive control, making the system design and implementation simpler and faster, the calculation process simpler, and the difficulty of engineering implementation greatly reduced. At the same time, the impedance value of the predicted amount is static data, which reduces the compensation error caused by inaccurate dynamic impedance estimation. Especially when the system parameters do not change much or the operating environment is relatively stable, the compensation scheme based on the fixed impedance value in this embodiment can provide a stable harmonic suppression effect and enhance the reliability and robustness of the system.

[0084] In addition, the system structure of this embodiment is simple and clear, and maintenance personnel can understand and debug it more easily. When troubleshooting, the accuracy of impedance measurement or the performance of compensation circuit can be directly checked without in-depth analysis of complex control logic. After detecting that the impedance of the motor has changed, there is no need to perform complex parameter setting, which makes adjustment more convenient and more suitable for motor equipment that does not require high control accuracy.

[0085] Step S300: performing voltage feed-forward compensation on the permanent magnet synchronous motor based on the fifth harmonic voltage compensation amount of the stator current.

[0086] It should be noted that voltage feedforward compensation refers to generating a corresponding harmonic voltage compensation signal or harmonic voltage compensation instruction based on the calculated harmonic voltage compensation amount and superimposing it on the control signal of the inverter, so as to compensate for the harmonic current to be generated in advance without going through the feedback link of the system. In this way, when the inverter generates the voltage waveform to drive the motor, it will actively include a component to offset the influence of harmonics. This method of feedforward compensation does not rely on system feedback, can respond to harmonic currents more quickly, can directly compensate for specific harmonics, effectively reduce harmonic currents, improve power quality, and thus reduce torque pulsation and noise, and improve motor operating efficiency and stability.

[0087] This embodiment only considers the fifth harmonic component that has the greatest impact on the motor speed and torque when extracting harmonic current and calculating harmonic voltage compensation, thereby effectively reducing the difficulty of engineering implementation and ensuring that the impact of high-order harmonic currents generated during the operation of the permanent magnet synchronous motor on the motor speed and torque is controlled within an acceptable range.

[0088] Embodiment 2

[0089] Please refer to Figure 2 , Figure 2This is a schematic diagram of the extraction process of the fifth harmonic current in the second embodiment of the harmonic suppression method of the present application.

[0090] In a feasible implementation manner, the permanent magnet synchronous motor includes a sampling resistor, and step S100 may include steps S110 to S140:

[0091] Step S110, acquiring the stator current of the permanent magnet synchronous motor in a three-phase stationary coordinate system by sampling with the sampling resistor;

[0092] In this embodiment, a sampling resistor is provided on the permanent magnet synchronous motor for sampling and obtaining the stator current in a three-phase stationary coordinate system. The sampling resistor is generally provided at the input end of the stator winding, the output end of the inverter or the circuit between the stator winding and the inverter. This embodiment does not make any specific limitation on this.

[0093] Step S120, performing Clarke transformation on the stator current of the permanent magnet synchronous motor in a three-phase stationary coordinate system to obtain the stator current of the permanent magnet synchronous motor in a two-phase stationary coordinate system;

[0094] As those skilled in the art know, Clarke Transformation, also known as Clarke Transformation or Clarke Equivalent Transformation, is a mathematical transformation method widely used in the fields of power electronics and motor control. It is mainly used to convert the physical quantities (such as current and voltage) of a three-phase system from a three-phase stationary coordinate system (usually expressed as ABC phases) to a two-phase stationary coordinate system (α-β coordinate system).

[0095] Step S130, performing a Park transformation on the stator current of the permanent magnet synchronous motor in a two-phase stationary coordinate system to obtain the stator current of the permanent magnet synchronous motor in a two-phase rotating coordinate system;

[0096] Those skilled in the art will know that Park Transformation, also known as Park Transformation or Parkes Transformation, is a key coordinate transformation method in the field of power electronics and motor control. It is mainly used to transform the electrical quantities (such as current and voltage) of a three-phase system from a two-phase stationary coordinate system (usually the α-β coordinate system obtained by Clarke transformation) to a rotating two-phase rotating coordinate system (dq coordinate system). The d-axis of the dq coordinate system is along the magnetic field direction (direct axis) of the synchronous motor rotor, while the q-axis is orthogonal to it (quadratic axis).

[0097] Step S140, performing harmonic extraction on the stator current of the permanent magnet synchronous motor in a two-phase rotating coordinate system by first-order bandpass filtering to obtain the fifth harmonic current component of the stator current in the two-phase rotating coordinate system.

[0098] It is worth mentioning that in this embodiment, the current component of the stator current in the three-phase stationary coordinate system is obtained by sampling the sampling resistor. However, when the feedforward compensation technology is used to compensate the harmonic voltage, since the three-phase stationary coordinate system involves the current of three phases, the harmonic analysis of the three current signals will increase the computational complexity. Therefore, it is necessary to convert the three-phase current in the three-phase stationary coordinate system to the two-phase coordinate system, reduce the harmonic analysis of one current signal, reduce the computational complexity, and improve the real-time processing capability. At the same time, since the fundamental current in the two-phase rotating coordinate system is mainly concentrated on the direct axis (the axis directly aligned with the magnetic field direction), and the harmonic current is more distributed on the quadrature axis. This separation helps to design the compensation strategy, accurately targeting the harmonic component without interfering with the fundamental current, ensuring the compensation effect while reducing unnecessary energy consumption. In addition, the rotating coordinate system can be automatically adjusted with the rotation of the motor to ensure that the compensation strategy is always consistent with the working state of the system, and can provide effective compensation even when the grid conditions change or the load fluctuates, thereby enhancing the dynamic response capability and robustness of the system.

