Method and system for reducing electromagnetic vibration and noise of permanent magnet synchronous motor

Abstract

The application provides a method and system for reducing electromagnetic vibration and noise of a permanent magnet synchronous motor. The method comprises injecting a pulse high-frequency voltage signal under position sensorless control, the injected pulse high-frequency voltage signal interacts with a fundamental frequency signal to generate sideband current harmonics near the voltage frequency in a low frequency band and near a PWM switching frequency; only considering the magnetic flux density component with a spatial order p generated by the fundamental wave of the stator current, the magnetic flux density component interacts with the radial air gap magnetic flux density generated by the fundamental wave of the permanent magnet to generate new air gap magnetic flux density and electromagnetic force wave order and frequency near the injected voltage frequency; considering the air gap magnetic flux density generated by the sideband current harmonics and the air gap magnetic flux density generated by the fundamental wave of the permanent magnet, electromagnetic force waves generated by the sideband current harmonics are obtained; by comparing parameters under different operating conditions of the permanent magnet synchronous motor, a suitable frequency of the injected pulse high-frequency voltage signal is selected, so that the frequency of the generated electromagnetic force waves is far away from the inherent modal frequency of the permanent magnet synchronous motor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of permanent magnet synchronous motor, and particularly relates to a method and system for reducing electromagnetic vibration and noise of permanent magnet synchronous motor. BACKGROUND

[0002] The statements in this section merely provide background information related to the present application and do not necessarily constitute the prior art.

[0003] Permanent magnet synchronous motor is widely used in electric vehicles, aerospace, new energy power generation and other important equipment fields due to its small size, high reliability, high efficiency, small loss, high power density and simple and compact structure. However, the pursuit of high power density, light weight and small size and wide speed range makes the motor magnetic field harmonic rich and high in amplitude, which easily causes large electromagnetic vibration and noise and even resonance. The high performance driving of the motor is closely related to the control strategy of the motor. In order to realize high performance control, especially vector control, high precision control of the motor inner loop current loop and outer loop speed loop is needed, which needs to rely on position sensors such as incremental digital encoder and rotary transformer to obtain accurate rotor position information. However, the use of these high-precision and high-response mechanical position sensors will increase the system cost, increase the overall volume, reduce the anti-interference ability, reduce the precision in extreme working environment and reduce the environmental adaptability, which seriously affects the reliability of the system and limits the popularization and application of the permanent magnet synchronous motor. Therefore, sensorless control has become an important topic in the field of permanent magnet motor.

[0004] According to the different operating speed ranges of the motor, the selection of the sensorless control strategy is also different. When the permanent magnet synchronous motor runs at zero or low speed, high frequency signal injection method is mainly used, which demodulates the position information in the response current by using the salient pole characteristics of the motor, mainly including rotating high frequency signal injection method, pulsating high frequency signal injection method and high frequency square wave signal injection method. However, the injection of high frequency signal at zero or low speed of the motor will produce large vibration and noise, which greatly limits the development of sensorless control strategy.

[0005] At present, the research on high frequency injection method sensorless control of permanent magnet synchronous motor mainly focuses on the improvement of observation accuracy and the power spectral density analysis of current waveform, and the influence of electromagnetic vibration and noise of permanent magnet synchronous motor is not analyzed and researched in detail, and only the vibration and noise caused by the fundamental wave and low frequency current harmonics are analyzed. As for the sideband current harmonics near the switching frequency, they are simplified and omitted because their amplitudes are much smaller than the fundamental wave current. From this point of view, considering the resonance with the inherent modal frequency of the motor, the electromagnetic vibration and noise caused by the electromagnetic force wave introduced by the sideband current harmonics with small amplitude when the time frequency is close to the inherent frequency cannot be ignored. SUMMARY

[0006] In order to solve the technical problems in the background art, the application provides a method and system for reducing electromagnetic vibration and noise of a permanent magnet synchronous motor, which utilizes a pulse-vibration high-frequency voltage excitation in a direct-axis to demodulate a high-frequency response current to obtain rotor position information, thereby realizing zero-low-speed position sensorless control.

[0007] In order to achieve the above-mentioned purpose, the application adopts the following technical scheme:

[0008] The first aspect of the application provides a method for reducing electromagnetic vibration and noise of a permanent magnet synchronous motor.

[0009] The method for reducing electromagnetic vibration and noise of a permanent magnet synchronous motor comprises the following steps:

[0010] A pulse-vibration high-frequency voltage signal is injected under position sensorless control, the injected pulse-vibration high-frequency voltage signal interacts with a fundamental frequency signal, and sideband current harmonics are generated in a low frequency band near the injection voltage frequency and near the PWM switching frequency.

