Method, device and equipment for reducing vibration noise of permanent magnet synchronous motor

Abstract

The invention relates to the technical field of permanent magnet synchronous motors, in particular to a method, device and equipment for reducing vibration noise of a permanent magnet synchronous motor, and the method comprises the steps: building an electromagnetic field model, extracting radial electromagnetic force data, carrying out the spectrum and modal analysis, recognizing a main noise source, generating an acoustic power level waterfall plot through the combination of acoustic simulation, and defining an optimization target. The optimal scheme is finally obtained by designing the shape of a rotor hole, adjusting multi-parameter collaborative optimization of stator slot width and air gap length and the like, and iteratively optimizing key variables by adopting an intelligent algorithm. According to the method, the space 0-order quadruplicated frequency noise and 24-order octupled frequency noise are remarkably reduced, the torque fluctuation is inhibited, the output performance is ensured, the method is suitable for large-scale production, and the NVH quality of the motor is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrode noise reduction, and in particular to a method, device and equipment for reducing vibration noise of a permanent magnet synchronous motor. Background Art

[0002] Permanent magnet synchronous motors (PMSMs) have been widely used in high-end electric vehicles, precision industrial drives, and other fields due to their high efficiency, high power density, and excellent dynamic performance. In recent years, with the continuous advancement of motor technology, flat wire motors, with their rectangular copper wire windings, have demonstrated significant advantages over traditional round wire motors, including higher slot fill rates, improved heat dissipation, and a more compact design. These motors have become a research hotspot in the motor field. However, practical applications of these motors have also exposed some pressing challenges. The high stiffness of the flat wire windings leads to more pronounced vibration coupling with the stator core. This, combined with the inherent electromagnetic excitation of PMSMs (such as magnetic pull harmonics), results in particularly significant noise and vibration (NVH) during motor operation. This noise and vibration not only affects motor smoothness and ride comfort but can also interfere with the normal operation of precision equipment, becoming a key factor hindering the further adoption of flat wire motors in high-end applications. Therefore, effectively reducing the noise and vibration of PMSMs has become a critical technical challenge that needs to be addressed in the current field of motor technology. Summary of the Invention

[0003] The present invention aims to solve the problem of vibration noise of permanent magnet synchronous motor in the prior art and propose a method for reducing vibration noise of permanent magnet synchronous motor, comprising the following steps: S1, based on the detailed dimensions of the permanent magnet synchronous motor, establish an electromagnetic model using finite element simulation software, perform simulation based on the electromagnetic model, and based on the simulation results, check the radial electromagnetic force density in the air gap length, perform a two-dimensional Fourier transform in time and space, and determine the main harmonics that generate torque; S2, perform modal simulation analysis on the permanent magnet synchronous motor, calculate the natural frequency and vibration mode of the motor, and determine whether resonance occurs by checking whether the natural frequency is close to the frequency of the radial electromagnetic force; In S3, radial electromagnetic force data of the permanent magnet synchronous motor at multiple speeds was loaded onto the stator teeth without generating resonance. The remote load was then imported into acoustic simulation software. A sound power level waterfall diagram was generated through acoustic simulation. The main harmonics that generated torque in S1 were compared with the harmonics that affected noise to determine the main harmonics that generated noise. S4, opening auxiliary slots on different axes of the motor rotor, and taking the auxiliary slot radius, auxiliary slot position, stator slot width and air gap length as optimization variables; S5 uses a multi-objective genetic algorithm to optimize the main harmonic noise, torque pulsation suppression, and maximum torque. The optimization goals are to obtain the optimal auxiliary slot radius, auxiliary slot position, stator slot width, and air gap length parameters. The noise before and after optimization are compared to determine whether the vibration noise has been suppressed.

[0004] Preferably, in S1, the permanent magnet synchronous motor is a 48-slot / 16-pole permanent magnet synchronous motor.

[0005] Preferably, the main harmonics generating noise in S3 are the 6th harmonic of the 0th order in space, the 8th harmonic of the 16th order in space, and the 10th harmonic of the 16th order in space.