[0099] Therefore, after obtaining the stator current of the permanent magnet synchronous motor in the three-phase stationary coordinate system through sampling resistor sampling, this implementation method converts the stator current in the three-phase stationary coordinate system into the two-phase stationary coordinate system through Clarke transformation and Park transformation in sequence for harmonic extraction.

[0100] It is not difficult to understand that the rotation frequency of the two-phase rotating coordinate system is one times the fundamental frequency.

[0101] In this implementation method, it is only necessary to set the corresponding bandpass filter parameters, and the stator current of the permanent magnet synchronous motor in the two-phase rotating coordinate system can be subjected to harmonic extraction by first-order bandpass filtering to obtain the fifth harmonic current component of the stator current in the two-phase rotating coordinate system. Compared with the method of extracting harmonic currents of different frequencies by advanced filtering in the related art, this implementation method only requires simple mathematical operations to extract the fifth harmonic current component, with lower computational complexity, faster system response speed, lower requirements on computing resources and hardware costs, and is more suitable for application in motor equipment with low control accuracy requirements, and has stronger universality.

[0102] In a feasible implementation manner, step S200 may include steps S210 to S220:

[0103] Step S210, determining a fifth harmonic voltage compensation amount of the stator current in a two-phase rotating coordinate system according to a fifth harmonic current component of the stator current in a two-phase rotating coordinate system;

[0104] Among them, the fifth harmonic current component of the stator current in the two-phase rotating coordinate system includes the first straight-axis fifth harmonic current component and the first quadrature-axis fifth harmonic current component, and the fifth harmonic voltage compensation amount of the stator current in the two-phase rotating coordinate system includes the first straight-axis fifth harmonic voltage compensation amount and the first quadrature-axis fifth harmonic voltage compensation amount.

[0105] In this embodiment, the first direct-axis fifth harmonic current component is the direct-axis component of the fifth harmonic current in the stator current in the two-phase rotating coordinate system, and the first quadrature-axis fifth harmonic current component is the quadrature-axis component of the fifth harmonic current in the stator current in the two-phase rotating coordinate system.

[0106] Correspondingly, the first straight-axis fifth harmonic voltage compensation is the direct-axis component of the fifth harmonic voltage compensation in the two-phase rotating coordinate system, which is used to compensate for the harmonic voltage corresponding to the first straight-axis fifth harmonic current component. The first quadrature-axis fifth harmonic voltage compensation is the quadrature-axis component of the fifth harmonic voltage compensation in the two-phase rotating coordinate system, which is used to compensate for the harmonic voltage corresponding to the first quadrature-axis fifth harmonic current component.

[0107] In a feasible implementation manner, the fifth harmonic current component of the stator current in the two-phase rotating coordinate system includes a first straight-axis fifth harmonic current component and a first quadrature-axis fifth harmonic current component, and the fifth harmonic voltage compensation amount of the stator current in the two-phase rotating coordinate system includes a first straight-axis fifth harmonic voltage compensation amount and a first quadrature-axis fifth harmonic voltage compensation amount, and step S210 may further include steps S211 to S213:

[0108] Step S211, obtaining the stator resistance, direct-axis inductance, quadrature-axis inductance and motor speed of the permanent magnet synchronous motor;

[0109] In this embodiment, the stator resistance refers to the resistance value of the stator winding in the permanent magnet synchronous motor, the direct-axis inductance refers to the inductance of the permanent magnet synchronous motor in the direct-axis direction, the quadrature-axis inductance refers to the inductance of the permanent magnet synchronous motor in the quadrature-axis direction, and the motor speed refers to the mechanical rotation speed of the motor shaft in the permanent magnet synchronous motor.

[0110] Step S212, substituting the stator resistance, direct-axis inductance, motor speed, and the first direct-axis fifth harmonic current component of the permanent magnet synchronous motor into a preset first direct-axis fifth harmonic voltage compensation amount calculation formula to calculate and obtain the first direct-axis fifth harmonic voltage compensation amount;

[0111] Step S213, substituting the stator resistance, quadrature-axis inductance, motor speed, and the first quadrature-axis fifth harmonic current component of the permanent magnet synchronous motor into a preset first quadrature-axis fifth harmonic voltage compensation amount calculation formula for calculation to obtain the first quadrature-axis fifth harmonic voltage compensation amount.

[0112] Among them, the calculation formula of the first direct axis fifth harmonic voltage compensation amount is:

[0113]

[0114] The calculation formula of the fifth harmonic voltage compensation amount of the first quadrature axis is:

[0115]

[0116] in, is the compensation value of the fifth harmonic voltage of the first straight axis, is the compensation value of the fifth harmonic voltage of the first quadrature axis, R is the stator resistance, is the fifth harmonic current component of the first straight axis, is the fifth harmonic current component of the first quadrature axis, Ld is the direct axis inductance, Lq is the quadrature axis inductance, is the motor speed.

[0117] This embodiment calculates the fifth harmonic voltage compensation of the stator current in the two-phase rotating coordinate system through the calculation formula of the fifth harmonic voltage compensation of the first straight axis and the calculation formula of the fifth harmonic voltage compensation of the first quadrature axis. Compared with the method of calculating the harmonic voltage compensation by complex algorithms in the related art, this embodiment reduces the complexity of real-time calculation, avoids the need to integrate advanced algorithms or complex models in the control system, makes system design and implementation more direct and simple, speeds up the system response speed, reduces the demand for high-performance processors or additional computing resources, and helps to reduce costs. At the same time, during the maintenance and debugging stage, for on-site technicians, adjusting the calculation formula is much simpler and more direct than debugging complex algorithms or setting the parameters of advanced controllers, and the engineering implementation difficulty is lower, and it is more suitable for use in motor equipment that does not require high control accuracy.