[0011] Only the magnetic flux density component with a spatial order of p generated by the stator current fundamental wave is considered, which interacts with the radial air gap magnetic flux density generated by the permanent magnet fundamental wave to generate new air gap magnetic flux density and electromagnetic force wave order and frequency near the injection voltage frequency.

[0012] The air gap magnetic flux density generated by the sideband current harmonics interacts with the air gap magnetic flux density generated by the permanent magnet fundamental wave to obtain the electromagnetic force wave generated by the sideband current harmonics.

[0013] By comparing parameters under different operating conditions of the permanent magnet synchronous motor, a suitable frequency of the injected pulse-vibration high-frequency voltage signal is selected, so that the frequency of the generated electromagnetic force wave is far away from the inherent modal frequency of the permanent magnet synchronous motor, thereby reducing the electromagnetic vibration and noise of the permanent magnet synchronous motor.

[0014] Further, the position sensorless control is that a pulse-vibration high-frequency voltage signal is injected in an estimated two-phase rotating coordinate system direct-axis, the voltage drop of the stator resistance and the permanent magnet flux linkage as the fundamental signal are ignored, the high-frequency current induced on the cross-axis is demodulated to obtain the rotor position information.

[0015] Further, the process of demodulating the quadrature-axis high-frequency current induced by the quadrature-axis includes: multiplying the quadrature-axis high-frequency current with a sinusoidal signal, extracting a position deviation signal through a low-pass filter, and finally making the position deviation signal 0 through a proportional-integral regulator to obtain the rotor position information.

[0016] Further, the process of considering the interaction between the air-gap flux density generated by the sideband current harmonic and the air-gap flux density generated by the permanent magnet fundamental wave to obtain the electromagnetic force wave generated by the sideband current harmonic includes: in the low frequency band, only considering the electromagnetic force wave generated by the interaction between the radial air-gap flux density generated by the permanent magnet fundamental wave and the magnetic flux density component with a spatial order of p generated by the stator current fundamental wave; in the high frequency band, only considering the electromagnetic force wave generated by the interaction between the radial air-gap flux density generated by the permanent magnet fundamental wave and the magnetic flux density component with a spatial order of p generated by the sideband current harmonic.

[0017] Further, the radial air-gap flux density generated by the sideband current harmonic is represented by the following formula:

[0018]

[0019] cos(((κ±2m)p±lZ)θ-(ω ch ±2mω1)t-θ v )

[0020]

[0021] wherein f c is the magnetic motive force generated by the sideband current harmonic, λ is the air-gap permeance, p is the number of pole pairs, Z is the number of stator slots, ω1 is the fundamental wave frequency, ω ch is the frequency of the sideband current harmonic, κ is the spatial order harmonic number of the magnetic motive force generated by the sideband current harmonic, B ckml is the air-gap flux density amplitude generated by the sideband current harmonic, F ck is the magnetic motive force amplitude generated by the sideband current harmonic, Λ r2m is the 2m (m=1, 2, 3,...) permeance harmonic amplitude generated by the rotor salient pole structure, Λ sl is the l (l=1, 2, 3,...) permeance harmonic amplitude generated by the stator slotting.

[0022] Further, the process of considering the interaction between the air-gap flux density generated by the sideband current harmonic and the air-gap flux density generated by the permanent magnet fundamental wave to obtain the electromagnetic force wave generated by the sideband current harmonic is represented by the following formula:

[0023]

[0024] wherein B c0 and B r0The air gap magnetic flux amplitude generated by the sideband current harmonics and the air gap magnetic flux amplitude generated by the permanent magnet fundamental wave, respectively, and mu0 is the magnetic permeability of vacuum.

[0025] Further, the process of obtaining the natural modal frequency of the permanent magnet synchronous motor comprises: by hammering method, a plurality of test points on the four surfaces of the permanent magnet synchronous motor are radially knocked by a knocking force hammer one by one, the knocking force of the knocking force hammer causes a force response in the permanent magnet synchronous motor to induce vibration, and signals are transmitted to a data acquisition instrument by an acceleration sensor for analysis and processing, so that the natural modal frequency of the permanent magnet synchronous motor of different orders is obtained.

[0026] The second aspect of the present application provides a system for reducing electromagnetic vibration and noise of a permanent magnet synchronous motor.