[0006] Preferably, in S5, auxiliary slots are opened on the d-axis and q-axis of the motor stator, wherein the d-axis is the axis formed by the line connecting the center of the stator slot and the center of the model, and the q-axis is the axis formed by the line connecting the midpoint between the centers of two adjacent stator slots and the center of the model. The torque expression group is:

[0007] (1) Where, is the pole pair number, is the permanent magnet flux, is the direct-axis inductance, is the quadrature-axis inductance, is the direct axis current, is the quadrature axis current, is the average output torque, and are the maximum and minimum torque values, is the torque ripple; The permanent magnet flux formula is (2): (2) Where, is the number of winding turns, is the remanence of the permanent magnet, is the effective cross-sectional area of ​​the air gap.

[0008] Preferably, the optimized variables in S5 are the distance H_q from the center of the q-axis auxiliary hole to the center of the entire model, the distance H_d from the center of the d-axis auxiliary hole to the center of the entire model, the radius R_q of the q-axis auxiliary hole, the radius R_d of the d-axis auxiliary hole, the stator slot opening Bs0 and the air gap length.

[0009] Preferably, obtaining the optimal auxiliary tank parameters in S5 includes the following steps: (1) Initialize the auxiliary hole parameters and randomly generate multiple parameter points; (2) Perform sensitivity analysis to select parameter points that are highly sensitive to the optimized radial electromagnetic force, torque, and torque ripple; (3) Multi-objective genetic algorithm optimization is performed on highly sensitive parameter points, and the optimization objectives are restricted to find the points with minimum radial electromagnetic force, minimum torque ripple, and maximum torque. The optimal solution of the multi-objective genetic algorithm optimization is the set of all Pareto solutions, and the set of all Pareto solutions is obtained; (4) The Pareto solution is visualized and analyzed through the parallel coordinate diagram, a post-processing tool, to demonstrate the trade-off relationship between each variable and the objective function in the multi-objective genetic algorithm optimization. Finally, the optimal auxiliary slot and stator slot width Bs0 and air gap length parameters are obtained, and the accuracy of the results is verified.

[0010] Preferably, the permanent magnet synchronous motor is a flat wire motor, adopts a U-shaped permanent magnet design, the models of the stator and rotor cores are M250-35A_20C and M350-35A_20C respectively, and the casing is made of aluminum alloy.

[0011] A device for reducing vibration noise of a permanent magnet synchronous motor, comprising: a model building unit, configured to build an electromagnetic model using finite element simulation software according to detailed dimensions of the permanent magnet synchronous motor, perform simulation according to the electromagnetic model, and check the radial electromagnetic force density in the air gap length according to the simulation results, perform a two-dimensional Fourier transform in time and space, and determine the main harmonics that generate torque; The resonance judgment unit is used to perform modal simulation analysis on the permanent magnet synchronous motor, calculate the natural frequency and vibration mode of the motor, and determine whether resonance occurs by checking whether the natural frequency is close to the frequency of the radial electromagnetic force; The acoustic simulation unit is used to load the radial electromagnetic force data of the permanent magnet synchronous motor at multiple speeds onto the stator teeth without generating resonance. The remote load is then imported into the acoustic simulation software. The acoustic simulation generates a sound power level waterfall diagram to identify the main harmonics that generate noise. An optimization variable determination unit is used to open auxiliary slots on different axes of the rotor of the motor, and uses the auxiliary slot radius, auxiliary slot position, stator slot width and air gap length as optimization variables; The optimization unit is used to optimize using a multi-objective genetic algorithm with noise minimization, torque pulsation suppression and maximum torque as the optimization goals, and ultimately obtain the optimal auxiliary slot radius, auxiliary slot position, stator slot width and air gap length parameters. The noise optimization before and after is compared to determine whether the vibration noise has been suppressed.