[0118] Step S220, performing an inverse Park transformation on the fifth harmonic voltage compensation amount of the stator current in the two-phase rotating coordinate system to obtain the fifth harmonic voltage compensation amount of the stator current in the two-phase stationary coordinate system.

[0119] Those skilled in the art will know that the Park Inverse Transformation, also known as the Park inverse transformation, is a mathematical transformation corresponding to the Park transformation in AC motor analysis. The Park transformation is mainly used to transform the electrical quantities (such as current and voltage) of the three-phase system from a two-phase stationary coordinate system to a rotating two-phase rotating coordinate system, while the Park inverse transformation transforms the electrical quantities of the three-phase system from a two-phase rotating coordinate system to a stationary two-phase stationary coordinate system.

[0120] It should be noted that in the voltage feedforward compensation strategy, after the harmonic voltage compensation amount in the two-phase rotating coordinate system is calculated, it is usually necessary to convert it back to the two-phase stationary coordinate system. This is because the actual voltage control and current regulation are performed in the two-phase stationary coordinate system. In order to connect with the actual control system and ensure the effective implementation of the control strategy, it is ultimately necessary to convert these calculation results (i.e., the fifth harmonic voltage compensation amount) back to a coordinate system that matches the hardware interface, that is, to convert the fifth harmonic voltage compensation amount in the two-phase rotating coordinate system to the two-phase stationary coordinate system.

[0121] This embodiment extracts the fifth harmonic current of the stator current in the two-phase rotating coordinate system through first-order bandpass filtering, which reduces the amount of calculation and improves the system response speed. It also calculates the corresponding harmonic voltage compensation through the preset first direct axis fifth harmonic voltage compensation calculation formula and the first quadrature axis fifth harmonic voltage compensation calculation formula, simplifying the calculation process. While reducing the difficulty of engineering implementation, this application ensures that the influence of the high-order harmonic current generated during the operation of the permanent magnet synchronous motor on the motor speed and torque is controlled within an acceptable range.

[0122] Embodiment 3

[0123] Please refer to Figure 3 , Figure 3 This is a schematic diagram of the extraction process of the fifth harmonic current in Example 3 of the harmonic suppression method of the present application.

[0124] In a feasible implementation manner, the permanent magnet synchronous motor includes a sampling resistor, and step S100 may include steps S150 to S170:

[0125] Step S150, acquiring the stator current of the permanent magnet synchronous motor in a three-phase stationary coordinate system by sampling with the sampling resistor;

[0126] In this embodiment, a sampling resistor is provided on the permanent magnet synchronous motor. The sampling resistor is generally provided at the input end of the stator winding, the output end of the inverter or the circuit between the stator winding and the inverter, and this embodiment does not specifically limit this.

[0127] Step S160, transforming the stator current of the permanent magnet synchronous motor in the three-phase stationary coordinate system into the five-order two-phase rotating coordinate system to obtain the stator current of the permanent magnet synchronous motor in the five-order two-phase rotating coordinate system, wherein the rotation frequency of the five-order two-phase rotating coordinate system is five times the base frequency;

[0128] It should be noted that the two-phase rotating coordinate system is a two-phase coordinate system with a rotation frequency of the base frequency (ie, fundamental frequency), and the five-order two-phase rotating coordinate system in this embodiment refers to a two-phase coordinate system with a rotation frequency of five times the base frequency.

[0129] Those skilled in the art will appreciate that, ideally, when the rotation frequency of the two-phase rotating coordinate system matches the frequency of the fifth harmonic current (i.e., the rotation frequency of the two-phase rotating coordinate system is five times the fundamental frequency), since the fifth harmonic is symmetrically distributed in space, the projections of the fifth harmonic current on the q-axis (i.e., the quadrature axis of the two-phase coordinate system) cancel each other out, resulting in the q-axis component being theoretically zero, and the d-axis (i.e., the direct axis of the two-phase coordinate system) component appearing as a "DC" component of constant amplitude (although it is actually an alternating current of a specific frequency, it appears to be constant because it rotates synchronously with the coordinate system).

[0130] Compared with transforming the stator current into a two-phase rotating coordinate system with a rotation frequency of the fundamental frequency, the present embodiment transforms the stator current into a five-order two-phase rotating coordinate system with a rotation frequency of five times the fundamental frequency, so that the fifth harmonic current appears as a DC component or an AC component that hardly rotates, greatly simplifying the analysis and processing of the fifth harmonic current. At this time, the projection of the fifth harmonic on the d-axis is significant, and the component on the q-axis is greatly weakened or disappears, so that the fifth harmonic can be directly identified and controlled, just like processing a static signal, which is crucial for accurately extracting and suppressing the fifth harmonic.

[0131] Specifically, the stator current can be transformed from the three-phase stationary coordinate system to the five-times two-phase rotating coordinate system by the following formula (1) and formula (2):

[0132]

[0133] Among them, Id is the direct-axis current component of the stator current in the five-times two-phase rotating coordinate system, Iq is the quadrature-axis current component of the stator current in the five-times two-phase rotating coordinate system, Ia is the A-phase current component of the stator current in the three-phase stationary coordinate system, Ib is the B-phase current component of the stator current in the three-phase stationary coordinate system, Ic is the C-phase current component of the stator current in the three-phase stationary coordinate system, and θ is the rotor position angle.