[0027] The system for reducing electromagnetic vibration and noise of a permanent magnet synchronous motor comprises:

[0028] The sideband current harmonic generation module is configured to inject a pulsating high-frequency voltage signal under sensorless control, and the injected pulsating high-frequency voltage signal interacts with a fundamental wave signal to generate sideband current harmonics near the voltage frequency in the low frequency band and near the PWM switching frequency.

[0029] The interaction module is configured to only consider the magnetic flux component with a spatial order p generated by the stator current fundamental wave, and interact with the radial air gap magnetic flux generated by the permanent magnet fundamental wave to generate new air gap magnetic flux and electromagnetic force wave orders and frequencies near the injected voltage frequency.

[0030] The electromagnetic force wave generation module is configured to consider the interaction between the air gap magnetic flux generated by the sideband current harmonics and the air gap magnetic flux generated by the permanent magnet fundamental wave to obtain the electromagnetic force wave generated by the sideband current harmonics.

[0031] The control module is configured to compare parameters under different operating conditions of the permanent magnet synchronous motor, select a suitable frequency of the injected pulsating high-frequency voltage signal, and make the frequency of the generated electromagnetic force wave far away from the natural modal frequency of the permanent magnet synchronous motor, so as to reduce the electromagnetic vibration and noise of the permanent magnet synchronous motor.

[0032] The third aspect of the present application provides a computer readable storage medium.

[0033] A computer readable storage medium has a computer program stored thereon, and the program is executed by a processor to implement the steps in the method for reducing electromagnetic vibration and noise of a permanent magnet synchronous motor according to the first aspect.

[0034] The fourth aspect of the present application provides a computer device.

[0035] The computer device comprises a memory, a processor, and a computer program stored on the memory and executable on the processor, and the processor implements the steps in the method for reducing electromagnetic vibration and noise of a permanent magnet synchronous motor according to the first aspect.

[0036] Compared with the prior art, the present application has the following beneficial effects:

[0037] The present application considers the electromagnetic vibration and noise caused by the sideband current harmonics near the switching frequency introducing electromagnetic force waves close to the natural frequency in time frequency, and further reduces the electromagnetic vibration and noise.

[0038] The present application analyzes the harmonic components of the voltage and current generated by the pulse high-frequency voltage signal injection position sensorless control strategy, analyzes and deduces the spatial order and time frequency distribution of the sideband current harmonic components generated under the space vector pulse width modulation driving mode, and obtains the newly generated electromagnetic force wave components of the pulse high-frequency voltage signal injection permanent magnet synchronous motor without position sensor control.

[0039] The present application can change the time frequency distribution of the newly generated electromagnetic force wave by changing the frequency of the injected signal and the PWM switching frequency, and at the same time considers the running speed of the motor, so that the newly generated electromagnetic force wave of a specific order is far away from the natural modal frequency of the motor to avoid resonance, which can effectively reduce the electromagnetic vibration and noise. BRIEF DESCRIPTION OF DRAWINGS

[0040] The drawings accompanying the specification of the present application serve to provide a further understanding of the present application, and the illustrative embodiments of the present application and their descriptions serve to explain the present application, and do not constitute an improper limitation on the present application.

[0041] Figure 1 is a frame diagram of the pulse high-frequency voltage injection position control system shown in the present application;

[0042] Figure 2 is a current spectrum diagram in the low frequency band after the high-frequency pulse signal injection shown in the present application;

[0043] Figure 3 is a first carrier sideband current spectrum diagram after the high-frequency pulse signal injection shown in the present application;

[0044] Figure 4 is a low-frequency vibration measurement diagram after the high-frequency pulse signal injection shown in the present application;

[0045] Figure 5 is a first carrier sideband vibration measurement diagram after the high-frequency pulse signal injection shown in the present application;

[0046] Figure 6 is a flowchart of the method for reducing electromagnetic vibration and noise of a permanent magnet synchronous motor according to the present application. DETAILED DESCRIPTION

[0047] The present application is further described in connection with the following examples and drawings.