[0012] A device for reducing vibration noise of a permanent magnet synchronous motor comprises a memory and a processor. The memory stores a computer program, and the computer program can be executed by the processor to implement the method for reducing vibration noise of a permanent magnet synchronous motor as described above.

[0013] The present invention has the following beneficial effects: It provides a method for reducing vibration noise in a permanent magnet synchronous motor. This method allows the motor to achieve optimal auxiliary slots, stator slot openings (Bs0), and air gap length parameters, while maintaining basic motor performance while reducing vibration noise. Furthermore, the auxiliary holes only require modification of opening parameters during the rotor lamination design phase, eliminating the need for complex process changes and making them suitable for mass production. Furthermore, by optimizing the rotor auxiliary slots, stator slot openings (Bs0), and air gap length, multi-layer noise suppression can be achieved. Through innovative rotor structure modulation technology, the present invention effectively suppresses motor vibration noise while balancing electromagnetic performance and torque output. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For those skilled in the art, other relevant drawings can be obtained based on these drawings without creative work.

[0015] Figure 1 This is a schematic diagram of the permanent magnet synchronous motor used in the present invention; Figure 2 Schematic diagram of the auxiliary slots of the rotor and the stator slot opening Bs0 of the permanent magnet synchronous motor used in the present invention, as well as the air gap length; Figure 3 It is a workflow diagram of the present invention; Figure 4 A two-dimensional Fourier transform diagram of the radial electromagnetic force of the permanent magnet synchronous motor used in the present invention; Figure 5 The sound power level waterfall diagram of the permanent magnet synchronous motor used in the present invention; Figure 6 3D set diagram of the Pareto solution of the present invention Figure 7 This is a comparison chart of the SPL noise of the motor with the initial structure and the optimized embodiment of the present invention.

[0016] Figure 8 This is a torque comparison diagram of the motor of the initial structure and the optimized embodiment of the present invention.

[0017] In the figure: 1-stator slot; 2-air gap; 3-d-axis auxiliary hole; 4-q-axis auxiliary hole. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by the first technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention for which protection is sought, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by the first technicians in this field without making creative work are within the scope of protection of the present invention.

[0019] Example The following are only preferred embodiments of the present invention. The protection scope of the present invention is not limited to the following embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention.

[0020] Refer to the instruction manual Figure 1-3 The present invention discloses a method for optimizing the design of auxiliary slots in a permanent magnet motor rotor. While maintaining the mechanical strength of the rotor, the method effectively suppresses electromagnetic force waves of a specific order, reduces the noise of the motor operation, and ensures the stability of the torque output by optimizing the auxiliary slot structure. Figure 3 , specifically including the following steps: S1, based on the detailed dimensions of the permanent magnet synchronous motor, an electromagnetic model is established using finite element simulation software. The radial electromagnetic force density in the air gap length is checked based on the simulation results, and a two-dimensional Fourier transform of time and space is performed to check the main harmonics that generate torque; S2, perform modal simulation analysis on the permanent magnet synchronous motor, calculate the natural frequency and vibration mode of the motor, check whether the natural frequency is close to the frequency of the radial electromagnetic force, and determine whether resonance occurs; S3: Load the radial electromagnetic force data of the permanent magnet synchronous motor at multiple speeds onto the stator teeth. Import the remote load into the acoustic simulation software, generate a sound power level waterfall diagram through acoustic simulation, and identify the main harmonics that generate noise. S4, setting the main harmonics, output torque and torque ripple as optimization targets; S5, since the auxiliary slots on the motor rotor have the effect of improving the air gap length magnetic density, reducing the radial electromagnetic force and optimizing the noise, and the air gap length and slot width affect the electromagnetic force as well as the torque, the auxiliary slots are opened on the d and q axes of the motor stator, and the torque expression is:

[0021] (1) Where, is the pole pair number, is the permanent magnet flux, is the direct-axis inductance, is the quadrature-axis inductance, is the direct axis current, is the quadrature axis current, is the average output torque, and are the maximum and minimum torque values, is the torque ripple; The permanent magnet flux formula is (2): (2) Where, is the number of winding turns, is the remanence of the permanent magnet, is the effective cross-sectional area of ​​the air gap.