[0134] Those skilled in the art will appreciate that Ia, Ib and Ic are obtained through current sensing measurements, and θ can be acquired in real time through an encoder in the permanent magnet synchronous motor.

[0135] Step S170, performing harmonic extraction on the stator current of the permanent magnet synchronous motor in a fifth-order two-phase rotating coordinate system through a first-order low-pass filter to obtain a fifth harmonic current component of the stator current in the fifth-order two-phase rotating coordinate system.

[0136] After the stator current is transformed into a fifth-order two-phase rotating coordinate system with a rotation frequency five times the fundamental frequency, the projection of the fifth harmonic on the d-axis is significant, and the component on the q-axis is greatly weakened or disappears, so that the fifth harmonic can be directly identified and controlled, just like processing a static signal. Therefore, the fifth harmonic current component can be directly extracted from the stator current in the fifth-order two-phase rotating coordinate system through a first-order low-pass filter.

[0137] In a feasible implementation manner, step S200 may further include steps S230 to S240:

[0138] Step S230, determining a fifth harmonic voltage compensation amount of the stator current in a fifth two-phase rotating coordinate system according to a fifth harmonic current component of the stator current in a fifth two-phase rotating coordinate system;

[0139] Among them, the fifth harmonic current component of the stator current in the fifth two-phase rotating coordinate system includes the second direct-axis fifth harmonic current component and the second quadrature-axis fifth harmonic current component, and the fifth harmonic voltage compensation amount of the stator current in the fifth two-phase rotating coordinate system includes the second direct-axis fifth harmonic voltage compensation amount and the second quadrature-axis fifth harmonic voltage compensation amount.

[0140] In this embodiment, the second direct-axis fifth harmonic current component is the direct-axis component of the fifth harmonic current in the stator current in the fifth-order two-phase rotating coordinate system, and the second quadrature-axis fifth harmonic current component is the quadrature-axis component of the fifth harmonic current in the stator current in the fifth-order two-phase rotating coordinate system.

[0141] Correspondingly, the second direct-axis fifth harmonic voltage compensation is the direct-axis component of the fifth harmonic voltage compensation in the fifth-order two-phase rotating coordinate system, which is used to compensate for the harmonic voltage corresponding to the second direct-axis fifth harmonic current component. The second quadrature-axis fifth harmonic voltage compensation is the quadrature-axis component of the fifth harmonic voltage compensation in the fifth-order two-phase rotating coordinate system, which is used to compensate for the harmonic voltage corresponding to the second quadrature-axis fifth harmonic current component.

[0142] In a feasible implementation manner, the fifth harmonic current component of the stator current in the two-phase rotating coordinate system includes a first straight-axis fifth harmonic current component and a first quadrature-axis fifth harmonic current component, and the fifth harmonic voltage compensation amount of the stator current in the two-phase rotating coordinate system includes a first straight-axis fifth harmonic voltage compensation amount and a first quadrature-axis fifth harmonic voltage compensation amount, and step S230 may further include steps S231 to S233:

[0143] Step S231, obtaining the stator resistance, direct-axis inductance, quadrature-axis inductance and motor speed of the permanent magnet synchronous motor;

[0144] In this embodiment, the direct-axis inductance refers to the inductance of the permanent magnet synchronous motor in the direct-axis direction, the quadrature-axis inductance refers to the inductance of the permanent magnet synchronous motor in the quadrature-axis direction, and the motor speed refers to the product of the total magnetic flux of the magnetic field in the permanent magnet synchronous motor and the number of winding turns. It is an important physical quantity that characterizes the magnetic field strength and distribution in the motor.

[0145] Step S232, substituting the stator resistance, direct-axis inductance, motor speed, and the second direct-axis fifth harmonic current component of the permanent magnet synchronous motor into a preset second direct-axis fifth harmonic voltage compensation amount calculation formula to calculate and obtain the second direct-axis fifth harmonic voltage compensation amount;

[0146] Step S233, substituting the stator resistance, quadrature-axis inductance, motor speed, and the second quadrature-axis fifth harmonic current component of the permanent magnet synchronous motor into a preset second quadrature-axis fifth harmonic voltage compensation amount calculation formula for calculation to obtain the second quadrature-axis fifth harmonic voltage compensation amount.

[0147] Among them, the calculation formula of the second direct axis fifth harmonic voltage compensation amount is:

[0148]

[0149] The calculation formula of the fifth harmonic voltage compensation amount of the second quadrature axis is:

[0150]

[0151] in, is the compensation value of the second direct axis fifth harmonic voltage, is the compensation value of the fifth harmonic voltage of the second quadrature axis, R is the stator resistance, is the second direct axis fifth harmonic current component, is the second quadrature axis fifth harmonic current component, Ld is the direct axis inductance, Lq is the quadrature axis inductance, is the motor speed.

[0152] This embodiment calculates the fifth harmonic voltage compensation of the stator current in the fifth two-phase rotating coordinate system through the second direct axis fifth harmonic voltage compensation calculation formula and the second quadrature axis fifth harmonic voltage compensation calculation formula. Compared with the method of calculating the harmonic voltage compensation through complex algorithms in the related art, this embodiment reduces the complexity of real-time calculation, avoids the need to integrate advanced algorithms or complex models in the control system, makes system design and implementation more direct and simple, speeds up the system response speed, reduces the demand for high-performance processors or additional computing resources, and helps to reduce costs. At the same time, during the maintenance and debugging stage, for on-site technicians, adjusting the calculation formula is much simpler and more direct than debugging complex algorithms or setting the parameters of advanced controllers, and the engineering implementation difficulty is lower, and it is more suitable for use in motor equipment that does not require high control accuracy.