[0048] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0049] It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting, as the scope of the exemplary embodiments of this application will be limited to the claims. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0050] It should be noted that the flow diagrams and block diagrams in the drawings are representative of the architectural, functional, and operational aspects of possible implementations of the methods and systems according to various embodiments of the present disclosure. It should be noted that each block in the flow diagrams and / or block diagrams can represent a module, a segment, or a portion of code, which includes one or more executable instructions for implementing the specified logical function(s). It should also be noted that in some alternative implementations, the functions noted in the box can occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently or the blocks can sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each of the boxes and combinations of boxes in the flow diagrams and / or block diagrams can be implemented with special purpose hardware-based systems which perform the specified functions or operations, or combinations of special purpose hardware and

[0051] Embodiment One

[0052] As Figure 6As shown, the embodiment provides a method for reducing electromagnetic vibration and noise of a permanent magnet synchronous motor. The method is applied to a server for illustration. It should be understood that the method can also be applied to a terminal and can also be applied to a system including a terminal and a server and realized through interaction of the terminal and the server. The server can be a standalone physical server, a server cluster composed of multiple physical servers or a distributed system, or a cloud server providing cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network servers, cloud communication, middleware services, domain name services, security services CDN, and basic cloud computing services such as big data and artificial intelligence platforms. The terminal can be a smartphone, a tablet computer, a notebook computer, a desktop computer, a smart speaker, a smart watch, and the like, but is not limited thereto. The terminal and the server can be directly or indirectly connected through wired or wireless communication, which is not limited in the present application. In the embodiment, the method includes the following steps:

[0053] A pulse-vibration high-frequency voltage signal is injected under position sensorless control, and the injected pulse-vibration high-frequency voltage signal interacts with a fundamental frequency signal to generate sideband current harmonics near the voltage frequency and near the PWM switching frequency in the low frequency band; wherein the position sensorless control strategy is to inject a pulse-vibration high-frequency voltage signal in the estimated two-phase rotating coordinate system direct axis, ignore the voltage drop of the stator resistance and the permanent magnet flux linkage as the fundamental signal, demodulate the high-frequency current induced on the cross axis to obtain the rotor position information.

[0054] Only the magnetic flux component with a spatial order of p generated by the fundamental wave of the stator current interacts with the radial air gap magnetic flux generated by the fundamental wave of the permanent magnet to generate new air gap magnetic flux and electromagnetic force wave orders and frequencies near the injected voltage frequency;

[0055] The air gap magnetic flux generated by the sideband current harmonics interacts with the air gap magnetic flux generated by the fundamental wave of the permanent magnet to obtain the electromagnetic force wave generated by the sideband current harmonics;

[0056] By comparing the parameters under different operating conditions of the permanent magnet synchronous motor, a suitable frequency of the injected pulse-vibration high-frequency voltage signal is selected so that the frequency of the electromagnetic force wave generated thereby is far away from the inherent modal frequency of the permanent magnet synchronous motor, thereby reducing the electromagnetic vibration and noise of the permanent magnet synchronous motor.

[0057] The application is directed to the influence of motor electromagnetic vibration and noise in the process, the injected voltage signal interacts with the fundamental voltage, new harmonic components are generated near the injection voltage frequency and the PWM switching frequency, and the new high-frequency electromagnetic force wave components generated by the pulse high-frequency voltage injection are obtained. Considering the different operating speed conditions of the motor, the frequency or PWM switching frequency of the injected signal is changed, so that the newly added electromagnetic force wave frequency is far away from the inherent modal frequency of the motor, which can effectively reduce the electromagnetic vibration and noise of the motor.

[0058] This embodiment takes an 8-pole 48-slot slant slot built-in permanent magnet synchronous motor as a prototype of this embodiment. The prototype runs at a speed of 750 / min, at which the fundamental frequency of the motor is 50Hz, the amplitude and frequency of the high-frequency injection voltage signal are 0.2V and 1000Hz, and the PWM is shown in Table 1:

[0059] Table 1: Parameters of the prototype of the embodiment

[0060] Parameter Value Rated power / kW 10 Rated voltage / V 144 Rated speed / (r / min) 3000 Rated current / A 90 Rated torque / (Nm) 32 Number of pole pairs 4 Inner diameter of stator / mm 61.6 Outer diameter of rotor / mm 61.1

[0061] The estimated rotating coordinate system is expressed as u dh = U in cosω h t. According to Figure 1 , the principle diagram of the pulse high-frequency signal injection method shows the steps, in order to extract the position information, the induced high-frequency current estimate value is first filtered through a band-pass filter to filter out the carrier frequency signal far above the injection frequency and the fundamental frequency signal far below the injection frequency, then multiplied by the modulation signal sin(ω h t), and then filtered through a low-pass filter to filter out the high-frequency components to obtain the input required by the PI regulator. The adjustment input is zero, that is, the estimation error of the rotor position angle is zero, at which the actual value of the rotor position angle is equal to the estimated value of the rotor position angle, thereby realizing the estimation of the rotor position and speed.