[0022] Since the air gap length and stator slot width affect the effective cross-sectional area of ​​the air gap, and thus affect the output torque and torque ripple, they are also used as optimization variables; S6 utilizes a multi-objective genetic algorithm (GA) optimization with noise minimization, torque pulsation suppression, and maximum torque as optimization objectives. Ultimately, the optimal auxiliary slot and stator slot openings, as well as the air gap length parameters, are obtained. Comparing the noise optimization results before and after confirms that vibration noise has been suppressed. The process for obtaining the optimal auxiliary slot parameters in S6 is as follows: The auxiliary slot parameters are initialized and 1000 parameter points are randomly generated. A sensitivity analysis is performed to identify parameter points that are highly sensitive to the optimization targets of radial electromagnetic force, torque, and torque pulsation. A GA multi-objective GA optimization is performed on these highly sensitive parameter points, restricting the optimization objectives to finding the point with the minimum radial electromagnetic force, minimum torque pulsation, and maximum torque. The optimal solution for the multi-objective optimization is the set of all Pareto solutions, and the set of all Pareto solutions is obtained. The Pareto front solutions are visualized using a post-processing tool, parallel coordinate plots, to intuitively demonstrate the trade-offs between the variables and the objective function in the multi-objective optimization. Ultimately, the optimal auxiliary slot and stator slot openings, Bs0, and the air gap length parameters are obtained, and the accuracy of the results is verified.

[0023] Specifically, in the present invention, the permanent magnet synchronous motor used is as follows Figure 1 As shown in Table 1 Table 1 Main structural parameters of the implemented motor

[0024] Specifically, according to the main size parameters of the motor in Table 1, simulation modeling was performed using finite element software, and the rated torque was obtained to be 7.73 Nm, the torque ripple was 19%, and the rated current was 36.14 A.

[0025] Specifically, the auxiliary slots on the d and q axes of the motor stator and the stator slot opening Bs0, as well as the air gap length, are shown in the appendix of the manual. Figure 2 , including a stator slot 1, an air gap 2, a d-axis auxiliary hole 3 and a q-axis auxiliary hole 4 (where the q-axis auxiliary hole is a small circle corresponding to the air gap, and the d-axis auxiliary hole is a corresponding dotted large circle); specifically, Figure 4 The horizontal axis is the spatial order of electromagnetic force, and the vertical axis is the time order of electromagnetic force. It can be seen that the radial electromagnetic force is higher in the 6th frequency of the 0th order, the 2nd frequency of the 16th order, the 8th frequency of the 16th order, and the 10th frequency of the 16th order. Figure 5 The figure is a waterfall diagram of the sound power level. It is found that the noise of the motor is more obvious at 6f, 8f, and 10f.

[0026] Specifically, among the radial electromagnetic forces generated by the motor, it is found that the radial electromagnetic forces of the motor are higher at the 6th frequency of the 0th order, the 2nd frequency of the 16th order, the 8th frequency of the 16th order, and the 10th frequency of the 16th order. Figure 4 ), it was determined that the main harmonics contributing to the noise were the 0th-order spatial 6th harmonic, the 16th-order spatial 8th harmonic, and the 16th-order spatial 10th harmonic. Therefore, these three harmonic components were set as the final optimization targets, with the 0th-order spatial 6th harmonic being the primary target. Combined with the requirement for low torque ripple, the final optimization targets for torque and torque ripple were set.

[0027] Specifically, according to the multi-objective genetic algorithm (NSGA-II) optimization, the set of all Pareto solutions is obtained, as shown in the appendix of the manual. Figure 6 As shown in the figure, the Pareto front solution is visualized and analyzed through the post-processing tool Parallel Coordinates Plot to intuitively show the trade-off relationship between each variable and the objective function in the multi-objective optimization, thereby obtaining the optimal auxiliary slot and stator slot size Bs0, as well as the air gap length parameters.