[0153] Step S240, transforming the fifth harmonic voltage compensation amount of the stator current in the fifth two-phase rotating coordinate system into the two-phase stationary coordinate system to obtain the fifth harmonic voltage compensation amount of the stator current in the two-phase stationary coordinate system.

[0154] In this embodiment, after the fifth harmonic voltage compensation amount of the stator current in the fifth two-phase rotating coordinate system is calculated, the fifth harmonic voltage compensation amount can be transformed from the fifth two-phase rotating coordinate system to the two-phase stationary coordinate system by the following formula (III) and formula (IV):

[0155]

[0156] in, is the α-axis component of the fifth harmonic voltage compensation of the stator current in the two-phase stationary coordinate system, is the β-axis component of the fifth harmonic voltage compensation of the stator current in the two-phase stationary coordinate system, is the compensation value of the second direct axis fifth harmonic voltage, is the compensation amount of the fifth harmonic voltage of the second quadrature axis, and θ is the rotor position angle.

[0157] This embodiment extracts the fifth harmonic current from the stator current in the fifth two-phase rotating coordinate system through a first-order low-pass filter, which reduces the amount of calculation and improves the system response speed. It also calculates the corresponding harmonic voltage compensation through the preset second direct-axis fifth harmonic voltage compensation calculation formula and the second quadrature-axis fifth harmonic voltage compensation calculation formula, simplifying the calculation process. While reducing the difficulty of engineering implementation, this application ensures that the influence of the high-order harmonic current generated during the operation of the permanent magnet synchronous motor on the motor speed and torque is controlled within an acceptable range.

[0158] In addition, please refer to Figure 4 , Figure 4 Schematic diagram of the module structure of the harmonic suppression device according to an embodiment of the present application.

[0159] The embodiment of the present application further provides a harmonic suppression device, which is applied to a permanent magnet synchronous motor, comprising:

[0160] A harmonic current extraction module 10 is used to extract harmonics from the stator current of the permanent magnet synchronous motor to obtain the fifth harmonic current component of the stator current;

[0161] A harmonic compensation calculation module 20, used to determine the fifth harmonic voltage compensation amount of the stator current according to the fifth harmonic current component of the stator current;

[0162] The voltage feedforward compensation module 30 is used to perform voltage feedforward compensation on the permanent magnet synchronous motor based on the fifth harmonic voltage compensation amount of the stator current.

[0163] In one embodiment, the permanent magnet synchronous motor includes a sampling resistor;

[0164] The harmonic current extraction module 10 is also used for:

[0165] Acquiring the stator current of the permanent magnet synchronous motor in a three-phase stationary coordinate system by sampling the sampling resistor;

[0166] Performing Clarke transformation on the stator current of the permanent magnet synchronous motor in a three-phase stationary coordinate system to obtain the stator current of the permanent magnet synchronous motor in a two-phase stationary coordinate system;

[0167] Performing a Park transformation on the stator current of the permanent magnet synchronous motor in a two-phase stationary coordinate system to obtain the stator current of the permanent magnet synchronous motor in a two-phase rotating coordinate system;

[0168] Harmonics of the stator current of the permanent magnet synchronous motor in a two-phase rotating coordinate system are extracted by first-order bandpass filtering to obtain the fifth harmonic current component of the stator current in the two-phase rotating coordinate system.

[0169] In one embodiment, the permanent magnet synchronous motor includes a sampling resistor;

[0170] The harmonic current extraction module 10 is also used for:

[0171] Acquiring the stator current of the permanent magnet synchronous motor in a three-phase stationary coordinate system by sampling the sampling resistor;

[0172] The stator current of the permanent magnet synchronous motor in the three-phase stationary coordinate system is transformed into the five-order two-phase rotating coordinate system to obtain the stator current of the permanent magnet synchronous motor in the five-order two-phase rotating coordinate system, wherein the rotation frequency of the five-order two-phase rotating coordinate system is five times the base frequency;

[0173] Harmonics of the stator current of the permanent magnet synchronous motor in a fifth-order two-phase rotating coordinate system are extracted by first-order low-pass filtering to obtain a fifth harmonic current component of the stator current in the fifth-order two-phase rotating coordinate system.

[0174] In one embodiment, the harmonic compensation calculation module 20 is further used for:

[0175] Determining a fifth harmonic voltage compensation amount of the stator current in the two-phase rotating coordinate system according to the fifth harmonic current component of the stator current in the two-phase rotating coordinate system;

[0176] The fifth harmonic voltage compensation amount of the stator current in the two-phase rotating coordinate system is subjected to an inverse Park transformation to obtain the fifth harmonic voltage compensation amount of the stator current in the two-phase stationary coordinate system.