[0062] The injection of sinusoidal high-frequency voltage excitation will produce new voltage components by interacting with the fundamental frequency signal. Taking phase A as an example, based on Park coordinate transformation, as shown in Figure 2 , compared with the traditional vector control, two new components of 950Hz and 1050Hz are generated after the pulse high-frequency voltage injection, which are expressed as: f h ±f1.

[0063]

[0064] u ah =cosωt·U in ·cosω h t

[0065] =0.5·Uin • [cos(ω h t-ω1t)+cos(ω h t+ω1t)]

[0066] where u ah is the newly generated A-phase voltage component, u dh is the injected high-frequency voltage excitation signal, U in is the amplitude of the injected high-frequency voltage excitation signal, ω h is the frequency of the injected high-frequency voltage excitation signal.

[0067] The pulse high-frequency voltage injection SVPWM strategy will generate additional sideband harmonic components near the switching frequency and its multiples. The phase current harmonic analytical expression cannot be directly derived from the phase voltage harmonic, and the Fourier series is used to derive the phase voltage harmonic in the stator coordinate system. The conventional SVPWM technology can be considered as symmetric placement of zero vectors, unitization, and only the additional injected voltage vector is Fourier expanded based on the carrier frequency ω c

[0068]

[0069] where U dc is the DC bus voltage, a0 / 2 is the periodic average value, a n is the n-th harmonic cosine component. Taking the ω h +ω1 component of the A-phase voltage as an example, through Bessel expansion and ignoring its high-order terms, the sideband voltage harmonic of the A-phase is:

[0070] U as1 ≈C 1_0 cos(ω c t)+C 1_2 cos(ω c t±2(ω h +ω1)t)+C 1_4 cos(ω c t±4(ω h +ω1)t)

[0071] In the formula, the coefficient C is the Bessel function, which represents the amplitude of each order sideband voltage harmonic, and the subscript represents the harmonic number.

[0072] Through Park transformation, the voltage harmonic component in the rotating coordinate system can be obtained as:

[0073]

[0074] where the “±” signs of the 2nd and 4th sideband harmonics are independent of each other, and the 0th harmonic component is 0 in the rotating coordinate system, which represents the initial phase of the space voltage vector.​

[0075] In the case of high frequency voltage injection, ignoring the voltage drop of stator resistance and the permanent magnet flux linkage as the fundamental signal, the PMSM voltage equation in dq coordinate system is expressed as:

[0076]

[0077] Therefore, the current harmonic components in the rotating axis system are:

[0078]

[0079] where, L d , L q are the high frequency inductances of dq axis respectively.

[0080] The sideband current harmonics in the stationary coordinate system are derived by inverse Park transformation, as shown in the following equation: Figure 3 The sideband current harmonic components around the first carrier frequency are expressed as: f c ±2,4f h ±2,4f1, which are listed in Table 2:

[0081] Table 2 Sideband current harmonics introduced by high frequency signal injection

[0082]

[0083] Electromagnetic force wave is the main source of electromagnetic vibration noise of motor, and its expression can be obtained by Maxwell stress tensor method:

[0084]

[0085] B n (θ,t)=f n (θ,t)·λ(θ,t)

[0086] where, p n is the radial electromagnetic force wave, B n , B t are the radial and tangential air gap flux density respectively, μ0is the vacuum permeability, f n represents the air gap magnetomotive force, mainly including the magnetomotive force generated by the rotor permanent magnet and the stator armature magnetomotive force. λ represents the air gap permeance, which is related to the structure of the motor stator and rotor, and can be expressed as:

[0087] λ(θ,t)=Λ0·Λ r (θ,t)·Λ s (θ,t)

[0088]

[0089] where, Λ0is the constant component of air gap permeance, Λr The change in magnetic permeability caused by the rotor's salient pole structure, Λ s The change in magnetic permeability caused by slotting the stator.

[0090] The magnetomotive force generated by a permanent magnet can be expressed as:

[0091]

[0092] In the formula, ν represents the order of the magnetomotive force, and the air gap magnetic flux density generated by the rotor permanent magnet is:

[0093]

[0094] The magnetomotive force generated by the stator current can be expressed as:

[0095]

[0096] In the formula, κ is the spatial order of the current harmonics, and the radial air gap magnetic flux density generated by the stator current is:

[0097]

[0098] cos(((κ±2m)p±lZ)θ-(v±2m)ω1t-θ v )

[0099]

[0100] Among them, B svkml F is the amplitude of the air gap magnetic flux density generated by the stator current. svk This represents the amplitude of the magnetomotive force generated by the stator current.