[0028] As shown in Table 2, the four groups of optimization variables of the rotor auxiliary slot and the stator slot opening and air gap length are set as optimization targets. H_q represents the distance from the center of the q-axis auxiliary hole to the center of the entire model, in mm; H_d represents the distance from the center of the d-axis auxiliary hole to the center of the entire model, in mm; R_q represents the radius of the q-axis auxiliary hole, in mm; R_d represents the radius of the d-axis auxiliary hole, in mm; Bs0 represents the stator slot opening width, in mm; and Q_x represents the air gap length, in mm.

[0029] Table 2 Comparison of permanent magnet synchronous motor before and after optimization

[0030] Specifically, according to the table, it can be seen that by opening auxiliary holes on the rotor d and q axes, the motor noise can be optimized and the torque performance of the motor can be guaranteed. Figure 7 As shown in the figure, the noise peak value dropped from 61.4dBA to 49dBA, a year-on-year decrease of 20%. Figure 8 As shown in the figure, the torque performance of the motor remains basically unchanged, although the output torque of the motor is slightly reduced, the torque ripple is reduced at the same time.

[0031] In summary, this paper addresses the vibration and noise issues of permanent magnet motors by developing a comprehensive design method based on rotor auxiliary slot optimization. Through multi-parameter collaborative optimization, this method suppresses electromagnetic harmonics and reduces torque ripple while improving the motor's output characteristics. This approach can provide a solution for low-noise, high-precision applications such as electric vehicle drive motors.

[0032] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A method for reducing vibration noise of a permanent magnet synchronous motor, characterized in that: The steps include: S1, based on the detailed dimensions of the permanent magnet synchronous motor, establish an electromagnetic model using finite element simulation software, perform simulation based on the electromagnetic model, and based on the simulation results, check the radial electromagnetic force density in the air gap length, perform a two-dimensional Fourier transform in time and space, and determine the main harmonics that generate torque; S2, perform modal simulation analysis on the permanent magnet synchronous motor, calculate the natural frequency and vibration mode of the motor, and determine whether resonance occurs by checking whether the natural frequency is close to the frequency of the radial electromagnetic force; In S3, radial electromagnetic force data of the permanent magnet synchronous motor at multiple speeds was loaded onto the stator teeth without generating resonance. The remote load was then imported into acoustic simulation software. A sound power level waterfall diagram was generated through acoustic simulation. The main harmonics that generated torque in S1 were compared with the harmonics that affected noise to determine the main harmonics that generated noise. S4, opening auxiliary slots on different axes of the motor rotor, and taking the auxiliary slot radius, auxiliary slot position, stator slot width and air gap length as optimization variables; S5 uses a multi-objective genetic algorithm to optimize the main harmonic noise, torque pulsation suppression, and maximum torque. The optimization goals are to obtain the optimal auxiliary slot radius, auxiliary slot position, stator slot width, and air gap length parameters. The noise before and after optimization are compared to determine whether the vibration noise has been suppressed.

2. The method for reducing vibration noise of a permanent magnet synchronous motor according to claim 1, wherein: In S1, the permanent magnet synchronous motor is a 48-slot / 16-pole permanent magnet synchronous motor.

3. The method for reducing vibration noise of a permanent magnet synchronous motor according to claim 1, wherein: The main harmonics that generate noise in S3 are the 6th harmonic of the 0th order, the 8th harmonic of the 16th order, and the 10th harmonic of the 16th order.

4. The method for reducing vibration noise of a permanent magnet synchronous motor according to claim 1, wherein: In S5, auxiliary slots are opened on the d-axis and q-axis of the motor stator, where the d-axis is the axis formed by the line connecting the center of the stator slot and the center of the model, and the q-axis is the axis formed by the line connecting the midpoint between the centers of two adjacent stator slots and the center of the model. The torque expression group is: （1） Where, is the pole pair number, is the permanent magnet flux, is the direct-axis inductance, is the quadrature-axis inductance, is the direct axis current, is the quadrature axis current, is the average output torque, and are the maximum and minimum torque values, is the torque ripple; The permanent magnet flux formula is (2): （2） Where, is the number of winding turns, is the remanence of the permanent magnet, is the effective cross-sectional area of ​​the air gap.