[0177] In one embodiment, the fifth harmonic current component of the stator current in the two-phase rotating coordinate system includes a first straight-axis fifth harmonic current component and a first quadrature-axis fifth harmonic current component, and the fifth harmonic voltage compensation amount of the stator current in the two-phase rotating coordinate system includes a first straight-axis fifth harmonic voltage compensation amount and a first quadrature-axis fifth harmonic voltage compensation amount;

[0178] The voltage feedforward compensation module 20 is also used for:

[0179] Obtaining the stator resistance, direct-axis inductance, quadrature-axis inductance and motor speed of the permanent magnet synchronous motor;

[0180] Substituting the stator resistance, direct-axis inductance, motor speed, and the first direct-axis fifth harmonic current component of the permanent magnet synchronous motor into a preset first direct-axis fifth harmonic voltage compensation amount calculation formula for calculation, to obtain the first direct-axis fifth harmonic voltage compensation amount;

[0181] Substituting the stator resistance, quadrature-axis inductance, motor speed, and the first quadrature-axis fifth harmonic current component of the permanent magnet synchronous motor into a preset first quadrature-axis fifth harmonic voltage compensation amount calculation formula for calculation, to obtain the first quadrature-axis fifth harmonic voltage compensation amount;

[0182] Among them, the calculation formula of the first direct axis fifth harmonic voltage compensation amount is:

[0183]

[0184] The calculation formula of the fifth harmonic voltage compensation amount of the first quadrature axis is:

[0185]

[0186] in, is the compensation value of the fifth harmonic voltage of the first straight axis, is the compensation value of the fifth harmonic voltage of the first quadrature axis, R is the stator resistance, is the fifth harmonic current component of the first straight axis, is the fifth harmonic current component of the first quadrature axis, Ld is the direct axis inductance, Lq is the quadrature axis inductance, is the motor speed.

[0187] In one embodiment, the harmonic compensation calculation module 20 is further used for:

[0188] Determining a fifth harmonic voltage compensation amount of the stator current in a fifth two-phase rotating coordinate system according to a fifth harmonic current component of the stator current in a fifth two-phase rotating coordinate system;

[0189] The fifth harmonic voltage compensation amount of the stator current in the fifth two-phase rotating coordinate system is transformed into the two-phase stationary coordinate system to obtain the fifth harmonic voltage compensation amount of the stator current in the two-phase stationary coordinate system.

[0190] In one embodiment, the fifth harmonic current component of the stator current in the fifth two-phase rotating coordinate system includes a second direct-axis fifth harmonic current component and a second quadrature-axis fifth harmonic current component, and the fifth harmonic voltage compensation amount of the stator current in the fifth two-phase rotating coordinate system includes a second direct-axis fifth harmonic voltage compensation amount and a second quadrature-axis fifth harmonic voltage compensation amount;

[0191] The harmonic compensation calculation module 20 is also used for:

[0192] Obtaining the stator resistance, direct-axis inductance, quadrature-axis inductance and motor speed of the permanent magnet synchronous motor;

[0193] Substituting the stator resistance, direct-axis inductance, motor speed, and the second direct-axis fifth harmonic current component of the permanent magnet synchronous motor into a preset second direct-axis fifth harmonic voltage compensation amount calculation formula for calculation, to obtain the second direct-axis fifth harmonic voltage compensation amount;

[0194] Substituting the stator resistance, quadrature-axis inductance, motor speed, and the second quadrature-axis fifth harmonic current component of the permanent magnet synchronous motor into a preset second quadrature-axis fifth harmonic voltage compensation amount calculation formula for calculation, to obtain the second quadrature-axis fifth harmonic voltage compensation amount;

[0195] Among them, the calculation formula of the second direct axis fifth harmonic voltage compensation amount is:

[0196]

[0197] The calculation formula of the fifth harmonic voltage compensation amount of the second quadrature axis is:

[0198]

[0199] in, is the compensation value of the second direct axis fifth harmonic voltage, is the compensation value of the fifth harmonic voltage of the second quadrature axis, R is the stator resistance, is the second direct axis fifth harmonic current component, is the second quadrature axis fifth harmonic current component, Ld is the direct axis inductance, Lq is the quadrature axis inductance, is the motor speed.

[0200] The harmonic suppression device provided in the embodiment of the present application adopts the harmonic suppression method in the above embodiment, which can reduce the impact of high-order harmonic currents on the motor while reducing the difficulty of engineering implementation. Compared with the prior art, the beneficial effects of the harmonic suppression device provided in the embodiment of the present application are the same as the beneficial effects of the harmonic suppression method provided in the above embodiment, and other technical features in the harmonic suppression device are the same as the features disclosed in the above embodiment method, which will not be repeated here.

[0201] In addition, please refer to Figure 5 , Figure 5 Schematic diagram of the device structure of the hardware operating environment involved in the harmonic suppression method in the embodiment of the present application.

[0202] The present application provides a permanent magnet synchronous motor, comprising: at least one processor; and a memory connected to the at least one processor in communication; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the harmonic suppression method in the above-mentioned embodiment one.

[0203] Reference below Figure 5 , which shows a structural schematic diagram of a permanent magnet synchronous motor suitable for implementing an embodiment of the present application. Figure 5 The permanent magnet synchronous motor shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0204] like Figure 5As shown, the permanent magnet synchronous motor may include a processing device 1001 (e.g., a central processing unit, a graphics processor, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM: Read Only Memory) 1002 or a program loaded from a storage device 1003 to a random access memory (RAM: Random Access Memory) 1004. In RAM1004, various programs and data required for the operation of the permanent magnet synchronous motor are also stored. The processing device 1001, ROM1002, and RAM1004 are connected to each other through a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Generally, the following systems can be connected to the I / O interface 1006: an input device 1007 including, for example, a touch screen, a touch pad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc.; an output device 1008 including, for example, a liquid crystal display (LCD: Liquid Crystal Display), a speaker, a vibrator, etc.; a storage device 1003 including, for example, a magnetic tape, a hard disk, etc.; and a communication device 1009. The communication device 1009 can allow the permanent magnet synchronous motor to communicate with other devices wirelessly or by wire to exchange data. Although the figure shows a permanent magnet synchronous motor with various systems, it should be understood that it is not required to implement or have all the systems shown. More or fewer systems can be implemented or have alternatively.