[0101] Considering only the spatial order p magnetic flux density component generated by the fundamental stator current, it can be simplified to:

[0102]

[0103] Among them, B sv This represents the amplitude of the air gap magnetic flux density generated by the stator current.

[0104] Considering the interaction between the radial air gap magnetic flux density generated by the fundamental wave of the permanent magnet and the radial air gap magnetic flux density generated by the stator current, the resulting electromagnetic force wave can be expressed as:

[0105]

[0106] like Figure 4 As shown, the low-frequency electromagnetic force wave component generated near the injection voltage frequency by the pulsed high-frequency injection can be expressed as: (2p,f h +2f1), (0,f h ) and (2p,-f h+ 2f1); specifically listed in Table 3:

[0107] Table 3 Low frequency electromagnetic force waves introduced by high frequency signal injection

[0108]

[0109] The magnetic motive force generated by the sideband current harmonics can be expressed as:

[0110]

[0111] The radial air gap magnetic flux density generated by the sideband current can be derived as:

[0112]

[0113] cos(((κ±2m)p±lZ)θ-(ω ch ±2mω1)t-θ v )

[0114]

[0115] Considering the interaction between the air gap magnetic flux density generated by the sideband current harmonics and the air gap magnetic flux density generated by the fundamental wave of the permanent magnet, the electromagnetic force waves generated by the sideband current are ultimately obtained as:

[0116]

[0117] As shown in Figure 5 , the sideband electromagnetic force wave components near the first carrier frequency newly generated by the sideband current are expressed as: (2p, ±f c ±2, 4f h -f1), (2p, ±f c ±2, 4f h +5f1), (0, ±f c ±2, 4f h ±3f1); specifically listed in Table 4:

[0118] Table 4 High frequency electromagnetic force waves introduced by high frequency signal injection

[0119]

[0120] The natural modal order and frequency of the motor are obtained by the hammering method at dozens of test points on the four surfaces of the motor in the longitudinal direction. The test points are knocked one by one in the radial direction by a force hammer. When knocking, the excitation force in the motor causes a force response to induce vibration. The signal is transmitted to the data acquisition instrument for analysis and processing by the acceleration sensor, so as to obtain the natural modal frequency of different orders of the motor.

[0121] When the order and frequency of the electromagnetic force wave is close to the inherent modal order and frequency of the motor, the motor resonance is triggered, and large amplitude electromagnetic vibration and noise are generated. Since the frequency of the injected signal is close to the 2nd modal frequency of the motor, the vibration and noise amplitude of the system has a significant increase at the injection frequency and the 2nd modal frequency. The sideband electromagnetic force wave near the sideband frequency of f c -2f h and f c +4f h The sideband electromagnetic force wave near the sideband frequency of f c -2f h and f c +4f h is close to the 0th and 8th modal frequencies of the motor, and the amplitude of the electromagnetic vibration and noise near the sideband frequency increases significantly. Although the amplitude of the sideband current harmonic is much smaller than that of the fundamental and low-frequency current harmonics, when its frequency is close to the modal frequency, the influence on the electromagnetic vibration and noise is still great.

[0122] Based on the analysis of the present application, the operating speed (fundamental frequency) of the motor, the injection frequency and the PWM switching frequency, etc. will affect the frequency of the electromagnetic force wave, and thus affect the electromagnetic vibration and noise of the motor in operation. Reasonably selecting the parameters of the injected signal and the PWM switching frequency can make the frequency of the newly introduced electromagnetic force wave far away from the inherent modal frequency of the motor, thereby reducing the electromagnetic vibration and noise under different operating speeds of the motor.

[0123] Embodiment Two

[0124] The present embodiment provides a system for reducing electromagnetic vibration and noise of a permanent magnet synchronous motor.

[0125] A system for reducing electromagnetic vibration and noise of a permanent magnet synchronous motor, comprising:

[0126] a sideband current harmonic generation module configured to inject a pulsating high-frequency voltage signal under position sensorless control, and the injected pulsating high-frequency voltage signal interacts with the fundamental frequency signal to generate sideband current harmonics near the voltage frequency in the low frequency band and near the PWM switching frequency;

[0127] an interaction module configured to only consider the magnetic flux density component with a spatial order of p generated by the fundamental current of the stator, and interact with the radial air gap magnetic flux generated by the fundamental of the permanent magnet to generate new air gap magnetic flux and electromagnetic force wave order and frequency near the injection voltage frequency;

[0128] an electromagnetic force wave generation module configured to consider the interaction between the air gap magnetic flux generated by the sideband current harmonic and the air gap magnetic flux generated by the fundamental of the permanent magnet to obtain the electromagnetic force wave generated by the sideband current harmonic;

[0129] The control module is configured to: select a suitable frequency of the injected pulse high-frequency voltage signal by comparing parameters under different operating conditions of the permanent magnet synchronous motor, so that the frequency of the electromagnetic force wave generated is far away from the natural modal frequency of the permanent magnet synchronous motor, thereby reducing the electromagnetic vibration and noise of the permanent magnet synchronous motor.