5. The method for reducing vibration noise of a permanent magnet synchronous motor according to claim 4, characterized in that: The optimized variables in S5 are the distance H_q from the center of the q-axis auxiliary hole to the center of the entire model, the distance H_d from the center of the d-axis auxiliary hole to the center of the entire model, the radius of the q-axis auxiliary hole R_q, the radius of the d-axis auxiliary hole R_d, the stator slot opening Bs0, and the air gap length.

6. The method for reducing vibration noise of a permanent magnet synchronous motor according to claim 1, characterized in that: The steps to obtain the optimal auxiliary tank parameters in S5 include the following: (1) Initialize the auxiliary hole parameters and randomly generate multiple parameter points; (2) Perform sensitivity analysis to select parameter points that are highly sensitive to the optimized radial electromagnetic force, torque, and torque ripple; (3) Multi-objective genetic algorithm optimization is performed on highly sensitive parameter points, and the optimization objectives are restricted to find the points with minimum radial electromagnetic force, minimum torque ripple, and maximum torque. The optimal solution of the multi-objective genetic algorithm optimization is the set of all Pareto solutions, and the set of all Pareto solutions is obtained; (4) The Pareto solution is visualized and analyzed through the parallel coordinate diagram, a post-processing tool, to demonstrate the trade-off relationship between each variable and the objective function in the multi-objective genetic algorithm optimization. Finally, the optimal auxiliary slot and stator slot width Bs0 and air gap length parameters are obtained, and the accuracy of the results is verified.

7. The method for reducing vibration noise of a permanent magnet synchronous motor according to claim 1, characterized in that: The permanent magnet synchronous motor is a flat wire motor, adopts a U-shaped permanent magnet design, the models of the stator and rotor cores are M250-35A_20C and M350-35A_20C respectively, and the casing is made of aluminum alloy.

8. A device for reducing vibration noise of a permanent magnet synchronous motor, characterized in that: include: a model building unit, configured to build an electromagnetic model using finite element simulation software according to detailed dimensions of the permanent magnet synchronous motor, perform simulation according to the electromagnetic model, and check the radial electromagnetic force density in the air gap length according to the simulation results, perform a two-dimensional Fourier transform in time and space, and determine the main harmonics that generate torque; The resonance judgment unit is used to perform modal simulation analysis on the permanent magnet synchronous motor, calculate the natural frequency and vibration mode of the motor, and determine whether resonance occurs by checking whether the natural frequency is close to the frequency of the radial electromagnetic force; The acoustic simulation unit is used to load the radial electromagnetic force data of the permanent magnet synchronous motor at multiple speeds onto the stator teeth without generating resonance. The remote load is then imported into the acoustic simulation software. The acoustic simulation generates a sound power level waterfall diagram to identify the main harmonics that generate noise. An optimization variable determination unit is used to open auxiliary slots on different axes of the rotor of the motor, and uses the auxiliary slot radius, auxiliary slot position, stator slot width and air gap length as optimization variables; The optimization unit is used to optimize using a multi-objective genetic algorithm with noise minimization, torque pulsation suppression and maximum torque as the optimization goals, and ultimately obtain the optimal auxiliary slot radius, auxiliary slot position, stator slot width and air gap length parameters. The noise optimization before and after is compared to determine whether the vibration noise has been suppressed.

9. A device for reducing vibration noise of a permanent magnet synchronous motor, characterized in that: The method comprises a memory and a processor, wherein a computer program is stored in the memory and the computer program can be executed by the processor to implement the method for reducing vibration noise of a permanent magnet synchronous motor according to any one of claims 1 to 7.

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