[0205] In particular, according to the embodiments disclosed in the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments disclosed in the present application include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication device, or installed from a storage device 1003, or installed from a ROM 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the method of the embodiment disclosed in the present application are executed.

[0206] The permanent magnet synchronous motor provided by the present application adopts the harmonic suppression method in the above embodiment, which can reduce the impact of high-order harmonic currents on the motor while reducing the difficulty of engineering implementation. Compared with the prior art, the beneficial effects of the permanent magnet synchronous motor provided by the present application are the same as the beneficial effects of the harmonic suppression method provided by the above embodiment, and the other technical features in the permanent magnet synchronous motor are the same as the features disclosed in the method of the previous embodiment, which will not be repeated here.

[0207] It should be understood that the various parts disclosed in this application can be implemented by hardware, software, firmware or a combination thereof. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0208] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0209] The present application provides a computer-readable storage medium having computer-readable program instructions (ie, computer programs) stored thereon, and the computer-readable program instructions are used to execute the harmonic suppression method in the above-mentioned embodiment.

[0210] The computer-readable storage medium provided in the present application may be, for example, a USB flash drive, but is not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, systems or devices, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, system or device. The program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination of the above.

[0211] The computer-readable storage medium may be included in the permanent magnet synchronous motor; or may exist independently without being assembled into the permanent magnet synchronous motor.

[0212] The computer-readable storage medium carries one or more programs. When the one or more programs are executed by the controller of the permanent magnet synchronous motor, the controller of the permanent magnet synchronous motor: performs harmonic extraction on the stator current of the permanent magnet synchronous motor to obtain the fifth harmonic current component of the stator current; determines the fifth harmonic voltage compensation amount of the stator current according to the fifth harmonic current component of the stator current; and performs voltage feed-forward compensation on the permanent magnet synchronous motor based on the fifth harmonic voltage compensation amount of the stator current.

[0213] Computer program code for performing the operations of the present application may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0214] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0215] The modules involved in the embodiments described in this application may be implemented by software or hardware, wherein the name of the module does not constitute a limitation on the unit itself in some cases.

[0216] The readable storage medium provided in the present application is a computer-readable storage medium, which stores computer-readable program instructions (i.e., computer programs) for executing the above-mentioned harmonic suppression method, and can reduce the impact of high-order harmonic currents on the motor while reducing the difficulty of engineering implementation. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in the present application are the same as the beneficial effects of the harmonic suppression method provided in the above-mentioned embodiment, and will not be repeated here.

[0217] The above descriptions are only some embodiments of the present application, and are not intended to limit the patent scope of the present application. All equivalent structural changes made using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect applications in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A harmonic suppression method, characterized in that: The harmonic suppression method is applied to a permanent magnet synchronous motor, and the method comprises: Performing harmonic extraction on the stator current of the permanent magnet synchronous motor to obtain the fifth harmonic current component of the stator current; Determining a fifth harmonic voltage compensation amount of the stator current according to a fifth harmonic current component of the stator current; Based on the fifth harmonic voltage compensation amount of the stator current, voltage feedforward compensation is performed on the permanent magnet synchronous motor.

2. The harmonic suppression method according to claim 1, characterized in that: The permanent magnet synchronous motor includes a sampling resistor, and the step of performing harmonic extraction on the stator current of the permanent magnet synchronous motor to obtain the fifth harmonic current component of the stator current includes: Acquiring the stator current of the permanent magnet synchronous motor in a three-phase stationary coordinate system by sampling the sampling resistor; Performing Clarke transformation on the stator current of the permanent magnet synchronous motor in a three-phase stationary coordinate system to obtain the stator current of the permanent magnet synchronous motor in a two-phase stationary coordinate system; Performing a Park transformation on the stator current of the permanent magnet synchronous motor in a two-phase stationary coordinate system to obtain the stator current of the permanent magnet synchronous motor in a two-phase rotating coordinate system; Harmonics of the stator current of the permanent magnet synchronous motor in a two-phase rotating coordinate system are extracted by first-order bandpass filtering to obtain the fifth harmonic current component of the stator current in the two-phase rotating coordinate system.

3. The harmonic suppression method according to claim 2, characterized in that: The step of determining the fifth harmonic voltage compensation amount of the stator current according to the fifth harmonic current component of the stator current comprises: Determining a fifth harmonic voltage compensation amount of the stator current in the two-phase rotating coordinate system according to the fifth harmonic current component of the stator current in the two-phase rotating coordinate system; The fifth harmonic voltage compensation amount of the stator current in the two-phase rotating coordinate system is subjected to an inverse Park transformation to obtain the fifth harmonic voltage compensation amount of the stator current in the two-phase stationary coordinate system.