[0130] It should be noted that the above-mentioned sideband current harmonic generation module, interaction module, electromagnetic force wave generation module and control module have the same examples and application scenarios as the steps in Embodiment One, but are not limited to the content disclosed in Embodiment One. It should be noted that the above-mentioned modules as part of the system can be executed in a computer system such as a set of computer executable instructions.

[0131] Embodiment Three

[0132] The embodiment provides a computer readable storage medium, which stores a computer program, and the program is executed by a processor to realize the steps in the method for reducing electromagnetic vibration and noise of a permanent magnet synchronous motor according to Embodiment One.

[0133] Embodiment Four

[0134] The embodiment provides a computer device, which comprises a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor realizes the steps in the method for reducing electromagnetic vibration and noise of a permanent magnet synchronous motor according to Embodiment One when executing the program.

[0135] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system or a computer program product. Therefore, the present application can take the form of a hardware embodiment, a software embodiment or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage and optical storage, etc.) containing computer usable program code.

[0136] The present application is described with reference to flowcharts and / or block diagrams of the method, device (system) and computer program product according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The device for performing the functions specified in one flow or multiple flows and / or blocks. Figure 1 The device for performing the functions specified in one flow or multiple flows and / or blocks.

[0137] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the flow Figure 1 one or more flowcharts and / or blocks Figure 1 one or more flowcharts and / or blocks

[0138] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions that are executed on the computer or other programmable apparatus provide steps for implementing the flow Figure 1 one or more flowcharts and / or blocks Figure 1 one or more flowcharts and / or blocks

[0139] Those skilled in the art can understand that all or part of the flowcharts in the above-mentioned embodiment methods can be completed by computer programs instructing relevant hardware, and the programs can be stored in a computer readable storage medium. When the programs are executed, the flowcharts of the above-mentioned embodiment methods can be included. The storage medium can be a magnetic disc, an optical disc, a read-only memory (ROM) or a random access memory (RAM) and the like.

[0140] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement and the like within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of reducing electromagnetic vibration and noise of a permanent magnet synchronous motor, characterized by, The method comprises the following steps: A pulsating high-frequency voltage signal is injected under position sensorless control, the injected pulsating high-frequency voltage signal interacts with a fundamental frequency signal, and sideband current harmonics are generated near the voltage frequency and near the PWM switching frequency in a low frequency band; Only the space harmonic components of the flux density produced by the stator current fundamental are considered p which interact with the radial air-gap flux density produced by the permanent magnet fundamental, to produce new air-gap flux density and electromagnetic force wave orders and frequencies near the injection voltage frequency; Air gap magnetic density generated by the sideband current harmonics and air gap magnetic density generated by the fundamental frequency of the permanent magnet are considered to interact to obtain electromagnetic force waves generated by the sideband current harmonics; Parameters under different operating conditions of the permanent magnet synchronous motor are compared, and a suitable frequency of the injected pulsating high-frequency voltage signal is selected, so that the frequency of the generated electromagnetic force waves is far away from the natural modal frequency of the permanent magnet synchronous motor, thereby reducing electromagnetic vibration and noise of the permanent magnet synchronous motor; The process of considering the interaction between air gap magnetic density generated by the sideband current harmonics and air gap magnetic density generated by the fundamental frequency of the permanent magnet to obtain electromagnetic force waves generated by the sideband current harmonics is represented by the following formula: wherein, B c0 and B r0 are the air gap flux amplitude generated by the sideband current harmonics and the air gap flux amplitude generated by the fundamental of the permanent magnet, respectively, μ 0 is the vacuum permeability, ω 1 is the fundamental frequency, ω ch are unified to the frequency of the sideband current harmonics.

2. The method of claim 1, wherein, The position sensorless control is that a pulsating high-frequency voltage signal is injected in the estimated two-phase rotating coordinate system direct axis, the voltage drop of the stator resistance is ignored, and the permanent magnet flux linkage is regarded as the fundamental frequency signal, the high-frequency current induced on the cross axis is demodulated to obtain the rotor position information.