4. The harmonic suppression method according to claim 3, characterized in that: The fifth harmonic current component of the stator current in the two-phase rotating coordinate system includes a first straight-axis fifth harmonic current component and a first quadrature-axis fifth harmonic current component, and the fifth harmonic voltage compensation amount of the stator current in the two-phase rotating coordinate system includes a first straight-axis fifth harmonic voltage compensation amount and a first quadrature-axis fifth harmonic voltage compensation amount; The step of determining the fifth harmonic voltage compensation amount of the stator current in the two-phase rotating coordinate system according to the fifth harmonic current component of the stator current in the two-phase rotating coordinate system comprises: Obtaining the stator resistance, direct-axis inductance, quadrature-axis inductance and motor speed of the permanent magnet synchronous motor; Substituting the stator resistance, direct-axis inductance, motor speed, and the first direct-axis fifth harmonic current component of the permanent magnet synchronous motor into a preset first direct-axis fifth harmonic voltage compensation amount calculation formula for calculation, to obtain the first direct-axis fifth harmonic voltage compensation amount; Substituting the stator resistance, quadrature-axis inductance, motor speed, and the first quadrature-axis fifth harmonic current component of the permanent magnet synchronous motor into a preset first quadrature-axis fifth harmonic voltage compensation amount calculation formula for calculation, to obtain the first quadrature-axis fifth harmonic voltage compensation amount; Among them, the calculation formula of the first direct axis fifth harmonic voltage compensation amount is: The calculation formula of the fifth harmonic voltage compensation amount of the first quadrature axis is: in, is the compensation value of the fifth harmonic voltage of the first straight axis, is the compensation value of the fifth harmonic voltage of the first quadrature axis, R is the stator resistance, is the fifth harmonic current component of the first straight axis, is the fifth harmonic current component of the first quadrature axis, Ld is the direct axis inductance, Lq is the quadrature axis inductance, is the motor speed.

5. The harmonic suppression method according to claim 1, characterized in that: The permanent magnet synchronous motor includes a sampling resistor, and the step of performing harmonic extraction on the stator current of the permanent magnet synchronous motor to obtain the fifth harmonic current component of the stator current includes: Acquiring the stator current of the permanent magnet synchronous motor in a three-phase stationary coordinate system by sampling the sampling resistor; The stator current of the permanent magnet synchronous motor in the three-phase stationary coordinate system is transformed into the five-order two-phase rotating coordinate system to obtain the stator current of the permanent magnet synchronous motor in the five-order two-phase rotating coordinate system, wherein the rotation frequency of the five-order two-phase rotating coordinate system is five times the base frequency; Harmonics of the stator current of the permanent magnet synchronous motor in a fifth-order two-phase rotating coordinate system are extracted by first-order low-pass filtering to obtain a fifth harmonic current component of the stator current in the fifth-order two-phase rotating coordinate system.

6. The harmonic suppression method according to claim 5, characterized in that: Determining the fifth harmonic voltage compensation amount of the stator current according to the fifth harmonic current component of the stator current; Determining a fifth harmonic voltage compensation amount of the stator current in a fifth two-phase rotating coordinate system according to a fifth harmonic current component of the stator current in a fifth two-phase rotating coordinate system; The fifth harmonic voltage compensation amount of the stator current in the fifth two-phase rotating coordinate system is transformed into the two-phase stationary coordinate system to obtain the fifth harmonic voltage compensation amount of the stator current in the two-phase stationary coordinate system.

7. The harmonic suppression method according to claim 6, characterized in that: The fifth harmonic current component of the stator current in the fifth two-phase rotating coordinate system includes a second direct-axis fifth harmonic current component and a second quadrature-axis fifth harmonic current component, and the fifth harmonic voltage compensation amount of the stator current in the fifth two-phase rotating coordinate system includes a second direct-axis fifth harmonic voltage compensation amount and a second quadrature-axis fifth harmonic voltage compensation amount; The step of determining the fifth harmonic voltage compensation amount of the stator current in the fifth two-phase rotating coordinate system according to the fifth harmonic current component of the stator current in the fifth two-phase rotating coordinate system comprises: Obtaining the stator resistance, direct-axis inductance, quadrature-axis inductance and motor speed of the permanent magnet synchronous motor; Substituting the stator resistance, direct-axis inductance, motor speed, and the second direct-axis fifth harmonic current component of the permanent magnet synchronous motor into a preset second direct-axis fifth harmonic voltage compensation amount calculation formula for calculation, to obtain the second direct-axis fifth harmonic voltage compensation amount; Substituting the stator resistance, quadrature-axis inductance, motor speed, and the second quadrature-axis fifth harmonic current component of the permanent magnet synchronous motor into a preset second quadrature-axis fifth harmonic voltage compensation amount calculation formula for calculation, to obtain the second quadrature-axis fifth harmonic voltage compensation amount; Among them, the calculation formula of the second direct axis fifth harmonic voltage compensation amount is: The calculation formula of the fifth harmonic voltage compensation amount of the second quadrature axis is: in, is the compensation value of the second direct axis fifth harmonic voltage, is the compensation value of the fifth harmonic voltage of the second quadrature axis, R is the stator resistance, is the second direct axis fifth harmonic current component, is the second quadrature axis fifth harmonic current component, Ld is the direct axis inductance, Lq is the quadrature axis inductance, is the motor speed.

8. A harmonic suppression device, characterized in that: The harmonic suppression device is applied to a permanent magnet synchronous motor, and the device comprises: A harmonic current extraction module, used for performing harmonic extraction on the stator current of the permanent magnet synchronous motor to obtain the fifth harmonic current component of the stator current; A harmonic compensation calculation module, used to determine the fifth harmonic voltage compensation amount of the stator current according to the fifth harmonic current component of the stator current; A voltage feedforward compensation module is used to perform voltage feedforward compensation on the permanent magnet synchronous motor based on the fifth harmonic voltage compensation amount of the stator current.

9. A permanent magnet synchronous motor, characterized in that: The permanent magnet synchronous motor comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the harmonic suppression method according to any one of claims 1 to 7.

10. A storage medium, characterized in that: The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, the steps of the harmonic suppression method according to any one of claims 1 to 7 are implemented.

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