3. The method of claim 2, wherein, The process of demodulating the high-frequency current induced on the cross axis comprises the following steps: the high-frequency current on the cross axis is multiplied by a sine signal, then a position deviation signal is extracted through a low-pass filter, finally the position deviation signal is adjusted to 0 through a proportional integral regulator to obtain the rotor position information.

4. The method of claim 1, wherein, The process of interaction between the air-gap magnetic flux generated by the sideband current harmonic and the air-gap magnetic flux generated by the fundamental wave of the permanent magnet to obtain the electromagnetic force wave generated by the sideband current harmonic includes: in the low frequency band, only the electromagnetic force wave generated by the interaction between the radial air-gap magnetic flux generated by the fundamental wave of the permanent magnet and the magnetic flux component with the spatial order of p generated by the stator current fundamental wave is considered; in the high frequency band, only the electromagnetic force wave generated by the interaction between the radial air-gap magnetic flux generated by the fundamental wave of the permanent magnet and the magnetic flux component with the spatial order of p generated by the sideband current harmonic is considered.

5. The method of claim 1, wherein, The air gap magnetic density generated by the sideband current harmonics is radial air gap magnetic density, which is represented by the following formula: wherein, f c is the magnetic motive force generated by the sideband current harmonics, λ is the air-gap permeance, p is the number of pole pairs, Z is the number of stator slots, κ is the spatial order of the magnetic motive force generated by the sideband current harmonics, B ckml is the air-gap flux amplitude generated by the sideband current harmonics, F ck is the magnetic motive force amplitude generated by the sideband current harmonics, Λ r2m is the 2 m nd permeance harmonic amplitude generated by the rotor saliency structure, Λ sl is the l ( l th permeance harmonic amplitude generated by the stator slotting.

6. The method of reducing electromagnetic vibration and noise of a permanent magnet synchronous motor according to claim 1, wherein, The process of obtaining the natural modal frequency of the permanent magnet synchronous motor comprises the following steps: a few dozen test points on the four surfaces of the permanent magnet synchronous motor in the longitudinal direction are knocked by a radial excitation force hammer one by one, the excitation force of the hammer causes a force response in the permanent magnet synchronous motor when knocking, thereby causing vibration, signals are transmitted into a data acquisition instrument by an acceleration sensor for analysis and processing, and thus the natural modal frequencies of different orders of the permanent magnet synchronous motor are obtained.

7. A system for reducing electromagnetic vibration and noise of a permanent magnet synchronous motor, characterized by, The method comprises the following steps: A sideband current harmonic generation module is configured to inject a pulsating high-frequency voltage signal under position sensorless control, the injected pulsating high-frequency voltage signal interacts with a fundamental frequency signal, and sideband current harmonics are generated near the voltage frequency and near the PWM switching frequency in a low frequency band; an interaction module configured to interact only with the stator current fundamental generated space order magnetic density component p with the permanent magnet fundamental generated radial air gap magnetic density, to generate new air gap magnetic density and electromagnetic force wave order and frequency near the injection voltage frequency; An electromagnetic force wave generation module is configured to consider the interaction between air gap magnetic density generated by the sideband current harmonics and air gap magnetic density generated by the fundamental frequency of the permanent magnet to obtain electromagnetic force waves generated by the sideband current harmonics; A control module is configured to compare parameters under different operating conditions of the permanent magnet synchronous motor, select a suitable frequency of the injected pulsating high-frequency voltage signal, and make the frequency of the generated electromagnetic force waves far away from the natural modal frequency of the permanent magnet synchronous motor, thereby reducing electromagnetic vibration and noise of the permanent magnet synchronous motor; The process of considering the interaction between air gap magnetic density generated by the sideband current harmonics and air gap magnetic density generated by the fundamental frequency of the permanent magnet to obtain electromagnetic force waves generated by the sideband current harmonics is represented by the following formula: wherein, B c0 and B r0 are the air gap flux amplitude generated by the sideband current harmonics and the air gap flux amplitude generated by the fundamental of the permanent magnet, respectively, μ 0 is the vacuum permeability, ω 1 is the fundamental frequency, ω ch are unified to the frequency of the sideband current harmonics.

8. A computer readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to implement the steps in the method for reducing electromagnetic vibration and noise of the permanent magnet synchronous motor in any one of claims 1-6.

9. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor implements the steps in the method for reducing electromagnetic vibration and noise of a permanent magnet synchronous motor according to any one of claims 1-6 when executing the program.

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